Aetna considers any of the following injections or procedures medically necessary for the treatment of back pain; provided, however, that only one invasive modality or procedure will be considered medically necessary at a time.

1. Facet joint injections are considered medically necessary in the management of chronic back or neck pain (pain lasting more than 3 months despite appropriate conservative treatment) when used either:

   1. As a diagnostic trial to determine the origin of the member's pain, to establish the effectiveness of the facet injections in relieving the member's pain, and to achieve a therapeutic effect; or

   2. As a therapeutic injection to facilitate a comprehensive pain management program (not as an isolated treatment), including physical therapy, patient education, psychosocial support, and oral medication where appropriate.

   Facet joint injections are considered experimental and investigational for all other indications.

   A set of facet joint injections means up to 6 injections per sitting, and this can be repeated up to four times to establish the diagnosis and achieve therapeutic effect. It is not considered medically necessary to repeat facet joint injections more frequently than once every 7 days.  Additional sets of facet injections are not considered medically necessary if no clinical response is achieved. Once a diagnosis is established, it is rarely considered medically necessary to repeat facet injections more frequently than once every two months. Repeat injections extending beyond 12 months may be reviewed for continued medical necessity. Consistent with the Agency for Healthcare Research and Quality (AHRQ) guideline on the treatment of acute back pain, Aetna considers facet joint injections experimental and investigational for the treatment of acute back pain, defined as back pain of less than 3 months' duration.

2. Trigger point injections of corticosteroids and/or local anesthetics, are considered medically necessary for treating members with chronic neck or back pain or myofascial pain syndrome, when all of the following selection criteria are met:

   1. Trigger points have been identified by palpation, and
   2. Symptoms have persisted for more than 3 months, and
   3. Conservative therapies such as bed rest, exercises, heating or cooling modalities, massage, and pharmacotherapies such as non-steroidal anti-inflammatory drugs, muscle relaxants, non-narcotic analgesics, should have been tried and failed; and

   4. Trigger point injections are not administered in isolation, but are provided as part of a comprehensive pain management program, including physical therapy, patient education, psychosocial support, and oral medication where appropriate.

   Trigger point injections are considered experimental and investigational for all other indications.

   A trigger point is defined as a specific point or area where, if stimulated by touch or pressure, a painful response will be induced. A set of trigger point injections means injections in several trigger points in one sitting. It is not considered medically necessary to repeat injections more frequently than every 7 days. Up to four sets of injections are considered medically necessary to diagnose the origin of a patient's pain and achieve a therapeutic effect; additional sets of trigger point injections are not considered medically necessary if no clinical response is achieved. Once a diagnosis is established and a therapeutic effect is achieved, it is rarely considered medically necessary to repeat trigger point injections more frequently than once every two months. Repeated injections extending beyond 12 months may be reviewed for continued medical necessity.

3. Sacroiliac joint injections are considered medically necessary to relieve pain associated with lower lumbosacral disturbances in members who meet both of the following criteria:

   1. Member has back pain for more than 3 months; and
   2. The injections are not used in isolation, but are provided as part of a comprehensive pain management program, including physical therapy, patient education, psychosocial support, and oral medication where appropriate.

   Sacroiliac joint injections are considered experimental and investigational for all other indications.

   Up to two sacroiliac injections are considered medically necessary to diagnose the patient's pain and achieve a therapeutic effect. It is not considered medically necessary to repeat these injections more frequently than once every 7 days. If the member experiences no symptom relief or functional improvement after two sacroiliac joint injections, additional sacroiliac joint injections are not considered medically necessary. Once the diagnosis is established, it is rarely medically necessary to repeat sacroiliac injections more frequently than once every two months. Repeat injections extending beyond 12 months may be reviewed for continued medical necessity.

4. Epidural injections of corticosteroid preparations (e.g., Depo-Medrol), with or without added anesthetic agents, are considered medically necessary in the outpatient setting for management of back or neck pain when all of the following are met:

   1. Intraspinal tumor or other space-occupying lesion, or non-spinal origin for pain, has been ruled out as the cause of pain; and
   2. Member has failed to improve after two or more weeks of conservative measures (e.g., rest, systemic analgesics and/or physical therapy); and

   3. Epidural injections beyond the first set of three injections are provided as part of a comprehensive pain management program, which includes physical therapy, patient education, psychosocial support, and oral medications, where appropriate.

   Epidural injections of corticosteroid preparations, with or without added anesthetic agents, are considered experimental and investigational for all other indications.

   Repeat epidural injections beyond the first set of three injections are considered medically necessary when provided as part of a comprehensive pain management program, which includes physical therapy, patient education, psychosocial support, and oral medications, where appropriate. Repeat epidural injections more frequently than every 7 days are not considered medically necessary. Up to three epidural injections are considered medically necessary to diagnose a member's pain and achieve a therapeutic effect; if the member experiences no pain relief after three epidural injections, additional epidural injections are not considered medically necessary. Once a therapeutic effect is achieved, it is rarely medically necessary to repeat epidural injections more frequently than once every two months. In selected cases where more definitive therapies (e.g., surgery) cannot be tolerated or provided, additional epidural injections may be considered medically necessary. Repeat injections extending beyond 12 months may be reviewed for continued medical necessity. 

   See also CPB 722 - Selective Nerve Root Blocks

5. Chymopapain chemonucleolysis is considered medically necessary for the treatment of sciatica due to a herniated disc when all of the following are met:

   1. Member has leg pain worse than low back pain; and
   2. Member has radicular symptoms reproduced by sciatic stretch tests; and
   3. Member has only a single level herniated disc with nerve root impingement at clinically suspected level demonstrated by MRI, CT, or myelography; and
   4. Member has objective neurologic deficit (e.g., diminished DTR, motor weakness, or hypalgesia in dermatomal distribution); and

   5. Pain not relieved by at least 6 weeks of conservative therapy.

   Chymopapain chemonucleolysis is considered experimental and investigational for all other indications, including the following:

   1. Acute low back pain alone
   2. When performed with chondroitinase ABC or agents other than chymopapain
   3. For herniated thoracic or cervical discs
   4. Cauda equina syndrome
   5. Sequestered disc fragment
   6. Multiple back operations (failed back surgery syndrome)
   7. Neurologic disease (e.g., multiple sclerosis)
   8. Pregnancy
   9. Profound or rapidly progressive neurologic deficit
   10. Severe spondylolisthesis
   11. Spinal cord tumor
   12. Spinal instability

   13. Severe spinal stenosis.

6. Percutaneous lumbar discectomy, manual or automated, is considered medically necessary for treatment of herniated lumbar discs when all of the following are met:

   1. Member is otherwise a candidate for open laminectomy; and

   2. Member has failed 6 months of conservative management; and

   3. Diagnostic studies show that the nuclear bulge of the disc is contained within the annulus (i.e., the herniated disc is contained); and

   4. Member has no previous surgery or chemonucleolysis of the disc to be treated; and

   5. Member must have typical clinical symptoms of radicular pain corresponding to the level of disc involvement.
      
      Percutaneous lumbar diskectomy is considered experimental and investigational for all other indications.
      
      Note: Clinical studies have not established any clinically significant benefit of use of a laser over use of a scalpel for percutaneous lumbar diskectomy. .

7. Nonpulsed radiofrequency facet denervation (also known as facet neurotomy, facet rhizotomy, or articular rhizolysis) is considered medically necessary for treatment of members with intractable cervical or back pain with or without sciatica in the outpatient setting when all of the following are met:

   1. Member has experienced severe pain limiting activities of daily living for at least 6 months; and
   2. Member has had no prior spinal fusion surgery; and
   3. Neuroradiologic studies are negative or fail to confirm disc herniation; and
   4. Member has no significant narrowing of the vertebral canal or spinal instability requiring surgery; and
   5. Member has tried and failed conservative treatments such as bed rest, back supports, physiotherapy, correction of postural abnormality, as well as pharmacotherapies (e.g., anti-inflammatory agents, analgesics and muscle relaxants); and

   6. Trial of facet joint injections has been successful in relieving the pain.

   Nonpulsed radiofrequency facet denervation is considered experimental and investigational for all other indications.

   Only 1 treatment procedure per level per side is considered medically necessary in a 6-month period.
   
   See also CPB 735 - Pulsed Radiofrequency.

8. Implantable infusion pumps are considered medically necessary when used to administer opioid drugs (e.g., morphine) intrathecally or epidurally for treatment of severe chronic intractable pain of malignant or non-malignant origin in members with life expectancies of more than 3 months who have proven unresponsive to less invasive medical therapy as determined by the following criteria:

   1. Member's history must indicate that he/she would not respond adequately to non-invasive methods of pain control, such as systemic opioids (including attempts to eliminate physical and behavioral abnormalities which may cause an exaggerated reaction to pain); and

   2. A preliminary trial of intraspinal opioid drug administration must be undertaken with a temporary intrathecal/epidural catheter to substantiate adequately acceptable pain relief, the degree of side effects (including effects on the activities of daily living), and member's acceptance.

   Implantable infusion pumps for intrathecal or epidural infusion of opoids are considered experimental and investigational for all other indications.

9. Pedicle screws for spinal fixation are considered medically necessary for the following indications:

   1. Spondylolisthesis -- grades I-IV
   2. Spinal trauma of all types including fractures and dislocations
   3. Thoracic fractures
   4. Scoliosis and kyphosis requiring spinal instrumentation
   5. Segmental defects or loss of posterior elements following tumor resection
   6. Fusion after decompression
   7. Pseudoarthrosis repair
   8. Revision lumbar disc surgery requiring instrumentation because of instability at the previous level of surgery

   9. Fusion adjacent to prior lumbar fusion.

   Pedicle screw fixation is considered experimental and investigational for all other indications, including the following:

   1. First time intervertebral disc herniation
   2. Degenerative disc disease
   3. Single level discectomy
   4. Isolated low back pain without spinal instability or neurologic deficits
   5. Failed lumbar surgery without documentation of instability pattern or pseudarthrosis

   6. Decompressive laminectomy for spinal stenosis without evidence of instability.

10. Intervertebral body fusion devices (spine cages) (e.g., BAK Interbody Fusion System; Ray Threaded Fusion Cage) are considered medically necessary for use with autogenous bone graft in members with degenerative disc disease at one or two adjoining levels from L2-S1, with up to Grade 1 spondylolisthesis or retrolisthesis at the involved levels, implanted by an open anterior or posterior approach. Spine cages are considered experimental and investigational for all other indications.

11. Percutaneous polymethylmethacrylate vertebroplasty (PPV) or kyphoplasty is considered medically necessary for members with persistent, debilitating pain in the cervical, thoracic or lumbar vertebral bodies resulting from any of the following:

    1. Primary malignant neoplasm of bone or bone marrow; or
    2. Secondary osteolytic metastasis, excluding sacrum and coccyx; or
    3. Multiple myeloma; or
    4. Painful and/or aggressive hemangiomas; or
    5. Painful, debilitating osteoporotic collapse/compression fractures (e.g., Kummell's disease); or
    6. Steroid-induced fractures; or
    7. Painful vertebral eosinophilic granuloma with spinal instability; or
    8. Traumatic fracture; or

    9. As a reinforcement or stabilization of vertebral body prior to surgery.

    AND all of the following criteria have been met:

    1. Severe debilitating pain or loss of mobility that cannot be relieved by optimal medical therapy (e.g., acetaminophen, NSAIDS, narcotic analgesics, braces, physical therapy, etc.); and
    2. Other causes of pain such as herniated intervertebral disk have been ruled out by computed tomography or magnetic resonance imaging; and

    3. The affected vertebra has not been extensively destroyed and is at least one-third of its original height.

See also CPB 743 Spinal Surgery: Laminectomy and Fusion.

Experimental and Investigational Interventions

Aetna considers any of the following injections or procedures experimental and investigational: 

1. Thermal intradiscal procedures (TIPs) for relief of discogenic pain or other indications.  TIPs are also known as:

   1. Intradiscal electrothermal annuloplasty (IEA),
   2. Intradiscal electrothermal therapy (IDET),
   3. Intradiscal thermal annuloplasty (IDTA), 
   4. Percutaneous intradiscal radiofrequency thermocoagulation (PIRFT),
   5. Percutaneous radiofrequency thermomodulation,
   6. Coblation percutaneous disc decompression,
   7. Nucleoplasty (See CPB 602 - Nucleoplasty),
   8. Radiofrequency annuloplasty (RA), 
   9. Intradiscal biacuplasty (IDB), 
   10. Percutaneous (or plasma) disc decomression (PDD),

   11. Targeted disc decompression (TDD).

   Note: TIPs are also identified or labeled based on the name of the catheter/probe that is used (e.g., SpineCath, discTRODE, Accuthem, or TransDiscal electrodes).

2. Radiofrequency lesioning of dorsal root ganglia for back pain.
3. Radiofrequency lesioning of terminal (peripheral) nerve endings for back pain.
4. Epiduroscopy (also known as epidural spinal endoscopy, spinal endoscopy, myeloscopy, and epidural myeloscopy) for the diagnosis and treatment of intractable low back pain or other indications.
5. Epidural injections of lytic agents (e.g., hypertonic saline, hyaluronidase) or mechanical lysis in the treatment of epidural fibrosis, adhesive arachnoiditis, failed back syndrome, or other indications.
6. Percutaneous endoscopic diskectomy with or without laser (PELD) (also known as arthroscopic microdiskectomy or Yeung Endoscopic Spinal Surgery System (Y.E.S.S.)).
7. Microsurgical anterior foraminotomy for cervical spondylotic myelopathy or other indications.
8. Sacroiliac fusion for the treatment of low back pain due to sacroiliac joint syndrome. Note: Sacroiliac fusion may be medically necessary for sacroiliac pain due to severe traumatic injury, where a trial of an external fixator is successful in providing pain relief.
9. Sacroplasty for osteoporotic sacral insufficiency fractures and other indications.
10. Racz procedure (epidural adhesiolysis with the Racz catheter) for the treatment of members with epidural adhesions, adhesive arachnoiditis, failed back syndrome from multiple previous surgeries for herniated lumbar disk, or other indications.
11. Microendoscopic discectomy (MED) procedure for decompression of lumbar spine stenosis, lumbar disc herniation, or other indications.
12. Dynamic stabilization (e.g., Dynesys Spinal System).
13. Inter-spinous distraction (e.g., X Stop Device, Coflex interspinous stabilization spinal implant) for spinal stenosis or other indications.
14. Endoscopic laser foraminoplasty.
15. Piriformis muscle resection.

16. Xclose Tissue Repair System.

Reimbursement Notes:

• Laser: Clinical studies have not established a clinically significant benefit of use of a laser over a scalpel in spinal surgery. No additional benefit will be provided for the use of a laser in spinal surgery.
• Microscope and endoscope: Use of a microscope or endoscope is considered an integral part of the spinal surgery and not separately reimbursable.

Epidural Steroids

An epidural steroid injection is an injection of long lasting steroid in the epidural space – that is the area which surrounds the spinal cord and the nerves coming out of it. The efficacy of epidurally administered steroids has been demonstrated without adverse consequence in a large number of patients with reproducible results. In a large number of studies, long-term relief of pain (greater than 3 months) can be achieved in at least 10-30% of patients, while short-term relief (less than 1 month) can be achieved in 60-100% of patients. Results for cervical pain are somewhat lower than those for lumbar pain. Such therapy is considered under accepted guidelines to be indicated in patients with low back and cervical pain that has not resolved after only a short period of more conservative measures since studies have shown a better response to therapy in patients whose pain is of shorter duration. Even if pain relief is temporary, it may have long-term benefit because it allows initiation of physical therapy or other rehabilitative measures at an earlier stage. Most authors indicate that a limit on number of injections is appropriate, and that most patients will respond with three or fewer injections.

The American Academy of Neurology's assessment on the use of epidural steroid injections in the treatment of radicular lumbosacral pain (Armond, et al., 2007) concluded that:

• Epidural steroid injections may result in some improvement in radicular lumbosacral pain when determined between 2 and 6 weeks following the injection, compared to control treatment (Level C, Class I–III evidence). The average magnitude of effect is small, and the generalizability of the observation is limited by the small number of studies, limited to highly selected patient populations, the few techniques and doses studied, and variable comparison treatments.
• In general, epidural steroid injections for radicular lumbosacral pain have shown no impact on average impairment of function, on need for surgery, or on long-term pain relief beyond 3 months. Their routine use for these indications is not recommended (Level B, Class I–III evidence).
• Data on use of epidural steroid injections to treat cervical radicular pain are inadequate to make any recommendation (Level U).

Trigger Point Injections

Trigger point injections are injections of local anesthetic medication, saline, and/or steroids into trigger points. A myofascial trigger point is a discrete focal tenderness, 2-5 mm in diameter that is located in distinct tight bands or knots of skeletal muscle (AHFMR, 2002). When palpated, these hyper-irritable areas cause pain in distant areas, or referred pain zones, which are specific for each trigger point. Trigger point injection, or direct wet needling, involves injection of fluid directly into the trigger point located in the taut muscle band. The main objective of trigger point injection is fast pain relief and elimination of muscle spasm in order to break the pain cycle. This facilitates physical therapy aimed at reducing muscle contracture and increasing range of motion. Trigger point injection is rarely used in isolation but is generally part of a multi-disciplinary approach aimed at treating both the trigger points and reducing all contributing factors (Scott & Guo, 2005; AHFMR, 2002; Sanders, et al., 1999). Thus, treatment may also include patient education, psychosocial support, oral medications, and physical therapy to improve the strength and flexibility of the affected musculoskeletal systems. An assessment conducted by the Alberta Heritage Foundation for Medical Research (Scott & Guo, 2005) found that the evidence for the effectiveness of trigger point injections when used as the sole treatment for patients with chronic head, neck, and shoulder pain and whiplash syndrome was inconclusive, regardless of whether sterile water, saline, or botulinum toxin is injected. The assessment found that the combined use of dry needling and trigger point injection with procaine offers no obvious clinical benefit in the treatment of chronic craniofacial pain, while the effectiveness of trigger point injection for the treatment of cervicogenic headache is unknown. In contrast, the assessment found that trigger point injection with lidocaine may be useful in the treatment of joint pain caused by osteoarthritis (Scott & Guo, 2005). The assessment found no proof that triggers point injection is more effective than other less invasive treatments, such as physical therapy and ultrasound, in achieving pain relief, and there is some suggestion that the only advantage of injecting anesthetic into trigger points is that it reduces the pain of the needling process (Scott & Guo, 2005). Usually, approximately three treatments are necessary to abolish a trigger point completely (AHFMR, 2002). A number of trigger points may be injected in one session, but rarely more than five. Repeated injections in a particular muscle are not recommended if two or three previous attempts have been unsuccessful (Alvarez & Rockwell, 2002; Sanders, et al., 1999). The pain relief may last for the duration of the anesthetic to many months, depending on the chronicity and severity of the trigger points and the concomitant treatment of perpetuating factors. According to available guidelines, use of trigger point injections should be short term and part of a comprehensive rehabilitation program. Available guidelines indicate that, while there are a number of uncontrolled case studies using trigger point injections in more acute pain presentations, there is virtually no consistent evidence for its application with chronic non-malignant pain syndrome patients to date (Sanders, et al., 1999; AHFMR, 2002).

Lumbar Laminectomy with or without Fusion

Most individuals with acute low back problems spontaneously recover activity tolerance within 4-6 weeks of conservative therapy (AHCPR, 1994). Conservative therapy for acute low back pain includes:

• Limited bed rest with gradual return to normal activities
• Low impact exercise as tolerated (e.g., walking, swimming, stationary bike)
• Avoidance of activities that aggravate pain
• Cognitive support and reassurance that recovery is expected
• Heat/cold modalities for home use
• Chiropractic manipulation in the first 4 weeks if no radiculopathy
• Non-narcotic analgesics
• Pharmacotherapy (e.g., non-narcotic analgesics, NSAIDs (as second-line choices), avoid muscle relaxants, or only use during the first week, avoid narcotics)
• Exercise program
• Education regarding spine biomechanics.

If conservative therapy fails to relieve symptoms of sciatica and radiculopathy and there is strong evidence of dysfunction of a specific nerve root confirmed at the corresponding level by findings demonstrated by CT/MRI, lumbar laminectomy may be proposed as a treatment option. The goal of lumbar laminectomy is to provide decompression of the affected nerve root to relieve the individual's symptoms. It involves the removal of all or part of the lamina of a lumbar vertebra. The addition of fusion with or without instrumentation is considered when there are concerns about instability.

Decompression with or without Discectomy for Cauda Equine Syndrome

Cauda equina ("horse's tail") is the name given to the lumbar and sacral nerve roots within the dural sac caudal to the conus medullaris. Cauda equina syndrome is usually the result of a ruptured, midline intervertebral disk, most commonly occurring at the L4-L5 level. However, tumors and other compressive masses may also cause the syndrome. Individuals generally present with progressive symptoms of fecal or urinary incontinence, impotence, distal motor weakness, and sensory loss in a saddle distribution. Muscle stretch reflexes may also be reduced. The presence of urinary retention is the single most consistent finding (Perron and Huff, 2002).

In acute cauda equine syndrome, surgical decompression as soon as possible is recommended. In a more chronic presentation with less severe symptoms, decompression could be performed when medically feasible and should be delayed to optimize the patient's medical condition; with this precaution, decompression is less likely to lead to irreversible neurological damage (Dawodu, 2005).

Cervical Laminectomy with or without Fusion

A cervical laminectomy (may be combined with an anterior approach) is sometimes performed when acute cervical disc herniation causes central cord syndrome or in cervical disc herniations refractory to conservative measures. Studies have shown that an anterior discectomy with fusion is the recommended procedure for central or anterolateral soft disc herniation, while a posterior laminotomy-foraminotomy may be considered when technical limitations for anterior access exist (e.g., short thick neck) or when the individual has had prior surgery at the same level (Windsor, 2006).

Discectomy alone is regarded as a technique that most frequently results in spontaneous fusion (70-80%). Additional fusion techniques include the use of bone grafts (autograft, allograft or artificial) with or without cages and/or the use of an anterior plate. A Cochrane systematic review (2004) reported the results of fourteen studies (n=939) that evaluated three comparisons of different fusion techniques for cervical degenerative disc disease and concluded that discectomy alone has a shorter operation time, hospital stay, and post-operative absence from work than discectomy with fusion with no statistical difference for pain relief and rate of fusion. The authors concluded that more conservative techniques (discectomy alone, autograft) perform as well or better than allograft, artificial bone, and additional instrumentation; however, the low quality of the trials reviewed prohibited extensive conclusions and more studies with better methodology and reporting are needed.

Chemonucleolysis

Chemonucleolysis is a procedure that involves the dissolving of the gelatinous cushioning material in an intervertebral disk by the injection of chymopapain or other enzyme. The AHCPR evidence-based guideline on the management of acute back pain and the medical literature supports the use of chemonucleolysis (CNL) with chymopapain as a safe and effective alternative to surgical disc excision in the majority of patients who are candidates for surgery for intractable sciatica due to herniated nucleus pulposus (HNP). Chemonucleolysis involves the enzymatic degradation of the nucleus pulposus, and has been shown to be more effective than percutaneous discectomy since it can be successfully performed for protruded and extruded discs, just as long as the herniated disc material is still in continuity with the disc of its origin. Following CNL, in many cases, relief of sciatica is immediate; however, in up to 30% of patients, maximal relief of symptoms may take up to 6 weeks. The overall success rate for CNL in long-term follow-up (7-20 years) in 3,130 patients from 13 contributors averaged 77% (range 71-93%), the same as that reported for surgical discectomy. In the United States, CNL is approved by the FDA for use in the lumbar spine only.

Facet Blocks

A facet block is an injection of local anesthetic and/or steroids into the facet joint of the spine. Degenerative changes in the posterior lumber facet joints have been established as a source of low back pain that may radiate to the leg. Pain impulses from the medial branches of lumbar dorsal rami can be interrupted by blocking this nerve with anesthetic (facet block) or coagulating it nerve with a radiofrequency wave (radiofrequency facet denervation). Typically, facet joint blocks are performed as a part of a workup for back or neck pain (Wagner, 2003). Pain relief following a precise intra-articular injection of local anesthetic confirms the facet joint as the source of pain. Although some physicians advocate the use of only local anesthetic, most practitioners inject steroids as well, attempting to provide longer pain relief. Long-term relief (6 months) can be obtained in 30-50% of patients (Wagner, 2003). Based on the outcome of a facet joint nerve block, if the patient gets sufficient relief of pain but the pain recurs, denervation of the facet joint may be considered.

Radiofrequency Facet Denervation

Facet joints of the spine have joint capsules that are supplied by a branch of the posterior ramus of the spinal nerve.  Percutaneous radiofrequency facet denervation, also known as radiofrequency facet joint rhizotomy or facet neurotomy, involves selective denervation using radiofrequency under fluoroscopic guidance. As a method of neurolysis, radiofrequency facet denervation has been shown to be a very safe procedure and can offer relief for many patients with mechanical low back pain in whom organic pathology, most commonly a herniated lumbar disc, has been eliminated. According to the literature, it offers advantages over conventional neurolytic agents (e.g., phenol, alcohol, and hypertonic saline) because of its long lasting effects, the relative lack of discomfort, and its completely local action without any random diffusion of the neurolytic agent. Because there are no reliable clinical signs that confirm the diagnosis, successful relief of pain by injections of an anesthetic agent into the joints are necessary before proceeding with radiofrequency facet denervation. Results from many studies have shown that radiofrequency facet denervation results in significant (excellent or good) pain relief, reduced use of pain medication, increased return-to-work, and is associated with few complications. Success rate, however, depends on a careful selection of patients.

Pedicle Screw Fixation

Pedicle screw fixation systems consist of steel or titanium plates that are longitudinally interconnected and anchored to adjacent vertebrae using bolts, hooks, or screws. Pedicle screw fixation in the spine is used to produce a rigid connection between two or more adjacent vertebrae in order to correct deformity and to stabilize the spine, thereby reducing pain and any neurological deficits. It is most often used in the lumbosacral spine from L1 though S1, and may also be used in the thoracic spine. Excision of tissues compressing the spinal cord (posterior decompression) is a common treatment for patients with herniated or subluxed vertebrae (spondylolisthesis), degenerative intervertebral discs, certain types of vertebral fractures, or spinal tumors. Spinal instability following decompression may be sufficiently severe to require stabilization by bony fusion (arthrodesis) of affected and adjacent vertebrae using implanted autologous bone grafts. Following placement of the graft, sufficient mechanical stability to allow its incorporation may be provided by combinations of various surgically implanted hooks, rods, or wires. However, severe instability may require surgical implantation of plates or rods anchored to vertebral pedicles using screws (pedicle screw fixation systems) in order to provide rigid three-column fixation and minimize the risk of incomplete fusion (psueudoarthrosis or pseudarthrosis) or loss of alignment during fusion. The current medical literature suggests that rigid fixation of the lumbar spine with pedicle screws improves the chances of successful fusion as compared with patients with lumbar spine fusion not supplemented with internal fixation. Internal fusion and fixation are major operative procedures with significant risks and according to the available literature should be reserved for patients with spinal instability associated with neurological deficits, major spinal deformities, spinal fracture, spinal dislocation or complications of tumor. Spinal fusion and pedicle screw fixation has been shown not to be effective for the treatment of isolated chronic back pain, and surgery is not advocated to treat this diagnosis in the absence of instability or neurological deficits. In July 1998, the FDA reclassified into Class II the pedicle screw spinal systems intended to provide immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the treatment of the following acute or chronic instabilities or deformities of the thoracic, lumbar, and sacral spine: degenerative spondylolisthesis with objective evidence of neurological impairment, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and failed previous fusion (pseudarthrosis). Pedicle screw systems intended for any other uses are considered post-amendment Class III devices for which pre-market approval is required.

Intervertebral Body Fusion Devices (Spine Cages)

A spine cage, also known as an interbody cage, is a small hollow cylindrical device, usually made of titanium, with perforated walls. The device is placed in the disc space between two vertebrae to restore lost disc height resulting from a collapsed disc and to relieve pressure on nerve roots. Currently, there are two intervertebral body fusion devices approved by the FDA: the BAK Interbody Fusion System (Spine-Tech, Inc.), and the Ray Threaded Fusion Cage (Surgical Dynamics, a subsidiary of United States Surgical Corporation). The BAK (Bagley and Kuslich) Interbody Fusion System and the Ray Threaded Fusion Cage (TFC) are hollow cylinders made of titanium, which may be implanted by anterior or posterior approach. Unlike pedicle screws, both of these fusion devices are permanent implants, as the literature describes bone growing into and through the implant. The safety and effectiveness of these fusion devices have not been established in three or more levels to be fused, previous fusion attempt at the involved level(s), spondylolisthesis or retrolisthesis of Grade II or greater. Although the BAK has received FDA approval for implantation laparoscopically, studies performed for FDA approval demonstrated significantly greater incidence of complications from anterior spinal reconstructive surgery using a laparoscopic approach than using an open approach. Furthermore, patients with laparoscopically implanted BAK fusion devices were followed for only 6 months; thus, the long-term stability of laparoscopically implanted BAK cages is unknown. Thus, coverage of laparoscopic (endoscopic) implantation of the BAK should be denied as experimental and investigational. (See discussion of anterior endoscopic spinal reconstructive surgery above.)

Vertebroplasty

Percutaneous polymethylmethacrylate vertebroplasty (PPV) is a therapeutic, interventional radiologic procedure, which consists of the injection of a bone cement (usually methyl methacrylate) into a cervical, thoracic or lumbar vertebral body lesion for the relief of pain and the strengthening of bone. This procedure only recently has been introduced, and is being used for patients with lytic lesions due to bone metastases, aggressive hemangiomas, or multiple myeloma, and for patients who have medically intractable debilitating pain resulting from osteoporotic vertebral collapse. Results from two uncontrolled prospective studies and several case series reports, including one with 187 patients, indicate that percutaneous vertebroplasty can produce significant pain relief and increase mobility in 70 percent to 80 percent of patients with osteolytic lesions in the vertebrae. In these reports, pain relief was apparent within one to two days after injection, and persisted for at least several months up to several years. While experimental studies and preliminary clinical results suggest that percutaneous vertebroplasty can also strengthen the vertebral bodies and increase mobility, it remains to be proven whether this procedure can prevent additional fractures in the injected vertebrae. In addition, the duration of effect is not known; there were no long-term follow-up data on most of these patients, and these data may be difficult to obtain and interpret in patients with an underlying malignant process because disease progression may confound evaluation of the treatment effect. Complications were relatively rare, although some studies reported a high incidence of clinically insignificant leakage of bone cement into the paravertebral tissues. In a few cases, the leakage of polymer caused compression of spinal nerve roots or neuralgia. Several instances of pulmonary embolism were also reported. Percutaneous vertebroplasty is an in-patient procedure because it may cause compression of adjacent structures and require emergency decompressive surgery. In addition, radiation therapy or concurrent surgical interventions, such as laminectomy, may also be required in patients with compression of the spinal cord due to ingrowth of a tumor. An assessment of percutaneous vertebroplasty by the National Institute for Clinical Excellence (NICE) (2003) concluded that "current evidence on the safety and efficacy of percutaneous vertebroplasty appears adequate."

Kyphoplasty

Kyphoplasty (also known as balloon-assisted vertebroplasty) is a minimally-invasive orthopedic procedure, which has been developed to restore bone height lost due to painful osteoporotic compression fractures. It involves the insertion of one or two balloon devices into the fractured vertebral body. Once inserted, the surgeon inflates the balloon(s) to create a cavity and to compact the deteriorated bone with the intent to restore vertebral height. The balloon(s) are then removed and the newly created cavity is filled with the surgeon's choice of bone filler material, creating an internal cast for the fractured area.

An assessment of balloon kyphoplasty by the National Institute for Health and Clinical Excellence (NICE, 2006) concluded that "[c]urrent evidence on the safety and efficacy of balloon kyphoplasty for vertebral compression fractures appears adequate to support the use of this procedure provided that normal arrangements are in place for consent, audit and clinical governance." The NICE assessment reviewed three non-randomised studies, two of which compared balloon kyphoplasty with conventional medical care (physical and analgesic therapy) and one which compared the procedure with vertebroplasty. All three studies found that patients who had undergone balloon kyphoplasty had improved pain scores compared with the control group at a maximum follow-up of 24 months. The assessment noted that the specialist advisors to NICE expressed uncertainties about whether the improvements following balloon kyphoplasty (reduced pain and height restoration) are maintained in the long term. In clinical studies, the most common complication following balloon kyphoplasty was cement leakage, occurring in up to 11 percent of patients. Other potential complications of kyphoplasty include infection, allergy, and spinal cord or nerve root injury caused by incorrect needle placement.

Based on the results of an assessment, the Ontario Ministry of Health and Long Term Care (2004) reached the following conclusions about balloon kyphoplasty: "There are currently two methods of cement injection for the treatment of osteoporotic VCFs. These are vertebroplasty and balloon kyphoplasty. Although no RCT has been conducted to compare the two techniques, the existing evidence shows that balloon kyphoplasty is a reasonable alternative to vertebroplasty, given the lower reported peri-operative and long-term complications of balloon kyphoplasty."

Sacroplasty

Sacroplasty is a variation of the vertebroplasty technique, and involves the injection of polymethylmethacrolate cement into sacral insufficiency fractures for stabilization. Sacral insufficiency fractures (SIFs) can cause low back pain in osteoporotic patients. Symptomatic improvement may require up to 12 months. Treatment includes limited weight-bearing and bed rest, oral analgesics, and sacral corsets. Significant mortality and morbidity are associated with pelvic insufficiency fractures. Percutaneous sacroplasty is being developed an alternative treatment for SIF patients.

Frey, et al. (2007) reported on a prospective observational cohort study of the safety and efficacy of sacroplasty in consecutive osteoporotic patients with SIFs. Each procedure was performed under intravenous conscious sedation using fluoroscopy. Two bone trochars were inserted between the sacral foramen and sacroiliac joint through which 2 to 3 mL of polymethylmethacrylate was injected. Thirty-seven patients, 27 females, were treated. Mean age was 76.6 years, and mean symptom duration was 34.4 days. All patients were available at each follow-up interval except 1 patient who died due to unrelated pulmonary disease before the 4-week follow-up. The investigators reported that mean VAS score at baseline was 7.7 and 3.2 within 30 minutes, and 2.1 at 2, 1.7 at 4, 1.3 at 12, 1.0 at 24, and 0.7 at 52 weeks postprocedure. The investigators found that improvement at each interval and overall was statistically significant using the Wilcoxon Rank Sum Test. One case of transient S1 radiculitis was encountered. The investigators concluded that sacroplasty appears to be a safe and effective treatment for painful SIF. Limitations of this study include its small size, limited duration of followup, and lack of control group.

Thermal intradiscal procedures (TIPs)

The evolution of thermal intradiscal procedures (TIPs) involved the use of electrical and radiofrequency energy to apply or create heat within the disc to treat discogenic pain. Percutaneous thermocoagulation intradiscal techniques involve the insertion and heating of a catheter/probe in the disc under fluoroscopic guidance (Urrutia, et al. 2007).  Derby, et al. (2008) stated, “The goals of thermal disc treatments are to remove unwanted tissue such as herniated discs, create a seal to limit expression of matrix components, shrink collagen tissue, and destroy nociceptors.  Although intradiscal heating can be accomplished through a variety of means, including electrocautery, thermal cautery, laser, and radiofrequency energy (RFE), most current intradiscal thermal treatments are performed using RFE.”   A review of the current literature reveals that the mechanism of non-specific chronic low back pain, as well as the mechanism of action of the thermal intradiscal procedures remain uncertain.  There are numerous catheters that have received 510(K) clearance from the FDA for use in thermal procedures.  Some catheters have a specific indication for use in the intervertebral disc and many are indicated for the creation of heat lesions for the relief of pain.

Intradiscal electrothermal annuloplasty (IEA), also called intradiscal electrothermal therapy (IDET), involves the application of high heat using a radiofrequency catheter inserted directly inside the disc.  IDET is used to treat patients with chronic, nonspecific low back pain attributed to degenerative disc disease and who met the criteria for interbody fusion surgery. The IDET technique is commonly identified with the use of the SpineCath Intradiscal catheter.  Original 510(K) clearance was obtained by Oratec Interventions, Inc., Menlo Park, CA.  In 2002 Oratec was acquired by Smith & Nephew. The targeted patients have no clinical or radiologic evidence of significant disc herniation or nerve root compression. The procedure involves placing a thermal catheter within an intervertebral disc via a 17-gauge introducer needle under fluoroscopic guidance and heating the tip to 90°C over 13 minutes and maintaining that temperature for 4 minutes. This thermal therapy is postulated to alleviate discogenic pain by shrinking collagen and denervating nerve endings in the disc annulus. Despite its use at various centers around the country, there are few published clinical studies that assess the efficacy of this procedure. IDET would not directly treat sciatica and is not currently recommended by the manufacturer for patients with sciatica. Proponents believe that IDET works best when the painful disc has not collapsed more than 50 percent.

However, because of the lack of prospective randomized controlled clinical trials with adequate follow up demonstrating the effectiveness of IDET, the procedure is considered experimental and investigational and is not covered. In addition, there are unresolved issues about the long-term effects of this treatment on the biomechanics of the disc. The disc is a viscoelastic structure and possesses various biomechanical properties that are necessary for proper spinal function. The heat of the probe denatures and alters the collagen within the disc, affecting the biomechanics of the disc. The long-term (after 2-5 years) maintenance of good results with IDET is also not known at this point in time. In an editorial accompanying a study reporting on the 2-year outcomes of IDET (Saal & Saal, 2002), Dr. Timothy S. Carey of the University of North Carolina School of Medicine, acknowledged that "patients who undergo IDET do significantly improve over a 2-year period of time." However, because the study did not include a comparison group, "we don't know whether (patients) are doing better or worse than if they would have had another procedure," he told Reuters Health on May 8, 2002. The bottom line, he said, is that more study is needed. "A randomized (comparison) trial is urgently needed before we expose patients to a technique that has not been (rigorously) evaluated," Carey said.

One should note that positive results, similar to IDET, were reported in uncontrolled cohort studies of a similar procedure, percutaneous intradiscal radiofrequency thermocoagulation (PIRFT), also known as percutaneous radiofrequency thermomodulation. However, subsequently performed randomized controlled clinical studies demonstrated that PIRFT had no significant effect compared to placebo (Barendse, et al., 2001).

A randomized controlled clinical study of IDET is currently underway in Australia (Adelaide Spine Clinic, 2001). The developers of this procedure have commented that long-term studies and randomized controlled clinical trials are needed to validate the effectiveness of IDET (Saal & Saal, 1999): "Further study is necessary to define the mechanism and reasons for clinical improvement. Placebo-controlled trials and histologic and biomechanical studies are needed to answer many of the remaining questions. Additional validation of these positive results in placebo-controlled randomized trials and studies that compare IDET with alternative treatments is needed. ... These positive results should be validated in placebo-controlled randomized trials and studies that compare IDET with alternative treatments."

In a patient information statement, the American Academy of Orthopedic Surgeons has commented on the need for prospective randomized controlled studies of IDET (AAOS, March 2002): "The long-term results of this procedure are still unknown. IDET was introduced in 1997 and case series without controls have reported encouraging results. However, these results need to be confirmed in prospective, randomized trials. Additionally, there is debate about how the procedure actually works."

An American Pain Society Bulletin concluded that "[c]learly, IDET is in its infancy and demands the scrutiny of prospective, double-blinded, placebo-controlled studies" (Arends, 2001). In a recent review, Barndes, et al. (2002) commented: "IDET is an innovative tool for the treatment of discogenic back pain. Initial reports suggest that IDET is effective in 60-70% of patients with chronic discogenic low back pain who have not improved with a comprehensive non-operative program. IDET is minimally invasive and has a low complication rate and therefore might offer advantages over surgery. However, the outcomes and cost of IDET have not been compared with those of fusion and chronic pain management. Validation of the initial reports of IDET in placebo-controlled randomized trials is needed."

Technology assessments from several state agencies have also emphasized the need for prospective randomized controlled clinical studies of IDET. A Minnesota Health Technology Advisory Committee Technology Assessment of IDET (2001) concluded: "While the initial data are promising, large randomized controlled trials are needed to determine safety, cost, effectiveness, and long-term outcome. Published research is limited and unrefined due to small sample size, poor study design, and lack of long-term data. Studies comparing IDET with other standard medical and surgical treatments are needed."

A technology assessment by the Institute for Clinical Systems Improvement (2002) concluded as follows: "There is no convincing evidence that shows the short or long-term clinical efficacy of this procedure. Only subjective outcomes from case series and one non-randomized trial have been reported. Blinded, randomized studies comparing the procedure to a placebo treatment or alternative treatments such as spinal fusion have not been done and are needed to develop any conclusion about efficacy of the procedure... The long-term effects of thermal coagulation of the disk are unknown at this time."

The State of Oregon Workman Compensation System (2001) reached similar conclusions regarding IDET: "IDET is a new procedure that is that is currently being promoted by some medical providers as an effective treatment for chronic low back pain. However, there is significant concern that this procedure has not undergone rigorous scientific investigation and therefore is experimental or unproven. There are no randomized studies of its effectiveness, no animal research regarding the long term effects of disc heating, and no evidence of long-term safety."

The Canadian Coordinating Office of Health Technology Assessment (2003) concluded that the available evidence for IDET is of "poor quality" and that "[t]he long-term safety and effectiveness of IDET, and whether patients will require retreatment to maintain pain relief, is not yet known." A structured evidence review conducted by the BlueCross BlueShield Association Technology Evaluation Center (2004) concluded: "The evidence does not permit conclusions as to whether percutaneous intradiscal radiofrequency thermocoagulation for chronic discogenic low back pain improves health outcomes or is as beneficial as established alternatives."

The California Technology Assessment Forum (CTAF) conducted a technology review (2003) of IDET and concluded that IDET with the Radionics Radiofrequency system and with the Oratec IDET system did not meet CTAF technology assessment criteria.

The National Institute for Clinical Excellence (2004) concluded that "[c]urrent evidence on the safety and efficacy of percutaneous intradiscal electrothermal therapy for lower back pain does not appear adequate" and that "[t]he natural history of this condition, the difficulty in assessing pain and the potential for a placebo effect all present problems when interpreting the evidence on this procedure."

At this time, this surgery is only done in the lumbar region. In the early stages of investigation, IDET appears promising; however, additional prospective, randomized controlled clinical studies are needed to compare efficacy against other intradiscal heating procedures, to determine the precise pathology most successfully treated by the procedure, and to assess the long-term outcomes of this procedure as compared to other more conventional therapies.

A Cochrane systematic review (Gibson, 2005) concluded that the effectiveness of IDET remained unproven.

The European Guidelines for the Management of Chronic Nonspecific Low Back Pain (Airaksinen, et al,. 2006) reported that the diagnosis of internal disc distrubtion was surrounded by controversy and that the effect of IDET was not well understood.  The authors summarized the evidence as follows: (i) there is conflicting evidence that procedures aimed at reducing the nociceptive input from painful intervertebral discs using either intradiscal radiofrequency thermocoagulation or IDET, in patients with discogenic low back pain, are not more effective than sham treatments (level C); and (ii) there is limited evidence that radiofrequency lesioning of the ramus communicans is effective in reducing pain up to 4 months after treatment (level C). The authors stated, "We cannot recommend the use of intradiscal radiofrequency, electrothermal coagulation or radiofrequency denervation of the rami communicans for the treatment of either nonspecific or "discogenic" low back pain."

ECRI (2007) determined that the evidence base for IEA for discogenic pain was rated low for quantity, quality, consistency and robustness.  Adverse events for this technology were not well documented.

In a review on IDET for the treatment of chronic discogenic low back pain, Wetzel, et al. (2002) stated that the studies published so far suggest that the pain resulting from lumbar disc disease may be diminished by intradiscal electrothermal annuloplasty. All these studies project a positive therapeutic effect. However, all the studies suffer from the same methodologic flaws. A prospective cohort design or a non-randomized prospective design is used with a biased control. The authors stated that a randomized prospective study is needed. Additionally, more investigation into the basic science of the action of intradiscal electrothermal annuloplasty is required.

Pauza and colleagues (2004) from the East Texas Medical Center presented data from a randomized, double-blind, placebo-controlled trial evaluating the efficacy of IDET for the treatment of chronic discogenic low back pain with 6 month outcomes. The investigators reported significant improvement in the VAS, SF-36 (bodily pain), Beck Depression Scale, Oswestry Low Back Pain Disability Questionnaire. The authors concluded, “Nonspecific factors associated with the procedure account for a proportion of the apparent efficacy of IDET, but its efficacy cannot be attributed wholly to a placebo effect. The results of this trial cannot be generalized to patients who do not fit the strict inclusion criteria.” This is a small, short-term single-institutional study involving the private practice of a single investigator. Because of unanswered questions about the durability of results and generalization of these findings, this single study is not sufficient to draw conclusions about the effect of IDET on health outcomes. 

Freeman, et al. (2005) reported on 57 patients who were randomized to either IDET (n = 38) or sham (n = 19).  The objective of the study was to test the safety of IDET compared with sham treatment for low back pain of at least 3 months duration.  Study participants were chosen from consecutive patients of 3 spine surgeons if they satisfied eligibility criteria.  Randomization occurred after catheter placement via sealed envelope by an independent technician who was responsible to covertly connect the catheter if the patient was to receive active treatment.  All subjects followed a common rehabilitation program.  Patient evaluations occurred at 6 weeks and 6 months by an independent investigator.  Outcomes measures were recorded at baseline and 6 months and included the VAS, low back pain outcome score (LBOS), Oswestry Disability Index (ODI), SF-36, Zung Depression index, the modified somatic perception questionnaire, sitting tolerance, work tolerance, medication, and the presence of any neurologic deficit.  Success was defined a priori as a composite measure: no neurologic deficit resulting from the procedure, an improvement in the LBOS of 7 or more points, and an improvement in the SF-36 subscales of bodily pain and physical functioning of greater than 1 standard deviation from the mean.  Sample size was calculated before the study and using a 2:1 allocation with 80% power, 75 patients were required.  The authors reported that no serious adverse events in either arm of the study occurred, without defining serious adverse events. The authors also reported, “Transient radiculopathy (less than 6 weeks) was reported in 4 study participants who underwent IDET and in 1 study participant who underwent the sham procedure.” The authors concluded that IDET was no more effective than placebo for the treatment of chronic discogenic low back pain.

An assessment of IDET prepared for the Ohio Bureau of Workers' Compensation (2004) concluded that "[t]he more recent medical literature has not found outcomes as good as those previously reported regardless of the measure used in the study" and that "[a]dditional outcomes studies are needed."

Urrutia, et al. (2007) conducted a systematic review of the evidence of percutaneous thermocoagulation intradiscal techniques (IDET and PIRFT), which concluded that "available evidence does not support the efficacy or effectiveness of percutaneous thermocoagulation intradiscal techniquest for the treatment of discogenic low back pain." The investigators reviewed available databases to identify nonrandomized controlled trials and randomized controlled trials on these techniques. The investigators identified six studies that met inclusion criteria, involving a total of 283 patients. Two open, nonrandomized trials (95 patients) showed positive results for IDET compared with rehabilitation and PIRFT. Results from 2 randomized controlled trials showed no differences between PIRFT and placebo, and between different PIRFT techniques. Two randomized controlled trials compared IDET to placebo. One suggested differences only in pain and disability, while the best quality randomized controlled trial showed no differences.

Intradiscal biacuplasty (IDB) (Baylis Medical Inc., Montreal, Canada) is a new minimally invasive transdiscal radiofrequency technique for treatment of back pain. IDB uses two internally water-cooled radiofrequency probes to lesion nociceptors in the intervertebral disc. The bilateral approach is intended to facilitate controlled lesioning between the electrodes in the disc. The Bialys TransDiscal System was cleared by the FDA based on a 510(k) premarket notification. Kapural and Mekhail (2007) reported the treatment of severe axial discogenic pain in a young man using IDB. The investigators reported that there were no intra- and post-operative complications, and significant improvements in patient functional capacity and pain scores were noted. At 6-month follow-up, visual analog scale pain scores decreased from 5 cm to 1 cm, Oswestry disability scores improved from 14 points (28 percent or moderate disability) to 6 points (12 percent or minimal disability) and SF-36-PF (physical function) score changed from 67 to 82. These findings need to be confirmed by well designed controlled clinical studies.  

The Centers for Medicare & Medicaid Services (CMS) has issued a national noncoverage determination for TIPs, after a review of the clinical evidence did not demonstrate that TIPs improved health outcomes. A decision memo on TIPs from the Centers for Medicare & Medicaid Services (2008) concluded, "For TIPs, the mechanisms of action remain theoretical.  A thorough review of the empirical evidence on TIPs is adequate to demonstrate the lack of benefit to health outcomes from these procedures.  Two randomized controlled trials provided evidence of no benefit to health outcomes and one randomized controlled trial failed to demonstrate confidence of any benefit to the Medicare population. The quality of many of the other studies is disappointing and the lack of sufficient documentation of adverse events and long term outcomes is disconcerting. Therefore, we propose that TIPs are not reasonable and necessary."

Epiduroscopy

Epiduroscopy involves insertion of a fiberoptic camera through the sacral hiatus into the lower epidural space, which is then guided upwards towards the lower lumbar discs and nerve roots. Epidural adhesions can be released and anesthetic and steroid injected around nerve roots. In September 1996, the epiduroscope (myeloscope) was cleared by the FDA for visualization of the epidural space. It has been used in the outpatient setting for the diagnosis and treatment of intractable low back pain. Insertion of this miniature fiberoptic scope into the epidural space allows direct visualization of scarring and placement of a catheter through which fluid is injected under pressure to break down scar tissue and lyse adhesions. Although a number of pain treatment centers advertise the availability of this technique and claim it to be successful, there is insufficient scientific evidence in the peer-reviewed medical literature to support the clinical utility of this technique for diagnosis or therapy in patients with spinal pain syndromes, including those with failed back surgery syndromes. Moreover, currently available noninvasive technologies allow adequate visualization of the epidural space to confirm pathology contained therein. An assessment of epiduroscopy for the Australian Safety and Efficacy Register of New Interventional Procedures (ASERNIP-S, 2003) concluded that "[t]here is little high-quality evidence available on the safety and efficacy of epiduroscopically guided surgery/drug delivery... More studies are needed to compare the safety and efficacy of epiduroscopy relative to other procedures." An assessment by the National Institute for Clinical Excellence (NICE, 2004) concluded that "current evidence on the safety and efficacy of endoscopic epidural procedures does not appear adequate for these procedures to be used without special arrangements for consent and for audit or research." The NICE assessment found that "The studies identified were small and uncontrolled. Some measures used in these studies to assess outcomes, such as scores of pain and function, were of unknown validity."

Racz Catheter

The Racz catheter is a small caliber, flexible catheter that is introduced into the sacral hiatus and into the lubrosacral epidural space. The Racz catheter is used to release adhesions deliver steroids and anesthetics into the epidural space. There is no evidence from adequate well-designed randomized controlled clinical trials in the peer-reviewed medical literature supporting the safety and effectiveness of manipulation of an indwelling epidural Racz catheter or epidural injections of hypertonic saline or hyaluronidase to relieve back pain in patients with epidural adhesions, adhesive arachnoiditis, or failed back syndrome from multiple previous surgeries for herniated lumbar disk. The Racz epidural catheter was cleared by the FDA based on a 510(k) premarket notification (PMN) due to FDA's judgment that the device was "substantially equivalent" to devices that were marketed prior to the 1976 Medical Device Amendments to the Food, Drug and Cosmetic Act; thus, the manufacturer was not required to provide the evidence of effectiveness that is necessary to support a premarket approval (PMA) application. Most of the reported studies of the Racz catheter are retrospective (Racz & Holubec, 1989; Manchikanti, et al., 2001; Manchikanti, et al., 1999) or lacking a control group (Racz, et al., 1999). Manchikanti, founder and president of the American Society of Interventional Pain Physicians (ASIPP), is a leading advocate of the use of the Racz catheter (Manchikanti, et al., 1999; Manchikanti & Bakhit, 2000; Manchikanti & Singh, 2002). He is lead author of ASIPP guidelines which incorporate the Racz catheter into the management of chronic spinal pain (Manchikanti, et al., 2003). Manchikanti, et al. (2001, 2004) has reported the results of two controlled clinical studies of the Racz catheter in the ASIPP's official journal Pain Physician. One of these studies involved 45 patients with chronic low back pain, 30 of whom received Racz catheter treatment, and a control group of 15 patients who did not receive Racz catheter treatment. The study was unblinded and utilized a biased control group, as control group subjects were patients who refused Racz catheter treatment, either because coverage was denied by their insurer or for other reasons (Manchikanti, et al., 2001). In another study, subjects with chronic low back pain were randomized to a sham control group or two treatment groups (n = 25 in each group). Nineteen of 25 subjects in the control group were unblinded or lost to follow-up before completion of the 12-month study (Manchikanti, et al., 2004). Both of these controlled clinical studies involve small groups of patients and are from the same group of investigators from a single private practice, raising questions about the generalizability of the findings (Manchikanti, et al., 2001: Manchikanti, et al., 2004). The small sample sizes of these studies do not allow adequate evaluation of potential adverse outcomes that may occur with the procedure (Fibuch, 1999). A Joint Health Technology Assessment of the German Medical Association and the German National Association of Statutory Health Insurance Physicians (KBV, 2003) concluded that, "due to insufficient evaluation and lack of empirical data, at present there is no convincing evidence for the efficacy or effectiveness of the Racz treatment procedure."

Epidural Lysis of Adhesions

The National Institute for Clinical Excellence (NICE, 2004) assessed mobilization and division of epidural adhesions, and concluded that "[c]urrent evidence on the safety and efficacy of endoscopic division of epidural adhesions does not appear adequate for this procedure to be used without special arrangements for consent and for audit or research." The assessment noted that studies of epidural lysis of adhesions are "small and uncontrolled." In addition, NICE noted that "[s]ome measures used in the studies to assess outcomes, such as scores of pain and function, were of unknown validity." NICE stated that the main safety concerns are infection, bleeding, neurological damage, epidural hematoma, and damage to the nerve roots or cauda equina.

Veihelmann et al (2006) examined if epidural neuroplasty is superior to conservative treatment with physiotherapy in treating patients with chronic sciatica with or without low back pain. A total of 99 patients with chronic low back pain were enrolled in this study and randomly assigned into either a group with physiotherapy (n = 52) or a second group undergoing epidural neuroplasty (n = 47). Patients were assessed before and 3, 6, and 12 months after treatment by a blinded investigator. After 3 months, the VAS score for back and leg pain was significantly reduced in the epidural neuroplasty group, and the need for pain medication was reduced in both groups. Furthermore, the VAS for back and leg pain as well as the Oswestry disability score were significantly reduced until 12 months after the procedure in contrast to the group that received conservative treatment. The authors concluded that epidural neuroplasty results in significant alleviation of pain and functional disability in patients with chronic low back pain and sciatica based on disc protrusion/prolapse or failed back surgery on a short-term basis as well as at 12 months of follow-up. Moreover, these investigators stated that further prospective randomized double-blinded studies are needed to prove the effectiveness of epidural neuroplasty in comparison to placebo and in comparison to open discectomy procedures.

Microsurgical Anterior Foraminotomy

Microsurgical anterior foraminotomy has been developed to improve the treatment of intractable cervical radiculopathy. This new technique provides direct anatomical decompression of compressed nerve roots by removing the compressive spondylotic spur or disc fragments through the holes of unilateral anterior foraminotomies. Using microsurgical instruments, the surgical approach exposes the lateral aspect of the spinal column through a small incision at the front of the neck in a naturally occurring crease. The affected nerve root is exposed, and a herniated disc or bone spur is removed to decompress the nerve.  By removing only the herniated portion of the disc, the procedure is intended to preserve normal disc function and avoid bone fusion.   As it utilizes a microsurgical technique that minimizes laminectomy and facet trauma, this technique does not require bone fusion or postoperative immobilization. However, there is a paucity of clinical studies to validate the effectiveness of this approach. The studies reported in the medical literature involve a small number of patients, are published by just one author, and a considerable portion of each article discusses only the technical aspects of the procedure.

Sacroiliac Fusion

Sacroiliac fusion involves bony fusion of the sacroiliac joint for stabilization.  There is insufficient scientific evidence to support use of sacroiliac fusion in treating low back pain due to sacroiliac joint syndrome.

In the 1920's, sacroiliac dysfunction was a common diagnosis and fusion of this joint was the most common form of back surgery. However, there is little evidence that the sacroiliac joint is a common source of back pain. European guidelines on the diagnosis and treatment of pelvic girdle pain (Vleeming, et al., 2004) recommend against the fusion of sacroiliac joints. The guidelines note that severe traumatic cases of pelvic girdle pain can be an exception to this recommendation, but only when other non-operative treatment modalities have failed. In that case, preoperative assessment with an external fixator for three weeks to evaluate longer lasting effects of fixation, is recommended (Wahlheim, 1984; Slätis and Eskola, 1989; Sturesson, et al., 1999). The authors identified no controlled trials of sacroiliac fusion. Available evidence consists of cohort studies (level D evidence) (Smith-Petersen and Rogers, 1926; Gaenslen, 1927; Hagen, 1974; Olerud & Wahlheim, 1984; Waisbrod, et al., 1987; Moore, 1995; Keating, 1995; Belanger and Dall, 2001; Berthelot, et al., 2001; van Zwienen, et al,, 2004; Giannikas, et al., 2004). The guidelines note that, in all reports of fusion surgery, an operation took place only on patients in whom non-operative treatment had been unsuccessful. The cohort studies included from 2 to 77 patients and the results were assessed by the authors as fair to excellent in 50 to 89% of the patients. However, controlled studies are necessary to reach firm conclusions about the effectiveness of this procedure in the treatment of back pain.

Guidelines on treatment of low back pain from the Colorado Department of Labor and Employment (2005) state that sacroiliac joint fusion is of limited use in trauma and is considered to be under investigation for patients with typical mechanical low back pain: "Until the efficacy of this procedure for mechanical low back pain is determined by an independent valid prospective outcome study, this procedure is not recommended for mechanical low back pain."

Endoscopic Diskectomy

There is insufficient evidence from clinical studies proving additional benefits from using an endoscope for performing disc decompression (such as in percutaneous endoscopic diskectomy or endoscopic laser percutaneous diskectomy (LASE)). At this time there are no reliable clinical studies of endoscopic spinal surgery that have included an adequate comparison group of patients receiving open procedures. In addition, there is limited evidence on the long-term outcomes resulting from these endoscopic procedures. Gibson, et al. (2002), reporting on the results of a systematic review of studies on surgery for lumbar disc prolapse, explained that "[t]here is currently no evidence supporting endoscopic... treatment of disc prolapse."

Yeung Endoscope Spine Surgery (Arthroscopic Microdiskectomy, Percutaneous Endoscopic Diskectomy with or without Laser (PELD))

Yeung Endoscopic Spinal Surgery (YESS) (also known as arthroscopic microdiskectomy or percutaneous endoscopic diskectomy (PELD)) is an endoscopic approach to lumbar disc surgery that involves a multichannel scope and special access cannulae that allow spinal probing in a conscious patient, diagnostic endoscopy, and "minimally invasive surgery" (Yeung & Porter, 2002). The Yeung Endoscope Spine System (Y.E.S.S.) (Richard Wolf Surgical Instrument Corp., Vernon Hills, IL) or similar specialized instruments may be used to perform these procedures. The spinal endoscope is used to direct probing and targeted fragmentectomy of disc herniations. In addition, the approach may be used for foraminoplasty, where an endoscope-assisted laser is used to widen the exit route foramina of the lumbar spine and ablate any protruding portions of the intervertebral disk. Typically, procedures are performed at several levels of the spine, either simultaneously or in close temporal succession. Other adjunctive therapeutic procedures may be performed such as applying chemonucleolytic agents, lasers, radiofrequency technology, electrothermal energy, flexible mechanical instruments or intradiscal steroids. Supporters of arthroscopic microdiskectomy state that it provides visualization at the same time as application of therapeutic services. In addition, they argue that the ability to provoke pain while the patient is in the aware state and able to communicate during surgery allows the surgeon to better identify and treat the source of the patient's back pain. However, there is inadequate evidence to determine whether the results of arthroscopic microdiskectomy is as durable or as effective as open spinal surgery. A particular concern is whether this microendoscopic approach allows for adequate visualization of the spine during surgery. Literature to date on arthroscopic microdiskectomy has been limited to review articles and reports of retrospective case series. There are no published prospective, randomized controlled clinical studies of arthroscopic microdiskectomy., and there are no prospective studies with long-term follow up. In addition, the studies of Y.E.S.S. that have been published thus far have been from a single investigator group, raising questions about the generalization of the findings. Thus, arthroscopic microdiskectomy does not meet Aetna's criteria.

Other centers have developed similar approaches; these approaches are not supported by reliable evidence in the peer reviewed published medical literature. These centers typically advertise their "unique" methods of performing endoscopic spine surgery through very small portals using specialized instruments that have been developed by the centers themselves. These procedures are performed while the patient is conscious under moderate sedation. Typically, several surgical procedures are performed at multiple levels simultaneously or on successive days until the patient reports pain relief or surgery is exhausted. Proponents argue that these procedures involve fewer anesthetic risks, a smaller incision, reduced blood loss, faster postoperative recovery and performance of surgery in an outpatient setting.

An important concern about this minimally invasive approach is the limited visualization of the spine, such that the surgeon cannot reliably identify and ensure complete removal all bone spurs and other structures impinging on nerves. In additition, the performance of several surgical procedures in close temporal succession does not allow adequate evaluation of the outcomes of one surgical procedure before subsequent surgical procedures are performed.

One center advertizes that they manufacture special instruments and develop new techniques to perform complex microscopic laser spinal surgeries through portals of 1/4 to 1/2 of an inch under conscious sedation. They state that they have developed "unique" methods of performing endoscopic surgeries.  The center states that they are the only facility that performs endoscopic spinal joint surgery, thoracic laser discectomy, endoscopic sacroiliac joint surgery, endoscopic hardware removal, or endoscopic bio-absorbable fusions or intradiscal stem cell therapy. The center also asserts that their unique minimally invasive spine surgery techniques are so advanced that patients who have failed other minimally invasive or conventional spine surgeries may benefit from their procedures. The center advertises that they have performed over 7000 of these minimally invasive spinal surgeries. Although they state that they regularly publish their findings in peer reviewed journals, what evidence they have published is limited to small, uncontrolled case series focusing with short-term followup (Haufe, et al., 2008; Haufe & Mork, 2007; Haufe & Mork, 2006; Haufe & Mork, 2005; Haufe & Mork, 2004).

Another center makes similar claims for the effectiveness of unique endoscopic laser spinal surgical procedures performed under conscious sedation with patented instruments. The center performs spinal procedures using videoendoscopy and specially adapted surgical probes. Procedures include specialized methods of laser diskectomy, laser lumbar facet debridement, laser foraminoplasty, and laser debridement of spinal processes. The center's website includes testimonials and a list of abstracts presented at meetings, but the center has not published the results of their procedures in peer-reviewed publications. The center recently announced initiation of an outcome study to evaluate outcomes of their procedures in persons with failed back syndrome.

Another center offers unique endoscopic laser methods of performing surgery for back and neck pain. The primary procedures include foraminotomy, laminotomy, percutaneous endoscopic discectomy, and facet thermal ablation. The center advertises the abiltiy to complete all necessary evaluation, preoperative preparation, surgery, and postoperative physical therapy within one week.  The center advertises that advantages of their method of minimally invasvie surgery includes no general anesthesia, no hospitalization, minimally invasive surgery, minimal scar tissue formation, and the availability of outpatient procedures. The center states that the most prominent difference between their techniques and that of other spinal centers is the endoscopic method in which they enter the body to minimize trauma, scar tissue formation, and healing times. The center states that their surgeons have performed approximately ten thousand surgeries collectively for over a decade. Their website includes a testimonials. However, they have not submitted their results for peer-review publication.

Laser diskectomy

Laser diskectomy, or laser-assisted disc decompression (LADD), involves the use of a laser to vaporize a small portion of the nucleus pulposus in order to decompress a herniated disc. In laser diskectomy, the surgeon places a laser through a delivery device that has been directed under radiographic control to the disc, and removes the disc material using the laser. It uses many of the same techniques used in automated percutaneous discectomy.  An endoscope may be used in conjunction with this procedure to visualize the disc space and nucleus pulposus, or the procedure may be done percutaneously. By contrast, percutaneous disc decompression uses an x-ray to localize the tip of the needle/trocar to ensure that it is in the appropriate level and location. The mechanism of action for pain relief in LADD is not well understood; most believe that the primary mechanism of pain reduction after LADD is its decrease in intradiscal pressure. According to the literature, laser-assisted disc decompression appears to be a safe procedure, but studies have not compared it to open surgical alternatives or other percutaneous methods. Randomized controlled trials are needed to compare current standard alternatives to both LADD and conservative treatment. A Cochrane review of surgical procedures for lumbar disc herniation concluded that "[t]here is currently no evidence supporting endoscopic (micro-suction) or laser treatment of disc prolapse" (Gibson, et al., 2002). A systematic review of the literature on percutaneous endoscopic laser discectomy for the Royal Australasian College of Surgeons (Boult, et al., 2000) reached similar conclusions: "Given the extremely low level of evidence available for this procedure it was recommended that the procedure be regarded as experimental until the results are available from a controlled clinical trial, ideally with random allocation to an intervention and control group."

An assessment of laser lumbar diskectomy conducted for the National Institute of Clinical Excellence (NICE, 2003) concluded that current evidence on the safety and efficacy of laser lumbar discectomy does not appear adequate to support the use of this procedure without special arrangements for consent and for audit or research. A systematic evidence review by Jordan, et al. (2003) similarly concluded that the effectiveness of laser diskectomy is "unknown."

Microdiscectomy

Microdiscectomy  refers to temoval of protruding disc material, using an operating microscope to guide surgery. Dent (2001) recently assessed the evidence supporting the use of microdiscectomy for prolapsed intervertebral disc, and found no evidence of differences in clinical outcomes between microdiscectomy and standard open discectomy. A Cochrane review found evidence that microdiscectomy takes longer to perform than standard open discectomy (Gibson, et al., 2002). The review found no evidence of difference in short or long-term symptom relief or complications, or length of inpatient stay. Similarly, a systematic assessment of the literature by Jordan, et al. (2003) concluded that microdiskectomy has not been shown to be more effective than standard diskectomy.

MicroEndoscopic Discectomy

MicroEndoscopic Discectomy (MED) procedure combines conventional lumbar microsurgical techniques with endoscopy and is performed at an outpatient setting. It is employed for the treatment of lumbar spine stenosis and lumbar disc herniation. It has been suggested that MED is less invasive (no damage to muscle, bone or soft tissue) compared with traditional open microdiscectomy. Moreover, MED allegedly allows an early return to work. However, this endoscopic procedure is difficult because of the limited exposure and 2-dimensional video display. The potential injury of the nerve root and prolonged surgical time remain as matters of serious concern. Currently, there is insufficient evidence to support the clinical value of this procedure especially its long-term effectiveness.

Muramatsu, et al. (2001) examined if MED was minimally invasive with respect to the nerve roots, cauda equina, and paravertebral muscles by comparing the post-operative magnetic resonance imaging findings in patients treated by MED and the conventional Love's method. The authors concluded that MED had an effect on the nerve roots and cauda equina that was comparable with that of Love's method. The magnetic resonance images of the route of entry failed to show that MED is appreciably less invasive with respect to the paravertebral muscles. Furthermore, in a review on the various minimally invasive procedures available for the treatment of lumbar disc disease, Maroon (2002) stated that although all percutaneous techniques (including MED) have been reported to yield high success rates, to date no studies have demonstrated any of these to be superior to microsurgical discectomy, which continues to be regarded as the standard with which all other techniques must be compared.

Dynamic Stabilization

Failed back surgery syndrome (FBSS) is reported to occur in 5 to 50 % of cases of lumbar spine operation. A marked rise in the number of performed spinal procedures has also led to an increase in the number of FBSS cases, which is the consequence of biological, psychological, social, and/or economical causes. Patient selection and correct indications are of key importance for successful surgical intervention of this syndrome. Surgical interventions that have been used for FBSS treatment include decompression, stabilization and fusion, as well as dynamic stabilization/neutralization procedures (Chrobok, et al., 2005).

The use of rigid instrumentation in the treatment of degenerative spinal disorders seems to increase the fusion rate of the lumbar spine. However, rigid devices are associated with adverse effects such as pseudoarthrosis and adjacent segment degeneration. The use of semi-rigid and dynamic devices has been advocated to decrease such adverse effects of rigid fixation and thereby to attain a more physiological bony fusion (Korovessis, et al., 2004). Dynamic stabilization systems (e.g., the Dynesys Spinal System) are intended to restrict segmental motion and thus prevent further degeneration of the lumbar spine. The Dynesys, a non-fusion pedicle screw stabilization system (a flexible posterior stabilization system), was developed in an attempt to overcome the inherent disadvantages of rigid instrumentation and fusion. It uses flexible materials threaded through pedicle screws rather than rigid rods or bone grafts alone as an adjunct to fusion. The Dynesys is installed posteriorally, and does not require bone to be taken from the hip, as is required in other fusion procedures. It is designed to prevent over-loading the disc, but it restricts extension and loses lordosis (Sengupta and Mulholland, 2005; Putzier, et al., 2005).

The Dynesys Spinal System (Centerpulse Spine-Tech, Inc., Minneapolis, MN) was cleared by the United States Food and Drug Administration (FDA) via a 510(k) pre-market notification in March 2004. According to the product labeling, it is indicated to provide stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the treatment of the chronic instabilities or deformities of the thoracic, lumbar and sacral spine: degenerative spondylolisthesis with objective evidence or neurological impairment, kyphosis; and failed previous fusion (pseudoarthrosis). In addition, the product labeling states that the Dynesys system is intended for use in persons who meet all of the following criteria:

• Patients who are receiving fusions with autologous graft only; and
• Patients who are having the device attached to the lumbar or sacral spine; and
• Patients who are having the device removed after the development of a solid fusion mass.

Although the Dynesys has been in clinical use for several years, there is insufficient evidence demonstrating that implantation of this device results in improved health outcomes compared to standard treatments.

In a randomized controlled study, Korovessis, et al. (2004) examined the short-term effects of rigid versus semi-rigid and dynamic instrumentation on the global and segmental lumbar spine profile, subjective evaluation of the result, and the associated complications. The study did not examine objective functional outcomes. They compared 3 equal groups of 45 adult patients, who underwent primary decompression and stabilization for symptomatic degenerative lumbar spinal stenosis. Patients were randomly selected and received either the rigid (Group A), or semi-rigid (Group B), or dynamic (Group C) spinal instrumentation with formal decompression and fusion. The mean ages for the 3 groups were 65 +/- 9, 59 +/- 16, and 62 +/- 10 years, respectively. All patients had detailed roentgenographical study including computed tomography (CT) scan and magnetic resonance imaging (MRI) before surgery to the latest follow-up observation. The following roentgenographical parameters were measured and compared in all spines: lumbar lordosis (L1 - S1), total lumbar lordosis (T12 - S1), sacral tilt, distal lordosis (L4 - S1), segmental lordosis, vertebral inclination, and disc index. The SF-36 health survey and visual analog scale (VAS) was used before surgery to the latest evaluation. All patients were evaluated after a mean follow-up of 47 +/- 14 months. Both lumbar and total lordosis correction did not correlate with the number of the levels instrumented in any group. Total lordosis was slightly decreased after surgery (3 %, p < 0.05) in Group C. The segmental lordosis L2 - L3 was increased after surgery by 8.5 % (p < 0.05) in Group C, whereas the segmental lordosis L4 - L5 was significantly decreased in Groups A and C by 9.8 % (p = 0.01) and 16.2 % (p < 0.01), respectively. The disc index L2 - L3 was decreased after surgery in Groups A and C by 17 % (p < 0.05) and 23.5 % (p < 0.05), respectively. The disc index L3 - L4 was increased in Group C by 18.74 % (p < 0.01). After surgery, the disc index L4 - L5 was decreased in all 3 groups: Group A by 21 % (p = 0.01), Group B by 13 % (p < 0.05), and Group C by 13.23 % (p < 0.05). The disc index L5 - S1 was significantly decreased in Group B by 13 % (p < 0.05). The mean pre-operative scores of the SF-36 before surgery were 11, 14, and 13 for Groups C, B, and A, respectively. In the first year after surgery, there was a significant increase of the pre-operative SF-36 scores to 65, 61, and 61 for Groups C, B, and A, respectively, that represents an improvement of 83 %, 77 %, and 79 %, respectively. In the second year after surgery and thereafter, there was a further increase of SF-36 scores of 19 %, 23 %, and 21 % for Groups C, B, and A, respectively. The mean pre-operative scores of VAS for low back pain (LBP) for Groups C, B, and A were 5, 4.5, and 4.3, respectively, and decreased after surgery to 1.9, 1.5, and 1.6, respectively. The mean pre-operative scores of the VAS for leg pain for Groups C, B, and A were 7.6, 7.1, and 6.9, respectively, and decreased after surgery to 2.5, 2.5, and 2.7, respectively. All fusions healed radiologically within the expected time in all three groups without pseudoarthrosis or malunion. Delayed hardware failure (1 screw and 2 rod breakages) without radiological pseudoarthrosis was observed in 2 patients in Group C 1 year and 18 months following surgery. There was no adjacent segment degeneration in any spine until the last evaluation. These investigators concluded that all three instrumentations applied over a short area for symptomatic degenerative spinal stenosis almost equally maintained the pre-operative global and segmental sagittal profile of the lumbosacral spine and was followed by similarly significant improvement of both self-assessment and pain scores. Hardware failure occurred at a low rate following dynamic instrumentation solely without radiologically visible pseudoarthrosis or loss of correction. These researchers further noted that because of the similar clinical and radiological data in all three groups and the relative small number of patients that were included in each group, it is difficult to make any recommendation in favor of any instrumentation.

Putzier, et al. (2005) examined the effect of dynamic stabilization on the progression of segmental degeneration after nucleotomy. A total of 84 patients underwent nucleotomy of the lumbar spine for the treatment of symptomatic disc prolapse. Additional dynamic stabilization (the Dynesys system) was performed in 35 subjects. All patients showed signs of initial disc degeneration (Modic Type I - changes in the vertebral end plate are frequently associated with degenerative disc disease. Type 1 changes include decreased signal intensity on T1-weighted and increased signal intensity on T2-weighted MRI). Evaluation was carried out before surgery, 3 months after surgery, and at follow-up. The mean duration of follow-up was 34 months. Examinations included radiographs, MRI, physical examination, and subjective patient evaluation using Oswestry score and VAS. Clinical symptoms, Oswestry score, and VAS improved significantly in both groups after 3 months. At follow-up, a significant increase in the Oswestry score and in the VAS was seen only in the non-stabilized group. In the dynamically stabilized group, no progression of disc degeneration was noted at follow-up, while radiological signs of accelerated segmental degeneration existed in the solely nucleotomized group. There were no implant-associated complications. These investigators concluded that the Dynesys system is useful to prevent progression of initial degenerative disc disease of lumbar spinal segments following nucleotomy. Moreover, the same group of researchers noted that the Dynesys system seems not to be indicated for treating marked deformities or if osseous decompression needs to be performed (Putzier, et al., 2004).

In contrast to the observation of Korovessis, et al. (2004) and Putzier, et al. (2005), a number of investigators have questioned whether the Dynesys Spinal System offers any clinical advantages over rigid instrumentation (Hopf, et al., 2004; Grob, et al., 2005; Schwarzenbach, et al., 2005).

In a clinical trial, Hopf, et al. (2004) compared the use of artificial disc replacement with dynamic stabilization procedure (Dynesys' method) in the treatment of patients with LBP. Indications for the operation were unsuccessful conservative treatment for over 6 months, segmental pain, age of less than 45 years, evidence of mono- or bi-segmental disc degeneration, with or without disc prolapse, demonstrated by MRI, exclusion of psychogenic disease and positive pre-operative, diagnostic measures such as facet joint infiltration and discography. These investigators stated that in younger patients with mono- or bi-segmental disc degeneration there is an indication for the implantation of an artificial disc. Contraindications for the operation are facet joint arthrosis and age of over 45 years. The investigators commented that the indication in subjects with a classic FBSS is still unclear, the improvement of the instrumentation and a further adaptation of the systems to the known biomechanics of the lumbar spine are mandatory as is an intensive discussion of the operative procedure in the case of revision operations. These authors further noted that the Dynesys' method, with the inherent danger of segmental kyphozitation, a published, significant revision quota combined with a reduction of motility, does not fulfill this criterion.

In a retrospective study, Grob and colleagues (2005) assessed patient-oriented outcome after implantation of the Dynesys Spinal System. A total of 50 consecutive patients instrumented with the Dynesys over the preceding 40 months were invited to complete a postal, patient-oriented follow-up questionnaire. The data from 31 of these subjects (11 men and 20 women; mean age of 50 years), with at least 2 years' follow-up, were analyzed. The primary indication for surgery was degenerative disease (disc/stenosis) with associated "instability"; 11 of 31 (35 %) patients had had prior spinal surgery. One-level instrumentation was performed in 32 % cases, 2-level instrumentation in 52 % cases, 3-level in 13 % cases, and 4-level in 3 % cases. Thirteen of 31 (42 %) patients underwent additional decompression. Within the 2-year follow-up period, 6 of 31 (19 %) patients had needed or were scheduled for another surgical intervention. At follow-up, mean back and leg pain (0 to10 VAS) were 4.7 and 3.8, respectively. The following global outcomes were reported: (i) back symptoms -- 67 % improved, 30 % same, 3 % worse; (ii) leg symptoms - 64 % improved, 21 % same, 14 % worse; (iii) ability to do physical activities/sports - 40 % improved, 33 % same, 27 % worse; (iv) quality of life - 50 % improved, 37 % same, 13 % worse; (v) how much the operation helped - 29 % helped a lot, 23 % helped, 10 % only helped a little, 35 % didn't help, 3 % made things worse. These investigators concluded that their findings indicated that both back and leg pain are, on average, still moderately high 2 years following instrumentation with the Dynesys Spinal System. Only half of the patients declared that the operation had helped and had improved their overall quality of life; less than half reported improvements in functional capacity. The re-operation rate following implantation of the Dynesys was relatively high. The investigators concluded that these results provide no support for the notion that semi-rigid fixation of the lumbar spine resulted in better patient-oriented outcomes than those typical of fusion.

In a recent review on posterior dynamic stabilization systems, Schwarzenbach, et al. (2005) stated that their experience with the Dynesys has shown that this method has limitations in "elderly patients with osteoporotic bone or in patients with a severe segmental macro-instability combined with degenerative spondylolisthesis and advanced disc degeneration. Such cases have an increased risk of failure. Only future randomized evaluations will be able to address the potential reduction of accelerated adjacent segment degeneration. The few posterior dynamic stabilization systems that have had clinical applications so far have produced clinical outcomes comparable with fusion. No severe adverse events caused by these implants have been reported. Long-term follow-up data and controlled prospective randomized studies are not available for most of the cited implants but are essential to prove the safety, efficacy, appropriateness, and economic viability of these methods".

In a review on dynamic stabilization in the surgical management of painful lumbar spinal disorders, Nockels (2005) concluded that posterior dynamic stabilization systems may provide benefit comparable to fusion techniques, but without the elimination of movement. Moreover, the author also noted that further study (well-designed prospective, randomized, controlled trial) is needed to ascertain optimal design and clinical indications.

In a systematic evidence review on non-rigid stabilization procedures for the treatment of LBP, the National Institute for Health and Clinical Excellence (NICE, 2005) stated that "current evidence on the safety of these procedures is unclear and involves a variety of different devices and outcome measures. Therefore, these procedures should not be used without special arrangements for consent and for audit or research". Additionally, the specialist advisors to the Institute's Interventional Procedures Advisory Committee noted that these procedures may be undertaken concurrently with disc decompression or discectomy. Thus, it is difficult to ascertain what clinical benefit is derived from the implants themselves. The specialist advisors noted that the reported adverse events include infection, malpositioned or broken screws leading to nerve root damage, cerebrospinal fluid leak, failure of the bone/implant interface, and failure to control pain. The theoretical risks with the techniques include:device failure (particularly long term), increased lordosis, and root damage caused by loose or misaligned screws.

In summary, despite some preliminary evidence that dynamic stabilization systems (e.g., the Dynesys) have produced clinical outcomes comparable to that of fusion, the clinical value of dynamic stabilization awaits the findings of prospective, randomized, controlled trials, which are an essential requirement for practice of evidence-based medicine.

Inter-Spinous Distraction Procedures

Lumbar spinal stenosis (LSS) refers to narrowing of the lumbar spinal canal, lateral recess, or foramen resulting in neurovascular compression that may lead to pain. Spinal stenosis may be classified by etiology (e.g., congenital or acquired) or symptomatology (e.g., radiculopathy, neurogenic claudication, or mechanical back pain). It can also be classified radiographically, by the location of the stenosis (e.g., central canal, lateral recess, or intervertebral foramen) or by the presence of deformity such as spondylolisthesis or scoliosis. Overlapping in the classification of LSS can occur in that central stenosis with thecal sac compression usually leads to neurogenic claudication, while lateral recess compression is associated with compression of an individual nerve root, thus resulting in radiculopathy. Although symptoms may arise from narrowing of the spinal canal, not all patients with narrowing develop symptoms. The reason why some patients develop symptomatic stenosis and others do not is still unknown. Therefore, LSS doe not refer to the pathoanatomical finding of spinal canal narrowing. It is a clinical syndrome of lower extremity pain caused by mechanical compression on neural elements or their vascular supply (Truumees, 2005).

Non-surgical treatments (e.g., activity modification, medications such as non-steroidal anti-inflammatory drugs, physical therapy that focuses on flexion-based exercises, as well as epidural steroid injections) are usually the first treatment choice for patients suffering from neurogenic intermittent claudication (NIC) secondary to LSS. If symptoms failed to improve with non-surgical treatments, decompressive surgery (e.g., laminectomy, facetectomy, multi-level laminotomies, fenestration, distraction laminoplasty, and microscopic decompression), with or without fusion, may be necessary. Moreover, several studies reported that surgical treatment produces better outcomes than non-surgical treatment in the short-term; however, the results tend to deteriorate with time (Yuan, et al., 2005).

While fusion operations have traditionally been used to manage many disorders of the lumbar spine related to instability, pain, or deformity, concern over the long-term effects of fusion on adjacent spinal segments has led to the development of new approaches such as inter-spinous distraction procedures. The X-Stop Inter-Spinous Process Distraction/Decompression System (St. Francis Medical Technologies, Inc., Alameda, CA) was developed to provide an alternative therapeutic. The principal behind the X-Stop (eXtension-Stop) is that by decompressing the affected spinal segment and maintaining it in a slightly flexed position (and also preventing extension) the symptoms of LSS can be relieved. Additionally, it allows the patient to resume their normal posture rather than flex the entire spine. The X-Stop is made of titanium alloy and is available in five sizes -- 6, 8, 10, 12, and 14 mm in diameter. It consists of two major parts: (i) the universal wing, and (ii) the main body (with oval spacer and tissue expander). The wings prevent anterior and lateral movement while the supraspinous ligament prevents posterior displacement. The oval spacer swivels, making it self-aligning relative to the uneven surface of the spinous process. This ensures that no sharp edges come into contact with the spinous process and that compressive loads are distributed equally on the surface of the bone.

The X-Stop Inter-Spinous Process Distraction/Decompression System gained FDA's pre-market approval (PMA) in November 2005 for use in alleviating the symptoms of patients with LSS. The X-Stop is intended to be used in patients with symptomatic LSS at one or two levels who have failed at least 6 months of conservative treatment. Under local anesthesia, the implant is inserted between the spinous processes of the affected level(s), and prevents extension at those levels. Talwar, et al. (2005) stated that patients with lower bone mineral density must be approached with more caution during insertion of the inter-spinous process implant.

According to SFMT Europe B.V., a subsidiary of St. Francis Medical Technologies, the X-Stop is indicated for any of the following conditions:

• Neurogenic intermittent claudication due to central and/or lateral-recess LSS; or
• Spondylolisthesis up to grade 1.5 (of 4) (about 35 %), with NIC; or
• Baastrup's syndrome (also known as kissing spines); or
• Axial-load induced back pain; or
• Facet syndrome; or
• Degenerative and/or iatrogenic (post-discectomy) disc syndrome; or
• Contained herniated nucleus pulposus; or
• Unloading of disc adjacent to a lumbar fusion procedure, primary or secondary.

There is a scarcity of randomized controlled studies on the clinical value of the X-Stop for the indications listed above, especially its long-term (over 2 years) benefits. Currently, available evidence on this device is mainly from J.F. Zucherman and K.Y. Hsu (developers of this technology), and their associates.

Lindsey, et al. (2003) examined the kinematics of the instrumented lumbar spine and adjacent levels due to the insertion of the X-Stop. Seven lumbar spines (L2 - L5) were tested in flexion-extension, lateral bending, and axial rotation. Images were taken during each test to determine the kinematics of each motion segment. The X-Stop was inserted at the L3 - L4 level, and the test protocol was repeated. These researchers found that the X-Stop does not significantly alter the kinematics of the motion segments adjacent to the instrumented level.

In a study using 7 cadaveric spines (L2 - L5), Fuchs, et al. (2005) noted that the X-Stop may be used in conjunction with a unilateral medial facetectomy or unilateral total facetectomy. However, it should not be used in conjunction with bilateral total facetectomy. In another cadaveric L2 - L5 spine study (n = 7), Wiseman, et al. (2005) reported that inter-spinous process decompression by placing the X-Stop between the L3 - L4 spinous processes will unlikely cause adjacent level facet pain or accelerated facet joint degeneration. Furthermore, pain induced from pressure originating in the facets and/or posterior anulus of the lumbar spine may be relieved by inter-spinous process decompression. Richards, et al. (2005) quantified the effect of the X-Stop on the dimensions of the spinal canal and neural foramina during flexion and extension. By means of a positioning frame, 8 specimens (L2 - L5) were positioned to 15 degrees of flexion and 15 degrees of extension. Each specimen was assessed sing magnetic resonance imaging (MRI), with and without the X-Stop, placed between the L3 - L4 spinous processes. Canal and foramina dimensions were compared between the intact and implanted specimens. These investigators concluded that the X-Stop prevents narrowing of the spinal canal and foramina in extension.

Lee and colleagues (2004) reported their preliminary findings on the use of the X-Stop for LSS in elderly patients (n = 10). Subjects were evaluated post-operatively by MRI and the Swiss Spinal Stenosis Questionnaire. Cross-sectional areas of the dural sac and intervertebral foramina at the stenotic level were measured post-operatively and compared with the pre-operative values. After implantation of the X-Stop, the cross-sectional area of the dural sac increased 16.6 mm2 (22.3 %) and intervertebral foramina increased 22 mm2 (36.5 %). The intervertebral angle as well as the posterior disc height changed significantly. A total of 70 % of the patients stated that they were satisfied with the surgical outcome.

In a multi-center, prospective, randomized, controlled trial, Zucherman and colleagues (2005) compared the outcomes of X-Stop treated NIC patients (n = 100) with their non-operatively treated counterparts (n = 91). The primary outcomes measure was the Zurich Claudication Questionnaire (ZCQ) -- a patient-completed, validated instrument for NIC. At every follow-up visit, X-Stop treated patients had significantly better outcomes in each domain of the ZCQ. At 2 years, the X-Stop treated patients improved by 45.4 % over the mean baseline Symptom Severity score compared with 7.4 % in the control group; the mean improvement in the Physical Function domain was 44.3 % in the X-Stop group and -0.4 % in the control group. In the X-Stop group, 73.1 % patients were satisfied with their treatment compared with 35.9 % of control patients.

Siddiqui, et al. (2007) reported on the one year results of a prospective observational study of the X Stop interspinous implant for the treatment of lumbar spinal stenosis. Forty consecutive patients were enrolled and surgically treated with X Stop implantation. The X Stop device was implanted at the stenotic segment, which was either at 1 or 2 levels in each pateint. Sixteen of 40 patients failed to complete all clinical questionnaires at each of the specified time intervals and were excluded from the study. The investigators reported that, by 12 months after surgery, 54 percent of the 24 remaining patients reported clinically significant improvement in their symptoms, 33 reported clinically significant improvement in their physical function, and 71 percent expressed satisfaction with the procedure. Twenty-nine percent of patients required caudal epidural after 12 months for recurrence of their symptoms of neurogenic claudication.  The investigators noted that, although this study indicates that the X Stop offers significant short-term improvement, these results were less favorable than the previous randomized clinical study. Limitations of this study include the lack of a control group, short duration of follow-up, and high proportion of dropouts.

In a literature review, Christie, et al. (2005) evaluated the mechanisms of action and effectiveness of inter-spinous distraction devices in managing symptomatic lumbar spinal pathology. They stated that these devices continue to be evaluated in clinical trials; and that although the use of inter-spinous implants is still experimental, the early results are promising, and it is likely that future studies will establish a niche for them in the management of lumbar spinal pathology.

Bono and vaccaro (2007) reviewed interspinous process devices for the lumbar spine, and stated that, although some clinical data exist for some of these devices, defining the indications for these minimally invasive procedures will be crucial. "Indications should emerge from thoughtful consideration of data from randomized controlled studies."

Based upon a systematic evidence review on inter-spinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine, the National Institute for Health and Clinical Excellence (NICE, 2006) concluded that "evidence of efficacy is limited and is confined to the medium and short term. These procedures should only be used in the context of special arrangements for consent, audit and research". Additionally, the specialist advisors to the Institute's Interventional Procedures Advisory Committee noted that given the fluctuating symptoms associated with this condition, the assessment of outcomes in clinical studies may be unreliable. Furthermore, some advisors questioned the long-term effectiveness of the procedure.

The questions regarding the long-term effectiveness of the X-Stop raised by Christie, et al. (2005) as well as some specialist advisors of the National Institute for Health and Clinical Excellence's Interventional Procedures Advisory Committee (2006) are congruous with those raised by documents released by the FDA in 2004 prior to a public hearing on the product. The FDA's PMA review stated that "although the device can be inserted with a minimally invasive operative technique as an outpatient procedure with generally a local anesthetic a decision as to the safety and effectiveness of this device is based solely on 24 month data because information on the patient outcomes after 24 months is not available. This information becomes important when looking at pain relief and return to function. Even though the goal of the study was accomplished showing a significant, statistical difference between the investigational and control groups, more patients report improvement at 12 months than at 24 months. Contrary to what has been observed in spinal fusion studies, in this study, a percentage of patients whose symptoms improved at 6 and 12 months show a trend of regression of pain and function symptoms toward baseline levels. There appears to be a trend with early pain relief but the data suggests that in about 15 % of patients initially successfully treated by the X-stop had only temporary relief".

On August 31, 2004, the FDA's Orthopaedic and Rehabilitation Devices Panel voted five to three to recommend a "not approvable" decision on the premarket approval application (PMA) for the X-Stop. The Panel cited concern with the need to identify the patient population that is most likely to benefit from the device, noting that overall effectiveness was not demonstrated in a majority of the clinical study population. The Panel also cited concerns with the longer term effectiveness of the device (longer than two years), with potential bias in the clinical study, and with the need for radiographic or other objective evidence of the device's mechanism of effect on the spine in patients.

As a condition of approval, the FDA has required the manufacturer to conduct a postmarketing study of the long-term safety and effectiveness of the X-Stop in patients who received the X-Stop under the Investigational Device Exemption (IDE). The FDA has required the manufacturer to conduct an additional post-approval study involving 240 patients at up to 8 clinical sites.

Recently published guidelines from the North American Spine Society (2007) concluded that there was insufficient evidence to support the use of the XSTOP in persons with lumbar spinal stenosis. The NASS guidelines noted: "Although the study cited in support of this recommendation is a level I study, it is a single study. Therefore, until futher evidence is published there remains insufficient evidence to make a recommendation [about the use of the XSTOP in lumbar spinal stenosis]".

In summary, the clinical value of X-Stop for patients with LSS is still uncertain. In particular, whether its reported benefit will decline over time will require more research with longer-term evaluation. Additionally, further randomized controlled studies are needed to compare these inter-spinous process implants with traditional surgical interventions such as laminectomy and/or fusion.

Piriformis Muscle Resection

Piriformis syndrome is believed to be a condition in which the piriformis muscle, a narrow muscle located in the buttocks, compresses or irritates the sciatic nerve. There is debate within the medical community whether this is a discrete condition, since it lacks objective evidence, and thus can not be reliably evaluated. Pain associated with piriformis syndrome is exacerbated in prolonged sitting. Specific physical findings are tenderness in the sciatic notch and buttock pain in flexion, adduction, and internal rotation of the hip. Imaging modalities are rarely helpful. Physical therapy is a mainstay of conservative treatment; and is usually enhanced by local injections (Papadopoulos and Khan, 2004). There is insufficient evidence regarding the effectiveness of section of the piriformis muscle as a treatment for piriformis syndrome.

Endoscopic Laser Foraminoplasty

Endoscopic laser foraminoplasty (decompression) is primarily employed to treat patients with back pain caused by a prolapsed intervertebral disc. This endoscope-assisted laser technique is used to widen the lumbar exit route foramina in the spine. A laser is inserted to ablate portions of the intervertebral disc that have protruded.  Hafez and associates (2001) noted that laser ablation of bone and ligament for nerve root decompression using the Ho: YAG laser may offer substantial advantages, but the risk of serious complication may only be avoided if the technique is combined with saline irrigation.

Knight and colleagues (2001) reported that the complication rate of endoscopic laser foraminoplasty is significantly lower than that reported following conventional spinal surgery. From these results, these investigators concluded that endoscopic laser foraminoplasty as a treatment for chronic LBP and sciatica presents less risk to a patient than conventional methods of spinal surgery. On the other hand, the National Institute for Clinical Excellence's (2003) guidance on this procedure stated that current evidence on the safety and effectiveness of endoscopic laser foraminoplasty does not appear adequate to support the use of this procedure without special arrangements for consent and for audit or research. Moreover, the Specialist Advisors believed the effectiveness of this procedure to be unproven; and they also noted a number of potential complications including nerve injury and infection. Takeno, et al. (2006) stated that percutaneous lumbar disc decompression is associated with significant risk of disc, end-plate, and nerve root injuries, contrary to the general belief that the procedure is minimally invasive. Their findings highlight the need for careful diagnosis and sufficient technical skill when selecting percutaneous lumbar disc decompression as a treatment option.

Percutaneous Discectomy

Percutaneous disc decompression is a procedure specifically for a herniated disc in which the core of the disc has not broken through the disc wall. Performed through a needle in the skin, it is a form of surgery in which small bits of disc are removed to relieve pressure on the nerves surrounding the disc. The procedure may be performed with a cutting instrument or laser. Although the literature indicates that open laminectomy is an acceptable and, at times, necessary method of treatment for herniated intervertebral discs, percutaneous discectomy has emerged as a method of treatment for contained and non-migrated sequestered herniated discs. It has taken on two different forms: the selective removal of nucleus pulposus from the herniation site with various manual and automated instruments under endoscopic control (percutaneous nucleotomy with discoscopy, arthroscopic microdiscectomy, percutaneous endoscopic discectomy); the other is the removal of nucleus pulposus from the center of the disc space with one single automated instrument (automated percutaneous lumbar discectomy) to achieve an intradiscal decompression. Automated percutaneous dis