Discography

Number: 0733

Table Of Contents

Policy
Applicable CPT / HCPCS / ICD-10 Codes
Background
References

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Policy

Scope of Policy

This Clinical Policy Bulletin addresses discography.

1. Medical Necessity

   Aetna considers lumbar provocative discography medically necessary for evaluation for disc pathology in members with persistent, severe low back pain (LBP) and abnormal interspaces on magnetic resonance imaging (MRI), where other diagnostic tests have failed to reveal clear confirmation of a suspected disc as the source of pain, and surgical intervention is being considered.
   
   Note: According to guidelines from the American Association of Neurological Surgeons/Congress of Neurological Surgeons (Resnick et al., 2005), lumbar provocative discography is not recommended as a stand-alone test for treatment decisions in persons with LBP. It should not be attempted in individuals with normal lumbar MRI.

2. Experimental, Investigational, or Unproven

   Aetna considers lumbar provocative discography experimental, investigational, or unproven for all other indications (e.g., lumbosacral radiculopathy and chronic non-specific back pain when criteria above are not met) because its effectiveness for indications other than the ones listed above has not been established.

   The following interventions are considered experimental, investigational, or unproven because the effectiveness of these approaches has not been established:

   1. Cervical and thoracic provocative discography;
   2. Functional anesthetic discography (involving injection of anesthetic directly into the disc);
   3. Contrast disc analysis and mapping.

3. Related Policies

   1. CPB 0016 - Back Pain - Invasive Procedures
   2. CPB 0194 - Spinal Cord Stimulation
   3. CPB 0236 - Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) of the Spine
   4. CPB 0376 - Single Photon Emission Computed Tomography (SPECT)
   5. CPB 0502 - Electrodiagnostic Testing

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Table:

CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
CPT codes covered if selection criteria are met:
62290	Injection procedure for discography, each level; lumbar [not covered for functional anesthetic discography]
72295	Discography, lumbar, radiological supervision and interpretation [not covered for functional anesthetic discography]
CPT codes not covered for indications listed in the CPB:
62291	Injection procedure for discography, each level; cervical or thoracic
72285	Discography, cervical or thoracic, radiological supervision and interpretation
Other HCPCS codes related to the CPB:
Q9951, Q9958 - Q9967	High and low osmolar contrast material
ICD-10 codes covered if selection criteria are met:
M43.06 - M43.07 M43.16 - M43.17	Acquired spondylolisthesis
M46.46 - M46.47 M51.86 - M51.87	Other and unspecified disc disorder, lumbar/lumbosacral region
M47.16	Other spondylosis with myelopathy, lumbar/lumbosacral region
M47.816 - M47.817	Lumbar/lumbosacral spondylosis without myelopathy
M48.061 - M48.07	Spinal stenosis, lumbar/lumbosacral region
M51.06	Intervertebral disc disorder with myelopathy, lumbar region
M51.16 - M51.17 M54.16 - M54.17	Thoracic or lumbosacral neuritis or radiculitis, unspecified
M51.26 - M51.27	Other intervertebral disc displacement, lumbar/lumbosacral region
M51.360 - M51.379	Other intervertebral disc degeneration, lumbar/lumbosacral region
M51.46 - M51.47	Schmorl's nodes, lumbar/lumbosacral region
M54.30 - M54.42	Sciatica
M54.50 - M54.59	Low back pain
M96.1	Postlaminectomy syndrome, not elsewhere classified
S33.100A - S33.141S	Dislocation of lumbar vertebra, open/closed

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Background

Chronic low back pain (LBP) is a common health issue in the United States, with significant economic consequences for the afflicted individuals. Available evidence suggests that the intervertebral disc is one of the most common sources of LBP, accounting for approximately 40% of cases. The pathological basis for discogenic LBP might entail full-thickness radial tears of the annulus fibrosus. While magnetic resonance imaging (MRI) can image the internal morphology of the intervertebral disc, Zhou and Abdi (2006) reported that the relatively low sensitivity (26.7% to 59%) as well as high false-positive (24%) and false-negative (38%) rates decrease the value of MRI in screening for the existence of internal disc disruption as a cause for discogenic LBP. Furthermore, many radiographical abnormalities observed on MRI in patients with LBP are also seen in asymptomatic individuals.

While MRI can detect disc degeneration, it cannot confirm if a disc is symptomatic and responsible for the patient's pain syndrome. Lumbar discography (also known as lumbar provocative discography and provocative lumbar discography) is a test that is used to ascertain if a disc is painful on injection. It is an invasive procedure that entails the injection of radiopaque contrasting materials (1 to 3 ml) into the intervertebral disc, followed by computed tomography (CT) to examine disc abnormalities. Discography can provide a radiographical evaluation of the integrity of the nucleus pulposus and annular rings to determine tears or other lesions that could be the cause of LBP. It can measure disc nociception; a normal disc should not cause pain when injected; however, a disc that is physiologically compromised can mimic the pain experienced by the patient.

Discography is usually carried out when other diagnostic tests have failed to identify the cause of LBP. However, its use is still controversial. Carragee and colleagues (2006) investigated the hypothesis that provocative discography, by strict criteria, accurately identifies an LBP illness due to a primary disc lesion. Over a 5-year period, using a strict enrollment protocol, 32 patients with low LBP and a positive single-level low-pressure provocative discogram underwent spinal fusion. Subjects with known patient selection co-morbidities were excluded. Generic surgical limitations/morbidity were controlled by comparison to the clinical outcomes of a strictly matched cohort of 34 patients having a well-accepted single-level lumbar pathology (unstable spondylolisthesis). Treatment success was compared between groups. In the control spondylolisthesis group, 23 of 32 patients (72%) met the highly effective success criteria compared with 8 of 30 in the presumed discogenic pain cohort (27%). The proportion of patients who met the "minimal acceptable outcome" was 29 of 32 (91%) in the spondylolisthesis group and 13 of 30 (43%) in the presumed discogenic pain group. Adjusting for surgical morbidity and dropout failure, by either criteria of success, the best-case positive predictive value of discography was calculated to be 50% to 60%. The authors concluded that positive discography was not highly predictive in identifying bona fide isolated intradiscal lesions primarily causing chronic serious LBP illness in this first study comparing discography results to a gold standard.

Wichman (2007) stated that lumbar discography has been used to identify the source of LBP when non-invasive imaging (e.g., MRI) does not reveal morphologic abnormalities consistent with symptoms. Controversy regarding the usefulness of discography has been ongoing for over 50 years. Modern advancements in imaging and technique still have not been sufficient to justify the practicality of this procedure for standard use. Based on a review of current literature, pain provoked by discography of normal-appearing discs on MRI was likely due to internal disc disruption, increased pain sensitivity, false positive results with chronic pain, psychological state, central hyperalgesia, and technical difficulty of the procedure. These causes of positive pain provocation are not amenable to invasive treatment. In these cases, an invasive diagnostic procedure to identify problems best treated with conservative management is not practical. The author concluded that there is no clear evidence-based purpose for discography in the diagnosis and treatment of LBP.

On the other hand, there are studies that found discography to be useful in the management of patients with LBP. Yuan and associates (2006) examined the clinical importance of discography and CT after discography (CTD) in lumbar disc diseases and compared CTD with MRI. A total of 265 patients (177 males and 79 females, 298 discs) with back and leg pain underwent discography followed by CT 2 hours later. All discs were classified into 7 types according to the findings by discography and CTD. Comprehensive MRI pictures were available in 237 of the 265 patients (with 257 discs); they accepted the MRI classification and were compared with the CT-discographic findings. A total of 245 patients underwent operation, among which 247 discs showed visual lesions during the procedure, and 238 cases (96.4%) had their disc diseases diagnosed accurately through discography and CTD. Considering the positive screening rate for the discogenic abnormality, the difference was statistically significant between the CTD and MRI groups (p < 0.01). MRI was considered to have limited value in disc diseases with passive discographic findings. These investigators concluded that discography is a safe and effective diagnostic tool, which can gather special information regarding disc abnormalities. The matched-group study showed that MRI and CTD cannot replace each other. MRI may act as the screening tool for disc diseases but is inferior to CTD, especially for the contiguous disc structure in the spinal fixation procedure.

Hao and associates (2006) examined the diagnostic value of lumbar discography in discogenic LBP and the effects of intervertebral fusion surgery. A total of 45 patients with 101 discs underwent discography; 360-degree fusion manipulation was performed on 18 discography abnormal cases, while 27 cases were treated conservatively. Discography, MRI, and provocative pain were observed, and all the cases were followed up. Twenty-one cases showed positive provocative pain (21/45, 47%), and 21 discs of 101 were concordant discography (21/101, 21%). All cases were followed for an average of 16 months (15 to 23 months); the satisfactory rate was 83% (15/18) in the surgery group and 41% (11/27) in the conservative group. The authors concluded that discography is moderately sensitive in the diagnosis of discogenic LBP. Furthermore, the short-term follow-up reveals that the operative group has better pain relief than the conservatively treated group.

Kosharskyy and Rozen (2007) stated that diagnosing discogenic LBP is essential to successful treatment. Traditionally, this should be LBP in a "band-like" distribution without radiculopathy that is worse in the morning, worse with Valsalva, and aggravated by standing in flexion. These researchers noted that provocative discography with manometric monitoring plays an important role in aiding the diagnosis.

1. conclusive,
2. strong,
3. moderate,
4. limited, or
5. indeterminate.

Evidence is strong for the diagnostic accuracy of discography as an imaging tool. Evidence is also strong for the ability of discography to evoke pain. There is strong evidence supporting the role of discography in identifying that subset of patients with lumbar discogenic pain. There is moderate evidence supporting the role of discography in identifying a subset of patients with cervical discogenic pain. There is limited evidence supporting the role of discography in identifying a subset of patients with thoracic discogenic pain. The authors concluded that discography is a useful imaging and pain evaluation tool in identifying a subset of patients with chronic spinal pain secondary to intervertebral disc disorders.

1. evaluation of patients with abnormal discs to help assess the extent of abnormality or correlation of the abnormality with the clinical symptoms, which may include recurrent pain from a previously operated disc and lateral disc herniation,
2. evaluation of patients with persistent, severe symptoms in whom other diagnostic tests have failed to reveal clear confirmation of a suspected disc as the source of pain,
3.  evaluation of patients who have failed surgical intervention to ascertain if there is painful pseudarthrosis or a symptomatic disc in a posteriorly fused segment and to help assess possible recurrent disc herniation,
4.  evaluation of patients before spinal fusion to determine if the lumbar discs within the proposed fusion segment are symptomatic and to ascertain if discs adjacent to this segment are normal, and
5.  evaluation of candidates for minimally invasive surgical intervention to confirm a contained disc herniation or to investigate dye distribution pattern before chemonucleolysis or percutaneous procedures.

The American Association of Neurological Surgeons/Congress of Neurological Surgeons' guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine (Resnick et al., 2005) stated that discography is not recommended as a stand-alone test for treatment decisions in patients with LBP. It should not be attempted in patients with normal lumbar MRI. Discography appears to have a role in the evaluation of patients with LBP, but it is best limited to the evaluation of abnormal interspaces identified on MRI, the investigation of adjacent-level disc disease, and as a means to rule out cases of non-organic pain from surgical consideration.

While discography may play a role in the evaluation of patients with discogenic LBP, its role in cervical and thoracic discogenic pain is not firmly established. Cervical discography has been employed to aid in ascertaining the specific level or levels causing cervical pain and, potentially, which levels to fuse (Zheng et al., 2004; Wieser and Wang, 2007). The American College of Radiology's panel on musculoskeletal imaging for chronic neck pain (Daffner et al., 2005) did not recommend discography for the evaluation of patients with chronic neck pain. Furthermore, the American Society of Interventional Pain Physicians' evidence-based practice guidelines in the management of chronic spinal pain (Boswell et al., 2007) stated that among the diagnostic interventions, the evidence is strong for lumbar discography, whereas the evidence is limited for cervical and thoracic discography.

Although lumbar discography may play a role in evaluating patients with discogenic LBP and aid in selecting patients for surgical intervention, it does not appear to improve surgical outcomes. Madan et al. (2003) reported on their findings of 73 consecutive patients who underwent posterolateral interbody and posterior spinal arthrodesis for discogenic LBP that is refractory to non-operative management. Chronologically, the first 41 patients (group A) were indicated without discography, whereas the remaining 32 patients (group B) had been indicated only if their pain had been reproduced during disc injection. The two groups were similar in demographic, psychometric, and radiological parameters. Average follow-up times for group A and group B were 2.8 years and 2.4 years, respectively, both with a 2-year minimum. Using modified Oswestry scoring, group A and group B patients had satisfactory outcomes of 75.6% and 81.2%, respectively. This difference was neither statistically significant nor suggestive. The authors concluded that pre-operative lumbar discography did not improve surgical outcomes after circumferential fusion for discogenic LBP.

Cohen and associates (2005) provided a clinical overview of lumbar discography and discogenic LBP, with special emphasis on determining the accuracy of discography and whether the procedure improves outcomes for surgery. Based on a large number of comparative studies, plain discography is less accurate than MRI in diagnosing lumbar herniated nucleus pulposus and comparable or slightly more sensitive in detecting degenerative disc disease. For disc degeneration, discography followed by CT remains the gold standard for diagnosis. There are very few studies comparing surgical outcomes between patients who have undergone pre-operative provocative discography and those who have not. What little evidence exists is conflicting. Before disc replacement surgery, approximately half the studies have used pre-operative discography. A comparison of outcomes did not reveal any significant difference between the two groups, but none of the studies was controlled, and they used different outcome measures, follow-up periods, and surgical techniques. The authors concluded that although discography, especially when combined with CT, may be more accurate than other radiological studies in detecting degenerative disc disease, its ability to improve surgical outcomes has yet to be proven.

Willems et al. (2007) assessed whether the pre-operative status of the adjacent discs, as determined by provocative discography, has an impact on the clinical outcome of lumbar fusion in patients with chronic LBP. In 197 patients with an equivocal indication for lumbar fusion (two-thirds were patients with prior spine surgery), the decision for either lumbar fusion or conservative management was determined by a temporary external transpedicular fixation trial. During the diagnostic work-up, all patients had undergone provocative discography that included the assessment of the discs adjacent to the intended fusion levels. The individual changes in pain on a visual analog scale, assessed before treatment and at follow-up, and patient satisfaction were the outcome measures. In the 82 patients who underwent a lumbar fusion, no difference in outcome was found between those patients with degenerative or symptomatic discs adjacent to the fusion and those with normal adjacent discs. The authors concluded that in this cohort study of chronic LBP patients with an uncertain indication for lumbar fusion, the pre-operative status of adjacent levels, as assessed by provocative discography, did not appear to be related to the clinical outcome after fusion.

1. discography was performed by means of a double-needle technique,
2. complications such as discitis were specifically looked for at follow-up, and
3. the exact numbers of patients and those lost to follow-up were reported.

The clinical results of 200 patients with 100% follow-up for a minimum period of 3 months showed no case of discitis. In the literature review, 10 studies were selected. Nine studies without prophylactic antibiotics reported an overall incidence of 12 cases in 4,891 patients (0.25%) or 12,770 discs (0.094%). The only study with prophylactic antibiotics (127 patients) showed no case of discitis. The authors concluded that regarding the small number of patients in the only study in which antibiotics were used and the overall low incidence of post-discography discitis, not enough evidence was found that prophylactic antibiotics can prevent discitis. It was concluded that in lumbar discography by means of a double-needle technique without prophylactic antibiotics, the risk of post-discography discitis is minimal and there is not insufficient evidence to justify the routine use of prophylactic antibiotics.

An assessment by the Centers for Medicare & Medicaid Services (CMS, 2008) has concluded that the effect of discography on clinical outcomes is uncertain. The CMS explained that uncertainty exists in the selection of appropriate patients for the various procedures to treat low back pain that is suspected to be caused by the disc. CMS noted that patient symptoms alone do not accurately point to the disc as the source of pain. The CMS assessment explained that identifying the pain generator in LBP is challenging due to the anatomic complexity of the spine and poor understanding of neurophysiologic mechanisms of pain sensation.

The CMS assessment stated that the literature maintains that for clinicians to identify patients appropriate for back pain procedures, positive provocative discography and either MRI and/or CT indicating intervertebral disc disease (IDD) should be relied on. Citing an assessment by the Danish Centre for Evaluation of Health and Technology (DACETA, 2003), the CMS assessment stated, "[h]owever, the value of discography as a diagnostic tool in the identification of discogenic pain is controversial. The benefit of discography and abnormalities in imaging studies in guiding a patient’s treatment for back pain is questioned." The CMS assessment cited evidence that patients with non-spinal back pain and asymptomatic patients can have positive discography. The CMS assessment also cited evidence that, in patients with LBP, provocation discography can be positive in the absence of imaging structural or physiologic abnormalities. The CMS assessment also cited evidence that showed that, while imaging studies can demonstrate structural and physiologic abnormalities, there is no correlation with either the presence or severity of LBP. The assessment noted that, in fact, patients can have annular tears on MRI or CT and be asymptomatic. The CMS assessment quoted Chou et al. (2005), who stated, "Although a bright, focal increase of T2-weighted magnetic resonance signal in the posterior annulus (the so-called high-intensity zone lesion) is correlated with annular tears, it is not correlated with low back pain." The CMS assessment also found that Slipman et al. (2001) showed no statistical correlation between the side of the patients’ concordantly painful annular tear and the side of the patients’ LBP during discography. The CMS assessment found that these findings directly question if the annular tear, whose natural history is unknown, is the pain generator being tested during discography. The CMS assessment concluded that, "[i]n summary, the effect that discography has on patient outcomes (mediated through the choice of therapy) is uncertain and no specific anatomic lesion has been proven to be the source of discogenic low back pain."

An assessment of provocative discography prepared for the Washington State Health Technology Assessment Program by the ECRI Institute (Schoelles et al., 2007) reached similar conclusions about the lack of reliable evidence of the clinical utility of this test. The assessment concluded that, "[d]ue to the lack of evidence of sufficient quality, we drew no conclusions about whether performing discography influences clinical outcomes." The assessment identified three studies that they judged to be of "low quality" that addressed the prediction of surgical success and outcomes; two of these studies were found to be not favorable. They identified no study that addressed the impact on therapeutic decisions.

The Washington State Health Technology Clinical Committee (HTCC, 2008) found that current evidence does not demonstrate that provocative discography produces reliable results, even though expert opinion evidence supports the use of discography to rule out surgery. The Committee found that the available evidence on specificity is of low quality and focuses on a secondary result of whether the same reader can later read the test in the same way, instead of the more substantive data on whether administering the test at different times produces the same results. The second issue is that the primary outcome relied upon in the test is the replication of normal pain. The Committee observed that there is wide clinical debate on the ability to measure accurately, and the meaning of, the subjective pain response. The relevance is made more unclear by findings that there is no established clinical case definition for degenerative disc disease other than radiographic and other imaging descriptions. The issue of false positives and reliability (percent agreement) are also key concerns raised by several studies, including studies that demonstrated a high rate of positive discography findings in asymptomatic individuals. The Committee noted that patients may be subject to additional tests and risks of invasive therapies unnecessarily. The Committee found that no professional guideline recommends provocative discography as a stand-alone or pre-operative diagnostic test. MRI is recommended as the diagnostic test of choice. The Committee noted that several guidelines do not recommend the use of provocative discography at all, while several advocate its use in addition to other tests.

Carragee et al. (2009) compared the progression of common degenerative findings between lumbar discs injected 10 years earlier with those same disc levels in matched subjects not exposed to discography. A total of 75 subjects without serious LBP underwent a protocol MRI and an L3/4, L4/5, and L5/S1 discography examination in 1997. A matched group was enrolled at the same time and underwent the same protocol MRI examination. Subjects were followed for 10 years. At 7 to 10 years after baseline assessment, eligible discography and controlled subjects underwent another protocol MRI examination. Graders of MRI, blind to group designation, scored both groups for qualitative findings (Pfirrmann grade, herniations, endplate changes, and high-intensity zone). Loss of disc height and loss of disc signal were measured by quantitative methods. Well-matched cohorts, including 50 discography subjects and 52 control subjects, were contacted and met eligibility criteria for follow-up evaluation. In all graded or measured parameters, discs that had been exposed to puncture and injection had greater progression of degenerative findings compared to control (non-injected) discs: progression of disc degeneration, 54 discs (35%) in the discography group compared to 21 (14%) in the control group (p = 0.03); 55 new disc herniations in the discography group compared to 22 in the control group (p = 0.0003). New disc herniations were disproportionately found on the side of the annular puncture (p = 0.0006). The quantitative measures of disc height and disc signal also showed significantly greater loss of disc height (p = 0.05) and signal intensity (p = 0.001) in the discography disc compared to the control disc. The authors concluded that modern discography techniques using a small gauge needle and limited pressurization resulted in accelerated disc degeneration, disc herniation, loss of disc height and signal, and the development of reactive endplate changes compared to matched controls. Careful consideration of risk and benefit should be used in recommending procedures involving disc injection.

A practice guideline from the American Pain Society on LBP (Chou et al., 2009) stated that provocative discography is not recommended for the diagnosis of patients with chronic, non-radicular LBP.

Functional anesthetic discography (FAD) is a new diagnostic procedure that involves the injection of a local anesthetic (e.g., lidocaine or bupivacaine) directly into one or more suspected discs using a balloon-anchored catheter for confirming the presence of injured discs as the source of a patient's LBP. In particular, FAD entails a functional examination; it relies on the patient's induction of pain during active patient movement, which is far different from traditional discography. When the patient performs the movement or position that causes pain, a local anesthetic is then injected into the disc in hopes of alleviating the pain. If the injection relieves the patient's LBP, the disc can be further evaluated for potential treatment. If the injection fails to relieve the patient's LBP, the physician can investigate other possible causes of pain. However, there is insufficient scientific evidence regarding the clinical value of FAD.

In a case-series study, Alamin et al. (2008) presented the findings of three patients in whom FAD was used for the evaluation of presumptive discogenic LBP. In one patient, FAD was confirmatory of the results of provocative discography, while the test results were divergent in the remaining two patients. The authors concluded that further study of FAD will allow more definitive recommendations regarding the validity and utility of this new technique.

In a meta-analysis, Kapoor et al. (2010) estimated the incidence of discitis after cervical discography, delineated the consequences of discitis, and identified factors that may influence this complication. Studies pertaining to cervical discography were identified by a literature review and bibliographic search. These were screened for inclusion in the meta-analysis by two reviewers. Data were collected on a wide range of clinical and demographic variables, including age, gender, morbidities, number of patients, number of discograms, use of prophylactic antibiotics, type of surgical prep, number of needles used, and the number of patients and discs infected. Primary data were used to calculate the incidence of discitis per patient and per disc. A total of 14 studies were included in the analysis. Both procedural details and demographic information on patients were missing from eight studies. The mean age of patients ranged from 41 to 47 years, and gender distribution varied greatly. Antibiotic use was reported in three studies. Cervical discography was complicated by post-procedural discitis in 22 of 14,133 disc injections (0.15%) and 21 of 4,804 patients (0.44%). Only one patient suffered from an infection at more than one spinal level. The authors concluded that the rate of discitis after cervical discography is relatively low. This can perhaps be further decreased by the use of prophylactic intradiscal antibiotics. They stated that should the ability of cervical discography to improve surgical outcomes be proven, the fear of discitis should not preclude the performance of disc provocation.

In a prospective case-series study, Alamin et al. (2011) compared the results of standard pressure-controlled provocative discography (PD) to those of the FAD in a series of patients presenting with chronic LBP and considering surgical treatment. A total of 52 patients presenting with chronic LBP (mean age of 45 years with a range of 24 to 70; 24 men and 28 women; and 25% in a workers' compensation program) were included in this study. Outcome measures included Oswestry, visual analog scale for back pain, distress and risk assessment method psychometric analysis, demographic data, and MRI scan of the lumbar spine. Other outcome measures entailed: during PD – pressurization at pain, pain level, and concordancy; during FAD – position or activity used to elicit typical pain, baseline pain level before injection, during injection, at 5, 10, and 20 minutes after the injection, and substance injected. Standard pressure-controlled PD was performed, followed by (in positive cases or in patients with clinical features and imaging studies felt to be highly suggestive of symptomatic disc degeneration) the FAD test—an assessment of the response to injection of a low dose of local anesthetic into the disc during a position productive of the patient's typical pain. Discordant results of the two tests were noted in 46% of the patients in the series. Of them, 26% of patients with positive PD had negative findings on the FAD test; 16% had positive findings at a single level only, whereas PD had been positive at two or more levels; and 4% had new positive findings on the FAD test. The authors presented the results of a new diagnostic technique in 52 patients with chronic LBP presumed discogenic in origin that was designed to help differentiate between symptomatic and asymptomatic disc degeneration. The findings of the test differed from those of standard pressure-controlled PD in 46% of the cases reported here. They stated that further studies are needed to demonstrate the clinical utility of the test.

The Work Loss Data Institute's clinical practice guideline on "Low back - lumbar & thoracic (acute & chronic)" (2011a) listed FAD as one of the interventions/procedures that was considered but not recommended. Furthermore, the Work Loss Data Institute's clinical practice guideline on "Neck and upper back (acute & chronic)" (2011b) listed discography as one of the interventions/procedures that was considered but not recommended.

Contrast disc analysis and mapping entail the addition of 3-dimensional image post-processing, reconstruction, and/or mapping of data with markers as a method of improving the accuracy and predictive value of discography. However, there is currently a lack of evidence in the peer-reviewed literature to support the improved diagnostic utility of this approach as compared to standard, established provocative discography.

Singh et al. (2012) systematically assessed and updated the quality of clinical studies evaluating the diagnostic accuracy of provocation thoracic discography. A systematic review of the literature was performed to assess the diagnostic accuracy of thoracic discography with respect to chronic, function-limiting thoracic or extra-thoracic pain. The available literature on thoracic discography was reviewed. A methodological quality assessment of included studies was performed using the Quality Appraisal of Reliability Studies (QAREL). The level of evidence was classified as good, fair, and limited (or poor) based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to June 2012, and manual searches of the bibliographies of known primary and review articles. The evidence and clinical value of thoracic provocation discography is limited (poor), with a paucity of evidence, with only two studies meeting inclusion criteria. The authors concluded that based on the available evidence for this systematic review, due to limited evidence, thoracic provocation discography is rarely recommended for the diagnosis of discogenic pain in the thoracic spine if conservative management has failed and facet joint pain has been excluded.

Onyewu et al. (2012) systematically evaluated and updated the diagnostic accuracy of cervical discography. The available literature on cervical discography was reviewed. A methodological quality assessment of included studies was performed using QAREL. Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were utilized for analysis. However, studies scoring less than 50% were presented descriptively and analyzed critically. The level of evidence was classified as good, fair, and limited or poor based on the quality of evidence developed by the USPSTF. Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to June 2012, and manual searches of the bibliographies of known primary and review articles. A total of 41 manuscripts were considered for accuracy and utility of cervical discography in chronic neck pain. There were 23 studies evaluating the accuracy of discography. There were three studies meeting inclusion criteria for assessing the accuracy and prevalence of discography, with a prevalence of 16% to 53%. Based on modified Agency for Healthcare Research and Quality (AHRQ) accuracy evaluation and USPSTF level of evidence criteria, this systematic review indicated that the strength of evidence is limited for the diagnostic accuracy of cervical discography. The authors concluded that there is limited evidence for the diagnostic accuracy of cervical discography. Nevertheless, in the absence of any other means to establish a relationship between pathology and symptoms, cervical provocation discography may be an important evaluation tool in certain contexts to identify a subset of patients with chronic neck pain secondary to intervertebral disc disorders. Based on the current systematic review, cervical provocation discography performed according to the International Association for the Study of Pain (IASP) criteria, with control disc(s) and a minimum provoked pain intensity of 7 out of 10, or at least 70% reproduction of worst pain (i.e., worst spontaneous pain of 7 = 7 x 70% = 5), may be a useful tool for evaluating chronic pain and cervical disc abnormalities in a small proportion of patients. Drawbacks of this study included a paucity of literature, poor methodological quality, and very few studies performed utilizing IASP criteria.

The American Society of Interventional Pain Physicians’ updated evidence-based guidelines for interventional techniques in chronic spinal pain (Manchikanti et al., 2013) stated that "The evidence for diagnostic accuracy for lumbar provocation discography is fair and the evidence for lumbar functional anesthetic discography is limited. The evidence for the diagnostic accuracy of cervical discography is limited. The evidence for thoracic discography is limited."

Furthermore, the American College of Radiology Expert Panel on Musculoskeletal Imaging’s "Appropriateness Criteria® chronic neck pain" (Newman et al., 2013) stated that "X-ray discography was considered but not recommended."

An updated practice guideline on "Chronic pain management" by the American Society of Anesthesiologists Task Force and the American Society of Regional Anesthesia and Pain Medicine (2010) stated that "Provocative discography may be considered for the evaluation of selected patients with suspected discogenic pain. Provocative discography should not be used for the routine evaluation of the patient with chronic non-specific back pain."

The New York State Workers’ Compensation Board’s guidelines on "Mid and low back injury medical treatment" (2013) stated that "Discography, whether performed as a solitary test or when paired with imaging (e.g., MRI), is not recommended for acute, subacute, chronic back pain, or radicular pain syndromes. Improvement in surgical outcomes has not been shown to follow the use of discography, and there is evidence that performing discography on normal discs is associated with an enhanced risk of degenerative changes in those discs in later years."

Ong et al. (2016) noted that open discectomy remains the standard of treatment for patients with lumbar radicular pain secondary to a prolapsed intervertebral disc. Open discectomy performed in patients with small, contained herniations may result in poor outcomes. The various techniques of percutaneous disc decompression (PDD) have been developed to address this population. These investigators performed a literature search on articles that address PDD for lumbar radicular pain. Published techniques include chymopapain chemonucleolysis, percutaneous laser disc decompression (PLDD), automated percutaneous lumbar discectomy (APLD), Dekompressor, nucleoplasty, and targeted disc decompression (TDD). In addition, the rationale of provocative discography, selective nerve root injections, and intra-operative discograms before performing PDD was discussed in detail. Dekompressor and nucleoplasty have the best level of evidence with a score of 2B+. The chymopapain chemonucleolysis has the most publications, but it is also accompanied by the most significant adverse complications and so it is scored as a 2B+/-. The other techniques were supported mainly by observational studies, and thus their scores range between 0 and 2B+/-. There was no supporting evidence for provocative discography in patients with lumbar radicular pain. The evidence for a positive selective nerve root injection as an inclusion criterion or the need for an intra-operative discogram showed mixed results. The authors concluded that nucleoplasty and Dekompressor had a weak positive recommendation for the treatment of patients with lumbar radicular pain. There was no role for provocative discography in this group of patients, although the evidence for a selective nerve root injection or an intra-operative discogram was inconclusive.

Pros

Xi and colleagues (2016) examined the relationship between discogenic pain and disc morphology using discography and CT, respectively, and investigated the effectiveness of this combined method in identifying surgical candidates for lumbar fusion by evaluating outcomes. A total of 43 consecutive patients between 2006 and 2013 who presented with refractory LBP and underwent discography and CT were enrolled in the study; "refractory LBP" was defined as pain symptoms that persisted or worsened after 6 months of non-operative treatments. Concordant pain was defined as discography-provoked LBP of similar character and location with an intensity of greater than or equal to 8/10. Fusion candidates demonstrated positive-level discography and concordant annular tears on CT at no more than two contiguous levels, and at least one negative control disc with an intact annulus. Surgical outcomes were statistically analyzed using the visual analog scale (VAS; 0 = no pain, 10 = worst pain imaginable), Oswestry Disability Index (ODI), and Short Form-36 (SF-36) for back-related pain and disability pre-operatively, and at 2 weeks, 3, 6, 12, and 24 months post-operatively. Annular tears were found in 87 discs. Concordant pain was reported by 9 (20.9%) patients at L3 to L4, 21 (50.0%) at L4 to L5, and 34 (82.9%) at L5 to S1; pain occurred significantly more often in discs with annular tears than those without (p < 0.001). Painless discs were independent of annulus status (p = 0.90); 18 (42%) of the original 43 patients underwent lumbar fusion at L3 to L4 (n = 1 [6%]), L4 to L5 (n = 6 [33%]), L5 to S1 (n = 5 [28%]), and 2-level L4 to S1 (n = 6 [33%]) via a minimally invasive transforaminal lumbar interbody fusion (MITLIF) approach with the aim to replace the nucleus pulposus with bone graft material. The median follow-up time was 18 months (range of 12 to 78 months); VAS, ODI, and SF-36 scores demonstrated significant improvements at 10 out of 12 post-operative time points compared with the pre-operative baseline. The authors concluded that lumbar discography with post-discography CT can be an effective method to evaluate patients with discogenic back pain refractory to non-operative treatments. Those patients with 1- or 2-level high concordant pain scores with associated annular tears and a negative control disc represented good surgical candidates for lumbar interbody spinal fusion.

In a meta-analysis, Fang and co-workers (2017) examined the correlation between the high-intensity zone (HIZ) of a lumbar MRI and discography. These researchers conducted an electronic search of the PubMed, Medline, Embase, and ScienceDirect databases from their respective inceptions to October 2016 using the following search terms: "low back pain," "discogenic low back pain," "HIZ or high-intensity zone," and "discography." Relevant journals and conference proceedings were manually searched; two reviewers independently assessed the quality of the studies, extracted data from the included studies, and analyzed the data. A total of 11 studies were included. The results of the meta-analysis indicated that outstanding relativity and statistically significant correlations were observed between the HIZ and abnormal disc morphology (odds ratio [OR] = 47.79; 95% confidence interval [CI]: 17.07 to 133.77; p < 0.00001), HIZ and pain reproduction (OR = 8.65, 95% CI: 6.01 to 15.23, p < 0.00001), and HIZ and abnormal morphology pain reproduction (OR = 11.74, 95% CI: 1.99 to 69.36, p = 0.007). The authors concluded that the presence of an HIZ on a lumbar MRI T2-weighted image indicated abnormal disc morphology, and there was a strong relationship between the HIZ and pain reproduction. They stated that the HIZ can be an effective index for predicting discogenic LBP.

In a retrospective cohort study, Lee and associates (2017) compared the clinical outcomes of patients undergoing anterior lumbar interbody fusion (ALIF) with or without automated pressure-controlled discography (APCD) before the procedure. Patients (n = 36) who underwent ALIF for lumbar discogenic back pain between 2008 and 2013 and were followed for more than 6 months were enrolled in this study. APCD was performed to identify discogenic back pain. Pre-operative x-rays, CT images, and MRI images were obtained. The intervertebral disc height, type of Modic change, grade of disc degeneration, and fusion rate were determined. Additionally, the presence or absence of HIZ and vacuum disc were checked pre-operatively. Clinical evaluation was performed using VAS, ODI, and SF-36 Health Survey before surgery and every 6 months post-operatively. The average patient age was 53.3 years (range of 31 to 73 years). The mean follow-up duration was 19.7 months; 17 patients (the APCD-ALIF group) underwent ALIF after APCD, and 19 patients underwent ALIF without APCD. The APCD-ALIF group had significantly improved clinical outcomes compared with the control group (VAS score 1.8 ± 1.6 versus 3.3 ± 2.4; p = 0.039; ODI score 6.7 ± 6.3 versus 12.1 ± 6.8; p = 0.019). The surgical improvement rate was significantly associated with the ODI score (p = 0.005). The authors concluded that the findings of this study confirmed that APCD aided surgical outcomes of ALIF in patients with suspected lumbar discogenic pain. They recommend performing APCD before ALIF to confirm lumbar discogenic pain.

Takano and colleagues (2017) noted that posterior epidural migration of lumbar disc fragments (PEMLDF) is extremely rare. It is often confused with other posterior lesions and is usually diagnosed intra-operatively. These investigators described the use of pre-operative discography in the diagnosis of PEMLDF. They presented the case of a 78-year-old man who had acute LBP, gait disturbance, and paresthesia in both legs; MRI showed a mass located posteriorly and laterally to the left aspect of the dural sac at the L3 level. The initial diagnosis indicated PEMLDF, malignancy, spontaneous hematoma, or epidural abscess; L3/4 discography clearly showed leakage of the contrast medium into the posterior dural space, indicating PEMLDF. The lesion was identified intra-operatively as a herniated disc fragment, consistent with the pre-operative discography. The authors concluded that PEMLDF is difficult to diagnose pre-operatively, and discography is useful for the definitive diagnosis of PEMLDF prior to surgery.

Cons

Cuellar and colleagues (2016) stated that provocative discography, an invasive diagnostic procedure involving disc puncture with pressurization, is a test for presumptive discogenic pain in the lumbar spine. The clinical validity of this test is unproven. Data from multiple animal studies confirmed that disc puncture causes early disc degeneration. A recent study identified radiographic disc degeneration on MRI performed 10 years later in human subjects exposed to provocative discography. The clinical effect of this disc degeneration after provocative discography is unknown. In a prospective, 10-year matched cohort study, these researchers examined the effects of lumbar provocative discography on patients subjected to this evaluation method. Subjects (n = 75) without current LBP problems were recruited to participate in a study of provocative discography at the L3 to S1 discs. A closely matched control cohort was simultaneously recruited to undergo a similar evaluation except for discography injections. The primary outcome variables were diagnostic imaging events and lumbar disc surgery events. The secondary outcome variables were serious LBP events, disability events, and medical visits. The discography subjects and control subjects were followed by serial protocol evaluations at 1, 2, 5, and 10 years after enrollment. The lumbar disc surgery events and diagnostic imaging (CT or MRI) events were recorded. In addition, the interval and cumulative lumbar spine events were recorded. Of the 150 subjects enrolled, 71 discography subjects and 72 control subjects completed the baseline evaluation. At the 10-year follow-up, 57 discography and 53 control subjects completed all interval surveillance evaluations. There were 16 lumbar surgeries in the discography group, compared with 4 in the control group. Medical visits, CT/MRI examinations, work loss, and prolonged back pain episodes were all more frequent in the discography group compared with control subjects. The authors concluded that disc puncture and pressurized injection performed during provocative discography could increase the risk of clinical disc problems in exposed patients.

Lipscomb and associates (2017) noted that discography of the intervertebral disk (IVD) may be used to diagnose pathology of the disk and examine if it may be a source of chronic back pain. It has recently been suggested that discography may lead to IVD degeneration, which has been a cause of controversy among spine care physicians. These researchers characterized the changes in stress and displacement of the human lumbar spine disks after puncture due to discography. Both in-vivo experiments using cadaveric specimens and a finite element model of the same L3 to L5 lumbar spine were developed using CT scans. Discography was simulated in the model as an area in the disk affected by needle puncture. The material properties in the nucleus pulposus were adjusted to match experimental data both before and after puncture. Puncture of the IVD resulted in increased deformation and increased stresses in the annulus fibrosis region of the disk. Pressure in the nucleus pulposus was found to decrease after puncture. Experimental and computational results correlated well. The authors concluded that puncturing the IVD changed disk biomechanics and hence may lead to progressive spine degeneration, particularly in the punctured disks.

In a retrospective analysis of prospectively collected data, Staartjes and associates (2018) examined the value of prognostic tests and socio-demographic factors in predicting outcomes following lumbar fusion surgery for degenerative disc disease (DDD). These researchers included patients who underwent fusion surgery for DDD between 2010 and 2016. The outcome measures included pre- and post-operative VAS and ODI scores. Prospectively collected patient data were reviewed for pre-operative tests, peri-operative data, and clinical outcomes. Prognostic tests used were discography, pantaloon cast test (PCT), Modic changes, and a summary of physical symptoms, coined "loading factor." By means of multi-variate step-wise regression, prognostic factors that were useful in predicting outcomes were identified. A total of 91 patients fit the inclusion criteria, with a mean follow-up of 33 ± 16 months. Discography, Modic changes, and loading factor were of no value for predicting outcome scores (p > 0.05). A positive PCT predicted improved outcomes in back pain severity, but only in patients without prior surgery (p = 0.02). Demographic factors that showed a consistent reduction in back pain were female sex (p = 0.021) and no prior surgery at the index level (p = 0.009). No other socio-demographic factors were of predictive value (p > 0.05). The authors concluded that in patients without prior surgery, the PCT appeared to be the most promising prognostic tool. Other prognostic selection tools such as discography and Modic changes yielded disappointing results. In this study, female patients and those without prior spine surgery appeared to be most likely to benefit from fusion surgery for DDD.

Anderson and co-workers (2018) stated that lumbar discography (LD) is used to guide surgical decision-making in patients with DDD. Its safety and diagnostic accuracy are under contention. These investigators evaluated LD's efficacy within the workers' compensation (WC) population. Multi-variate logistic regression analysis was used to determine the impact that undergoing LD before lumbar fusion for DDD had on return-to-work (RTW) rates among 1,407 WC subjects. Discography was negatively associated with RTW status (p = 0.042; OR 0.76); 22.2% (142/641) of LD subjects met the RTW criteria, compared with 29.6% (227/766) of controls. Additional pre-operative risk factors included psychological co-morbidity (p < 0.001; OR 0.34), age greater than 50 (p < 0.005; OR 0.64), male gender (p < 0.037; OR 0.75), chronic opioid use (p < 0.001; OR 0.53), legal representation (p < 0.034; OR 0.72), and fusion technique (p < 0.043). The authors concluded that LD subjects used post-operative narcotics for an average of 123 additional days (p < 0.001); this raised concerns regarding the utility of discography in the WC population.

Manchikanti and colleagues (2018) performed a systematic review of the diagnostic accuracy of lumbar, cervical, and thoracic provocation and analgesic discography literature. These investigators systematically assessed and re-evaluated the diagnostic accuracy of lumbar, cervical, and thoracic discography. The available literature on discography was reviewed. A methodological quality assessment of included studies was performed using the Quality Appraisal of Reliability Studies (QAREL) checklist. Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were included in the analysis. To assess the level of evidence, a modified grading of qualitative evidence criteria was utilized, with grading of evidence into five categories from Level I to Level V incorporating evidence obtained from multiple high-quality diagnostic accuracy studies for Level I and opinion or consensus of a large group of clinicians and/or scientists for Level V. Data sources included relevant literature identified through searches of PubMed and Embase from 1966 to June 2017, and manual searches of the bibliographies of known primary and review articles. Over 100 manuscripts were considered for inclusion. Of these, eight studies met inclusion criteria for diagnostic accuracy and prevalence, with five studies assessing lumbar provocation discography and three studies assessing cervical discography. The results showed variable prevalence from 16.9% to 26% for discogenic pain and 16.9% to 42% for internal disc disruption. The cervical discogenic pain prevalence ranged from 16% to 53%. Based on methodological quality assessment criteria, the strength of evidence for lumbar provocation discography was Level III and for cervical discogenic pain was Level IV. The authors concluded that this systematic review showed that lumbar provocation discography performed according to the International Association for the Study of Pain (IASP) criteria may be a useful tool for evaluating chronic lumbar discogenic pain. The evidence was weaker for cervical and non-existent for thoracic discography. These researchers stated that despite multiple publications in the lumbar spine, the value and validity of discography continue to be debated. Furthermore, in reference to cervical and thoracic discography, the available literature and value and validity continue to be low.

Peng and DePalma (2018) noted that cervical disc degeneration is common in individuals without neck pain. Although MRI may identify a degenerative cervical disc, it will not differentiate a disc that is pathologically painful from one that is physiologically aging. The high prevalence of neck pain and disc abnormalities in asymptomatic individuals provides the conceptual appeal for discography, which is advocated as the only test that connects disease to symptoms, but the procedure remains controversial. The main criticism of cervical discography, as with any other provocation test, is that disc stimulation may provide pain in normal discs.

Provocative Discography: Diagnostic Efficacy and Safety in Symptomatic Degenerative Disk Disease

Pinto et al. (2022) stated that it is reported that the provocative discogram as a diagnostic test for symptomatic degenerative disk disease induces disk degeneration. In a retrospective, cohort analysis, these investigators reported the safety and effectiveness profile of provocative discography. Discogram cases from 1998 to 2011 were identified. A matched control group with no discogram was identified. Both had pre-MRI and post-MRI with 5 years minimum between MRI studies. Statistics were generated by group for each level and for all levels combined. The discogram cohort comprised 53 patients (193 disks). The control group had 51 subjects (255 disks). There were no significant demographic differences between the groups. Time intervals between the index and follow-up MRI were 11 and 8 years for the discogram and control groups, respectively. The most common injected level was L4 to L5; the most painful level was L5 to S1 (VAS = 7.9); the most concordant level was L5 to S1 (75%). The most deranged level as observed on discography was L5 to S1 (98%). Degeneration from normal to abnormal MRI among discogram patients was 60%. For controls, the rate was 33%. The discogram and control cohorts were statistically different (p < 0.01). Among discogram patients, 58% had a fusion surgery between MRI studies. Comparing the discogram group without interval fusion to controls, the degeneration rate was not different at a 5 years' minimum follow-up. The authors concluded that L5 to S1 intervertebral disk level was the most painful, concordant, and deranged level as observed on discogram. Patients who underwent a provocative discogram and interval fusion had a higher rate of subsequent degeneration than similar LBP sufferers with no discogram. Degeneration rates were comparable at 5 years' minimum follow-up between discogram patients without interval spine fusion and patients without discogram exposure. The provocative discogram did not accelerate degeneration among these patients.

Mendez-Gutierrez et al. (2024) stated that here are different techniques and interpretations of discography findings to determine it positive for the diagnosis of discogenic pain. These investigators examined the frequency of use of discography findings for the diagnosis of LBP of discogenic origin. They carried out a systematic review of the literature of the past 17 years in Medline and BIREME. A total of 625 studies were identified, 555 were excluded for duplicates, title and abstract. These researchers obtained 70 full texts of which 36 were included in the analysis after excluding 34 for not meeting the inclusion criteria. Among the criteria in discography to determine it as positive, 8 studies used only the pain response to the procedure, 28 studies used more than 1 criterion during discography to consider it as positive, the evaluation of at least 1 adjacent intervertebral disc with a negative result was necessary in 26 studies to consider a discography as positive. Five studies formally expressed the use of the technique described by Spine Intervention Society (SIS)/IASP to determine a discography as positive. The authors concluded that pain in response to contrast medium injection, assessed with the VAS of 6 or higher, was the most used criterion in the studies included in this review. These investigators stated that although there are already criteria to determine a discography as positive, the use of different techniques and interpretations of discography findings to determine a positive discography for LBP of discogenic origin persists.

Comparison of Magnetic Resonance Spectroscopy and Provocative Discography in the Identification of Chronic Low Back Pain Surgery Candidates

Gornet et al. (2024) stated that verifying lumbar disc pain can present a clinical challenge. Low-pressure provocative discography (PD) has served as the gold standard, although it is invasive and often a challenge to interpret. These investigators reported that magnetic resonance spectroscopy (MRS) biomarkers accurately predict PD results in lumbar discs and improved outcomes for patients with surgery at positive MRS levels versus non-surgery. To further substantiate MRS for diagnosing painful discs, these researchers reported a prospective comparison of two MRS-derived measures: NOCISCORE (pain) and SI-SCORE (degeneration severity). Lumbar MRS and software-based post-processing (NOCISCAN-LS) were performed in 44 discs in 14 patients (prospective cohort [PC]). PC data were compared to prior data used to establish the NOCISCORE (training cohort [TC]). The NOCISCORE was converted to an ordinal value (high/intermediate/low; NOCI+/mild/-) and compared against painful (P) versus non-painful (NP) control diagnosis (PD) for 19 discs where PD was performed in the PC (12 NP; 7 P). Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated. The SI-SCORE was compared against MRI Pfirrmann Grades for 465 discs in 126 patients (PC plus TC). For the PC, MRS (NOCI+/-) compared to PD (P/NP) showed an accuracy of 87% and sensitivity and specificity of 100%. The PPV and NPV of MRS were 100%. NOCISCOREs were significantly higher for PD+ versus PD- discs for PC and TC (p < 0.05), and the NOCISCORE distributions for PD+/- groups were not statistically different between the PC and TC (p > 0.05). SI-SCORES differed between Pfirrmann Grades 1 and 2 (less degenerated) versus Grades 3 and 4 (more degenerated; p < 0.05), with a progressively decreasing trend from Pfirrmann Grades 1 to 5. The authors concluded that the findings of this study provided prospective confirmation of the predictive value of disc MRS for distinguishing painful discs and for assessing disc structural integrity.

These researchers stated that one drawback of this trial was the small sample size of discs and respective patients evaluated in the PC group as a validation of the disc MRS approach as previously trained in the TC group for the study. However, despite the relatively small sample sizes, they were sufficient to reveal certain observations of statistical significance, such as the significantly higher NOCISCOREs for PD+ versus PD− controls in the PC group (and non-significant differences of those NOCISCOREs between the PC and TC groups). Another drawback of this study was that successful MRS execution may not be feasible on some spinal levels. As discs degenerate, they dehydrate and lose height, potentially degrading the quality of the MRS signal. Presently, MRS voxel heights are limited to a minimum of 3 mm, which may prevent successful data acquisition from severely degenerated discs; however, this aspect does not meaningfully limit clinical utility in most situations since MRS information is combined with other clinical data when making treatment choices. For example, traditional clinical examination and other radiographic features may indicate that severely degenerated discs are indicative of fusion surgery. Alternatively, severely degenerated discs are not suited for biological therapies and may be excluded using routine clinical imaging. The unique value that MRS provides is that it reduces ambiguity when making treatment decisions for discs that are not severely degenerated and where routine clinical imaging provides insufficient actionable information. Moreover, these investigators stated that future studies are being planned to further examine the NOCISCAN-LS disc MRS approach prospectively in more patients and to investigate additional disc MRS applications in the cervical and thoracic spines and develop algorithms that optimally combine MRS with other clinical data that capture the multi-dimensional aspects of pain within individual discogenic LBP patients. These researchers also anticipate future use of this MRS tool for other purposes, such as screening for infection, tracking the success of biological therapies meant for disc repair, as well as studying biochemical mechanisms of action for such new therapies.

Wilson et al. (2025) noted that chronic low back pain (CLBP) is a significant US healthcare burden with millions of lumbar spine procedures every year. Diagnostic tests are crucial in guiding treatment; however, PD, the most common diagnostic procedure, lacks robust evidence of its value. A non-invasive alternative using MRS offers a potential solution. In a cost-effectiveness modeling study, these researchers examined the cost-effectiveness of MRS with the NOCISCAN diagnostic algorithm compared to PD for identifying lumbar discs requiring surgical intervention. They used data from a clinical study of 139 CLBP patients who met criteria for and received PD of the lumbar spine and presented with an Oswestry Disability Index (ODI) score of 40 or higher, comparing PD and MRS-based diagnostics. These investigators considered diagnostic costs, adverse events (AEs), surgical costs, as well as outcomes based on a 15-point improvement on the ODI. Incremental cost-effectiveness ratios (ICERS) and probabilistic sensitivity analyses were determined. The mean total cost per PD patient was $59,711, and $57,998 for MRS, demonstrating a $1,712 cost savings per MRS diagnosed patient. Diagnostic costs ($1,950 for PD; $1,450 for MRS) saved $500 per MRS patient. PD incurred AE costs ($57,323) for 1% of patients, which MRS eliminated. MRS-based diagnosis showed 78% surgical success, whereas PD achieved 68%. MRS was the dominant diagnostic strategy, with better clinical outcomes and cost savings. Probabilistic sensitivity analysis confirmed MRS dominance and was cost-effective across a wide range of willingness-to-pay thresholds and across two different scenarios that varied base-case outcomes and surgical rates. The authors concluded that this study showed cost-effectiveness dominance of MRS with the NOCISCAN diagnostic algorithm over PD for identifying CLBP surgical candidates. These researchers stated that MRS provided significant cost savings and resulted in better surgical outcomes, making it a preferred choice for insurers and health systems.

These researchers stated that the availability of comparative data for diagnostics was low; however, they were fortunate to have robust comparison data upon which they based this cost-effectiveness analysis (CEA). These investigators noted that there are several limitations inherent in this CEA model, mainly for the outcomes of PD-negative and non-surgical patients. The authors employed other non-comparative literature-based data as a basis for the sensitivity and specificity of the PD approach for these outcomes. Furthermore, they did not have comparative data for MRS-negative and non-surgical patients; thus, they used literature-based results of PD-negative patients without surgery. To account for the differences in these results that were not directly comparative, these investigators also tested additional scenarios where they equalized these uncertainties. MRS was still the more cost-effective option. Although most outcomes were based on ODI improvement, for a small number of patients (MRS-negatives and PD-negatives not having surgery), it was unclear what exact measurement of success was used, which could be important. This analysis addressed these drawbacks by equalizing the outcomes of these groups for MRS and PD, still showing the cost-effectiveness of the MRS approach. Another limitation of this study was that these researchers did not conduct trial endpoints past the outcome of ODI success to include life expectancy, so they could compare their CEA with a willingness-to-pay (WTP) threshold using quality-adjusted life years saved (QALYs). These investigators thought it was inappropriate to extend estimates to survival for a diagnostic test without more evidence. Because of the dominance shown for MRS compared to PD, this was still a strong conclusion for their analysis. In addition, many researchers and countries using CEA data as evidence for drug/device approvals have begun to move away from a strict QALYs metric of value for dollar, as it is unable to sufficiently capture societal benefits. The authors stated that historically there are few cost-effectiveness studies comparing diagnostics for back pain, and none comparing the use of MRI or discography for identification of discs needing surgical intervention. This is because there is less evidence on the pricing and reimbursement policies of diagnostics and more limited information for market entry of diagnostic modalities and a lack of a “gold standard” for diagnostic comparison at approval, thus limiting the evidence needed for robust economic evaluations.

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References