Winged Scapula

Number: 0859

Policy

Aetna considers surgical treatment using a type of dynamic muscle transfer medically necessary for functional impairment related to winged scapula when symptoms do not resolve after 12 months (traumatic cause) to 24 months (non-traumatic cause) of conservative therapy.  Surgical correction for a winged scapula resulting in a cosmetic deformity is considered cosmetic. 

Aetna considers the following experimental and investigational because their effectiveness has not been established:

• Magnetic resonance neurography for evaluation of long thoracic nerve injury
• Neurolysis of the long thoracic nerve or spinal accessory muscle for the treatment of winged scapula
• Polyester tape scapulopexy for scapular stabilization.

See also CPB 0387 - Magnetic Resonance Neurography.

Background

The scapulae or shoulder blades are bony structures on the upper back that connect the upper arms to the thorax. Each scapula is surrounded by thick layers of  muscle that are responsible for the smooth movement of the shoulder joint.  A winged scapula is characterized by protrusion of the medial border of the scapula from the thorax as the scapula rotates out and is caused by paralysis of the anterior serratus muscle.  It is most commonly caused by damage or a contusion to the long thoracic nerve of the shoulder and/or weak-ness of the serratus anterior muscle as a result of blunt trauma to the shoulder, traction of the neck or sometimes from a viral illness.  Scapular winging has be classified as either static or dynamic.  Static winging is attributed to a fixed deformity of the shoulder girdle, spine or ribs and is present when the patient’s arms are at their sides.  Dynamic winging is attributed to a neuromuscular disorder and is produced by active or resisted movement and usually not observed at rest.  Scapular winging has also been classified anatomically based on whether the etiology of the causative lesion is related to nerve, muscle, bone or joint disease.  Scapular winging is the result of neuropraxic injuries in most patients with symptoms spontaneously resolving within 6 to 9 months after traumatic injury and within 2 years after non-traumatic injuries.  Conservative treatment of at least 12 to 24 months has been advocated consisting of pain control, immobili-zation, and rehabilitation.  Localized injections are not routinely used for isolated scapular winging.  A cosmetic deformity may occur in the upper back as the result of winged scapular.

Surgical treatment using a type of dynamic muscle transfer may be indicated for functional impairment related to winged scapula when symptoms do not resolve after 12 months (traumatic cause) to 24 months (non-traumatic cause) of conservative therapy.

Surgical treatment is divided into 2 categories:

• Static stabilization procedures involve scapulothoracic fusion and scapulothoracic arthrodesis in which the scapula is fused to the thorax.  These procedures may be effective in cases of generalized weakness (e.g., facioscapulohumeral muscular dystrophy) when the patient has disabling pain and functional loss and no transferable muscles.  They can relieve shoulder fatigue and pain and allow functional abduction and flexion of the upper extremity.  Static stabilization procedures have fallen out of favor for scapular winging related to isolated muscle weakness because the results deteriorate over time with recurrence of winging.  The usual incidence of complications associated with some of these procedures is high.
• Dynamic muscle transfer procedures have shown better results for correction of scapular winging and restoration of function.  Several different muscles have been used in various muscle transfer techniques to provide dynamic control of the scapula and to improve scapulothoracic and glenohumeral motion.  Transfer of the sternal head of the pectoralis major muscle to the inferior angle of the scapula with fascia lata autograft reinforcement is the preferred method of treatment for scapular winging related to long thoracic nerve injury.  The surgical procedure of choice for scapular winging related to chronic trapezius muscle dysfunction involves the lateral transfer of the insertions of the levator scapulae and the rhomboid major and minor muscles.  This procedure enables the muscles to support the shoulder girdle and to stabilize the scapula.

Surgical procedures for the treatment of winged scapula include:

• Scapulothoracic arthrodesis (fusion)
• Scapulopexy (surgical fixation of the scapula to the chest wall or to the spinous process of the vertebrae)
• Nerve transfer to the serratus anterior muscle
• Eden-Lange procedure or modified Eden-Lange procedure (transfer of the levator scapulae to the acromion and the rhomboid muscles to the infraspinatus fossa). 

Surgical correction for a winged scapula resulting in a cosmetic deformity only would be considered not medically necessary.

Neurolysis is the destruction of nerves to promote analgesia or pain relief.  The spinal accessory nerve is the eleventh cranial nerve.  It emerges from the skull and receives an extra root (or accessory) from the upper part of the spinal cord.  This nerve supplies the sternocleidomastoid and trapezius muscles.  The sternocleidomastoid muscle is in the front of the neck and turns the head while the trapezius muscle moves the scapula, turns the head to the opposite side, and helps pull the head back.  Neurolysis of the spinal accessory muscle for the treatment of winged scapula is investigational/experimental because there is inadequate evidence in the peer-reviewed published clinical literature regarding its effectiveness.

Marie et al (2013) noted that scapular winging secondary to serratus anterior muscle palsy is a rare pathology.  It is usually due to a lesion in the thoracic part of the long thoracic nerve following violent upper-limb stretching with compression on the nerve by the anterior branch of thoraco-dorsal artery at the "crow's foot landmark" where the artery crosses in front of the nerve; scapular winging causes upper-limb pain, fatigability or impotence.  Diagnosis is clinical and management initially conservative.  When functional treatment by physiotherapy fails to bring recovery within 6 months and electromyography (EMG) shows increased distal latencies, neurolysis may be suggested.  Muscle transfer and scapula-thoracic arthrodesis are considered as palliative treatments.  These investigators reported a single-surgeon’s experience of 9 open neurolyses of the thoracic part of the long thoracic nerve in 8 patients.  At 6 months' follow-up, no patients showed continuing signs of winged scapula.  Control EMG showed significant reduction in distal latency; Constant scores showed improvement; and visual analog scale (VAS)-assessed pain was considerably reduced.  Neurolysis would thus seem to be the first-line surgical attitude of choice in case of compression confirmed on EMG. The authors stated that the present results would need to be confirmed in larger studies with longer follow-up, but this is made difficult by the rarity of this pathology.

Polyester Tape Scapulopexy for Scapular Stabilization

Leechavengvongs et al (2015) reported the results of scapular stabilization for winging in patients with chronic upper brachial plexus injury (BPI). A total of 8 patients, mean age of 36 years, who had a winged scapula after successful restoration of major shoulder function by nerve transfer underwent scapular stabilization to the ribcage using polyester tape.  The follow-up period ranged from 24 to 40 months (mean of 38).  Data collection included radiographic analysis, active range of motion (ROM) measurement, University of California Los Angeles shoulder score, and VAS pain score.  All patients had clinical improvement with resolution of scapular winging; 5 patients had no winging and 3 had mild winging after the surgery.  Mean active forward flexion increased from 101° pre-operatively to 127° post-operatively.  Mean active shoulder abduction increased from 91° pre-operatively to 121° post-operatively.  Mean University of California Los Angeles shoulder score improved from 17 to 27 and mean VAS pain score improved from 6.1 to 0.7.  In addition, mean lateral deviated angle increased from 4° from neutral pre-operatively to 9° at the last follow-up.  All patients reported satisfaction with post-operative appearance.  The authors concluded that outcomes of polyester tape scapulopexy in the short- to intermediate-term were favorable in terms of improved appearance, upper extremity function, and pain reduction in patients with winged scapula resulting from chronic upper BPI, and with successful restoration of shoulder motion by previous nerve transfers (Level of Evidence = IV).  This was a small (n = 8) study with short-to-intermediate follow-up (24 to 40 months).  These findings need to be validated by well-designed studies with larger sample size and long-term follow-up.

Magnetic Resonance Neurography

Deshmukh and colleagues (2017) stated that long thoracic nerve (LTN) injury can result in ipsilateral serratus anterior palsy and scapular winging.  Traditional means of evaluating patients with suspected LTN injury include physical examination and electro-diagnostic (EDX) studies.  These researchers described high-resolution magnetic resonance imaging (MRI; MR neurography) findings in patients with clinical suspicion of LTN neuropathy.  In this HIPAA-compliant, institutional review board (IRB)-approved, retrospective study, 2 radiologists reviewed MRI performed for long thoracic neuropathy.  Clinical presentation, EDX studies and MRI of 20 subjects [mean age of 37 ± 13 years; 25 % (5/20) women] were reviewed.  Observers reviewed MRI for LTN signal intensity, size, course, presence or absence of mass and secondary findings (skeletal muscle denervation [serratus anterior, trapezius, rhomboid] and scapular winging).  Descriptive statistics were reported.  Clinical indications included trauma (n = 5), hereditary neuropathy (n = 1), pain (n = 8), winged scapula (n = 6), brachial plexitis (n = 4) and mass (n = 1); EDX testing (n = 7) was positive for serratus anterior denervation in 3 subjects.  Abnormal LTN signal intensity, size, course or mass was present in 0/20.  Secondary findings included skeletal muscle denervation in the serratus anterior in 40 % (8/20), trapezius in 20 % (4/20) and rhomboid in 20 % (4/20).  In 5 % (1/20), an osteochondroma simulated a winged scapula, and in 2/20 (10 %) MRI showed scapular winging.  The authors concluded that high-resolution MRI was limited in its ability to visualize the LTN directly, but did reveal secondary signs that could confirm a clinical suspicion of LTN injury.  This was small (n = 6 for winged scapula) study; its findings need to be validated by well-designed studies.

Maldonado and associates (2017) noted that 2 main hypotheses have been proposed for the pathophysiology of LTN palsy:

1. nerve compression, and
2. nerve inflammation.  

These researchers hypothesized that critical re-interpretation of EDX studies and MRIs of patients with a diagnosis of non-traumatic isolated LTN palsy could provide insight into the pathophysiology and, potentially, the treatment.  These investigators performed a retrospective review of all patients with a diagnosis of non-traumatic isolated LTN palsy and an EDX and brachial plexus or shoulder MRI studies performed at the authors’ institution.  The original EDX studies and MRI were re-interpreted by a neuromuscular neurologist and musculoskeletal radiologist, respectively, both blinded to the hypothesis.  A total of 7 patients met the inclusion criteria as having a non-traumatic isolated LTN palsy.  Upon re-interpretation, all of them were found to have findings not consistent with an isolated LTN.  On physical examination, 3 of them (43 %) presented with weakness in muscles not innervated by the LTN; 4 of them (57 %) had additional EDX abnormalities beyond the distribution of the LTN; 5 of them (71 %) had MRI evidence of enlargement of nerves or denervation atrophy of muscles outside the innervation of the LNT, without evidence of compression of the LTN in the middle scalene muscle.  The authors concluded that in this small series, all 7 patients, originally diagnosed as having an isolated LTN, on re-interpretation, were found to have a more diffuse muscle/nerve involvement pattern, without MRI findings to suggest nerve compression.  These researchers stated that these data strongly supported an inflammatory pathophysiology.

An UpToDate review on "Physical examination of the shoulder" (Simons and Dixon, 2017) does not mention magnetic resonance neurography as a management tool.   Furthermore, an UpToDate review on "Overview of upper extremity peripheral nerve syndromes" (Rutkove, 2017) states that "A number of other isolated focal neuropathies may affect the upper extremity, including suprascapular neuropathy, long thoracic neuropathy, and axillary neuropathy.  These disorders are uncommon.  Suprascapular neuropathy and axillary neuropathies may present with weakness in arm abduction and external rotation; long thoracic neuropathy usually produces winging of the scapula.  Sensory loss and paresthesias occur only with axillary neuropathies.  Pain is usually present in all of these disorders.  Electromyography (EMG) and nerve conduction studies (NCS) identify abnormalities confined to muscles of the affected nerve".

Nerve Grafting

Louis and colleagues (2017) stated that there are very few surgical options available for treating a patient with winged scapula caused by a LTN injury.  Therefore, these researchers devised a novel technique based on a cadaveric dissection whereby regional intercostal nerves (ICN) were harvested and transposed to the adjacent LTN in 10 embalmed cadavers (20 sides).  The LTN was identified along the lateral border of the serratus anterior and ICNs were identified at the mid-axillary line inferior to the lower edge of the pectoralis major muscle.  Along the mid-clavicular line, each ICN was transected and transposed to the adjacent LTN.  The length and diameter of each ICN available for mobilization to the LTN were measured.  All measurements were made with micro-calipers.  Within the operative site, the mean proximal and distal diameters of the LTN were 1.6 and 1.1 mm, respectively.  The adjacent ICN had a mean diameter of 1.3 mm.  On all sides, the ICN branches were easily transposed to the adjacent LTN without any tension.  Anastomosis to the LTN was performed to the 3rd through 6th ICN provided each intercostal was preserved and mobilized anteriorly at least as far as the mid-clavicular line.  The end to end size match between donor and LTN was appropriate on all sides.  The authors found that it was feasible to harvest adjacent ICNs and move these to the adjacent LTN.  They stated that such a procedure, after being confirmed in patients, might offer a new technique for restoring protraction following an LTN injury.

Vetter and associates (2017) noted that several prospective techniques for nerve grafting that may potentially be useful for treatment of winged scapula are emerging based on cadaveric feasibility studies.  One such method involves anastomosis of the accessory nerve with branches of the brachial plexus and the use of the contralateral LTN to re-innervate a paralyzed serratus anterior muscle.  The authors concluded that surgical treatments have evolved over time, from wire fixation and muscle transfers to nerve grafts, each with advantages and common complications.  They stated that the continued use of feasibility studies to investigate relatively new techniques such as nerve grafts may be one of the most significant ways in which medical literature can further contribute to the effective treatment of winged scapula.  These studies could be used in surgical trials in order to identify ideal donors and target nerves for such procedures.

Decompression and Neurolysis of Long Thoracic Nerve

Nath and Somasundaram (2019) noted that in teens, athletes, in general, have been found to have shoulder pain and or winging scapula resulting from long thoracic or spinal accessory nerve injuries.  Accident (fall) and stretch injuries due to over-use and poor sports techniques mainly cause these injuries that affect their upper extremity (UE) movements and functions.  In a retrospective study, these investigators reported a significant improvement in scapula winging and shoulder active ROM in 16 teen patients after long thoracic nerve decompression and neurolysis.  This trial included 16 teen patients who had severe winging scapula and poor shoulder movements and function; they underwent decompression and neurolysis of long thoracic nerve between 2005 and 2016.  The average patient age was 17 years (range of 14 to 19).  These patients had been suffering from paralysis for an average of 15 months (range of 2 to 48).  All patients underwent a pre-operative EMG assessment in addition to clinical evaluation to confirm the long thoracic nerve injury.  Scapula winging was severe in 10 of 16 patients (63 %), moderate in 2 patients (12 %), and mild in 4 patients (25% ).  Mean shoulder abduction (128°) and flexion (138°) were poor pre-operatively.  Shoulder abduction and flexion improved to 180° in 15 patients (94 %) and good (120 °) in 1 patient (6 %) at least 2 months after surgery.  In 11 patients (69 %), the winged scapula was completely corrected post-surgically and it was less prominent in other 5 patients.  The authors concluded that long thoracic nerve decompression and neurolysis significantly improved scapular winging in all 16 teen patients in this study, producing "excellent" shoulder movements in 15 patients (94 %) and "good" result in 1 patient (6 %).  This as a small (n = 16), retrospective study with short-term follow-up (2 months); these findings need to be validated by well-designed studies.

Table: CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":
CPT codes covered if selection criteria are met:
Magnetic resonance neurography - no specific code:
23395	Muscle transfer, any type, shoulder or upper arm; single
23397	multiple
23400	Scapulopexy (eg, Sprengels deformity or for paralysis) [not covered if cosmetic only] [not covered for polyester tape scapulopexy]
CPT codes not covered for indications listed in the CPB:
64708	Neuroplasty, major peripheral nerve, arm or leg, open; other than specified [long thoracic nerve]
+64727	Internal neurolysis, requiring use of operating microscope (List separately in addition to code for neuroplasty) (Neuroplasty includes external neurolysis) [long thoracic nerve]
ICD-10 codes covered if selection criteria are met:
M21.80	Other specified acquired deformities of unspecified limb [winged scapula]
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
G54.0	Brachial plexus disorders [long thoracic nerve]

The above policy is based on the following references: