Evaluation and Management of Scapular Winging due to spinal accessory nerve palsy

The Problem

Palsy of the eleventh cranial nerve, the spinal accessory nerve (SAN), is a rare cause of scapular winging, leading to a painful disability about the upper extremity. There are often subtle differences that allow it to be differentiated from other etiologies of scapular winging, although at times clinical examination alone cannot detect the cause of winging and further tests are needed. Patients with this condition are often subject to incorrect and unnecessary surgeries. This type of winging is sometimes referred to as lateral winging as there is lateral displacement of the scapula without the medial pull of the trapezius. Causes for this condition can be traumatic or even iatrogenic following previous surgery. Like most nerve injuries, recovery can occur even after a significant period of time and non-operative therapy is the mainstay of early treatment with some exceptions. If, however, the nerve does not recover, strengthening of the remaining scapular musculature cannot compensate for the loss of the trapezius and surgery is often indicated.

Clinical Presentation

Unlike injury to the long thoracic nerve (LTN) which is usually idiopathic, injury to the SAN commonly follows neck surgery such as lymph node biopsy or mass excision. Injury can occur where the nerve crosses the posterior cervical triangle. Other causes such as trauma or viral illness can also be responsible. Due to this reason, the age of presenting patients can be scattered throughout adulthood, anywhere from 2nd – 8th decade. Patients complain of a dull pain from their shoulder radiating down their arm and complain of the asymmetry about their shoulders (Figure 1). The winging often makes it uncomfortable to sit against hard surfaces and they may notice their shoulder drooping downward. There can be marked weakness and secondary conditions such as impingement, adhesive capsulitis, thoracic outlet syndrome or traction palsies to the brachial plexus can often be present.

Diagnostic Workup

Examination begins with the neck and an asymmetric neckline is often present due to the atrophy of the trapezius and the obvious drooping of the shoulder. Male and female patients need to be in appropriate gowning to allow full visualization of the shoulders and scapula to detect this. With forward elevation, the scapula displaces laterally, rotating downward and outward. The shrug test should be performed against resistance as the levator scapulae can often provide a normal shrug against gravity. Active and passive range of motion (ROM) should be tested and secondary processes such as impingement or instability should be sought out. A complete neurologic examination of the extremity should also be performed.

Plain films are obtained, although they are usually normal. If there is any concern for a mass lesion of the scapula, then three-dimensional imaging should be performed.

An EMG evaluation is needed to confirm the diagnosis and also evaluate the status of other nerves, such as the LTN. EMG testing should be deferred in the case of an acute injury until at least 6 weeks after the onset of symptoms with few exceptions.

Non–Operative Management

As with all nerve injuries, the chance of recovery is linked to the extent of injury to the nerve. Traction neuropraxias are expected to recover, but can take up to a year to do so. In the case of an acute injury after a surgical exploration in which the nerve may have been iatrogenically severed, early exploration with possible nerve grafting is advisable and a course of non-operative therapy is not recommended. Conservative treatment with rehabilitation is largely unsuccessful as the remaining musculature cannot substitute for the area or the vector of pull of the trapezius.

Indications for Surgery

There is considerable debate regarding management of acute, identified iatrogenic injuries. Some authors recommend acute exploration with neurolysis versus repair of the nerve and state that this remains a viable option even up to 29 months after the injury. Other authors have found that the window of time available for a nerve repair is less than 20 months. Of note, the nerve does not have to travel a great distance from the usual site of injury (posterior cervical triangle) to the motor-end-plate, so delayed repair can still be a viable option as opposed to other nerves.

Unfortunately, it is common for these patients to present to the orthopaedic surgeon greatly delayed from the initial injury, even many years later. In that setting, most surgeons would agree that a tendon transfer is the only realistic surgical option. In that scenario, surgery is indicated for those with documented SAN palsy on EMG and no injury to the dorsal scapular nerve or long thoracic nerve as the planned procedure relies on those nerves functioning post-operatively. Patients who did not have an acute iatrogenic injury to the nerve should have failed non-operative therapy and be motivated and healthy enough to participate in the necessary post-operative care. This is important as injury to the SAN can often occur in resections for malignant neck lesions in patients who would not be healthy enough to undergo surgery.

Surgical Technique

Surgery to address trapezius palsy consists of a transfer of the levator scapulae and the rhomboids; this is a modification of the Eden-Lange procedure. Our modification was elucidated by Dr Bassem Elhassan (unpublished) of the Mayo Clinic to better reproduce the vectors of pull of the three portions of the trapezius muscle: descending, transverse and ascending portion.

Necessary equipment/Instrumentation:

Long bean bag for lateral position

Pneumatic arm positioner

Oscillating saw

Motorized burr

Set up:

The patient is placed in a supine position for routine initiation of general anesthesia and then moved to the lateral position with the use of a long bean bag to support the body (Figure 2). An axillary roll is placed and all other potential sites of pressure are padded including the knees and genitals. A pneumatic arm holder is placed on the opposite side of the bed to support and position the arm. The contralateral arm is either tucked at the side or placed in a comfortable position above the head.

Figure 2.

The entire arm and hemithorax is then prepped and draped and an antibiotic-impregnated adhesive drape is used to cover all exposed skin. Surface anatomy of spinous processes as well as the medial border and spine of the scapula is marked out and local anesthetic with epinephrine is injected in planned incision sites to aid in hemostasis. Preoperative antibiotics are given.

Harvesting rhomboids/levator:

The incision is made along the medial border of the scapula with sharp dissection down to the trapezial fascia. The trapezius will be a thin, atrophic layer and missed if careful dissection is not performed. The trapezius is then separated from the underlying rhomboids, which it may be adhered to. The arm is positioned to place the rhomboids under tension to develop the interval underneath the rhomboid major and define the rhomboid minor as well as the levator scapulae. As each muscle is defined, a Penrose drain is placed around it (Figure 3). The infraspinatus is then dissected off the medial border of the scapula.

Figure 3.

A small oscillating saw is then used to harvest a wafer of bone incorporating the insertion site of the rhomboid major. The muscle is then mobilized from the underlying muscles. The dissection must stay lateral, and not more than 2cm medial to the scapular boarder in order to avoid injury to the dorsal scapular nerve. If the serratus anterior is violated during this dissection, it is repaired back to its insertion through drill holes.

The rhomboid minor and levator scapulae are similarly mobilized by also taking a wafer of bone with the oscillating saw and then bluntly dissecting the muscle to allow transfer.

Preparing transfer sites:

The spine of the scapula is then identified as laterally as possible and soft tissue removed with electrocautery including elevation of the supraspinatus and infraspinatus. A motorized burr is then used to abrade the bone on the top of the spine of the scapula and #2 high-tensile strength sutures are placed through the scapular spine starting as far laterally as possible and moving medially.

Transfer:

The transfers can be performed in order medial to lateral or lateral to medial; we prefer to start with the rhomboid major. Using the prepared sutures, the rhomboid major is taken to the medial most aspect of the prepared spine and the sutures clamped in place. This will recreate the vector of the ascending branch of the trapezius and is in a different location than a standard Eden-Lange transfer. A modified Mason-Allen suture is performed which also incorporates the bony fragment.

The rhomboid minor is placed slightly more lateral and just superior to the rhomboid major, also along the prepared spine and in a similar fashion with holding sutures that also secures the bony fragment. This effectively recreates the transverse portion of the trapezius.

The levator scapula is taken as far laterally and superiorly on the spine as possible and then also secured. This will recreate the descending portion of the trapezius. With all three muscles and corresponding tendon-bone units now transferred, the bony fragments are held in place so that they are contacting the abraded surface of the scapular spine and sutures are tied sequentially, moving from lateral to medial (Figure 4).

Figure 4.

Closure:

The wound is irrigated and the trapezius can be closed back to cover over the transfers. A drain is placed and the subcutaneous tissue and skin are closed in layers. The patient is then placed in a shoulder immobilizer with cryotherapy cuff.

Pearls and Pitfalls of Technique

Pearls

• This technique allows a much more anatomic reconstruction of the pull of the trapezius, but differs somewhat from original descriptions of the Eden-Lange. There must be a working knowledge of the anatomy to create this reconstruction.

• The trapezius is often scarred down onto the rhomboids and can be very vascular, especially if the dissection is not done in plane. Careful use of electrocautery is beneficial during this step as opposed to sharp dissection.

• A pneumatic arm holder facilitates the dissection by allowing different motion based on the muscles that are wanted to put on stretch and allows your assistants to retract and not just position the arm. Placement of an arm holder is critical and should be evaluated and confirmed prior to prepping and draping.

Pitfalls

• If the subcutaneous dissection is not done with care, the atrophic trapezius may not be visualized which will lead to difficulty in identifying the rhomboids.

• If the dorsal scapular nerve has been injured as well, this transfer will not succeed as this nerve innervates the rhomboids and levator scapulae and thought should be toward a possible scapulothoracic fusion.

• The serratus anterior is in the field of the operation and as stated above, the insertion may be damaged during mobilization of the rhomboid major if the two muscles have adhesions between them. Failure to recognize this and repair the serratus anterior can lead to post-operative medial winging.

Potential Complications

Seroma, hematoma, deep or superficial infection can all occur. Unrecognized additional pathology can lead to continued winging if the winging was due to a multifactorial etiology.

Nonunion of the transfer can occur if the bone wafers are not positioned to be in contact with the prepared spine of the scapula or if the tendons are not secured prior to allowing motion, however this is rare. Neurovascular injury is not a commonly reported complication. Continued pain and incomplete correction of scapular motion can occur even when the surgery is performed technically correctly.

Post–operative Rehabilitation

Postoperative care consists of sling immobilization for 6 weeks to allow for healing. During this time, the arm is positioned in elevation to support the scapula and decrease tension on the transferred tendons. The immobilizer is only allowed off for showering after the patient can demonstrate being able to support their operative arm with their contralateral arm.

The immobilizer is removed after 6 weeks and active and passive motion allowed to begin with physical therapy. Strengthening against resistance should not begin until after 12 weeks which can then progress to resumption of normal activities (Figure 5).

Figure 5.

Outcomes/Evidence in the Literature

Langenskiöld, A, Ryöppy, S. “Treatment of paralysis of the trapezius muscle by the Eden-Lange operation”. Acta Orthop Scand. vol. 44. 1973. pp. 383-8. (This early report describes use of the Eden technique with Lange’s modifications on three patients. The patients were aged from 38 – 44 years and all their injuries were due to blunt trauma. A curvilinear incision was used from just medial to the acromioclavicular (AC) joint to the medial border of the scapula. The levator was transferred with a small piece of bone to the lateral scapula close to the AC joint. The rhomboids also were detached with a small piece of bone and taken laterally to the infraspinatus fossa, secured with sutures through bone tunnels. Patients were casted for 4 weeks and then allowed to begin therapy. Subjective results were good in all patients. They noted that the rotatory component was not fully corrected which caused slight difficulty and residual pain.)

Bigliani, LU, Compito, CA, Duralde, XA, Wolfe, IN. “Transfer of the levator scapulae, rhomboid major, and rhomboid minor for paralysis of the trapezius”. J Bone Joint Surg Am. vol. 78. 1996. pp. 1534-40. (Twenty-two patients with trapezius palsy had a modified Eden-Lange performed. More than half of the patients’ etiologies were due to a previous surgery. All had failed conservative treatment for an average of 22 months. The levator was transferred to the lateral spine, the rhomboid minor to the midportion of the supraspinatus fossa and the rhomboid major to the midportion of the infraspinatus fossa with a thin piece of bone secured through drill tunnels. Average follow up with 7.5 years (range, 2 – 14 years). Pain improved from 4.3 to 0.9 on the visual analog scale (VAS) score. Thirteen patients had normal function on the American Shoulder Elbow Surgeons (ASES) score, six had satisfactory and three had difficulties with several activities. 19 patients regained overhead use of their arm. Although three patients had an unsatisfactory result, no complications were reported.)

Nakamichi, K, Tachibana, S. “Iatrogenic injury of the spinal accessory nerve. Results of repair”. J Bone Joint Surg Am. vol. 80. 1998. pp. 1616-21. (Seven patients were reported on who all had iatrogenic injury of the SAN during neck surgery. The average age of the patients was 29 (range, 24 to 44 years). The average time to surgical repair from the original surgery was 8 months (range 3 – 14 months). All patients were experiencing pain, weakness and drooping of the shoulder. At the time of revision surgery, one nerve was found to be in continuity and a neurolysis was performed, the remaining nerves had resection of interposed scar tissue and a direct end-to-end repair performed under microscopy. After an average follow-up of 32 months (range 24 – 39 months), four patients had regained normal function and three patients reported no pain or fatigue with ADLs but stated they had fatigue with heavy lifting or repetitive overhead activities. These authors recommend early nerve exploration in the case of an iatrogenic injury when spontaneous recovery does not occur.)

Wiater, JM, Bigliani, LU. “Spinal accessory nerve injury”. Clin Orthop Relat Res. 1999. pp. 5-16. (This is a review article and although it doesn’t contain independent study outcomes of surgical procedures, it is a valuable resource for the treating orthopaedic surgeon to have in reference to SAN injury. The article discusses anatomy and biomechanics, etiology of SAN injuries, patient evaluation including history and physical examination, diagnostic studies and treatment options and outcomes of both operative and non-operative treatment. The authors discuss the different surgical treatments available and also describe their rationale for how they perform the Eden-Lange procedure.)

Romero, J, Gerber, C. “Levator scapulae and rhomboid transfer for paralysis of trapezius. The Eden-Lange procedure”. J Bone Joint Surg Br. vol. 85. 2003. pp. 1141-5. (Twelve patients with trapezius palsy causing scapular winging underwent an Eden-Lange procedure and were followed for a mean of 34 years. The traditional medialization of the tendons of the levator and rhomboids were performed with a bone chip, the levator was placed on the lateral spine and the rhomboids to the area of the infraspinatus. Constant score revealed excellent outcomes in nine, fair in two and poor in one patient who was also found to have a dorsal scapular nerve palsy. Pain was relieved in eleven patients and nine were able to have overhead function. Pain-free, functional long-lasting results were evident in almost all patients.)

Kim, DH, Cho, YJ, Tiel, RL, Kline, DG. “Surgical outcomes of 111 spinal accessory nerve injuries”. Neurosurgery. vol. 53. 2003. pp. 1106-12. (This article reviews over 100 iatrogenic injuries to the SAN during a 23 year period, there were also eight stretch injuries and three patients with traumatic lacerations. The mean patient age was 36 years (range, 6 to 74). There were 87 patients during this time course that also had a SAN injury and were treated non-operatively due to improving clinical course. The most common cause of injury was benign lymph node biopsy. The average time to surgery was 27 months (range 12 – 44 months). Surgery involved extending the initial surgical incision to permit exposure of the SAN and the distal exposure of its branches as it entered the trapezius muscle. After resection of interposed scar tissue, a nerve graft was performed or an end-to-end repair based on the mobility; if the nerve was still in continuity then a neurolysis was performed. Based on this criteria, 58 patients had a graft placed, 26 underwent an end-to-end repair. Of those patients, 77% achieved a Grade 3 or better which is considered a favorable functional recovery and 60% reached Grade 4 or better.)

Teboul, F, Bizot, P, Kakkar, R, Sedel, L. “Surgical management of trapezius palsy”. J Bone Joint Surg Am. vol. 86-A. 2004. pp. 1884-90. (Twenty-seven patients with a trapezius palsy underwent surgical intervention with ten patients treated with neurolysis, nerve grafting in eight and direct surgical repair of the SAN in two patients. Seven patients were treated with the Eden-Lange transfer procedure, three of which had already failed a nerve repair. The average age of the patient was 38 (range, 15 – 75). Twenty-one of the patients had a neck previous surgery as their etiology of injury. The Eden-Lange procedure was performed with both rhomboids transferred below the scapular spine. Patients were followed for a mean of 35 months (range 12 – 140 months). Sixteen of the twenty patients treated with nerve surgery had a good or excellent result compared to four out of seven patients who had the Eden-Lange performed. Patient age over 50 and nerve lesion caused by radical neck dissection, penetrating trauma or spontaneous palsy were found to be predictive of poor results. The authors recommend an attempt of nerve repair if the injury is less than 20 months old.)

Galano, GJ, Bigliani, LU, Ahmad, CS, Levine, WN. “Surgical treatment of winged scapula”. Clin Orthop Relat Res. vol. 466. 2008. pp. 652-60. (Six patients with trapezius palsy causing scapular winging underwent a modified Eden-Lange procedure and ten patients with LTN palsy resulting in scapular winging underwent a direct transfer of the sternal head of the pectoralis major tendon without graft. Symptoms had been present for an average of 5 years in the trapezius palsy patients. The modified Eden-Lange procedure was also performed in the lateral decubitus position with the head of the bed elevated 15 degrees. A 10 cm incision is made medial to the medial border of the scapula and used to detach the levator scapulae and the rhomboids and transferred laterally with the rhomboid minor attaching to the supraspinatus fossa and the rhomboid major attaching to the infraspinatus fossa. The levator scapulae is transferred to the posterior edge of the acromion through a separate incision. Patients were followed for an average of 44 months post-operatively. The patients undergoing the modified Eden-Lange procedure had improved ASES score, mean flexion and VAS pain scores, they were also all satisfied with the procedure. Two patients had superficial infections treated with subsequent surgery.

Summary

Scapular winging due to trapezius palsy is often a misdiagnosed condition that is the cause of shoulder dysfunction. The etiology of injury is usually due to a nerve injury from a previous surgery involving the posterior cervical triangle. Non-operative management is not successful in the majority of cases. There should be consideration of early nerve repair and consultation with an appropriate specialist before the decision is made to perform a tendon transfer. Traditionally, the transfer developed by Eden and later modified by Lange involves a lateral transfer of the levator scapulae as well as the rhomboid major and minor. There are variations that exist that attempt to recreate the three distinct portions of the trapezius by altering the placement of the tendons. Regardless of the exact location of the tendons, this transfer appears to be a stable, reproducible procedure to decrease pain and improve function that does not have a high complication rate.

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