Indications
True scapular winging can cause significant shoulder pain and dysfunction. Winging occurs most commonly from an injury to the long thoracic nerve (LTN) resulting in dysfunction and serratus anterior paralysis. Without the stabilizing action of the serratus, the median border of the scapula translates medially and superiorly with attempted elevation of the arm. This produces a classic “angel wing” deformity that can be magnified by asking the patient to perform a push-up against the wall.
Winging due to serratus dysfunction should be distinguished from that of trapezius paralysis and from the generalized weakness of the periscapular musculature seen in fascioscapulohumeral dystrophy (FSH). Trapezius paralysis produces winging in which the scapula undergoes abnormal lateral and inferior translation during arm elevation. Shoulder ptosis is typically evident with the arm in the dependent position; the patient will demonstrate weakness with shoulder shrugging.
Although it is the third most common type of muscular dystrophy, FSH is uncommonly encountered in clinical practice. It is an autosomal dominant disorder associated with the subtelomeric region of chromosome 4q. Presentation of this disorder can be highly variably, but classically symptoms arise in the second or third decade and include fascial muscle weakness (inability to whistle or close eyes tightly), atrophy of the biceps and triceps, and winging of the scapula. Winging may have a mixed pattern and can range from mild to severe. In patients with suspected FSH, neurology consultation should be sought.
The long and superficial course of the LTN makes it vulnerable to injury. Long thoracic nerve palsy can result from acute or repetitive trauma, viral illness, Parsonage-Turner syndrome, or improper patient positioning during surgery or it may be idiopathic. Most LTN palsies are self-limited neuropraxias and patients presenting with serratus dysfunction should be initially managed nonoperatively. Serial electromyographic and nerve conduction tests are useful in evaluating recovery and should be done at 3-month intervals. Range of motion exercises help to prevent shoulder contractures, but their therapeutic benefit is difficult to separate from the general improvement in function that most patients experience. Bracing can effectively stabilize the scapula and improve motion but is often poorly tolerated.
Recovery may take as long as 2 years, particularly when the etiology is not traumatic. Patients who do not improve after this period are candidates for muscle transfer procedures. Transfer of the sternal head of the pectoralis major is the most popular because it has the desired excursion and orientation to substitute for the serratus. It also has similar power and electromyographic activity.
Preoperative Planning
Evaluation of the patient with a winging scapula should include a comprehensive physical exam and x-rays of the cervical spine, chest, and shoulder. Although these images are rarely diagnostic, they may identify contributing lesions such as cervical spondylosis or a scapular osteochondroma. Nerve testing, which includes evaluation of the spinal accessory nerve and the entire brachial plexus, should be routinely obtained. Neurologic involvement beyond the LTN can compromise the results of partial pectoralis transfer and is important to recognize preoperatively. The scapular stabilization test, done by manually stabilizing the scapula against the thorax and asking the patient to elevate the arm, can demonstrate improvement in active motion likely to be achieved following successful surgery.
Positioning
This procedure is typically done in a beach chair position modified so that the patient is slightly more upright, allowing access to the midline of both the anterior and posterior chest. The scapula should be draped free and easily manipulated. Use of an articulated arm holder allows for appropriate positioning of the arm and facilitates exposure both in front and in back.
If use of an autograft is planned, the ipsilateral leg is also prepped and draped.
Approach
A 10- to 15-cm incision is used and is placed in the axillary skin crease. Proximally, the deltopectoral interval is developed and the cephalic vein is retracted laterally. The entire pectoralis major tendon is exposed. The tendon of the sternal head lies deep to that of the clavicular head. The individual muscle bellies can be bluntly separated medial to their musculotendonous junctions. This is aided by abduction and external rotation of the arm.
Exposure of the inferior angle of the scapula is accomplished by blunt dissection along the chest wall. Care is taken to stay medially and avoid the lateral neurovascular structures. The latissimus dorsi and teres major muscles are retracted inferiorly. The inferior scapula can then be grasped with a towel clip and pulled anteriorly into the field. It is exposed through subperiosteal dissection of the attached musculature. It is helpful to have an assistant pull forward into the medial border of the scapula, which can be palpated through the skin and subcantaneous tissues.
An alternative, two-incision technique has also been described.1 The anterior incision is made just lateral and inferior to the coracoid process, extending 4 cm. The pectoralis tendon is exposed as described above. The arm is then placed in flexion and slight adduction using the articulated arm holder. A second incision is made over the inferior angle of the scapula in line with the skin creases. Dissection is carried down to the level of the latissimus dorsi muscle, which is split sharply exposing the teres major. The teres major is then elevated subperiostealy off the inferior scapula, exposing the deep and superficial sides of the inferior angle. Blunt dissection along the chest wall creates a tunnel between the posterior and anterior exposures through which the transferred tendon can be passed.
Techniques
After release of the sternal portion of the pectoralis major tendon, Krakow grasping stitches are placed along the tendon. It is then augmented with a strip of autograft fascia lata. The fascia lata can be harvested through two small incisions on the lateral thigh using a tendon stripper. It is folded over itself several times and reinforced with nonabsorbable sutures. The graft is then weaved through the pectoralis musculotendinous junction in a Pulvertaft fashion (Figure 3). Use of hamstring tendons or allograft Achilles tendon for this purpose has also been described.
A 6- to 8-mm hole is drilled in the inferior angle of the scapula. A 1-cm bone bridge should be left between the hole and the scapula border to prevent fracture. The scapula is then manually reduced by the assistant. The ends of the Krakow stitches and the graft-augment are passed through the scapula and pulled until there is direct contact between the native pectoralis tendon and the scapula. The graft augment is then sewn back upon itself and to the native tendon with heavy nonabsorbable sutures to improve fixation.
If using the two incision technique, a large clamp is passed through the soft tissue tunnel in a retrograde fashion to grasp the Krakow stitches and pull the tendon into the distal wound. It is then passed through the scapula and fixed as described above.
Wounds are closed in layers and suction drains are used routinely.
Pearls and Pitfalls
The role of graft augmentation is controversial. It should be emphasized that the graft is not needed and should not be used to increase the length of the transferred musculotendinous unit.2 If used as a bridge to attach the pectoralis tendon to the scapula, the graft will stretch out and winging will recur. Contact between the native tendon and the scapula is critical and the graft should function only as an augment to fixation.
Postoperative Care
Postoperatively, patients are placed in a custom scapulothoracic orthosis for 6 weeks. The brace functions to press the scapula against the chest wall and relieve tension on the transferred tendon. Gentle range of motion exercises are begun after this period of time. Delayed therapy has not resulted in shoulder stiffness in our experience. No heavy lifting or manual labor is allowed for 6 months.
Outcome
Several reports in the literature have illustrated the success of partial pectoralis major transfer.
- Post provided an early description of the use of fascia lata augmentation and transfer of the pec sternal head, reporting a return to full motion and no pain in seven of his eight patients.3
- Steinman at al reported good or excellent results in six of nine patients using the same technique.4
- Connor et al reported successful resolution of winging in 91% of patients treated with the specific technique described here.5
- Warner and Navarro achieved resolution of winging in seven of eight patients treated with a two-incision technique and autograft hamstring augmentation who were followed for more than 2 years.1
Warner and Navarro's report highlighted the frequent misdiagnosis and mistreatment of scapular winging. The eight patients in their series had received five misdiagnoses and undergone a total of 17 surgical procedures prior to presentation.1
Complications
Recurrence of winging is estimated in 9% of patients. Often, this is due to patient noncompliance with postoperative restrictions or a failure of operative technique, specifically not attaching the native pectoralis tendon directly to the scapula. Seroma at the site of fascia lata harvest has also been reported but can be minimized with the harvest technique described here. Rather than using a large single incision followed by wide graft harvest, use of two smaller incisions and harvest of a longer but thinner graft with a tendon stripper reduces soft tissue dissection and “dead space” formation.
References
- Warner JJ, Navarro RA: Serratus anterior dysfunction. recognition and treatment. Clin Orthop Relat Res 1998;(349):139-148.
- Povacz P, Resch H: Dynamic stabilization of winging scapula by direct split pectoralis major transfer: A technical note. J Shoulder Elbow Surg 2000;9:76-78.
- Post M: Pectoralis major transfer for winging of the scapula. J Shoulder Elbow Surg 1995;4:1-9.
- Steinmann SP, Wood MB: Pectoralis major transfer for serratus anterior paralysis. J Shoulder Elbow Surg 2003;12:555-560.
- Connor PM, Yamaguchi K, Manifold SG, Pollock RG, Flatow EL, Bigliani LU
