Introduction Compression injury of the suprascapular nerve is an uncommon injury that sometimes remains undiagnosed. However, this neuropathy has a florid clinical course and correct examination will reveal muscular hypotrophy with the accompanying pathological manifestations. The suprascapular nerve (C5-C6) stems from the superior primary trunk of the brachial plexus. After crossing the cervical muscle, it enters the supraspinatus fossa and passes through the coracoid notch (also known as the suprascapular notch) below the transverse scapular ligament (Figure 1). The suprascapular artery and vein pass above the transverse scapular ligament, lateral to the nerve. Where the two branches (C5 and C6) join, a motor branch to the supraspinatus muscle and sensory nerves for the acromio-clavicular and gleno-humeral joints split off. Further, distally in the course of the nerve, there is a motor branch to the infraspinatus muscle (Figure 2). Material and method Between 1989 and 2000, we treated 86 cases of this injury. All patients were active tennis players presenting with pain at the back of the shoulder. Diagnosis Examination revealed hypotrophy of the infraspinatus muscle, but not of the supraspinatus muscle. Kopell and Thompson`s maneuver (crossing the arm in front of the body) was positive in almost all cases. Evaluation with EMG sometimes showed no activity at rest, and usually more activity during rotation exercises. Injection of an anaesthetic eliminated or lessened the pain in all cases. Radiographic studies showed that most of the notches were Rengachary Type IV. No synovial cysts or ganglions were identified by MRI or during surgery. The authors believe that the neuropathy is not caused by entrapment, but is the result of repetitive chronic irritation during adduction and protraction (Rengachary Sling Effect), which is when compression is maximal (e.g. during the follow through of the serve). Treatment Of the 86 cases diagnosed, 23 underwent surgery, either because pain prevented training or because surgery was indicated to speed up the healing process. In the first 18 cases, open surgery was used, via the posterior Grinblat approach. This consisted of an incision on the spine of the scapula, detachment of the trapezius muscle and dissection in the plane between the trapezius and supraspinatus muscles. The notch and the superior transverse scapular ligament were then identified by palpation, followed by resection of the ligament. To reduce morbidity (there were 3 cases of intolerance to suture and very unsightly scars) and to avoid long periods of immobilization of the arm, we started using the percutaneous endoscopic route at the end of 2000, as advocated by Dr. Sampson of California. This technique allows us to identify and resect the ligament, using two 4-mm incisions and arthroscopy instruments. This permits mobilization 24 hours postoperatively and thus requires a much shorter recovery time (Figures 3 a and b). Results In all cases the patients recovered completely and were able to continue playing tennis at their previous level. Recovery periods were different for the open surgery and the endoscopic surgery groups, although the end results were the same. Pain and atrophy of the infraspinatus muscle disappeared in all those who underwent surgery. Players who received conservative treatment, since surgery was not indicated, also recovered, but in 80% of these cases the atrophy remained. There were no cases of trapezius muscle detachment in the open surgery group, or of deep infections or damage to the nerve, artery or vein. However, three cases presented with intolerance to the subcutaneous sutures and almost all scars were unsightly. Discussion The question of whether surgery is necessary to improve healing of neuropathy of the suprascapular nerve has been a subject of debate. Surgery may be indicated in top-level athletes, for whom pressure of time is always an issue. Surgery was used in 24% of all cases described above, after careful evaluation of the pros and cons.
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