Neurosurgery of the peripheral nervous system: entrapment syndromes of the brachial plexus

Upper plexus thoracic outlet syndrome--case report

A 47-year-old right-handed female became aware of proximal ache and muscle weakness in the right shoulder and elbow in 1997. Atrophy of the right biceps muscle was recognized and the right deltoid, triceps, supraspinatus, and infraspinatus muscles were weak. The Morley test and elevated arm stress test were positive. Neurolysis of the brachial plexus and anterior scalenectomy were performed via a right supraclavicular approach. An abnormal fibromuscular band was identified passing between the upper and middle trunks and constricting the middle trunk. Another scalene muscle anomaly was found passing between the C-5 and C-6 nerve roots and connecting the anterior and middle scalene muscles. These muscles were resected, and thorough neurolysis was performed around all nerves and the trunks. Postoperatively, all symptoms completely resolved and the patient was discharged 5 days after surgery. Thoracic outlet syndrome (TOS) manifests as symptoms of lower cervical nerve involvements with hypesthesia and paresthesia. However, upper plexus TOS manifests as symptoms due to the involvement of the C-5 to C-7 nerve roots, and is relatively rare. Transaxillary first rib resection is performed as the primary operation for TOS, but supraclavicular scalenectomy is effective for upper plexus TOS.