538 - A Case of Lateral Cord Plexopathy Following Shoulder Arthroscopy

Case Diagnosis: Lateral Cord Plexopathy

Case Description: Patient with previous right shoulder arthroscopy for labral tear and posterior shoulder instability presented for electrodiagnostic studies. Reported right second and third digit numbness, with weakness in flexion of right first to third digits and inability to flex the first and second fingers since arthroscopy. Physical exam revealed profound loss of strength in the flexor digitorum superficialis and profundus, flexor pollicis longus (FPL), and abductor pollicis brevis (APB). Sensation to light touch is severely diminished on the ventral right second and third fingers, and dorsal second finger. Tingling with light tough on the right distal lateral palm and hand.



Electrodiagnostic studies were performed of the right upper extremity. Normal median and ulnar sensory responses. Needle EMG of right pronator teres, FPL, and APB showed fibrillations and positive sharp waves.

Discussions: Diagnostic testing is consistent with a right brachial plexopathy, affecting the lateral cord and median nerve. Potential complications from shoulder arthroscopies include upper brachial plexus and peripheral nerve injuries. There are two positions for a shoulder arthroscopy: beach chair (BC) or lateral decubitus (DC). The lateral decubitus positions the arm parallel to its long axis using a holding device. The upright seated BC position allows the arm to be manipulated into different positions. Individual surgical positions depend on surgeon experience and planning for individual patients. The most common complication in the LD position is a brachial plexus injury due to intraoperative traction. The BC position aims to address the risk of brachial plexus injuries, however, it has an increased risk of hypotension and bradycardia.

Conclusions: Brachial plexus injury following shoulder arthroscopy is an infrequent but notable complication. Proper patient positioning, focused on reducing strain on the brachial plexus, must be a preoperative consideration. Appropriate follow up must be done to ensure that neurological complications are diagnosed quickly.