442 - Medial and Lateral scapular winging following intramedullary brainstem tumor resection: A case report

A 52-year-old male presented to EMG Lab referred for right medial scapular winging, and concern for long thoracic nerve injury, after left lateral craniotomy resection of intramedullary brainstem tumor and left C1 hemilaminectomy. He was noted to have a limited range of the right shoulder with painful movement at end-range abduction. The motor NCS of the right accessory nerve and right long thoracic nerve demonstrated prolonged distal motor latencies and reduced CMAP amplitudes compared to the unaffected side. EMG was significant for active denervation and chronic reinnervation changes in the right trapezius with no active or chronic changes noted in the serratus anterior.

Discussions:

Medial scapular winging is seen in serratus anterior muscle weakness caused by long thoracic nerve dysfunction, with the serratus anterior keeping the scapula more lateral and protracted. Lateral scapular winging is seen in trapezius muscle weakness and spinal accessory nerve dysfunction (CN XI), with the trapezius keeping the scapula more medial and allowing for shoulder abduction from 90 degrees and up. The long thoracic nerve injury in this patient was likely due to positioning during surgery, as the patient had compression over the long thoracic nerve for an extended period. The spinal accessory nerve was likely injured during the mass resection as depending on the level of injury the nerve innervates the contralateral trapezius and ipsilateral sternocleidomastoid.

Conclusions:

Electrodiagnostics is an excellent tool for diagnosing and determining the degree of severity of nerve injury. Electrodiagnostics also aids the clinician as an extension of the physical exam. The patient discussed was referred for medial scapular winging and suspected long thoracic nerve injury, however, due to the electrodiagnostician noting subtle lateral winging the injury to the spinal accessory nerve was also discovered.