An uncommon mechanism of brachial plexus injury. A case report

To report a case of brachial plexus injury occurring on the contralateral side in a patient undergoing surgery for acoustic neuroma through translabrynthine approach.

A 51-yr-old woman underwent surgery for acoustic neuroma through translabrynthine approach in the left retroauricular area. She had a short neck with a BMI of 32. Under anesthesia, she was placed in supine position with Sugita pins for head fixation. The head was turned 45 degrees to the right side and the neck was slightly flexed for access to the left retroauricular area, with both arms tucked by the side of the body. Postoperatively, she developed weakness in the right upper extremity comparable with palsy of the upper trunk of the brachial plexus. Hematoma at the right internal jugular vein cannulation site was ruled out by CAT scan and MRI. The only remarkable finding was considerable swelling of the right sternocleidomastoid and scalene muscle group, with some retropharyngeal edema. An EMG confirmed neuropraxia of the upper trunk of brachial plexus. She made a complete recovery of sensory and motor power in the affected limb over the next three months with conservative treatment and physiotherapy.

Brachial plexus injury is still seen during anesthesia despite the awareness about its etiology. Malpositioning of the neck during prolonged surgery could lead to compression of scalene muscles and venous drainage impedance. The resultant swelling in the structures surrounding the brachial plexus may result in a severe compression.