Posterior Fossa Surgery

Case Synopsis

A 53-year-old woman undergoes posterior fossa craniotomy for removal of a right acoustic schwannoma. Preoperative symptoms included tinnitus, episodic vertigo, headache, facial asymmetry, and loss of coordination and balance. The surgeon will use a retrosigmoid approach and is planning for supine elevated right shoulder position and the intraoperative use of somatosensory evoked potentials (SSEPs); brainstem auditory evoked potentials (BAEPs); and facial, hypoglossal, accessory, and masseter electromyography (EMG). During the surgery, the neurophysiologist is unable to evoke EMG activity of the facial nerve. After extubation, the patient has a right-sided facial droop.