Midcervical flexion myelopathy after posterior fossa surgery in the sitting position: case report.

Midcervical Quadriplegia is a well-known complication of posterior fossa surgery performed with the patient in the sitting position. The case of a 24-year-old man with a fourth ventricular choroid plexus papilloma is described. The patient developed reversible quadriparesis after surgery in the sitting position; postoperative magnetic resonance imaging demonstrated a hyperintense area within the cervical cord at C5-C6 on T2-weighted images, which was considered to represent "midcervical flexion myelopathy." It is suggested that the prolonged stretch and compression of the cervical cord is the pathogenesis of this serious complication.