Femoral neuropathy: a complication of lithotomy position under spinal anaesthesia. Report of three cases.

Three patients developed solitary unilateral peripheral femoral neuropathy after vaginal hysterectomy. All were operated under subarachnoid analgesia in the lithotomy position. Straight rod leg supports with swing stirrups were used and the procedures lasted for two and one-half hours. The complication is thought due to the extreme abduction of thighs with external rotation at the hip causing ischaemia of the femoral nerve as it is kinked beneath the tough inguinal ligament. The prognosis was found to be excellent with complete recovery within eight to ten weeks. The complication is preventable by using lateral thigh supports limiting the degree of abduction.