Sciatic Neuropathy Induced by the Lithotomy Position

To the Editor. —A recent medicolegal situation brought to our attention an unexpected, unexplained, and rare sciatic nerve injury associated with general anesthesia with the patient in the lithotomy position. One study 1 indicated a 0.4% occurrence rate. Several possible contributing factors have been suggested, including stretching of the sciatic nerve, 2,3 (F. Batres, MD, and D. L. Barclay, MD, unpublished data, 1979) pressure, hyperflexion of the back, 1 contusion of the nerve, 4 and passage of the fetus through the birth canal. 5 Another possibility is ischemia. In most persons there is a small branch of the inferior gluteal artery, the artery comitans nervi ischiadici, which is an embryonic remnant of the axial artery of the limb bud. During normal embryonic development its function is largely replaced by the development of the femoral artery. However, this axial or sciatic artery occasionally persists and accompanies the sciatic nerve throughout life