Damage of the superior gluteal nerve after the lateral transgluteal approach of the hip. anatomical, clinical and electrophysiological study

ABSTRACT

Twenty-two patients who had undergone unilateral hip athroplasty using the transgluteal approach of Hardinge were studied. The abductor muscles of the hip joint were assessed electrophysiologically and clinically by Trendelenberg test six months after the operation. Electrophysiological evidence of damage of the superior gluteal nerve was found in two patients, while positive Trendelenberg was present in seven cases. In an effort to understand the mechanism of injury of the nerve, ten Egyptian cadavers were bilaterally dissected to expose the superior gluteal nerve. The course, pattern of branching and distribution of the nerve were evaluated. Two patterns of nerve distribution were recorded. The spray pattern in 90% of cadavers and the transverse neural trunk pattern in the remaining 10%. In both patterns all branches lied deep to the middle third of the undersurface of the gluteus medius muscle. A safe area devoid of any neural branches was detected in all cadavers. It is safe to extend the incision up to 4.8cm in a cephalic direction from the tip of the greater trochanter, before reaching the lower most branch of the superior gluteal nerve