Minimally invasive anterolateral approach to the hip: risk to the superior gluteal nerve.

BACKGROUND

Minimally invasive approaches to the hip show promise of less muscle trauma compared to conventional approaches. What is the risk of damage to the superior gluteal nerve? We studied the course of the superior gluteal nerve.

METHOD

20 legs of 11 formalin-fixed Caucasian cadavers were dissected and the course and the distances of the superior gluteal nerve branches from the tip of the greater trochanter were documented.

RESULTS

The branch of the gluteal superior nerve leading to the gluteal minimus muscle was 33 (20-50) mm from the tip of the greater trochanter, within a deeper layer. The nearest point of the superior gluteal nerve branches from the tip of the greater trochanter in the posterior region was 19 (10-30) mm, in the middle region 20 (20-30) mm and in the anterior region 20 (10-35) mm. In half of the cases, a distal intermuscular branch between gluteal medius and tensor fasciae latae muscle could be found, mean 27 (10-40) mm caudal and 38 (25-60) mm ventral to the tip of the greater trochanter. This distal branch is considered to create a loop with upper branches of the superior gluteal nerve within the tensor fasciae muscle.

INTERPRETATION

The safe zone for the superior gluteal nerve was smaller than previously reported. Use of a minimal direct lateral approach puts the inferior branches within the gluteal medius at risk; however, a minimal anterolateral approach to the hip may compromise branches of the superior gluteal nerve to the tensor fasciae latae muscle.