The course of the inferior gluteal nerve and surgical landmarks for its localization during posterior approaches to hip

Abstract

The position of the inferior gluteal nerve (IGN) makes it vulnerable to iatrogenic injury during posterior and posterolateral approaches to the hip. Although the posterior approach has been reported to be the most frequently used technique, it is most likely to be associated with damage to the IGN. As there is scant information in the literature regarding the course and the anatomic relationships of the IGN, we aimed to investigate the anatomic course of the IGN and define the anatomical landmarks that can be used by surgeons during posterior approaches to the hip. Thirty-six gluteal regions from adult fixed cadavers were used for this study. A triangular-shaped anatomic area that contains the IGN was defined. This geometric area was formed by connecting the following points: posterior inferior iliac spine (PIIS) (apex), ischial tuberosity (IT) and greater trochanter (GT). This triangle can further be divided into two, the upper triangle being the "danger zone" since it contains the IGN and its branches. The closest mean distance between the point of IGN origin and the PIIS, IT and the GT was 3.2, 4.8 and 5.4 cm, respectively. In all specimens, the nerve entered the deep surface of the gluteus maximus approximately 5.4 cm from the apex of the GT and approached the GT as close as 0.8 cm, on average. Based on our study, dividing the gluteus maximus with standard techniques may damage the IGN. Posterior minimally invasive approaches to the hip should take into account the point of entry of the IGN into the gluteus maximus. Localization of the IGN by using the anatomic triangle defined in this study may decrease surgical morbidity.