Anatomical and CT angiographic study of superior gluteal neurovascular pedicle: implications for hip surgery.

PURPOSE: To identify the site of incision with the lowest risk of injury of the superior gluteal neurovascular pedicle in the total hip arthroplasty with Hardinge's direct lateral approach. METHODS: Eight fresh donated bodies were dissected and the branches of the superior gluteal nerve (SGN) and superior gluteal artery (SGA) were dissected. The distance between the SGA and the apex of greater trochanter (GT) was also evaluated in vivo in 29 patients by CT angiography. RESULTS: We observed 12 spray pattern and 4 transverse neural trunk pattern of the SGN. In all cases the nerve runs inferiorly to the artery, with a mean distance of 0.5 cm. At the CT angiography the average distance between the main branch of SGA and the GT was 5.2 cm, indicating a mean distance of 4.7 cm from the SGN to the GT. Terminal branches of SGA are found until 2.7 cm from GT. CONCLUSIONS: This study analyzed the relationships between superior gluteal neurovascular pedicle and the GT in vivo (considering also the muscular tone), showing that during direct lateral access a safe area of 4.7 cm exists from the GT to the SGN and of 3.5 cm to its lower rami.