Ultrasound-Guided Approach to the Superior Gluteal Nerve: An Anatomical Study

Ultrasound-guided block of the superior gluteal nerve (SGNB) for pelvic girdle analgesia is sparsely documented in medical literature, motivating us to conduct an anatomical study aiming to describe a straightforward approach to this nerve, guided by clear anatomical references.

An anatomical study was conducted on fifteen cadaveric models (thirty pelvic girdles), utilizing ultrasound-guided SGNB with a low-frequency convex ultrasound probe. The probe was positioned over the iliac bone in a superolateral oblique plane, scanning from superolateral to inferomedial. Structures identified included: continuous iliac bone (Figure 1-A), beginning of the greater sciatic foramen (Figure 1-B), and piriformis muscle (Figure 1-C). Subsequently, the probe was retracted towards the continuous iliac bone (Figure 1-A) in the fascial plane between the gluteus medius and minimus muscles, identifying the superior gluteal artery, and injecting 5 ml of a solution mixture (methylene blue + iodine). Three-dimensional reconstruction (3D) using computed tomography (CT) and subsequent sectional anatomy were performed on five cadaveric models. Anatomical dissection by planes of each hemipelvis was carried out on ten cadaveric models.

In the 3D reconstruction via CT, contrast dispersion over the supero-lateral gluteal region was visualized (Figure 2). In anatomical dissection and sectional anatomy, methylene blue distribution was observed in the muscular fascial plane between the gluteus medius and minimus, affecting the superior gluteal vasculonervous bundle (Figure 3).

Intergluteal SGNB consistently affects the superior gluteal vasculonervous bundle, proving to be a straightforward technique guided by clear anatomical references.