Anatomical Proximity Between Sciatic Nerve and Ischial Spine and its Relationship to the Development of Deep Gluteal Pain Syndrome

Objective Deep gluteal syndrome (DGS) is a medical diagnosis in which the pathoanatomy of the subgluteal space contributes to pain. The growing recognition that gluteal neuropathies can be associated with the presence of a bone-neural conflict with irritation or compression may allow us to shed some light on this pathology. This study aims to determine whether the location of the sciatic nerve in relation to the ischial spine contributes to the development of DGS. Methods The sciatic nerve – ischial spine relationship was analyzed based on magnetic resonance imaging (MRI) in 15 surgical patients who underwent piriformis release, and in 30 control patients who underwent MRI of the pelvis for reasons unrelated to sciatica. The sciatic nerve exit from the greater sciatic foramen was classified as either zone A (medial to the ischial spine); zone B (on the ischial spine); or zone C (lateral to the ischial spine). Results The sciatic nerve was significantly closer to the ischial spine in surgical patients than in MRI controls (P=0.014). When analyzing patients of similar age, sciatic nerves in surgical patients were significantly closer (P=0.0061) to the ischial spine, and located in zone B significantly more (P=0.0216) as compared to MRI controls. Patients who underwent surgery for piriformis release showed a significant decrease in pain postoperatively (P<0.0001). Conclusions The results from this study suggest that the relationship between the ischial spine and sciatic nerve may play a role in the development of DGS. This may also help establish which patients would benefit more from surgical intervention.