Nerve relationships to the sacrospinous ligament: application to suspension procedures and transgluteal approaches for nerve repair and tumor removal with three case illustrations

Background Transvaginal suspension procedures often use the sacrospinous ligament (SSL), which attaches onto the ischial spine (IS). However, nerve-related sequelae (e.g., sciatic nerve injury) following such procedures have been reported. Therefore, the current anatomical study was performed to better understand these relationships. Additionally, three case illustrations of patients with injury to the sciatic nerve following sacrospinous ligament suspension procedures are included to exemplify the significance of a thorough knowledge of this anatomy. Methods In 20 human adult cadavers (40 sides), a gluteal dissection was performed to expose the IS and SSL and regional nerves near the greater sciatic foramen. Measurements between the IS and SSL were made between these structures and surrounding nerves. Results The average distance between the IS and sciatic nerve was 1.4 cm. From this bony part, the average distance to the S1 and S2 ventral rami was 3.1 cm and 1.9 cm, respectively. From the IS to the lumbosacral trunk, pudendal nerve, nerve to obturator internus, and superior gluteal nerve, the mean distance was 4 cm, 0.5 cm, 0.7 cm, and 4.5 cm, respectively. From the SSL to the lumbosacral trunk, S1 ventral ramus, and S2 ventral ramus, there was an average distance of 4.2 cm, 1.6 cm, and 0.8 cm, respectively. Statistically, in females, the distances from the IS and SSL to the sciatic nerve, lumbosacral trunk, superior gluteal nerve, and S1 and S2 ventral rami were shorter when compared to males. Conclusion An improved understanding of the relationship between the SSL and IS and nerves near the greater sciatic foramen can lead to fewer intraoperative complications during approaches to various peripheral nerves in this region. Lastly, these relationships might help better understand the nerve injuries following pelvic suspension procedures that use the SSL.