Pelvic osteotomies: anatomic pitfalls at the ischium. A cadaver study.

Pelvic osteotomies for acetabular dysplasia include an osteotomy of the ischium. The potential anatomical hazards of three different osteotomies of the ischium were assessed by performing a triple osteotomy in a series of 8 fresh cadaver pelvises. An oblique osteotomy above the sacrospinous ligament using a posterior approach requires that the inferior gluteal and pudendal neurovascular bundles be mobilised and retracted. A transverse osteotomy below the sacrospinous ligament using a posterior approach can be performed in a relatively safe area between the pudendal and sciatic nerves. A transverse osteotomy from anterior can be performed through a modified Smith Peterson approach. The pudendal nerve medially, the sciatic nerve laterally and the medial circumflex artery distally are not visualised and are prone to damage.