Exposure of the Acetabulum. Anatomical and surgical considerations

This text is a general description of a curettage of an aneurysmal bone cyst (ABC) in the acetabular-roof. Focus is on anatomic structures and muscle resection. Good pre‐operative imaging is needed which allows adequate pre‐operative planning. To expose the anterior and posterior columns both from both extra- as well as intrapelvically, many anatomic structures have to be identified. Normal structures and its localizations should be known to avoid nerve or vessels damage. Approaches to the acetabulum are very complex and demanding. Because each approach only gives access to a limited part of the acetabulum, preoperative planning and understanding of the anatomy is crucial for the success of the surgery. Therefore, preoperative radiological imaging including computerized tomography and MRI are instrumental. The anterior approach allows access to the anterior column and anterior lip of the acetabulum. The posterior approach allows access to the posterior column and posterior wall of the acetabulum. The ilioinguinal approach allows access to the medial part of the acetabulum and the anterior column. Because of the wide expansion of the ABC into the roof and posterior wall of the acetabulum with involvement of the anterior and posterior columns, we decide to use a iliofemoral approach with the option to extend it into a modified triradial approach. In addition, this approach allows us to control the ABC from the inside of the pelvis and offers the expansion to the quadrilateral wall in case of brake-through during surgery.