Modified iliac spine wafer osteotomy for exposure during Bernese periacetabular osteotomy

The Bernese periacetabular osteotomy (PAO) is a well-established procedure for the management of symptomatic hip dysplasia. The associated Smith-Petersen exposure offers excellent visualization of the acetabulum and control of acetabular osteotomy and mobilization. The traditional exposure of the true pelvis involves osteotomy of the iliac wing in order to mobilize the sartorial and inguinal ligament insertion. However, full osteotomy of the iliac spine may necessitate screw fixation if a relatively large segment of bone is included. A known complication with screw fixation of the iliac wing osteotomy involves failure of fixation and screw back out. Moreover, the screw may irritate the patient even in the setting of adequate fixation. A larger osteotomy may also injure the lateral femoral cutaneous nerve (LFCN) as it travels near the anterior-superior spine. To minimize the risk of these potential complications, a wafer osteotomy may be used to develop a sleeve of tissue involving the sartorial insertion. This sleeve also mobilizes the entirety of the LFCN medially and affords protection throughout the procedure. Furthermore, the wafer osteotomy may be re-fixed to the stable pelvis during closure with simple heavy suture fixation alone, avoiding screw insertion or associated removal. Because only a wafer or bone is taken during the spine osteotomy, more bone is available at the anterior-superior iliac spine for fixation of the mobile fragment after repositioning. In this technical note, we describe the wafer osteotomy technique in further detail.