EVOLUTION OF THE TECHNIQUE
The classic ilioinguinal approach was described by Letournel in 1960 as a means of addressing acetabular fractures with the patient in the supine position.1 The original description involves the utilization of 3 windows: lateral, middle, and medial (Fig. 1). As described, the ilioinguinal approach gives near full access to the intrapelvic surface of the acetabulum and pelvic brim. The middle window allows the surgeon to access the rami and facilitates screw insertion in this region. The main working windows are the lateral and middle windows. Each of the 3 windows provides a portion of the exposure, but the pelvic brim cannot be viewed in its entirety through any 1 of them.
The modified Stoppa exposure or anterior intrapelvic approach (AIP) was adopted from general surgery in 1994 for use with acetabular fracture reduction and fixation.2 It provides direct access to the true and false pelvis, permits direct visualization of the quadrilateral surface, and it facilitates placement of instrumentation from medial to lateral, which can be mechanically advantageous in certain fracture patterns. The operating surgeon works from the side of the table opposite the fracture and with careful dissection, full visualization of the pelvic brim, sciatic notch, and 80% of the quadrilateral plate can be obtained.3
The AIP modification of the ilioinguinal exposure is a hybrid of these 2 techniques that incorporates the benefits of both. In the following paragraphs, we will describe the technique and benefits obtained through the addition of the AIP approach to each of the 3 windows of the ilioinguinal approach.
The Medial/AIP Window
The medial window (window 3) is defined by the medial border of the femoral vessels and the lateral edge of the rectus abdominus and spermatic cord. Division of the rectus tendon has been described to provide access to the pubic rami.1 The AIP modification allows for a retro-ramus exposure of the pubic ramus, instead of division of the insertion of the rectus tendon. A Pfannenstiel skin incision is used, and the rectus fascia is split vertically in the midline between the left and right rectus muscle bellies. (see Figure, Supplemental Digital Content 1, http://links.lww.com/BOT/A249) The posterior edge of the rectus insertion is elevated off the pubic body, and this retro-ramus dissection is continued proximally around the pelvic brim (Fig. 2). This allows for near full exposure of the pelvic brim within 1 “window” and facilitates the placement and fixation of plates in an infrapectineal position. This direct access to the infrapectineal region also allows implants to be placed in a position and orientation that directly counters medial displacement forces. In addition to plating along the infrapelvic brim, instrumentation of the internal aspect of the posterior column may also be achieved. Exposure of the pubic symphysis and contralateral pubic body is possible, as the rectus insertion can be elevated from the anterior aspect of the rami without complete detachment. This is useful in cases of combined pelvic ring and acetabular pathology, which is more common than previously believed.4 The ability to adequately visualize and apply fixation across the pubic symphysis to the contralateral pubic body is also useful in cases where distal anterior column fracture lines and comminution involving the superior ramus require extension of the fixation construct to the contralateral hemipelvis.
The Middle Window
The middle window (window 2) is developed between the lacuna vasorum (femoral vessels) and lacuna musculorum (psoas tendon, femoral nerve, and lateral femoral cutaneous nerve). This window allows visualization of the pelvic brim as far anterior as the pubic root and the quadrilateral surface in profile. The purported benefit of the AIP approach is that it does not require opening the inguinal canal or directly handling the contents of the femoral triangle. By combining the 2 exposures, however, the pectineal fascia can be taken down in its entirety. This exposure allows for improved visualization of the obturator neurovascular bundle, the anastomosis of vessels between the external iliac system and the obturator system (corona mortis), and the quadrilateral plate both en face and in profile (Fig. 3). Reduction of the posterior column can be obtained through either the AIP or middle windows, depending on fracture orientation and surgeon comfort. The AIP alone does not afford as broad visualization anteriorly at the level of the anterior acetabular rim, and the middle window can prove useful for fractures that exit the acetabular roof and have comminution at the pectineal eminence. Fixation that parallels the quadrilateral surface may be accomplished through the middle window but can also be achieved with the AIP approach by incremental release of the rectus insertion. Having access to the middle window through the formal ilioinguinal approach combined with the infrapectineal visualization obtained through the AIP window simultaneously provides enhanced ability to reduce and instrument these complex fracture patterns.
The Lateral Window
The lateral window (window 1) is developed by releasing the external oblique from the iliac crest and elevation of the iliacus from the internal iliac fossa, thus providing access to the inner surface of the iliac wing from the sacroiliac joint to the anterior superior iliac spine and pelvic brim. The lateral window allows direct access to the proximal half of the pelvic brim and the cranial portion of the anterior column and permits the placement of posterior column lag screws. The visualization for the AIP window and the lateral window overlap in the region of the iliac fossa adjacent to the pelvic brim. The addition of the AIP window to the lateral window allows alternative placement of infrapectineal and suprapectineal plates. Suprapectineal plates can be instrumented through the AIP and lateral window, with screws oriented from the pelvic brim into the posterior column through the lateral window.
A modification of this approach may involve an osteotomy of the anterior superior iliac spine (ASIS) (Fig. 4). The inguinal ligament is left attached to the ASIS and the contents of the canal are brought medially, providing exposure to the interspinous region, anterior rim of acetabulum, and superior pubic ramus medial to the pectineal eminence. This modification facilitates the passage of clamps from the inner and outer table and direct access to the low anterior column and wall (Fig. 5). A similar technique of splitting the origin of the inguinal ligament can provide comparable visualization.
Surgeons well versed in either the ilioinguinal or AIP approaches often advocate that they can address the majority of fractures with their approach of choice. We believe that these approaches should not be considered in isolation; rather, they are logical extensions of each other. There exist complex fracture patterns, the treatment of which may benefit by the enhanced exposure afforded by the combination of these 2 approaches, and it would be advantageous for pelvic and acetabular surgeons to have this in their armamentarium.
This case demonstrates the addition of the middle window to the AIP. The AIP has largely replaced the ilioinguinal approach at our institution, but the middle window was incorporated in this case because of the comminution at the pectineal eminence. The patient presented with an associated both columns fracture with displacement through the acetabular roof exiting anteriorly at the level of the pectineal eminence (Figs. 6A–C). Access through the middle window aided reduction of the anterior acetabular rim and allowed easier trajectory for screw placement from anterior to posterior tangential to the quadrilateral surface (Fig. 7; image from another patient, similar exposure). Reduction of the columns was possible through a clamp passed through AIP window, with simultaneous fixation through lateral window (Figs. 8A, B). Final radiographs demonstrate good reduction through a single exposure (Fig. 9).
The authors thank Drs. Theodore Manson and Jason Nascone for their clinical pictures and radiographs and Lindsey Behrend for the illustration of Figure 2.
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