Before Emile Letournel's1 cadaveric dissection-based development of the ilioinguinal surgical approach, surgical access to the anterior aspect of the acetabulum and innominate bone had been quite limited. Levine2 developed what has become known as the iliofemoral approach for fractures based on modification of the Smith–Peterson approach.3 This modification avoided dissection of the lateral aspect of the ilium in favor of exposure of the internal iliac fossa contiguous with the interval between the tensor fasciae latae and sartorius muscles distally. This approach was used early in the surgical experience of Professors Judet and Letournel4 in 15 cases, but then abandoned in favor of the ilioinguinal from the mid 1960s onward. Subsequent successful use of the ilioinguinal in the 2 largest single surgeon case series4,5 provided an important foundation for current treatment. Nonetheless, a number of concerns and limitations and also a desire to improve its utility prompted revision of the medial window of this approach.
ORIGIN OF THE MODIFIED MEDIAL WINDOW
Early experience by the senior author (K.M.) after returning from fellowship training with Emile Letournel defined a number of issues that provided the impetus for modification of the medial window.
The traditional approach requires circumferential mobilization of the external iliac vessels, which can be a daunting exercise for many orthopaedic surgeons. Moreover, dissection medial to the vessels can disrupt the adjacent areolar tissue containing the primary lymphatic channels from the lower extremity. This may result in lymphangitis and leg edema, which are typically transient but can be dramatic.4 In addition, identification of retropubic vascular communications between the obturator and external iliac systems can be challenging because of limited access. Cadaveric studies have shown that some type or vascular anastomosis is common, although aberrant takeoff of the obturator artery from the inferior epigastric (corona mortis) is much less frequent.6 Although bleeding complications related to these anastomoses are relatively rare, they can have substantial ramifications for both the patient and surgeon.
Previous Inguinal or Femoral Hernia Surgery
The original dissection required release of the conjoint tendon of the internal oblique and transversus abdominis muscles medial to the vascular lacuna, which can be difficult in the setting of previous hernia surgery. This is particularly the situation following a classic Cooper ligament repair or revision. The dissection is further complicated with mesh augmented repairs that are now common.
Access to the Symphysis and Contralateral Anterior Pelvic Ring
Surgical exposure of the pubic symphysis in the original ilioinguinal approach requires release of the ipsilateral rectus abdominis insertion and provides no access to the opposite anterior ring. Preservation of the rectus abdominis and concomitant pubic symphysis/contralateral pelvis access is desirable in more complicated, multifocal injury patterns.
The above issues led to cadaveric dissections in 1984 for evaluation of a revised medial window using a midline split between the rectus abdominis heads and avoiding dissection medial to the external iliac vessels. This change also required movement of the primary surgeon from the side of the acetabular fracture after completion of the lateral and middle windows to the opposite side of the operating table. This ilioinguinal approach with a modified medial window (Fig. 1) was taught to trauma fellows during its evolution in the mid 1980's and formally at acetabular and pelvic educational courses beginning in the early 1990. Cole and Bolhofner7 in 1994 reported the modified Stoppa approach that has many similarities with the modified medial window, with the important difference being that the middle window is omitted. Other reports have followed.8
The skin incision is biased distal to the iliac crest but follows its contour from just posterior to the gluteus medius pillar to a point just distal to the anterior superior iliac spine (ASIS). It then proceeds medially along the lower abdominal wall, extending well past the midline, 4–5 cm cranial to the pubic symphysis (Fig. 2). The lateral window is developed in the manner originally described.4 The external and adjacent internal oblique abdominal muscles are released from the iliac crest with a thick fascial/periosteal sleeve beginning posterior to the apex of the gluteus medius pillar and extending to the anterior superior iliac spine (Fig. 3). Contiguous with the abdominal oblique release, the iliacus origin is subperiosteally mobilized from the internal iliac fossa, and also along its distal extension over the anterior acetabular rim medial to the direct head of the rectus femoris. This dissection is facilitated by hip flexion of 50–60 degrees and is carried medially into the iliopsoas bursa. In injuries where an anterior column fracture is minimally displaced, the iliopectineal fascia can be safely released from the pelvic brim through this window to allow access to the true pelvis. When the anterior column is displaced anterosuperiorly, this release places the external iliac vein at risk. In these cases, the iliopectineal fascia release should be deferred until the middle window is developed unless preliminary reduction maneuvers and ligamentotaxis via distal/lateral traction are successful in reducing the deformity. The full exposure afforded by the lateral window can be expansive (Fig. 4).
Attention is then turned to the middle window, which is modified as follows. The release of the external oblique aponeurosis extends from the anterior superior iliac spine to the lateral border of rectus sheath. This release is cranial to the external inguinal ring and spermatic cord (or round ligament) (Figs. 5 and 6), which are typically palpated but not included in the primary surgical dissection field. Detachment of the lateral portion of the internal oblique/transversus abdominis conjoint tendon and transversalis fascia stops just medial to the palpable femoral artery (Fig. 7). This exposes the underlying iliopsoas muscle and femoral nerve (Fig. 8). The plane of the iliopectineal fascia is defined by blunt dissection to mobilize the external iliac vessels en bloc medially and the iliopsoas/femoral nerve laterally. No dissection is performed medial to the vessels. Once isolated by retractors medially for the vessels and laterally for the psoas/femoral nerve, the iliopectineal fascia can then be incised under direct visualization (Fig. 9) from the pubic root posteriorly to as far as the anterior aspect of the sacroiliac joint. The obturator neurovascular bundle is then identified and protected while the quadrilateral surface is exposed by elevating the obturator internus muscle (Fig. 10). Blunt retractors can be carefully placed in the lesser or greater sciatic notches. This window provides important access to the mid anterior column, anterior wall, and pelvic brim from the mid superior ramus posteriorly to the level of the sciatic buttress (Fig. 11).
The modified medial window starts in a manner similar to that required for a pubic symphyseal dislocation. The midline is identified by the linea alba and converging fibers of the rectus fascia. A split between the rectus muscle bellies is created from the symphysis proximally for about 10 cm (Figs. 12A and B). If the peritoneum is inadvertently entered in the cranial portion of the exposure, it should be repaired to make the subsequent steps easier. The operating surgeon then moves to the side of the table opposite the acetabular fracture to work from the midline laterally. Headlamp illumination is normally required despite long-standing efforts to develop suitable lighted retractors, which remain inadequate. The rectus muscle on the side of the injury is partially mobilized by sharp dissection, developing a distally based insertional flap that extends over the pubic body (Fig. 13). The rectus is retracted anteromedially by a Hohmann retractor placed anterior to the superior ramus and safely medial to the femoral vessels. The prevesicular space is packed with a laparotomy sponge posterior to a malleable retractor (Fig. 13). The iliopectineal fascia has been previously released from the pelvic brim through the lateral window and/or the middle window and long Langenbeck retractors can then be used to retract the rectus, iliopsoas/femoral nerve, and external iliac vessels anterolaterally to expose the pelvic brim and medial portion of the internal iliac fossa. Next, a search for vascular communications to/from the obturator vessels is completed. These are more often venous than arterial, and it is often unclear from this vantage point whether these anastomotic communications are with the external iliac or inferior epigastric systems (Fig. 14). Because of retraction required by the dissection, these communications are usually under some tension and therefore appear almost adherent to the base of pubis at the level of the obturator canal. Visualization of the obturator neurovascular structures can be enhanced by placement of a blunt Hohmann retractor in the lesser sciatic notch. These vascular communications can then be ligated or cauterized depending on their size and composition. Elevation of the pectineus muscle is performed as needed for full visualization of the superior ramus. This portion of the approach is typically conducted with hip flexed a minimum of 45 degrees.
Most fractures treated through this approach require extensile exposure of the quadrilateral surface. This entails subperiosteal elevation of the obturator internus that may have already been initiated through the middle window (Fig. 11). Retractors can be transiently placed lateral to the obturator system to facilitate this portion of the exposure. Blunt retractors can also be judiciously placed in the greater sciatic notch, generally avoiding the superior angle and the superior gluteal neurovascular bundle.
Full development of this medial window provides extensive access to the innominate bone from the midline to mid portion of the internal iliac fossa, and also to most of the medial surface of the posterior column (Fig. 15). It can also be easily extended to the contralateral hemipelvis.
Although the role of this modified medial window has expanded with time, Letournel's overarching principles of operating room logistics, reduction techniques, and sequence still form the basis for treatment. Fundamental within this framework is establishing stable (table-based) distal lateral traction through a Schanz screw in the proximal femur (see Figures, Supplemental Digital Content 1A–C, http://links.lww.com/JOT/A625, http://links.lww.com/JOT/A626, and http://links.lww.com/JOT/A627 showing use of the fracture table). In many cases, this will provide an important preliminary reduction via ligamentotaxis. The ability to place the femoral head in a progressively anatomic position can also facilitate subsequent reduction maneuvers with the head acting as a template. The choice of operating room tables can affect the relative utility of the different windows. This is particularly true for the lateral window in a large or muscular male operated on a fracture table where limited hip flexion (typically 25 degrees without improvisation) can limit access. In these cases, the middle and medial window take on added importance. Operating on a radiolucent flat top table with the leg prepped free allows much greater hip flexion at the cost of more complicated prep and draping.
Anterior column, associated both column and anterior column plus posterior hemitransverse fractures are the patterns most frequently operated on through this approach. As illustrated in an associated both column pattern (Fig. 16), the reduction strategy is clamp based and focused on anatomic extra-articular reduction of the anterior column to the intact remnant of the innominate bone. This fracture reduction is usually performed through the lateral window, although the middle and medial windows can be useful for fracture debridement, dealing with weight-bearing marginal impaction, articular debris, and reductions requiring an additional spatial perspective. After the anterior column has been reduced and stabilized, the goal becomes perfect articular reconstruction via reduction of the posterior column. Once again, this is typically a clamp technique that must take into consideration the rotational displacements and assumed gap on the retroacetabular surface. This reduction can be accomplished through any of the windows independently or in combination (Fig. 17; see Figure, Supplemental Digital Content 2, http://links.lww.com/JOT/A628 showing use of the Weber pointed reduction forceps). Although there has been increasing emphasis on quadrilateral surface fracture involvement, it is critical to remember that the importance of this anatomic area is primarily to aid in column reduction, as well as provide a point of force application for stable control of posterior column rotation.
The initial applications of the modified medial window were directed primarily at limiting dissection around the external iliac vessels, avoiding zones of previous inguinal hernia surgery and providing easier access to the pubic body and symphysis. However, by the late 1980s, the medial window was being used routinely for primary or complementary reduction maneuvers as noted above. Next, augmented fixation of the posterior column followed with sciatic buttress anchored plates on the quadrilateral surface where anterior to posterior lag or position screws were inadequate for rotational control (see Figures, Supplemental Digital Content 3, http://links.lww.com/JOT/A629, http://links.lww.com/JOT/A630, http://links.lww.com/JOT/A631, and http://links.lww.com/JOT/A632 and Supplemental Digital Content 4, http://links.lww.com/JOT/A633 and http://links.lww.com/JOT/A634 showing quadrilateral surface plating applications).
A 43-year-old man sustained a comminuted associated both column acetabular fracture with an atypical ipsilateral sacroiliac fracture subluxation in a motor vehicle accident (Figs. 18A–C). The sacroiliac joint and primary anterior column reduction were performed in the lateral window, whereas management of the pelvic brim comminution and posterior column required use of both the middle and modified medial windows (Fig. 18D; see Figures, Supplemental Digital Content 5, http://links.lww.com/JOT/A635 and http://links.lww.com/JOT/A636 showing the 5 years postoperative obturator oblique and iliac oblique radiographs).
This approach modification addresses many of the concerns regarding the original ilioinguinal approach while maintaining comprehensive surgical access. For orthopaedic surgeons unfamiliar with this regional anatomy, it has proven easier to both instruct and master. Mastery of 3 potential exposure corridors (Fig. 1) assures maximum flexibility when dealing with complex fracture patterns and should remain part of the core skill set of the pelvis and acetabular surgeon.
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acetabular fracture; ilioinguinal; surgical approach; obturator anastomoses; corona mortis; anterior intrapelvic; Stoppa; acetabulum; pelvis; reduction
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