Session I - Pelvic Trauma

Is the Posterior Approach to Pelvic Ring Injuries Associated with a High Rate of Soft Tissue Complications?

Michael D. Stover, MD, Loyola Medical Center, Maywood, IL; Stephen H. Sims, MD, Carolinas Medical Center, Charlotte, NC; David C. Templeman, MD, Hennepin County Medical Center, Minneapolis, MN; Paul Merkle, MD, LA County Medical Center, Los Angeles, CA; Joel M. Matta, MD, Good Samaritan Hospital, Los Angeles, CA

Purpose: To define the incidence of soft tissue complications following the posterior approach for patients who underwent open reduction and internal fixation of Type III unstable pelvic fractures treated less than three weeks following injury.

Introduction: The posterior approach to the pelvis has been avoided by some surgeons in recent years due to a perceived high incidence of post- operative soft tissue complications. Bucholz classified pelvic ring injuries according to degrees of instability. Type III injuries involve anterior and posterior injuries to the pelvic ring, with resultant instability in the sagittal plane. These represent high-energy fractures and are commonly associated with other injuries. Poor outcomes associated with nonoperative treatment of these unstable injuries prompted investigations into alternative methods of treatment. Open reduction and internal fixation of displaced pelvic fractures has since been shown to improve clinical results. Due to reports of high soft tissue morbidity associated with the posterior approach to the pelvic ring, an anterior approach and plate fixation has been advocated by some. More recently, closed reduction and percutaneous internal fixation of the sacrum or sacroiliac joint have been described with the patient in the supine position to avoid the possible morbidity of the extensive posterior dissection and the prone position necessary for the posterior approach. Other authors have not experienced the high complication rates associated with the posterior approach, but these series have been small due to the relative rarity of this injury. To better define the morbidity associated with this approach, a multicenter analysis of complication rates of surgeons who commonly utilize this approach was undertaken.

Materials and Methods: At four different centers, all patients with a posterior approach to their unstable posterior pelvic ring injuries were retrospectively reviewed. One hundred fifty-three patients were identified; the average age was 32 years (range 7-74). Of 131 patients with unilateral injuries, fracture patterns included 60 sacroiliac fracture-dislocations, 37 sacral fractures, 32 sacroiliac dislocations, and 2 iliac wing fractures. Bilateral injuries included 4 "H" type sacral fractures, 7 bilateral sacral fractures, 3 bilateral sacroiliac fracture-dislocations, 3 bilateral sacroiliac dislocations, and the remaining 5 involving differing posterior injuries to each side.

Twenty had simultaneous bilateral approaches, while two were staged. Two fractures were open injuries. The mechanism of injury for 85 patients was a motor vehicle accident, 10 a motorcycle accident, 18 were struck by a car, 22 resulted from a fall, and 18 secondary to a crushing mechanism. Most had associated injuries including 35% with extremity fractures, 23% with chest trauma, 17% closed head injury, 15% intra-abdominal injury, 15% genitourinary injuries, and fractures of the spine or acetabulum in 11% and 10% respectively. Forty-two (27%) patients had evidence of a neurologic injury preoperatively, manifesting as numbness or weakness in a nerve root distribution, bowel or bladder incontinence, or erectile dysfunction. Twenty-two (14%) patients had an associated closed degloving injury, nine of which were in the surgical field. Time to surgery averaged 10.1 days (range 0-21). Fixation varied depending on the injury pattern and included iliosacral screws (6.5 mm cancellous), lag screws and reconstruction plates. Forty patients also had plate and screw fixation of the anterior ring injury.

Results: Five patients were noted to have prolonged (greater than five days) wound drainage, one taken back to the operating room for a washout and repeated closure. All resolved without infection. Two (1.3%) iatrogenic nerve palsies were recorded, both involving the fifth lumbar root and transforaminal sacral fractures. Six wound infections occurred (3.9%), all responding to repeated debridements; two had revision of the fixation at the time of debridement. No patients currently have evidence of active infection. No wound or soft tissue necrosis occurred following a posterior approach, although one patient required a soft tissue flap for soft tissue loss following debridement of an open injury.

Discussion: Fractures of the posterior pelvic ring are commonly associated with injuries to other body systems as well as other fractures. These injuries may not allow for expedient stabilization of the pelvic ring. The ability to obtain a satisfactory reduction is made more difficult with time, and an adequate closed reduction is usually not possible. The posterior approach allows access to the sacrum, sacroiliac joint, and ilium for reduction and fixation of all injuries to the posterior pelvic ring. It allows access to the bone of the posterior pelvis to debride or decompress structures and place clamps directly to bone for reduction maneuvers. Our study represents a combined group of patients from surgeons of differing experience, at four separate institutions, who follow a similar protocol for the reduction and fixation of unstable posterior ring fractures. Previous studies have reported infection rates ranging from 0-27%. Of the six infections in our study (3.9%), two patients had chronic alcoholism and malnutrition, one had abrasions in the area of the incision, and one was operated through a closed degloving injury. The average time to fixation in the six fractures was 7.3 days (range 3-14). With careful evaluation of patients and their soft tissues, open reduction and internal fixation of the pelvis through a posterior approach has an acceptable rate of soft tissue infections with no incidence of massive skin or soft tissue necrosis.

Conclusion: Previous reports of high soft tissue morbidity associated with the posterior approach to the pelvis have appropriately directed the attention to the condition of the soft tissues following injury. A careful evaluation of the soft tissue will help in making appropriate choices regarding techniques for reduction and fixation. A posterior approach for open reduction and internal fixation has an acceptable rate of soft tissue complications.