A twenty-seven-year-old man was injured in overseas combat by an improvised explosive device. He sustained ruptured tympanic membranes; a traumatic right knee disarticulation and left transfemoral amputation; an open zone I, APC-II pelvic fracture; an open coccygeal fracture; a complex gluteal/perineal wound; and scrotal injuries. Prior to arrival at our facility, he underwent debridement of the wounds with an exploratory laparotomy and rectosigmoid diversion.
The patient arrived at our institution five days after the initial injury with a Glasgow Coma Scale score of 10T. Radiographs demonstrated a 3.2-cm diastasis of the pubic symphysis with widening of the anterior aspect of the sacroiliac joint (Figs. 1-A through 1-C). He was taken urgently for debridement of all injuries, first in the supine position and then in the prone position. The gluteal/perineal wound had extensive tissue necrosis with exposed, desiccated, dysvascular bone. Because of the complexity of this wound (Fig. 2) and the need for frequent debridements in the prone position, he was not an ideal candidate for internal fixation or standard external fixation techniques.
On hospital day four, the patient underwent definitive management of the pelvic fracture. He was placed on a radiolucent table in the supine position. A minimally invasive spine instrumentation system was selected for fixation (DePuy, Warsaw, Indiana). Two 1-cm vertical incisions were made over the anterior inferior iliac spine (AIIS) on both sides. Blunt dissection was carried down to the AIIS, and a pilot hole was drilled in order to achieve accurate depth of insertion to a point above the greater sciatic notch. Orthogonal fluoroscopic views were obtained to ensure proper drill placement. Screw lengths were determined with use of direct and fluoroscopic measurements. Multiaxial 6.0-mm screws of appropriate lengths to a depth at the level of the greater sciatic notch were placed. Care was taken to avoid excessive screw length in order to prevent tenting of the skin with the hip in full extension. A 5.5-mm stainless steel rod was contoured to match the surface anatomy of the abdomen and the curve of the pubic symphysis on the inlet view to facilitate ease of insertion and prevent skin tenting. The rod was tunneled subcutaneously and placed into the heads of the screws. The lack of considerable force required to seat the rod was evidence that undue pressure was not placed on the underlying abdominal structures. The symphysis was manually reduced, and the rod was locked in place with set screws. At the conclusion of the procedure, there was no impingement or restriction of hip motion. Postoperative radiographs demonstrated reduction of the symphyseal diastasis to 1.2 cm, with reduction of the anterior aspect of the sacroiliac joint (Figs. 3-A and 3-B). The patient required twenty-two surgical procedures to achieve wound closure and soft-tissue coverage, a majority occurring in the prone position. He underwent standard rehabilitation with removal of the internal-external fixator at one year. There was no local infection, generalized sepsis, or loosening of the construct. Radiographs after removal of the fixator demonstrated maintenance of the reduction of the symphysis and the sacroiliac joint (Fig. 4).
Our patient sustained a blast injury that led to extensive, contaminated wounds and lower-extremity amputations. In patients returning from overseas combat, blasts account for 80.7% of musculoskeletal injuries that require medical attention7. Additionally, 82% of combat-related extremity fractures are open, reflecting the penetrating nature of these injuries. In the senior author’s (R.C.A.) experience, there is a higher incidence of open pelvic fractures seen at our institution compared with the relatively low frequency (0.1% to 4%) seen in the civilian setting1-4. These devastating injuries carry a high mortality rate, historically as high as 75%; more recent series have reported a range from 5% to 58%2,4.
The management of pelvic fractures has traditionally been nonoperative for stable fractures, while internal or external fixation has been used for unstable injuries. Stability, as defined by the Young-Burgess classification, is based on the integrity of the sacrotuberous, sacrospinous, and sacroiliac ligaments1. An APC-II injury has widening of the anterior aspect of the sacroiliac joint with disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. However, the posterior sacroiliac ligaments are not disrupted, thereby providing posterior stability of the fracture. Our patient presented with a unique problem for fixation given the extent of the open wound involving the gluteal/perineal region.
All fixation types were considered with regard to the setting of the wounds, risk for infection, and the necessity for repeat debridements in the prone position. Although anterior soft tissues about the symphysis were intact, there was extensive tissue necrosis posteriorly with nonviable bone. Internal fixation of an APC-II pelvic fracture can be achieved with an anterior plate that reduces the symphysis and the anterior aspect of the sacroiliac joint, thereby providing rotational stability. With intact posterior sacroiliac ligaments, posterior fixation is generally not required. However, in the setting of an open fracture, internal fixation must be carefully considered given the concern for infection, sepsis, and issues related to soft-tissue coverage8-11. Leenen et al. reported a 50% local infection rate, with 28% of patients developing generalized sepsis in a series of open, unstable pelvic fractures treated with internal fixation12. In our patient, who had extensive, contaminated soft tissues and presumed bacterial colonization, the risk for infection and/or sepsis with standard plate osteosynthesis was considered great.
External fixation can also be utilized as definitive fixation in open pelvic fractures. One option is an anterosuperior construct in which half-pins are placed in each iliac wing. Another alternative, similar to the technique utilized in our patient, is an anteroinferior construct, with the placement of pins through each AIIS, aiming to a depth above the greater sciatic notch. This produces a biomechanically more stable construct because it takes advantage of the dense supra-acetabular bone, which provides superior purchase and fixation along with a high rate of intraosseous pin placement13. In our patient, traditional external fixation methods would have provided stability to the pelvic ring. However, these methods would have created difficulty with prone positioning for debridements and would also have been more cumbersome during the patient’s rehabilitation as a bilateral amputee.
To our knowledge, few reports of the use of anterior subcutaneous fixation exist in the literature. In a series of twenty-two patients, Kuttner et al. reported good results, with 84% of patients returning to work14. Thirty-two percent of patients sustained lateral femoral cutaneous nerve injuries, with 14% not resolving. Additionally, 14% of patients had loosening of the fixation, and one required revision14. The construct utilized in our patient is in contrast to this technique, which describes making an incision over the iliac crest and dissecting down the inner table of the ilium for the start point. The technique we used minimized surgical morbidity while taking advantage of a shorter working distance from the fixator to the patient’s bone, thus creating a more stable construct. Additionally, the technique is similar to that for pin placement in a supra-acetabular construct, making it technically easier. However, care must be taken to adequately contour the stainless steel rod and avoid excessive screw length to prevent skin tenting with the hip in full extension.
We believe the risk for infection and/or osteomyelitis is minimized with the technique presented here because of the lack of surgical morbidity associated with soft-tissue dissection as well as the surgical exposure required for plate osteosynthesis in a patient with extensive wound contamination and tissue necrosis. Furthermore, the decreased surgical time and blood loss associated with this procedure is of benefit in a critically injured and compromised patient. However, this procedure should be reserved for only the most critically ill patient with extensively contaminated open wounds who is not an ideal candidate for plate osteosynthesis or standard external fixation.
In conclusion, complex soft-tissue injuries associated with pelvic fractures secondary to blast mechanisms are more severe than those associated with non-blast mechanisms. The severity of these injuries in the setting of a multitrauma patient often prohibits standard internal fixation techniques. In rare instances, standard methods of external fixation may also be difficult because of the injury and nature of the soft-tissue wound. Our case challenged us to seek alternative methods to provide stable fixation with minimal soft-tissue disruption while facilitating the patient’s rehabilitation as an amputee.