Lethality of Necrotizing Soft Tissue Infections after Blunt Rectal Injury

Abstract

Abstract

Background:

Unlike penetrating rectal injury, the management of blunt rectal injury remains controversial. These injuries, often seen in association with complex urogenital injuries, severe pelvic fractures, and perineal de-gloving injuries, require multi-specialty, multi-modality therapy for management. Despite aggressive management, necrotizing soft tissue infections (NSTI) of the pelvis and perineum occur. As a result of the rarity of these injuries, consensus regarding optimal management strategies does not exist.

Case Report:

We report three cases of NSTI after blunt rectal injury in association with complex pelvic fractures, resulting in a 67% mortality rate and substantial morbidity. Pre-disposing factors and potential management strategies to minimize morbidity and optimize survival are presented.

Conclusions:

Necrotizing soft tissue infections after blunt rectal injury in association with severe pelvic fractures are uncommon and have a high mortality rate. Early aggressive identification and multi-modal therapy including extensive pelvic and perineal drainage are required to improve outcomes.

Unlike penetrating rectal injuries, the management of blunt rectal injuries remains controversial [1]. Blunt injuries, often observed in association with complex urogenital injuries, severe pelvic fractures, and perineal de-gloving injuries require multi-modality therapy for optimal management. Despite seemingly ideal management, necrotizing soft tissue infections (NSTI) of the pelvis and perineum occur and are likely exacerbated by tissue ischemia from shock, tissue edema, as well as ischemia after angioembolization for pelvic fracture arterial hemorrhage control. The combined effect is a tissue bed that supports bacterial proliferation derived from the rectal injury. Because of the rarity of the injury, consensus regarding optimal management strategies is absent. We report several cases of NSTI after blunt rectal injury in association with severe pelvic fractures.

Case 1

A 23-y-old motorcyclist struck a tree at high speed. He was hemodynamically unstable with blood per rectum and transferred for management of his open book pelvic fracture. With resuscitation, he underwent embolization of his left internal pudendal and superficial circumflex femoral arteries followed by radical debridement of his open pelvic fracture, percutaneous left sacroiliac joint pining, perineal debridement, and a Hartmann procedure to manage a blunt distal rectal injury. His resuscitation induced secondary abdominal compartment syndrome, necessitating a decompressive re-laparotomy 12 h later. Unlike the initial debridement with only stool and clot in the perirectal space, this exploration noted malodorous effluent, and necrotic tissues without any identifiable stool. Extensive full-thickness perineal debridement for ischemia was required, necessitating a temporary abdominal closure (TAC). Multi-system organ failure and death occurred within 36 h of injury. Operating room cultures were polymicrobial, devoid of multi-drug–resistant organisms (MDRO), and all were sensitive to the prescribed β-lactamase inhibitor combination agent.

Case 2

A 44-y-old motorcyclist struck a wall at high speed. Evaluation at an outside hospital demonstrated an open book pelvic fracture without contrast extravasation, but found subcutaneous air in the scrotum and true pelvis suspicious for rectosigmoid injury. On transfer, resuscitation was coupled with immediate operation for hypotension. Sigmoidoscopy confirmed a large tear in the anterior rectosigmoid that led to laparotomy with end colostomy and a Hartmann pouch. Because of hemodynamic lability, a TAC and an external fixator were placed. A secondary abdominal compartment syndrome was identified within eight hours necessitating TAC revision, and an NSTI of the lateral pelvic sidewalls extending to the rectus sheaths bilaterally was found. The pre-peritoneal space was opened with evacuation of an infected hematoma and identification of a 4-cm anterior rectal tear in direct communication with the left superior pubic ramus fracture. The preperitoneal space was packed and a TAC reapplied. His fulminant course was marked by multi-system organ failure and subsequent death within 48 h of injury. Polymicrobial cultures were with non-MDRO pathogens and were appropriately covered by the prescribed β-lactamase inhibitor combination agent.

Case 3

A 24-y-old was struck by a vehicle and was hemodynamically unstable on presentation with an open book pelvic fracture and a perineal injury. Concomitant resuscitation and operation included perineal debridement, Hartmann procedure, suprapubic cystostomy for urethral injury, and pelvic packing, followed by angiography with embolization of branches of the internal iliac artery because of ongoing instability. Examination during perineal debridement revealed an anterior anorectal injury that led to delayed abdominoperineal resection on post-injury day six to manage tissue necrosis. Despite multiple perineal debridements, the patient developed NSTI of the abdominal wall, perineum, and proximal right thigh. A staged ventral hernia of the abdomen was managed with split-thickness skin grafting. Severe perineal sepsis was managed by repeated washouts with packing of brown sugar followed by vacuum-assisted closure and subsequent local tissue flap transfer. Definitive pelvic stabilization was achieved on post-injury day 40. Despite multi-system organ failure complicated by systemic fungemia, the patient recovered and was discharged to rehabilitation three months after injury.

Discussion

Several common features contribute to the high mortality of this injury pattern. In each of the presented cases, the patients sustained substantial soft tissue injury secondary to severe crushing. Open book pelvic fracture led to hemorrhagic shock, tissue ischemia, and subsequent reperfusion injury. The initial tissue ischemia was exacerbated by angioembolization to control hemorrhage from internal iliac artery branches. Post-embolization tissue ischemic and fracture hematoma created an ideal environment for NSTI from the concentrated bacterial innoculum associated with anorectal disruption.

The management of open book pelvic fractures and associated hemorrhage has been reviewed [2]. Diminution of pelvic volume, either by temporary stabilization methods or external fixation, appears to be effective in managing venous hemorrhage [2]. Regardless of external reductions of internal pelvic volume, approximately 10% of patients manifest ongoing hemodynamic instability from arterial hemorrhage [2]. Although pelvic hemorrhage was classically managed by internal iliac artery ligation, current recommendations support early angioembolization [2]. Alternatively, pre-peritoneal packing may be done at the time of other procedures and is the only method that decompresses the contaminated pelvic hematoma in those with concomitant rectal injury [3]. Moreover, angioembolization predisposes the buttocks and perineum to ischemia. While the blood supply in the normal pelvis is well collateralized from the contralateral side, these collaterals may be disrupted in the setting of pelvic crush injury, further increasing infection risk.

Colon and rectal injuries account for only 30% of blunt hollow viscus injuries and 0.2% of blunt trauma admissions but manifest a complication rate of 30% [4]. Classic operative management of rectal trauma stems from wartime strategies, and involves a proximally diverting colostomy, creation of a distal stump with or without distal rectal washout. While repair of the rectal injury is not mandatory, if the injury is exposed at operation, debridement and repair is supported.

Although pre-sacral drainage has been advocated previously to obviate pelvic sepsis, this strategy appears to be used rarely [5]. In the cases presented, more aggressive initial surgical management of the rectal injury and associated pelvic contamination may have obviated subsequent NSTI. However, it is equally possible that distal rectal washout (without opening and debriding the pre-peritoneal space) may have more heavily contaminated the retroperitoneal and pre-peritoneal hematomas because of forcible evacuation of stool through the injury.

Last, an approach to perineal de-gloving injuries has been described [6]. In a landmark article by Kudsk et al. [6] in 1990, total diversion of the fecal stream with distal rectal washout, radical debridement of necrotic soft tissue, enteral access for nutritional support, and daily perineal debridement for at least five days obviated pelvic sepsis in patients surviving more than 48 h (12/18; 66%). Two patients died with an overall mortality of 44%. Pelvic fracture patients contained all the mortalities, with a mortality of 57% in those with pelvic fracture and perineal degloving. Only three patients surviving longer than 48 h had associated rectal injury, two of whom died, (mortality=66%) [6]. However, the management strategy supported by this article addresses only those who survive more than 48 h. In our small series, two of the three patients died within that time frame. Clearly, pelvic sepsis from open pelvic fracture portends a potentially poor outcome. A modified approach to complex open pelvic–perineal blunt injuries that includes vacuum-assisted closure management of the open wound has been reported and is similar to how our survivor was managed [7].

The management of difficult-to-debride wounds presents a unique challenge. Appropriate antibiotics, resuscitation, and nutritional support form therapy cornerstones for complex infections including NSTI. Mediastinal NSTI present resectional challenges in that much of the infected tissue often may not be debrided (e.g., myocardium). In this setting hyperbaric oxygen has been utilized to enhance bacterial killing as oxygen, in sufficient concentration, functions as an antibiotic. In addition, in settings in which surgical debridement is not immediately available or is problematic, honey and sugar packing is effective, as it was in our survivor [8]. Both agents create an osmotically unfavorable environment leading to bacterial dehydration and death. It is likely that such an environment disrupts biofilm by creating dessication and dehydration of the local ecology, and impedes quorum sensing functions [9].

An extensive review of NSTI diagnosis is coupled with a management guideline from the Surgical Infection Society [10]. This guideline recommends a return to the operating room within 24 h of initial debridement as one means of optimizing outcome. In comparison, our patients returned to the operating room earlier than 24 h, highlighting the aggressive nature of perineal and pelvic infection, the uniqueness of this patient population, and the current lack of sufficiently powered outcome data. Thus, this report is important in expanding and refining the extant body of knowledge regarding this uncommon constellation of injury and infection.

Conclusions

Pelvic crush resulting in open book pelvic fracture with hemodynamic instability and anorectal injury requires combination multimodal management. Early hemorrhage control, resuscitation, tissue debridement, and fecal stream diversion are durable approaches. Preperitoneal packing is an ideal hemorrhage control strategy and is the modality of choice for those with anterior rectal injuries, because it allows contaminated hematoma evacuation thus reducing infection risk. Infection management should embrace the use of adjuncts that aid in bacterial killing such as honey, sugar, and hyperbaric oxygenation because inadequately controlled pelvic sepsis portends a high mortality rate.