Massive traumatic abdominal wall hernia with significant tissue loss: challenges in management

Abstract

A 41-year-old woman presented to our trauma centre following a high-speed motor vehicle collision with a seatbelt pattern of injury resulting in extensive rupture of her abdominal wall musculature and associated hollow viscus injuries. The abdominal wall had vertical separation between transected rectus, bilateral transverse abdominis and oblique muscles allowing evisceration of small and large bowel into the flanks without skin rupture. Intraoperatively, extensive liquefaction and tissue loss of the abdominal wall was found with significant retraction of the remaining musculature. Initial operative management focused on repair of concomitant intra-abdominal injuries with definitive repair performed in delayed, preplanned stages including bridging with absorbable mesh and placement of an overlying split-thickness skin graft. The patient was discharged from hospital and underwent extensive rehabilitation. One year later, the abdominal wall was definitively repaired with components separation and biological mesh underlay. This stepwise repair process provided her with a robust and enduring abdominal wall reconstruction.

Background

Traumatic abdominal wall hernias (TAWHs) are an uncommon, but morbid, consequence of blunt torso trauma,¹ occurring in approximately 1% of cases.² Typically, TAWHs arise as a result of direct trauma to the abdominal wall from deceleration forces, such as those transmitted by a seatbelt, leading to increased intra-abdominal pressures which ultimately cause disruption of the wall.³

TAWHs can be challenging to diagnose on physical examination alone as there is often no reducible bulge. The hernia can also be difficult to visualise as it is often covered by ecchymosis.¹ Thus, most TAWHs are diagnosed with a CT scan.⁴ Rupturing the abdominal wall requires significant force, and nearly 90% of patients with TAWHs have associated intra-abdominal injuries,⁵ with bowel involvement in 50% of cases.⁶ Patients with TAWHs require an average of 2.1 operations.⁵

The literature regarding TAWHs is relatively limited. Given this, and the heterogeneous nature of TAWHs, they are managed with a variety of techniques based on factors related to the patient’s overall injury burden, the size/location of the hernia and surgeon preference.^7–14 Since concomitant intra-abdominal injuries are common, the initial management priorities focus on control of haemorrhage and contamination.^{15 16} In many cases, the patient’s physiology mandates a damage control approach which may preclude reconstruction of gastrointestinal organs and the abdominal wall.¹⁷ Additionally, reduction of abdominal contents and a tension-free fascial closure is often impossible during the initial operation due to visceral oedema and abdominal wall muscle loss or retraction.¹⁷ Thus, approximately 10%–15% of patients with severe abdominal trauma are treated with an open abdomen and a temporary closure following trauma laparotomy.^{15 17 18}

This case of a devastating TAWH in a patient with multiple intra-abdominal injuries highlights many of these crucial surgical considerations. The surgical team prioritised the life-threatening injuries and then addressed the TAWH in a stepwise manner to optimise the repair.

Case presentation

A 41-year-old woman with body mass index 20.1 was involved in a high-speed motor vehicle accident. She was a rear-seated, restrained passenger, in a head-on collision travelling at approximately 80–100 km/hour. Her medical history was unremarkable.

She was initially assessed at a peripheral hospital where she was resuscitated. She was transferred to our level 1 trauma centre by air ambulance. On arrival, she was tachycardic (heart rate 122 beats per minute (bpm)), but her other vitals were within normal limits. On examination, the patient’s abdomen was tender but non-peritonitic and an extensive 3-point seatbelt pattern injury was apparent across her lower abdomen and chest with an associated large left breast haematoma. Although the ecchymosis at the seatbelt injury was extensive, the skin itself was intact. Her chest and pelvic X-rays showed no obvious pathology aside from the left-sided opacity corresponding to the chest wall haematoma. The focused assessment with sonography for trauma scan was negative for intra-abdominal fluid.

She was transferred to the CT scanner (findings described under the Investigations section), which revealed injuries consistent with an Injury Severity Score of 34. Shortly after the CT scan, she became increasingly tachycardic (heart rate 130 bpm) and her systolic blood pressure decreased to 76 mm Hg. She was resuscitated with blood products and crystalloids and taken urgently to the operating room for a trauma laparotomy.

Investigations

Her admission imaging included CT scans of the head, spine, chest, abdomen and pelvis, and lower extremities, CT cystogram, and CT angiogram of the head and neck (figure 1). Her injuries were as follows:

Figure 1.

Contrast enhanced axial (A) and coronal CT images (B) acquired as part of the initial trauma evaluation demonstrate extensive disruption of the anterior and lateral abdominal wall musculature.

1. Diffuse axonal injury.

2. Cervical-spine ligamentous injury.

3. Bilateral carotid dissections.

4. Right internal jugular vein thrombus.

5. Left brachial plexus injury.

6. Bilateral hemo/pneumothorax.

7. Left chest wall haematoma.

8. Left pulmonary contusion.

9. Anterior mediastinal haematoma.

10. Multiple rib fractures.

11. Significant abdominal wall disruption with evisceration but intact skin (details below).

12. Small bowel perforation.

13. Transverse process fractures of lumbar spine vertebrae 1 and 2.

14. Right common iliac artery dissection flap.

With respect to the abdominal wall, there was frank rupture of the musculature with vertical transection of the rectus muscles. There was a transverse plane tear extending laterally through both the bilateral transverse abdominis muscles and oblique muscles which separated vertically. Both large and small bowel protruded through the defect about which there was adjacent inflammatory stranding. Surface rendering demonstrated no dermal discontinuity. Thus, there was evidence of evisceration injury without skin surface rupture (figure 2).

Figure 2.

Three-dimensional surface rendering (A) demonstrates a lack of disruption of the skin surface, while a fat subtracted three-dimensional surface rendering (B) demonstrates the vertical separation of the abdominal wall musculature and protrusion of bowel through the defect.

Treatment

Bilateral chest tubes were placed prior to laparotomy. Given the known abdominal wall disruption, the abdomen was entered cranial to the defect. A small amount of haemoperitoneum was encountered but there was no ongoing haemorrhage. There was a significant bucket-handle injury of the small bowel mesentery with a 25 cm devascularised segment of bowel which was resected. Due to the damage control nature of the initial surgery, the bowel was left in discontinuity. Bilateral diaphragmatic injuries were identified. They did not involve the intercostal muscles of the thoracoabdominal wall. The diaphragms were repaired primarily.

Assessment of the abdominal wall revealed extensive full thickness disruption below the level of the intact skin. Ecchymoses and abrasions were evident in the pattern of the lap belt across the lower abdomen. Under the length of the seatbelt pattern, the underlying fat was partially liquified, and necrotic and significant portions were avulsed from the remaining superior and inferior abdominal wall musculature which appeared devascularised. There was a full thickness transection of this abdominal wall musculature extending to the quadratus lumborum on the right side and halfway up the pelvic brim on the left side. The adjacent superior and inferior abdominal wall musculature were retracted above the umbilicus and to the level of the pubis, respectively.

Given the extensive disruption, all necrotic tissue was debrided but no attempt to reapproximate the fascia was feasible. Portions of the peritoneum overlying the lateral wounds were closed and packed with sponges in order to decrease the risk of visceral incarceration, and temporary abdominal closure with a closed suction device was carried out.

Her vascular injuries were initially treated with intravenous heparin which was subsequently transitioned to warfarin under the guidance of the vascular surgery team. The patient did not experience adverse bleeding events during her hospital course.

She further underwent two washouts and a small bowel anastomosis. An initial attempt at fascial closure was delayed by anastomotic dehiscence and worsening haemodynamic instability. The anastomotic dehiscence was resected to proximal, healthy bowel which was used to fashion an ileostomy. Due to the extensive soft tissue loss, there was no suitable way to reconstruct the abdominal wall primarily. Where previously the peritoneum alone had been reapproximated, a biological porcine dermis-derived mesh (Strattice) was secured between the lateral abdominal wall musculature and attachments to the iliac crest. This was done to further prevent visceral herniation pending a definitive repair. At a later operative procedure, the large midline defect was bridged using polyglactin 910 (Vicryl) mesh.

After healthy granulation tissue had covered the entire Vicryl mesh, the patient received a split-thickness skin graft over the entirety of the abdominal wall defect. In total, the patient underwent seven surgeries (six laparotomies and one skin graft) during her admission.

One year after her motor vehicle collision, the patient was brought back to the operating room for definitive management of her TAWH and ileostomy reversal. On the left side, a rectus abdominus flap was developed. This could not be done on the right side due to tissue loss, so a transversus abdominus release was performed which provided an additional 10 cm of mobilisation. Unfortunately, that was still not enough to bring the right rectus to midline. Subcutaneous flaps were developed bilaterally, and the anterior rectus sheath freed up to provide several additional centimetres of medial mobility. A large piece of Strattice mesh was placed in an underlay fashion with suitable fascial coverage over much of the incision. However, in the lower abdomen, where there had been substantial tissue loss, overlying musculofascial closure was not possible. For this portion of the TAWH, approximately 8×7 cm Strattice mesh was secured in an underlay fashion with suitable circumferential overlap of the surrounding fascia. The patient’s further postoperative course was unremarkable.

Outcome and follow-up

The patient has recovered well from an abdominal wall perspective. The major driver of her disability continues to be the associated brachial plexus injury.

Discussion

The literature to guide repair of TAWHs is relatively sparse, but there are several overarching principles that we were able to follow. After repair of any intra-abdominal pathology and resolution of other life-threatening injuries, the priority becomes abdominal closure.¹⁹ Surgical planning for closure involves several important decisions, the first of which is timing. The World Society of Emergency Surgery guidelines suggest that closure should be attempted as soon as possible, once resuscitation has completed, source control is achieved and there is no plan for re-exploration, such as concern for intestinal viability.²⁰ If abdominal closure is not completed within 5–7 days, it is unlikely to happen at the index admission.²¹ It has been demonstrated that early repair decreases incidence of bowel obstruction and incarceration.⁸ However, mortality and fistula formation is not different based on timing of abdominal closure at 9 days²² and even up to 6 months.⁹ The timing of the repair does not seem to impact the likelihood of hernia recurrence.⁸ Therefore, the timing of definitive TAWH repair should be individualised and take into account multiple factors including the patient’s other injuries, physiological status and abdominal wall anatomy.

While the abdomen is open, temporary closure devices are used to protect the intra-abdominal contents from contamination and dehydration. These devices typically apply negative pressure and have been demonstrated to simplify nursing care and prevent intra-abdominal adhesions.²³ They have not demonstrated increased enterocutaneous fistula rates, even in the presence of anastomosis when protected by omentum.^{24 25} Furthermore, negative pressure devices increase the likelihood of fascial closure at 21 days.²⁵

At definitive closure, the surgeon must determine whether to use mesh and if so what type of mesh is most appropriate. Mesh can safely be used in the absence of gross contamination²⁶; however, if there is concern for contamination, the use of mesh is controversial.¹¹ Surgeons must balance the lower recurrence rates accrued by mesh versus the danger of an infected mesh.¹¹ In a meta-analysis, 70% of TAWH recurrences occurred in patients without mesh augmentation.⁸ One case series described no recurrences in patients with mesh repairs,⁵ while another found that non-mesh repairs failed in most patients.¹⁰ Multiple authors have advocated for mesh use in all patients with delayed repair of TAWH.^{11 27} Several types of meshes, including synthetic and biological, have been used in the treatment of TAWH, and there does not seem to be consensus on the optimal type.^{12–14 28}

If early closure of overlying fascia is not possible, absorbable meshes are often used for closure to prevent evisceration. In time, granulation tissue grows over the mesh as the wound heals by secondary intention. Once granulation coverage is complete, a skin graft is performed.^{29 30} Finally, many months later, definitive repair of the ventral hernia may be attempted. A minimum delay of 6 months is suggested to enable abdominal adhesions to mature, allowing for safe dissection of the skin graft off the bowel.³¹

In cases of extreme abdominal wall tissue destruction, it may not be possible to perform a tension-free repair that reapproximates facial tissue. The components separation strategy can be used at the definitive operation to further medialise the abdominal wall and facilitate closure.²⁰ Still, if the tissue is inadequate to completely cover the abdominal contents despite all achievable mobilisation, as in our case, the use of a mesh to provide coverage of the remaining defect and prevent visceral incarceration is an acceptable method for hernia repair.

This was an especially challenging case of TAWH for several reasons. First, the TAWH itself was grade V as there was completed abdominal wall muscle disruption with herniation of abdominal contents.² Additionally, the patient had significant intra-abdominal injuries that required immediate management. Her initial haemodynamic instability was likely the result of a combination of factors including any external blood loss at the scene, the large breast and chest wall haematoma, a small amount of intrathoracic blood and the small bowel mesenteric injury. Collectively, her multisystem injuries, abdominal wall tissue loss and intermittent instability necessitated temporary abdominal closure at the initial operation. The length of time with a temporary closure device was extended by the anastomotic leak. During this time, the abdominal wall further retracted resulting in extensive loss of domain. Because of these factors, our surgical team had to employ several strategies (delayed, stepwise repair, components separation, mesh underlay) to achieve definitive repair. Fortunately, this combined approach produced a functionally and cosmetically acceptable outcome for the patient.

Learning points.

• Repair of traumatic abdominal wall hernia (TAWH) can be challenging, especially when there is destructive injury to the abdominal wall, with many important surgical considerations such as repair timing and the use of mesh.

• Repair must be tailored to the injury encountered. Surgeons may need to employ multiple strategies to optimise the restoration of normal anatomy.

• TAWH repair may be best performed in a delayed, staged fashion once intra-abdominal injuries are repaired and the patient’s physiological status is optimised.