Traumatic abdominal wall hernia and Morel-Lavallee lesion in a pediatric patient

Abstract

Traumatic abdominal wall hernias and abdominal Morel-Lavallee lesions rarely occur in blunt abdominal trauma. There are only a few documented cases of these occurring simultaneously, especially in the pediatric population. We report a case of a 15-year-old boy with a concomitant traumatic abdominal wall hernia and Morel-Lavallee lesions. Abdominal wall reconstruction was performed successfully via the collaboration of trauma, minimally invasive surgery, and plastic surgery teams.

A traumatic abdominal wall hernia (TAWH) is defined as a herniation through disrupted fascia and musculature without skin penetration or evidence of a prior defect after blunt trauma.¹ A similar type of injury that can occur in blunt abdominal trauma is a Morel-Lavalle lesion (MLL), in which a shearing force causes separation of the soft tissue from the fascia underneath. The most common anatomic locations for an MLL are the hips or thighs, and less commonly the abdominal wall.² We present a case of a TAWH and abdominal wall MLL occurring simultaneously after a motor vehicle crash in a pediatric patient.

CASE PRESENTATION

A 15-year-old obese boy presented to the emergency room after a motor vehicle crash. On arrival, he was unresponsive with weak femoral pulses. His systolic blood pressure was in the 100s and his heart rate was 135 beats/min, indicative of class III hemorrhagic shock. He was endotracheally intubated, and resuscitation was initiated with 2 units of both packed red blood cells and fresh frozen plasma. He had a seatbelt sign across the lower abdomen. A computed tomography (CT) scan showed significant intrabdominal injuries, including a jejunal bucket-handle injury, colonic hematomas, and bilateral grade V TAWHs, both containing bowel (Figure 1).³

Figure 1.

(a) Axial CT showing disruption of the right oblique muscles, with a hernia containing multiple loops of small bowel and colon extending into the adjacent subcutaneous tissue. (b, c) Axial images showing disruption of the inferior rectus muscles. (d) Sagittal view showing significant loss of rectus muscle. Together, these findings are consistent with a grade V traumatic hernia, defined as complete abdominal wall muscle disruption with herniation of abdominal contents.

The patient was taken to the operating room for exploration. Bilateral TAWHs and degloving injuries consistent with a MLL (Figure 2) were identified. The patient had extensive injuries to the right-side abdominal wall musculature involving the rectus abdominus, external abdominal oblique, internal oblique, transversus abdominis, and quadratus lumborum muscles. These injuries extended to the right psoas muscle and the muscle complex above the iliac crest to the 12th rib. Additionally, the left lower quadrant rectus muscle was transected along with the medial portion of the oblique muscles. Over the suprapubic area, there was loss and devitalization of the soft tissue and rectus muscle. Given their complexity in the setting of trauma and hemorrhagic shock, repair was deferred. A small bowel resection with anastomosis was performed for the bucket-handle injury. Retroperitoneal exploration was then performed to evaluate for further injuries, only noting a nonexpanding psoas hematoma. A temporary abdominal closure with an ABThera device was placed, and the patient was transferred to the intensive care unit for further resuscitation.

Figure 2.

Degloving injury plus muscle complex disruption of the (a) left and (b) right lower quadrant abdominal wall on initial exploratory laparotomy.

Two days later, the patient was brought back to the operating room for reexploration and abdominal wall reconstruction. The right-sided musculature was reapproximated en masse with #1 PDS sutures in a simple interrupted fashion. The left side musculature was reapproximated en masse with interrupted #1 PDS sutures in a figure-of-eight fashion. Reapproximation of the midline fascia was attempted, but there was significant tension. Therefore, a bilateral posterior rectus sheath release was performed to aid fascial closure. Despite this, there was still significant tension in the area of tissue loss. A 30 × 30 cm intraperitoneal Strattice mesh secured with multiple #1 PDS transfascial sutures was placed to reinforce the repair and bridge the area of tissue loss. Craniocaudally, the mesh extended from the xiphoid process to Cooper’s ligament. On the right side, the mesh extended through the previous retroperitoneal dissection down to the psoas muscle, while on the left side the mesh extended to cover the lateral extent of a left abdominal wall musculature repair (Figure 3a). The fascia superior and inferior to the area of suprapubic tissue loss was reapproximated with #1 PDS sutures in a continuous fashion. The fascia in the area of suprapubic tissue loss could not be approximated without tension. The skin was not closed, and a 3M Vacuum Assisted Closure (V.A.C.) Ulta Therapy System was then applied.

Figure 3.

(a) Post–abdominal reconstruction with a bridged biologic mesh. A pedicled anterolateral thigh flap based on the descending branch of the lateral circumflex artery was tunneled under the rectus femoris muscle to reach the defect. The venous congestion resolved over time, and the flap provided durable soft tissue coverage with the thigh donor site closed primarily. Anterolateral thigh flap: (b) open wound, (c) flap creation, and (d) final repair.

Multiple subsequent bedside V.A.C. changes were performed. Surprisingly, the patient did not have a large amount of delayed skin necrosis and only required bedside debridement. The wound was partially closed 2 to 3 weeks later. At that time, granulation tissue was forming in the wound bed around the biologic mesh (Figure 3b). A CT scan 1 month after hernia repair showed no evidence of recurrence (Figures 4a–e). Two months after his index operation, the patient underwent a pedicled anterolateral thigh flap to cover the mesh (Figures 3b–d). No complication related to the hernia repair has occurred (Figure 4f). The patient was discharged to a rehabilitation facility after 62 days in the hospital.

Figure 4.

(a–e) Axial CT images obtained approximately 1 month after the index operation demonstrating traumatic hernia repair and an associated abdominal wall defect. (f) Coverage of the abdominal wall defect with an anterolateral thigh flap.

DISCUSSION

TAWH and MLLs of the abdomen are rare. TAWHs are well characterized by Harell et al. Given the limited current literature, there is not strong evidence for treatment algorithms. While early repair of TAWHs appears to be safe with low complication rates, there is still debate on the type of repair, the timing of repair, and the necessity for mesh use.¹ Due to the emergency setting and inability to obtain total fascia closure, we elected to perform a repair with biologic mesh to restore abdominal wall functionality. We chose biologic over synthetic mesh due to contamination, increased infection risk, and bridging requirement.^4,5 We elected not to do a component separation, as it could have also increased his risks for wound complications significantly.^6–8 Delayed primary closure of the skin was performed to reduce wound burden, while leaving the area of tissue loss open for continued assessment.⁹ The anterolateral thigh muscle flap was chosen because it provides a large amount of muscle and some of the resilient deep fascia of the lateral thigh, which can provide strong coverage of our abdominal wall defect. This flap has been combined with bioprosthetic mesh previously to reconstruct large sections of the anterior abdominal wall with success.^10,11 The presence of the flap will, however, influence the approach and extent of future abdominal surgeries, with preferentially minimally invasive approaches or incisions/techniques that avoid the devitalization of the flaps, as well as a multidisciplinary approach with an abdominal wall surgeon and plastic surgeon.