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Delayed laparoscopic repair of a traumatic flank hernia: A case report and review of the literature

Highlights • Not all traumatic abdominal wall hernias require laparotomy at time of injury.• Observation is considered to be safe when there is no other indication for surgery.• Many patients managed non-operatively remain asymptomatic.• Delayed laparoscopic repair with mesh reserved for hernias that become symptomatic.


Introduction
The traumatic abdominal wall hernia (TAWH) is an acquired defect resulting from the disruption of the abdominal wall musculature due to trauma. There is a lack of consensus on the appropriate management of the TAWH despite it first being described by Selby in 1906 [1]. This is likely because TAWHs are uncommon affecting less than 1% of traumatically injured patients [2][3][4]. With the ubiquitous use of computed tomography (CT) in the evaluation of trauma patients, surgeons more often must make decisions on the treatment of TAWHs at the time of injury. Several retrospective studies have provided a better understanding of their clinical significance. Nevertheless, the appropriate management of TAWHs remains unclear. We present a patient with a TAWH who underwent delayed laparoscopic repair with mesh and suggest a management strategy based on a review of the literature. This work has been reported in line with the SCARE guidelines [5].

Presentation of case
A 43-year-old male was evaluated in clinic for a left flank bulge. He was involved in a motorcycle collision (MCC) eight months prior with fractures of the left acetabulum and femur and a TAWH (Fig. 1). He had no associated intra-abdominal injuries. The patient required operative treatment of his orthopedic injuries and was ultimately discharged to home. He noticed an abdominal bulge two months after his MCC that progressively worsened in size and in discomfort. On physical examination, he had a reducible left flank hernia. CT showed an enlarging left flank hernia involving colon and small intestine (Fig. 2). Due to his symptoms, elective repair was offered to the patient and he decided to proceed with surgery. Laparoscopic repair with synthetic mesh was performed. Operative steps included reduction of the hernia sac, mobilization of the descending and sigmoid colon, retroperitoneal dissection defining the boundaries of the defect, and wide synthetic mesh overlap of the defect (Fig. 3). The defect measured 12 cm × 6 cm (Fig. 4).   tacks. The fascial defect could not be closed (Fig. 5). The patient's postoperative course was uneventful and there was no recurrence at 3 years.

Discussion
TAWHs typically result from high-energy blunt trauma such as motor vehicle collisions and MCCs although they have been described in low-energy blunt trauma as with bicycle handlebar injuries [6]. The mechanism of injury involves rapid deceleration with tangential shearing forces to the abdominal musculofascial structures and an acute rise in intra-abdominal pressure [7,8]. TAWHs may be further classified based on the affected muscle group with anterior abdominal involving the rectus abdominis, flank involving the oblique muscles, and lumbar occurring in the superior and/or inferior lumbar triangles [3]. The presence of concomitant intra-abdominal injuries can complicate the timing and the technique of hernia repair. Additionally, surgical repair is made more challenging in traumatic flank and lumbar hernias due to their lateral location, proximity to bony structures, and the general lack of healthy tissue for primary closure and/or mesh fixation [8].
Historically, exploratory laparotomy was considered mandatory at the time of diagnosis for all high-energy TAWHs due to a highpercentage of associated intra-abdominal injuries. This is no longer thought to be necessary. There is an increasing trend towards initial observation of TAWHs that do not have a clear indication for operative intervention at time of injury such as hemodynamic instability or peritonitis. This is inclusive of some TAWHs with associated intra-abdominal injuries, specifically solid organ injuries. Studies have shown that these patients may be safely observed with very few expected to fail non-operative management and go on to require surgery in the acute post-traumatic period [3]. And while it was previously argued to repair TAWHs immediately due to a 25% risk of incarceration and a 10% risk of strangulation; more recent studies demonstrated greater than 70% of TAWHs being managed non-operatively with few to no patients developing complications related to the hernia necessitating repair [3,4].
Retrospective studies have shown that TAWHs undergoing delayed repair have fewer perioperative complications and a decreased recurrence rate [2,4]. This may be due in part to the patients that undergo immediate repair more commonly have associated intra-abdominal injuries and require laparotomy; some of which are performed in a damage control fashion. Additionally, primary closure of acutely traumatized musculofascial structures is suboptimal and the use of synthetic mesh is often limited due to intra-abdominal contamination. A recent study suggested that patients with a TAWH undergoing immediate surgery have either no intervention or placement of biologic mesh and evaluation at a later date for possible definitive hernia repair [3]. This was based on the improved outcomes they found in the TAWHs undergoing delayed repair.
There are no definitive recommendations on the technique for TAWHs undergoing delayed repair, but a laparoscopic approach has been shown to be safe and to have several advantages when compared to open surgery. Laparoscopic repair of TAWHs is associated with a shorter hospital length of stay, decreased postoperative pain and consumption of narcotics, and earlier return to normal activities [8,9]. Similar to what is reported in the literature, our patient was appropriate for discharge to home on postoperative day two and returned to work two weeks after surgery. As with ventral hernia surgery, the use of synthetic mesh in TAWH repair is recommended to decrease the risk of recurrence. Furthermore, just as we found in our patient, mesh placement is often necessary to cover a large fascial defect in a location that often lacks healthy soft tissue to perform a tension-free primary closure.

Conclusion
Despite the high-percentage of concomitant intra-abdominal injuries, there is growing evidence that supports a non-operative management strategy in patients with a traumatic abdominal wall hernia and no clear indication for abdominal surgery at time of injury. Based on our experience and review of the literature, these patients may be safely observed with delayed laparoscopic repair using synthetic mesh reserved for the traumatic abdominal wall hernia that becomes symptomatic.

Conflicts of interest
No conflicts of interest.

Funding
No sources of funding.

Ethical approval
This work is exempt from ethical approval.

Consent
Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Author's contribution
Mead Ferris performed a review of the literature, wrote, and edited the paper. Christopher Pirko performed a review of the literature, wrote, and edited the paper. James Nottingham edited the paper.