Repair of a Large Ventral Hernia in a Rhesus Macaque (Macaca mulatta) by Using an Abdominal Component Separation Technique

Abstract

Here we present a 32-y-old rhesus macaque (Macaca mulatta) with a large recurrent ventral incisional hernia. The initial surgery included midline celiotomy for treatment of endometriosis, in which the animal developed a hernia that was repaired with interposition of mesh. Hernia recurrence at 1 y resulted in a defect measuring 7 × 13 cm, with loss of abdominal domain. Skin breakdown was noted with areas of exposed mesh through the skin with associated acute on chronic infection. Clinically, the animal was lethargic, not eating, and failing to thrive. The present surgical treatment included midline celiotomy, removal of mesh, and attempted primary fascial closure. Due to the large defect and high tension, the fascia could not be closed. To facilitate closure, abdominal component separation technique was used and consisted of skin and subcutaneous dissection, external oblique muscle release, and dissection between the external and internal oblique musculature. This technique allowed for primary fascial closure and resection of excess diseased skin. A piece of polypropylene mesh was placed in a sublay fashion to reinforce the primary fascial closure. The animal tolerated the procedure well and has demonstrated steady weight gain, with no recurrence at 12 mo. Large ventral abdominal hernia defects in after surgery or trauma in NHP can present reconstructive challenges to veterinary surgeons. Failure to achieve a dynamic, low-tension closure can result in hernia recurrence, necessitating additional operations. Abdominal component separation is not commonly used in veterinary surgery and may be a helpful tool in cases of difficult abdominal reconstructions.

Figure 1.

Diagram of a hemiabdominal wall defect in the axial plane, outlining the operative steps of component separation of parts. Step 1; release of subcutaneous tissues to anterior axillary line. Step 2: release of the external oblique muscle. Step 3: dissection between the internal oblique and external oblique muscles to the anterior axillary line. Reproduced with permission from reference 1.

Figure 2.

Prerepair photo of large incisional hernia defect in the abdominal wall; the macaque is supine on the operating table. Note the skin breakdown and extrusion of previous placed mesh.

Figure 3.

Intraoperative photo of hernia fascial defect after removal of old mesh and lysis of adhesions. Hernia measures 7 cm wide by 13 cm craniocaudally.

Figure 4.

Intraoperative photo of component separation. This photo demonstrates the elevation of the skin and subcutaneous tissue off the left hemiabdominal wall and incision of the external oblique aponeurosis at 1 cm lateral to the linea semilunaris from the costal margin to the inguinal ligament (dotted line). The internal oblique muscle and aponeurosis can be visualized under external oblique aponeurosis. The same procedure was performed on the right hemiabdominal wall.

Figure 5.

Intraoperative photo of component separation. This photo demonstrates the left hemiabdominal dissection between the external oblique aponeurosis and muscle and in the internal oblique aponeurosis and muscle to the anterior axillary line. The same procedure was performed on the right hemiabdominal wall.

Figure 6.

Intraoperative photo of mesh sublay prior to primary fascial closure. The mesh was placed beneath the rectus muscle and sutured to the undersurface of the abdominal fascia.

Figure 7.

Intraoperative photo of primary fascial closure over a polypropylene mesh underlay by using 2-0 polydiaxanone suture. Note the fascial advancement due to left hemiabdominal wall component separation (dotted line).

Figure 8.

Intraoperative photo of tension-free closure after resection of nonviable skin.

Figure 9.

Algorithm for reconstruction of large hernias in NHP.