Surgical Repair of Indirect Inguinal Hernia in Bonnet Macaque (Macaca radiata)

Hernia is a protrusion of an organ from the wall of the cavity bearing it. This condition usually involves the organs omentum, adipose tissue, and intestinal loops. Inguinal hernia is a type of hernia wherein such contents protrude through a weak area in the lower abdominal wall. Inguinal hernias can be classified as direct or indirect hernia. These are common in primates and asymptomatic hernias generally do not need repair. However, inguinal hernias have been reported in several monkey species. Indirect inguinal hernia has been observed particularly in nonhuman primates; mainly in macaques as well as in baboons.

This study reports a rare case of indirect inguinal hernia. It accounts for the omentum engaged in scrotum through the hernial ring in a bonnet macaque as well as its surgical management.

A 19-year-old male bonnet macaque was presented with distension of the right inguinal and scrotal region. The researchers conducted a physical examination that revealed an inguinal hernia. Surgical intervention was then deemed necessary considering the state of the animal. The herniation was surgically corrected by the removal of the protruded fatty mass. The monkey was also kept in strict confinement until complete healing. After two weeks, the animal recovered without any post-operative complications.

Overall, this case details a successful surgical repair of an indirect inguinal hernia in a bonnet macaque.

In this study, the animal was asymptomatic initially which may be due to the presence of non-incarcerated omentum. This  accounts for the asymptomatic and benign nature of inguinal hernia. Inguinal hernias are treated surgically either using suture-repair or mesh-repair techniques. This case was successfully attempted with suture-repair technique. In veterinary practice, management of the hernial content by suturing the hernial ring is common regardless of body size; whereas herniation in large animals usually requires meshes. Depending on bowel strangulation, severity of inguinal hernia varies from benign to extreme emergency.

Based on this case study, it was concluded that surgery can be an ideal and effective option for the treatment of inguinal hernias in primates.

This  study also gathered that the case of inguinal hernia should be given conventional medicines in initial stages to cope with clinical signs and symptoms. But in case of no improvement, surgical intervention after proper diagnosis is recommended. As observed in this study, surgery can be an ideal and effective solution for the treatment of inguinal hernias in primates. However, postoperative care can be a challenging task in macaques because of possible site manipulation. Regular checkup then should be done to ensure proper healing. For future research, epidemiological studies on inguinal hernia’s prevalence in non-human primates is recommended.