Trocar site hernias (TSH) tend to develop more frequently – around 25% of them – at umbilical and midline port sites due to a natural weakness of the linea alba. Most hernias develop in the first month after surgery, especially during the first 10 days. About 70-80% of trocar site hernias require surgical management and one of the most feared complications of trocar site hernias is small bowel strangulation. Ritcher’s hernia is particularly frequent in TSH. It is defined by a protrusion of the antimesenteric wall of the intestine through a defect in the abdominal wall, so it can cause small bowel strangulation without causing obstructive symptoms. The incidence of Ritcher’s hernia reaches 47.6% in early onset TSH.
About 80-90% of trocar site hernias occur at incisions that are 10 mm or larger, so an incision size larger than or equal to 10 mm is a significant risk factor.
Other associated risk factors are:
- – prolonged surgical time
- – manipulation of the incision
- – number of trocars
- – incomplete closure of fascia at the trocar site
- – midline trocars
- – organ retrieval through the trocar site
- – partial vacuum during port withdrawal, drawing the omentum and intestine into the fascial defect
- – wound infection at trocar site
- – reinsertion of the port
- – host factors: obesity, poor nutrition, advanced age, gender, diabetes, steroid therapy
The clinical presentation of TSH is variable, as is the time of onset. Usually, it presents as swelling and pain at the incision site and may be hard to differentiate from a hematoma or wound infection, especially in the first post-operative days. Especially in obese patients, diagnosis by physical examination can be tricky, so CT scans can be helpful.
Careful postoperative management is recommended, especially in patients with the risk factors mentioned. Bowel occlusion is often insidious, as in the case of a partial Richter’s hernia, which typically presents with vomiting or nausea and a distended and painful abdomen, especially in the first 14 days after surgery. When resolution of postoperative ileus after laparoscopic surgery is not achieved after 7–14 days, a differential diagnosis with mechanical occlusion should be obtained by means of a CT scan.
TSHs are classified into 3 types, originally described by Tanouchi:
Type 1, early-onset: indicates dehiscence of the anterior fascial plane, posterior fascial plane, and peritoneum. It often presents as a small-bowel obstruction.
Type 2, late-onset: develops several months after surgery and is frequently related to complications of the trocar insertion. It indicates dehiscence of the anterior fascial plane and posterior fascial plane. The hernia sac of the late-onset type is in the peritoneum.
Type 3, special type: indicates dehiscence of the whole abdominal wall, with protrusion of the intestine and other tissue (eg, greater omentum).
Trocar site hernias are directly related to the size of the trocar, being more common at > 10mm sizes rather than in 5mm. Therefore, it is recommended that all incisions > 10mm be closed, if possible. When active manipulation through a 5-mm port has occurred during prolonged procedures, the fascial defect should be closed to avoid complications. Many authors have recommended the deflation of the pneumo-peritoneum prior to port removal, so the omentum and intestines are not drawn into the fascial defect.
According to most authors, despite the evidence that some types of trocars or incisions may prevent or are better at avoiding trocar site herniation, closure of both the fascia and the peritoneum should be performed when possible.