Laparoscopic surgery is a minimally invasive technique using specialized instruments and small incisions to perform procedures within the abdominal cavity. This approach avoids the large incisions of traditional open surgery, leading to faster recovery times and less post-operative pain. However, any surgical incision creates a potential weakness in the body’s protective layers. A hernia is the protrusion of an organ or tissue through an abnormal opening in the body wall. The trocar site hernia (TSH) is a specific, though uncommon, complication where abdominal contents push out through the small incision made by a surgical port.
Understanding the Injury Mechanism
The mechanism of a trocar site hernia relates directly to establishing an access port into the abdomen. A trocar is a sharp instrument used to puncture the abdominal wall, allowing a cannula or sleeve to be placed as a working channel for surgical instruments. This penetration creates a defect passing through several tissue layers, including the skin, muscle, and the strong, fibrous fascia.
A TSH occurs when this fascial opening fails to close completely or heal with adequate strength after the cannula is removed. The constant outward pressure exerted by abdominal contents, especially during activities like coughing or straining, forces tissue into the unclosed gap. This allows intra-abdominal components, such as fat (omentum) or a loop of the small intestine, to push through the fascial defect and create the hernia sac.
The injury is fundamentally a localized incisional hernia. It results when the pressure inside the abdomen exceeds the holding capacity of the compromised fascial layer at the port site.
Recognizing the Symptoms
The most common symptom of a TSH is a noticeable lump or bulge directly underneath the skin at the former port site. This swelling often becomes more prominent when the patient stands, coughs, or strains, and may disappear when they lie down. The protrusion can be early-onset, appearing days after surgery, or late-onset, manifesting months or years later.
Localized pain or discomfort at the incision site is also frequent, often described as a dull ache that intensifies with physical exertion.
More concerning symptoms are associated with the incarceration or trapping of abdominal contents, particularly the bowel. If the hernia becomes trapped, patients may experience acute, crampy abdominal pain, nausea, and vomiting. This signals a medical emergency because the blood supply to the trapped tissue can be cut off, leading to tissue death.
Who is at Highest Risk
The risk of developing a trocar site hernia is influenced by surgical technique and the patient’s underlying health status. Surgical factors are primary determinants of risk, especially the size and location of the port. TSH is associated with the use of larger ports (10 millimeters or greater), which create a substantial fascial defect that is difficult to close effectively.
The umbilical area is particularly prone to hernia formation due to the natural weakness of the fascia in this region. Patient-specific factors create a high-risk profile by impairing wound healing and increasing intra-abdominal pressure. The true incidence of TSH is variable, estimated to be between 0.65% and 2.8% in many studies.
Risk Factors
Individuals face a higher risk if they have:
- A high Body Mass Index (BMI) of 30 kg/m\(^2\) or greater, as obesity causes increased pressure within the cavity and greater tension on the closure.
- Pre-existing conditions that compromise tissue repair, such as uncontrolled diabetes mellitus or malnutrition.
- Chronic conditions that cause frequent straining, such as Chronic Obstructive Pulmonary Disease (COPD) involving persistent coughing.
- Chronic constipation, which repeatedly stresses the healing fascial layer and contributes to defect formation.
Repairing the Hernia
Repair of a trocar site hernia is necessary to alleviate symptoms and prevent the serious complication of strangulation, where trapped tissue loses its blood supply. The surgical approach is chosen based on the size of the fascial defect and whether the hernia is new or recurrent.
For small defects, typically less than one centimeter, a primary closure technique is employed. This involves suturing the edges of the fascial defect together with strong stitches to restore the integrity of the abdominal wall.
For larger or recurrent hernias, the standard treatment involves a mesh repair. This procedure uses a piece of surgical mesh, a synthetic or biologic material, to reinforce the weakened area. The mesh is placed across the defect to provide a strong, permanent scaffold for new tissue growth, significantly reducing the chance of recurrence.
The repair can be performed using an open approach, which involves an incision directly over the hernia, or a laparoscopic approach. Laparoscopic repair uses instruments inserted through separate incisions, allowing the surgeon to place the mesh from inside the abdominal wall.