Trocar Site Hernia

Trocar site hernia is herniation of bowel, omentum or preperitoneal fat through the fascial defect left by the insertion of a laparoscopic trocar. Incidence is 0.5 to 3% overall, and up to 5% or more at the umbilicus. It is rare at 5 mm ports (under 1%).

Mechanism and risk

• Trocar diameter of 10 mm or more, particularly at the umbilicus and when the fascia is not closed
• Enlargement of a port for specimen extraction
• Cutting trocars, which leave a larger fascial defect than dilating trocars
• Prolonged operating time, repeated trocar manipulation and port site infection
• Obesity (BMI over 30), diabetes, smoking, older age, malnutrition and corticosteroid use
• Raised intra-abdominal pressure after operation (cough, vomiting, ileus)

Timing divides early-onset hernia (within 2 weeks, usually a Richter-type herniation of a bowel wall segment) from late-onset hernia (months to years, with omentum or a bowel loop). The Richter type produces obstruction or perforation without bowel dilatation and is easily missed. Strangulation occurs in a significant minority. Prevention by fascial closure reduces risk, and port closure is advised at all 10 mm or larger sites, and at 5 mm sites in children and in lateral or bladed ports.

• Early onset: increasing pain at a port site, nausea and vomiting, abdominal distension and low-grade fever 3 to 7 days after operation
• A tender swelling or erythema at the port site, or a wound that discharges
• Late onset: a bulge that appears on standing or straining
• Richter type: signs of local peritonitis, fever, normal bowel sounds, and passage of flatus despite strangulation
• Red flags: persistent postoperative pain beyond the expected course, tachycardia, vomiting, a tender irreducible lump and raised inflammatory markers

1. Clinical examination of every port site with the patient supine and standing, and with the Valsalva maneuver.
2. CT of the abdomen with intravenous contrast is the investigation of choice when the diagnosis is uncertain: a fascial defect with bowel or fat protruding, localized wall thickening, mesenteric stranding and free fluid in complications.
3. Ultrasound: a defect with a reducible or fixed sac and peristalsis.
4. Laboratory tests: white cell count, C-reactive protein, lactate and blood gases when strangulation is suspected.

Differentials: port site infection or abscess, hematoma, seroma, postoperative ileus, adhesive obstruction, port site metastasis, abdominal wall endometriosis.

Prevention (applies to every laparoscopic operation)

• Use dilating or bladeless trocars.
• Close the fascia at all 10 mm or larger ports and at sites with an extended incision, using a 0 absorbable suture on a fascial closure device.
• Evacuate pneumoperitoneum fully and remove ports under vision.

Early-onset or complicated hernia

• Nil by mouth, IV crystalloid 20 mL/kg initially, and nasogastric decompression if obstructed.
• Cefazolin 2 g IV and metronidazole 500 mg IV before operation, continued every 8 hours for 24 hours (up to 5 days if bowel is resected or contaminated).
• Urgent re-exploration, laparoscopic or open, through the defect. Reduce the contents, resect non-viable bowel, and close the fascia with 0 or 1 non-absorbable or slowly absorbable suture.
• Add mesh only in clean cases with a defect over 2 cm.
• Enoxaparin 40 mg SC once daily for 7 days.

Analgesia: paracetamol 1 g orally every 6 hours (maximum 4 g a day), with ibuprofen 400 mg orally every 8 hours with food for up to 7 days unless contraindicated.

Complications: recurrence, wound infection, mesh infection, enterotomy, and chronic pain.

Follow-up at 2 weeks and 6 weeks. Counsel on limiting lifting to under 5 kg for 4 weeks and on early return for increasing port site pain or vomiting.