Does the angle of trocar insertion affect the fascial defect caused? A porcine model.

Introduction: With an incidence of 0-5.2%, trocar site hernias frequently occur following laparoscopy. It is unclear to what extent the angle of trocar insertion affects the size of the fascial defect caused. Hence, we performed a porcine model.

Methods: In October 2022, a total of five female pigs were euthanized. In alternating order, three bladeless and two bladed conical 12-mm trocars were inserted at an angle of 45° on each side for 60 min twice each pig. For this purpose, an epoxy resin handmade cuboid with a central channel that runs at an angle of 45° was used. Subsequently, photo imaging and defect size measurement took place. The results were compared with those of our previously conducted and published porcine model, in which the trocars were inserted at an angle of 90°. Effects of trocar type (bladed vs. bladeless) and angle on defect size were analyzed using a mixed model regression analysis.

Results: The bladeless trocars caused statistically significant smaller defects at the fascia than the bladed (23.4 (SD = 16.9) mm vs. 41.3 (SD = 14.8) mm, p < 0.001). The bladeless VersaOne trocar caused the smallest defect of 16.0 (SD = 6.1) mm. The bladed VersaOne trocar caused the largest defect of 47.7 (SD = 10.5) mm. The defect size of the trocars used at a 45° angle averaged 30.5 (SD = 18.3) mm. The defect size of trocars used at a 90° angle was significantly larger, averaging 58.3 (SD = 20.2) mm (p = 0.007).

Conclusion: When conical 12-mm trocars are inserted at a 45° angle, especially bladeless ones, they appear to cause small fascial defects compared with insertion at a 90° angle. This might lead also to a lower rate of trocar hernias. Bladeless trocars might cause smaller fascial defects than bladed trocars.