A Biomechanical Analysis of Prophylactic Mesh Reinforced Porcine Laparotomy Incisions

Abstract

Introduction: Research indicates that prophylactic mesh may help prevent incisional hernia after laparotomy, but best practice patterns in these situations are still evolving. Here, we compare the failure loads (FLs) and biomechanical stiffness (BMS) of 35 porcine abdominal wall laparotomy incisions reinforced with meshes of various widths and fixation distances using biomechanical testing.

Methods: In each specimen, a 10-cm incision was made and closed using continuous 1-0 Maxon suture. Specimens were randomized to mesh width (none, 2.5 cm, 3 cm, 4 cm, 6 cm, 8 cm) and tack separation (1.5 cm, 2 cm apart) and the meshes secured in an onlay fashion. Cyclic loads oscillating from 15 N to 140 N were applied to simulate abdominal wall stress, and the specimens subsequently loaded to failure. FLs (N) and BMS (N/mm) were comparatively analyzed.

Results: All specimens failed via suture pull-through. FLs and BMS were lowest in specimens with suture-only (421.43 N; 11.69 N/mm). FLs and BMS were significantly higher in 4-cm mesh specimens (567.51 N) than those with suture, 2.5-cm, and 3.0-cm mesh (all P < 0.05). FLs in specimens with a greater number of tacks were consistently higher in meshes of similar sizes, although these did not reach significance.

Conclusions: A 4-cm mesh reenforcement was superior to suture-only and smaller meshes at preserving strength in laparotomy closure in a porcine model but larger meshes (6 cm, 8 cm) did not provide an additional benefit. Meshes with more fixation points may be advantageous, but additional data are needed to make definitive conclusions.

Keywords: Hernia; Laparotomy; Mesh width; Prevention; Prophylactic mesh placement.

Fig. 1 –

Specimen following closure with running 1-0 Maxon suture.

Fig. 2 –

Specimen following mesh fixation with the Bard OptiFix tacker.

Fig. 3 –

Schematic breakdown of randomization of specimens to suture only, mesh width, and tacker distance.

Fig. 4 –

Representation of a specimen loaded and secured into the Instron prior to testing.

Fig. 5 –

Failure load of a baseline specimen, determined by peak of the extension versus load graph.

Fig. 6 –

Average failure loads in specimens secured with seven tacks per side.

Fig. 7 –

Average failure loads in specimens secured with nine tacks per side.

Fig. 8 –

Average failure loads in all specimens.

Fig. 9 –

Average biomechanical stiffness in all specimens.

Fig. 10 –

Average biomechanical stiffness in specimens secured with seven tacks per side.

Fig. 11 –

Average biomechanical stiffness in specimens secured with nine tacks per side.