Biomechanical Comparison of Feline Coeliotomy Closure

Introduction:
Feline incisional herniation may occur more frequently in the caudal ventral abdomen. No specific recommendations for feline coeliotomy closure currently exist.

Materials and Methods:
Three regions of ventral abdominal wall in 16 cat cadavers were mechanically tested (n=48 samples). Pre-umbilical (PU), umbilical (U) and post-umbilical (POU) regions were harvested using a template. Linea alba thickness was recorded. Six samples without coeliotomy served as controls. Twenty-eight samples bisected on midline were randomized to suture bite stitch interval (SBSI) of 2x2 or 5x5 mm and suture material (2 metric polyglactin 910 or polydioxanone) for simple continuous coeliotomy closure. Fourteen samples were randomized to full-thickness or fascia-only closure. Samples were tested to failure by linear distraction. Tensile strength and mechanism of failure were recorded. Effects of body weight, linea alba thickness, anatomic region, SBSI, suture material and type of closure (full-thickness, fascia-only) were evaluated by mixed model linear analysis. Load to failure and mechanism of failure were compared between groups by independent t-test with P<0.05 considered statistically significant.

Results:
Mixed model analysis showed decreased load to failure of POU region and no difference between full-thickness and fascia-only closure. Failure most commonly occurred by tearing of suture through tissue. Suture failure (slacking) mainly occurred in 5x5 SBSI group.

Discussion/Conclusion:
The POU region of the ventral abdominal wall in cats is biomechanically weak, potentially predisposing this region to incisional herniation. We recommend 2x2 SBSI for caudal ventral coeliotomy closure in cats.