Biomechanical properties of feline ventral abdominal wall and celiotomy closure techniques

OBJECTIVE To compare biomechanical properties and mechanism of failure of 3 regions of ventral abdominal wall in cats by using 2 suture materials, 2 suture bite-to-stitch intervals (SBSI), and full-thickness versus fascia-only closure. STUDY DESIGN Randomized, cadaveric, ex vivo mechanical testing. SAMPLE POPULATION 16 adult cat cadavers, 3 samples per cat. METHODS Three regions of ventral abdominal wall were mechanically tested (N = 48 samples). Preumbilical, umbilical (U), and postumbilical (POU) regions were harvested by using a template. The thickness of the linea alba was recorded. Six samples without celiotomy served as controls. Twenty-eight samples were randomized to SBSI (2 × 2 or 5 × 5 mm) and suture material (3-0 polyglactin 910 or 3-0 polydioxanone) for simple continuous celiotomy closure. Fourteen samples were randomized to full-thickness or fascia-only closure. Samples were tested by linear distraction; tensile strength and mechanism of failure were recorded. Effects of body weight, thickness of linea alba, anatomic region, SBSI, type of closure, and suture material were evaluated by mixed model linear analysis. Load to failure was compared between males and females, full-thickness and fascia-only closure by independent t test, with P < .05 considered statistically significant. RESULTS The POU region achieved lower loads to failure. Load to failure was greater in males compared with females. No difference was detected between full-thickness and fascia-only closure. Failure most commonly occurred by tearing of suture through tissues. Tissue failure with suture line loosening occurred mainly in the 5 × 5-mm SBSI group. CONCLUSION The POU region is biomechanically weak and may therefore be predisposed to incisional herniation.