Inter- and intraindividual variabilities of perforation forces of human and pig bowel tissue

Background: A laparoscopic bowel grasper should be suitable for safely grasping the bowel in a wide variety of patients. Therefore, the inter- and intraindividual variabilities in the strength of bowel tissue to resist perforation force should be analyzed. Methods: The large and small bowels of pigs (n = 14) and the human small bowel (n = 7) were clamped between two hemispheres 1.5 mm in diameter. The pinch force was increased until the tissue was perforated. Results. The perforation force for the pig large bowel was higher than for the small bowel (13.5 +/- 3.7 vs 11.0 +/- 2.5 N; p = 0.014). No difference was found between the human and pig small bowel (10.3 +/- 2.9 vs 11.0 +/- 2.5 N). The intercoefficient of variation varied between 22% and 28%, and the intracoefficient of variation varied between 14% and 18%. Conclusions: The strength of the pig bowel is approximately comparable to the strength of the human bowel, and, therefore, testing of graspers on pig bowel is justified. However, due to the large interindividual variation, large safety margins should be taken into account.