Device for Safely Closing Trocar Sites in Minimally Invasive Abdominal Surgery

Abstract

Laparoscopic and robotic surgeries of the abdomen require a trocar to facilitate entry and removal of instrumentation. Some of these trocars are 5mm or less, but some trocars for these surgeries are larger, with 8mm to 15mm trocars commonly used. One of the well-known problems seen in minimally invasive surgery to the abdomen is the resulting defect left in the abdominal wall following removal of the trocars. Occasionally, especially after removal of larger trocars, a defect is left that is large enough to allow omentum or segments of small intestine to become entrapped within the resulting space in the abdominal wall. These trocar site hernias can cause pain, but they also may lead to small bowel obstruction and bowel ischemia or even infarction, perforation and death. The likelihood of a trocar site hernia is increased when the minimally invasive procedure requires removal of an organ or a mass. This often requires dilatation of the trocar site opening.1,2,3 Re-operation to reduce and repair trocar site hernias adds significant cost to the healthcare system. Two separate studies report that incidence of trocar site hernias are in the ranges of 0.65%–2.8%4 and 1.5%–1.8%5,6. Based on a 2016 report published by the American Society for Metabolic and Bariatric Surgery (ASMBS), 196,0007 bariatric procedures were performed in 2015. Assuming an average incidence rate of 1.7%, and based on the cost analysis provided by a 2008 case study8, in bariatric surgery alone, it is estimated that the treatment and hospitalization of such hernias adds an additional $86.2M to healthcare costs. Several methods and devices exist to prevent the occurrence of trocar site hernias. However, closing superficial fascia externally is difficult, especially in obese patients, and often requires extending the skin incision significantly. Most instruments to close the potential hernia site involve introducing a hollow needle with a built-in, grasping device through tissue on one side of the defect and into the abdominal cavity. This puts internal structures at risk for potential injury. One end of suture is introduced with this needle and then using a separate instrument through a different trocar this suture is held while the needle is removed. The needle device is then re-introduced through tissue on the opposite side of the defect, and the suture is handed back to the needle device and pulled out completing a U-stitch to close the potential hernia site. If a surgeon inserts a finger into the abdomen along the trocar site to guide the needle, there is the potential for injury to the surgeon’s finger. Therefore, we set about to design a device to close trocar site defects that would work efficiently, while being safe from injury to the patient or the surgeon, and preferably without the need for a separate instrument through a different trocar to assist.