Effect of types of resection and manipulation on trocar site contamination after laparoscopic colectomy: An experimental study in rats with intraluminal radiotracer application

Abstract

Background The etiology and incidence of port-site metastases after laparoscopic surgery for colorectal cancer remain unknown. The purpose of this experimental study was to detect and quantify the amount of contamination at the port-site by means of a method utilizing radiolabelled colloid particles following extra-or intracorporeal laporoscopic resection of cecum. Methods Prior to experimental surgery, we obtained a high concentration of luminal colonic radiotracer activity by per anum application of sulphur colloid molecules labelled with Tc-99m pertechnetate. In three main groups of rats, we either resected a portion of cecum extracorporeally or intracorporeally, or did no resection. Each main group was further divided into two subgroups, in which the manipulations were either autraumatic or traumatic. We excised trocar sites as 2 cm doughnuts after completion of the surgical procedure. We used gamma camera imaging to quantify the amount of radioactive contamination at trocar sites. The background corrected trocar site activity for each rat was calculated. Activities exceeding the maximum background activity were accepted as trocar site contamination. Results We detected an overall incidence of contamination in 44% of rats. This rate were 71% and 17% in traumatic and atraumatic subgroups. The resection itself increased the rate and intensity of contamination, as well (p = 0.04). The most intensive contamination was detected in the intracorporeal resection with traumatic manipulation subgroup (p = 0.0007).Conclusions Both the presence of resection and manipulative trauma seemed to be increasing the rate and intensity of the radioactive activity at the trocar site. When traumatic manipulatiun was exercised, the contamination was so intense that the type of resection did not differ. We concluded that our scintigraphic method would be useful in the intraoperative detection of port site contamination by the tumor cells, and that surgeons would take some preventive measures to prevent future port-site metastases.

Development of a standardized laparoscopic caecum resection model to simulate laparoscopic appendectomy in rats

“…Only in the study by Polat et al . was it identified that an entire laparoscopic caecum resection was performed using two endoloops [23]. Additionally, most studies do not list all operation parameters in detail (such as the way stumps are disinfected, the kinds of trocar or incision that were used and to what extent they enlarged the incision to exteriorize the resectate) (Table 2).…”

“…While most investigators used barbiturate [19,20,22] or ketamine [16-18,21,23] for narcosis, we used isoflurane (Forene®, Abbott GmbH & Co KG, Wiesbaden, Germany), which was also used by Schmelzer et al . [24].…”

“…Regarding the capnoperitoneum, several investigators used an angiocatheter (18 or 25 gauge) in a trocarless method to insufflate the peritoneal cavity [16,17,21,23], while others used proper trocars [18-20,22,24]. As the usage of trocars appears to imitate LA more realistically in comparison with modern human laparoscopy, we consequently used trocars within the present study.…”

“…Three studies used 2-mm forceps and scissors [16,17,23] and another group 3.5-mm forceps and scissors [20], while two other groups performed their operations with 2-mm forceps [21,24]. To extract the specimen, some investigators needed a 4-mm incision [16,17,23] while others required a widening of 1 cm [24]. We compared several instrument sizes and found that 2-mm and 3-mm laparoscopic instruments and trocars were the ideal size for high-precision interventions while keeping the operative trauma at the lowest possible level.…”

“…Polat et al . performed actual laparoscopic caecum resections in rats using two endoloops and intracorporeal dissection [23]. Unfortunately, the authors did not describe their operative procedure in sufficient detail for straightforward reproducibility.…”