These results suggest that movement of cells throughout the peritoneal cavity during laparoscopy is via contaminated instruments, but local cell movement by dispersion possibly within water vapor from the port may also occur.

These findings suggest that cellular contamination of the peritoneal cavity is frequent during laparoscopic cholecystectomy. This may occur when the gallbladder wall is macroscopically breached or when operative choledochography is performed, or by microperforation due to the application of crushing laparoscopic graspers to the gallbladder wall. Glandular cells adhere to instruments in 40% of the operative procedures and may be the main source of dissemination of malignant cells through the peritoneal cavity.

Tumor cells move throughout the peritoneal cavity both at rest and during CO2 insufflation. The pattern of tumor cell dispersion differs with CO2 insufflation. The presence of blood and extended contact of trocars with peritoneal contents are a major factor in trocar and trocar site tumor cell contamination.

Background: Intra-operative hypothermia and port-site recurrence have been associated with laparoscopic surgery. Heating and humidification of insufflating CO, may protect against laparoscopy-associated hypothermia. However, the effect of heated, humidified CO, upon tumour cell movement is unknown. Methods: Twenty-four in vitro studies that used 4-L plastic bottles were performed. Thirteen million human colorectal cancer cells were placed in each bottle. Twelve studies used dry room temperature CO, for insufflation; the remaining 12 used heated, humidified COz as the insufflating gas. Both groups were subdivided into bottles with leaks around the trocars and with airtight sealing around the trocars. Two trocars and a laparoscopic grasper were used. The exiting insufflating gas was filtered and examined for the presence of cells. Laparoscopic instruments agitated the contents of the bottles. The instruments and trocars were washed. These washings were examined for the presence of cells. Results: Heated, humidified CO, insufflation was able to maintain a warmer and more humid environment within the bottles when compared with dry room-temperature CO,. No cells were detected on the gas filters. Tumour cells were found on 12 out of 12 instruments and 1 I out of 12 trocars with dry CO, insufflation. Tumour cells were found on 8 out of 12 instruments and 7 out of 12 trocars with heated humidified CO, insufflation. The only statistically significant difference in tumour cell spread to trocars was found between heating and humidification when no leak was present, and heating and humidification with leak present, and dry insufflation with no leak present ( P = 0.015, Fisher's two-tailed exact test). Conclusions: Heating and humidifying CO, during in vitro laparoscopy does not increase the aerosolization of tumour cells when compared with dry CO,. However, the use of heated and humidified gas with airtight seals around the trocars in vitro may lessen cell deposition on trocars.

Microperforation of the gallbladder by laparoscopic instruments occurs during laparoscopic cholecystectomy.