Feasibility of therapeutic pneumoperitoneum in a large animal model using a microvaporisator

Background: Multimodal therapy is used increasingly in advanced gastrointes tinal tumors. Potential benefits of using an intraoperative adjuvant therap y during laparoscopy for cancer have been documented in animal studies. The aim of this study was to develop a device that could deliver such an intra operative drug therapy. Methods: We developed a micropump suitable for minimally invasive surgery p rocedures that allowed microdroplets of therapeutic substance to be distrib uted into the pneumoperitoneum (CO2), creating a "therapeutic pneumoperiton eum," A closed-loop control system regulates drug delivery according to the gas flow. In vitro, the micropump is able to aerosolize various aqueous an d ethanol solutions, including cytostatic and bacteriostatic drugs and adhe sion-modulating agents. The size of the microdroplets has been optimized to prevent visual artifacts. Results: The micropump was tested in an animal model (pig). The system was inserted into a 5-mm trocar. After insufflation of a 12-mm CO2 pneumoperito neum, laparoscopic sigmoid colon resections could be performed with no spec ial difficulties. No fog developed, and no system-related complication was observed. At autopsy, the active principle was distributed to all exposed p eritoneal surfaces. Conclusions: As opposed to conventional peritoneal washing, therapeutic pne umoperitoneum reaches the entire peritoneal surface, allowing an optimal dr ug distribution. Drug diffusion into the tissues is enhanced by the intrape ritoneal pressure. Precise determination of the instantaneous and total dru g quantity is possible. Therefore, this drug delivery system has several ad vantages over conventional irrigation. its potential domains of application are locoregional cancer therapy, prevention of port-site recurrences, immu nomodulation, analgesia, peritonitis, and prevention of postoperative adhes ions.