What technical barriers exist for real-time fluoroscopic and video image overlay in robotic surgery?

BACKGROUND: A hypothetical advantage of the da Vinci console is its ability to integrate multiple visual data sources. Current platforms for augmented reality surgery fuse pre-operative radiographic studies but are limited with their ability to update with intra-operative imaging. The aim of our study was to evaluate the feasibility of real-time radiographic image overlay with current technology. METHODS: S-video composite output from a fluoroscopic C-arm was superimposed onto the video output of the da Vinci device. Image superimposition disparity measurements were evaluated in a bench model. The feasibility of robotic dissection assisted by real-time cholangiogram and intravenous pyelogram was evaluated. RESULTS: Image alignment resulted in a radiographic blind spot and image disparity with severely limited application in an in vivo model. CONCLUSIONS: External collisions of the robotic device and visual disparity in multiple planes negate the current implementation of fluoroscopic overlay and will require more elegant methods of computer-assisted registration.

A comparative study of adhesion formation and abdominal wall ingrowth after laparoscopic ventral hernia repair in a porcine model using multiple types of mesh.

BACKGROUND: The ideal mesh for laparoscopic ventral hernia repair is not yet identified. METHODS: We laparoscopically placed polypropylene (PPM), expanded polytetrafluoroethylene (ePTFE), and polyester with antiadhesive collagen layer (PCO) in eight pigs using sutures and tacks for fixation. After 28-day survival, we compared adhesion formation, fibrous ingrowth, and shrinkage among the types of mesh. RESULTS: Mean area of adhesions to PCO (8.25%) was less than that to ePTFE (57.14%, p < 0.001) or PPM (79.38%, p < 0.001). Adhesions peel strength was less for PCO (2.3 N) than for PPM (16.1 N, p < 0.001) or ePTFE (8.8 N, p = 0.02). Peel strength of mesh from the abdominal wall was less for ePTFE (1.3 N/cm of mesh width) than for PCO (2.8 N/cm, p = 0.001) or PPM (2.1 N/cm, p = 0.05). ePTFE area (94.4 cm(2)) was less than that for PCO (118.6 cm(2), p < 0.001) or PPM (140.7 cm(2), p < 0.02). CONCLUSION: PCO had fewer and less severe adhesions than ePTFE or PPM while facilitating excellent ingrowth of the adjacent parietal tissue.

Laparoscopic evaluation of intestinal ischemia using fluorescein and ultraviolet light in a porcine model.

BACKGROUND: The laparoscopic use of fluorescein and ultraviolet light may be a useful diagnostic tool that potentially could reduce the time until diagnosis and the subsequent mortality of mesenteric ischemia. METHODS: Eight pigs were subjected to a pneumoperitoneum pressure of 7 mmHg, and another eight pigs were exposed to a pressure of 14 mmHg. A segment of small bowel was devascularized. Two filters were used to create ultraviolet light. Pigs from each pressure group were given various intravenous fluorescein doses. The ischemic segment of the small intestine and other structures were inspected laparoscopically with the filters attached. A videotape was evaluated by resident and attending surgeons. RESULTS: Ischemic bowel was seen as a darkened silhouette against the viable fluorescent tissue. Overall, the results show that the use of ultraviolet light and fluorescence in the laparoscopic model is adequate for allowing the identification of ischemic bowel. CONCLUSIONS: The laparoscopic use of ultraviolet light combined with intravenous fluorescein dye is an effective diagnostic tool for evaluating mesenteric ischemia in pigs.