Hybrid minimally invasive surgery--a bridge between laparoscopic and translumenal surgery

BACKGROUND

The peroral transluminal approach to the peritoneal cavity appears safe, feasible, and may further reduce the invasiveness of surgery. However, flexible endoscopes have multiple limitations inside the peritoneal cavity, which can potentially be overcome by blending the use of both a laparoscope and a flexible upper endoscope--a hybrid approach. The goal of the present study was to evaluate a hybrid minimally invasive technique for cholecystectomy in a porcine model.

METHODS

Hybrid cholecystectomies were performed in acute experiments on 50-kg pigs under general anesthesia. Pneumoperitoneum was created with a Veress needle, and a laparoscopic 10-mm port was inserted. Under laparoscopic observation, the gastric wall incision was done with an endoscopic needle-knife and sphincterotome, and the upper endoscope was advanced into the peritoneal cavity. A laparoscopic 10-mm port was inserted into the right upper quadrant of the abdomen for gallbladder traction to facilitate exposure of the cystic duct and artery. Via the biopsy channel of the flexible endoscope, and using a knife with an isolated tip, a needle knife, and clips, both the cystic duct and artery were identified, clipped, and transected. The gallbladder itself was then dissected and retracted through the mouth, and the gastric wall incision was closed with endoscopic clips.

RESULTS

Five hybrid cholecystectomies were performed without complications. The laparoscopic port enabled a stable pneumoperitoneum, good traction and counter-traction, and improved spatial orientation and visualization. Necropsy did not reveal any intraperitoneal complications.

CONCLUSIONS

The hybrid approach increases safety of initial gastric puncture and gastric wall incision, improves orientation and navigation of the flexible endoscope inside the peritoneal cavity, simplifies peroral transgastric cholecystectomy, and could be used to decrease invasiveness of laparoscopic surgery and to facilitate development and clinical introduction of transgastric endoscopic procedures.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s00464-007-9329-2) contains supplementary material, which is available to authorized users.

Comparison of intraabdominal pressures using the gastroscope and laparoscope for transgastric surgery

BACKGROUND

The peroral transgastric endoscopic approach for intraabdominal procedures appears to be feasible, although multiple aspects of this approach remain unclear. This study aimed to measure intraperitoneal pressure in a porcine model during the peroral transgastric endoscopic approach, comparing an endoscopic on-demand insufflator/light source with a standard autoregulated laparoscopic insufflator.

METHODS

All experiments were performed with 50-kg female pigs under general anesthesia. A standard upper endoscope was advanced perorally through a gastric wall incision into the peritoneal cavity. The peritoneal cavity was insufflated with operating room air from an endoscopic light source/insufflator. Intraperitoneal pressure was measured by three routes: (1) through the endoscope biopsy channel, (2) through a 5-mm transabdominal laparoscopic port, and (3) through a 16-gauge Veress needle inserted into the peritoneal cavity through the anterior abdominal wall. The source of insufflation alternated between on-demand manual insufflation through the endoscopic light source/insufflator using room air and a standard autoregulated laparoscopic insufflator using carbon dioxide (CO(2)).

RESULTS

Six acute experiments were performed. Intraperitoneal pressure measurements showed good correlation regardless of measurement route and were independent of the type of insufflation gas, whether room air or CO(2). On-demand insufflation with the endoscopic light source/insufflator resulted in a wide variation in pressures (range, 4-32 mmHg; mean, 16.0 +/- 11.7). Intraabdominal pressures using a standard autoregulated laparoscopic insufflator demonstrated minimal fluctuation (range, 8-15 mmHg; mean, 11.0 +/- 2.2 mmHg) around a predetermined value.

CONCLUSION

Use of an on-demand unregulated endoscopic light source/insufflator for translumenal surgery can cause large variation in intraperitoneal pressures and intraabdominal hypertension, leading to the risk of hemodynamic and respiratory compromise. Safety may favor well-controlled intraabdominal pressures achieved with a standard autoregulated laparoscopic insufflator.

Laparoscopic surgery and the parasympathetic nervous system

BACKGROUND

Laparoscopic surgery preserves the immune system and has anti-inflammatory properties. CO2 pneumoperitoneum attenuates lipopolysaccharide (LPS)-induced cytokine production and increases survival. We tested the hypothesis that CO2 pneumoperitoneum mediates its immunomodulatory properties via stimulation of the cholinergic pathway.

METHODS

In the first experiment, rats (n = 68) received atropine 1 mg/kg or saline injection 10 min prior to LPS injection and were randomization into four 30-min treatment subgroups: LPS only control, anesthesia control, CO2 pneumoperitoneum, and helium pneumoperitoneum. In a second experiment, rats (n = 40) received atropine 2 mg/kg or saline 10 min prior to randomization into the same four subgroups described previously. In a third experiment, rats (n = 96) received atropine 2 mg/kg or saline 10 min prior to randomization into eight 30-min treatment subgroups followed by LPS injection: LPS only control; anesthesia control; and CO2 or helium pneumoperitoneum at 4, 8, and 12 mmHg. In a fourth experiment, rats (n = 58) were subjected to bilateral subdiaphragmatic truncal vagotomy or sham operation. Two weeks postoperatively, animals were randomized into four 30-min treatment subgroups followed by LPS injection: LPS only control, anesthesia control, CO2 pneumoperitoneum, and helium pneumoperitoneum. Blood samples were collected from all animals 1.5 h after LPS injection, and cytokine levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Serum tumor necrosis factor-alpha (TNF-alpha) levels were consistently suppressed among the saline-CO2 pneumoperitoneum groups compared to saline-LPS only control groups (p < 0.05 for all four experiments). All chemically vagotomized animals had significantly reduced TNF-alpha levels compared to their saline-treated counterparts (p < 0.05 for all), except among the CO2 pneumoperitoneum-treated animals. Increasing insufflation pressure with helium eliminated differences (p < 0.05) in TNF-alpha production between saline- and atropine-treated groups but had no effect among CO2 pneumoperitoneum-treated animals. Finally, vagotomy (whether chemical or surgical) independently decreased LPS-stimulated TNF-alpha production in all four experiments.

CONCLUSION

CO2 pneumoperitoneum modulates the immune system independent of the vagus nerve and the cholinergic pathway.