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.

An endoscopically implantable device stimulates the lower esophageal sphincter on demand by remote control: a study using a canine model

BACKGROUND AND STUDY AIMS

Implantable microstimulators (IMS) have been used in a variety of medical conditions. Selective stimulation to increase lower esophageal sphincter (LES) pressure may be useful in the control of gastroesophageal reflux disease. We evaluated on-demand stimulation of the LES with an endoscopically implanted microstimulator.

MATERIALS AND METHODS

We performed acute experiments in three 30-kg dogs. After LES manometry, a 3.3 mm x 28 mm microstimulator (the Bion) was implanted into the LES. Manometry was repeated with and without IMS stimulation to record the changes in LES pressure. Stimulation amplitude was varied from 3 mA to 10 mA, with a fixed frequency of 20 Hz and a pulse width of 200 microsec.

RESULTS

The mean LES pressures prior to IMS implantation in the three dogs were 13.0 mm Hg, 5.0 mm Hg, and 14.9 mm Hg. The mean pressures were not significantly changed by IMS placement. There were no documented changes in LES pressure when the amplitude of stimulation was less than 8 mA. After stimulation of the IMS at a setting of 10 mA in dogs 1 and 2 and at 8mA in dog 3, however, the resultant LES pressures were 62.1 mm Hg, 35.1 mm Hg, and 26.8 mm Hg respectively, more than three times higher than post-implantation baseline levels (P < 0.02).

CONCLUSIONS

The LES pressure can be increased using an on-demand microstimulator. The implantation procedure is minimally invasive, represents a novel therapeutic approach to gastroesophageal reflux disease, and may have therapeutic potential for other gastrointestinal motility disorders.

Transgastric endoscopic splenectomy: is it possible?

BACKGROUND

We have previously reported the feasibility of diagnostic and therapeutic peritoneoscopy including liver biopsy, gastrojejunostomy, and tubal ligation by an oral transgastric approach. We present results of per-oral transgastric splenectomy in a porcine model. The goal of this study was to determine the technical feasibility of per-oral transgastric splenectomy using a flexible endoscope.

METHODS

We performed acute experiments on 50-kg pigs. All animals were fed liquids for 3 days prior to procedure. The procedures were performed under general anesthesia with endotracheal intubation. The flexible endoscope was passed per orally into the stomach and puncture of the gastric wall was performed with a needle knife. The puncture was extended to create a 1.5-cm incision using a pull-type sphincterotome, and a double-channel endoscope was advanced into the peritoneal cavity. The peritoneal cavity was insufflated with air through the endoscope. The spleen was visualized. The splenic vessels were ligated with endoscopic loops and clips, and then mesentery was dissected using electrocautery.

RESULTS

Endoscopic splenectomy was performed on six pigs. There were no complications during gastric incision and entrance into the peritoneal cavity. Visualization of the spleen and other intraperitoneal organs was very good. Ligation of the splenic vessels and mobilization of the spleen were achieved using commercially available devices and endoscopic accessories.

CONCLUSIONS

Transgastric endoscopic splenectomy in a porcine model appears technically feasible. Additional long-term survival experiments are planned.