Comparison of minimally invasive methods of parietal cell vagotomy in a porcine model

Parietal cell vagotomy (PCV) is an accepted therapy for peptic ulcer disease. Traditional operative PCV results may be obtained laparoscopically or endoscopically. The purpose of this study was to quantitatively evaluate newer methods of PCV.

Variations in PCV, gastroscopic chemoneurolysis and laparoscopic photoneurolysis, were evaluated in 20 to 25 kg pigs. Traditional operative PCV was performed by laparotomy and served as the operative control. With a posterior truncal vagotomy, a PCV was performed laparoscopically by an anterior seromyotomy with either operative division of the neurovascular bundles with titanium clips or with a defocused CO2 laser. Transesophageal gastroscopic PCV was performed by transmucosal injections of the chemoneurolytic agents, 0.75% cobaltous chloride or 0.1% benzalkonium chloride. Adequacy of PCV at the time of operation was assessed by endoscopic Congo red testing. Two weeks later, repeat Congo red testing was performed by open gastrotomy. Quantitation of completeness of PCV and statistical comparison was determined by photographing the pentagastrin-stimulated gastric mucosa 5 minutes after Congo red application and subsequent comparison of innervated area versus total gastric mucosal area by a computer-driven digitized area-calculation program.

All PCV techniques studied produced significant acid-secretory reduction, and both laparoscopic and gastroscopic PCV denervated the parietal cells in a manner comparable with operative PCV. Laser photoneurolysis could only be accomplished by producing full-thickness necrosis of the gastric wall. Submucosal injection of cobaltous chloride produced granulomatous nodules with foreign body crystals. Unlike operative and laparoscopic PCV, transmucosal gastroscopic benzalkonium PCV did not produce gross gastroparesis.

All evaluated laparoscopic and endoscopic PCV techniques effectively denervated the parietal cells of the porcine stomach when evaluated at 2 weeks after treatment. Gastroscopic submucosal injection of benzalkonium chloride produced effective denervation with no evident histologic tissue changes and suggestive evidence of normal gastric emptying. Further evaluation with more extended periods of observation of these new techniques of performing PCV appear warranted.