Background: Aiming to clarify the mechanism of weight loss after the restrictive bariatric procedure of sleeve gastrectomy (LSG), the volumes and pressures of the stomach, of the removed part, and of the remaining sleeve were measured in 20 morbidly obese patients.
Methods: The technique used consisted of occlusion of the pylorus with a laparoscopic clamp and of the gastroesophageal junction with a special orogastric tube connected to a manometer. Instillation of methylene-blue-colored saline via the tube was continued until the intraluminal pressure increased sharply, or the inflated stomach reached 2,000 cc. After recording of measurements, LSG was performed.
Results: Mean volume of the entire stomach was 1,553 cc (600-2,000 cc) and that of the sleeve 129 cc (90-220 cc), i.e., 10% (4-17%) and that of the removed stomach was 795 cc (400-1,500 cc). The mean basal intragastric pressure of the whole stomach after insufflations of the abdominal cavity with CO(2) to 15 mmHg was 19 mmHg (11-26 mmHg); after occlusion and filling with saline it was 34 mmHg (21-45 mmHg). In the sleeved stomach, mean basal pressure was similar 18 mmHg (6-28 mmHg); when filled with saline, pressure rose to 43 mmHg (32-58 mmHg). The removed stomach had a mean pressure of 26 mmHg (12-47 mmHg). There were no postoperative complications and no mortality.
Conclusions: The notably higher pressure in the sleeve, reflecting its markedly lesser distensibility compared to that of the whole stomach and of the removed fundus, indicates that this may be an important element in the mechanism of weight loss.