Sleeve gastrectomy: a restrictive procedure?

Diet and surgically-induced weight loss have been shown to lead to alterations in motor and sensory function of the stomach. We investigated the clinical outcome and gastric emptying of solid foods in morbidly obese (MO) patients following sleeve gastrectomy (SG).

We studied 23 MO patients [(7 males, 16 females), mean age 38.9 +/- 11.0 years (range 20-64 years), mean weight 135.1 +/- 19.0 kg (range 97-167 kg), mean BMI 47.2 +/- 4.8 kg/m(2) (range 39.6-56.0 kg/m(2))] who each underwent a sleeve gastrectomy (SG) for weight reduction. At the monthly follow-up visits, variations in weight and BMI changes, postoperative meal size and frequency, and presence of gastrointestinal symptoms were recorded. 11 patients underwent scintigraphic measurement of the gastric emptying of a solid meal pre- and 6 months postoperatively.

A significant reduction in patients' weight was evidenced at 6 and 12 months postoperatively [98.6 +/- 11.8 kg and 87.0 +/- 10.7 kg respectively (P=0.001)]. BMI decreased to 35.2 +/- 4.3 kg/m(2) at 6 months and to 31.1 +/- 4.5 kg/m(2) at 12 months, respectively (P=0.001). Although meal size was drastically reduced, meal frequency increased postoperatively in 12 patients (52.2%). Only 5 patients (21.8 %) reported occasional vomiting after meals following SG. The gastric emptying half-time (T1/2) accelerated (47.6 +/- 23.2 vs 94.3 +/- 15.4, P<0.01) and the T-lag phase duration decreased (9.5 +/- 2 min vs 19.2 +/- 2 min, P<0.05) post-operatively. The percentage of the meal emptied from the stomach 90 min after consumption increased significantly after SG (75.4 +/- 14.9% vs 49.2 +/- 8.7%, P<0.01).

This study indicates that following SG, the stomach empties its contents rapidly into the small intestine and symptoms of vomiting after eating (characteristic of restrictive procedures) are either absent or very mild. Therefore, the term 'restrictive' is possibly ill-advised for this new bariatric operation. It remains for other mechanisms of energy intake reduction, such as intestinal distension and satiety signals through gut hormones to be investigated, to comprehensively explain precisely how this 'food limiting' procedure results in weight loss.