Background: The laparoscopic adjustable gastric band (LAGB) has previously been classified as a restrictive procedure; physically limiting meal size. Recently, the key mechanism has been hypothesized to be the induction of satiety without restriction. Effects can be controlled by modifying LAGB volume, possibly as a result of effects on gastric emptying or transit through the LAGB.
Methods: Successful LAGB patients underwent paired, double blinded, esophageal transit and gastric emptying scintigraphic studies; with the LAGB at optimal volume and near empty. A new technique allowed assessment of emptying and transit through the infra- and supraband compartments.
Results: Fourteen of 17 patients completed both scans (six males; mean age, 48.9 ± 11.3 years, % excess weight loss 69.0 ± 15.2). At optimal volume a delay in transit of semi-solids into the infraband compartment was observed in ten patients vs. three when the LAGB was empty, (p = 0.01). The median retention of a meal in the supraband compartment immediately after cessation of intake was: empty 2.8% (2.3-7.9) vs. optimal 3.6% (1.7-4.5), (p = 0.57). Overall gastric emptying half time (minutes) was normal at both volumes: optimal 64.2 ± 29.8 vs. empty 95.2 ± 64.1, (p = 0.14). LAGB volume did not affect satiety before the scan: optimal 4.3 ± 1.9 vs. empty 4.0 ± 2.2, (p = 0.49), or 90 min later: optimal 6.1 ± 1.9 vs. empty 5.9 ± 1.4, (p = 0.68).
Conclusions: The optimally adjusted LAGB briefly delays semi-solid transit into the infraband stomach without physically restricting meal size. The supraband compartment is usually empty of an ingested meal 1-2 min after intake ceases and overall gastric emptying is not affected.