The effect of laparoscopic adjustable gastric bands on esophageal motility and the gastroesophageal junction: analysis using high-resolution video manometry.

BACKGROUND: Laparoscopic adjustable gastric bands (LAGB) are a safe and effective treatment for obesity. Conflicting data exist concerning their effect on the esophagus, gastroesophageal junction, and mechanism of action. These patients will increasingly require accurate assessment of their esophageal function. METHODS: Twenty LAGB patients underwent high-resolution video manometry with the LAGB empty, 20% under, 20% over, and at their optimal volume. Twenty obese controls were also studied. Effects on esophageal motility, the lower esophageal sphincter (LES), and the gastroesophageal junction were measured. Transit during liquid and semisolid swallows was assessed. RESULTS: The intraluminal pressure at the level of LAGB was a mean of 26.9 (19.8) mm Hg. This pressure varied depending on the volume within the LAGB and was separate to and distal to the lower esophageal sphincter LES. The LES was attenuated compared to controls (10 vs 18 mm Hg; p < 0.01) although relaxed normally. Esophageal motility was well preserved at optimal volume compared to 20% overfilled, with 77% normal swallows vs 51%, p = 0.008. Repetitive esophageal contractions were observed in 40% of swallows at optimal volume compared to 16% in controls, p = 0.024. In comparison to controls, the transit of liquid, 21 vs 8 s (p < 0.001), and semisolids, 50 vs 16 s (p < 0.001), was delayed. CONCLUSIONS: In LAGB patients, the LES is attenuated, although relaxes normally. Esophageal motility is preserved, although disrupted by overfilling the band. In the optimally adjusted LAGB, a delay in transit of liquids and semisolids through the esophagus and band is produced, along with an increase in repeated esophageal contractions.

Measuring frequency of spontaneous swallowing.

A new multi-sensory non-invasive portable system capable of detecting spontaneous swallowing in a patient population has been developed. Swallowing signals are recorded via Electromyogram (voltage potentials generated by throat muscles), an accelerometer (laryngeal elevations) and a microphone (cervical auscultation) affixed to the neck at the coniotomy region. Simultaneous signal comparison of all three modalities provides a vastly more reliable measure of swallowing frequency by rejecting artefacts associated with speech, body movement, coughing and background intereferences. The operational accuracy of the system was validated by a hand-held manual counter on a healthy subject undertaking everyday activities. Preliminary results showed a recorded mean spontaneous swallowing frequency of 1.32 swallows/minute and a slighly higher mean voluntary swallowing frequency of 1.52 swallows/minute with the intake of 100 ml of water. The device was able to detect 94.3% of dry swallows correctly, with each sensor responding differently to various noise interferences. The proposed system has potential to provide additional diagnostic information in clinical research of possible physiological problems associated with an abnormal swallowing frequency across a range of medical fields.