Factors determining optimal gastric band adjustment

Gastric banding is nowadays an effective surgical treatment for obesity. The
band reduces the amount of food which can enter the stomach during a certain
period and helps the patient in this way to reduce weight. The gastric band can
be adjusted at an access port placed just underneath the skin. If the patients*
weight increases, the band is inflated and in case of dysphagia or vomiting,
the band is deflated. The decision to adjust is made on clinical grounds, based
on the doctor*s experience. Hence, there is a large variation in the filling
moments in different patients. In this study will be focused on the effect of
band adjustment with different volumes on esophageal bolus transit time and
clearance, by using high resolution manometry. Simultaneously the pressure in
the gastric band is measured. Physiologically more exact adjustment can help to
achieve good weight loss and to prevent esophageal problems in the long term.

The primary objective of this study is to assess the effect of band placement
and of different stages of band adjustment on the esophageal bolus transit time
and clearance by using intra-esophageal high resolution manometry and impedance
monitoring.

Secondary objectives of this study are:
- to identify the relation between intraband pressure and bolus transit time /
esophageal clearance
- to investigate the predictive value of bolus transit measurement and
intraband pressure measurement for the optimal restriction of the band,
determined by means of a *passage comfort* visual analogue scale.

In this pilot-study, patients come to the UMC Utrecht before the gastric band
placement to assess their esophageal motility pattern preoperatively with high
resolution manometry. Six week postoperatively they return to the UMC for the
first adjustment of their band. During this assessment intraband pressure will
be measured at different filling volumes. At the same time high resolution
manometry is carried out to assess the passage of fluid and food. With this
device, esophageal impedance can also be monitored. These techniques give very
detailed information about the bolus transit time and esophageal clearance.

Before the gastric band placement, high resolution manometry is carried out in
the UMC. In the normal situation the band is adjusted in the Nederlandse
Obesitas Kliniek in Hilversum postoperatively. Participation in the study
implies that the patient comes to the UMC Utrecht for band adjustment, as a
part of this study. The band is inflated / adjusted via a small access port
placed just under the skin. In Hilversum patients have to pay for this
treatment. The gastric band of the participants in this study will be adjusted
during this assessment for free.