An apparatus for providing a restriction and sensing a parameter
associated with an anatomical structure comprises a restriction device
and a sensing device. The restriction device is secured around a portion
of anatomical structure and is operable to form a restriction within
anatomical structure. The restriction may be formed or adjusted in
response to a bolus located within anatomical structure. The restriction
may be formed in response to bolus such that the restriction is formed
before bolus reaches restriction device. Once the bolus passes and no
more boluses are present, the restriction relaxes and loosens anatomical
structure. The restriction device may comprise a gastric band, among
other things, and the sensing device may comprise a strain gauge that is
configured to detect a bolus passing down an esophagus.