Botulinum toxin is a potent inhibitor of the release of acetylcholine
from nerve endings. It has previously been shown that it can effective
ly reduce lower oesophageal sphincter pressures both in animals and hu
mans with achalasia. This examined the hypothesis that injected botuli
num toxin could also reduce sphincter of Oddi pressure in patients wit
h sphincter of Oddi dysfunction. Two patients with postcholecystectomy
pain syndrome were diagnosed with sphincter of Oddi dysfunction (by b
iliary manometry in one patient and by hepatobiliary scanning criteria
in the other). Botulinum toxin was injected into the sphincter of Odd
i, by a sclerotherapy needle passed through a duodenoscope. In the fir
st patient, intrasphincteric injection of botulinum toxin reduced sphi
ncter pressure by about 50%, an effect that was sustained for at least
four months. In the second patient, intrasphincteric injection caused
about a 50% improvement in bile flow, with normalisation of scintigra
phy. Neither patient showed any sustained improvement in pain despite
these objective findings. Both patients eventually had endoscopic sphi
ncterotomy, which also did not result in symptomatic improvement in ei
ther patient. No side effects were seen. Intrasphincteric botulinum to
xin is a simple and effective means of lowering sphincter of Oddi pres
sure. This technique has potential for being useful clinically.