Intrasphincteric injection of botulinum toxin for suspected sphincter of Oddi dysfunction

Botulinum toxin is a potent inhibitor of the release of acetylcholine from nerve endings. It has previously been shown that it can effectively reduce lower oesophageal sphincter pressures both in animals and humans with achalasia. This study examined the hypothesis that locally injected botulinum toxin could also reduce sphincter of Oddi pressure in patients with sphincter of Oddi dysfunction. Two patients with postcholecystectomy pain syndrome were diagnosed with sphincter of Oddi dysfunction (by biliary manometry in one patient and by hepatobiliary scanning criteria in the other). Botulinum toxin was injected into the sphincter of Oddi, by a sclerotherapy needle passed through a duodenoscope. In the first patient, intrasphincteric injection of botulinum toxin reduced sphincter 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 scintigraphy. Neither patient showed any sustained improvement in pain despite these objective findings. Both patients eventually had endoscopic sphincterotomy, which also did not result in symptomatic improvement in either patient. No side effects were seen. Intrasphincteric botulinum toxin is a simple and effective means of lowering sphincter of Oddi pressure. This technique has potential for being useful clinically.