Introduction Sphincter of Oddi Dysfunction is characterised by pancreaticobiliary-type pain and is difficult to diagnose without direct manometry which carries a significant risk of pancreatitis. The injection of Botulinum toxin (Botox) into the biliary element of the Sphincter of Oddi (SO) may offer temporary pain relief and predict those patients who would benefit from endoscopic sphincterotomy.
Methods 24 patients underwent injection of 25 units (1 ml) of Botox into each of four quadrants close to the ampulla at Endoscopic Retrograde Cholangiopancreatography (ERCP). Patients evaluated their symptoms by completing an 11-point Likert Pain Scale before Botox injection and again at 2 and 12 weeks. Patients experiencing a transient improvement of ≥2 points were offered endoscopic sphincterotomy (ES).
Results There were 20 post-cholecystectomy patients (six type 2; fourteen type 3) and four gallbladder intact (all type 3) by modified Hogan-Geenan criteria. Eight (33%) patients did not respond to Botox of whom two underwent ES and one responded. The remaining six continue with medically unexplained pain. Four had a complete and two partial response (25%) that was sustained (>6 months) and required no further intervention. 10 (42%) had a transient response to Botox with worsening of pain ≥2 points at 12 weeks. Of these six (60%) chose ES and achieved a sustained pain-free response; two (20%) chose repeat Botox injection with sustained response; one declined further intervention; and one was lost to follow. There were no serious adverse events after Botox injection.
Conclusion Botox injection into the SO led to a positive outcome with or without sphincterotomy in 58% of patients. A transient response to Botox accurately predicted response after ES in keeping with earlier reports. Its clinical utility should be compared to manometry in type 3 SOD.