Cyclic Change of Sphincter of Oddi Motility and Its Relationship with Small Bowel Migrating Motor Complex in Humans.

Background: Several animal and human studies have reported that sphincter of Oddi (SO) motility shows cyclical changes during the fasting state. However, to date, the relationship between the SO motility and the migrating motor complex (MMC) of the small bowel (SB) remains unclear in humans.
Aims: We observed SO motility over a long study period and evaluated its relationship with the MMC of the SB in humans using percutaneous long-term manometry.
Methods: Our study included patients with hepatolithiasis who required percutaneous transhepatic catheter placement and subsequently underwent choledochoscopy and stone removal. Long-term percutaneous transhepatic SO manometry was performed after complete stone removal. SO and SB motility were simultaneously recorded.
Results: SO motility showed cyclical phasic changes with periodic high-frequency contractions similar to the MMC contractions of the SB. All high-frequency contractions of the SO coincided with phase III contractions of the MMC of the SB. The proportions of phase III contractions of SO and SB were similar, but the proportions of phase I (P = 0.001) and phase II (P = 0.002) contractions were significantly different. The mean basal SO pressure was observed to significantly increase in phase III compared to phase I (P = 0.001) and phase II (P = 0.001) contractions.
Conclusions: SO motility in humans showed cyclical phasic changes closely coordinated with the MMC of the SB in a fasting state; however, the proportion of phases differed between the SO and the SB. The basal pressure significantly increased during physiological high-frequency phase III contractions of the SO.