title: Can endoscopic papillary balloon dilation really preserve sphincter of Oddi function?
abstract: BACKGROUND
  Endoscopic papillary balloon dilation (EPBD) is assumed to preserve sphincter of Oddi function because it causes little trauma to the papilla. However, few studies have addressed this issue specifically. In this study, we investigated whether EPBD can preserve sphincter function, and evaluated whether or not such preservation has clinical significance.
  
  
  METHODS
  Seventy patients with common bile duct (CBD) stones were randomly assigned to EPBD or endoscopic sphincterotomy (EST). Sphincter of Oddi (SO) function was measured by endoscopic manometry before, one week after, and one year after treatment. Incidence of pneumobilia and later complications were compared between the two groups at one year. Series manometric data were compared within each group and between the two groups. For a more detailed analysis of the cumulative incidence of later complications, retrospective cohorts were added to the study groups, giving a total number of 235 patients in the EPBD group and 126 in the EST group.
  
  
  RESULTS
  Baseline characteristics did not differ significantly between the 35 EPBD and 35 EST patients. CBD stones were discharged successfully in all cases. CBD pressure, SO basal and peak pressures, and contraction frequency decreased significantly at one week in both groups. The damage was more severe in the EST group, and SO contraction completely disappeared in 23 patients in this group. The incidence of pneumobilia was significantly lower in the EPBD group than in the EST group (p<0.01) whereas CBD stones recurred and cholecystitis appeared at a similar rate in both groups at one year. A complete series of manometric data up to one year was obtained in 55 patients; 28 in the post-EPBD and 27 in post-EST groups. In the post-EPBD group, SO basal and peak pressures significantly recovered at one year compared with data at one week but these measures still remained significantly lower than those before EPBD (p< 0.01). In the post-EST group, SO contraction did not recover even after one year. A Kaplan-Meier analysis of 235 EPBD and 126 EST patients for a median follow up of 37 months revealed significantly lower incidences of biliary complications such as recurrent CBD stones and cholangitis, and cholecystitis in the EPBD group than in the EST group (p<0.05). The risk of pneumobilia was also significantly lower in the EPBD group (p<0.01).
  
  
  CONCLUSIONS
  Preservation of papillary function after EPBD was not complete but remained somewhat reduced. However, preservation was more successful with EPBD than with EST. Such preservation may be clinically beneficial for the prevention of later complications.
authors.affiliation: First Department of Internal Medicine, Gifu University School of Medicine, Gifu, Japan. yasudaic@cc.gifu-u.ac.jp
authors.forename: I
authors.initials: I
authors.lastname: Yasuda
authors.forename: E
authors.initials: E
authors.lastname: Tomita
authors.forename: M
authors.initials: M
authors.lastname: Enya
authors.forename: T
authors.initials: T
authors.lastname: Kato
authors.forename: H
authors.initials: H
authors.lastname: Moriwaki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002404:Catheterization / Q000009:adverse effects*; D005260:Female; D042882:Gallstones / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D012189:Retrospective Studies; D009803:Sphincter of Oddi / Q000503:physiopathology*; D016717:Sphincterotomy, Endoscopic / Q000009:adverse effects; D018709:Statistics, Nonparametric; D016019:Survival Analysis