Symptomatic and neuropathic changes after endoscopic sphincterotomy (EST) in patients with sphincter of Oddi dysfuntion (SOD) and ERCP contrast filling pain (CFP)

Introduction: Recently, we proved a significant difference in the sensory current perception threshold (SCPT) ratio between the referred pain cutan area (RPA) and the contralateral area in patients with SOD. In a subgroup of patients with SOD, biliary pain could develop upon ERCP manipulation (tender papilla), or during intraductal contrast injection with ERCP (CFP). The aim of the present study was to prospectively analyse the symptomatic and neuropathic changes before and after EST in this subgroup of SOD patients having CFP.

Methods: CFP evoked during ERCP in 7 patients out of 33 consecutive patients with postcholecystectomy pain and SOD (21%). The remaining 26 patients without CFP served as controls. All patients were investigated by our validated questionnaire with visual analogue pain scale (VAS) and quantitative sensory testing (Neurometer® CPT) before and every 3 months after EST during the follow up. The overall follow up was 18 months, ranged from 9 to 24 months.

Results: Based on the ratio of SCPTs we demonstrated a marked hypersensitivity in the RPAs in both SOD patient groups (with or without CFP), but without significant differences between each of them before EST, 2.18±1.07 vs. 2,34±1.14at 2000Hz; 2.22±0.76 vs. 2,34±0.75at 250Hz; and 2.26±0.91 vs. 2.16±0.67at 5Hz, respectively. Furtheremore, no significant differences observed in the improvement of VAS and SCPT ratio between the two groups 3 months after EST. More interestingly, persistent clinical improvement (no pain recurrances after 6 months and during the late follow-up) documented by questionnaire in 28 of 33 (85%) cholecystectomized SOD patients without CFP, versus only 2 out of 7 (28%) in the subgroup of SOD patients having CFP at initial ERCP.

Conclusion: The manifestation of CFP in SOD patients was not associated with a significantly higher level of initial neuroptahic changes or with loss of initial responsiveness to EST, but during the long-term follow-up it was a significant risk factor of symptomatic recurrance.