Crittenden JP, Dattilo JB. Sphincter of Oddi Dysfunction. 2021 Feb 23. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–.
The patient’s presentation, in combination with the results of their examination, should be used to stratify them to into three classes of sphincter of Oddi dysfunction. Specific diagnostic criteria for SOD include:
Transaminitis (greater 2 times the upper limit of normal on 2 or more occasions)
Common bile duct dilation (greater than 10 mm on US; greater than 12 mm on ERCP)
Utilizing these criteria, patients are classified as follows:
Type I SOD: all three Type II SOD: biliary pain and one of the other two criteria. Type III SOD: biliary pain only 
The results of this classification will impact the subsequent treatment plan.
Results: Among 88 patients who were randomized (mean age, 52 years; 21 (24%) women), 85 (97%) completed the trial. During 18 months of follow-up, patients in the early surgery group had a lower Izbicki pain score than patients in the group randomized to receive the endoscopy-first approach group (37 vs 49; between-group difference, -12 points [95% CI, -22 to -2]; P = .02). Complete or partial pain relief at end of follow-up was achieved in 23 of 40 patients (58%) in the early surgery vs 16 of 41 (39%)in the endoscopy-first approach group (P = .10). The total number of interventions was lower in the early surgery group (median, 1 vs 3; P < .001). Treatment complications (27% vs 25%), mortality (0% vs 0%), hospital admissions, pancreatic function, and quality of life were not significantly different between early surgery and the endoscopy-first approach.
Conclusions and relevance: Among patients with chronic pancreatitis, early surgery compared with an endoscopy-first approach resulted in lower pain scores when integrated over 18 months. However, further research is needed to assess persistence of differences over time and to replicate the study findings.