Surgical interventions for CP include pancreatic duct drainage procedures, such as Puestow and Partington procedures [19, 20], and resection procedures, such as PD, DP, and duodenum-preserving pancreatic head resection (Beger procedure) [21]. Pancreatic duct drainage preserves the pancreatic function, but is less effective in cases requiring control of inflammation in the pancreatic head or tail, particularly when an inflammatory mass is present [22]. Conversely, pancreatectomy effectively removes localized lesions but carries a high risk of pancreatic exocrine and endocrine insufficiency [23]. Notably, these procedures, with the exception of PD, are not indicated for CBD strictures, which may require alternative interventions. Historically, biliary reconstruction has often been performed simultaneously with other procedures such as the Frey procedure [4, 13, 14]. However, recent reports have demonstrated that CBD strictures can improve with the Frey procedure alone [4, 18]. Our findings support the potential effectiveness of this method.

CBD strictures are a well-recognized complication of CP, second only to the pseudocyst formation. They are most frequently associated with an inflammatory mass or calcification in the pancreatic head, occurring in up to 50% of patients with an inflammatory head mass [24, 25]. The reported incidence of CBD strictures in CP varies widely (2.7%–45.6%) [4], and among those requiring surgical intervention, the rate increases to 15–60% [26]. At our institution, the incidence rate was 10.7% (16 of 149 cases), potentially reflecting the increasing use of endoscopic treatment as a first-line approach.

CBD strictures in CP can result from edema, pseudocyst formation, or encasement of the CBD by fibrotic processes [4]. Although strictures due to edema or pseudocysts often resolve spontaneously, surgical intervention is traditionally recommended to prevent cholangitis and secondary biliary cirrhosis [4, 14, 18]. However, low incidence of these complications and advances in endoscopic techniques have shifted the management strategies [1, 4, 14]. Surgical options including CJ, choledochoduodenostomy, and bile duct reinsertion during the Frey procedure are still used in selected cases [14, 27]. However, these techniques carry long-term risks including cholangitis and anastomotic strictures. In our study, some patients experienced improvement in CBD strictures without requiring biliary reconstruction. This finding suggests that coring out of the pancreatic head during the Frey procedure may have a direct beneficial effect on CBD strictures. Additionally, the reduction of inflammation in the pancreatic head may resolve the associated edema and cysts, further contributing to the alleviation of CBD strictures.

A review of previous studies on the historical evolution of surgical interventions for CBD strictures in CP indicates that before the development of endoscopic intervention, surgical treatment typically involves simultaneous biliary reconstruction [6, 16]. Since 2010, four reports have documented surgical interventions for CBD strictures. Ray et al. reported surgical intervention in 41 CP cases with CBD strictures, including 25 cases treated with the Frey procedure alone and 16 cases involving biliary reconstruction including PD. Among the 25 patients treated with the Frey procedure alone, postoperative CBD strictures were observed in two cases: one was managed endoscopically, whereas the other required reoperation with CJ [4]. Rebibo et al. reported 15 cases in which the Frey procedure was performed, all of which involved simultaneous biliary reconstruction [14]. Similarly, Merdrignac et al. described a study of 29 cases treated with procedures involving biliary reconstruction [13]. In another report by Ray et al., surgical intervention was performed in 59 patients: 16 with the Frey procedure alone, 36 with the Frey procedure and simultaneous biliary reconstruction, and 7 with other forms of biliary reconstruction. Notably, CBD strictures improved in 15 of the 16 patients treated with the Frey procedure alone [18]. The data of the cases treated with the Frey procedure alone that were reported across these studies originated from a single institution [4, 18], with potential case overlap. However, when combined with cases from our institution, a total of 47 cases were identified, with postoperative CBD strictures requiring intervention in 4 cases (8.5%) and reoperation in 1 case (2.1%). While these findings suggest that CBD strictures often improve with the Frey procedure alone, no previous study has directly compared the Frey procedure alone with biliary reconstruction.

In this study, we conducted the first comparison between Frey procedure alone and biliary reconstruction, and demonstrated that the Frey procedure alone is sufficient for managing CBD strictures in CP. However, owing to small sample size, it remains unclear which patients truly do not require biliary reconstruction, making it difficult to draw definitive conclusions. Although this uncertainty may be a concern, the availability of endoscopic treatment for persistent postoperative CBD strictures helps mitigate its impact. Furthermore, as demonstrated in our study, in some cases, it was eventually possible to remove the CBD stents after surgery, even after a prolonged period, suggesting that initially forgoing biliary reconstruction may be a reasonable option. Additionally, because pancreatic surgery itself is a major surgery [28, 29], the significantly shorter operative time of the Frey procedure alone helps us to minimize invasiveness. In other words, the Frey procedure alone may be a viable surgical approach for patients with CP with CBD strictures when endoscopic intervention can be safely performed.

The present study was associated with several limitations. First, as a single-center, retrospective observational study, it is inherently subject to potential confounding factors and selection bias. Second, despite our institution being a leading center for CP treatment in Japan, the small sample size limited the generalizability of our findings. To validate these results, a prospective, multi-institutional study is warranted. Despite these limitations, this study revealed that the Frey procedure was effective in many cases of CBD strictures, supporting the findings of previous reports.

In conclusion, based on our single-center experience, while the Frey procedure was effective in resolving CBD strictures in a subset of patients with CP, the need for biliary reconstruction cannot be entirely eliminated, and further studies are warranted to identify the factors predicting successful outcomes with the Frey procedure alone. CP treatment should leverage the strengths of both endoscopic and surgical approaches, emphasizing a complementary and integrative strategy.