Concomitant CBD stones are encountered in up to 18% of patients undergoing acute cholecystectomy for gall stone complications [10]. With advancements in laparoscopic techniques and acute care surgery capabilities, the management in these instances has evolved from open CBD exploration to laparoscopic techniques of CBD clearance and cholecystectomy. The one-stage laparoscopic approach, which entails a transcystic or a transductal intervention in the management of choledocholethiasis, has been advocated by several authors. However, there is a declining trend in CBD exploration since this approach is both  technically demanding and time-consumingwhich  tips the balance in favor of endoscopic CBD clearance using ERCP [5, 11]. ERCP with cholangiography and papillotomy has been available in most referral centers for more than three decades [12]. The overall success rate of ERCP in terms of CBD clearance by an experienced endoscopist is over 95% [5, 13]. ERCP is applied as part of a one-stage (laparoscopic cholecystectomy + IO-ERCP) or as a two-stage procedure (pre- or post-operative ERCP and LC). There are several advantages with a one-stage compared to a two-stage approach. Selecting patients with CBD stone(s) for ERCP can be challenging even with the use of different predictive models based on clinical, laboratory and imaging findings [14, 15]. This makes the one-stage approach more appealing when intra-operative cholangiography is available. A total of 24 (12%) patients in the currents study had CBD stones detected by intraoperative cholangiography that had not been identified preoperatively.

There are several ERCP procedure-related complications including pancreatitis (1–30%), pancreatic necrosis (0.3–0.6%) and mortality (0.4%), that can be avoided with over the guidewire (the Rendezvous technique) IO-ERCP. This allows avoidance of the critical phase of retrograde inadvertent cannulation of the pancreatic duct [15]. A meta-analysis done by Arrezo and colleagues including a total of 430 patients from four randomized controlled trials observed a lower incidence of overall complications for the one-stage Rendezvous technique (11.2%) compared to the two-stage approach (18.1%) [OR 0.56; 95% confidence interval (CI) 0.32–0.99; p = 0.04] [7]. The one-stage approach was also associated with fewer cases of clinical pancreatitis (2.4%) than the two-stage technique (8.4%) (OR 0.33; 95% CI 0.12–0.91; p = 0.03) [7]. In the current study, the rate of procedure-related complications was as low as 4% (n = 8) with 6 (3%) of patients experiencing post-interventional mild pancreatitis and 2 (1%) patients suffered a Strasberg type A bile leak. None of the patients required any additional invasive intervention and were discharged and fully recovered at follow-up. When comparing the two different approaches to CBD clearance in the current study, there was no statistical difference in procedural complications (Table 2).

Another disadvantage of the two-stage procedure is the timing of LC after ERCP. Recommendations vary from 72 h to a 6-week interval post-ERCP for LC, with a recurrent risk of CBD stones of 10% [16, 17]. Likewise, several investigators have noted a higher rate of conversion from LC to open surgery in patients subjected to a preoperative ERCP [18, 19]. One explanation offered by the authors of this finding is inflammation and scarring of the hepatoduodenal ligament through bacterial colonization due to the disruption of the sphincter of Oddi, making dissection of Calot’s triangle more challenging [19]. The mean operation time for LC + IO-ERCP at the two centers in this study was 105 (± 44) min, which should be considered a reasonable time for the combined procedure without any cases requiring conversion to open surgery. In comparison between the study sites, OUH had significantly longer procedure times at 91 (± 41) vs.120 (± 43) min. (p < 0.001), due to the use of the “rendezvous” approach and the  routine practice of intraoperative transcystic cholangiography.

Furthermore, other advantages with the one-stage approach include a single hospital admission and shorter hospital length of stay with a decrease in the total cost of care [17]. The cost of care for patients admitted to Orebro University Hospital in Sweden in the current study are outlined in Table 3. The median (LQ, UQ) postoperative length of stay was 2 (1,  3) days in the current study. The total hospital length of stay was 4 (3,  7) days. The total length of stay in the current study was influenced by factors such as patients with gallstone pancreatitis requiring observation until the laboratory values normalized before being cleared for surgery or older patients needing additional days in hospital to recover from surgery. Another advantage with the one-step procedure is patient satisfaction, which should be investigated further in future studies. Finally, the risk of patient drop-out due to compliance with two different hospital admissions is eliminated with the one-stage approach [20].

Many surgical centers do experience organizational and logistical obstacles with performing LC + IO-ERCP [8, 9]. This is mainly due to the fact that the procedure often requires collaboration between the surgical and gastroenterology/endoscopy teams. However, most of these patients are admitted to emergency surgery units in Europe rather than medical wards. With the evolving Trauma and Emergency Surgery subspecialty in Europe and Acute Care Surgery model in the United States, it may be appropriate to explore the possibility of endoscopy fellowships for surgeons, allowing the surgical teams to carry out both steps of the procedure. The current study does demonstrate low complication rates and did only include IO-ERCP cases carried out by surgeons. An alternative to this would be to have an ERCP-trained endoscopist on the emergency surgical service.