The SpyGlass™ Digital Catheter is intended to provide direct visualization and guide optical and accessory devices for diagnostic and therapeutic applications during endoscopic procedures in the pancreaticobiliary system. It is specifically designed for the complete visualization of the extrahepatic biliary tree. The SpyGlass™ incorporates a perfusion channel to retain a good field of view and a greater optical resolution than traditional bile duct scopes. Additionally, it has a four-way angle which allows to easily visualize narrow and intricate ducts, such as the cystic and intrahepatic bile ducts [9]. The characteristics of SpyGlass™ Discover allows the percutaneous or laparoscopic transcystic exploration of CBD and the CBDS removal. Furthermore, SpyGlass™-guided electrohydraulic or laser lithotripsy can be used for difficult common bile duct stones not amenable to conventional endoscopic therapy.

Recently, there have been several reports regarding the peroral use of the SpyGlass™ DS for the diagnosis of indeterminate biliary stricture [8] and cystic duct neoplasm [9]. Furthermore, the use of SpyGlass™ technology for single-operator transpapillary [10] or percutaneous [11] cholangioscopy for removing difficult stones has been described too.

To our knowledge, this case series is the second and the largest published in the literature that includes patients undergoing intraoperative laparoscopic transcystic treatment of CBDS using SpyGlass™ Discover during cholecystectomy.

Up to now, only a series of four cases of patients undergoing intraoperative laparoscopic transcystic treatment of CBDS using SpyGlass™ Discover during cholecystectomy was reported by Kouli et al. with good outcomes [12].

Also a case of a patient with a huge stone in the CBD successfully treated with laparoscopic choledochotomy and cholangioscopy using SpyGlass™ Discover was reported by Palermo et al. [13]. However, probably for the huge diameter of the stone, the CBD exploration in this case was not performed with the transcystic technique.

There are many advantages of laparoscopic CBDS removal using SpyGlass™ Discover during cholecystectomy. First of all, the laparoscopic cholangioscopy is likely burdened with low risks due to the fact that it is not necessary to perform papillosphincterotomy. Our series confirms this low-risk profile, in particular, it showed no major complication after the procedure, no acute pancreatitis or post-procedural bleeding. Furthermore, this procedure is readily available, because the operation could be entirely performed by acute care surgeons or general surgeons during laparoscopic cholecystectomy, without needing endoscopic training. In patients with ACC with suspected CBDS, the opportunity to simultaneous treatment of CBDS during ELC, offers the possibility of enormously reducing the time between ACC diagnosis and the execution of ELC with better outcomes for these patients [3,4,5,6].

It should be noted that in our series, the total LOS is quite long, as, until recently, in our institution, the device was available only under special request due to the previous hospital’s administrative policy. Because the device is currently fully functional, we expect the preoperative time to be shorter. Indeed, most patients with ACC and associated CBDS are likely to receive ELC and simultaneous CBDS removal within 72h from admission.

Another advantage of this technique is the possibility to explore the CBD also in patients with altered gastrointestinal anatomy or in case of difficult access to the papilla (e.g., in the case of intradiverticular papilla). In our series, two patients with CBDS underwent successful laparoscopic CBDS removal after a failed ERCP due to the difficulty of papilla intubation.

The present series shows the safety and effectiveness of the intraoperative laparoscopic transcystic treatment of CBDS using SpyGlass™ Discover during cholecystectomy, reporting a success rate of 89% and no major complications.

The present study has evident limitations. First of all, this is a retrospective case series. The sample size is limited, and lacks a control group. However, this series represents one of the first pieces of evidence of the innovative application of SpyGlass™ Discover cholangioscope. Results are encouraging, and it emerges how the procedure is feasible, effective, and safe. The next step will be to compare the efficacy and risk profile of this procedure with ERCP followed by cholecystectomy. In this regard, the "INtraoperative Approach with eventual Clearance of Common bilE duct by SpyGlass™ Discover vs Sequential strategy in patients with acute calculus cholecystitis and Intermediate/high risk of common BiLE duct stone (INACCESSIBLE)" will soon begin in Italy. In this trial, patients with ACC with high/intermediate risk of CBDS, according to the score by Khoury et al. [14, 15], will be randomized to receive ERCP + ELC in two-stage procedures (control group) or simultaneous ELC + SpyGlass™ cholangioscopy and CBDS removal (study group).