LAUSR

Difficult bile duct cannulation, a commonly encountered and exasperating situation for endoscopists, is often due to obstruction of the bile duct (BD) by an ampullary septum, separating the ducts, which results in repeated entry of the guidewire into the pancreatic duct (PD). Since the risk of post-ERCP pancreatitis (PEP) increases exponentially with repeat guidewire passages into PD [1], this occurrence may be prevented with the use of pancreatic guidewire-assisted methods, including single guidewire methods, the doubleguidewire (DGW) technique, and transpancreatic sphincterotomy (TPS) (Fig. 1), all of which may help facilitate BD cannulation in such situations. The limited literature that exists comparing these advanced cannulation techniques mostly includes underpowered studies. The authors Pecsi et al. [2], from Hungary, have previously performed a metaanalysis comparing the success and complication rates of TPS and needle-knife precut papillotomy (NKPP) in patients with difficult biliary access, suggesting the former to have higher success with cannulation and lower bleeding, PEP rates. Goff [3] first described 5–7 mm TPS with an overall success rate of up to 97.5%, although subsequent studies described varied success and complication rates, likely reflecting differences in the technique. The key, however, for successful immediate biliary access with TPS appears to be creation of a large TPS during the first attempt. This complete unroofing of the papilla facilitates biliary cannulation with no significant increase in reported perforation rates. Although the incidence of post-TPS bleeding ranges from 3 to 5% [4], much higher rates (close to 15%) were reported from centers with a smaller case volume. Severe post-TPS bleeding, though rare, appears to be through incision of an aberrant retroduodenal artery but was unrelated to the length of TPS. PEP incidence in the setting of TPS ranges from 5 to 21% in the absence of PD stent prophylaxis but can be reduced to 3.5% with PD stenting [3]. In this issue of Digestive Diseases and Sciences, the authors Pécsi et al. [5] report the results from an expanded meta-analysis now comparing TPS to needle-knife precut papillotomy (NKPP), needle-knife fistulotomy (NKF), and DGW techniques. A total of 14 studies were incorporated into the meta-analysis that were of heterogeneous design including randomized controlled trials (RCTs) and prospective, retrospective cohort studies. Comparison of the cannulation success rates, TPS had higher success when compared to DGW (OR 2.72; 95% CI 1.30–5.69) and NKPP (OR 2.32; 95% CI 1.37), but was not significantly different when compared to NKF (OR 1.38; 95% CI 0.32–5.96). TPS had high overall cannulation success rate of 89.7%, which remained consistent even in the subgroup analysis including only RCTs, at 91.7%. Surprisingly, although there were no significant differences in the PEP rates between TPS and DGW or NKPP, the PEP rate was higher with TPS when compared to NKF (11.5% vs 2.1%, respectively). Moreover, the post-procedural bleeding and perforation rates were not significantly different between the techniques compared. The authors are to be commended on this exhaustive systematic review with meta-analyses for each of the outcomes of interest as well as the multiple subgroup-based sensitivity analyses. Furthermore, the authors discussed the potential benefits of TPS due to superior control with the depth of cutting compared with the freehand precut techniques and also the ability to place a prophylactic PD stent after sphincterotomy. The results, however, need to be interpreted with caution due to the inherent statistical and design limitations inherent in the literature available for this systematic review and also due to the observation that the choice of suitable technique used to overcome difficult biliary cannulation often varies by anatomy, experience of the endoscopist, * Anthony N. Kalloo [email protected]