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Page 4 of 9 Aabakken et al. Mini-invasive Surg 2021;5:25 https://dx.doi.org/10.20517/2574-1225.2021.09

and the lesser axial support of thinner wires may be a disadvantage in subsequent maneuvers. Again, choice
mostly comes down to personal preference and experience. A special variant for cannulation support, the
[8]
“loop-tip” guidewire, was introduced to support passage through the crevices of the papilla , but it has
since been discontinued.

DIFFICULT CANNULATION
The majority of cannulation attempts are straightforward in expert hands, even in native papillae. However,
difficulties occur for both expected and unforeseen reasons. Difficult cannulations add to the risk of
[9]
complications , and much effort has been channelled into this area since predicting difficult cannulations
might allow pre-emptive measures to minimise adverse outcomes.

A variety of definitions have been suggested for what should be considered difficult. Since it is not always
based on identifiable pre-procedural factors, recent definitions are instead based on features of the actual
cannulation attempt. A study from Scandinavia looked at 907 ERCPs in native papillae in a multicenter
study . Allocating PEP as the determining factor, difficult cannulation was identified as > 5 min duration
[10]
of attempt to cannulate, > 5 passes at the papilla, or > 2 guidewire passages into the pancreatic duct (PD).
These three factors alone, or in combination, were associated with a significant increase in the incidence of
PEP.

One important utility of such a definition is to aid the decision to change the initial strategy of standard
guidewire cannulation. Further persistence with the same technique may finally succeed, but it is likely to
increase the complication risk, so changing the strategy earlier should be considered.

There are number of alternative methods to achieve cannulation success that may be used instead of, or
along with, the initial approach. Common to these techniques are that they require additional skills, add
risk, but increase the chance of eventual cannulation success.

Double-wire technique
Not infrequently, attempts to access the bile duct result in inadvertent guidewire placement in the PD. If
this recurs or results after substantial struggle, leaving it there and proceeding with cannulation alongside
with another wire preloaded in the catheter, the “double wire technique” (DWT) is a viable option. In
theory, the pancreatic wire stabilizes a mobile papilla, straightens the intraduodenal segment of the ducts,
and potentially causes partial blockage of the PD, all components that may increase the chance of
subsequent access to the bile duct. The method was introduced more than 20 years ago and has repeatedly
[11]
been shown to improve cannulation success. The technique has been modified to include placement of a
small-calibre transpapillary pancreatic stent over the guidewire already in the PD, resulting in significant
[13]
protection from PEP , and is currently recommended in recent ESGE guideline on ERCP adverse events
[12]
whenever the DWT is used. Alternatively, a stent can be placed initially in the PD for subsequent alongside-
cannulation or needle knife cutting on the stent.

DWT has been associated with increased risk of PEP. In a recent systematic review comprising 7 RCTs with
difficult cannulation in 577 patients, the authors found a 2-fold increase in risk of PEP using the DWT,
[14]
without increased cannulation success . However, like all problem-solving methods, it may falsely be
blamed for the risk imposed by previous failed cannulation attempts. Also, most studies in that review were
done prior to the standard use of rectal non-steroidal, anti-inflammatory drugs (NSAIDs) for PEP
prophylaxis. The protective role of a pancreatic stent in combination with NSAIDs is not clear .
[13]