Minor Papilla Cannulation and Sphincterotomy

Pancreas divisum (literally “divided pancreas”) is a congenital anatomic variant in which the dorsal and ventral pancreatic ducts completely or partially fail to fuse, and drain separately into the medial wall of the duodenum. Thus in most patients with pancreas divisum the vast majority of the pancreatic ductal system drains via the dorsal duct through the minor papilla. This is the most common pancreatic anomaly, occurring in approximately 10% of the general population, though rates vary worldwide from 2.7% to 22%. The frequency also varies greatly in different endoscopic retrograde cholangiopancreatography (ERCP) series; a systematic review of endoscopic detection of pancreas divisum found a pooled rate of 2.9%, ranging from 1.5% in Asia to 5.8% in the United States and 6.0% in Europe.

About 15% of pancreas divisum cases are of the incomplete type, in which a small branch of the ventral duct communicates with the dorsal duct. The clinical implications of incomplete and complete pancreas divisum are the same.

Although most patients with pancreas divisum do not suffer pancreatic symptoms throughout their lifetime, about 5% have recurrent mild to severe pancreatic pain, acute pancreatitis (often recurrent), or chronic obstructive pancreatitis. These symptoms or diseases are believed to occur because the minor papilla orifice is so small that intrapancreatic dorsal duct pressure is excessively high during active secretion, resulting in inadequate duct drainage and distension. Persistent or recurrent high intraluminal dorsal duct pressure can cause recurrent bouts of acute pancreatitis, and with time the gland undergoes chronic obstructive changes. Therefore pancreas divisum can be considered a predisposing factor for recurrent and chronic pancreatitis.

Dorsal duct obstruction depends on relative stenosis of the minor papilla rather than the presence of pancreas divisum per se. Lowering the transpapillary pressure gradient across the minor papilla, mainly by ERCP and minor papilla endoscopic sphincterotomy (MiES), appears to be essential when this condition is symptomatic.

Patients with acute recurrent pancreatitis seem to have a significantly better response to MiES than those patients with “pancreatic pain” only and those with chronic pancreatitis. However, because some patients with acute recurrent pancreatitis continue to have attacks after effective dorsal ductal drainage, other nonductal abnormalities such as genetic mutations, alcohol use, and autoimmune pancreatitis may play a pathogenic role. As many as 10% to 20% of patients with pancreas divisum and pancreatitis carry at least one allele of the cystic fibrosis gene product or a higher frequency of SPINK1 gene mutation than healthy controls, suggesting a multifactorial origin of pancreatitis in these cases.

Endoscopic identification, cannulation, and MiES are still challenging, and the decision to perform ERCP in patients with pancreas divisum should not be made lightly in view of the greater potential for adverse events. Although minor papilla cannulation can provide the diagnosis of pancreas divisum, noninvasive imaging techniques such as secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP), endoscopic ultrasonography (EUS), or thin-slice coronal computed tomography are preferable (see Chapter 34 ). S-MRCP is the preferred technique, with reported sensitivity, specificity, positive predictive value, and negative predictive value of 73.3%, 96.8%, 82.4%, and 94.8%, respectively. Some radiologists believe that secretin administration during MRCP is essential for diagnosing pancreas divisum, because without hormone stimulation MRCP is nondiagnostic in a substantial proportion of patients. Miss rates of pancreas divisum by MRCP may also be attributable to suboptimal techniques and radiologist inexperience.

This chapter focuses on endoscopic identification and cannulation of minor papilla and on techniques for sphincterotomy and dorsal duct drainage.

Sedation, Supplemental Drugs, and ERCP Accessories

Sedation

Endoscopic cannulation and sphincterotomy of the minor papilla is generally a lengthy procedure, requiring appropriate sedation and analgesia. Deep sedation with propofol is therefore preferred, though moderate sedation can be achieved with repeated doses of benzodiazepines (midazolam) and opioids (meperidine, fentanyl) (see Chapter 6 ).

Antispasmodic Drugs

Antispasmodic agents enhance visualization of the minor papilla and should be readily available for administration. However, these agents should not be administered until the endoscope is passed to the descending duodenum, as gastric distension may occur and make passage through the pylorus difficult. Once the endoscope has been placed in a stable position in front of the minor papilla, in some cases an additional intravenous injection of a smooth muscle inhibitor such as glucagon is required, in 0.25-mg to 0.50-mg increments.

Supplemental Agents

When recognition of the papilla or its orifice is problematic, dyeing techniques or secretin injection can be helpful.

ERCP Accessories

In general, cannulation and papillotomy of the minor papilla can be performed using accessories that are the same as those used for the major papilla (see Chapter 14 ): a sphincterotome or an ERCP catheter and a soft-tip guidewire ( Fig. 21.1, A, B ). If the papillary orifice is very small, a needle-tip catheter (ERCP-1-CRAMER; Cook Medical, Winston-Salem, NC) can be useful. Sometimes a stenotic orifice requires dilation in order to pass standard accessories, which can be done with a tapered 3-Fr to 7-Fr dilator (Soehendra Biliary Dilatation Catheter or Geenen Graduated Dilation Catheter [Cook Medical]; progressive dilation catheter [G-Flex, Nivelles, Belgium]) or a 4-mm balloon-tipped catheter (Titan biliary balloon dilator [Cook Medical]; Eliminator PET biliary balloon dilator [ConMed, Utica, NY]; Hurricane biliary balloon dilator [Boston Scientific, Marlborough, MA]).

The following equipment should be kept in the endoscopy room when attempting minor papilla cannulation and papillotomy:

• Catheters : tapered-tip 3-Fr to 5-Fr catheters, some with metal tips (Glo-tip-1-ST or ERCP-1 metal tip or ERCP-1-Huibregtse-Katon, ERCP-1-CRAMER [Cook Medical]; Contour ERCP [Boston Scientific]; PR-V223Q [Olympus])

• Guidewires : partially or completely hydrophilic 0.018-inch guidewires (Roadrunner [Cook Medical]; Pathfinder [Boston Scientific]); 0.035-inch guidewires with straight and angled tips (Radifocus [Terumo, Elkton, MD]; METRO or Deltawire or Acrobat [Cook Medical]; Dreamwire or Hydra Jagwire or Jagwire [Boston Scientific])

• Sphincterotomes : pull-type short-tip sphincterotome 4-Fr to 5-Fr diameter with a 20-mm to 25-mm cutting wire (Minitome [Cook Medical]) or standard sphincterotome 5.5-Fr to 6-Fr diameter

• Dilators : tapered 4-Fr to 7-Fr dilation catheter or 4-mm balloon dilators (as described above)

• Needle knife : 4-mm cutting wire with or without a channel for passing a guidewire or for contrast injection (Huibregtse [Cook Medical]; MicroKnife [Boston Scientific])

• Pancreatic stents : (a) “prophylactic”: 3-Fr to 5-Fr stents, 2 to 5 cm long, flanged or unflanged with or without a duodenal pigtail; (b) “therapeutic”: 7 to 10 Fr, 3 to 7 cm long, flanged (Zimmon or Geenen [Cook Medical]; Advanix [Boston Scientific])

• Nasopancreatic drainage : 5-Fr diameter (NPDS-5 [Cook Medical]; NPDC-5 [Surgimedic])

• Cautery unit : we use an ERBE generator model ICC 200 (ERBE Elektromedizin, Tubingen, Germany) usually set at effect 3, 120 W, and “ENDOCUT” mode.

Recognition of the Minor Papilla

The first step of the procedure is to locate the minor papilla. It is usually in the right upper quadrant of the visual field when facing the major papilla, 2 to 3 cm cephalic and anterior to the major papilla, but it may be as close as 1 cm from the major papilla, at the rim of its longitudinal fold ( Fig. 21.2 ). The minor papilla can be very small and difficult to locate or quite prominent and, rarely, located within a diverticulum ( Fig. 21.3, A–C ). High-definition white-light endoscopy and advanced electronic imaging techniques may facilitate the identification of the papilla and its orifice ( Fig. 21.4, A ).

Gentle probing of the duodenal folds may be necessary to identify the minor papilla mound and to make it more prominent, although care must be taken to avoid excessive manipulation-related edema that may make it more difficult to identify the papilla.

The endoscopic appearance of the minor papilla can predict pancreas divisum and underlying pancreatographic findings. Bulging of the minor papilla mound and patency of its orifice may differ in patients with normal and abnormal ductography. About 70% of patients with pancreatic dorsal duct abnormalities have substantial bulging and a visible orifice, whereas most cases with a normal pancreatogram have no bulging and/or no visible orifice.

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