Meandering Main Pancreatic Duct as a Relevant Factor to the Onset of Idiopathic Recurrent Acute Pancreatitis

Abstract

BackgroundMeandering main pancreatic duct (MMPD), which comprises loop type and reverse-Z type main pancreatic duct (MPD), has long been discussed its relation to pancreatitis. However, no previous study has investigated its clinical significance. We aimed to determine the non-biased prevalence and the effect of MMPD on idiopathic pancreatitis using non-invasive magnetic resonance (MR) technique.Methods and FindingsA cross-sectional study performed in a tertiary referral center. The study enrolled 504 subjects from the community and 30 patients with idiopathic pancreatitis (7 acute, 13 chronic, and 10 recurrent acute). All subjects underwent MR scanning and medical examination. MMPD was diagnosed when the MPD in the head of pancreas formed two or more extrema in the horizontal direction on coronal images of MR cholangiopancreatography, making a loop or a reverse-Z shaped hairpin curves and not accompanied by other pancreatic ductal anomaly. Statistical comparison was made among groups on the rate of MMPD including loop and reverse-Z subtypes, MR findings, and clinical features. The rate of MMPD was significantly higher for all idiopathic pancreatitis/idiopathic recurrent acute pancreatitis (RAP) (20%/40%; P<0.001/0.0001; odds ratio (OR), 11.1/29.0) than in the community (2.2%) but was not higher for acute/chronic pancreatitis (14%/8%; P = 0.154/0.266). Multiple logistic regression analysis revealed MMPD to be a significant factor that induces pancreatitis/RAP (P<0.0001/0.0001; OR, 4.01/26.2). Loop/reverse-Z subtypes were found more frequently in idiopathic RAP subgroup (20%/20%; P = 0.009/0.007; OR, 20.2/24.2) than in the community (1.2%/1.0%). The other clinical and radiographic features were shown not associated with the onset of pancreatitis.ConclusionsMMPD is a common anatomical variant and might be a relevant factor to the onset of idiopathic RAP.

Anatomic variations of the pancreatic duct and their relevance with the Cambridge classification system: MRCP findings of 1158 consecutive patients

“…Gonoi et al . 16 evaluated that 2.2% (11/504) of subjects had loop and reverse-Z type pancreatic course in Japanese. In our study group, descending course was found in about 62.5%, sigmoid course 30% and vertical course 5.5%, loop course 2%, so the prevalence of vertical and sigmoid course were marked different from their value.…”

“…Gonoi et al . 16 evaluated that the prevalence of pancreas divisum was 2.6 (13/504) in Japanese. We found a prevalence rate of pancreas divisum 4.6%.…”

“…1, 9, 16 The ductal changes of main pancreatic duct are demonstrated on MRCP, however subtle side branch changes can be missed. 1 One of the major limitation of MRCP is the lack of functional information and inability to image the ductal system in distended condition.…”

Santorinicele without pancreas divisum pathophysiology: initial clinical and radiographic investigations

“…Subjects having the following findings were excluded: (1) spindle, cudgel, stick, or branch types of the terminal portion of the dorsal pancreatic duct, in which the calibre changes smoothly (Figure 1) [8-10]; (2) neoplasm in the dorsal portion of the head of pancreas; (3) suspected intraductal papillary mucinous neoplasm in the dorsal pancreatic duct; and (4) other major malformation such as abnormal arrangement of pancreaticobiliary ducts or choledochocele. Minor ventral ductal anatomical variation that does not seem to change the flow of pancreatic juice in the dorsal pancreatic duct, such as meandering main pancreatic duct (loop type or reverse-Z type) [17] may exist. Santorinicele with pancreas divisum (SWPD) was diagnosed for a santorinicele accompanied by pancreas divisum (classical type, pancreas divisum with absent ventral duct, incomplete type) [16] using the same exclusion criteria.…”

Ansa pancreatica as a predisposing factor for recurrent acute pancreatitis

“…Furthermore, serious damage of pancreatic tissue leads to dysfunction of the endocrine and exocrine systems, particularly in the chronic phases of the disease. There are several known causes of pancreatitis, including excessive alcohol consumption, biliary stones, trauma, autoimmunity, metabolic disorders, drugs, iatrogenic, infection, genetic mutations, malignancy, and heredity factors[1-3]; and morphological aberrations such as atypical arrangement of the pancreaticobiliary ductal system[4,5], pancreas divisum[5-8], or a meandering main pancreatic duct[9]. However, recurrent episodes of acute pancreatitis is idiopathic in as many as 20% of patients[8,10,11].…”