Colonic diverticular perforation by a migrated biliary stent

Abstract Rationale: Plastic endobiliary stents, after endoscopic retrograde cholangiopancreatography, can get spontaneously dislocated from the common bile duct and migrate intothe distal bowel. Most migrated biliary stents are removed with the passing of stool. However, migrated biliary stents can cause bowel perforation, albeit rarely, and surgical intervention may be required. Recently, we observed a colonic diverticular perforation caused by a migrated biliary stent, and we have reported this case with a review of the literature. Patients concerns: A 74-year-old man presented with severe right lower quadrant pain after biliary stent insertion 1month ago. Diagnoses: Abdominal computed tomography revealed perforation of the proximal ascending colon by the migrated biliary stent, combined with localized peritonitis. Interventions: Emergency diagnostic laparoscopic examination revealed penetration of the proximal ascending colon by the plastic biliary stent, and right hemicolectomy was performed. Outcomes: On pathological examination, colonic diverticular perforation by the biliary stent was confirmed. The patient was discharged without any additional complications. Lessons: Endoscopic retrograde cholangiopancreatography endoscopists must always be cautious of the possibility of stent migration in patients with biliary stents in situ. In cases of biliary stent dislocation from the common bile duct in asymptomatic patients, follow-up with serial, plain abdominal radiographs, and physical examination is needed until confirmation of spontaneous passage through stool. In symptomatic cases suggesting peritonitis, abdominal computed tomography scan confirmation is needed, and early intervention should be considered.


Introduction
Endoscopic biliary stents have been widely used for internal biliary drainage during endoscopic retrograde cholangiopan-creatography (ERCP). Dislocation and migration of the endobiliary stent from the common bile duct (CBD) occasionally occurs. [1,2] Dislocated biliary stents usually migrate to the distal bowel owing to peristalsis, and spontaneously pass out with feces, not requiring additional intervention so long as it does not cause symptoms. [3] However, distal bowel perforation by migrated biliary stent occurs rarely, and it may require surgical intervention. [3][4][5][6][7] Herein, we report a case of colonic diverticular perforation caused by a migrated biliary stent, which is a very rare, late complication of ERCP, with a comprehensive review of previously reported cases.

Case report
A 74-year-old man presented with abdominal pain. He had a medical history of ERCP and laparoscopic cholecystectomy due to cholangitis with CBD stones and cholecystitis with gallbladder stones about 1 year ago. Biliary colic, associated with fever and chills, was observed. Physical examination revealed the presence of tenderness (and the absence of rebound tenderness) in the right upper quadrant area. Icteric sclera was also observed. Laboratory findings revealed white blood cell counts of 10,730/mm 3 , hemoglobin levels of 15.3 g/dL, total bilirubin levels of 3.0 mg/dL, aspartate aminotransferase levels of 346 IU/L, alanine aminotransferase levels of 85 IU/L, alkaline phosphatase levels of 156 IU/L, and gamma-glutamyl transferase levels of 1010 IU/L. Abdominal computed tomography (CT) revealed multiple CBD stones with bile duct dilation. ERCP was performed to remove the CBD stones, followed by endoscopic retrograde biliary drainage with a 10 Fr x 7 cm straight-type plastic stent inserted into the CBD to control acute suppurative cholangitis (Fig. 1). The patient was discharged without early complications. One month later, he presented with severe right lower quadrant (RLQ) pain. Physical examination revealed tenderness in the RLQ area with rebound tenderness. Laboratory findings revealed white blood cell counts of 8700/mm 3 , hemoglobin levels of 14.5 g/dL, total bilirubin levels of 1.1 mg/dL, aspartate aminotransferase levels of 19 IU/L, alanine aminotransferase levels of 11 IU/L, alkaline phosphatase levels of 53 IU/L, gamma-glutamyl transferase levels of 99 IU/L, and C-reactive protein levels of 12.5 mg/dL. On plain abdominal radiography, the migrated biliary stent was found in the distal bowel (located in the RLQ    (Fig. 2). Abdominal CT revealed perforation of the proximal ascending colon by the migrated biliary stent, combined with localized peritonitis. However, there was no evidence of ascites, pneumoperitoneum, or peritonitis ( Fig. 3). Emergency diagnostic laparoscopic examination revealed penetration of the proximal ascending colon by the plastic biliary stent, and right hemicolectomy was performed. On pathological examination, colonic diverticular perforation by the biliary stent was confirmed (Fig. 4). The patient was discharged without any additional complications. The patient has provided informed consent for publication of the case. The study was approved by the Institutional Review Board of the Inje University Seoul Paik Hospital (IRB No. PAIK 2021-06-012-001).

Discussion
Biliary stent migration can occur in 5% to 10% of patients with endoscopic biliary stenting. [1] The risk factor for biliary stent migration from the CBD to the distal bowel has not yet been established. In a retrospective cohort study, biliary plastic stent migration occurred more frequently in benign biliary strictures than in malignant biliary strictures. [2] Distal migration was associated with long stents, and proximal and postcholecystectomy strictures, whereas proximal migration was associated with short stents, and distal and non-postcholecystectomy strictures. Migrated plastic biliary stents in the large intestine, which have passed through the narrow diameter of the small intestine, rarely cause symptoms. Colon perforations due to migrated plastic biliary stents are very rare. The sigmoid colon was the most commonly involved segment. [5] Bowel perforation by a dislocated endobiliary stent was associated with structural bowel abnormalities or variations, such as postoperative bowel adhesion, diverticulosis, hernia, or stricture. [3] [3] F/85 Diverticulosis CBD stone Straight N/A Sigmoid Sigmoidectomy Anderson 2007 [17] F/80 Diverticulosis CBD stone Straight 5 mo Sigmoid Endoscopic removal Namdar 2007 [7] F/65 N/A Post-cholecystectomy bile leakage Straight 12 Fr x 10 cm 3 mo Rectum Rectal resection Bagul 2010 [18] F/79 Diverticulosis Post-cholecystectomy bile duct stricture Double pigtail 10 Fr x 9 cm 1 mo Sigmoid Endoscopic removal Jafferbhoy 2011 [19] F/82 Diverticulosis Post-cholecystectomy bile leakage Straight 7 Fr x 7 cm 3 mo Sigmoid Endoscopic removal and clip closure Lankisch 2011 [20] F/65 N/A Pancreas head cancer with CBD invasion Straight 10 Fr x 10 cm 2 wks Sigmoid Surgery Malgras 2011 [21] 73 y/o Diverticulosis Pancreas head cancer with CBD invasion Straight 10 Fr x 5 cm 15 d Sigmoid Hartmann procedure Wagemakers 2011 [22] F/76 Diverticulosis CBD stone N/A 1 mo Sigmoid Sigmoidectomy Alcaide 2012 [23] M/73 Diverticulosis CBD stone with benign biliary stricture Straight 10 Fr x 12 cm 15 d Sigmoid Endoscopic removal and clip closure Jones 2013 [24] M/66 N/A Post-op CBD stricture Straight 3 mo Cecum Endoscopic removal Mady 2015 [25] M *

Diverticulosis Pancreas head cancer with CBD invasion N/A 4 wks Sigmoid
Hartmann procedure Virgilio 2015 [5] Case 1, F * The detailed clinical features of the colon perforation cases by distal migrated biliary stents are summarized in Table 1. A total of 30 cases of colon perforation, including the current case, were identified. Most cases were associated with colonic diverticulum (20 out of 30 cases), and the most commonly involved colonic segment was the sigmoid colon (25 sigmoid colon, 1 cecum, 1 ascending colon, 1 splenic flexure, 1 rectum, 1 appendix). A total of 22 cases required surgical treatment, and 8 patients recovered by medical treatment without surgery.
In conclusion, we report a case of perforation of the proximal ascending colon caused by a migrated biliary stent. ERCP endoscopists must always be cautious of the possibility of stent migration in patients with biliary stents in situ. In cases of biliary stent dislocation from the CBD in asymptomatic patients, followup with serial, plain abdominal radiographs and physical examination is needed until confirmation of spontaneous passage through stool. In symptomatic cases suggesting peritonitis, abdominal CT scan confirmation is needed, and early intervention should be considered.