Case report of rare cause of small bowel obstruction: distal migration of metal biliary stent requiring enterotomy

INTRODUCTION

Endoscopic biliary stent placement is a mainstay in the management of benign and malignant biliary strictures. Stent migration is a known complication of biliary stents. Whilst distal migration can often be managed expectantly, complications requiring intervention can include bowel obstruction, perforation, and enteric fistulas formation.¹ The most common site of perforation from distal biliary migration is the duodenum, and the most common type of migrated stent is plastic stent.² Whilst management of bowel perforation due to distal migration usually requires surgery, the management of bowel obstruction without perforation is less well explored in the literature, with reported management ranging from non-operative, to endoscopic, to surgical. Furthermore, the introduction of fully-covered metal stents and various novel anchoring devices has made migration less common and there are no case reports to our knowledge of small bowel obstruction caused by a fully covered metal biliary stent.³ Here in we report a case of a high grade mid-small bowel obstruction secondary to distal migration of fully covered metal biliary stent, without evidence of bowel perforation. This was managed successfully with laparotomy, enterotomy and primary closure.

CASE REPORT

A 69-year-old male presented November 2023 to the Sunshine Coast University Hospital, Australia with two weeks of lethargy, abdominal pain and obstructive jaundice. He had a history of a benign distal common bile duct stricture secondary to chronic alcohol-induced pancreatitis. This has been managed with a 10 mm×6 cm self-expanding covered metal biliary stent inserted in June 2021. His other background included gastro-esophageal reflux disease and a previous laparoscopic cholecystectomy. His blood tests revealed an elevated white cell count to 13.4×10^9/L (normal range 4.5-011×10^9/L) and a total and conjugated bilirubin of 210 µmol/L (normal range <20.5 µmol/L) and 160 µmol/L (normal range<5.1 µmol/L) respectively. A computed tomography (CT) scan demonstrated a partially inferiorly migrated biliary stent with the tip in contact with segment D3 of the duodenum with resultant stent obstruction. The patient was admitted under the local gastroenterology service, commenced on broad-spectrum intravenous antibiotics, and planned for inpatient endoscopic retrograde cholangiopancreatography (ERCP). On his third day of admission, the patient developed worsening abdominal pain and vomiting. Examination findings included a distended, generally tender abdomen without signs of guarding. Abdominal Xray was performed which showed dilated small bowel loops and a foreign body with the appearance of a biliary stent in the left pelvis (Figure 1). A subsequent CT scan confirmed biliary stent migration to the mid-jejunum causing small bowel obstruction, without evidence of perforation (Figure 2). The patient was managed with an emergency lower midline laparotomy. Intra-operative findings included an intra-loop small bowel adhesion in the mid-jejunum, resulting in a 180 degrees bend (Figure 3). The migrated biliary stent was impacted in the proximal segment of this bend causing complete luminal obstruction (Figure 4). There was no perforation identified. A 1 cm enterotomy was performed, and the stent was successfully retrieved (Figure 5). The enterotomy was then closed transversely with interrupted 3-0 polydioxanone suture. The patient had an uncomplicated recovery post-operatively. Repeat ERCP was complicated by inability to cannulate the common bile duct thus a percutaneous transhepatic cholangiogram (PTC) and placement of internal/external biliary drain was performed. He has had two subsequent biliary dilatations via PTC and replacement of his stent. On outpatient review his serum bilirubin has normalized and he is continuing to recover well.

DISCUSSION

Stent migration is a known complication of biliary stents. Rates of stent migration vary depending on the type of stent, indication and anchoring technique, but migration rate sits between 5 and 10%.^2-5 A more recent multicenter study specifically looking at fully covered self-expanding metal stents such as that used in this case cite a migration rate of 10.7%.⁵ Distal migration can usually be managed expectantly as uncomplicated passage per rectum is the norm.⁶ However, complications of distal stent migration include bowel obstruction, perforation, and there are even rare case reports of colonic fistulas because of prolonged implantation into the small bowel wall.¹ The most common site of obstruction and perforation from distal biliary migration is the duodenum, and the most common type of migrated stent is plastic stent.²

It is thought that this patient’s interloop adhesion-presumably secondary to his previous laparoscopic cholecystectomy-prevented uncomplicated distal passage. Indeed, the stent was found intraoperatively to be impacted at the level of this adhesion. As such, we suggest that expectant management of distal stent migration is less reliable in patients with significant previous abdominal surgical history, or history of known intra-abdominal adhesions. Whilst metal stents address the common issue of occlusion encountered with plastic stents, the rate of stent migration with metal stents appears in several studies to be increased, particularly covered metal stents.³ Interestingly, there are very few case reports of metal biliary stent migration causing small bowel obstruction.⁷ This may either be due to metal stents having a reduced tendency to block the intestinal lumen, or because of their more recent introduction into the standards of care of biliary obstruction.

A potential mechanism for migration of this patients’ metal stent was stent blockage leading to the patient’s presentation with pain and obstructive jaundice. Subsequent stent migration may have occurred because of pressure build up in the biliary system proximal to the stent. Management of distal biliary stent migration complicated by small bowel obstruction or perforation is a point of contention. Recommendations range from endoscopic retrieval, laparoscopy, and open surgical repair.^2,7-11

Management decisions depend on the location of the offending biliary stent and whether peritonitis is present. There are no robust prospective trials given the rarity of the condition. There are a few case reports detailing management with endoscopic retrieval, however in these cases the stents were either located in more endoscopically-accessible areas of the bowel or operative management was contraindicated due to patient factors.^9,10 We suggest that obstruction at the level of the jejunum due to a biliary stent necessitates surgical management given endoscopic management is not possible.

CONCLUSION

In conclusion, we present the rare case of a migrated metal biliary stent becoming impacted in the mid small bowel with resultant small bowel obstruction. The case was managed with emergency laparotomy and enterotomy. We suggest that caution be taken in pursuing expectant management of distal stent migration in patients likely to have significant intra-abdominal adhesions, due to an elevated risk of complication. Biliary stent migration complicated by obstruction should be managed endoscopically if early and feasible and surgically if endoscopic management fails or intestinal perforation occurs.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

1. 1. Blake AM, Monga N, Dunn EM. Biliary stent causing colovaginal fistula: case report. Jsls. 2004;8(1):73-5.
2. 2. Zorbas KA, Ashmeade S, Lois W, Farkas DT. Small bowel perforation from a migrated biliary stent: A case report and review of literature. World J Gastrointest Endosc. 2021;13(10):543-54.
3. 3. Lam R, Muniraj T. Fully covered metal biliary stents: A review of the literature. World J Gastroenterol. 2021;27(38):6357-73.
4. 4. Nam HS, Kang DH. Current Status of Biliary Metal Stents. Clin Endosc. 2016;49(2):124-30.
5. 5. Haseeb A, Siddiqui A, Taylor LJ, Mills A, Kowalski TE, Loren DE, et al. Use of fully covered self-expanding metal stents for benign biliary etiologies: a large multi-center experience. Minerva Gastroenterol Dietol. 2018;64(2):111-6.
6. 6. Morosin T, De Robles MS, Still A. Duodenal diverticulum at the site of the major papilla may be a risk factor for biliary stent migration. J Surg Case Rep. 2021;(3).
7. 7. Ikeda T, Nagata S, Ohgaki K. Intestinal obstruction because of a migrated metallic biliary stent. Gastrointest Endosc. 2004;60(6):988-9.
8. 8. Marmo R, Rea M, Pecora A, Sansone S, Rotondano G. Small bowel obstruction due to penetrating migrated biliary stent: removal with a clip applicator via double balloon enteroscopy. Dig Liver Dis. 2013;45(9):783-5.
9. 9. Rasalkar DD, Paunipagar BK, Sonavane B. Migrating biliary stent with destination at the ileocecal junction causing intestinal obstruction and obstructive biliopathy. Indian J Radiol Imaging. 2010;20(4):304-6.
10. 10. Garg K, Zagzag J, Khaykis I, Liang H. Surgical relief of small bowel obstruction by migrated biliary stent: extraction without enterotomy. JSLS. 2011;15(2):232-5.
11. 11. Saravanan MN, Mathai V, Kapoor D, Singh B. Fractured metallic biliary stent causing obstruction and jejunal perforation. Asian J Endosc Surg. 2013;6(3):234-6.