The mystery of the ureteric stent in the lumen of the terminal ileum

Abstract

A 65-year-old comorbid female patient presented to our urology department with a history of multiple interventions to treat severe overactive bladder symptoms. She had a history of clam ileocystoplasty, which was then converted to an ileal conduit due to failure to resolve her symptoms. She subsequently developed multiple complications, most significantly ureteroileal stenosis, managed with bilateral ureteric stents. She later decided on bilateral nephrostomies and subsequent antegrade stent insertion. At follow-up, the proximal end of the left stent remained within the kidney and the distal end was free within the abdominal cavity. There was further migration of the stent in its entirety into the lumen of the terminal ileum on subsequent imaging. She denied any significant gastrointestinal symptoms, signs or peritonitis. Consideration was made for the endoscopic removal of the stent by the gastrointestinal team; however, the patient refused any further procedures preferring to be monitored.

BACKGROUND

The insertion of ureteric stents is a common urological procedure. Ureteric stents are placed in order to maintain the patency of the ureter, therefore, the adequate position of the stent is essential in achieving that function. Stents are usually placed under radiological guidance that plays a pivotal role in the monitoring of patients with indwelling stents as well as the evaluation and potential management of patients with stent-related complications.

Unfortunately, this does not totally obliterate the risk of stent migration.

We present a case of a patient who despite the initial correct placement of her stent, the stent was later found to have migrated into the lumen of her ileum. This is a rare occurrence; this is the first such case to be recorded in the literature. Early detection and a high index of suspicion are vital in preventing significant sequelae with migrated stents.

Despite the potential bowel complications arising from the migrated stent, this patient had only occasional mild abdominal pain allowing her to opt for conservative management of the migrated stent.

CASE PRESENTATION

A 65-year-old female patient was transferred to our urology department with an extensive urological history including a clam ileocystoplasty due to significant overactive bladder symptoms. She had multiple comorbidities including chronic obstructive pulmonary disease, hypertension, ischaemic heart disease, epilepsy, chronic kidney disease and continued to be a heavy smoker. She also had a history of a total abdominal hysterectomy and radiotherapy for endometrial cancer. The clam ileocystoplasty was subsequently converted to an ileal conduit at the same time as a simple cystectomy due to the lack of improvement of her symptoms.

Unfortunately, 2 years post cystectomy, she developed severe ureteroileal strictures for which she was managed with long-term retrograde JJ stents. No attempts were made to endoscopically dilate or openly excised the strictured area.

Due to the worsening of her strictures, retrograde ureteric stent exchanges became increasingly difficult that caused her to have bilateral nephrostomies and subsequent antegrade JJ stent insertion and exchange. All stent exchanges were reported as being uneventful with no intraoperative or perioperative complications noted.

During one of her routine stents exchanges, the distal end of the left stent was not found in the conduit despite adequate placement during the previous exchange. On further investigation, it was noted to be within the abdominal cavity (figures 1 and 2). The patient started complaining of left-sided abdominal pain but had no clinical features of peritonism.

Figure 1.

Scout image from the initial CT 6 months post left stent insertion. The right stent (without the radio-opaque markers) terminates in the ileal conduit, whereas the lower end of the left stent lies posteriorly in the presacral space.

Figure 2.

3D reconstruction image from the initial CT 6 months post left stent insertion. The lower end of the left stent lies in the presacral space.

A left-sided nephrostomy was planned in order to antegradely remove the stent however she did not want any further surgical procedures despite experiencing one episode of left-sided pyelonephritis, which subsequently resolved with conservative management. Subsequent CT of the kidneys, ureters and bladder showed continuous migration of the stent that eventually lodged in the terminal ileum (figures 3 and 4). She remained free of any gastrointestinal or urological symptoms.

Figure 3.

3D reconstruction image from the subsequent CT 16 months post insertion. Please note the migration of the left ureteric stent into the small bowel loops within the pelvis.

Figure 4.

3D reconstruction image from the CT 23 months post insertion. The migrated left ureteric stent remains in the pelvis within the small bowel loops.

Outcome and follow-up OUTCOME AND FOLLOW-UP

The patient was referred to the gastrointestinal surgeons for consideration of endoscopic removal of the stent, however, after consultation with them, she declined any further interventions as she had become asymptomatic.

DISCUSSION

Ureteric stents are a useful tool in the urology arsenal and have both therapeutic and prophylactic applications. The cystoscopic insertion of a ureteric stent is a minimally invasive procedure with low morbidity and high success rates,¹ but is not exempt from complications. When ureteric stents are used for periods of up to 3 months, complications are infrequent, but longer indwelling times are associated with increased risks of incrustation, infections, secondary stone formation, obstruction of the stented tract and migration.² Bladder overactivity symptoms caused by the lower end of the stent can occur in up to 80%–90% of patients leading to urgency, frequency, haematuria and dysuria.³ Loin pain due to bypassing the antireflux mechanism at the trigone of the bladder can also occur. In general, studies have shown there to be a general decrease in the quality of life of patients who have ureteric stents in situ.⁴

Although retrograde cystoscopic insertion of a ureteric stent is a one-stage procedure, it however requires the use of general anaesthetic or sedation as well as an operating theatre. On some occasions, a retrograde stent insertion may not be possible due to difficult anatomy, patient’s morbidity and so on, and an antegrade approach will have to be undertaken necessitating a percutaneous nephrostomy and antegrade stenting. This may be performed either in a one-stage or a two-stage procedure depending on the experience and practice of the interventional radiologist performing the procedure.

There is little in the literature about extraureteric stent migration, although cases have been reported with stent migration into the renal pelvis, inferior vena cava, inferior vena cava and extending into the right atrium.^{2 5} This is the first reported case of enteral migration of the stent.

In a study performed by Slaton and Kropp, it was concluded that a shorter than the ideal stent, distal curl of <180 degrees and proximal curl in the upper calyx rather than the renal pelvis seem to be significant factors predisposing to migration.⁶ Stent migration occurrence has decreased significantly since the introduction of the J or pigtail ends that anchors the stent reducing the risk of displacement over time. In addition, polyurethane is recognised to have better shape memory (and thus to more effectively conform to the urinary tract) compared with silicone, reducing the likelihood of ureteral stent migration along the urinary tract. In contrast, stents made of softer materials have been found to be more prone to migration.^7–10 Percuflex stents, which was the type used in this case, are designed with high retention coil strength to help maintain pigtail shape and prevent stent migration.¹¹

It is believed that extraureteric stent migration is a result of a very fragile ureteric wall that could be due to chronic inflammation, ureteric wall trauma and even malignancy.² The exact aetiology of benign ureteroenteric anastomotic strictures is unclear but they are most likely the result of periureteral fibrosis and scarring secondary to ischaemia or urine leakage at the anastomotic site.¹² The exact mechanism for the stent migration is not known, however it potentially can be attributed to trauma during her increasingly difficult stent exchanges to an already ischaemic strictured area. This could lead to the migration of the distal end of the stent through the traumatic segment. Having had previous pelvic radiotherapy, there is a risk of late injury to the bowel due to small vessel injury with possible subsequent inflammation fibrosis, ischaemia and oedema.¹³ With the continuous mechanical irritation of the weakened segment of continuous bowel loop by the free distal end of the stent, this trauma can favour the penetration of the stent into the lumen of the bowel aided by the peristaltic movement of both the ureter and the small bowel. Latency periods of >30 years for radiation-induced bowel changes have been reported.¹⁴

Foreign bodies (FB) can be trapped in the small intestine and those patients are very often asymptomatic, although they may present with a range of symptoms based on the location, physical characteristics and the content of the object and complications like perforation and bleeding.¹⁵ Between 80% and 90% of FBs are passed spontaneously, whereas 10%–20% require an endoscopic procedure, and 1% require open or laparoscopic surgery.¹⁶ Conservative management is the treatment of choice for blunt, short (<6 cm) and narrow (<2 cm in diameter) FBs with no complications.¹⁵ Preventative removal is indicated in sharply pointed FBs which are likely to cause erosion, ulceration and/or perforation of the bowel wall potentially leading to extraluminal or extra-abdominal migration, and in large or sharp FBs that have remained stagnant at the ileocecal valve increasing the risks of obstruction, ileus, volvulus and perforation.^{17 18}

The majority of FB patients essentially need observation and monitoring, with serial plain radiography as the preferred imaging modality.¹⁷

Learning points.

• Ureteric stent insertion has become an invaluable procedure in urology for temporary or permanent decompression of the upper urinary tract, however, it is not without possible complications such as stent migration.

• Enteric migration of a stent has not previously been reported.

• Bowel wall changes due to small vessels injury post pelvic radiotherapy can have a very late manifestation.

• Conservative management still plays an important role in the management of foreign bodies in the gastrointestinal tract, however, it has relative indications and absolute contraindications, and it is important to identify when active intervention in the form of endoscopy or surgery should be adopted.