Complications of Ureteral Stenting: A Case of Extrarenal Displacement

Introduction

As a global disease, the incidence and prevalence of ureteral calculi are increasing. The main clinical manifestation of ureteral calculi is intense lumbago pain on the same side, and the pain radiates to the groin. There are many methods for the diagnosis of ureteral calculi, among which abdominal X-ray and KUB ultrasound are usually used as primary screening means, while non-enhanced abdominal and pelvic CT scan is the criterion standard for diagnosis of ureteral calculi, with high specificity and sensitivity. Ureteral calculi are often complicated with many complications, which brings many challenges to the diagnosis and treatment of the disease, such as fever, urinary tract infection, perirenal infection, and urinary sepsis, which can endanger the life of patients in severe cases. In ureteral stones management, analgesic therapy plays an important role in initial treatment. The main treatment methods for ureteral stones currently include medication, extracorporeal shock wave lithotripsy (ESWL), and ureteroscopic laser lithotripsy. Among these, ureteroscopic laser lithotripsy is widely used and has a high stone clearance rate, but a double-J stent must be placed postoperatively to dilate the ureter and drain the stone [1].

Ureteral stent implantation is widely used in urology, and there are many complications [2], including ureteral perforation, ureteral avulsion or fracture, false canal formation, renal parenchyma perforation or rupture, and ureteral ectopia. After double-J type ureteral stent implantation, as a kind of foreign body, there can be many complications in vivo. Among them, the most common stent-related complication is “stent syndrome”, which mainly presents as abdominal pain, frequent urination, urgent urination, and suprapubic discomfort, and is sometimes accompanied by hematuria or incontinence, as well as ureteral stent rupture, stent ectopic placement, crusting, and stone formation. To avoid ureteral stent-related complications, it is necessary to select the appropriate stent size, determine the correct position of the stent with postoperative X-ray, and to perform regular telephone follow-up and timely removal.

In clinical work, as a complication after ureteral stent implantation, ectopic ureteral stentesis often occurs, and the ectopic location is usually unstable and diverse, which brings many uncertainties to the treatment of ureteroscopic holmium laser lithotripsy for ureteral calculi [3]. A misplacement of a ureteral stent into the inferior vena cava was reported [4]. There was also a report of a stent misplaced into the renal vein [5] and 2 articles described ureteral stents penetrating the renal parenchyma [6,7]. To the best of our knowledge, the present report is the first to describe a case of a ureteral stent completely misplaced to the outside of the kidney.

Case Report

A 54-year-old woman was admitted to the hospital for 1 day’s pain on the left side of the waist. The pain was intermittent colic, with nausea and vomiting. Physical examination showed percussion pain in the left kidney area. The ultrasound of the urinary system showed a left upper-ureter stone and left hydronephrosis. Computed tomography (CT) displayed left upper-ureteral calculi, left upper-ureteral dilatation, and left hydronephrosis. A routine urine analysis revealed 8 leukocytes per high-power field (hpf, 40× magnification; normal range: 0–5/hpf). Routine blood testing showed a white blood cell count (WBC) of 16.43×109/L (normal value: 4–10×109/L) and medium fine granulocyte percentage (NEUT%) of 94.4% (normal range: 50–70%). The primary diagnosis was left upper-ureteral stones accompanied by hydronephrosis. The second diagnosis was urinary tract infection.

After admission, the patient was given a 10-mg racanisodamine hydrochloride injection and a 100 ml 0.9% sodium chloride injection (once a day, intravenous infusion) to relieve pain. A 100-ml levofloxacin sodium chloride injection (containing levofloxacin 0.5 g, once a day, intravenous infusion) combined with a cefamandole nafate 2-g and a 100-ml 0.9% sodium chloride injection (intravenous infusion, once every 6 hours) was administered for anti-infection treatment. After 3 days of anti-infection treatment, the results of routine blood testing indicated that the infection indicators had returned to normal, and transurethral ureteroscopic holmium laser lithotripsy was performed under general anesthesia.

During the operation, a stone of about 0.8×0.6 cm was found in the upper segment of the left ureter. After using holmium laser to crush the stones into fine particles, a standard ureteroscope was introduced into the lower segment of the left ureter under the guidance of a guidewire, and a 5Fr ureteral stent (length 26 cm) was placed retrogradely along the guide-wire under direct vision. The patient felt restless and uneasy during the operation, and their cooperation during the surgery was poor. After placing the ureteral stent, the ureteroscope was withdrawn, and no ureteral stent was found in the bladder. The ureteroscope was guided with a guidewire to examine the ureter and renal pelvis, and no ureteral stent was found. Bedside X-ray examination: the ureteral stent was found between the left renal pole and the left diaphragm (Figure 1). Considering the patient’s restlessness during the operation and low cooperation during the procedure, the risk of immediately removing the ectopic ureteral stent is high. Therefore, a new double-J stent was again placed in the ureter for drainage, and the ectopic ureter stent is planned to be removed in the second stage. Postoperative CT confirmed that the double-J stents were completely misaligned outside the kidney, no hematoma bleeding was observed (Figure 2), and the patient had no obvious abdominal pain and other discomfort. Four weeks later, the patient returned to the hospital to take out the ureteral stent in normal position, and the double-J-type extra-renal stents were taken out laparoscopy. During the operation, slight adhesion around the double-J-type extra-renal stents was observed, and no changes in inflammation and bleeding were observed. After removal of the ureteral stent, the patient recovered well and was discharged (Figure 3).

Discussion

With the extensive development of minimally invasive techniques in the treatment of urinary system, ureteral stent implantation is widely used. At the same time, a variety of related complications have also appeared. Early complications include bladder irritation symptoms, hematuria, bacteriuria, fever and low back pain while late complications include ureteral erosion or fistulization, hydronephrosis, stent fracture, forgotten stent, transposition, and encrustation [8,9]. Complications caused by operation include ureteral perforation, ureteral avulsion, rupture, false canal formation, renal parenchyma perforation [6,7], ectopia of ureteral stent, renal vein perforation[5], urinary leakage, retroperitoneal hematoma, and abscess [10]. Ectopic ureteral stent is a rare complication about partial or total ureteral stent displacement. According to the anatomical structure, classifications of urinary system ectopia includes: gonadal (reproductive) vein[4], vena cava/right atrium [4], ureteral space [10], bladder space [10], extra-renal, and pulmonary arterial [11]. All the above types have been reported, but in the cases of ureteral stent ectopia, a ureteral stent completely misplaced to the outside of the kidney has never been reported. The author also encountered a case of ureteral stent implanted into gonadal vein during open nephrolithotomy. It was found in time in the operation and no serious result happened.

There are many causes of ureteral stent ectopia. The objective causes include stone incarceration, improper ureteral stent length, hydronephrosis, inflammatory, infection and so on. There are also many subjective causes: improper operation, the guide wire enters the false path but the ureteral stent is still pushed blindly. In this case, ectopic ureteral stent completely penetrated renal parenchyma to the outside of the kidney. It may be caused by improper operation, infection or high intraoperative perfusion pressure. In addition, the patient’s restlessness during the surgery, poor cooperation with the procedure, and the anesthetist’s lack of coordination during anesthesia are also important reasons for the occurrence of such events. Due to the poor infrastructure conditions of local hospitals, we only assessed the stent position using bedside ultrasound and did not confirm the stent position under fluoroscopy during the procedure.

In retrograde double-J stent placement, compared with the closed-tip stent insertion, a double-J stent pushed forward through the guide wire inserted in advance can reduce the risk of renal parenchyma perforation [7].

Renal perforation caused by double-J stent implantation or double-J stent pushed to the outside of the kidney or the ureter can be diagnosed by B ultrasound, bedside X-ray machine or CT examination. To avoid complications such as ureteral stricture or leakage, infection, it is necessary to reimplant a ureteral stent for drainage.

The ectopic ureteral stent outside the kidney can be removed at a scheduled time according to the type of ectopia. The author believes that the ectopic ureteral stent in ureteral, bladder space or outside the kidney should be removed by laparoscopy at 4–6 weeks; A partial ectopic ureteral stents can be taken out through ureteroscopy and the ureteral stent should be implanted again immediately. The ureteral stent in the vascular cavity must be removed immediately to avoid more serious complications [12]. In this case, we did not immediately remove the displaced ureteral stent, mainly because the patient was restless during the surgery and did not cooperate well; we lacked similar surgical experience and relevant expertise in handling such cases. The patient did not exhibit postoperative symptoms such as bleeding, infection, or pain; furthermore, when assessing the displacement of the ureteral stent into the retroperitoneal space, it is relatively safe compared to other locations (such as the anterior abdominal cavity). Therefore, we adopted a more cautious approach and chose to remove the ectopic ureteral stent after 4 weeks to avoid certain risk events. In order to reduce the risk of readmission and anesthesia for the patient, the ureteral stent was removed after 4 weeks through ureteroscopy, and the ectopic ureter was taken out through laparoscope with general anesthesia. During the operation, there was slight adhesion around the stent, no bleeding, and the renal capsule was complete. There was no difficulty in taking out the stent. The patient had no discomfort during and after operation.

Ectopic ureteral stents are frequently reported, and the location, clinical presentation, and treatment of ectopic stents often vary. Dunev et al [13] reported that it is very rare for ureteral stents to become knotted after implantation and not be removed. As we have reported, after ectopic ureteral stenting, a ureteral stent needs to be re-inserted for drainage. In previous reports of ectopic ureteral stenting, complications such as bleeding and kidney damage have often been observed in patients receiving stenting [5,7]. However, in our report, the patient did not show any particular discomfort, which greatly confuses the clinical diagnosis of ectopic ureteral stents and requires us to carefully examine and confirm the location of the ureteral stents during surgery. From our report, we have summed up and reflected on many experiences. First of all, ureteral stenting, as a common internal drainage method after holmium laser lithotripsy, has early and late complications. Regular telephone follow-up of patients is required to remove the ureteral stenting in time to avoid serious complications. Secondly, as a local hospital, a lot of equipment and infrastructure are not in place, which restricts our timely inspection. However, we must learn to deal with any contingencies and deficiencies. Third, as a local hospital doctor, you need to continuously improve your surgical skills, accumulate rich experience, and provide better services for patients.

Conclusions

Through in-depth analysis of cases, this study reveals the causes of ectopic ureteral stents and provides practical experience in the treatment of ectopic stents, with a view to promoting the improvement of medical quality and ensuring the safety and rehabilitation of patients. In addition, this study illustrates the importance of careful intraoperative examination and postoperative follow-up by sharing a case of an ec-topic ureteral stent outside the kidney, as stent displacement can be an early or late complication.