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Collective Journal of Medicine

Original Research

Emergency Ureteroscopy for Obstructive Anuria Caused by Ureteric Stones


avatar Ahmed Mahfouz*,
12 Mar 2025

Affiliations
Department of Urology and Nephrology Centre in Mansoura University hospital Egypt.

*Corresponding Author: Ahmed Mahfouz, Department of Urology and Nephrology Centre in Mansoura University hospital Egypt.

Citation: Ahmed Mahfouz. Emergency Ureteroscopy for Obstructive Anuria Caused by Ureteric Stones. Collect J Med. Vol 2 (1) 2025; ART0065

Abstract

Objective: This study details our experiences of the efficiency and safety of emergency ureteroscopy as a treatment of ureteral stones presented in cases of acute renal failure.

Introduction: Acute Renal Failure (ARF) is a syndrome characterised by a rapid decline in the glomerular filtration rate and retention of nitrogenous waste products such as Blood Urea Nitrogen (BUN) and creatinine. Clinically, ARF is separated into 3 major categories: pre-renal, intrinsic, and post-renal. Post-renal ARF is most frequently caused by an obstruction of the urinary tract. Ureteral calculi are one of the most frequent causes of obstruction of the urinary tract. The emergency approach, within 24-48 hours of presentation to the emergency room, is both productive and cost-efficient. This study was presented as a moderated poster in EAU Urology in January 2024 and as a non-moderated poster in SIU in October 2023.

Patients and Methods: This retrospective study was conducted between May-December 2013. 4200 cases presented with anuria or oliguria, 743 of which were diagnosed as post-renal ARF. 389 patients (266 men and 123 women) with post-renal ARF with ureteric stones underwent emergency ureteroscopy and were included in the study. 70 patients (18%) had bilateral uteral stones, 148 patients (38%) had stones in the right ureter only, and in 171 (44%) in the left. There were 263 (57.3%) calculi in the pelvic ureter, 84 (18.3%) in the iliac ureter, and 112 (24.4%) in the lumbar ureter. Stone size ranged from 6-27 mm with a mean of 7.8 ± 7.9mm, as measured on pre-operative radiography of plain KUB, ultrasonography, and non-contrast spiral C.T, recorded as the maximal diameter.

Results: 432 of 459 procedures (95.1%) resulted in a total removal of stones. Failure to retrieve the stones was reported in 27 procedures (5.9%), including a failure to retrieve the stones because of severely impacted distal stones in 8 procedures (1.7%). These cases were managed with a nephrostomy tube, followed by an elective URS one week later, and were subsequently reported as stone-free. The hospital stay ranged from 1-14 days with a mean of 2.4 ± 1.7 days. The success rates for removing stones from the lower ureter, mid-ureter, and upper ureter were 93.5%, 82.1%, and 77.7% respectively (p value=.000). This procedure failed in 16 cases (3.4%) where the stone size was ≤1cm, and 11 cases (2.3%) where the stone size was >1cm (p-value 0.004). A higher failure rate was reported with pneumatic lithotripsy (10.6%) than laser (6.8%) (p-value 0.012). The mode of extraction also affected the success of the procedure, with a higher failure rate reported in procedures with the basket (7.3%) than those with forceps (1.7%) (p-value 0.029).

Conclusions: This study examined the efficacy of various methods of ureteroscopy management of ureteral stones in emergency situations. Emergency URS appears to be an efficient treatment modality for obstructive ureteral stones, especially distal ones. It is safe and effective, as well as providing immediate relief from pain and stone fragmentation. However, this procedure requires specific technical expertise and dedicated facilities, and more extensive studies with these features in place would be required to corroborate our findings.

Introduction

Acute Renal Failure (ARF) is a critical condition characterized by a rapid decline in kidney function, leading to the accumulation of nitrogenous waste products like Blood Urea Nitrogen (BUN) and creatinine. It is classified into three main types: pre-renal, intrinsic, and post-renal, with the latter often caused by urinary tract obstructions such as ureteral stones. These stones are a common source of severe colic pain and can result in calculus anuria—an emergency situation caused by bilateral ureteric impaction or unilateral obstruction in a solitary or only functioning kidney. Calculus anuria increases intra-pelvic pressure and risks permanent renal damage. The extent of impairment depends on factors like the nature, location, and duration of the obstruction. Studies have shown that significant renal dysfunction can occur within 24 hours of complete unilateral or bilateral ureteral obstruction, making early intervention essential. The primary goal in managing acute upper urinary tract obstruction is prompt restoration of urinary drainage, with definitive treatment preferred when feasible. While decompression is the priority in cases of renal failure, infection, or complete obstruction, ureteroscopy (URS) with intracorporeal lithotripsy is the treatment of choice for most obstructive lower and mid-ureteral stones. Emergency URS performed within 24–48 hours has proven effective and cost-efficient, and is being considered in updated clinical guidelines. However, despite increasing interest, there is limited data on the emergency use of URS for obstructive anuria. This study shares our experience assessing the safety and efficacy of emergency URS in such scenarios.

Materials and Methods

This retrospective study was conducted from May to December 2013 and included 4,200 patients with anuria or oliguria, of whom 743 were diagnosed with post-renal Acute Renal Failure (ARF). Emergency ureteroscopy was performed in 389 patients (266 men and 123 women) with ureteric stones. Anuria was the main complaint in 227 patients (58.3%), while 162 (41.6%) presented with oliguria; 170 (37%) reported loin pain and 60 (13%) had haematuria. Mean serum creatinine was 6.45 ± 4.1 mg/dL, and potassium 6.2 ± 0.36 mmol/L. Renal ultrasonography, KUB imaging, and non-contrast CT (in 67.5% of patients) were used for diagnosis. Bilateral stones were observed in 70 patients (18%), right-sided in 148 (38%), and left-sided in 171 (44%). Stone location included pelvic ureter (57.3%), iliac ureter (18.3%), and lumbar ureter (24.4%), with sizes ranging from 6–27 mm (mean 7.8 ± 7.9 mm).

Improvement Evaluation

Improvement was classified into three categories based on specific criteria:

  • Evident improvement: Defined as meeting one or more of the following criteria:
      Serum creatinine returned to normal based on the patient’s age and gender.
    • Creatinine clearance increased by 20 mL/min or more.
    • Complete weaning from dialysis.
  • Equivocal improvement: Defined as meeting one or both of the following criteria:
      Serum creatinine decreased but remained above the normal range for the patient’s age and gender.
    • The number of weekly dialysis sessions decreased.
  • No improvement: Patients who did not meet the criteria for evident or equivocal improvement were classified under this category.
Data Collection and Treatment Outcomes

Data collected included patient demographics, stone characteristics, type of treatment, and post-operative outcomes and complications.

  • Treatment failure: Defined as stones remaining in situ, residual stone fragments <3 mm, or failed access.
  • Treatment success: Defined as the complete absence of stones and fragments.
  • Impacted stones: Defined by the inability to pass a guidewire or catheter on initial attempts.
  • Stone-free status: Defined as the complete absence of calculi at the last follow-up.

Of the total calculi, 263 (57.3%) were in the pelvic ureter, 84 (18.3%) in the iliac ureter, and 112 (24.4%) in the lumbar ureter. Stone sizes ranged from 6 to 27 mm, with a mean size of 7.8 ± 7.9 mm, measured using plain KUB, ultrasonography, and non-contrast spiral CT. Refer to Table 1 for more details. A total of 84 patients (21.5%) underwent preoperative haemodialysis. Metabolic acidosis was found in 23 patients with a pH of less than 7.2 (27.3%), while 47 patients (55.9%) had severe hyperkalaemia (serum potassium >7 mmol/L). Additionally, 14 patients (16%) presented with volume overload, leading to respiratory and circulatory issues. Ureteroscopy was performed in this group after correcting electrolyte and acid-base imbalances. Ureteroscopy was conducted under..

Click to view Table 1: Stone Characteristics

Spinal anaesthesia, with preoperative antibiotics administered. A semi-rigid ureteroscope (sizes 8.5–10 CH or 9.5–11.5 CH) was guided by fluoroscopy. In 275 cases (59.9%), a ureteral catheter was placed and removed within 48 hours, while a double-J stent was inserted in 184 cases (40.1%). The operative time ranged from 25 to 80 minutes, with an average of 45 ± 28.5 minutes. Post-treatment monitoring included urine culture, serum creatinine levels, and electrolyte assessments. Radiologic follow-up involved a plain abdominal film on the first postoperative day to evaluate the initial stone-free rate and stent position, along with a non-contrast CT for cases with radiolucent stones or suspected residual fragments. Another plain abdominal film was performed before removing the double-J stent, typically after 15 to 30 days. Postoperative patient monitoring included vital signs, urine output, fluid balance, and the management of any complications until normalization. Patients were discharged once they had stable vital signs, spontaneous diuresis, effective pain control, independent mobility, and no significant complications. Follow-up appointments were scheduled every two weeks for the first two months, then every two months for a year, or as needed, particularly for patients with residual stones or those requiring secondary procedures. The study analysed patient characteristics and outcomes using IBM SPSS Statistics version 19 software (IBM Corp., Armonk, NY, USA). Outcomes were compared based on stone locations, gender, ureteroscopy types, and stent use, utilizing Pearson’s chi-square test for categorical variables and analysis of variance (ANOVA) for continuous variables. Statistical significance was set at p < 0.05. Since not all patients had complete data, analyses were performed on available data.

Results
Ureteroscopy Procedure

URS (Ureteroscopy) was performed under spinal anaesthesia with a semi-rigid ureteroscope and fluoroscopic guidance. Ureteral dilation was required in 43 cases (9.4%). Stone extraction was achieved mechanically in 144 procedures (31%) using graspers and in 74 (16.1%) using a basket. Pneumatic lithotripsy was employed in 123 cases (26.8%), while laser lithotripsy with Ho:YAG was used in 118 cases (25.7%). The overall stone-free rate was 95.1% (432 of 459 procedures), with 27 failures (5.9%). Among these, 8 cases (1.7%) involved severely impacted distal stones, which were managed with a nephrostomy tube followed by elective URS. Additional failures included 7 cases (1.5%) of stone migration, successfully treated with double-J stenting and either ESWL or alkalization therapy. Fragmentation failure occurred in 3 cases (0.6%), and minor ureteral perforations were observed in 9 cases (2%), all managed conservatively. Hospital stays ranged from 1 to 14 days, with an average of 2.4 ± 1.7 days. All patients experienced obstructive diuresis on the first day post-operation, with urine output ranging from 3,200 to 7,600 mL over 24 hours, which decreased to normal volumes (1,500–3,000 mL/day) within seven days. Renal function normalized in 63.0% of patients within three days and in 75.4% within seven days. One patient demonstrated significant renal function improvement by the 12-week follow-up. Hyperkalaemia resolved by the third postoperative day. Seven patients developed mild fever (37.2–37.5°C) on the first postoperative day, which subsided by day three. One patient had a high-grade fever (38.8°C) that resolved by day four following ceftriaxone sodium treatment. Regarding delayed complications, two patients (0.2%) developed ureteral strictures. One experienced stenosis post-lithotripsy, managed with balloon dilatation and a double-J stent for four weeks. The second patient underwent endoscopic ureterostomy with a stent in place for six weeks. Both cases had uneventful recoveries.

Complications

In our study, no severe complications were reported, with minor complications (modified Clavien classification grade 1) occurring in 24 cases (5.2%), including one case of ureteric avulsion. These results align with existing literature [19]. While there is no formal classification for ureteroscopy injuries, they are typically categorized by severity. Most complications are minor and manageable without surgery, whereas major complications require intervention and can have serious consequences. To prevent ureteral injuries, refined surgical techniques are essential. In particular, forced manoeuvres should be avoided during ureteroscope introduction, and good visibility must be maintained [20]. Complications were related to stone characteristics and patient factors. Minor injuries to the ureteral mucosa can occur during the use of guidewires and instruments, leading to perforation. Ureteral perforation has a 2% incidence, often associated with longer procedures. Most perforations can be treated with an endoscopic ureteral stent, and immediate double J stenting is effective in over 80% of cases [38]. If retrograde placement of a stent is not an option, complications can be managed through percutaneous nephrostomy and antegrade stent insertion. When endoscopic or percutaneous approaches are not viable, open surgery may be necessary [21]. According to [37], minor bleeding that impaired visibility was the most common reason for repeat ureteroscopy, although it was the primary complication in only one out of 346 procedures (0.3%). Ureteral stripping is a serious complication, but its incidence has decreased with experience. Most cases were linked to the forced extraction of calculi using a Dormia basket. Open surgery is often the preferred treatment for this complication [21]. Our study included one case of ureteral avulsion managed by open surgery. Post-operative infectious complications are more likely if urinary infections are present preoperatively. Routine antibiotic prophylaxis and ureteral stenting help mitigate these risks. However, stenting may not be necessary for patients who do not require ureteral dilation, potentially reducing operative time and costs [36]. The study’s main limitations include its retrospective design and lack of a control group, yet it had a robust sample size. The findings support the use of emergency ureteroscopy (URS) as a primary treatment option. Future multi-institutional studies would be beneficial, and patient counselling is highly recommended.

Conclusion

This report examines the emergency ureteroscopy management of ureteral stones in patients with calculus anuria. We conducted a retrospective chart review of procedures performed on patients with obstructive anuria, focusing on stone removal without prior drainage. Patient data included demographics, medical history, and stone characteristics such as size, location, density, laterality, and associated hydronephrosis. We recorded operative details, including procedure duration, type of anaesthesia, methods of stone disintegration, retrieval techniques, stenting, and complications. Post-treatment assessments included urinalysis, urine cultures, renal function tests, and evaluations of complications and hospital stays. Follow-up imaging involved an abdominal X-ray on post-operative day one to assess the initial stone-free rate and confirm stent placement. URS was performed under spinal anaesthesia using a semi-rigid ureteroscope with fluoroscopic guidance. Ureteral dilation was required in 43 cases (9.4%). Mechanical stone extraction was successful in 144 procedures (31%), pneumatic lithotripsy was performed in 123 cases (26.8%), and laser lithotripsy was used in 118 cases (25.7%). The overall stone-free rate was 95.1% (436 out of 459 procedures). Stone retrieval failed in 27 cases (5.9%), with 8 cases involving difficulties at the ureteric orifice and the remainder due to stone migration or fragmentation issues. Minor ureteral perforations were managed conservatively, avoiding the need for open surgery. The average hospital stay was 2.4 days. In conclusion, emergency URS is a safe and effective treatment for obstructive distal ureteral stones, providing immediate pain relief. This approach requires specialized expertise and well-equipped facilities, highlighting the need for further research to validate these findings.

References