Stesura Seveso Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 1 ORIGINAL PAPER classifying it as a urological emergency (1, 2). Recent glob- al estimates highlight the prevalence of urolithiasis, empha- sizing the increasing need for efficient and safe treatment strategies (1). As the incidence of ureteral stones varies, the need for emergency intervention due to acute obstruction becomes a consistent clinical challenge. Advances in endourological techniques, particularly emergency ureteroscopy (URS) using semirigid uretero- scopes, have revolutionized the management of ureteral stones (3, 4). Emergency URS, defined by the immediate intervention required to address acute ureteral obstruc- tion and its associated complications, has become a pri- mary modality for diagnosis and treatment, including ureteroscopic lithotripsy (3, 5). This shift towards mini- mally invasive approaches has improved patient out- comes; however, it is crucial to acknowledge and address the potential for adverse events, especially in emergency settings where patient acuity, the degree of obstruction, and resource availability may impact outcomes (3). The use of pneumatic lithotripsy is a common method for stone fragmentation. The spectrum of adverse events associated with emer- gency URS ranges from minor, such as mucosal abrasions and stone migration, to more severe events like ureteral perforation or avulsion (3, 4). While advancements in URS technology and surgical techniques have improved stone-free rates (approaching 90-97%), the emergency nature of the procedure can influence the incidence and severity of complications (4-6). Specifically, in the setting of acute obstruction, challenges include increased tissue edema, altered ureteral anatomy, and the potential for infection, which may affect the surgeon's ability to man- age the stones. Prior research has identified several factors associated with adverse events in URS for ureteral stone treatment (4, 6-9). These include stone characteristics (size, densi- ty, location), patient-specific variables (age, comorbidi- ties, and anatomy), and procedural factors (instrument type, surgical experience, and the presence of infection). In the context of emergency URS, the interplay of these factors requires specific investigation to optimize patient care. Despite the importance of this topic, there is a rela- tive lack of research focusing on adverse events in emer- gency URS settings, particularly within the context of resource-limited environments. This study aims to ana- Background: Data on complications associat- ed with emergency ureteroscopy for ureteral stones are limited, particularly in developing countries. This study investigates factors contributing to complications in emergency ureteroscopy utilizing a pneumatic semirigid uretero- scope (URS). Materials and methods: This retrospective analysis included 266 patients with ureteral stones who underwent emergency ureteroscopy using a pneumatic semirigid URS from 2018 to 2023. We extracted comprehensive data on patient demograph- ics, stone characteristics, intraoperative and postoperative com- plications, and stone-free rate (SFR) from medical records, sub- sequently subjected to statistical analysis. Factors linked to com- plications were explored through univariate and multivariate analyses. Results: The mean stone size was 9.1 ± 4.9 mm, with the majori- ty (n = 181, 71.3%) located in the mid-ureter. The mean opera- tive duration was 57.7 ± 7.3 minutes. The overall complication rate was 10.2%, with intraoperative complications in 16 patients (6.0%), including mucosal damage (3.4%), stone up-migration (3.0%), and one ureteral perforation (0.4%). Postoperative com- plications occurred in 13 patients (4.9%), primarily fever (2.6%), followed by hematuria (1.1%). Additional complications included febrile urinary tract infections (UTIs), pyelonephritis, and one mortality. The overall SFR was 85.3%, with 39 patients (14.7%) demonstrating residual stones. Significant predictive factors for complications included larger stone size (Adjusted Odds Ratio [AOR]: 1.3; 95% Confidence Interval [CI]: 1.15-1.39, p < 0.0001) and proximal ureteral stones (AOR: 4.9; 95% CI: 1.31- 18.23, p = 0.0182). Conclusions: Emergency ureteroscopy using a semirigid URS demonstrated favorable outcomes in treating ureteral stones, characterized by minimal complications and an acceptable SFR. Emphasizing appropriate instrument selection, surgical expert- ise, and technique is crucial in minimizing adverse events, par- ticularly for large and upper ureteral stones. KEY WORDS: Emergency ureteroscopy, Pneumatic semirigid ureteroscope, Surgical complications, Ureteral stones, Urolithiasis. Submitted 24 February 2025; Accepted 25 February 2025 INTRODUCTION Ureteral stones represent a significant and growing public health burden, necessitating timely and effective interven- tions due to the acute pain associated with ureteric colic, Complications in emergency ureteroscopy for ureteral stone treatment: A retrospective study Khalil Al-Naggar 1, Faisal Ahmed 1, Khaled Al-Kohlany 2, Ibrahim Alnadhari 3, 4 1 Department of Urology, School of Medicine, Ibb University, Ibb, Yemen; 2 Department of Urology, College of Medicine, Sana'a University, Sana'a, Yemen; 3 Urology Section, Department of Surgery, Al Wakra Hospital, Hamad Medical Corporation, Al Wakra, Qatar; 4 Department of Surgery, College of Medicine, Qatar University, Doha, Qatar. DOI: 10.4081/aiua.2025.13759 Summary Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 K. Al-Naggar, F. Ahmed, K. Al-Kohlany, I. Alnadhari 2 lyze the adverse events and predictive factors associated with emergency ureteroscopy using a pneumatic semi- rigid URS for ureteral stones, with the goal of improving treatment efficacy, enhancing patient safety, and develop- ing targeted strategies to mitigate the risk of complica- tions. The findings of this study may inform clinical prac- tice guidelines, improve patient counseling, and optimize resource allocation in emergency urological care. MATERIALS AND METHODS Study design and setting This retrospective study was conducted at Ibb University Hospitals, Ibb, Yemen. The study cohort comprised 266 patients who underwent emergency transurethral ureterolithotripsy (TUL) using semirigid ureteroscopes from November 2018 to September 2023. Emergency URS was defined as a procedure performed for acute ureteral obstruction due to symptomatic stones in patients presenting with: (1) severe ureteric colic unresponsive to conservative management; (2) acute renal impairment, indicated by a serum creatinine increase of ≥ 0.5 mg/dL or a calculated eGFR decrease of ≥ 15 mL/min within 24-48 hours; or (3) symptoms suggestive of urinary tract infec- tion with systemic inflammatory response syndrome or suspected pyonephrosis requiring urgent intervention. Ethical approval was obtained from the Ibb University ethics committee, following the principles of the Helsinki Declaration, with a waiver for individual patient consent due to the study's retrospective nature. This investigation focused on emergency URS as a first- line treatment for ureteral stones that were refractory to conservative management or complicated by severe con- ditions. Additionally, patients with severe uremia or sep- sis due to obstruction who underwent urinary decom- pression via percutaneous nephrostomy or ureteral stent- ing prior to definitive URS were included in the analysis. Inclusion criteria Participants included adult patients (aged 18 years and older) presenting with symptomatic ureteral calculi and subsequently undergoing emergency semirigid URS at our facility. All patients in the cohort presented with acute symptoms requiring emergent intervention, as defined above. Exclusion criteria Patients were excluded if they met any of the following criteria: (1) established ureteral strictures precluding safe URS access; (2) active UTIs (requiring initial treatment and exhibiting clinical signs of sepsis that were not direct- ly related to the acute obstruction); (3) pregnancy; (4) severe orthopedic deformities that would have made proper positioning for URS impossible; (5) documented coagulation disorders that could not be medically cor- rected prior to intervention; or (6) those undergoing URS for non-emergency indications (e.g., elective stone removal, diagnostic ureteroscopy). Patients with documented prior URS or other ureteral interventions were included as long as they met inclusion criteria. Preoperative assessment Comprehensive preoperative assessments were meticulous- ly conducted to gauge the severity of the patients' acute presentation and guide treatment decisions. This included a detailed review of medical and surgical histories, including medication use (especially anticoagulants), prior urologic interventions, and comorbid conditions (diabetes, hyper- tension, cardiovascular disease). Clinical examinations focused on assessing vital signs (temperature, heart rate, blood pressure, respiratory rate) and signs of systemic ill- ness, and thorough abdominal examinations. Investigations included: (1) renal function tests (blood urea nitrogen, cre- atinine); (2) complete blood count with differential; (3) uri- nalysis with microscopic examination to assess for the pres- ence of hematuria, pyuria, and bacteriuria; and (4) urine culture and sensitivity if a UTI was suspected. Imaging eval- uation comprised: (1) urinary tract ultrasound to assess for hydronephrosis, stone presence/location, and any evidence of renal abscess; (2) plain radiography (KUB) to assess for radiopaque stones; and (3) non-contrast computed tomogra- phy (NCCT) scans of the abdomen and pelvis to accurately characterize the stone, assess the degree of hydronephrosis, and evaluate for other potential etiologies. Stone character- istics, including dimensions (in mm), location (proximal, mid, or distal ureter), and Hounsfield units (HU) were evalu- ated using NCCT. The degree of hydronephrosis was grad- ed based on the Society of Urodynamics, Female Urology, and Urogenital Reconstruction (SUFU) guidelines (mild, mod- erate, severe). Surgical procedure All TUL procedures were performed by experienced urol- ogists with a minimum of 10 years of experience in endourology, including URS. The TUL procedure was performed under either general or regional anesthesia based on patient and surgeon preference and clinical assessment. A single intravenous dose of prophylactic antibiotics (Ceftriaxone) at a dose of one gram was admin- istered before the induction of anesthesia and continued for 24-48 hours postoperatively, based on institutional protocols. Patients were positioned in the standard dorsal lithotomy position. The procedure commenced with rigid cystoscopy to visualize the bladder and identify the ureter- al orifice. A hydrophilic guidewire was then advanced into the ureter under direct vision. A semirigid ureteroscope (6-Fr, Karl Storz, Tuttlingen, Germany) was employed, and stone fragmentation was accomplished using a Swiss LithoClast® Pneumatic Lithotriptor. Ureteroscopic proce- dures were performed by the experienced urologists. Retrieval of stone fragments was attempted with a retrieval basket or grasping forceps, especially for larger fragments. Smaller fragments (< 2 mm) were often left to pass spon- taneously if it was deemed safe (absence of significant obstruction, no evidence of severe ureteral injury). Double- J (DJ) ureteral stents were placed at the discretion of the operating surgeon based on the clinical scenario, which was the presence of edema, anticipated difficulty with stone passage, or ureteral injury and were usually left in situ for 5-10 days unless complications arose. The reasons for stent placement were documented in the patient charts. For patients with significant hydronephrosis, impacted stones, solitary kidney, or those with pre-opera- Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 3 Emergency ureteroscopy tive uremia, the DJ stent was retained for 4-6 weeks to facilitate optimal healing and prevent obstruction. Indwelling urethral catheters were not routinely inserted, except in cases where significant bleeding was expected, or for patients with comorbidities that required it. Operative time was recorded, defined as the time from insertion of the cystoscope to the completion of the pro- cedure and removal of instruments. Fluoroscopy was used during the procedure. Postoperative assessment Postoperatively, patients received appropriate analgesics (non-steroidal anti-inflammatory drugs, opioids) and antiemetics as required. Alpha-blockers were adminis- tered as per clinical needs. Most patients were discharged within 24 hours, contingent on a stable clinical condition, absence of significant complications, and adequate pain control. Uremic patients were discharged only after labo- ratory and clinical parameters were normalized and after consultation with a nephrologist. Pain was assessed using a validated pain scale (e.g., visual analog scale). All patients were instructed to report any symptoms of fever, persistent pain, or changes in urinary function. All patients underwent plain radiography (KUB) and abdominal ultrasound two days after surgery. Success was defined as the absence of residual stones larger than 2 mm, resolution of symptoms (colic), and improvement in renal function in patients presenting with renal impair- ment, or in the absence of complications. An additional ultrasound was conducted three months after the proce- dure. Stone clearance was confirmed by the absence of residual stones on radiological imaging, including radiog- raphy, ultrasound, or non-contrast CT scans within the first three months following URS. Follow-up imaging was based on clinical need and according to the established protocol. Intraoperative complications were assessed using a mod- ified version of the Satava classification system (10), specifically adapted for URS. Grade 1 complications were considered minor and did not negatively impact patient outcomes. This category included: (1) minimal mucosal injuries (observed only); (2) mild bleeding that was self- limited or easily controlled with irrigation; (3) instrument malfunctions that were easily and quickly resolved (e.g., guidewire issues, irrigation problems); and (4) proximal stone migration that could be managed with a change in technique or observation. Grade 2 complications necessi- tated some form of medical intervention. These were fur- ther subdivided into: Grade 2a, which included compli- cations managed intraoperatively through endoscopic techniques (e.g., additional stone manipulation, repeat lithotripsy, stent placement due to ureteral injury), and Grade 2b, requiring subsequent endoscopic re-treatment within the same hospital admission. Examples included: (1) difficulties in accessing the ureter requiring use of alternative techniques (e.g., change of guidewire); (2) sig- nificant bleeding requiring prolonged irrigation, the use of hemostatic agents (e.g., topical thrombin); (3) extra- ureteral stone migration; (4) mucosal injuries such as false passages or thermal injuries (requiring stent place- ment); and (5) ureteral perforation requiring stent place- ment or other interventions, but without the need for open or laparoscopic surgery. Grade 3 complications were considered more severe and required open or laparoscopic surgical intervention. This category com- prised: (1) severe bleeding requiring blood transfusion or surgical exploration; (2) persistent instrument malfunc- tions that prevented completion of the procedure; (3) inability to access the ureter or stone despite multiple attempts and the use of various techniques; (4) ureteral perforation with extravasation requiring open or laparo- scopic repair; (5) ureteral intussusception; and (6) ureter- al avulsion. Postoperative complications were systemati- cally classified by the operating surgeon using the Modified Clavien Classification System (MCCS) (11). Each complication was evaluated according to the modified Clavien grading scale. In instances where patients experi- enced multiple complications, each was graded individu- ally based on its severity. Main outcomes The primary outcome of this study was the prevalence of intraoperative and postoperative adverse events, while the secondary outcome aimed to identify factors associat- ed with these complications. Data collection Data collected included: (1) patient demographics [age, gender, body mass index (BMI)]; (2) comorbidities (dia- betes mellitus, hypertension, coronary artery disease, chronic kidney disease, etc.) were recorded using the Charlson Comorbidity Index; (3) previous treatments such as extracorporeal shock wave lithotripsy (ESWL) and other prior interventions for ureteral stones; (4) radiologi- cal characteristics of stones [Hounsfield units (HUs), size (in mm), location (proximal, mid, distal ureter), number of stones, laterality (left/right), and degree of hydronephrosis (SUFU grading)]; (5) presenting symptoms (colic, infec- tion, renal insufficiency), including the duration of symp- toms before the presentation; (6) treatment outcomes; (7) intraoperative and postoperative complications (classified as described above); and (8) stone-free rates (SFR) at 2 days and 3 months. The S.T.O.N.E. scoring system was calcu- lated based on preoperative non-contrast CT findings, incorporating Size, Topography, Obstruction, Number, and Evaluation of Hounsfield units (HU) (12). Data was extracted from electronic medical records and from the patient's medical chart. Statistical analysis Statistical analyses were conducted using SPSS version 22 (IBM, Armonk, NY). Continuous variables are present- ed as means ± standard deviations or medians with interquartile ranges (IQR) and compared using the Student’s t-test for normally distributed data and the Mann-Whitney U-test for non-normally distributed data. Categorical variables are reported as frequencies and per- centages and analyzed using Pearson's chi-square test or Fisher's exact test, where appropriate. Univariate analy- sis was performed to identify potential risk factors asso- ciated with intraoperative and postoperative complica- tions. Variables with a p-value < 0.2 in univariate analy- sis were then considered for inclusion in a multivariate logistic regression model to identify independent predic- Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 K. Al-Naggar, F. Ahmed, K. Al-Kohlany, I. Alnadhari 4 tors of complications. The multivariate model included variables that were clinically relevant to the outcome. Results were reported as adjusted odds ratios (AORs) with 95% confidence intervals (CIs). A p-value < 0.05 was con- sidered statistically significant. RESULTS This study included a total of 266 patients, with a mean age of 47.7 ± 15 years and a median age of 44 years (range: 18 to 91 years). The cohort was predominantly male, com- prising 192 individuals (72.2%). The mean weight of the patients was 72.7 ± 9.8 kg, with a median of 72 kg (range: 46 to 110 kg). The most common presenting symptom was acute flank pain, reported by 168 patients (63.2%), fol- lowed by fever in 60 patients (22.6%) and hematuria in 38 patients (14.3%). The majority of stones were located on the right side (n = 141, 53.0%), and a history of prior ESWL was noted in 31 patients (11.7%). Comorbid condi- tions included diabetes in 13 patients (4.9%) and hyper- tension in 10 patients (3.8%) (Table 1). Preoperative CT scans indicated a mean stone size of 9.1 ± 4.9 mm and a median size of 8 mm (range: 4 to 24 mm). Multiple stones were identified in 132 patients (52.0%), with an average of 1.6 ± 0.6 stones per patient and a median of 2 stones (range: 1 to 3). The mean stone density was measured at 523.4 ± 281.4 HU, with a medi- an of 458.5 HU (range: 0 to 1351 HU). Hydronephrosis severity was classified as mild in 188 patients (74.0%), moderate in 52 patients (20.5%), and severe in 14 patients (5.5%). The majority of ureteral stones were located in the mid- ureter (n = 181, 71.3%), while distal and proximal ureter- al stones were present in 68 patients (26.8%) and 5 patients (2.0%), respectively. All patients underwent urgent ureteroscopy utilizing semirigid ureteroscopes; however, the procedure was unsuccessful in 7 patients (2.63%), resulting in the placement of a double J stent, with successful completion of the procedure one week later. The mean operative time was 57.7 ± 7.3 minutes, with a median of 55 minutes (range: 45 to 77 minutes) (Table 2). Table 1. Patients demographic characteristics. Variable a Subgroup Total (266) Complications OR (95% CI) p-value b no (239) Yes (27) Age (year) Mean ± SD 47.7 ± 15.0 47.4 ± 15.0 50.0 ± 15.2 1.01 (0.99-1.04) 0.386 Gender Male 192 (72.2) 170 (71.1) 22 (81.5) Ref 0.362 Female 74 (27.8) 69 (28.9) 5 (18.5) 0.56 (0.18-1.43) Weight (kg) Mean ± SD 72.7 ± 9.8 72.9 ± 9.6 71.0 ± 10.9 0.98 (0.94-1.02) 0.343 History of diabetes No 253 (95.1) 230 (96.2) 23 (85.2) Ref 0.040 Yes 13 (4.9) 9 (3.8) 4 (14.8) 4.44 (1.13-14.85) History of hypertension No 256 (96.2) 230 (96.2) 26 (96.3) Ref 1.000 Yes 10 (3.8) 9 (3.8) 1 (3.7) 0.98 (0.05-5.54) History of previous ESWL No 235 (88.3) 213 (89.1) 22 (81.5) Ref 0.392 Yes 31 (11.7) 26 (10.9) 5 (18.5) 1.86 (0.59-5.01) Symptoms at Presentation Acute flank pain 168 (63.2) 151 (63.2) 17 (63.0) Ref Hematuria 38 (14.3) 36 (15.1) 2 (7.4) 0.49 (0.08-1.83) 0.359 Fever 60 (22.6) 52 (21.8) 8 (29.6) 1.37 (0.53-3.27) 0.495 SD: standard deviation; ESWL: Extracorporeal shock wave lithotripsy; OR: odds ratio, CI: confidence interval. a Data were presented as count (percentage) or mean (standard deviation). b P-Valus of < .05 were blooded and considered statistically significant and analyzed by Student’s- t-test and chi-square test. Table 2. Radiologic and operative characteristics. Variable a Subgroup Total (266) Complications OR (95% CI) p-value b no (239) Yes (27) Stone size (mm) Mean ± SD 9.1 ± 4.9 8.4 ± 4.4 15.5 ± 5.1 1.31 (1.20-1.44) < 0.001 Stone density (HU) Mean ± SD 523.4 ± 281.4 517.4 ± 286.7 577.0 ± 226.6 1.00 (1.00-1.00) 0.297 Hydronephrosis degree Mild 195 (73.3) 177 (74.1) 18 (66.7) Ref 0.712 Moderate 55 (20.7) 48 (20.1) 7 (25.9) 1.43 (0.53-3.50) 0.447 Severe 16 (6.0) 14 (5.9) 2 (7.4) 1.40 (0.21-5.58) 0.669 Stone location Distal 70 (26.3) 68 (28.5) 2 (7.4) Ref Middle 188 (70.7) 169 (70.7) 19 (70.4) 3.82 (1.07-24.40) 0.077 Proximal 8 (3.0) 2 (0.8) 6 (22.2) 102.00 (14.77-1188.43) < 0.001 Operative time (min) Mean ± SD 55.7 ± 8.9 55.9 ± 9.0 53.6 ± 8.5 0.97 (0.92-1.02) 0.208 S.T.O.N.E. Score Mean ± SD 8.0 ± 1.8 7.8 ± 1.7 10.0 ± 1.2 2.43 (1.77-3.55) < 0.001 Stone number Single 122 (45.9) 120 (50.2) 2 (7.4) Ref < 0.001 Multiple 144 (54.1) 119 (49.8) 25 (92.6) 12.61 (3.65-79.44) HU: Hounsfield Units; SD: standard deviation; OR: Odds ratio, CI: confidence interval. a Data were presented as count (percentage) or mean (standard deviation). b P-Valus of < .05 were blooded and considered statistically significant and analyzed by Student’s- t-test and chi-square test. Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 5 Emergency ureteroscopy The overall complication rate was 10.2%. Intraoperative complications were observed in 16 patients (6.0%), pri- marily consisting of mucosal damage (n = 9, 3.4%), stone up-migration or retropulsion (n = 8, 3.0%), and ureteral perforation (n = 1, 0.4%). Postoperative complications occurred in 13 patients (4.9%), with fever being the most prevalent (n = 7, 2.6%), followed by hematuria in 3 patients (1.1%). Additional complications included febrile urinary tract infection, pyelonephritis, and one case of mortality (n = 1, 0.4%). Importantly, there were no significant intraoperative complications, such as ureteral avulsion. Among the postoperative complica- tions, two notable cases emerged: one patient developed pyelonephritis and was treated with intravenous antibiotics, while another patient succumbed to diabetic ketoacidosis compounded by emphysematous pyelonephritis, sepsis, and multiorgan failure. The overall SFR at follow-up was 85.3%, as verified by postoperative radiographic exami- nations; however, 39 patients (14.7%) exhibited residual stones and required additional endourological interven- tions (Table 3). Factors associated with complications Univariate analysis identified several factors significantly associated with complications, including a history of dia- betes (p = 0.040), larger stone size (p < 0.001), presence of multiple stones (p < 0.001), S.T.O.N.E. score (p < 0.001), and stones located in the proximal ureter (p < 0.001). In multivariate analysis, the key predictive factors for com- plications included large stone size AOR: 1.3; 95% Confidence Interval (CI): 1.15-1.39, p < 0.0001) and the proximal ureter location of stones (AOR: 4.9; 95% CI: 1.31-18.23, p = 0.0182) (Table 4). DISCUSSION URS has seen significant advancements, establishing itself as a safer and more effective approach for the manage- ment of urinary tract stones. Innovations in smaller ureteroscopes and the development of advanced instru- ments and energy sources have improved procedural out- comes; however, complications remain a concern, emphasizing the need to identify predictive factors asso- ciated with these risks (4, 5). This study examines the complications and outcomes associated with emergency semirigid URS in managing ureteral calculi within a resource-limited setting. Our findings show that semirigid URS yields excellent out- comes, exhibiting high stone clearance rates and minimal complications, with larger stone sizes and proximal stone locations identified as significant predictors of adverse events. The variability in intraoperative complication rates among studies can be attributed to several factors, includ- ing differences in study design, patient demographics, stone characteristics, surgical techniques, and the expert- ise of the surgical teams. Our investigation revealed an overall intraoperative complication rate of 6.0%, com- prising mucosal damage (3.4%), stone upward migration (3.0%), and ureteral perforations (0.4%). For compari- son, Geavlete et al. reported an intraoperative complica- tion rate of 3.6% in a cohort of 98 cases, highlighting mucosal injuries and stone migrations (13). Tanriverdi et al. documented a higher complication rate of 8%, which included transient hematuria, mucosal erosion, and ureteral perforations (4). The lower complication rate observed in our study may reflect the experience of the surgical team, as more complex cases are frequently Table 3. Intraoperative and postoperative complications characteristics. Complication * N (%) Intraoperative 16 (6.0%) Mucosal damage 9 (3.4%) Stone up-migration or retropulsion 8 (3.0%) Ureteral perforations 1 (0.4%) Postoperative 13 (4.9%) Fever (Grade I) 7 (2.6%) Hematuria (Grade I) 3 (1.1%) Febrile UTI (Grade II) 1 (0.4%) Pyelonephritis (Grade III) 1 (0.4%) Death (Grade Ⅴ) 1 (0.4%) UTI: Urinary tract infection. * Some patients had multiple complication. Table 4. Predictive factors for complications in Multivariate regression analysis. Variable a Subgroup No (239) Yes (27) Cured OR p-value Adjusted p-value b (95% CI) OR (95% CI) History of diabetes No 230 (90.9) 23 (9.1) Ref 0.235 - - - Yes 9 (69.2) 4 (30.8) 2.80 (0.46-14.61) - Stone size (mm) Mean ± SD 8.4 ± 4.4 15.5 ± 5.1 1.18 (1.05-1.35) 0.007 1.3 (1.15-1.39) < 0.0001 Stone number Single 120 (98.4) 2 (1.6) Ref 0.918 - - - Multiple 119 (82.6) 25 (17.4) 1.12 (0.15-11.70) - Stone location Distal 68 (97.1) 2 (2.9) Ref - - Mid 169 (89.9) 19 (10.1) 1.03 (0.23-7.18) 0.973 - - Proximal 2 (25.0) 6 (75.0) 10.97 (1.18-150.52) 0.046 4.9 (1.31-18.23) 0.0182 S.T.O.N.E. Score Mean ± SD 7.8 ± 1.7 10.0 ± 1.2 1.54 (0.90-2.65) 0.113 - - SD: standard deviation; CI: confidence interval; OR: Odds ratio. a Data were presented as count (percentage) or mean (standard deviation). b P-Valus of < .05 were blooded and considered statistically significant and analyzed by Multivariate regression analysis test. Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 K. Al-Naggar, F. Ahmed, K. Al-Kohlany, I. Alnadhari 6 referred to the capital city, where a specialized urology team with advanced equipment operates. Among intraoperative complications, ureteral mucosal injury was the most commonly reported, consistent with findings from previous studies (4, 14). Such injuries often occur during the introduction of operative instruments, including the ureteroscope and guide wires. Importantly, all complications were managed conservatively, avoiding the need for open surgery and resulting in favorable out- comes. The upward migration of stones, observed in 3.0% of cases, is often linked to larger stones during URS, partic- ularly when using pneumatic lithotripsy. Proximal ureteric stones exhibit migration rates approaching 30%, underscoring the importance of anti-retropulsion devices (4, 14). The advent of devices like the Stone Cone and various entrapment nets aims to mitigate the risk of stone migration during ureteroscopic procedures (8). Importantly, our study noted a low incidence of ureteral perforations at 0.4%. These perforations typically arise due to excessive force during the advancement of the ureteroscope. The incorporation of smaller-caliber ureteroscopes can facilitate safer navigation through nar- rowed regions of the ureter (9, 15). Predicting complica- tions, particularly in urgent cases, necessitates considera- tion of potential anatomical variations, such as constrict- ed ureteric lumens, prevalent in a significant percentage of patients undergoing urological procedures (15, 16). Postoperative complication rates are notably variable in the literature. Recent reviews, including a study by De Coninck et al., reported that postoperative febrile events and urinary tract infections (UTIs) can vary from 0.2% to 15%, with renal colic rates ranging from 1.1% to 10.2%. In our cohort, the overall postoperative complication rate was 4.9%. Fever was the most common complication (2.6%), followed by hematuria (1.1%), with isolated cases of febrile UTI, pyelonephritis, and mortality (0.4%). These results resonate with findings from Perez et al., who simi- larly identified fever as the predominant postoperative complication (17). Despite these occurrences, we did not document any severe postoperative complications aside from one case of urosepsis requiring hospitalization and another involving a patient with diabetes who succumbed to multiorgan failure. The risk of severe outcomes, partic- ularly those associated with urosepsis, remains a critical concern, reinforcing the necessity for adherence to safety protocols and effective management strategies during interventions (3). Overall, practical experience, judicious patient selection, thorough preoperative assessment, and close follow-up for high-risk patients likely contribute to the low incidence of complications observed in our study. Our findings reported an overall stone-free rate (SFR) of 85.3% post-URS, consistent with results from other stud- ies, including Alameddine et al. (89.0%), Shrestha et al. (80.5%), Kim et al. (85.7%), and Sirirak et al. (89.68%) (18-21). Conversely, a study conducted in Ethiopia revealed a notably lower SFR of 54.7%, attributed to lim- ited experience among surgical staff and less advanced equipment (22). The inconsistency in the definition of SFR across studies raises questions about the comparabil- ity of reported outcomes, as divergent imaging tech- niques can yield varied results. The report identifies a mean patient age of 47.7 ± 15 years, with a male predominance, reflecting trends observed in other geographic regions such as Ethiopia, Iraq, and Egypt (22-25). Notably, our analysis revealed no significant correlation between age and complication rates, aligning with observations from Mustafa et al. (26). While some studies suggest an increased risk of compli- cations with advancing age (27, 28), our findings indicate that age alone may not serve as a critical determinant of adverse outcomes. Regarding gender, we found no statistically significant cor- relation with complications in our study, although previ- ous research suggests gender may influence stone clear- ance rates and complication risks (7, 29). Comorbid con- ditions, particularly diabetes mellitus, were identified as contributing factors to postoperative complications. This aligns with historical data suggesting that diabetes increas- es the risk of adverse outcomes following URS (3, 30, 31). However, the small sample size limits our ability to draw definitive conclusions regarding these associations. Moreover, our findings support the notion that stone characteristics – such as size, location, and density – serve as predictors of complications. Larger stone size and proximal location were shown to be significant predictors in our multivariate analysis, corroborating previous liter- ature (22, 24, 32, 33). The rationale for this association is that larger stones necessitate longer operative times and greater irrigation volumes, increasing the likelihood of complications. Interestingly, we found no statistical cor- relation between stone density and complications, poten- tially due to the limited sample size available for analysis. While the American Urological Association recommends flexible URS for larger upper ureteric calculi, evidence suggests that semirigid URS can effectively treat upper ureteric stones, including larger and impacted stones (24, 34). Our study reinforced the importance of con- sidering stone location as a predictive factor for compli- cations – echoing findings from prior studies (22, 25). The presence of multiple stones was also evaluated; while we observed some association, it was statistically significant only in univariate analyses. In line with our findings, Mustafa et al. did not find a correlation between stone number and complications (26). Other reports indicate the number of stones is an independent predic- tor of low stone clearance, higher retreatment rates, and longer operative times, although they did not report an increase in complications (35, 36). Conversely, Perez et al. noted that having multiple stone locations was linked to higher postoperative complications (17). Additional factors potentially impacting URS complications may include the surgeon's experience, the use of auxiliary equipment, and different lithotripsy devices; however, these factors were not analyzed in our study due to the absence of laser lithotripters and the decision to avoid basket retrieval methods during most ureteroscopic pro- cedures. Study limitations This study has several notable limitations. The primary constraints include a low sample size and a retrospective design, which may affect the robustness of our findings. Relying on secondary data introduces variability in data Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 7 Emergency ureteroscopy quality, potentially due to inconsistencies in documenta- tion practices. The retrospective nature may also intro- duce selection and recall biases that could influence out- comes; the limited sample size restricts the ability to per- form comprehensive statistical analyses. Additionally, all procedures were conducted by experienced urologists, which might skew results toward more favorable out- comes. The presence of ureteral stents may impede the detection of minor stone fragments after removal, potentially con- tributing to increased postoperative complications. However, this study is the first systematic evaluation of complications associated with semirigid ureteroscopy in patients with ureteral stones at our center, yet its findings should be interpreted with caution. The single-center nature of this research limits the generalizability of the results to other populations and settings. Future research with larger sample sizes and multicenter designs is essen- tial to enhance understanding of the unique challenges and opportunities for treatment in resource-limited envi- ronments. CONCLUSIONS Emergency ureteroscopy with a semirigid ureteroscope has shown promising outcomes in managing ureteral stones. This approach is associated with minimal intraop- erative and postoperative complications, as well as satis- factory stone-free rates. Key factors in optimizing these outcomes include careful instrument selection, the surgi- cal team's expertise, and adherence to meticulous surgical techniques. Attention to these details is especially critical in complex cases involving larger stones or those posi- tioned in the proximal ureter, where procedural chal- lenges may increase. Prioritizing these aspects can signifi- cantly reduce the risks of adverse events during emer- gency ureteroscopy. REFERENCES 1. The global, regional, and national burden of urolithiasis in 204 countries and territories, 2000-2021: a systematic analysis for the Global Burden of Disease Study 2021. E Clinical Medicine. 2024; 78:102924. 2. Yoo MJ, Pelletier J, Koyfman A, et al. High risk and low prevalence diseases: Infected urolithiasis. Am J Emerg Med. 2024; 75:137-142. 3. De Coninck V, Keller EX, Somani B, et al. Complications of ureteroscopy: a complete overview. World J Urol. 2020; 38:2147- 2166. 4. Tanriverdi O, Silay MS, Kadihasanoglu M, et al. Revisiting the predictive factors for intra-operative complications of rigid ureteroscopy: a 15-year experience. Urol J. 2012; 9:457-64. 5. Wason SE, Monfared S, Ionson A, et al. Ureteroscopy. 2024 Apr 20. In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2025. 6. Kaczmarek K, Jankowska M, Kalembkiewicz J, et al. Assessment of the incidence and risk factors of postoperative urosepsis in patients undergoing ureteroscopic lithotripsy. Cent European J Urol. 2024; 77:122-128. 7. Fuganti PE, Pires S, Branco R, et al. Predictive factors for intra- operative complications in semirigid ureteroscopy: analysis of 1235 ballistic ureterolithotripsies. Urology. 2008; 72:770-4. 8. Farahat YA, Elbahnasy AE, Elashry OM. A randomized prospec- tive controlled study for assessment of different ureteral occlusion devices in prevention of stone migration during pneumatic lithotrip- sy. Urology. 2011; 77:30-5. d 9. Francesca F, Scattoni V, Nava L, et al. Failures and complications of transurethral ureteroscopy in 297 cases: conventional rigid instru- ments vs. small caliber semirigid ureteroscopes. Eur Urol. 1995; 28:112-5. 10. Tepeler A, Resorlu B, Sahin T, et al. Categorization of intraoper- ative ureteroscopy complications using modified Satava classification system. World J Urol. 2014; 32:131-6. 11. Mandal S, Goel A, Singh MK, et al. Clavien classification of semi- rigid ureteroscopy complications: a prospective study. Urology. 2012; 80:995-1001. 12. Molina WR, Kim FJ, Spendlove J, et al. The S.T.O.N.E. Score: a new assessment tool to predict stone free rates in ureteroscopy from pre-operative radiological features. Int Braz J Urol. 2014; 40:23-9. 13. Geavlete P, Georgescu D, Nita G, et al. Complications of 2735 retrograde semirigid ureteroscopy procedures: a single-center experi- ence. J Endourol. 2006; 20:179-85. 14. Zheng J, Wang Y, Chen B, et al. Risk factors for ureteroscopic lithotripsy: a case-control study and analysis of 385 cases of holmi- um laser ureterolithotripsy. Wideochir Inne Tech Maloinwazyjne. 2020; 15:185-191. 15. Gaizauskas A, Markevicius M, Gaizauskas S, et al. Possible com- plications of ureteroscopy in modern endourological era: two-point or "scabbard" avulsion. Case Rep Urol. 2014; 2014:308093. 16. Fathelbab TK, Abdelhamid AM, Anwar AZM, et al. Prevention of stone retropulsion during ureteroscopy: Limitations in resources invites revival of old techniques. Arab J Urol. 2020; 18:252-256. 17. Perez Castro E, Osther PJ, Jinga V, et al. Differences in uretero- scopic stone treatment and outcomes for distal, mid-, proximal, or multiple ureteral locations: the Clinical Research Office of the Endourological Society ureteroscopy global study. Eur Urol. 2014; 66:102-9. DECLARATIONS Ethical approval: Availability of data and material: All the data was included in this study. Competing interests: The author declares no potential con- flict of interest. Funding: None. Authors' contributions: All authors made a significant contri- bution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis, and inter- pretation, or all these areas; took part in drafting, revising, or crit- ically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work. Acknowledgments: None. Archivio Italiano di Urologia e Andrologia 2025; 97(2):13759 K. Al-Naggar, F. Ahmed, K. Al-Kohlany, I. Alnadhari 8 18. Alameddine M, Azab MM, Nassir AA. Semi-rigid ureteroscopy: Proximal versus distal ureteral stones. Urol Ann. 2016; 8:84-6. 19. Shrestha B, Koju R, Makaju Shrestha S, et al. Predictors of Stone Free Rate and Application of the Size, Topography, Obstruction, Number and Evaluation of Hounsfield Units (S.T.O.N.E) Scoring System in Predicting the Outcome in Patients Undergoing Semi-rigid Ureteroscopic Lithotripsy for Ureteric Calculi at a University Hospital of Nepal. Kathmandu Univ Med J (KUMJ). 2024; 22:31-35 20. Kim JW, Chae JY, Kim JW, et al. Computed tomography-based novel prediction model for the stone-free rate of ureteroscopic lithotripsy. Urolithiasis. 2014; 42:75-9. 21. Sirirak N, Sangkum P, Phengsalae Y, et al. External Validation of the S.T.O.N.E. Score in Predicting Stone-Free Status After Rigid Ureteroscopic Lithotripsy. Res Rep Urol. 2021; 13:147-154. 22. Mohammed S, Redi S, Berhe T, et al. Ureteroscopy Outcome and Its Determinants in a Resource-Limited Setting. Ethiop J Health Sci. 2022; 32:947-954. 23. El-Qadhi M. Outcome of ureteroscopy for the management of dis- tal ureteric calculi: 5-years’ experience. African Journal of Urology. 2015; 21:67-71. 24. Mursi K, Elsheemy MS, Morsi HA, et al. Semi-rigid ureteroscopy for ureteric and renal pelvic calculi: Predictive factors for complica- tions and success. Arab J Urol. 2013; 11:136-41. 25. Almusafer M, Jawad Al-Tawri A. Complications of ureteroscopic stone lithotripsy: A multicentre local study. Hamdan Med J. 2019; 12. 26. Mustafa M, Al Zabadi H, Mansour S, et al. Endoscopic Management of Upper and Lower Ureteric Stones Using Pneumatic Lithotripter: A Retrospective Medical Records Review. Res Rep Urol. 2023; 15:77-83. 27. Wagenius M, Rydberg M, Popiolek M, et al. Ureteroscopy: a pop- ulation based study of clinical complications and possible risk factors for stone surgery. Cent European J Urol. 2019; 72:285-295. 28. Bhojani N, Miller LE, Bhattacharyya S, et al. Risk Factors for Urosepsis After Ureteroscopy for Stone Disease: A Systematic Review with Meta-Analysis. J Endourol. 2021; 35:991-1000. 29. Daly KF, Mac Curtain BM, Collins E, et al. An analysis of the predictive factors for stone clearance at primary ureteroscopy. Ir J Med Sci. 2024; 193:2531-2535. 30. Waseda Y, Takazawa R, Kobayashi M, et al. Risk factors and predictive model for incidence of difficult ureter during retrograde ureteroscopic lithotripsy. Int J Urol. 2022; 29:542-546. 31. Bin X, Friedlander JI, Chuang KW, et al. Predictive factors for intraoperative balloon dilation in semirigid ureteroscopic lithotripsy. J Endourol. 2012; 26:988-91. 32. Osther PJS, Osther SS, Hesselholt MP, et al. Understanding intrarenal backflow: Intrarenal pressure during ureteroscopy and beyond. Asian J Urol. 2024; 11:139-142. 33. Kim JW, Lee YJ, Ha YS, et al. Secondary signs on preoperative CT as predictive factors for febrile urinary tract infection after ureteroscopic lithotripsy. BMC Urol. 2020; 20:131. 34. Elganainy E, Hameed DA, Elgammal M, et al. Experience with impacted upper ureteral stones; should we abandon using semirigid ureteroscopes and pneumatic lithoclast? Int Arch Med. 2009; 2:13. 35. Kurahashi T, Miyake H, Oka N, et al. Clinical outcome of ureteroscopic lithotripsy for 2,129 patients with ureteral stones. Urol Res. 2007; 35:149-53. 36. Pace KT, Kroczak T, Wijnstok NJ, et al. Same Session Bilateral Ureteroscopy for Multiple Stones: Results from the CROES URS Global Study. J Urol. 2017; 198:130-137. Correspondence Khalil Al-Naggar alnajjarkh1234@gmail.com ORCID: 0000-0001-9955-4537 Faisal Ahmed (Corresponding Author) fmaaa2006@yahoo.com ORCID: 0000-0001-7188-2715 Department of Urology, School of Medicine, Ibb University, Ibb, Yemen Khaled Al-Kohlany kalkohlani@gmail.com Department of Urology, College of Medicine, Sana'a University, Sana'a, Yemen Ibrahim Alnadhari ibrahimah1978@yahoo.com ORCID: 0000-0003-3371-2285 Urology Section, Department of Surgery, Al Wakra Hospital, Hamad Medical Corporation, Al Wakra, Qatar Department of Surgery, College of Medicine, Qatar University, Doha, Qatar