Prevention of complications in endourological management of stones: What are the basic measures needed before, during, and after interventions?

Objective: This narrative review aims to describe measures to minimise the risk of complications during percutaneous nephrolithotomy (PCNL), ureteroscopy, and retrograde intrarenal surgery. Methods: A literature search was conducted from the PubMed/PMC database for papers published within the last 10 years (January 2012 to December 2022). Search terms included "ureteroscopy", "retrograde intrarenal surgery", "PCNL", "percutaneous nephrolithotomy", "complications", "sepsis", "infection", "bleed", "haemorrhage", and "hemorrhage". Key papers were identified and included meta-analyses, systematic reviews, guidelines, and primary research. The references of these papers were searched to identify any further relevant papers not included above. Results: The evidence is assimilated with the opinions of the authors to provide recommendations. Best practice pathways for patient care in the pre-operative, intra-operative, and post-operative periods are described, including the identification and management of residual stones. Key complications (sepsis and stent issues) that are relevant for any endourological procedure are then be discussed. Operation-specific considerations are then explored. Key measures for PCNL include optimising access to minimise the chance of bleeding or visceral injury. The role of endoscopic combined intrarenal surgery in this regard is discussed. Key measures for ureteroscopy and retrograde intrarenal surgery include planning and technique to minimise the risk of ureteric injury. The role of anaesthetic assessment is discussed. The importance of specific comorbidities on each step of the pathway is highlighted as examples. Conclusion: This review demonstrates that the principles of meticulous planning, interdisciplinary teamworking, and good operative technique can minimise the risk of complications in endourology.

Can Artificial Intelligence Accurately Detect Urinary Stones? A Systematic Review.

Objectives: To perform a systematic review on artificial intelligence (AI) performances to detect urinary stones. Methods: A PROSPERO-registered (CRD473152) systematic search of Scopus, Web of Science, Embase, and PubMed databases was performed to identify original research articles pertaining to AI stone detection or measurement, using search terms ("automatic" OR "machine learning" OR "convolutional neural network" OR "artificial intelligence" OR "detection" AND "stone volume"). Risk-of-bias (RoB) assessment was performed according to the Cochrane RoB tool, the Joanna Briggs Institute Checklist for nonrandomized studies, and the Checklist for Artificial Intelligence in Medical Imaging (CLAIM). Results: Twelve studies were selected for the final review, including three multicenter and nine single-center retrospective studies. Eleven studies completed at least 50% of the CLAIM checkpoints and only one presented a high RoB. All included studies aimed to detect kidney (5/12, 42%), ureter (2/12, 16%), or urinary (5/12, 42%) stones on noncontrast computed tomography (NCCT), but 42% intended to automate measurement. Stone distinction from vascular calcification interested two studies. All studies used AI machine learning network training and internal validation, but a single one provided an external validation. Trained networks achieved stone detection, with sensitivity, specificity, and accuracy rates ranging from 58.7% to 100%, 68.5% to 100%, and 63% to 99.95%, respectively. Detection Dice score ranged from 83% to 97%. A high correlation between manual and automated stone volume (r = 0.95) was noted. Differentiate distal ureteral stones and phleboliths seemed feasible. Conclusions: AI processes can achieve automated urinary stone detection from NCCT. Further studies should provide urinary stone detection coupled with phlebolith distinction and an external validation, and include anatomical abnormalities and urologic foreign bodies (ureteral stent and nephrostomy tubes) cases.

Long-term Outcomes of Minimally Invasive Rendezvous Procedures to Treat Complex Ureteric Strictures and Injuries.

Background: Complex ureteric strictures and injuries occurring during major abdominal and pelvic operations may cause significant morbidity and distress to patients. A rendezvous procedure is an endoscopic technique used in case of such injuries. Objective: To evaluate perioperative and long-term outcomes of rendezvous procedures to treat complex ureteric strictures and injuries. Design setting and participants: We retrospectively reviewed patients undergoing a rendezvous procedure for ureteric discontinuity including strictures and injuries, treated between 2003 and 2017 at our Institution and completing at least 12 mo of follow-up. We divided patients into two groups: early postsurgical obstruction, leakage, or detachment (group A) and late strictures (oncological/postsurgical; group B). Outcome measurements and statistical analysis: If appropriate, we performed a retrograde study ± rigid ureteroscopy to assess the stricture 3 mo after the rendezvous procedure, followed by a MAG3 renogram at 6 wk, 6 mo, and 12 mo, and annually thereafter for 5 yr. Results and limitations: Forty-three patients underwent a rendezvous procedure, 17 in group A (median age 50 yr, range 30-78) and 26 in group B (median age 60 yr, range: 28-83). Ureteric strictures and ureteric discontinuities were stented successfully in 15 out of 17 patients in group A (88.2%) and 22 out of 26 patients (84.6%) in group B. For both groups, the median follow-up was 6 yr. In group A, of 17 patients, 11 (64.7%) were stent free with no further interventions, two (11.7%) had a subsequent Memokath stent insertion (38%), and two (11.7%) required reconstruction. Of 26 patients in group B, eight (30.7%) required no further interventions and were stent free, ten (38.4%) were maintained with long-term stenting, and one was managed with a Memokath stent (3.8%). Of the 26 patients, only three (11.5%) required major reconstruction, while four patients with malignancy (15%) died during follow-up. Conclusions: With a combined antegrade and retrograde approach, the majority of complex ureteric strictures/injuries can be bridged and stented with an overall immediate technical success rate of above 80%, avoiding major surgery in unfavourable circumstances and allowing time for stabilisation and recovery of the patient. Additionally, in case of technical success, further interventions may be unnecessary in up to 64% of patients with acute injury and about 31% of patients with late stricture. Patient summary: The majority of complex ureteric strictures and injuries can be resolved using a rendezvous approach, avoiding major surgery in unfavourable circumstances. Moreover, this approach can help avoid further interventions in 64% of such patients.

14F Super-Mini Percutaneous Cystolitholapaxy: A Novel Technique in the Treatment of Bladder Stones.

Introduction: This single-center experience describes the indications, novel technique, and outcomes of performing 14F super-mini percutaneous cystolitholapaxy (14F-SMPCCL). Materials and Methods: Cases between 2019 and 2022 were retrospectively identified with surgical outcomes recorded. Using percutaneous access to the bladder, an endoscope was inserted through the ClearPetra 14F super-mini sheath and laser lithotripsy completed with stone fragments suctioned out. Results: Sixteen cases were included in the study and all patients were adults. Average conglomerate stone size was 28.1 mm (range = 10-50 mm). Average operative time was 60.0 minutes (range = 23-110 minutes). Visual stone-free rate was 91.7%, radiologic stone-free rate was 81.3%, and average postoperative length of stay was 1 day. One patient developed urosepsis postoperatively and there were no other complications. Conclusion: The novel technique of 14F-SMPCCL is safe and feasible for treating large burdens of bladder stones with a conglomerate size of ∼2.5 to 5 cm. Active suction allows for efficient removal of stone fragments.

Does relative renal function improve after intervention for chronic ureteric obstruction?

INTRODUCTION: Unilateral renal function often deteriorates with chronic ureteric obstruction. Our objectives were to determine the change in relative renal function (RRF) by MAG3 renography after intervention for ureteric obstruction, and to identify clinical/epidemiological factors which influence long-term outcomes. MATERIAL AND METHODS: We identified 228 patients from 2006 to 2017 who underwent MAG3 renography before and after intervention for unilateral ureteric obstruction. Patients were grouped into categories preoperatively - with normal RRF (43-57%) through mild (29-42%), moderate (15-28%) and severe (<15%) impairment of RRF. Patient demographics, types of obstructive uropathy and intervention employed were analysed. Each group was assessed for the absolute change in RRF and change in RRF category postoperatively. RESULTS: The mean patient age was 50.4 years (SD 16.7), and 62.3% were female. Overall, the mean pre- and post-intervention RRF of the obstructed kidney did not differ significantly (32.30% vs. 32.20%, P = 0.835). Most patients remained in their preoperative RRF group: 85.9% of normal, 67.4% of mild, 64.4% of moderate and 73.3% of patients with severe RRF impairment did not change category.Patients with mildly impaired preoperative RRF showed a significant worsening postoperatively (36.37% vs. 34.58%, P = 0.024). The other three groups showed no significant change in RRF following intervention.Multivariate logistic regression analysis showed no statistically significant association between type of intervention, age, gender or diagnosis and improvement in postoperative RRF category. CONCLUSIONS: Our results show that RRF does not improve significantly after intervention for ureteric obstruction. The aim should therefore be to maintain existing renal function and relieve symptoms.

Retained Urethral Catheter in the Ureter Following Misplaced Insertion in a Postpartum Female.

Background: Urethral catheterization is a common procedure, with a low complication rate. Aberrant catheterization into a ureter is a rare complication. We present a case of an aberrant urethral catheterization into the right ureter in a postpartum female. Case Presentation: An 18-year-old primigravida female presented with loin pain and catheter bypassing after a postpartum urethral catheterization. Examination under anesthesia and cystoscopy revealed the catheter leading into the right ureter, which was confirmed by subsequent CT urogram. Multiple attempts to remove the catheter failed. A rigid ureteroscopy was performed, revealing "kinking" of the catheter just distal to the balloon, as a result of an asymmetrical inflated balloon. A laser fiber inserted through the ureteroscope punctured the balloon, allowing balloon deflation and catheter removal under screening. A relook ureteroscopy 8 weeks later confirmed a healed ureter. Conclusion: Asymmetric catheter balloon inflation causes kinking of a catheter and occlusion of the balloon port that will prohibit balloon deflation. During rigid ureteroscopy, a laser fiber can be used to puncture the catheter balloon, allowing balloon deflation and catheter removal.