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Systematic review analyzes renal hematoma risks following ureteroscopy and retrograde intrarenal surgery procedures in large patient cohorts

Systematic review analyzes renal hematoma risks following ureteroscopy and retrograde intrarenal…
Photo by Abdulai Sayni / Unsplash
Key Takeaway
Fever predicts unsuccessful conservative management of renal hematoma, while stone size and operative time increase risk.

This systematic review synthesizes data from a massive cohort of 23,258 patients to evaluate the safety profile of ureteroscopy and retrograde intrarenal surgery. The primary focus remains on the incidence of subcapsular renal hematoma and perirenal hematoma, critical complications that can impact patient recovery. By aggregating results from diverse studies, the analysis provides a robust estimate of complication rates that individual trials often fail to capture alone. The findings offer essential insights for urologists managing patients undergoing these increasingly common minimally invasive procedures.

The pooled incidence of subcapsular renal hematoma and perirenal hematoma was determined to be 0.42%, representing 74 total cases within the analyzed population. When stratifying by specific surgical technique, the data indicates a slightly higher incidence rate of 0.8% following retrograde intrarenal surgery compared to 0.4% after standard ureteroscopy. While these differences exist, the overall safety profile remains favorable for both approaches. Clinicians must weigh these baseline risks against the clinical benefits of stone removal and decompression of obstructed systems.

Identifying modifiable risk factors is crucial for optimizing patient outcomes and preventing severe hemorrhagic events. The analysis highlights stone size, prolonged operative duration, pre-existing hydronephrosis, and elevated intrarenal pressure as significant contributors to increased hematoma risk. Larger stones often necessitate more extensive dissection and longer fluoroscopic times, thereby elevating the potential for vascular injury. Similarly, patients with significant hydronephrosis may possess more fragile renal parenchyma, making them more susceptible to bleeding complications during instrumentation.

Beyond baseline characteristics, intraoperative variables play a pivotal role in complication development. Longer operative times correlate directly with higher exposure to potential bleeding sources and increased physiological stress on the patient. Surgeons must strive for efficiency without compromising the completeness of stone clearance. Understanding these dynamics allows for better preoperative counseling and the development of tailored surgical plans that mitigate specific risks associated with complex cases.

The study also addresses the management of hematomas that develop post-operatively. Fever was identified as the strongest predictor for unsuccessful conservative management in a subset analysis of 54 patients. This finding suggests that systemic inflammatory responses or infection may complicate the natural resolution of hematomas. Recognizing fever early allows for prompt intervention, potentially preventing the need for more invasive procedures like angiographic embolization or surgical drainage.

Despite the robust nature of this meta-analysis, limitations exist regarding the generalizability of the findings. The authors emphasize the need for validation in multicenter prospective studies before widespread clinical implementation of any new prognostic tools. Current data relies on retrospective aggregations which may introduce selection bias or heterogeneity in reporting standards. Future research should aim to standardize outcome definitions and prospectively validate risk prediction models in diverse clinical settings.

The development of the first prognostic tool for individualized risk stratification represents a significant advancement in urologic practice. Such tools can help surgeons identify high-risk patients prior to the procedure, enabling enhanced monitoring and preparedness. By integrating clinical predictors like stone size and operative time into decision-making algorithms, healthcare providers can personalize care plans to minimize adverse events. This approach aligns with broader trends toward value-based care and patient safety initiatives.

In conclusion, this systematic review provides a foundational understanding of hematoma risks associated with ureteroscopy and retrograde intrarenal surgery. The identified risk factors and predictors offer actionable intelligence for improving surgical outcomes. While the overall incidence remains low, vigilance regarding specific high-risk scenarios is warranted. Continued research and prospective validation will further refine these insights, ultimately benefiting the large population of patients requiring kidney stone treatment.

Study Details

Study typeMeta analysis
Sample sizen = 23,258
EvidenceLevel 1
PublishedJun 2026
View Original Abstract ↓
INTRODUCTION: To determine the incidence, risk factors, and clinical predictors of subcapsular renal hematoma (SRH) and perirenal hematoma (PRH) after ureteroscopy (URS) and retrograde intrarenal surgery (RIRS) using a structured multilevel evidence synthesis (Rare Events Valuation through Evidence-based And Layered synthesis [REVEAL] framework). METHODS: A systematic review and multilevel analysis were conducted according to PRISMA and a registered protocol (PROSPERO CRD420251085350). Literature searches (2000-2025) identified studies reporting SRH/PRH after URS/RIRS. A three-step framework was applied: meta-analysis (MA) of incidence using generalized linear mixed-effects models; MA of risk factors from comparative studies; and individual patient data (IPD) synthesis from case series and reports, followed by prognostic model development and nomogram construction. RESULTS: Fifteen studies, including 23,258 patients and 74 hematomas, were included. The pooled incidence of SRH/PRH was 0.42% (95% confidence interval: 0.22-0.79%), with slightly higher rates after RIRS (0.8%) compared with URS (0.4%). Stone size, longer operative time, hydronephrosis, and elevated intrarenal pressure were associated with increased risk. IPD analysis of 54 patients identified fever as the strongest predictor of unsuccessful conservative management. A multivariable model incorporating age, fever, hematoma length, hemoglobin drop, and time to presentation achieved strong discrimination and was translated into a prognostic nomogram to estimate individualized risk. CONCLUSIONS: SRH and PRH are rare but clinically significant complications of URS and RIRS. Using the REVEAL framework, we integrated heterogeneous evidence, identified technical and clinical risk factors, and developed the first prognostic tool for individualized risk stratification. Validation in multicenter prospective studies is required before clinical implementation.
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