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Residual fragments after percutaneous nephrolithotomy: is it mandatory to treat them all?
Andrea Li Puma1, Federica Passarelli1, Elisa De Lorenzis1,2
1Department of Urology, IRCCS Fondazione Ca' Granda, Policlinico di Milano, Milan, Italy.
Abstract:
To investigate complication rates, stone growth and passage according to residual fragments (RFs) size in a cohort of patients treated with miniPCNL (mPCNL). We retrospectively analysed data from 572 patients who underwent mPCNL between 01/2018 and 11/2023. We identified 105 (19.4%) patients with RFs and at least 1-year follow up. Demographics and RFs passage, regrowth and complications were recorded by chart review and phone interviews. RFs were stratified into ≤ 5 mm; 6-9 mm and ≥ 10 mm groups. Descriptive statistics and logistic regression models were applied to test the association between RFs size and stone related events. Median number and diameter of RFs were 2 (1-3) and 8 (5-10) mm, respectively. RFs of ≤ 5 mm (Group 1), 6-9 mm (Group 2) and ≥ 10 mm (Group 3) were detected in 27 (25.7%), 47 (44.7%) and 31 (29.6%) cases, respectively, after mPCNL. Overall, 23 (21.9%), 20 (19%) and 9 (8.5%) patients had a stone related event [emergency room (ER) admission], stone growth and passage during follow up, respectively. Renal colic requiring ER admission were more frequent in Group 2 compared to the ≥ 10 and ≤ 5 mm one (36.1% vs. 9.6% vs. 11.1%, p = 0.01). Conversely, Group 1 showed higher rates of stone growth compared to the other groups (37.0% vs. 17.0% vs. 6.4%, p = 0.02). No difference in the rate of UTIs and stone passage was reported according to RFs size. Multivariable logistic regression analysis showed that RFs of 6-9 mm had higher risk of stone related events (OR 5.5, p = 0.04) compared to the other groups, even after adjusting for patients' BMI. Conversely, patients with RFs ≤ 5 mm had higher risk of stone growth (OR 9.6, p = 0.04), compared to the other RFs groups, after adjusting for patients' BMI. RFs after mPCNL have different impact on patient's clinical course, according to their size. Large RFs are less likely to grow or cause stone-related events. Conversely, RFs of medium size (6-9 mm) are associated with higher risk of ER admission and should be promptly treated. Small RFs can increase in size, but conservative management or delayed surgery may be considered, as they typically remain asymptomatic during follow-up.
Insights
Residual fragments (RFs) after mini percutaneous nephrolithotomy (mPCNL) impact outcomes differently based on size. Medium RFs (6-9 mm) increase emergency room visits, while small RFs (≤5 mm) are prone to growth but often remain asymptomatic.
Area of Science:
- Urology
- Nephrolithiasis Management
- Minimally Invasive Surgery
Background:
- Residual fragments (RFs) after mini percutaneous nephrolithotomy (mPCNL) can influence patient outcomes.
- Understanding the impact of RF size is crucial for optimizing post-procedure management and patient follow-up.
Purpose of the Study:
- To investigate complication rates, stone growth, and passage based on residual fragment (RF) size after miniPCNL (mPCNL).
- To determine the clinical significance of different RF sizes to guide treatment decisions.
Main Methods:
- Retrospective analysis of 572 patients undergoing mPCNL, identifying 105 with RFs and at least 1-year follow-up.
- RFs were stratified into ≤5 mm, 6-9 mm, and ≥10 mm groups.
- Statistical analysis, including logistic regression, was used to assess the association between RF size and stone-related events.
Main Results:
- Patients with 6-9 mm RFs had a higher risk of emergency room admission (36.1%) compared to other groups (p=0.01).
- Smaller RFs (≤5 mm) showed higher rates of stone growth (37.0%) (p=0.02).
- Multivariable analysis indicated a 5.5-fold increased risk of stone-related events for 6-9 mm RFs and a 9.6-fold increased risk of stone growth for ≤5 mm RFs.
Conclusions:
- Residual fragment size significantly impacts clinical outcomes after mPCNL.
- Medium-sized RFs (6-9 mm) require prompt treatment due to increased risk of emergency room visits.
- Small RFs (≤5 mm) may be managed conservatively or with delayed intervention, as they are less likely to cause immediate complications but can grow over time.
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