UP-83 Are post-operative nephrostomy tubes needed in the mini percutaneous nephrolithotomy era?
Thursday June 27, 2019 from

JO-LYNN S TAN, Australia

Urology Registrar

Department of Urology

St Vincent's Hospital Melbourne


Are post-operative nephrostomy tubes needed in the mini percutaneous nephrolithotomy era?

Jo-Lynn Tan1, Matthew Farag Dr3, Lih-Ming Wong Mr1,3, Damien Bolton Professor2,3, Daniel Lenaghan Mr1.

1Department of Urology, St Vincent's Hospital, Melbourne, Australia; 2Department of Urology, Austin Health, Melbourne, Australia; 3Department of Surgery, University of Melbourne, Melbourne, Australia

Introduction: Percutaneous nephrolithotomy PCNL, the standard procedure for large intrarenal calculi may be performed using a “mini” (mPCNL) or conventional (cPCNL) approach, differentiated by way of the access tract size (14-20Fr versus >24Fr). mPCNL gained momentum in clinical practice due to purported higher safety profiles but has longer operating times without superior stone clearance rates. Owing to small published study sizes and study heterogeneity, a lack of consensus on the superiority of one technique over the other remains. We hypothesised that perioperative outcomes between mPCNL and cPCNL are now comparable, with a lesser need for nephrostomy tubes. We aimed to compare and report on the perioperative and surgical outcomes of cPCNL versus mPCNL.

Methods: We retrospectively reviewed all cases of PCNL between January 2016 to July 2020, at two high-volume tertiary centres. Baseline data collected included age, BMI, previous stone surgery, stone size and location. Peri-operative (tract size, operation time, patient position), and post-operative (change in haemoglobin (Hb), renal function, hospital length of stay (LOS), rate of stone clearance) outcomes were studied. Mann–Whitney U-tests and Fisher’s exact t-tests were used to analyze continuous, and Pearson’s chi-square tests were used for categorical variables. Statistical significance was set at p<0.05.

Results: 95 patients were included in our analysis (n=76 mPCNL vs n=19 cPCNL). Baseline characteristics were similar between groups except for BMI, which was higher in the cPCNL group (mean kg/m2 31 vs 27, p=0.03). Pre-operative stone size and location were similar between groups. No significant differences were found for change in eGFR (mean 6.5 vs 6.1mL/min, p=0.95), change in Hb (mean 13.9 vs 18.2, p=0.18), transfusion rates (p=0.78), operation time (mean 212 vs 195min, p=0.48) or rate of stone clearance by tract size (p=0.41). Total stone clearance rate was greater with prone positioning (p= 0.001). Interestingly, nephrostomy tube insertion was associated with increased LOS (p=0.03), but did not correlate with stone or residual fragment size.

Conclusion: mPCNL demonstrates equivalent perioperative and functional outcomes to cPCNL. Furthermore, routine post-operative NT insertion after PCNL may not confer additional benefit and warrants further study.

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