Comparative evaluation of the efficacy and safety of antegrade minimally percutaneous nephrolithotomy and retrograde intrarenal surgery in the treatment of upper ureteral impacted stones: a retrospective cohort study.

Abstract

Objective: To compare the safety and efficacy of retrograde intrarenal surgery (RIRS) vs minimally invasive percutaneous nephrolithotomy (mPCNL) in the minimal invasive management of impacted upper ureteral stones along with the evaluation of predictive radiological parameters.

Patients and methods: A retrospective analysis was done in 124 patients, undergoing RIRS (n:61) and mPCNL (n:63) for the management of impacted upper ureteral stones. Both operative (success and complication rates, operative time, postoperative hospital stay) and radiological (ureteral wall thickness, UWT), stone volume (SV), and stone density (Hounsfield unit, HU) factors were all evaluated and recorded. Comparative evaluation of stone free status in both groups was done following 72 hours and 4-weeks after the procedures to calculate the primary stone-free as well as final stone clearance rates. Additionally, the outcomes of RIRS group were categorized based on the intraoperative findings (presence or absence of stone encasement by a polyp) and preoperative radiological parameters. All data were well analyzed for statistical significance. A significance level of p<0.05 was considered statistically significant.

Results: Baseline patient and stone related characteristics were similar in two groups. The success rates after a single session for RIRS and mPCNL were 73.77% and 93.65%, respectively (p=0.003), indicating a significantly higher success rate for mPCNL. However the final stone clearance rates were 96.72% and 100.00%, respectively (p=0.147), with no significant difference observed among the groups. The RIRS group demonstrated higher rate of need for auxiliary treatments (p<0.001), shorter hospital stay (p<0.001) and lower incidence of bleeding (p<0.001). Radiological evaluation showed no significant differences in stone volume, HU and UWT values between patients with and without residual stones after RIRS (Pstone volume = 0.151, PHU = 0.451, PUWT = 0.083). Similarly, no significant differences were observed with respect to these values also in mPCNL patients, (Pstone volume = 0.532, PHU = 0.455, PUWT = 0.658). However, a significant difference has been noted regarding the mean value of UWT between the stones surrounded by a polypoid alterations and the ones without such changes with values 5.23 ± 0.65 mm, to 4.10 ± 0.82 mm, respectively (p=0.001).

Conclusions: Our results demonstrated that antegrade mPCNL achieves faster stone clearance and a lower re-treatment rate without serious complications in impacted upper ureteric stones. However, RIRS could be a valuable and safe alternative with comparable success rates particularly in cases with contraindications to or unwillingness for mPCNL. Preoperative assessment of ureteral wall thickness (UWT) value may be a good predictor for the possible tissue changes in ureteral wall at stone site to guide the decision making of the most appropriate surgical approach.