Outcomes in a large series of minipercs: analysis of consecutive 318 patients

The purpose of this study is to evaluate the outcomes of miniperc at our center.

This is a retrospective review of consecutive 318 minipercs done in a single tertiary urological center. The Miniperc system used was either Wolf (Richard Wolf) 14F with 20F Amplaz sheath or Storz (Karl Storz) nephroscope 12F with 15/18F sheath or 16.5/19.5F sheath. Data about the demography of patients, comorbidities, stone size, number and size of the tract, size of nephroscope, energy source used, total operative time, exit strategy, hospital stay, clearance of stones, total analgesic requirement, visual analogue pain score at 6 and 24 hours, hemoglobin drop and complications were analyzed by the chi-square test and analysis of variance test.

The average age of patients, stone size, operative time, hemoglobin drop and hospital stay were 41.9±17.0 years, 15.26±6.35 mm, 60±19 minutes,1.0±0.6 g/dL and 2.8±1 day, respectively. Complete clearance rate was 98.7%. Fourteen (4.4%) patients had Clavien-Dindo level 1 complications and 1 (0.31%) patient had Clavien-Dindo level 2 complications. The size of the stone treated by miniperc did not affect the hemoglobin drop (p-value=0.26) or hospital stay (p-value=0.924). There is no significant increase in hemoglobin drop (p-value=0.064) or hospital stay (p-value=0.627) with increasing number of miniperc tracts. An increase in operative time is associated with the increase in hemoglobin drop (p-value=0.041). Different energy sources did not significantly affect the operative time (p-value=0.184). Placement of only ureteral catheter is associated with less analgesic requirement (p-value=0.000).

Miniperc is a safe alternative to standard percutaneous nephrolithotomy. In carefully selected patients, the best exit strategy would be a tubeless procedure with ureteral catheter drainage.