Predicting Outcome Of Mini Percutaneous Nephrolithotomy Using STONE Nephrolithometry Score – A Single Centre Experience

Objective: To predict stone free rate and complication rate following mini-percutaneous nephrolithotomy (m-PCNL) using STONE nephrolithometry score. Methods: : This was a prospective observational study conducted in Department of Surgery, Urology Unit, Patan Hospital. All the patients undergoing m-PCNL were included. The cases were conducted in prone position, single tract less than 18 french was made and pneumatic lithotripsy was done. Stone free rates were assessed with plain X-ray kidney, ureter and bladder (X-ray KUB) at first post-operative day or at 15 days follow up. Complication within 30 days were graded using modified Clavien grading. Results: : Total of 106 patients were included in the final analysis. The overall stone free rate was 83%. Among the individual variables, only staghorn calculus was associated with residual stone (p = 0.007). Patients who were rendered stone free had statistically significant lower STONE score than those with residual stone (p <0.001). The complication rate was 23%, majority were Clavien grade I complications. Higher STONE score had greater risk of having complications but was not statistically significant (p = 0.11). Conclusion: STONE nephrolithometry score can predict stone complexity pre-operatively and subsequent stone free status and thus helps in pre-operative surgical planning and counseling for possible outcomes following m-PCNL.