Extracorporeal Shock Wave Lithotripsy (ESWL) Outcome Based on CT Scan and Patient Parameters Using ESWL Score

Objective: To prospectively evaluate ESWL (extracorporeal shock wave lithotripsy) outcomes and validate ESWL Score. Study Design: An observational study. Place and Duration of Study: The Aga Khan University Hospital, from January 2021 to December 2021. Methodology: Patients with symptomatic, solitary, radio-opaque renal stone measuring <15 mm with normal renal functions were included in this study. Stone size <11mm, BMI <27 Kg/m², and stone density <900 Hounsfield units (HU) were all given 1 point each to give a total ESWL Score between 0-3 to each patient. Patients were evaluated after 4-weeks for the outcome i.e. stone clearance and complications. Results: A total of 146 patients were included in the study. Median values for age, stone size, BMI and stone density were 40 years, 8 mm, 27 Kg/m², and 774 HU respectively. Post ESWL, 99 (68%) patients were stone-free while 47 (32%) patients had residual stones. The stone clearance increased with the increasing score: 50% for ESWL score 0, 55.6% for ESWL score 1, 66.1% for ESWL score 2, and 85.7% for ESWL score 3 (p=0.01). The area under the curve (AUC) of ESWL score was 0.655 with 95 % CI (p=0.001). Conclusion: ESWL Score is a useful predictor of the success of ESWL. It can help decide the individualised and appropriate modality of treatment and assist with patient counselling.