Optimal Shock Wave Frequency and Energy, Important Factors for Renal Stone Fragmentation in ESWL: A Prospective Randomized Trial

Abstract

Background: Kidney stones are crystalline structures with high prevalence rate across the globe. Different treatment method are used to treat renal stones among which extracorporeal shock wave lithotripsy (ESWL) shows promising results for stone free rate among non-invasive treatment modalities. Different factors govern effectiveness of lithotripsy among which shock wave frequency and energy had always been in debate as they have direct effect on responsiveness of ESWL. Objective: Comparison of different energy and shock wave frequency levels in terms of effectiveness in stone fragmentation. Study Design: Prospective randomized study. Settings: Department of Urology, DHQ Hospital/Faisalabad Medical University, Faisalabad Pakistan. Duration: April 2018 to September 2020 (2.5 Years). Methods: 120 patients enrolled using non probable consecutive sampling according to inclusion and exclusion criteria. Patients subjected to four sessions of ESWL using electromagnetic lithotripter and stones observed for fragmentation. Patients divided into four groups i.e. A, B, C and D depending upon frequency and energy of shock waves applied.(Group-A: Frequency 60 shocks/min Energy 50)(Group B: Frequency 90 shocks/min Energy 50)(Group C: Frequency 60 shocks/min Energy 65)( Group D: Frequency 90 shocks/min Energy 65). Each group further divided into subgroups 1 and 2 according to age as subgroup I patients having age 15-35 years and subgroup II having age 36-55 years. Statistical analysis done and P < 0.05 was taken as statistically significant. Results: 120 patients enrolled from age 15-55 years with mean age 37.191 + 11.09. Results showed that response of ESWL is statistically significant when frequency is low however both energy levels have equal response for effectiveness. Conclusion: We conclude that ESWL is an effective treatment method for renal stones when frequency of shock waves is less and combining it with low levels of energy shows with promising stone fragmentation rate with minimal side effects.