Login to Access Video or Poster Abstract: MP62-15
Sources of Funding: none

Introduction

Extracorpreal Shock Wave Lithotripsy (ESWL) is an attractive non-invasive therapeutic modality for urolithiasis typically reserved for elective cases in a controlled setting. Proceeding directly to ESWL without pre-stenting in patients presenting to the emergency room with acute renal colic secondary to upper ureteric calculi can spare patients multiple anesthesia-requiring procedures. In this study, we aim to compare upper ureteric stone clearance with and without pre-stenting in patients undergoing ESWL within 48 hours of their initial presentation.

Methods

Between July 2012 and July 2015, 124 patients who had presented to emergency with renal colic secondary to upper ureteric calculi were recruited for this study. Criteria for exclusion included abnormally elevated renal parameters, signs of a concomitant infectious process (fever, leukocytosis, or a positive urine dipstick), pain poorly responding to analgesia, radiolucent stones, or stones smaller than 4-mm or larger than 15-mm in size. 72 patients had been randomly assigned to undergo ESWL directly without pre-stenting (Group A), while 52 patients were assigned for pre-stenting (Group B), with their data and outcomes prospectively collected. Mean patient BMI in both groups was 26.1 and 26.7 kg/m2 (p = 0.49), mean skin-to-stone distance was 11 and 10.1 cm (p = 0.03), mean stone size was 7.3 and 7.8 mm (p = 0.114), and mean stone density was 902 and 1078 Hounsfield units (p = 0.005) respectively.

Results

72 patients had undergone emergency ESWL directly without pre-stenting (Group A), while 52 patients had undergone pre-stenting before emergency ESWL (Group B). All 124 patients had their first session of ESWL done within 48 hours of their initial presentation. 8 patients were lost to follow up in Group A, while one patient was lost to follow up in Group B. Four patients' stones had migrated to the kidney with stenting and were excluded from the study. Stone clearance in both groups was 61% and 44% (p = 0.068) after one session, 91% vs 59% (p = <0.001) by the second session, and 95% and 73% (p = 0.001) by the third and last session. No patients in Group A crossed over to Group B or required stenting at any point.

Conclusions

Emergency ESWL for upper ureteric calculi offers excellent stone clearance outcomes for properly selected patients with an acute presentation of renal colic that has subsided. Proceeding directly for ESWL without pre-stenting was associated with significantly enhanced stone clearance while sparing the patient multiple invasive interventions and their potential morbidity.

Funding

none