Prospective Multicenter Evaluation of Pain Before and After Removal of Nonobstructing Renal Calculi: A CoRE Initiative.

ABSTRACT

PURPOSE: Flank pain associated with stone disease is typically caused by a stone that obstructs urine flow. However, it is plausible that nonobstructing kidney stones may still cause pain. We performed a multicenter, observational trial to evaluate whether treatment of small nonobstructing calyceal stones improves pain and kidney stone-specific health-related quality of life. MATERIALS AND METHODS: Patients aged 18 years or older with nonobstructing renal stone(s) up to 10 mm in longest diameter and moderate to severe pain were recruited. All participants completed 3 questionnaires the Brief Pain Inventory (BPI), the Patient-Reported Outcomes Measurement Information System pain interference form 6a, and the Wisconsin Stone Quality of Life questionnaire. Thereafter, all participants underwent ureteroscopy for renal stone treatment. All 3 questionnaires were repeated at 2, 6 to 8, and at 12 weeks postprocedure. The primary outcomes were change in preoperative to 12-week postoperative mean BPI score and worst BPI pain score. RESULTS: A total of 43 patients with nonobstructing kidney stones and associated flank pain were recruited. All stones were removed. Preoperatively, BPI scores for mean pain and worst pain were 5.5 and 7.2, respectively which decreased to 1.8 and 2.8 respectively at 12 weeks postoperatively. Wisconsin Stone Quality of Life questionnaire mean score increased from 70.4 to 115.3 at 12 weeks postoperatively. A total of 86% and 69% of patients had at least a 20% and 50% reduction in their mean pain scores, respectively. CONCLUSIONS: This study determined that patients benefit significantly from the removal of calyceal nonobstructing kidney stones for at least 12 weeks with a reduction in pain and an increase in quality of life. Therefore, surgical removal of these stones in this patient population should be offered as a treatment option.