A 52-year-old woman with a history of recurrent calcium oxalate kidney stones presents with acute left flank pain and hematuria. Non-contrast CT KUB reveals a 15 mm stone in the left mid-ureter with moderate hydronephrosis. Serum creatinine is 1.8 mg/dL (baseline 1.0 mg/dL), and she is afebrile. Urine culture is pending. She has severe pain uncontrolled by NSAIDs and intravenous fluids. What is the most appropriate next step in management?