Impact of renal function on efficacy of extracorporeal shockwave lithotripsy

Adequate urine production and excretion may be important for clearance of stone fragments after extracorporeal shockwave lithotripsy (SWL). This study evaluated the impact of renal function, measured by preoperative serum creatinine concentration, on the efficacy of SWL.

From 1986 to 2001, 27,299 patients with urolithiasis were treated with Medstone STS lithotripters. Seven hundred ninety-eight of these patients (2.92%) had serum creatinine concentrations >or=2.0 mg/dL. Perioperative renal function (serum creatinine), treatment parameters, stone-free success rate (no residual fragments on plain film), and perioperative complications and procedures were recorded.

The stone-free rate for patients with serum creatinine values from 2.0 to 2.9 mg/dL (56.69%) was significantly less than that seen in patients with a creatinine concentration <2.0 mg/dL (66.20%). The retreatment rate and secondary-procedure rate were significantly higher in patients with higher serum creatinine values (9.62% and 8.92%, respectively) than in those with serum creatinine within the normal range (6.07% and 4.27%, respectively). There was no significant difference in the stone-free rate, re-treatment rate, and secondary-procedure rate of patients with serum creatinine >or=3.0 mg/dL in comparison with patients with values <2 mg/dL. Complication rates were higher for patients with serum creatinine values >4.0 mg/dL (10.91%) than for patients with creatinine <2.0 mg/dL (2.62%).

The efficacy of SWL is decreased in patients with serum creatinine concentrations of 2.0 to 2.9 mg/dL, and the complication rate is higher in patients with serum creatinine >4.0 mg/dL. Preoperative counseling may include a discussion of the impact of renal insufficiency on success and complication rates associated with SWL.