Extracorporeal Shock Wave Lithotripsy in Pediatric Patients Using a Late Generation Portable Lithotriptor: Experience at Children's Hospital Boston

Purpose: Kidney stones in children are increasing in incidence. The continued evolution of stone treatment modalities, including shock wave lithotripsy, makes the assessment of continuous outcomes essential. We describe contemporary shock wave lithotripsy outcomes in pediatric patients. Materials and Methods: A medical record review was performed of all patients younger than 20 years who underwent shock wave lithotripsy in 1998 to 2007. Patients were treated using a Dornier Compact Delta® lithotriptor with ultrasound and fluoroscopic imaging. Subjects were defined as stone-free if imaging within 12 months showed no evidence of stones with no additional treatment. Patient and treatment factors associated with successful outcomes were analyzed. Results: In 101 children a total of 114 treatment sequences were performed at a total of 150 shock wave lithotripsy sessions. Mean patient age was 10.5 years and 53% of the patients were girls. Mean stone diameter was 8 mm. Treatment was done for a solitary stone in 76% of cases, for 2 stones in 17% and for 3 or more in 7% with a mean shock count of 2,247. One, 2 and 3 or more treatment sessions were done in 78%, 16% and 6% of patients, respectively. The overall stone-free rate was 58.6%. However, the stone-free rate was only 12.5% after treatment sequences in 20 children with a history of anatomical urological conditions or surgery, while the stone-free rate in children without urological conditions was 67% (p <0.0001). Another factor associated with a decreased stone-free rate was stone size greater than 10 mm (25% vs 63%, p = 0.01). Complications included requiring acute reevaluation or treatment after 7% of shock wave lithotripsy sessions and 3.4% of patients required readmission. Conclusions: Extracorporeal shock wave lithotripsy is effective in many children with urolithiasis and it is well tolerated. However, in some children, particularly those with a history of urological surgery or congenital genitourinary conditions, success rates are low. These children may be best treated with other modalities.