The impact of new technology in the treatment of cystine stones

Cystinuric patients frequently require stone removing procedures because of their high tendency to have recurrent urinary calculi. In the last 20 years the morbidity of stone treatment has been reduced by the introduction of endourologic procedures and shock wave lithotripsy (SWL), but cystine stones are not amenable to all minimally invasive procedures. The aim of our study was to assess the impact of new technology in the treatment of cystine stones. The records of patients observed at our institutions from 1978 to 2005 were reviewed. We retrospectively analysed the previous stone histories of all the patients who presented at our institutions for stone treatment who resulted to be cystinuric at our metabolic work up. Patients were divided in two groups according to the date of our first observation: group A comprised patients observed from 1978 to 1989 who mainly experienced traditional stone treatment and group B patients observed from 1990 to present who were preferentially treated with minimally invasive therapeutic modalities. A total of 48 cystinuric patients were observed (31 in group A and 17 in group B). The mean age (38 +/- 15 vs. 36 +/- 13 years), the age at stone onset (21 +/- 11 vs. 21 +/- 12) and the annual recurrence rate (1.34 +/- 2.38 vs. 1.16 +/- 1.11 stones/year/pt) were not significantly different in the two groups. The male/female ratio was 18/13 and 8/9, respectively, in group A and B. In group A 16 patients underwent open surgical treatment for a total of 29 procedures (0.93 for patient) and four of them had nephrectomy; in group B only eight underwent open surgery but other seven had percutaneous surgery (0.47 + 0.41 procedure/patient). In group B 37 SWL treatments were performed (2.17 for patient) whereas patients in group A underwent only four SWLs. Renal function was impaired in six patients (19%) in group A with a patient requiring haemodyalitic treatment and in one patient (6%) in group B. Compared to the traditional stone treatment, after 1990 fewer cystinuric patients required open surgery and none underwent nephrectomy or developed severe renal failure. Our results indicate that the actual care of patients with cystine stones should still be improved requiring a comprehensive approach in order to avoid inappropriate SWL treatments and more attention to early diagnosis and preventive measures.