The Long-Term Follow-Up of Patients with Cystine Stones: A Single-Center Experience for 13 Years.

INTRODUCTION

Cystine stone development is relatively uncommon among patients with urolithiasis, and most studies have reported only on small sample sizes and short follow-up periods. We evaluated clinical courses and treatment outcomes of patients with cystine stones with long-term follow-up at our center.

METHODS

We retrospectively analyzed 22 patients diagnosed with cystine stones between January 1989 and May 2019.

RESULTS

The median follow-up was 160 (range 6-340) months, and the median patient age at diagnosis was 46 (range 12-82) years. All patients underwent surgical interventions at the first visit (4 extracorporeal shockwave lithotripsy, 5 ureteroscopy, and 13 percutaneous nephrolithotripsy). The median number of stone events and surgical interventions per year was 0.45 (range 0-2.6) and 0.19 (range 0-1.3) after initial surgical intervention. The median time to stone events and surgical intervention was 2 years and 3.25 years, respectively. There was a significant difference in time to stone events and second surgical intervention when patients were divided at 50 years of age at diagnosis ( = 0.02, 0.04, respectively).

CONCLUSIONS

Only age at a diagnosis under 50 was significantly associated with recurrent stone events and intervention. Adequate follow-up and treatment are needed to manage patients with cystine stones safely.