Enhancing Renal Stone Management: Tip-Flexible Ureteral Access Sheath in Cystine Stone Surgery

BACKGROUND Cystinuria is a rare cause of urolithiasis. The condition is often inherited and controlled medically. A large symptomatic stone is indicated for surgery, and complete stone clearance is recommended to reduce the risk of infection and stone recurrence. CASE REPORT A 24-year-old healthy man was incidentally discovered to have multiple bilateral renal stones during a routine health examination. Upon admission to the Urology Department, preoperative computed tomography (CT) identified a large right renal stone measuring 30×25 mm and smaller, clinically insignificant stones in the left kidney. The patient opted to undergo removal of the right stone only, as he was asymptomatic and chose not to have the left stones extracted. He underwent right disposable digital flexible ureteroscopic lithotripsy using a tip-flexible suctioning ureteral access sheath, achieving complete stone clearance. His postoperative recovery was uneventful. At 1-month follow-up, stone composition analysis revealed that the stones were composed of L-cystine, leading to a diagnosis of cystinuria, a condition the patient was previously unaware of. He was prescribed urine alkalizing agents as part of his management. At the 6-month follow-up, CT confirmed that the right kidney remained stone-free. However, the left renal stones had significantly grown despite the use of urine alkalizing agents. To date, the patient has declined further surgical interventions for the left renal stones. CONCLUSIONS Early minimally-invasive intervention for cystine stones, including asymptomatic ones, may be necessary, as achieving complete stone clearance can improve prognosis by preventing complications associated with the stones.