Clinical features determining the fate of a long-term, indwelling, forgotten double J stents.

We review our experiences with forgotten stents and investigate the potential factors determining the degree of encrustation. Our series consists of nine cases of forgotten stent that had remained indwelling for more than 1 year (mean 36.1 months). We describe and compare their various clinical parameters in terms of encrustation. In addition, we briefly summarize our management schemes. All patients showed few stent related irritative symptoms. Six cases showing minimal or no encrustation shared the common feature of urine hypotonicity. Cystoscopic pullout was possible in these cases. The remaining three cases showed moderate to severe encrustation around the stent which required multiple procedures. Pyuria was observed in all cases and two patients had a history of urolithiasis. Finally, all cases were rendered stent and stone free. The fate of forgotten stents was dependent on the amount of encrustation around the stent. In our study, lithogenic history and presence of pyuria were associated with moderate to severe encrustation. Interestingly, patients showing urine hypotonicity tended to have a minimal encrustation on their stents and the stents were easily removed. Therefore, in patients with an impaired renal concentrating ability and a poor medical condition, the duration of indwelling stents might be safely prolonged if the patient has no risk factor for encrustation. As patients with forgotten stents are less likely to complain of stent related symptoms, thorough education of patients is important to prevent stent related complications.