Accuracy of predicting bladder stones based on catheter encrustation in individuals with spinal cord injury.

BACKGROUND

Bladder calculi are the second most common urological complication in those with spinal cord injury (SCI). Detection and removal of bladder stones are important to prevent possible complications.

OBJECTIVE

To determine the accuracy of bladder stone detection based on catheter encrustation in asymptomatic individuals with SCI.

DESIGN

Prospective cohort study.

METHODS

Cystoscopy findings in persons with SCI who were noted to have catheter encrustation at the time of catheter removal for their scheduled cystoscopy were used in this prospective study. Indwelling catheters were examined for encrustation at the time of removal as they were being prepared for cystoscopy. Cystoscopy was performed, and the presence or absence of bladder stones was noted.

MAIN OUTCOME MEASURES: Presence or absence of bladder stones detected with cystoscopy in those with precystoscopy catheter encrustation.

RESULTS

Forty-nine individuals with indwelling catheters were evaluated. Overall, 17/49 (35%) individuals in this study had bladder stones. Catheter encrustation was noted in 13 patients. Of these 13 patients, 11 also had bladder stones. In other words, a positive result for catheter encrustation had a positive result for bladder stones 85% of the time. Thirty-six individuals had no catheter encrustation. Of these, 6 (16%) were found to have bladder stones.

CONCLUSIONS

Encrustation of a catheter is highly predictive of the presence of bladder stones. This suggests that cystoscopy should be scheduled in a person undergoing a catheter change if catheter encrustation is noted.