Factors influencing bladder stone formation in patients with spinal cord injury.

OBJECTIVE: Bladder stones that form in patients with spinal cord injury (SCI) can cause significant morbidity. This study sought to analyze factors associated with bladder stone formation to determine which patients might be at increased risk to develop bladder stones.
METHODS: A review of 56 SCI patients treated for bladder calculi over a 10-year period at a single institution was performed. These patients were compared with a control population of general SCI patients known to be stone free. The factors compared were patient age, duration of injury, level of injury, completeness of injury, method of bladder management, and the presence of documented urinary tract infections with urease-producing organisms.
RESULTS: All patients with stones were male and had a median age of 58.5 years. The median level of injury was C6, the median time since injury was 21 years, 66% had complete injuries, 68% managed their bladders with indwelling catheters or suprapubic tubes, and 83% had a history of infections with urease-producing organisms. When compared with the control group, patients forming bladder stones were older (P = 0.03), were more likely to have indwelling catheters (P < 0.0001), had a history of infections with urease-producing organisms (P = 0.04), and had complete injuries (P = 0.018).
CONCLUSION: This information can be used to identify patients who have an increased risk of bladder stones and measures can be taken to reduce their incidence and morbidity.