Objectives: To determine the most frequent urodynamic observations associated with bladder calculi, and to assess whether the presence of calculi alters these observations.
Patients and methods: Fifty patients with bladder stones were included in a prospective study in which two urodynamic tests were used, one at inclusion and another once the patient was stone- free after treatment by noninvasive methods (mainly extracorporeal shockwave lithotripsy).
Results: The results from the urodynamic evaluation with the stone in the bladder were: bladder outlet obstruction in 51%, detrusor overactivity in 68%, detrusor under-activity in 10%, and a normal study in 18%. There were no significant differences between the urodynamic study before or after treatment in maximum flow rate and postvoid residual volume, detrusor overactivity and detrusor pressure at maximum flow.
Conclusions: Conversely to what has been accepted for years, bladder calculi are not always associated with bladder outlet obstruction and the urodynamic results are not influenced by the presence of bladder stones during the urodynamic testing.