Factors that influence the incidence of detrusor instability in women.

Detrusor instability was examined in 108 women with urinary incontinence. The presence of instability correlated with the symptoms of urge incontinence in 81 of 99 patients. The technique of the cystometrogram also proved important and minor variations significantly altered the incidence. Finally, there seems to be a significant correlation between reduced urethral closure as measured by the urethral pressure profile and instability, suggestive of a causal relationship. An understanding of the factors that affect the incidence of detrusor instability will help to place it in the right perspective in terms of its diagnostic value and pathogenesis.