Computerized assessment of detrusor instability in patients treated with sacral neuromodulation

Purpose: We previously described an automatic procedure for diagnosing and grading detrusor instability using a cystometric study. In our current stud y we applied a modi tied version of the program in patients with urge incon tinence treated with sacral neuromodulation to test its capacity to detect changes after therapeutic intervention and understand the mode of action of neuromodulation. Materials and Methods: We analyzed cystometric studies before and after neu romodulation in 26 consecutive patients, including 22 women and 4 men, and evaluated parameter changes. We also assessed the relationship of instabili ty parameters at baseline with symptomatic results, which were derived from voiding-incontinence diaries, in female patients to identify urodynamic pr ognosticators of success. Results: The automatic procedure correctly diagnosed stability and instabil ity in our patients in 51 of the 52 measurements considered. Neuromodulatio n had an average suppressive effect on the amplitude of unstable contractio ns. At baseline the amplitude of the maximum unstable contraction and mean active pressure during unstable episodes were significantly less in the 7 w omen who achieved stability than in the 15 who did not. However, no urodyna mic parameters were identified that predicted the symptomatic outcome of tr eatment. Conclusions: Our algorithm accurately diagnoses and grades detrusor instabi lity, and provides parameters with predictive value in regard to the probab ility that a bladder may or may not become stable with neuromodulation. How ever, the symptomatic result of this treatment option seems to depend on no ncystometric factors.