New research into the brain effects of intradetrusor injection of onabotulinumtoxinA (OnabotA [Botox]) could uncover alternate sensory pathways of this treatment modality.
Furthermore, increased understanding of bladder dysfunction at the level of the brain may lead to novel supraspinal modulation as a potential treatment modality for bladder dysfunction, researchers say.
OnabotA appears to increase the activity of brain regions involved in sensation and processing of urinary urgency in female patients with neurogenic overactive bladder (OAB), said Rose Khavari, MD, of Houston Methodist Hospital, Houston and Weill Cornell Medical College, New York.
"If we can better modulate the brain regions involved in bladder function, we may be able to use the same concept and help patients with any bladder storage or emptying problem," Dr. Khavari told Urology Times.She presented the study findings at the AUA annual meeting in San Francisco.
Previous research has extensively described onabotA’s effects on detrusor muscle activity (motor effects), but little is known about its sensory or supraspinal neural effects. Functional neuroimaging studies have suggested increased activity in the cingulated cortex, insula, and frontal cortex of women with OAB in response to bladder filling.
And previous studies have shown that therapies such as biofeedback, anticholinergic medications, and sacral neuromodulation can alter brain areas involved in bladder control.
So Dr. Khavari and her colleagues wanted to evaluate the effects of intradetrusor onabotA on brain activity in female multiple sclerosis (MS) patients with neurogenic overactive bladder.
They recruited 12 women diagnosed with stable MS for at least 3 months and neurogenic detrusor overactivity who were refractory to conservative and oral pharmacologic management. The women ranged in age from 38 to 71 years, with a mean age of 43.9 years. The authors excluded men from the study to avoid confounding the results with bladder outlet and prostate pathology.
The women underwent functional magnetic resonance imaging (fMRI) with simultaneous urodynamic studies prior to and 6 weeks following treatment with intradetrusor injection of onabotA.
During the filling phase, patients signaled strong urgency. The authors created average fMRI activation maps at strong urgency identifying areas of significant activation (p<.05).
Following intradetrusor injection of onabotA, they recorded a decrease in urge urinary incontinence (UUI) from 1.64 per day to 0.42 per day, along with improvements on validated questionnaires and assessments.
Next: What the authors found