REAL-TIME CHANGES IN BRAIN ACTIVITYDURING SACRAL NEUROMODULATION FOR OVERACTIVE BLADDER
J. PIZARRO-BERDICHEVSKY1,B. GILL 2, P. BHATTACHARYYA 3, S. E. JONES 3,H. B. GOLDMAN 2;
1Urology; UrogynecologyUnit; Division Obstetricia y Ginecologia, Cleveland Clinic; H. Dr.Sotero del Rio; Pontificia Univ. Catolica de Chile, Santiago, Chile,2Urology, Cleveland Clinic, Cleveland, OH, 3Radiology,Cleveland Clinic, Cleveland, OH.
Introduction: Sacralneuromodulation (SNM) is an effective third-line OAB therapyproviding high rates of treatment success and patient satisfaction.The precise mechanism of SNM action remains elusive. Multiple studiesof OAB with functional magnetic resonance imaging (fMRI) demonstrateincreased areas of activation associated with urinary symptoms andurge. Recently, brain activity on fMRI in women with OAB before andafter PFPT has been shown to differ between therapeutic successes andfailures. Normal 0 false false false As the mechanism of SNM remainsunknown, and altered brain activity in OAB has been described, thestudy presented herein tested the hypothesis that brain activity inwomen with OAB responding to SNM is impacted by therapy.
Objective:To use functional magnetic resonance imaging (fMRI) for identifyingchanges in brain activity during sacral neuromodulation (SNM) inwomen with overactive bladder (OAB) who responded to it astherapy
Methods: Women with non−neurogenic refractory OABwho responded to SNM, had a stable program for at least 3 months, andreceived no subsequent OAB treatment were recruited. Enrolledpatients completed pre−fMRI validated symptom and quality of lifeinstruments. Next, stimulus settings were recorded, devices switchedoff for a 5−day washout, and instruments repeated. Three fMRI scansbelow, at, and above stimulus sensory threshold were done. fMRI datawere 2−dimensional gradient echo−planar imaging blood−oxygenationlevel dependent contrast(EPI−BOLD) acquired over 5 stimulator−offand 4 stimulator-on cycles of 42 seconds each. Output images usesingle voxel p−value 0.05 with false positive error of 0.05(cluster−analysis determined).
Results: Of 13 patientsenrolled, 6 completed fMRI and had median age 52[36−64] years.Urinary bother and symptoms worsened with washout, and voiding diarydata supported this. An overall pattern of brain activation generallyprogressed with increasing stimulation amplitude, but activation ofthe right inferior frontal gyrus remained stable, while deactivationof the pons and periacqueductal gray matter only occurred withsub−sensory stimulation. Sensory stimulation activated the insulabut deactivated the medial and superior parietal lobes. Suprasensorystimulation activated multiple structures and the expected S3somatosensory region. All devices had normal impedances afterfMRI.
Conclusions: fMRI confirms SNM influences brainactivity in women with OAB who responded to therapy. These changesvary with stimulus intensity.