Does altered myogenic activity contribute to OAB symptoms from detrusor overactivity? ICI-RS 2013.

AIMS: To highlight novel experimental approaches that test if the Myogenic Hypothesis remains viable as a contributor to the aetiology of detrusor overactivity. METHODS: To summarise the conclusions of a workshop held under the auspices of ICI-RS in 2013. RESULTS: Several theories may explain the pathology of detrusor overactivity and include a myogenic theory with fundamental changes to detrusor muscle excitation-contraction coupling. The isolated bladder displays micromotions that do not normally translate into significant changes of intravesical pressure. However, their amplitude and frequency are altered in animal models of bladder dysfunction. The origin of micromotions, if they generate significant changes of intravesical pressure and contribute to urinary tract sensations remain unanswered. Within the myocyte, changes to contractile protein phosphorylation through accessory proteins and cytoplasmic regulatory pathways occur in lower urinary tract pathologies associated with detrusor overactivity. Furthermore, myocytes isolated from overactive human bladders generate greater spontaneous activity, but a complete description of changes to ionic currents remains to be characterised. Finally, several growth factors, including mechano-growth factor, are released when bladder wall stress is increased, as with outflow obstruction. However the phenotype of the transformed detrusor myocytes remains to be measured. CONCLUSIONS: A number of lines of evidence suggest that the Myogenic Hypothesis remains viable as a contributor to detrusor overactivity.

Clinical examination and dynamic magnetic resonance imaging in vaginal vault prolapse.

OBJECTIVE: To estimate the role of dynamic magnetic resonance imaging (MRI) as a diagnostic tool in the evaluation of vaginal apex prolapse in women with previous hysterectomy. METHODS: Clinical examinations were performed on 51 women presenting with symptoms of prolapse. A preoperative dynamic MRI assessment was performed. The mid pubic line was the reference level used for prolapse grading. The parameters of analysis included 1). correlation by compartments of clinical and MRI grading of prolapse, 2). assessment of the accuracy of clinical examination of the middle compartment, and 3). identification of any additional information provided by MRI. All MRI films were analyzed and validated by the same two observers. RESULTS: Analysis of each compartment separately revealed poor correlation between clinical and MRI assessment. Of the 51 cases with clinical vault prolapse, 27 (52.9%) cases were clinically overdiagnosed, 3 (6%) were underdiagnosed, and there was agreement in 21 (41.1%) when compared with MRI findings. Postoperative follow-up of the 18 (85%) patients who underwent colposacropexy after intraoperative assessment revealed the presence of cystocele in 4 (26.6%) occasions and rectocele in 3 (20%), which had been detected on MRI but not confirmed intraoperatively. CONCLUSION: There is poor correlation between clinical and MRI findings when assessing vaginal apex prolapse. Magnetic resonance imaging allows the identification of other prolapsing compartments and may be a complementary diagnostic tool for the diagnosis of complex vaginal apex prolapse.