Page 110 - Bladder Dysfunction in the Context of the Bladder-Brain Connection - Ilse Groenendijk.pdf
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Chapter 5
 Figure 2. Urodynamic parameters of the voiding phase of UDS B, UDS 1 and UDS 2.
DISCUSSION
To our best knowledge, this is the first study that suggests that sacral neuromodula- tion has no significant acute effect on standard UDS parameters in patients with OAB in whom SNM is eventually an effective treatment. This accounts for both the filling phase and the voiding phase. The figures show that besides the median change of the param- eters, the individual changes are also limited. These results are complementary to results of previous studies. Significant changes in UDS parameters were demonstrated after six months of SNM in patients with DO for both the filling and the voiding phase; the blad- der volume at first sensation increased, the bladder capacity increased, the maximum detrusor pressure during the filling phase decreased and the Qmax increased.22-24
The working mechanism of SNM is still being investigated, but at present, it is be- lieved that SNM activates afferent pathways modulating several brain areas which in turn regulate bladder control. Differences between acute and chronic SNM in regional cerebral blood flow (rCBF) have been demonstrated using PET.7 When acute SNM is ap- plied, brain areas predominantly involved in sensorimotor control, showed an increase in rCBF.7 Moreover, during acute SNM, Blok et al. described a change of rCBF in the insula. These authors argued that this might cause activation of the sympathetic system, which, in turn, results in an increase in the bladder capacity.7 The bladder capacity was not measured during this PET study. The current study did not demonstrate an increase in bladder capacity after acute SNM. In contrast to us, the study of Opisso et al. did show such an increase. They used subject-controlled dorsal genital nerve stimulation (DGN) in patients with neurogenic bladders due to partial spinal cord injury, multiple sclerosis or traumatic brain injury.27 Subjects could turn on the stimulator as soon as they felt urgency during bladder filling. However, the underlying mechanisms of bladder dys- function in neurogenic and idiopathic patients are not comparable.28 In the present study only patients with idiopathic OAB were included.





























































































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