Page 44 - Bladder Dysfunction in the Context of the Bladder-Brain Connection - Ilse Groenendijk.pdf

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Chapter 2
PFMC can be studied during different bladder states (empty vs full), sometimes used to interrupt micturition or suppress the urge to void. In the PFMC ALE, 4 studies investigated PFMC with a full bladder.10,19,22,23 Among those, Zhang et al. compared activation between PFMC with empty vs full bladder and demonstrated differences in SMA, basal ganglia and cerebellum. This might be of great interest towards the clinical applicability of fMRI in patient populations. To better understand the influence of bladder status on pelvic floor control, further studies comparing results at different bladder states are necessary.
Although the current meta-analysis did not specifically focus on sex related differences, data of both men and women were included. Tables 2 and 3 demonstrate that only two studies (1 PFMC and 1 micturition) in this review studied both men and women.4,7 The amount of data in the current systematic review was not sufficient to repeat the ALE analysis separately for men and women to study differences. The studies that included both men and women did compare the results between men and women. Moreover, the study of Seseke et al. focused specifically on this topic in relation to micturition comparing their male results with previous female results.22 In PFMC, no sex related differences were found,7 however, in another study about external anal sphincter con- traction, greater activity was found in men.40 Various arguments for this difference are described, like a more forceful contraction in men, the obvious anatomical differences between the genitourinary system or a general interhemispheric asymmetry of the hu- man motor cortex related to sexes.7,40,41 In micturition, stronger task related activity in the right thalamus and other right-hemispherical regions was found in women compared to men.4 Still, results on this topic are scarce and very heterogeneous. Other studies specu- late that women have a stronger brain activity during visceral stimulation than men.42,43
Clinical implications & reliability
Since our knowledge about the physiology of the innervation of the LUT has grown, lately more research is focusing on the results of neuroimaging in patients with LUT disorders, like chronic pelvic pain syndrome,21 stress urinary incontinence (SUI),28 urge urinary incontinence44,45 or multiple sclerosis (MS).15,46 Khavari et al.,46 studied differences in activation after onabotulinumA injections in patients with UUI and MS compared to healthy controls. It was demonstrated that during full urge, patients with UUI and MS show more deactivations compared to healthy controls in cortical and subcortical structures. After onabotulinumA injections, the brain responses were more in agree- ment with those of healthy controls. Furthermore, a study of Griffiths et al.45 clearly demonstrated an increased activation in patients with full bladder and UUI compared to healthy controls, particularly in the cingulate gyrus, SMA and prefrontal cortex. What these studies suggest, is that when patients react to therapy, activation patterns had more similarities with those of healthy controls, which is a very usable finding in future implication of fMRI.10,15,28,45-47 In the current ALE analysis, two studies were included with