07 How we think Sacral Neuromodulation works

This is not an easy question to answer but over the last 20 years we have moved from thinking the stimulation “re-educates the pelvic floor” to much more complicated theories about how the stimulation re-informs parts of the brain and allows the bladder to be switched on again. We have used functional brain imaging to study the phenomenon and were able to show using both PET (position emission tomography) (Dasgupta, Critchley et al. 2005) and fMRI (functional magnetic resonance imaging) (Kavia, Dasgupta et al. 2010) that a centre in the midbrain which receives sensory signals from the bladder becomes activated in women with Fowler’s syndrome when the stimulator is switched on. This region is called the “periaqueduct grey” PAG and is now known to be very important in bladder control. Its re-activation seems to be linked to the patient’s report of a return of normal sensations from their bladder.

Regions of the brain where activation is restored by full bladder and SNM

Brain graphic

From (Panicker, DasGupta et al. 2010) see article below.

  • Click here to view in PDF format (741 kb) Chapter 19 from Pelvic Organ Dysfunction in Neurological Disease: Clinical Management and Rehabilitation, ed. Clare J. Fowler, Jalesh N. Panicker & Anton Emmanuel. Published by Cambridge University Press. copyright Cambridge University Press 2010).