Normal voiding is associated with a complex of reflex physiological events involving the somatic and autonomic nervous systems. Thus, detrusor contraction is accompanied by relaxation of the external urinary and rectal sphincters which ordinarily are in a state of tonic contraction. It is also accompanied by a slight rise in blood pressure and pulse rate. Neurogenic disorders, such as those produced by transverse myelopathy, result in changes in timing and intensity of these events.
Single methods of examination or testing such as cystoscopy, cystometry, sphincterometry, urethrography, electromyography of the bladder wall, electromyography of striate-muscle sphincters, flowmetry, and cineradiography, when used alone, are not adequate to demonstrate the physiological or pathophysiological events in an integrated and dynamic fashion.
A method, adaptable to clinical use, of simultaneous recording of intracystic pressure, indirect monitoring of the activity of the external urinary sphincter from the rectal sphincter, pulse rate, and blood pressure throughout bladder
Abramson AS, Roussan MS, D'Oronzio G. Method for Evaluating Function of the Neurogenic Bladder. JAMA. 1966;195(7):554-558. doi:10.1001/jama.1966.03100070098027