Comment on ?finite element models?a template for future urodynamics: Comparison of different computer models of the neural control system of the lower urinary tract,? Neurourol Urodynam (2000) 19:289-310

Non‐linearity in clinical practice

“…Another method is development of a finite element model (Petros 2001b). Using statistical methods and special objective assessment tools it may be possible to create, for each individual, a dynamic profile of function.…”

“…Using statistical methods and special objective assessment tools it may be possible to create, for each individual, a dynamic profile of function. Thus rather than relying on a specific result, it would be possible to give a dynamic range for each test or symptom, and these could be made instantly available as part of the software programme (Petros 2001b). This is ambitious, but necessary, given the non‐linearity of each medical system.…”

The integral theory physiologically guides mathematical models of bladder/bowel function and dysfunction

“…Urodynamic pressure changes were measured in a group of women who had low compliance. 8 These women registered a highly unstable pattern following handwashing, which seemed to block the corticoperipheral binary control system which maintained continence 8 (Figure 1). Modeling was carried out by applying known neurological functions to the Chaos Theory feedback equation X NEXT = cX(1 − X), where c is a variable representing the degree of inhibition of the micturition reflex, both peripheral and central and X = the fraction of maximum possible neurological impulses in the micturition circuit.…”

“…The equation was able to model every mode of the bladder: retention; normal; low compliance; bladder instability. 8,9 F I G U R E 2 The exponential nature of urine flow is related to urethral diameter, For a flow rate of 50 mL/s. (thick blue line), opening the urethral diameter from 3.5 to 4 mm reduces the head of pressure required by the detrusor to expel urine from the bladder from 172 to 100 cm water.…”

“…The IT's discoveries that pelvic muscles contract against ligaments to close urethra (continence), open urethra (urine evacuation), stretching bladder base to control premature activation of micturition reflex (urgency), allows measurement of its component parts, as inputs for the above functions. [3][4][5][6][7][8][9][10] Weak ligaments decrease the muscle forces acting on the urethra (Figure 1). Mathematical modeling can be assisted by ultrasound to measure inputs from ligament lengthening and urethral diameter during effort; by urodynamics to measure urethral pressure and flow inputs, with or without mechanical support of structures.…”