Non-linearity - a dilemma and opportunity for clinical research in urogynecology


Pelviperineology 2015;34(4):0-0

The female pelvic floor contains the most complex interconnected nonlinear controlled system of muscles and ligaments in the body. The dilemma Much of the research in urogynecology today is reductionist, never ending classifications attempting to fit complex issues into simplistic reductionist boxes. Examples are the POPQ system, complex classifications of mesh complications, urodynamics used in place of urge symptoms, replacing symptoms with numbers, “scores”. Use of simple language is suggested to report results and application of Occam’s Razor to distinguish relevance of rival systems. The opportunity Complexity and Chaos are the key to understanding the variance inherent in pelvic floor function and are a rich direction for future research. The importance of ‘criticality’ in speedily changing the bladder phase from ‘closed’ to ‘open’ is described as are the non-linear mechanisms driving this system, an external striated muscle mechanism acting against suspensory ligaments, and the internal resistance to urine flow which, following the Law of Poiseuille, is inversely proportional to the 4th power of the change in urethral radius by this mechanism. The impossibility of pre-operatively determining the initial conditions as a guide to therapy is discussed and how this can be bypassed by repairing the ultimate cause of the dysfunction, damaged ligaments, with tensioned slings Repairing the ligaments works by reversing the non-linear cascade of events consequent upon inability of the musculoelastic control mechanisms to ‘grip’ on the loose ligaments. A simple research protocol for reversing these complex cascades is detailed by supporting various suspensory ligaments.