Author Proof A Neurourology and Urodynamics 9999:1–2 (2010) LETTER TO THE EDITOR OAB Can Be Modulated by External Musculo-Elastic Forces The hypothesis, “that urgency is an all or none phenomenon” 1 is easily tested by the well-known practice of women “squeez- ing” (contracting their pelvic muscles upwards) to successfully control urge symptoms. Another method for controlling early morning urge is to press on the suprapubic area. These two examples demonstrate that urgency can be modulated. In some cases, urgency, and even urodynamic traces of OAB can be mod- ulated by digitally supporting the bladder base. 2 One issue not raised by the authors is that the sequence of events in OAB was demonstrated in 1993 3 to be identical to that ob served in a normal micturition: (1) sensation of urgency, (2) fall in prox- imal urethral pressure, (3) rise in detrusor pressure, (4) urine loss. This concept, OAB being a prematurely activated, but other- wise normal micturition reflex, explains many anomalies in the present concepts of OAB. It cannot be argued that urine loss is the endpoint of OAB. Yet, it is often observed during urodynamic testing, that in patients with urge symptoms, urine is lost with no detectable detrusor pressure. This observation can only be explained if OAB is the urodynamic expression of a prematurely activated micturition reflex, and it is explained as follows: (1) an external striated muscle mechanism actively opens out the outflow tract during micturition; 4 (2) at a diameter of 4 mm, no significant detrusor pressure is required to expel urine at a flow rate of 8 ml/sec. 5 Another explanation for “different types of urgency” 1 is vari- ation. No two humans are the same, and they may not only have different sensory pathways and perceptions, but they may perceive symptoms differently on a day-to-day basis within themselves. Micturition has many complex feedback reflexes as demonstrated by Barrington, 6 and there is some evidence that the feedback control mechanisms may be chaotic, stable within a defined range of afferent feedback, but unstable when the vol- ume of afferents proceeds beyond a critical mass. 2 Once again, most such mysteries concerned with urgency disappear if OAB is classified as a prematurely activated, but otherwise normal micturition reflex. The question asked by the authors, “Is urgency an all or none phenomenon” 1 is profound, not only in its essence, but in its implications. If the sensation of urgency can be modulated by squeezing or supporting the bladder base, 2 then it is potentially curable surgically. This has been demonstrated many times in patients with mixed incontinence, whereby simultaneous cure of both stress and urge incontinence symptoms has been achieved by placement of a midurethral sling. More recently, an association has been noted between OAB and pelvic organ prolapse. 7 Furthermore, urge symptoms have been cured in the absence of stress incontinence by repair of the posterior (uterosacral) suspensory ligament of the vagina. 8--10 The ratio- nale for surgical cure of urgency is that the organs, bladder and vagina, are stretched by the pelvic muscles, which in turn, contract against the suspensory ligaments. According to the Integral Theory, stretching the vagina is an essential element in modulating urge symptoms. A stretched vagina supports of the bladder base stretch receptors, and decreases the number of afferent impulses to the brain. Repair of the anterior (pub- ourethral) and posterior (uterosacral) suspensory ligaments restores this control mechanism for urgency by restoring the strength of muscle contraction, as the ligaments are the effective insertion points of these muscles. We comment on “Research Priorities” in italics • Evaluate if the sensation of urgency can be modulated. Can the intensity of urgency be decreased?This has been demonstrated clinically and urodynamically. 2 Indeed urge can be also exac- erbated by pressing the bladder base area of vagina forwards towards the pubic b one. • Evaluate the existence of different sensations of urgency. Does the character of the urgency sensation differ between patients with OAB or bladder pain syndrome?The authors have answered this question with reference to the complexity of urge production and control. To this can be added variation. • Do different forms of urgency have a different outcome towards treatments (bladder training, drugs, neuromodu- lation).If, as we believe, urgency is mainly a prematurely activated, but otherwise normal micturition, 2,3 then all treat- ments apply equally. P.E.P. Petros ∗ University of Western Australia, Perth, WA, Australia P. Richardson University of Central Queensland, Rockhampton, Qld, Australia REFERENCES 1. DeWachter S, Phil Hanno P. Urgency: All or none phenomenon? Neurourol Urodyn 2010;29:616--7. Christopher Chapple led the review process. ∗ Correspondence to: P.E.P. Petros, Wellington Q1 St Perth, Perth, WA 6000, Australia. E-mail: kvinno@highway1.com.au,kvinno@highway1.com.au OAB Can Be Modulated by External Musculo-Elastic Forces Received 19 May 2010; Accepted 27 May 2010 Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nau.20969 © 2010 Wiley-Liss, Inc. NAU10-0141(20969)