The Urinary Sphincter PDF

Preface

A number of books on urinary incontinence have been published in the last 10 to 15 years. It would have been easier for us to write just another volume dealing with incontinence. It was not to be provocative or to make our work harder that we chose this apparently very limited topic: the urinary sphincter.

Since we deal with bladder dysfunction, incontinence, dyssynergia, retention, and the entire spectrum of lower urinary tract symptoms, we have learned the key position the urinary sphincter occupies in lower urinary tract function. It is becoming increasingly evident that normal and abnormal functioning of the urethra may have a tremendous impact on the functioning of the lower urinary tract and, by extension via the bladder, ultimately on the upper urinary tract as well. It appears that dysfunction of the urethral sphincteric mechanism will often influence bladder function, but the inverse is not inevitably the case. In other words, the urethral sphincter seems to have the predominant role in urethrovesical function.

Probably for didactic reasons, we are used to dividing the urethral sphincter into internal and external, proximal and distal, lisso-sphincter and rhabdosphincter, and so on. As we now know, there is no urinary sphincter, as such, in the sense of an anatomical structure made up of circular muscle fibers. Evidently, it would be much better to design the urethra as a unique sphincteric mechanism built with different muscular, nervous, vascular, connective, and epithelial structures that act together as a single functional unit. Its unique physiological role is to close the bladder outlet during the filling phase, ensuring continence, and to open up during voiding, allowing bladder emptying. This apparently simple anatomical structure, however, represents a highly sophisticated and complex functional unit. It is in structural continuity with the bladder and functionally integrated within the pelvic floor.

The book is divided into six parts. The first describes the anatomy and function of the male and female sphincteric mechanism as well as its interconnections with the pelvic floor. References to embryology and observations in infancy contribute to a better understanding of different pathological phenomena in adults and elderly subjects.

The second part, after a review of the epidemiology of the dysfunctional sphincter, analyzes in detail the pathophysiology of three possible functional abnormalities of the urinary sphincter—incompetency, hypertony, and dyssynergia—as well as the behavior of the sphincter when associated with genital prolapse in females.

Evaluation of sphincter competency is not an easy task. Clinical, urodynamic, electrophysiological, and imaging techniques are developed extensively in the third part of the book. Most of these tools explore the very close dynamics existing between the bladder and the urethra. The multiplicity of exploratory techniques reflects the difficulty we have in assessing sphincter function. Diagnosis of bladder-striated sphincter dyssynergia is not very difficult most of the time. Demonstrating sphincter incompetence is often challenging when, for example, decreased bladder compliance is one of the factors responsible for incontinence.

Treatment options are fully described in the fourth part of the book. A great deal of information is provided on lifestyle interventions, physiotherapy, disposable devices, pharmacological therapy, and the technique that "changed the face of the urological world," intermittent catheterization. It is important to be familiar with these techniques, their indications, and the results to expect from each, because most of the time they will be the first line of treatment. The surgical approach constitutes a large part of this section, including recent techniques, such as injectables, and different sling procedures that have now been widely adopted by the scientific community. The issue of autologous versus cadaveric or artificial slings is not yet settled. Injectables probably represent the greatest progress made in the last two decades in the treatment of sphincteric incompetence, even if we do not fully understand their mechanism of action. At present, the artificial sphincter seems to be the gold standard for the treatment of male intrinsic sphincter deficiency. All stents, sphincters, slings, and similar devices are the result of well-thought-out engineering work and bring viable solutions to otherwise hopeless patients, substantially improving their quality of life.

Finally, neurostimulators and neuromodulators have been developed as a result of extensive and remarkable animal work, in conjunction with the high-tech industry. They represent a major step forward in controlling sphincteric dysfunction. We are now able to modulate sphincteric activity to make it more efficient and better coordinated with bladder function. Progress in the neurocontrol of urethrovesical function will probably represent a major urological revolution in the twenty-first century. The control units of these neuromodulators will become as popular and widely used in the next 20 years as are cardiac pacemakers today.

The fifth part of the book is a synthesis of the treatment of three possible sphincteric dysfunctions: the incompetent, the dyssynergic, and the overactive sphincter. The reader will find a practical clinical approach to these problems with some algorithms that may be useful for students, teachers, and practicing physicians.

Finally, the sixth part of the book is a compilation of reports published so far on the standardization of terminology, methodology, and outcome measures elaborated by the International Continence Society. These reports are invaluable aids for those who are interested and actively involved in the study of urethrovesical function and dysfunction. They are the result of years of work and consultation and reflect the thoughts of two generations of highly specialized physicians.

We would like to thank each and every contributor who agreed to participate with us in this venture. They did some truly remarkable work and are principally responsible for the high quality of the book.

We also want to thank Carol Goldberg, who was responsible for the difficult secretarial support required in such an enterprise; Micheline Risler and Catherine Schick, who reviewed and corrected all references to adapt them to our standards; Raymond Bourdeau, who drew and modified the illustrations to provide uniformity throughout the book; and Ovid Da Sylva and his team, who corrected our numerous grammatical and vocabulary mistakes.

Finally, our warmest gratitude goes to our wives, Sylvie and Micheline, who sacrificed part of their family life during the long preparation of this book. Their constant encouragement allowed us to say "mission accomplished!"