Catálogo de publicaciones - libros

Webster’s dictionary defines continence as “the ability to retain a bodily discharge voluntarily”. The word has its origins from the Latin or , which means “to hold”. The anorectum is the caudal end of the gastrointestinal tract, and is responsible for fecal continence and defecation. In humans, defecation is a viscero somatic reflex that is often preceded by several attempts to preserve continence. Any attempt at managing anorectal disorders requires a clear understanding of the anatomy and the integrated physiologic mechanisms responsible for maintaining continence.

This chapter focuses on the prevalence and incidence rate of faecal incontinence in the general population and specific subgroups, including the elderly and children. Epidemiological definitions are described, and problems with measuring faecal incontinence are discussed. Descriptive studies of prevalence and incidence rates are reviewed, including demographic determinants and the reliability of the prevalence estimates. A thorough discussion of risk factors for the development of faecal incontinence is covered elsewhere in this volume. Having highlighted the need for valid, reliable measurement tools, an example of such a tool is given for use in epidemiologic studies.

The ability to control evacuation, as discussed in Chapter 1, is guaranteed by many factors. These include intact anal sphincter mechanism, compliant reservoir, efficient evacuation, stool volume and consistency, intestinal motility, pelvic floor structural integrity, cortical awareness, cognitive function, mobility and access to facilities. Normal defecation is a process of integrated somatovisceral responses, which involve coordinated colo-recto-anal function []. Incontinence occurs when one or more of these mechanisms are impaired and the remaining mechanisms are unable to compensate. Although integrity of the sphincteric mechanism plays a major part, there are other important aspects, such as stool volume and consistency, colonic transit, rectal compliance and sensation, anorectal sensation and anorectal reflexes []. In this chapter, all these aspects are discussed separately, but in the majority of cases (80% according to Rao et al. []), the cause of faecal incontinence (FI) is multifactorial [, ].

Continence is a highly complex physiological function requiring coordinated activity of brain and central nervous system (CNS), autonomic and enteric nervous systems; a gastrointestinal tract of adequate length and biomechanical properties; and a competent anal sphincter complex, many components of which remain incompletely understood. In a minority of cases, for example incontinence immediately following fistulotomy for a high anal fistula in an otherwise “normal” individual, the cause-effect relationship is clear. For the majority, however, temporal relationships are not so evident, e.g. onset of symptoms several decades following a clinically uneventful vaginal delivery but one in which covert sphincter damage occurred, in which association between event and symptoms is less clear, and in which the event may be just one component of a multifactorial aetiology. Structural sphincteric causes of incontinence are relatively easy to investigate; at the most simplistic level, faecal continence depends upon anal pressure being higher than rectal pressure, and that this situation may be maintained predominantly by internal anal sphincter function, augmented at times of increased rectal pressure by voluntary anal muscle contraction, reflex or conscious, and orchestrated by intact sensation.

There are many routes to becoming a patient with faecal incontinence (FI), many aetiologies of the disorder, and many personal histories. The “meaning” of the FI will be different for each patient, and his or her way of managing it will depend not only on aetiology but also on a number of personal, social and medical factors. Is the FI secondary to a medical or surgical mishap, or is it the by product of a life-saving surgical resection, an “act of God”, or an “act of man”? Has the FI been with the patient since childhood, and has he or she developed coping strategies; or is it of recent onset and as yet “new”, foreign and unmanageable? What medical support is available to the patient? What emotional support-from family, partner, friends and work associates-is available? Is the partner supportive, or resentful and disgusted? What habitual defence mechanisms do, the patient use in order to deal with adversity, and are these mechanisms overall successful or counterproductive?

Given the psychological, social, and functional impacts that fecal incontinence (FI) has on an individual, the assessment of health-related quality of life (HRQoL) is an important consideration when evaluating the efficacy of treatment. An individual with FI faces a serious set of challenges in living life, and as a result, providers are also faced with consideration of these issues in providing treatment. For example, the implantation of an artificial sphincter is about more than technical procedures; it is also about its impact on the individual’s ability to live life.

Health care expenditure in the most economically advanced countries seems to have spiraled out of control over the last few decades. There are three main reasons accounting for this situation: ageing of the population has led to an increase in the numbers requiring health care services, the accelerating pace of technological development has given rise to new techniques that have improved the quality of treatment, and with the introduction of new, increasingly costly, products, patient expectations have changed and patients thus demand better medical treatment. The combination of these three factors has resulted in health care spending becoming increasingly difficult to control.

Besides physiologic investigations and radiology imaging, diagnosis of fecal incontinence requires accurate clinical assessment. By means of a structured scheme, clinical assessment aims to evaluate the whole picture: whether the patient is really incontinent, the etiology of the incontinence, and the nature and severity of the problem. Nevertheless, we must keep in mind that when treating an individual patient, these data may not be enough to define the pathophysiology of the symptom and, therefore, we need the investigations we mentioned initially.

Fecal incontinence is a consequence of functional disturbances in the mechanisms that regulate continence and defecation. In this chapter, we review the functional anatomy and physiology of the anorectum, pathogenic mechanisms, and diagnostic approaches for fecal incontinence.

Endoanal ultrasound (EUS) was introduced 20 years ago by urologists to evaluate the prostate. Later, EUS was extended to other specialists-; first to stage rectal tumors, and next to investigate benign disorders of the anal sphincters and pelvic floor.