Keywords

1 History of Anal Incontinence

All animals with a digestive system and an anus are generally provided with a sphincter system (a circular muscular structure) that creates rhythmicity in the expulsion of feces. Both humans and higher animals regulate defecation with a continence mechanism. The peristalsis that moves the feces down to the rectum is not controlled by will but by the vegetative nervous system, and therefore the only way in which animals regulate the elimination of feces is by retaining them with the mechanism of continence. In animals, continence is relevant for social interactions: with the deposition of excrement in specific places, some animals mark their territory or demonstrate their fertility. For that purpose many animals use their legs and tails to scatter droppings at a distance and thus cover wider areas.

In humans, continence is naturally acquired after some time (usually 3–4 years) but becomes important with the beginning of social life; it is necessary to separate this act from other people, not out of modesty (which will appear only centuries later), but for the management of excrement.

As evidenced by many archaeological findings, the Romans had collective latrines where they used to have discussions while defecating (Fig. 1.1).

Fig. 1.1
A photo of the common washroom used in ancient Rome. It has two sections on the floor surrounded by cemented area at an elevation.

The communal Roman latrine at Ostia, Italy (Photo by Carole Raddato, reproduced under CC-BY-SA license from https://www.flickr.com/photos/carolemage/6681231029/in/photostream/)

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Whereas the first description of urine incontinence dates back to 1500 B.C. (Ebers Papyrus), no data are available regarding the first description of fecal incontinence in ancient times [1]. Its first description was as a symptom of rectal prolapse.

Andreas Vesalius performed dissections on cadavers and described the colon, rectum and anus in meticulous detail, as illustrated in his De Humani Corporis Fabrica, published in 1543. The anal sphincters as well as the levator ani muscle were clearly described by the author. However, the first illustration of the anal sphincter can be found in Leonardo da Vinci’s anatomical drawing of the rectum from the fifteenth century. This drawing depicts the anal sphincter as a flower with five different petal-shaped muscular structures and is accompanied by a theory on its functioning (Fig. 1.2). The five-petal structure may derive from the hemorrhoids: three major and two minor.

Fig. 1.2
Drawings of the state of muscles surrounding the anus. In drawing a, the muscles are elongated, thus increasing the length of the hollow passage. In drawing b, the muscles are closed and constricted around the anus.

Leonardo da Vinci’s representation of the anal sphincter in relaxed (left) and contracted (right) position (details redrawn from Leonardo’s original drawing, by courtesy of Roberto Toderico)

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No detailed information on physiology was known at that time. Nevertheless, the risks and consequences of vaginal delivery on fecal incontinence were already known in Rome in the second century A.D. but repair of the injured anal canal was not described by the Romans [2].

Until the eighteenth century, the theory that explained continence was entirely based on the muscular layer of the rectum which pushed the feces outside the anus (Jean Astruc).

In 1835, Daniel Oliver wrote his First Lines of Physiology in which he stated that “the concurrence of the voluntary muscles with the action of the intestine itself, is indispensable to overcome the contraction of the sphincter of the rectum”, designing the first scientific theory [3]. The theory of a rectal “reservoir” and a muscular sphincter complex was then refined and improved in the twentieth century by two great scientists of the colon and rectum: Alan Park and Ahmed Shafik [4, 5]. Their vision of the anatomy and physiology of the rectum and anus are still a key element of today’s theories.

2 History of Treatments for Anal Incontinence

2.1 Colonic Irrigation and Colostomy

Colonic irrigation was the first treatment described for anal incontinence although this was not its proper and exclusive indication; already in the fifth century B.C. the Egyptians “cleansed” themselves on three consecutive days every month, by using enemas to purify their body, as reported by Herodotus. This technique was also recorded in the Babylonian and Assyrian tables and in Hindu medicine. Though widely used through the centuries, no data were reported on the outcomes of colonic irrigation until the modern era.

The first surgical treatment for anal incontinence was stoma creation (first performed in 1776 by Pillore [6]); as in the case of colonic irrigation, this technique was mainly adopted for conditions other than incontinence.

2.2 Anal Sphincter Repair

The first description of a successful sphincter repair dates back to 1882; Warren performed a vaginal mucosal flap to protect the repair of the lacerated rectum and anus [7]. This technique was also reported by other authors in case series showing good results in the short-term follow-up [8].

Many techniques for the correction of incontinence caused by sphincter damage were subsequently developed by different surgical teams [9], but all of them were based mainly on end-to-end sphincter repair, which often had high failure rates [10, 11]. The first modern technique, overlapping sphincteroplasty, was developed in 1973 as an improvement of end-to-end repair. This technique is still performed with excellent results [12] and is also reported in the guidelines as a standard surgical treatment [13].

As regards “idiopathic” incontinence, however, it was not until 1975 that the first surgical technique was reported. That year, Sir Alan Parks described the so-called “postanal repair”, a technique aiming to increase the length of the anal canal, restore the anorectal angle, and create a flap valve mechanism. The promising short-term results of this technique were less favorable in the long-term follow-up, mainly because of misdetection of subclinical anterior sphincter defect after delivery [14].

In 1991, the introduction of endoanal ultrasound led to a dramatic change of view regarding the etiology of anal incontinence [15], and many cases of idiopathic incontinence could now be labelled as delivery sphincter damage and properly repaired with overlapping sphincteroplasty [16]. Postanal repair is now confined to a small minority of patients with anal incontinence and most of the international guidelines do not recommend it.

2.3 Muscle Transposition and Artificial Sphincter

Muscle transposition techniques mainly derived from the first experience with muscle fiber transposition for ocular palsy (1908, Hummelsheim) [17]. In the first half of the twentieth century, the idea of transposing muscle fibers or fascia to reinforce a weakened or damaged sphincter was developed. The first techniques based on anal encirclement by fascia date back to Harvey Stone in 1932 [18, 19] and were later modified in 1941 [20]; the results were promising, with a reported success rate of 70%. Other authors chose to suture together muscle fibers from both gluteal muscles anterior to the rectum, thus suspending it in a kind of muscular “hammock” [21, 22]. Merging these approaches, in 1952 Pickrell codified his “gracilis muscle transplant” that was later to take his name [23]. This technique is now performed with an implantable electrical pulse generator (stimulated muscle transposition) and will be discussed later in this book.

The first artificial sphincter for human use was developed for the treatment of urinary incontinence in 1973 by American Medical Systems (AMS, Minnetonka, MN, USA) and was later applied to anal incontinence by Christiansen and Lorentzen in 1987 [24]. New specific devices have been developed since then but, considering their recent introduction, they will be thoroughly discussed in another chapter of this book.

2.4 Bulking Agents

Like all innovators, Ahmed Shafik not only developed a theory of the mechanism of anal continence but also proposed a new kind of treatment option: the use of bulking agents. In 1993 he published a case series on polytetrafluoroethylene injection for the treatment of partial fecal incontinence [25], with no complications reported and with promising results (improvement or cure in all cases). This technique was then reproduced with the aid of endoanal ultrasound to improve proper positioning of the agent, and now all bulking agents require ultrasound-guided positioning.

New technologies and new materials developed during the last twenty years have expanded this field of incontinence treatment with continuous news from scientific research. On the other hand, this fragmentation of materials and techniques has made it difficult to compare the results achieved with bulking agents and therefore the evidence to support their use has remained scarce.

2.5 Other Treatments and Techniques

Many other invasive and noninvasive treatments are now available for anal incontinence (sacral nerve stimulation, biofeedback, etc.) but, because their development is recent, they will be discussed in a separate chapter.