The exact incidence of fecal incontinence is unknown. Nevertheless, it is estimated that 0,5 to 1,5 % of the normal population is suffering from this disease; if soiling is included the incidence rises up to 5%. In geriatric wards the incidence is as high as 30% ; in psychiatric wards up to 50%.

Several factors are responsible for continence (Fig. 1) Therefore treatment options are variable. To achieve a high success rate, clinical and physiological work up must be demanded.

Investigations

The first step in evaluating patients is always an exact history. Questions should focus on type and degree of incontinence as well as on alteration of the patient’s life style. An incontinence scoring system to rate incontinence more accurate is often used.

The next step in clinical evaluation is inspection. A thin or scared perineum or other morphological changes like a patulous anus , tags or prolapsing hemorrhoids as well as an overt rectal prolapse or a ballooning of the pelvic floor during straining may give a hint to the possible etiology of the fecal incontinence. Pseudoincontinence , soiling due to a hygienic problem , must be excluded.

A dynamic digital-rectal examination meaning investigation during straining, relaxing and squeezing, should follow. Tumors, fissures can be excluded. Furthermore sphincter pressures can be estimated and amobile segments as after sphincter disrupture can be palpated.

Endoscopic investigations ( coloscopy and proctoscopy ) are mandatory to exclude structural disorders like polyps , tumors or cicumferential intussusception. In special situations like in patients with overflow incontinence a barium enema may be enough.

If basic investigation methods fail to show any evidence for fecal incontinence, a more sophisticated physiologic work up is necessary.

Physiologic tests

Anal manometry: Anal manometry is most useful to get objective data on patient’s anal pressures. Mean and maximal resting pressures reflect the status of the function of the internal sphincter ; mean and maximal squeeze pressures of the external sphincter muscle. Furthermore the length of the high pressure zone, the recto-anal-inhibitory reflex ( sampling reflex) , rectal sensibility and capacity as well as the rectal compliance can be estimated.

Anal endosonography (AEUS) : Endoanal ultrasound is the most important test to rule out structural lesions such as isolated or combined sphincter muscle defects. The investigation is simple, painless , accurate and can be repeated, if necessary. Furthermore EUAS is used for follow up after surgical correction of fecal incontinence.

Neurophysiologic assessment : EMG of the pelvic floor with concentric needles or a single fiber EMG should nowadays only be done in selected patients, as this test is painful. Pudendal nerve terminal motor latency measurements (PNTML) should be done, as this test may have influence on prognosis after surgical corrections of sphincter defects.

Other tests : In selected cases other tests like MRI, defecography, fecal- flow-metry, scintigrafic evacuation procedures as well as electrosensibility studies may be useful.

Surgical options
If conservative treatment options fail, patients may be considered for surgical treatment. The options are listed in Figure 3. Simple encirclement procedures like the Thiersch wire are obsolete.

Sphincteroplasty

Patients best suited for surgical corrections are those in whom the incontinence is secondary to an anterior sphincter defect. Obstetric and iatrogenic etiologies are among the most common surgically correctable fecal incontinence. An overlapping repair is preferable ( 5 ) to a simple apposition of the sphincter muscles. The sphincter defect should not exceed more than “three hours” or 90 ° in EUAS, as overlapping may become technical impossible (Fig.4.). Some centers are suturing the internal sphincter muscle as a special pronounced layer, some do not. Sphincteroplasty can be done even in elderly patients. Success rates are expected in about three quarters of patients. However, recent studies have shown a worse long term prognosis ; especially in patients with concomitant pudendal neuropathy evaluated by PNTML studies preoperatively.

Postanal repair, Total pelvic floor repair
A frequent method popularized by Sir Alan Parks from St.Mark`s Hospital, London , in the eighties was the postanal repair. The idea was by an intersphincteric approach to sharpen the ano-rectal angle and therefore improving incontinence. Long term results (>5 years) are around 50%( 9 ). However, in special situations this simple operation can be the treatment option of choice ; in an elderly patient if no sphincter defect is visible on EAUS.

Total pelvic floor repair , a combination of postanal repair and preanal levatorplasty (reefing), recommended by Keighley et al, is of no further benefit in long term.

Stimulated graciloplasty
Encirclement procedure of the anus with the gracilis muscle was first described by Pickrell as early as 1952. However, due to lack of technical knowledge, this operation gave bad results. Since the advent of stimulated devices, similiar to cardiac peacemaker, this operation method has seen an increasing interest among colorectal surgeons. In experienced hands success rate can be as high as 78 %. However, complication rate is still very high and in a range of about 54 %.

Artifical bowel sphincter (ABS)
Another new treatment option is the implant of an artificial prosthesis. The procedure seems to be simple, but the infection rate resulting in explantation of this sphincter is about 35%. At the moment no definitive answer about this device, which is popular among urologists since more than 20 years, can be given.

Sacral Nerve Stimulation (SNS)
A new approach treating fecal incontinence is the direct stimulation of the sacral root S2,S3 or S4 . If a test stimulation is successful, a permanent stimulation device similar to the cardiac peacemaker can be implanted. At the moment the number of patients treated with this method is very small and no long term results are available

Stoma

Probably the safest, best and most easiest way to handle patients with fecal incontinence is fashioning of a colostoma. Furthermore, irrigation can improve life quality . Even among the choice of many different and partly high sophisticated surgical treatment options, the creation of a stoma is still a good operation method.

Conclusion
Surgical treatment of fecal incontinence must be tailored to the individual patient; physiologic tests help selecting the right patient for the right operation.

References
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Berooz Salehi, MD
Department of General Surgery
Surgery
Karl-Franzens University School of Medicine

Johann Pfeifer, MD
Professor of Surgery
Department of General Surgery
Surgery
Karl-Franzens University School of Medicine