RECENT TRENDS IN MANAGEMENT OF FAECAL INCONTINENCE

Abstract

Continence of gas and stool is the ability to retain and expel gas and faeces at a socially appropriate place and time. Continence depends on a number of factors, notably normal anatomy and function of the internal and external anal sphincters and of the pelvic floor muscles, and normal anal and rectal sensation. Other variables that play a part in preserving continence are stool volume and consistency, intestinal transit and normal mental function. Anal incontinence is a disabling condition which, when severe, causes progressive social isolation, with a devasting psychological impact. It occurs more commonly in woman, in the elderly and in patients with physical limitation and poor health, and it affects approximately 2-5 percent of the adult general population. A comprehensive history and clinical examination in the initial assessment of patients is essential, but it is insufficient by itself and must be supplemented by other special investigation. A wide variety of physiological and morphological tests are available for the assessment of the anus and rectum. Although there is no clear correlation between manometric/neurophysiological testing and clinical symptomatology in patients with idiopathic faecal incontinence, there is considerable value in performing these tests before surgery in order to predict long-term outcome. Furthermore, anorectal investigation has revealed a large group of parous women who have occult sphincter trauma which may have a clinical impact as the woman get older. Endo-anal imaging is becoming the gold standard in the pre-operative determination of sphincter integrity and defines those patients who are most likely to benefit from surgical intervention. As the introduction of anal endosonography as a way of imaging enables accurate identification of the lesions causing faecal incontinence and has allowed rational planning of the treatment. Also, magnetic resonance imaging with an anal coil can be helpful in investigating para-anal structures or when the ultrasound findings are equivocal. Endosonography has largely replaced electromyography, although the latter may be useful when scaring makes interpretation of ultrasonography difficult. Pudendal nerve latency testing is less variable than was previously believed, as most patients have identifiable structural damage or muscular degeneration rather than neuropathy. A scoring system for the assessment of severity of faecal incontinence is required to gain an objective comparison of outcomes of both conservative and surgical treatments. Grading of incontinence is usually difficult and grading into objective criteria still carries a bias. A combination of objective and subjective criteria is probably best. Difficult types of scoring system are available that help in quatification of the severity of incontinence such as: the Cleveland score for its many advantages and William, s scoring system. The management of faecal incontinence depends on its aetiology and severity. In patients with established and troublesome faecal incontinence the choice lies between conservative measures or surgical repair of the sphincter apparatus. Treatment options for faecal incontinence lies between conservative and surgical measures. Most patients can be treated well conservatively. A high fibre diet or bulkforming agents to improve stool volume and consistency or the use of cleansing enemas are effective. Biofeedback and bowel training program have proven to be successful in increasing the voluntary contraction amplitude of the external anal sphincter and the pelvic floor. In patients with a mechanical defect of the anal sphincter, overlapping sphincteroplasty is the operation of choice and results in restoration of a normal squeeze pressure. Post-anal repair was introduced for the treatment of patients with neurogenic faecal incontinence. When an anterior levatorplasty and an internal sphincter plication are added, the total pelvic floor repair results are improved, with complete continence being achieved in two-thirds of patients. When none of the above treatment modalities is successful, a permenant colostomy may be created, the only other possibility being the creation of a new anal sphincter using an artificial device or autologous tissue. In such patients consideration should be given to some form of sphincter augmentation. Various muscles have been used, including gluteus maximus, Sartorius, adductor longus and most commonly, the gracilis. More recently, and because of the inconsistent results of skeletal muscles transposition, electro-stimulation was used to convert the muscle from a fast twitch muscle ( not ideal substitute for a sphincter function), into a slow, twitch, fatigue resistant one, suitable for sustained contraction as a sphincter. Variable techniques for gracilopasty are present including three stages procedure, bilateral graciloplasty and more recently single stage dynamic graciloplasty with a modified (split sling) technique. The use of artificial sphincter may expand with technical developments. The indication of (AAS) are usually the same as those for biological neosphincter. Additionally, AAS are useful in managing faecal incontinence of neuromuscular origin, such as myasthenia gravis or diabetic neuropathy. Addition of antegrade irrigation via a Malone stoma or colonic conduit may result in fewer conversions to a permenant stoma. In conclusion, from the above mentioned summary, there is a variety of surgical and non-surgical treatments are available, which should be tailored to the individual patient depending on the aetiology of incontinence.