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Editor: Samantha Morris

Date of lat Edit: 30/08/16

Current Definition - 2016
Faecal incontinence is the complaint of an involuntary loss of faeces. This can be to solid or liquid stool, and presents in different formats [1].

Passive faecal leakage is the involuntary soiling of liquid or solid stool without a sensation or warning or difficulty in wiping clean [1].

Overflow faecal incontinence is the seepage of stool due to faecal impaction [1].

Coital faecal incontinence is an involuntary loss of faeces occurring with vaginal intercourse [1].

Urge faecal leakage is where the loss of faeces is associated with an urge, but the individual cannot defer the bowel movement before reaching a toilet [2].

Old Definition(s)
The 2010 definitions are similar, and include the definitions of faecal incontinence, passive faecal leakage, coital faecal incontinence and urge faecal leakage [3]. However, overflow faecal incontinence was not included in previous definitions and is a new definition for 2016 [1]. There does not appear to be any definitions for faecal incontinence that are now thought to be incorrect and no longer used.


Perspectives and Controversies
Firstly, it is important to determine the type of faecal incontinence, as the preferred treatment method may differ. Simply trying to stop the incontinence episodes by firming up the stool, for example with loperamide, may work for those who have seepage of loose stool, perhaps due to a weakness of their sphincter muscles. However, in the case of overflow faecal incontinence this would actually make the problem worse, and instead removing the impaction and enabling complete defecation would be more appropriate.

Secondly, the term “overflow faecal incontinence”, itself can be misleading. Despite being a listed definition by the ICS [1], it has the potential to cause confusion in other languages. In fact, the term “overflow urinary incontinence” is not used for this reason, with the types of urinary incontinence classified differently [3]. However, this is an accurate and appropriate description for this type of faecal incontinence. Here, the leakage is that of loose stool from higher up the rectum flowing over impacted hard stool nearer the anus, thus the word “overflow” is an accurate description.


Mechanism
Faecalincontinence can be caused by a problem in one or more of three areas: i) rectal compliance or capacity; ii) stool consistency; and iii) the anal sphincter complex. These issues can be caused by a multitude of factors, including damage to the anal sphincters, systemic disease, neurological disease, and non-sphincter causes, for example dementia and diarrhea [4].

An issue with rectal compliance or capacity can cause faecal incontinence. A reduced rectal compliance, for example as seen in some spinal injuries, can result in the rectal pressure increasing beyond that of the anal sphincter complex, resulting in leakage of stool [5-6]. Patients with incontinence are also likely to have a reduced rectal capacity, where they can only store lower volumes of stool before leakage occurs [7].

Stool consistency can also cause faecal incontinence. If the stool is loose, continence becomes more difficult and seepage is more likely. However, if stool is hard, you can get overflow incontinence.

Thirdly, the function of the anal sphincters is to maintain continence and to co-ordinate defecation, thus when the sphincters are damaged, it is not surprising that faecal incontinence occurs. The internal anal sphincter is involuntary smooth muscle, and maintains the resting tone of the anal canal. The external anal sphincter, however, is voluntary skeletal muscle, and contacts on squeeze to prolong defecation [8]. Thus damage to either or both of these muscles, can lead to passive (internal) or urge (external) faecal incontinence. Structural damage can occur surgically, for example by a sphincterotomy or hemorrhoidectomy [9]. It can also occur during childbirth as an obstetric anal sphincter injury, in the case of a 3rd or 4th degree tear [10] or in the case of anal digitation. The sphincters can also be damaged functionally, rather than structurally, for example in systemic sclerosis or post radiotherapy treatment [2].

Furthermore, a lack of neurological control can also lead to faecal incontinence, and can impact both on sphincter function and rectal capacity/compliance. The internal and external anal sphincters are innervated by parasympathetic nerves from the S2-S4 and sympathetic nerves from the T11-L 1 levels of the spinal cord. These allow detection of faecal matter in the rectum and co-ordinate the anal sphincters to maintain contracted, until the individual consciously decides to defecate. Thus when this mechanism is damaged or weakened, for example in multiple sclerosis or spinal cord injury, the control is impaired and faecal incontinence can develop [11].


Therapies
As mentioned above, the reason for the faecal incontinence needs to be determined in order to establish the appropriate therapy and treatment modality. Treatment can be through drugs, conservative management or surgical management.

Drug management methods involve the use of constipating drugs to firm up the stool, e.g. loperamide and codeine; laxatives to empty the rectum, e.g. lactulose; or drugs to improve anal sphincter tone, e.g. phenylephrine gel [2].

Conservative management methods include biofeedback therapy, anal plugs, rectal irrigation, percutaneous tibial nerve stimulation and anal plugs. Biofeedback therapy, or pelvic-floor retraining therapy, can be used to treat faecal incontinence. Pelvic floor and anal sphincter exercises are taught using a variety of techniques and devices, aiming to strengthen the anal sphincter muscles and improve continence [12-13]. Anal plugs are used to contain the faecal in the rectum, preventing leakage, rather than improving the incontinence and anal function. It is useful in patients who fail or are unsuitable for other treatments [14]. Rectal irrigation introduces water through the anus aiming to clear out the rectum and for complete defecation. This then prevents faecal incontinence episodes as there is no faecal matter present to leak out [15]. Percutaneous Tibial Nerve Stimulation (PTNS) involves stimulation of the tibial nerve, which is thought to then stimulate the sacral nerve and aid neural control of the anal sphincters, reducing faecal incontinence episodes [16-17].

Surgical management methods include sacral neuromodulation, injectable bulking agents, artificial anal sphincters and sphincter repairs. Sacral neuromodulation involves an electrical stimulator implanted which stimulated the S3 and S4 nerve fibres, aiming to improve neural control [4]. Injectable bulking agents, for example the Gatekeeper prostheses, can be inserted into the intersphincteric space, aiming to close the anal sphincters and improve continence [18-19]. The same principle applies for mesh implants, for example Topas [20]. Surgery can also be performed to repair the anal sphincter is structurally damaged, for example an anterior sphincter repair, or to implant an artificial sphincter, e.g. FENIX [21-22].


References and Resources
  1. Sultan A. H., Monga A., Lee J., Emmanuel A., Norton C., Santoro G., Hull, T., Berghmans B., Brody S., Haylen B. T. “An international urogynaecological association (IUGA)/international continence society (ICS) joint report on the terminology for female anorectal dysfunction” Neurourology and Urodynamics DOI 10.1002/nau
  2. Omar M. I., Alexander C. E. “Drug treatment for faecal incontinence in adults” Cochrane Database of Systematic Reviews 2013 Issue 6 Art. No.: CD002116
  3. Haylen B. T., de Ridder D., Freeman R. M., Swift S. E., Berghmans B., Lee J., Monga A., Petri E., Rizk D. E., Sand P. K., Schaer G. N., International Urogynecological Association, International Continence Society “An international urogynecological association (IUGA)/international continence society (ICS) joint report on the terminology for female pelvic floor dysfunction” Neurourology and Urodynamics 2010 29(1): 4-20
  4. Thaha M. A., Abukar A. A., Thin N. N., Ramsanahie A., Knowles C. H. “Sacral neuromodulation for faecal incontinence and constipation in adults” Cochrane Database of Systematic Reviews 2015 Issue 8 Art No.: CD004464
  5. Trivedi P. M., Kumar L. and Emmanuel A. V. “Altered colorectal compliance and anorectal physiology in upper and lower motor neurone spinal injury may explain bowel symptom pattern” The American Journal of Gastroenterology 2016 111(4): 552-60.
  6. Awad R. A., Camacho S., Flores F., Altamirano E. and Garcia M. A. “Rectal tone and compliance affected in patients with fecal incontinence after fistulotomy” World Journal of Gastroenterology 2015 21(13): 4000-5
  7. Lam T. J., Kuik D. J. and Felt-Bersma R. J. “Anorectal function evaluation and predictive factors for faecal incontinence in 600 patients” Colorectal disease 2012 14(2): 214-23.
  8. Bhardwaj R., Vaizey C. J., Boulos P. B. and Hoyle C. H. “Neurogenic properties of the internal anal sphincter: therapeutic rationale for anal fissures” Gut 2000 46(6): 861-8.
  9. Lindsey I., Jones O. M., Smilgin-Humphreys M. M., Cunningham C. and Mortensen N. J. “Patterns of fecal incontinence after anal surgery” Diseases of the Colon and Rectum 2004 47(10): 1643-9.
  10. Wheeler T. L. 2nd and Richter H. E. “Delivery method, anal sphincter tears and fecal incontinence: new information on a persistent problem” Current Opinion in Obstetrics and Gynecology 2007 19(5): 474 – 9.
  11. Coggrave M., Norton C. and Cody J. D. “Management of faecal incontinence and constipation in adults with central neurological diseases” Cochrane Database of Systematic Reviews 2014 Issue 1 Art No.: CD002115
  12. Lee Y. Y. “What’s new in the toolbox for constipation and fecal incontinence?” Frontiers in Medicine 2014 1(5): 1-9.
  13. Norton C. and Cody J. D. “Biofeedback and/or sphincter exercises for the treatment of faecal incontinence in adults” Cochrane Database of Systematic Reviews 2012 Issue 7 Art No.: CD002111
  14. Deutekom M. and Dobben A. C. “Plugs for containing faecal incontinence” Cochrane Database of Systematic Reviews 2015 Issue 7 Art No.: CD005086
  15. Vollebregt P. F., Elfrink A. K., Meijerink W. J. and Felt-Bersma R. J. “Results of long-term retrograde rectal cleansing in patients with constipation or fecal incontinence” Techniques in Coloproctology 2016 doi:10.1007/s10151-016-1502-y
  16. Pena Ros E., Parra Banos P. A., Benavides Buleje J. A., Munoz Camarena J. M., Escamilla Segade C., Candel Arenas M. F., Gonzalez Valverde F. M. and Albarracin Marrin-Blazquez A. “Short-term outcome of percutaneous posterior tibial nerve stimulation (PTNS) for the treatment of faecal incontinence” Techniques in Coloproctology 2016 20(1): 19-24.
  17. Kelly S. L., Radley S. C. and Brown S. R. “Does percutaneous tibial nerve stimulation improve global pelvic function in women with faecal incontinence?” Colorectal Disease 2016 18(5): 158-63.
  18. Ratto C., Buntzan S., Aigner F., Altomare D. F., Heydari A., Donisi L., Lundby L. and Parello A. “Multicentre observational study of the Gatekeeper for faecal incontinence” The British Journal of Surgery 2016 103(3): 290-9.
  19. Maeda Y., Laurberg S. and Norton C. “Perianal injectable bulking agents as treatment for faecal incontinence in adults” Cochrane Database of Systematic Reviews 2013 Issue 2 Art No.: CD007959
  20. Mellgren, A., Zutshi, M., Lucente, V.R., Culligan, P., and Fenner, D.E. 2 “A posterior anal sling for fecal incontinence: results of a 152-patient prospective multicenter study.” American Journal of Obstetrics and Gynaecology 2016 214(3): 349-8
  21. Brown S. R., Wadhawan H. and Nelson R. L. “Surgery for faecal incontinence in adults” ” Cochrane Database of Systematic Reviews 2013 Issue 7 Art No.: CD001757
  22. AE Williams, J.M., Hulme, C., Brown, S.R., Lodge, J., Protheroe, D., and Jayne, D.G. “SaFaRI: sacral nerve stimulation versus the FENIX magnetic sphincter augmentation for adult faecal incontinence: a randomised investigation.” International Journal of Colorectal Disease, 2016 31(2): 465-472