Mucosal Advancement Flap For Treatment Of Anorectal Fistula

General remarks

Information

• For classification and diagnosis of perianal fistulas MRI is the most appropriate diagnostic tool
• The majority of patients with perianal fistula show epithelialization of the fistula tract, that might prevent closure of the tract. Curettage of perianal fistulae must therefore be considered an essential step in the surgical treatment of perianal fistula.
• Closure of the primary fistula opening using a biological anal fistula plug and anal flap advancement result in similar fistula healing rates in patients with high transsphincteric fistulae. These 2 strategies are superior to seton placement and fibrin glue.
• Given the low morbidity and relative simplicity of the procedure, the anal fistula plug is a viable alternative treatment for patients with high transsphincteric anal fistulas.

Treatment options

• A drainage seton. A safe option to provide adequate drainage. Surrounding tissue will get the opportunity to heal for future treatment. This option does not cure the fistula.
• Lay-open. The fistula is cut open. With this technique there is a risk of cutting to much sphincter tissue (depending on the position of the fistula) which can impair the sphincter's function leading to incontinence. Therefore this option is not suitable for high fistulas (e.g. crossing the entire anal sphincter). At least 2/3 of the sphincter should remain after the procedure.
• Cutting seton. A tied seton is tightened over time, resulting in gradually cutting through the sphincter. This technique can be used until the fistula is completely cured, or can be left in place until the fistula tract is lowered to a level allowing a safe lay-open technique. This technique can sometimes cause incontinence.
• Fistula plug. With this technique the fistula is plugged with a small stretched cone (plug) made of porcine small intestine submucosa. The plug is biodegradable allowing the fistula to heal almost physiologically. Success rates are reported up to 80%.
• Fibrin glue. In this technique the fistula tract is injected with biodegradable glue. However the anal fistula plug treatment shows better results when compared to fibrin glue injection.
• Mucosal advancement flap. In this technique the internal fistula opening is excised and covered with a flap of mucosal tissue. This technique can be combined with a fistula plug.

Step by step

1. Position patient in lithotomy position
2. Place the intra-anal retractor
3. Identify fistula site
4. Canulate and brush the fistula tract (or flush with hydrogen peroxide,or both)
5. Excise the intra-anal fistula site (elliptical shape)
6. Create a wide flap by extending the proximal anorectal wall upwards
7. Close the internal fistula opening with absorbable suture
8. Further dissect the flap above the fistula including a thin layer of internal sphincter
9. Prepare the advancement flap and optimize the size before suturing
10. Complete the repair with single sutures

References

Histological identification of epithelium in perianal fistulae: a prospective study. van Koperen PJ, Ten Kate FJ, Bemelman WA, Slors JF. Colorectal Dis. 2009 Apr 10. Fibrin glue in the treatment of anal fistula: a systematic review. Cirocchi R, Farinella E, La Mura F, Cattorini L, Rossetti B, Milani D, Ricci P, Covarelli P, Coccetta M, Noya G, Sciannameo F. Ann Surg Innov Res. 2009 Nov 14;3:12. Perianal fistulas: developments in the classification and diagnostic techniques, and a new treatment strategy. van Koperen PJ, Horsthuis K, Bemelman WA, Stoker J, Slors JF. Ned Tijdschr Geneeskd. 2008 Dec 20;152(51-52):2774-80 Treatment of transsphincteric anal fistulas: are fistula plugs an acceptable alternative. DWang JY, Garcia-Aguilar J, Sternberg JA, Abel ME, Varma MG. Dis Colon Rectum. 2009 Apr;52(4):692-7.