eMedicine Specialties > General Surgery > Colorectal

Fistula-in-Ano: Treatment

Author: Dennis F Zagrodnik II, MD, FACS, Consulting Staff, Premier Surgical of Wisconsin, SC
Contributor Information and Disclosures

Updated: Jul 16, 2009

Treatment

Medical Therapy

No definitive medical therapy is available; long-term antibiotic prophylaxis and infliximab may have a role in recurrent fistulae in patients with Crohn disease.

Surgical Therapy

Fistulotomy/fistulectomy (See image below and Image 4)13,14,15

Schematic of intersphincteric and low transsphinc...

Schematic of intersphincteric and low transsphincteric fistulotomy.

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Schematic of intersphincteric and low transsphinc...

Schematic of intersphincteric and low transsphincteric fistulotomy.


  • The laying-open technique (fistulotomy) is useful for 85-95% of primary fistulae (ie, submucosal, intersphincteric, low transsphincteric).
  • A probe is passed into the tract through the external and internal openings.
  • The overlying skin, subcutaneous tissue, and internal sphincter muscle are divided with a knife or electrocautery, thereby opening the entire fibrous tract.
  • At low levels in the anus, the internal sphincter and subcutaneous external sphincter can be divided at right angles to the underlying fibers without affecting continence. This is not the case if the fistulotomy is performed anteriorly in female patients. If the fistula tract courses higher into the sphincter mechanism, seton placement should be performed.
  • Curettage is performed to remove granulation tissue in the tract base.
  • Complete fistulectomy creates larger wounds that take longer to heal and offers no recurrence advantage over fistulotomy.
  • Opening the wound out on the perianal skin for 1-2 cm adjacent to the external opening with local excision of skin promotes internal healing before external closure.
  • Some advocate marsupialization of the edges to improve healing times.
  • Perform a biopsy on any firm, suggestive tissue.

Seton placement16

A seton can be placed alone, combined with fistulotomy, or in a staged fashion. This technique is useful in patients with the following conditions:

  • Complex fistulae (ie, high transsphincteric, suprasphincteric, extrasphincteric) or multiple fistulae
  • Recurrent fistulae after previous fistulotomy
  • Anterior fistulae in female patients
  • Poor preoperative sphincter pressures
  • Patients with Crohn disease or patients who are immunosuppressed

Setons have 2 purposes beyond giving a visual identification of the amount of sphincter muscle involved. These are (1) to drain and promote fibrosis and (2) to cut through the fistula. Setons can be made from large silk suture, silastic vessel markers, or rubber bands that are threaded through the fistula tract.

  • Single-stage seton (cutting)  
    • Pass the seton through the fistula tract around the deep external sphincter after opening the skin, subcutaneous tissue, internal sphincter muscle, and subcutaneous external sphincter muscle.
    • The seton is tightened down and secured with a separate silk tie.
    • With time, fibrosis occurs above the seton as it gradually cuts through the sphincter muscles and essentially exteriorizes the tract.
    • The seton is tightened on subsequent office visits until it is pulled through over 6-8 weeks.
    • A cutting seton can also be used without associated fistulotomy. (See image below and Image 5.)


Schematic of high transsphincteric fistulotomy wi...

Schematic of high transsphincteric fistulotomy with seton.

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Schematic of high transsphincteric fistulotomy wi...

Schematic of high transsphincteric fistulotomy with seton.

  • Two-stage seton (draining/fibrosing)
    • Pass the seton around the deep portion of the external sphincter after opening the skin, subcutaneous tissue, internal sphincter muscle, and subcutaneous external sphincter muscle.
    • Unlike the cutting seton, the seton is left loose to drain the intersphincteric space and to promote fibrosis in the deep sphincter muscle.
    • Once the superficial wound is healed completely (2-3 mo later), the seton-bound sphincter muscle is divided.
    • Two studies (74 patients combined) support the 2-stage approach with a 0-nylon seton. Once wound healing is complete, the seton is removed without division of the remaining encircled deep external sphincter muscle. The researchers reported eradication of the fistula tract in 60-78% of cases.

Mucosal advancement flap17,18

  • Mucosal advancement flap is reserved for use in patients with chronic high fistula but is indicated for the same disease process as seton use.
  • Advantages include a 1-stage procedure with no additional sphincter damage.
  • A disadvantage is poor success in patients with Crohn disease or acute infection.
  • This procedure involves total fistulectomy, with removal of the primary and secondary tracts and complete excision of the internal opening.
  • A rectal mucomuscular flap with a wide proximal base (2 times the apex width) is raised.
  • The internal muscle defect is closed with an absorbable suture, and the flap is sewn down over the internal opening so that its suture line does not overlap the muscular repair.

Preoperative Details

  • Rectal irrigation with enemas should be performed on the morning of the operation.
  • Anesthesia can be general, local with intravenous sedation, or a regional block.
  • Administer preoperative antibiotics.
  • Prone jackknife position with buttocks apart is the most advantageous position.

Intraoperative Details

  • Examine the patient under anesthesia to confirm the extent of the fistula.
  • Identifying the internal opening to prevent recurrence is imperative.
  • A local anesthetic block at the end of the procedure provides postoperative analgesia.

Postoperative Details

Most patients can be treated in an ambulatory setting with discharge instructions and close follow-up care.

Follow-up

  • Sitz baths, analgesics, and stool bulking agents (eg, bran, psyllium products) are used in follow-up care.
  • Frequent office visits within the first few weeks help ensure proper healing and wound care.
  • Importantly, ensure that the internal wound does not close prematurely, causing a recurrent fistula. Digital examination findings can help distinguish early fibrosis.
  • Wound healing usually occurs within 6 weeks.

Complications

Early postoperative

  • Urinary retention
  • Bleeding
  • Fecal impaction
  • Thrombosed hemorrhoids

Delayed postoperative

  • Recurrence
  • Incontinence (stool)
  • Anal stenosis: The healing process causes fibrosis of the anal canal. Bulking agents for stool help prevent narrowing.
  • Delayed wound healing: Complete healing occurs by 12 weeks unless an underlying disease process is present (ie, recurrence, Crohn disease).

More on Fistula-in-Ano

Overview: Fistula-in-Ano
Workup: Fistula-in-Ano
Treatment: Fistula-in-Ano
Follow-up: Fistula-in-Ano
Multimedia: Fistula-in-Ano
References
Further Reading
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References

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  5. Hamalainen KP, Sainio AP. Incidence of fistulas after drainage of acute anorectal abscesses. Dis Colon Rectum. Nov 1998;41(11):1357-61; discussion 1361-2. [Medline].

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  13. American Society of Colon and Rectal Surgeons. Practice parameters for treatment of fistula-in-ano--supporting documentation. The Standards Practice Task Force. Dis Colon Rectum. Dec 1996;39(12):1363-72. [Medline].

  14. Ho YH, Tan M, Leong AF, Seow-Choen F. Marsupialization of fistulotomy wounds improves healing: a randomized controlled trial. Br J Surg. Jan 1998;85(1):105-7. [Medline].

  15. Sangwan YP, Rosen L, Riether RD, Stasik JJ, Sheets JA, Khubchandani IT. Is simple fistula-in-ano simple?. Dis Colon Rectum. Sep 1994;37(9):885-9. [Medline].

  16. McCourtney JS, Finlay IG. Setons in the surgical management of fistula in ano. Br J Surg. Apr 1995;82(4):448-52. [Medline].

  17. Seow-Choen F, Nicholls RJ. Anal fistula. Br J Surg. Mar 1992;79(3):197-205. [Medline].

  18. Abbas MA, Lemus-Rangel R, Hamadani A. Long-term outcome of endorectal advancement flap for complex anorectal fistulae. Am Surg. Oct 2008;74(10):921-4. [Medline].

  19. Chung W, Kazemi P, Ko D, Sun C, Brown CJ, Raval M, et al. Anal fistula plug and fibrin glue versus conventional treatment in repair of complex anal fistulas. Am J Surg. May 2009;197(5):604-8. [Medline].

  20. Johnson EK, Gaw JU, Armstrong DN. Efficacy of anal fistula plug vs. fibrin glue in closure of anorectal fistulas. Dis Colon Rectum. Mar 2006;49(3):371-6. [Medline].

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  22. Loungnarath R, Dietz DW, Mutch MG, Birnbaum EH, Kodner IJ, Fleshman JW. Fibrin glue treatment of complex anal fistulas has low success rate. Dis Colon Rectum. Apr 2004;47(4):432-6. [Medline].

  23. Champagne BJ, O'Connor LM, Ferguson M, Orangio GR, Schertzer ME, Armstrong DN. Efficacy of anal fistula plug in closure of cryptoglandular fistulas: long-term follow-up. Dis Colon Rectum. Dec 2006;49(12):1817-21. [Medline].

  24. Safar B, Jobanputra S, Sands D, Weiss EG, Nogueras JJ, Wexner SD. Anal fistula plug: initial experience and outcomes. Dis Colon Rectum. Feb 2009;52(2):248-52. [Medline].

  25. Han JG, Xu HM, Song WL, Jin ML, Gao JS, Wang ZJ, et al. Histologic analysis of acellular dermal matrix in the treatment of anal fistula in an animal model. J Am Coll Surg. Jun 2009;208(6):1099-106. [Medline].

  26. Present DH, Rutgeerts P, Targan S, Hanauer SB, Mayer L, van Hogezand RA, et al. Infliximab for the treatment of fistulas in patients with Crohn's disease. N Engl J Med. May 6 1999;340(18):1398-405. [Medline].

  27. Ratto C, Gentile E, Merico M, Spinazzola C, Mangini G, Sofo L, et al. How can the assessment of fistula-in ano be improved?. Dis Colon Rectum. Oct 2000;43(10):1375-82. [Medline].

  28. Topstad DR, Panaccione R, Heine JA, Johnson DR, MacLean AR, Buie WD. Combined seton placement, infliximab infusion, and maintenance immunosuppressives improve healing rate in fistulizing anorectal Crohn's disease: a single center experience. Dis Colon Rectum. May 2003;46(5):577-83. [Medline].

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Keywords

fistula-in-ano, fistula, anus, anorectal fistula, hemorrhoidectomy, sphincterotomy, perianal fistula, anorectal abscess, Crohn disease, Crohn's disease, anal fissures, actinomycoses, anorectal sepsis, intersphincteric fistula, transsphincteric fistula, trans-sphincteric fistula, suprasphincteric fistula, supra-sphincteric fistula, extrasphincteric fistula, extra-sphincteric fistula, Goodsall rule, Parks classification

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Contributor Information and Disclosures

Author

Dennis F Zagrodnik II, MD, FACS, Consulting Staff, Premier Surgical of Wisconsin, SC
Dennis F Zagrodnik II, MD, FACS is a member of the following medical societies: American College of Chest Physicians, American College of Surgeons, American Medical Association, Phi Beta Kappa, Society of American Gastrointestinal and Endoscopic Surgeons, Southeastern Surgical Congress, and Wisconsin Medical Society
Disclosure: Nothing to disclose.

Medical Editor

Oscar Joe Hines, MD, Assistant Professor, Department of Surgery, University of California at Los Angeles School of Medicine
Oscar Joe Hines, MD is a member of the following medical societies: Alpha Omega Alpha, American Association of Endocrine Surgeons, American College of Surgeons, Association for Academic Surgery, Society for Surgery of the Alimentary Tract, and Society of American Gastrointestinal and Endoscopic Surgeons
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

David L Morris, MD, PhD, Professor, Department of Surgery, St George Hospital, University of New South Wales, Australia
Disclosure: RFA Medical None Director; MRC Biotec None Director

CME Editor

Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy
Paolo Zamboni, MD is a member of the following medical societies: American Venous Forum and New York Academy of Sciences
Disclosure: Nothing to disclose.

Chief Editor

John Geibel, MD, DSc, MA, Vice Chairman, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital
John Geibel, MD, DSc, MA is a member of the following medical societies: American Gastroenterological Association, American Physiological Society, American Society of Nephrology, Association for Academic Surgery, International Society of Nephrology, New York Academy of Sciences, and Society for Surgery of the Alimentary Tract
Disclosure: AMGEN Royalty Other

 
 
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