Reprinted from December 2010 the Science Behind Positive Patient Outcomes RP1556 Supported and approved by the Science Behind Positive Patient Outcomes Advances in Anal Fistula Repair: Minimizing Risk for Incontinence An Interview With: Michael J. Stamos, MD Professor of Surgery Chief, Division of Colon and Rectal Surgery University of California at Irvine School of Medicine Irvine, California influence outcomes in single-center studies, including patient selection, peri-procedural management, and operator experience, the relative efficacy of these methods remains uncertain. In this summary, 2 surgeons describe a rational approach to patient selection for anal fistula plugs. Each surgeon details the advantages and limitations of a conservative approach. They both selectively employ anal fistula plugs as an alternative to fistulotomy with slightly different criteria. Background Elizabeth McConnell, MD Clinical Research Faculty Arizona State University Clinical Teaching Professor St. Joseph’s Hospital Owner, McConnell Colorectal Center and Arizona Outpatient Surgery Phoenix, Arizona Introduction Fistulotomy, although effective for repair of intersphincteric and low transsphincteric anal fistulae, poses a substantial risk for complications, particularly incontinence, in the treatment of high transsphincteric fistulae. Additionally, complex fistulae are not amenable to fistulotomy, and they include fistulae involving greater than 30% of the external sphincter, anterior fistulae in females, multitract fistulae, horseshoe fistulae, and patients who have pre-existing incontinence, local irradiation, or Crohn’s disease. In such fistulae, 2 commercially produced biodegradable plugs are among the options for conservative repair. The efficacy of conservative options, which also include placement of setons, use of fibrin glue, construction of an endorectal advancement flap, and the ligation of the intersphincteric fistula tract (LIFT) procedure, largely has been defined by case series, often at single centers. Due to the limited controlled studies and variables that 1 General SurgeryPublishing NEws December 2010 Copyright © 2012 McMahon Reliable data on the precise incidence of anal fistula in the United States are not available, but surgical centers recognize this condition as a common source of referral. In an epidemiologic study undertaken in Finland, the incidence over a 10-year period approached 10 per 100,000 with a concentration among adults in their 30s and 40s.1 Although anal fistulae can occur at any age, the mean age in the European study was 38.8 years. The incidence was about twice as common in men as in women (12.3 vs 5.6 per 100,000 cases).1 The pathophysiology of anal fistula and the reason for a peak incidence in young to middle-aged adults remains controversial, but infection in cryptoglandular spaces of the anal canal is a frequently cited hypothesis for the initiating event.2 The theory is that an abscess formed by infection in glands surrounding the anal canal progresses into formation of the fistulae that connect the muscular wall of the sphincter to the perianal skin. Although it is believed that all fistulae originate as abscesses, only a proportion of abscesses progress to fistulae.3 In the Parks Classification system, anal fistulae, defined by their position in relationto the anal sphincter, are described as transsphincteric, intersphincteric, suprasphincteric,or extrasphincteric.4 The most common presentation is intersphincFigure 1. The design of the GORE® teric, followed by transsphincteric. The BIO-A® Fistula Plug features bundled remaining 2 types are relatively uncomhollow tubes attached to a circular disk. mon. The position of the anal fistulahas The disk helps the plug stay in place, critical importance to the choice of therreducing the chance for extrusion of apy. High transsphincteric fistulae, which the plug. It also facilitates reproducible are defined by involvement of at least anchoring for dependable performance. one-third of the external anal sphincter the Science Behind Positive Patient Outcomes muscle as assessed by clinical examination or radiological imaging, are regarded as the most challenging.5 While fistulotomy is effective in 80% to 90% of primary fistulae, it poses a risk for complications and does not preclude recurrences.6 For high transsphincteric or other complex fistulae, the risk that incontinence will followfistulotomy is so great that most surgeons consider the procedure inappropriate.7 The range of reported continence disturbance after fistulotomy ranges from 0 to 64%.7-9 A cutting seton may also be used to perform a staged fistulotomy; however, incontinence resulting from this approach can be significant (2% to 63%).10 Alternative treatments have been pursued in high transsphincteric fistulae or complex fistulae, such as those with multiple channels. In patients with high transsphincteric or complex fistulae, fistulotomy is less attractive because of a need for significant injury of the sphincter muscle that can lead to incontinence, making more conservative measures a reasonable choice for preserving options.3 Although success rates may be no greater with conservative measures, there are numerous advantages when healing is achieved, including less risk for morbidity, the potential for lower cost, and faster recovery. The disadvantages of several conservative therapies include a high rate of failure. Some techniques, such as fibrin glue, that have produced fistula closure rates of less than 20% in some series are no longer widely used.11,12 Success with endorectal advancement flaps has been variable: A review of the literature from 1978 to 2008 shows efficacy rates from 36.6% to 98.5%, with reported incontinence ranging from 0 to 35%.13 The LIFT procedure is promising but relatively new and has not been well studied outside of centers that pioneered the technique.14-16 As a result, the efficacy in transsphincteric and complex fistulae, compared with other conservative techniques or fistulotomy, remains poorly defined. Anal fistula plugs also have been associated with variable success rates, but there are differences between the 2 available devices. The first commercially available anal plug in the United States was developed from lyophilized porcine intestinal submucosa (COOK® BIODESIGN™ SURGISIS® Fistula Plug, Cook Medical Inc., Bloomington, IN), which was created into a conical shape for insertion to the fistula tract. Although this plug, which was licensed by the FDA in 2005, was superior to fibrin glue for closure of high transsphincteric fistulae in a 25-patient, nonrandomized study,17 the limitations of fibrin glue made this efficacy difficult to interpret. Subsequent studies suggested that this device yields relatively low success rates in the complex and challenging fistulae for which it is most needed, falling as low as 13.9% in some series.18,19 The newer of the 2 anal fistula plugs, licensed by the FDA in 2009 (GORE® BIO-A® Fistula Plug, W. L. Gore & Associates, Inc., Flagstaff, AZ), is a 100% bioabsorbable, synthetic construction (polyglycolic acid:trimethylene carbonate) that employs a tubelike structure intended to provide a greater barrier to dislodgement (Figure 1). The scaffolding of the synthetic material allows cells to migrate into the matrix and tissue formation begins as the body gradually absorbs the material. As it is absorbed, the material is replaced with native tissue,20 predominantly type 1 collagen, in an approximately 1:1 ratio over time (Figure 2).21 In addition, the plug is engineered to conform to the tract and reduce the likelihood of plug dislodgement. Initial healing rates reported by 2 experts experienced with this device have been encouraging and suggest this is a useful tool when used selectively. Michael J. Stamos, MD: Current Application of Anal Fistula Plugs In the treatment of complex anal fistulae, therapy must always be individualized. Although the success rate with fistulotomy in uncomplicated fistulae may exceed 95%,6 neither surgery nor conservative measures achieve this type of success in fistulae that are complex (as defined by a high transsphincteric location, prior treatment failure, or the presence of multiple tracts). Once complex fistulae are drained—typically with seton placement— and infection has been controlled, it is reasonable to provide patients with treatment options that may include advancement flap surgery, anal plug placement or, in some cases, the LIFT procedure (Figure 3). The advantage of the anal fistula plug is that it preserves all other treatment options. In particular, flap surgery remains viable in the event success is not achieved. Although flap surgery has the potential for definitive repair, the risk for incontinence is substantial in difficult a) Human explant at 3 months (Milligan’s b) Human explant at 13.5 months cases. This encourages many patients to select trichrome, 10× magnification).21 (Milligan’s trichrome, 4× magnification).21 a fistula plug, which has become an attractive option since the Gore device was introduced, Figure 2. Bioabsorbable material degradation is visible as collagen (green) fills as an initial procedure. The previous plug, the the space. COOK® BIODESIGN™ SURGISIS® Fistula Plug, 2 General Surgery NEws December 2010 Supported and approved by Complex Anal Fistula Draining Station Anal Fistula Plug If fails If fails Repeat Plug LIFT If fails If fails Figure 3. Algorithm for complex anal fistula treatment. LIFT, ligation of the intersphincteric fistula tract Image courtesy of Michael J. Stamos, MD. Advancement Flap transsphincteric fistulae, the plug appears to pose a minimal risk for incontinence versus other conservative procedures, such as the endorectal advancement flap. Moreover, hospital length of stay (outpatient procedure) and recovery time are shorter relative to flap surgery. The synthetic plug is easily secured in place by suturing the disk into the anorectal mucosa and muscularis (Figure 4). Although Dr. Stamos does not employ a pocket flap to further reduce the risk for plug dislodgement, he noted that this might be useful in some cases. Patient selection and education are critical. Although the newer plug can be employed effectively to reduce the need for more invasive surgery and the risk for incontinence in many complex fistulae, surgeons need to prepare patients for potential unresolved fistula, as is known to occur with complex anal fistulae. When effective, the anal fistula plug is a relatively simple procedure with few technical demands that also preserves alternative treatment options. “In my experience success rates have been approximately 50%,23 which compares favorably to alternatives even though it is among the least invasive approaches,” said Dr. Stamos. Elizabeth McConnell, MD: Current Application of Anal Fistula Plugs For complex fistulae, the anal fistula plug can be an effective treatment once the fistula has matured, usually following a period in which a drainage seton has permitted the fistula to stab) The GORE® BIO-A® Fistula Plug can be a) The device is pulled into the tract until bilize. At this point, it becomes clearer which securely seated at the internal opening the disk lies flat and is well apposed to the approach might be most suitable. In cases when by covering it or by suturing the disk to anorectal mucosa. minimal division of the sphincter is involved, fisthe anorectal mucosa and muscularis, as tulotomy is effective with an acceptable risk for shown in this case. incontinence. In patients with a complex fistula for whom a conservative approach may be Figure 4. Securing the GORE® BIO-A® Fistula plug in the anorectal mucosa and more attractive to circumvent the risks associmuscularis. ated with surgery, the fistula plug often is an attractive choice. was not effective in well-designed studies. In a prospective study Due to a low rate of success, mainly resulting from dislodgement, of consecutive patients published 2 years after the plug was made Dr. McConnell discontinued use of COOK® BIODESIGN™ SURGISIS® available, the success rate was only 41%.22 “Dislodgement has Fistula Plug after an initial patient series. However,based on changes been a particularly common problem, and my success rates were in design and reports of improved outcomes with the GORE ® sufficientlydisappointing that I abandoned this procedure,” said BIO-A® Fistula Plug, she reintroduced this device into her treatment modality approximately 18 months ago. Since that time, Dr. Dr. Stamos. The design features of the GORE® BIO-A® Fistula Plug, particu- McConnellhas treated a total of 20 fistulae in 12 patients, with larly a structure that permits a tighter fit into the fistula, has revived a fistula placement success rate of 75% (15 of 20 fistulae) and a the viability of this option, which Dr. Stamos has been employ- patient success rate of 67% (8 of 12 patients) for patients followed ing routinely since these became commercially available. In high at least 12 months. These rates are equivalent to her experience General Surgery News December 2010 3 the Science Behind Positive Patient Outcomes with the LIFT procedure, but the fistula plug better preserves options in the event of failure. In many cases, it is appropriate to make a second attempt with the fistula plug. Although success on second attempts has been lower, at approximately 50% (2 successful fistulae in 4 repeat attempts), this rate of success remains substantial for a relatively noninvasive approach to a challenging problem. “In my experience with the fistula plug by Gore, patients often are uncomfortable during the initial 3 days after the procedure, which may be the result of an inflammatory reaction, but patients warned of this phenomenon usually are tolerant, and the pain typically resolves completely after this period,” said Dr. McConnell. In successful treatment, healing may be achieved within 60 days, although longer healing may be required and failure should not be declared until at least 4 months of follow-up. Dietary counseling, particularly an emphasis on high-fiber diets, is an essential part of efforts to increase healing and prevent recurrence. Not all patients with complex fistulae are candidates for anal fistula plugs even if they are not well suited for surgery. Dr. McConnell does not employ anal fistula plugs in women with anterior fistulae or in patients with diabetes with posterior fistulae, but her experience has provided much confidence for the use of the GORE® BIO‑A® Fistula Plug in routine care when employed selectively. “When these are effective, they allow patients to undergo a relatively simpleprocedure with a very low risk for complications and without eliminating other treatment options if success is not achieved,” said Dr. McConnell. Conclusion Complex anal fistulae pose a significant clinical challenge because not all of the variables that influence treatment success are fully understood. Although surgery may offer one of the most reliable approaches for the goal of fistula closure and healing, the associated risk for incontinence makes more conservative approaches preferable in complex cases. Of conservative options, the newer anal fistula plug is a relatively simple device, with an encouraging rate of healing relative to other conservative options. References 10. Whiteford MH, Kilkenny J 3rd, Hyman N, et al; Standards Practice Task Force; American Society of Colon and Rectal Surgeons. Practice parameters for the treatment of perianal abscess and fistula-in-ano (revised). Dis Colon Rectum. 2005;48(7): 1337-1342. 11. Buchanan GN, Bartram CI, Phillips RK, et al. Efficacyof fibrin sealant in the management of complex anal fistula: a prospective trial. Dis Colon Rectum. 2003;46(9): 1167-1174. 12. Sentovich SM. Fibrin glue for anal fistulas: long-term results. Dis Colon Rectum. 2003;46(4):498‑502. 13. Soltani A, Kaiser AM. Endorectal advancement flap for cryptoglandular or Crohn’s fistula-in-ano. Dis Colon Rectum. 2010;53(4):486-495. 14. Shanwani A, Nor AM, Amri N. Ligation of the Intersphincteric Fistula Tract (LIFT): A sphincter-saving technique for fistula-in-ano. Dis Colon Rectum. 2010;53(1):39-42. 15. Bleier J, Moloo H, Goldberg SM. Ligation of the intersphincteric fistula tract: an effective new technique for complex fistulas. Dis Colon Rectum. 2010;53(1):43-46. 16. Rojanasakul A. LIFT procedure: a simplified technique for fistula-in-ano. Tech Coloproctol. 2009;13(3):237-240. 17. Johnson EK, Gaw JU, Armstrong DN. Efficacy of anal fistula plug vs. fibrin glue in closure of anorectal fistulas. Dis Colon Rectum. 2006;49(3):371-376. 18. Ortiz H, Marzo J, Ciga MA, Oteiza F, Armendariz P, de Miguel M. Randomized clinical trial of anal fistula plug versus endorectal advancement flap for the treatment of high cryptoglandular fistula in ano. Br J Surg. 2009;96(6):608-612. 19. Safar B, Jobanputra S, Sands D, Weiss EG, Nogueras JJ, Wexner SD. Anal fistula plug: initial experience and outcomes. Dis Colon Rectum. 2009;52(2):248-252. 20. Morales-Conde S, Flores M, Fernandez V, Morales–Mendez S. Bioabsorbable vs. polypropylene plug for the “Mesh and Plug” inguinal hernia repair. Poster presented at the 9th Annual Meeting of the American Hernia Society; February 9-12, 2005; San Diego, CA. 21. W. L. Gore & Associates, Inc. 2006. Doerhoff, CR. Immunohistochemical Assessment of Collagen in an Explanted GORE Bioabsorbable Hernia Plug at 13.5 months. Flagstaff, AZ. 22. van Koperen PJ, D’Hoore A, Wolthuis AM, Bemelman WA, Slors JF. Anal fistula plug for closure of difficult anorectal fistula: a prospective study. Dis Colon Rectum. 2007;50(12):2168-2172. 23. Buchberg B, Masoomi H, Choi J, Bergman H, Mills S, Stamos MJ. A tale of two (anal fistula) plugs: is there a difference in short-term outcomes? The American Surgeon. 2010;76(10):1150-1153. DISCLAIMER: This article is designed to be a summary of information. While it is detailed, it is not an exhaustive clinical review. McMahon Publishing, W. L. Gore & Associates, Inc., and the authors neither affirm nor deny the accuracy of the information contained herein. No liability will be assumed for the use of the article, and the absence of typographical errors is not guaranteed. Readers are strongly urged to consult any relevant primary literature. Copyright © 2012, McMahon Publishing, 545 West 45th Street, New York, NY 10036. Printed in the USA. All rights reserved, including the right of reproduction, in whole or in part, in any form. Sainio P. Fistula-in-ano in a defined population. Incidence and epidemiological aspects. Ann Chir Gynaecol. 1984;73(4):219-224. 2. Parks AG. Pathogenesis and treatment of fistula-in-ano. Br Med J. 1961;1(5224): 463-469. 3. Hamalainen KP, Sainio AP. Incidence of fistulas after drainage of acute anorectal abscesses. Dis Colon Rectum. 1998;41(11):1357-1361; discussion 61-62. 4. Parks AG, Gordon PH, Hardcastle JD. A classification of fistula-in-ano. Br J Surg. 1976;63(1):1-12. 5. Wang JY, Garcia-Aguilar J, Sternberg JA, Abel ME, Varma MG. Treatment of transsphincteric anal fistulas: are fistula plugs an acceptable alternative? Dis Colon Rectum. 2009;52(4):692-697. 6. Knoefel WT, Hosch SB, Hoyer B, Izbicki JR. The initial approach to anorectal abscesses: fistulotomy is safe and reduces the chance of recurrences. Dig Surg. 2000;17(3):274-278. 7. 9. Van Tets WF, Kuijpers HC. Continence disorders after anal fistulotomy. Dis Colon Rectum. 1994;37(12):1194-1197. Lindsey I, Jones OM, Smilgin-Humphreys MM, et al. Patterns of fecal incontinence after anal surgery. Dis Colon Rectum. 2004;47(10):1643-1649. 4 General Surgery NEws December 2010 Gore products referenced within, if any, are used within their FDA approved/cleared indications. Gore does not have knowledge of the indications and FDA approval/ clearance status of non-Gore products. Gore makes no representations as to the surgical techniques, medical conditions or other factors that may be described in this article. The reader is advised to contact the manufacturer for current and accurate information. AQ0106-EN1 Scan icon to watch Dr. Stamos’ video on your iPhone, BlackBerry or Droid. Get the free mobile app at http:/ / gettag.mobi BB1057 1. 8. Omner A, Wenger FA, Rolfs T, Walz MK. Continence disorders after anal surgery— a relevantproblem? Int J Colorectal Dis. 2008:23(11):1023‑1031.
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