Practice Parameters for the Treatment of Perianal Abscess and Fistula-in-Ano (Revised)

Abstract

The American Society of Colon and Rectal Surgeons is dedicated to assuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Standards Committee is composed of Society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This Committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is accompanied by developing Clinical Practice Guidelines based on the best available evidence. These guidelines are inclusive, and not prescriptive. Their purpose is to provide information on which decisions can be made, rather than dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.

Full text

Parameters
Practice Parameters for the Treatment
of Perianal Abscess and
Fistula-in-Ano (Revised)
Prepared by
The Standards Practice Task Force
The American Society of Colon and Rectal Surgeons
Mark H. Whiteford, M.D., John Kilkenny III, M.D., Neil Hyman, M.D.,
W. Donald Buie, M.D., Jeffrey Cohen, M.D., Charles Orsay, M.D., Gary Dunn, M.D.,
W. Brian Perry, M.D., C. Neal Ellis, M.D., Jan Rakinic, M.D., Sharon Gregorcyk, M.D.,
Paul Shellito, M.D., Richard Nelson, M.D., Joe J. Tjandra, M.D.,
Graham Newstead, M.D.
The American Society of Colon and Rectal Surgeons is dedicated to assuring high-quality patient care by
advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and
anus. The Standards Committee is composed of Society members who are chosen because they have
demonstrated expertise in the specialty of colon and rectal surgery. This Committee was created to lead
international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is
accompanied by developing Clinical Practice Guidelines based on the best available evidence. These
guidelines are inclusive, and not prescriptive. Their purpose is to provide information on which decisions
can be made, rather than dictate a specific form of treatment. These guidelines are intended for the use of
all practitioners, health care workers, and patients who desire information about the management of the
conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines
should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably
directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific
procedure must be made by the physician in light of all of the circumstances presented by the individual
patient.
METHODOLOGY
These guidelines are built on the last set of The
American Society of Colon and Rectal Surgeons
(ASCRS) Practice Parameters for treatment of fistula-
in-ano published in 1996.
3,4
Pertinent information from
the published literature through December 2003 was
retrieved and reviewed. Organized searches of MED-
LINE and the Cochran Database of Systematic Re-
views were performed. Keywords included: abscess,
fistula, fistula-in-ano, anal, rectal, perianal, perianal,
rectovaginal, seton, and Crohn’s. Directed searches of
the embedded references from primary articles also
were accomplished.
Correspondence to: Neil Hyman, M.D., Fletcher Allen Health
Care, 111 Colchester Avenue, Fletcher 301 Burlington, Vermont
05401, e-mail: Neil.Hyman@vtmednet.org
Dis Colon Rectum 2005; 48: 1337–1342
DOI: 10.1007/s10350-005-0055-3
© The American Society of Colon and Rectal Surgeons
Published online: 17 May 2005
1337
Practice

PERIANAL ABSCESS
Treatment Recommendations
1. Guideline: A perianal abscess should be treated
in a timely fashion by incision and drainage. Level of
Evidence: Class IV; Grade of Recommendation: B.
Most perianal abscesses arise from the occluded duct
of an anal gland with subsequent bacterial over-
growth and abscess formation.
5
Lack of fluctuance
should not delay timely drainage. Treatment goals
should include incision and drainage of the abscess
and the prevention of an acute recurrence by prevent-
ing the premature closure of the incision. This can be
accomplished by an adequate incision or excision of
the overlying skin, inserting a drainage catheter, or
placement of a seton.
6,7
A seton often is used to con-
trol local sepsis before definitive repair of an anal
fistula. Although many perianal abscesses are readily
treated in an office setting, more complex infections
often require examination under anesthesia to ensure
adequate drainage. Serious infections, especially
those occurring in compromised hosts, may require
hospitalization.
2. Guideline: Antibiotics are an unnecessary addi-
tion to routine incision and drainage of uncompli-
cated perianal abscesses. Level of Evidence: Class II;
Grade of Recommendation: A. The addition of anti-
biotics to routine incision and drainage of cutaneous
abscesses does not improve healing times nor reduce
recurrences and is therefore not ordinarily indi-
cated.
8–10
These studies excluded patients with high-
risk conditions, such immunosuppression, diabetes,
extensive cellulitis, or prosthetic devices. In such situ-
ations, antibiotics should be considered.
In addition, the American Heart Association advises
preoperative antibiotics before incision and drainage
of infected tissue in patients with prosthetic cardiac
valves, previous bacterial endocarditis, complex con-
genital heart disease, surgically constructed systemic
pulmonary shunts or conduits, congenital cardiac
malformations, acquired valvular dysfunction (e.g.,
rheumatic heart disease), hypertrophic cardiomyopa-
thy, and mitral valve prolapse with valvular regurgi-
tation and/or thickened leaflets.
11
FISTULA-IN-ANO
Fistula-in-ano denotes the chronic phase of anorec-
tal sepsis and is characterized by chronic purulent
drainage or cyclical pain associated with abscess re-
accumulation followed by intermittent spontaneous
decompression. This is the natural history in up to 50
percent of perianal abscesses and is a result of per-
sistent anal sepsis and/or an epithelialized track. The
categorization of a fistula-in-ano is dependent on its
location relative to the anal sphincter muscles accord-
ing to Parks classification: intersphincteric, trans-
sphincteric, suprasphincteric, or extrasphincteric.
12
The term “complex” fistula is a modification of the
Parks classification, which describes fistulas whose
treatment poses a higher risk for impairment of con-
tinence. An anal fistula may be termed “complex”
when the track crosses >30 to 50 percent of the ex-
ternal sphincter (high-transsphincteric, suprasphinc-
teric, and extrasphincteric), is anterior in a female, has
multiple tracks, is recurrent, or the patient has preex-
isting incontinence, local irradiation, or Crohn’s dis-
ease.
13–15
Levels of Evidence and Grades of Recommendation
1,2
Level Source of Evidence
I Meta-analysis of multiple well-designed, controlled studies; randomized trials with low false-positive
and low false-negative errors (high-power)
II At least one well-designed experimental study; randomized trials with high false-positive or high
false-negative errors or both (low-power)
III Well-designed, quasi-experimental studies, such as nonrandomized, controlled, single-group,
preoperative-postoperative comparison, cohort, time, or matched case-control series.
IV Well-designed, nonexperimental studies, such as comparative and correlational descriptive and case
studies
V Case reports and clinical examples
Grade Grade of recommendation
A Evidence of Type I or consistent findings from multiple studies of type II, III, or IV
B Evidence of Type II, III, or IV and generally consistent findings
C Evidence of Type II, III, or IV but inconsistent findings
D Little or no systematic empirical evidence
1338 WHITEFORD ET AL Dis Colon Rectum, July 2005

The goals in the treatment of fistula-in-ano are 1) to
eliminate the septic foci and any associated epitheli-
alized tracks, and 2) to do so with the least amount of
functional derangement. To initiate the most appro-
priate treatment, the etiology should be defined. This
is usually cryptoglandular infection but may be re-
lated to Crohn’s disease, trauma, radiation, or malig-
nancy.
There is no single technique appropriate for the
treatment of all fistulas-in-ano and, therefore, treat-
ment must be directed by the surgeon’s experience
and judgment. One should keep in mind the progres-
sive tradeoff between the extent of operative sphinc-
ter division, postoperative healing rates, and func-
tional detriment.
14
Healing rates can be adversely
affected by the presence of Crohn’s disease or previ-
ous radiation therapy. Postoperative functional out-
comes can be adversely affected by preexisting incon-
tinence, previous mechanical sphincter injury, the
amount of sphincter at risk, an anterior location in
females, stool consistency, and the patient’s tolerance
of potential imperfections in their continence.
Treatment of a Simple Fistula-in-Ano
1. Simple anal fistulas may be treated by fistu-
lotomy. Level of Evidence: Class II; Grade of Recom-
mendation: B. The fundamentals of fistulotomy in-
clude defining the entire fistula track from internal
opening to external opening with identification and
obliteration of primary and secondary tracks. Fistu-
lotomy is preferable to fistulectomy. Despite similar
recurrence rates, the latter results in larger wounds
with a longer healing time and higher rates of incon-
tinence.
16
Studies report great variability in the results
of fistula surgery because of heterogeneous popula-
tions, differing definitions of fistula types and func-
tional disorders, and length of follow-up. The recur-
rence rate for fistulotomy is generally between 2 and
9 percent with a functional impairment generally be-
tween 0 and 17 percent.
17,18
Any functional derange-
ment will tend to improve for up to two years after
surgery. One randomized, controlled trial reported
faster healing and better preservation of anal squeeze
pressures when anal fistulotomy wounds were mar-
supialized compared with simply laid open.
19
2. Simple anal fistulas may be treated with track
debridement and fibrin glue injection. Level of Evi-
dence: Class IV; Grade of Recommendation: B. Fibrin
glue is an easy and repeatable treatment for fistula-
in-ano with relatively few side effects and little to no
risk of fecal incontinence. Successful healing rates
from 60 to 70 percent can be achieved.
20–26
Risk fac-
tors for failure include Crohn’s disease, rectovaginal
fistula, human immunodeficiency virus, and short fis-
tula length.
Treatment of a Complex Fistula-in-Ano
The anatomy of most complex fistulas can be de-
fined in the operating room without supplemental im-
aging studies. However, radiographic evaluation may
be a beneficial adjunct to identify occult internal
openings, secondary tracts or abscesses, or to help
delineate the fistula’s relationship to the sphincter
complex. Magnetic resonance imaging and endorectal
ultrasound with or without hydrogen peroxide injec-
tion are the studies of choice when radiologic assess-
ment is deemed necessary.
27–29
1. Guideline: Complex anal fistulas may be treated
with debridement and fibrin glue injection. Level of
Evidence: IV; Grade: B. As with simple fistula-in-ano,
fibrin glue is an easy, repeatable treatment for a com-
plex fistula-in-ano. Using this technique, healing rates
from 14 to 60 percent have been achieved in small
studies.
20–22
Incontinence rates, however, although
theoretically low, have not generally been reported.
2. Guideline: Complex anal fistulas may be treated
with endorectal advancement flap closure. Level of
Evidence: IV; Grade: B. The use of an endorectal ad-
vancement flap is an attractive modality for the treat-
ment of a complex fistula-in-ano. It obliterates the
septic focus and closes the internal opening, does not
divide the sphincter, is repeatable, has a smaller
wound, and can be combined with overlapping
sphincter reconstruction for anterior fistulas. Success-
ful healing has been demonstrated in 55 to 98 percent
of patients.
14,15,30–35
Although the sphincter mecha-
nism is not divided during the construction of an en-
dorectal advancement flap, minor incontinence has
been reported in up to 31 percent of the patients and
major incontinence in up to 12 percent.
14,30,34,36,37
Predictors of poor outcome include undrained sepsis,
cancer or radiation etiology, rectovaginal fistula diam-
eter >2.5 cm, fistula present fewer than 6 weeks, and
active Crohn’s proctitis.
15,34,38
3. Guideline: Complex fistulas may be treated by
the use of a seton and/or staged fistulotomy: Level of
Evidence: IV; Grade: B. A seton is a flexible foreign
body (e.g., suture material, silastic vessel loop) that is
1339PERIANAL ABSCESS AND FISTULA-IN-ANOVol. 48, No. 7

placed through the fistula track and secured to itself.
Setons may be used to induce perisphincteric fibrosis
along the fistula track so that when the fistulotomy is
eventually performed, or the seton gradually tight-
ened, the muscular defect and amount of inconti-
nence is limited.
39,40
A seton may also be utilized to
facilitate staged fistulotomy. The seton is used to mark
the external sphincter for later division after the sub-
cutaneous components have healed. Although these
two techniques have low recurrence rates (0–8 per-
cent), the rates for minor (34–63 percent) and major
incontinence (2–26 percent) are significant.
39–45
Treatment of Fistula-in-Ano With
Crohn’s Disease
The clinical course of perianal Crohn’s disease is
unpredictable; complete and permanent remission is
rare. The recurrent nature of the disease, with its at-
tendant potential for chronic diarrhea, places a pre-
mium on conservative, sphincter-sparing manage-
ment. In addition, aggressive surgery may lead to
poor healing and impaired continence, which may
require a stoma.
46,47
Management of anorectal
Crohn’s disease may be further complicated by con-
current active colorectal and/or small-bowel disease.
Desirable outcomes should not focus exclusively on
complete healing and continence but should also in-
clude patient satisfaction, reduction in the number of
septic events, and minimization of proctectomy rates.
Medical management of active Crohn’s disease should
supplement the surgical management. Twelve to 39
percent of these patients will eventually undergo
proctectomy for progressive intestinal disease or in-
tractable perianal disease.
48–51
1. Guideline: Asymptomatic Crohn’s fistulas need
not be treated. Level of Evidence: IV; Grade: B.
Asymptomatic Crohn’s fistulas may remain dormant
and require no intervention. These patients, therefore,
need not be subjected to the morbidity of operative
intervention.
49,51–53
2. Guideline: Simple, low Crohn’s fistulas may be
treated by fistulotomy. Level of Evidence: IV; Grade: B.
Healing rates after fistulotomy or intersphincteric and
low transsphincteric Crohn’s fistulas range from 62 to
100% with reported minor incontinence rates of 0 to
12%.
46,49–52,54–57
These wounds may take up to three
to six months to heal.
48
3. Guideline: Complex Crohn’s fistulas may be well
palliated with long-term draining setons. Level of Evi-
dence: IV; Grade: B. The goal of a long-term loose
(draining) seton for Crohn’s fistulas is to reduce the
number of subsequent septic events by providing
continuous drainage and preventing closure of the
external skin opening. This goal can be achieved in 48
to 100% of such patients. Recurrent sepsis is seen
approximately one-third of the time.
41,46,51,53,58
4. Guideline: Complex Crohn’s fistulas may be
treated with advancement flap closure if the rectal
mucosa is grossly normal. Level of Evidence: IV;
Grade: B. Endorectal or anodermal advancement
flaps also can be used in patients with complex fistu-
las from Crohn’s disease. Active proctitis is considered
a contraindication. Short-term success (generally 50–
75%) is lower in patients with Crohn’s disease and
continues to diminish with longer follow-up, demon-
strating the chronic relapsing nature of this disease.
Short-term success rates for rectovaginal fistulas asso-
ciated with Crohn’s disease are even lower at 40 to
50%.
14,31,32,48–50,,52–63
The practice parameters set forth in this document have been developed from sources believed to be reliable. The
American Society of Colon and Rectal Surgeons makes no warranty, guaranty, or representation whatsoever as
to the absolute validity or sufficiency of any parameter included in this document, and the Society assumes no
responsibility for the use or misuse of the material contained.
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