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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_894_Библиотеки_им_академика_М_И_Перельмана.pdf
10 Anorectal Abscess and Fistula in Ano
173
a
c
b
d
Fig. 10.9 Classication of stula-in-ano. (a) Intersphincteric. (b) Transsphincteric. (c) Suprasphincteric. (d)
Extrasphincteric
tract may also occur in this variety and result in a
horseshoe extension. Extrasphincteric Fistula-inano pass from the rectum above the levators and
through them to the perianal skin via the ischiorectal space (Fig.10.9d). This stula may result
from foreign body penetration of the rectum with
drainage through the levators, from penetrating
injury to the perineum, or from Crohn’s disease
Simple anal stulae have none of these complex features and generally include intersphincteric and low transphincteric stula that involve
<30% of the sphincter complex. Given the attenuated nature of the anterior sphincter complex
in women, stulae in this location deserve special consideration and may also be considered
complex.
or carcinoma or its treatment. However, the most
common cause may be iatrogenic secondary to
vigorous probing during stula surgery.
Evaluation
Fistula-in-ano may also be classied as “simple” or “complex”. Complex anal stula include
transphincteric stula that involve greater than
30% of the external sphincter, suprasphincteric,
extrasphincteric, or horseshoe stula, and anal
stula associated with inammatory bowel disease, radiation, malignancy, preexisting fecal
incontinence, or chronic diarrhea [38, 87–91].
Symptoms
A patient with a stula-in-ano will often recount
a history of an abscess that has been drained
either surgically or spontaneously. Patients may
complain of drainage, pain with defecation,
bleeding due to the presence of granulation tissue
at the internal opening, swelling or decrease in
174
J. D. Vogel and C.-A. Vasilevsky
pain with drainage. Additional bowel symptoms
may be present when the stula is secondary to
proctocolitis, Crohn’s disease, actinomycosis or
anorectal carcinoma [92].
Physical Examination
The external or secondary opening may be seen as
an elevation of granulation tissue discharging pus.
This may be elicited on digital rectal examination.
In most cases, the internal or primary opening is
not apparent. The number of external openings
and their location may be helpful in identifying
the primary opening. According to Goodsall’s
rule (Fig.10.10), an opening seen posterior to a
line drawn transversely across the perineum will
originate from an internal opening in the posterior
midline. An anterior external opening will originate in the nearest crypt. Generally, the greater
the distance from the anal margin, the greater the
probability of a complicated upward extension.
Cirocco found that Goodsall’s rule was accurate
in describing the course of anal stulas with a
posterior external opening [93]. It was inaccurate
in patients with anterior external openings since
71% of these stulas tracked to a midline anterior primary opening. This was especially true in
women in whom stulas with anterior external
openings tracked in a radial fashion in only 31%.
curved tracts
transverse line
straight tracts
Fig. 10.10 Goodsall’s rule
3cm
e
x
c
e
p
t
i
o
n
Digital rectal examination may reveal an indurated cord-like structure beneath the skin in the
direction of the internal opening with asymmetry
between right and left sides. Internal openings may
be felt as indurated nodules or pits leading to an
indurated tract. Posterior or lateral induration may
be palpable indicating stulas deep in the postanal
space or horseshoe stulas. Bidigital rectal examination will dene the relationship of the tract to
the sphincter muscles and provides information as
to preoperative sphincter tone, bulk and voluntary
squeeze pressure which need to be assessed preoperatively because of a possible risk of incontinence with sphincter division. Anoproctoscopy
should be done prior to operation in an attempt
to identify the primary opening. Sigmoidoscopy,
colonoscopy, and CT, MR, or ultrasound imaging should be considered in patients who have
symptoms suggestive of inammatory bowel
disease and in patients with multiple or recurrent
stulas. Although anal manometry is not generally required, it may be useful as an adjunct to
planning the operative approach in a women with
previous obstetric trauma, in an elderly patient,
a patient with Crohn’s disease or AIDS, or in a
patient with a recurrent stula [94].
Imaging
Simple stula-in-ano generally do not require
diagnostic imaging to guide treatment.
Alternatively, ultrasound, MRI, or stulography,
has proven useful in the assessment of occult anorectal complex or, in patients with Crohn’s disease, and in patients with recurrent stulas who
have undergone prior stula surgery [24–27, 95].
In a study of 54 patients with perianal Crohn’s
disease in which MRI and operative/clinical ndings were compared, all of the abscesses and 82%
of the stulas were correctly identied by MRI
[96]. In another 2014 study, MRI had a positivepredictive value (PPV) of 93% and a negativepredictive value of 90% for anorectal abscess and
a sensitivity of over 90% for stula-in-ano [29].
Representative studies of endoanal ultrasound
(EUS), in 2 or 3-dimesions, with or without peroxide enhancement, indicate that this imaging
modality is also useful in the diagnosis and classication of anorectal abscess and stula-in-ano
10 Anorectal Abscess and Fistula in Ano
175
with concordance with operative ndings in
73–100% of cases (Fig. 10.11) [30–33, 97].
Transperineal ultrasound (TPUS), a non-invasive
alternative to EUS, has been shown to accurately
identify the presence of in anorectal abscess and
stula [98–101].
In 2004, Buchanan performed a comparison of
limited clinical examination (awake, no probing),
EUS, and MRI in patients with stula-in-ano
and determined that these modalities accurately
classied the stula in 61%, 81%, and 90% of
patients, respectively [30]. A meta-analysis of
MRI and EUS for the assessment of stula-inano indicated that the sensitivity of MRI and
EUS were 87% and 87% and their specicity
were 69% and 43%, respectively [102].
Fig. 10.11 Anal
endosonogram. (a)
Longitudinal ultrasound
image of the medial left
buttock; *denotes air in
the anus; +denotes a
hypoechoic perianal
stula extending to the
skin surface caudad to
anus. (b) Horseshoe
abscess. *Presence of
horseshoe abscess
around the anal canal
a
b
176
J. D. Vogel and C.-A. Vasilevsky
Fistulography, contrast injection of the stula
under uoroscopy, may also be an effective means
of studying an anal stula with concordance with
operative ndings demonstrated in 89% of cases
[103]. In a recent study, stulography accurately
identied the primary stula tract, internal opening, secondary tracts, and associated abscess in
100%, 74%, 92%, and 88% of patients, respectively [32]. Finally, the added value of combining
diagnostic modalities to enhance the accuracy of
anal stula assessment was exemplied in a 2001
study of 34 patients with perianal Crohn’s disease in which EUS, MRI, and exam under anesthesia were accurate in 91%, 87%, and 91% of
patients, respectively, whereas 100% accuracy
was achieved with the combination of any two
techniques [26].
Treatment
General Principles
The principles of stula surgery are to eliminate the stula, prevent recurrence, and preserve
sphincter function. Success is usually determined
by identication of the primary opening and
dividing the least amount of muscle possible.
Dening the anatomy of the stula tract may be
facilitated by inspection and palpation, passage
of a probe or probes from the external opening to
the internal opening or vice-versa injection of a
dye such as dilute solution of methylene blue or
hydrogen peroxide and noting their appearance
at the dentate line. Cut through the skin and subcutaneous fat overlying the tract and lateral to the
sphincter complex and then following the tract
medially [92]. In addition, attention to preoperative imaging studies, such as with MR, have been
shown to complement the examination ndings
and result in improved outcomes of anal stula
surgery [30].
Operative Management
Fistulotomy
Fistulotomy is an effective and appropriate treatment for most simple anal stula and results in
healing in over 90% of patients [85, 86, 104,
105]. Fistulotomy failures have been associated
with complex types of stula, failure to identify
the internal opening, and Crohn’s disease [105,
106]. Recent, prospective multicenter studies
indicate that when stulotomy is used for simple
(low) anal stula, in properly selected patients,
the risk of fecal incontinence is minimal or none
[85, 86, 104]. Risk factors for post-operative
anal sphincter dysfunction include pre-operative
incontinence, recurrent disease, female gender,
complex stulas, and prior stula or anorectal surgery [105, 107–109]. Interventions other
than stulotomy are generally recommended in
patients with anal stula and these risk factors.
Preparation for stulotomy surgery is minimal and may include an enema cleansing of
the distal colon and rectum immediately before
the operation. Fistulotomy is performed with
the patient positioned in the prone jackknife or
high lithotomy position following induction of a
regional anesthetic. Local anesthetic (e.g. bupivacaine with epinephrine) is injected along the
stula tract. Digital rectal examination and anoproctoscopy are performed. A probe is inserted
from the external opening along the tract to the
internal opening at the dentate line. The amount
of sphincter muscle overlying the stula tract is
assessed. If, in fact, less than one-third of the
sphincter will divided with a stulotomy, the
tissue overlying the probe is incised and the
granulation tissue curetted and sent for pathologic evaluation. A gentle probe is used to identify any high blind tracts or extensions, which
are unroofed, if found. If desired, the wound
may be marsupialized on either edge by sewing
the edges of the incision to the tract with a running locked absorbable suture. Marsupialization
of the wound edges after stulotomy has been
associated with less post-operative bleeding and accelerated wound healing [110, 111].
Marsupialization may also reduce the need for
post-operative analgesics [112]. There is no need
to insert packing if an adequate unroong has
been accomplished (Fig. 10.12a–c). In recent,
large studies, perioperative complications of stulotomy occurred in 25–9% of patients, most
often limited to minor infection, urinary retention, or bleeding [85, 86, 104].
10 Anorectal Abscess and Fistula in Ano
177
a
b
c
Fig. 10.12 Anal stulotomy. (a) Insertion of probe and
incision of tissue overlying probe. (b) Curettage of granulation tissue. (c) Marsupialization of wound edges
The reported incidence of fecal incontinence
after stulotomy is quite variable, from very
few patients to as many as 80% and depends on
many factors including baseline anal sphincter
function, prior anorectal surgeries, stula type,
and amount of sphincter muscle that is divided
[49, 85, 86, 104, 105, 107, 109, 113]. In 2014,
the results of a 2014, multicenter, retrospective
study, that included 537 patients with a “low perineal stula” (less than one-third of the sphincter
complex involved), who underwent stulotomy,
reported major post-procedure fecal incontinence
in 28% of patients [113]. On the contrary, recent
prospective multicenter studies indicate that when
stulotomy is used for simple (low) anal stula, in
properly selected patients, the risk of fecal incontinence is minimal or none [85, 86, 104].
Staged Fistulotomy
Staged stulotomy involves the use of a draining or cutting seton (e.g. silk suture, silastic vessel loop) to gradually divide the stula tract is an
alternative to one-stage stulotomy that may also
be considered (Fig. 10.13). This technique was
used in a recently reported series of 200 patients
in whom a suture seton was tightened every
6–8 weeks, in preparation for a supercial or
“controlled” stulotomy [114]. Healing occurred
in 94% of patients with only minor disturbances
in anal sphincter function in 4% of patients.
Additional, recent retrospective studies of cutting setons for transphincteric or other complex
cryptoglandular stula have also demonstrated
stula healing in over 90% of patients and preservation of anal sphincter function in the majority of patients [115, 116]. Horseshoe abscess
and stulae that arise from them are well treated
with the staged stulotomy technique. Treatment
consists of identication of the internal opening
and proper drainage of the postanal space as was
previously described. The horseshoe extensions
are enlarged for counter-drainage and the granulation tissue is curetted. The Hanley procedure,
rst described in 1965, is a technique for draining
the deep post-anal space via major stulotomy
with additional incisions into the ischiorectal
spaces as needed to completely drain the abscess
[40]. While this procedure has proven effective
in the treatment of the horseshoe abscess, it is
178
ab
cd
Fig. 10.13 Anal seton
J. D. Vogel and C.-A. Vasilevsky
debilitating, and comprehensive assessment of its
impact on long-term anal sphincter function were
not included in the larger reported series [17, 39].
A modied Hanley technique, in which a partial
sphincterotomy is combined with a seton that is
incrementally tightened, is a less destructive but
similarly effective means of horseshoe abscess
resolution with preservation of anal sphincter
function [17, 41, 42].
Endoanal Advancement Flap
Endoanal advancement ap (Fig. 10.14a–d) is a
sphincter-sparing technique that consists of curettage of the stula tract, suture closure of the internal
opening, and mobilization of a segment of proxi-
Fig. 10.14 Endorectal advancement ap, (a) Transphincteric stula-in-ano. (b) Enlargement of external opening. (c)
Flap of muscle and muscle is mobilized. (d) Flap is advanced, the distal tip is removed, and the ap is sutured in place
10 Anorectal Abscess and Fistula in Ano
179
mal healthy anorectal mucosa, submucosa, and
muscle to cover the site. Preoperative mechanical
bowel preparation is usually performed. Patients
are positioned in the lithotomy or prone-jackknife
position depending on the location of the stula.
Perioperative prophylactic broad-spectrum antibiotics are used. With endoanal ap creation, the aim
is to create a well-perfused, tension-free ap that
covers the closed internal opening. Width of the
ap base two to three times greater than the width
of the ap apex has been recommended to ensure
adequacy of ap perfusion [117]. It is the preference of one of the editors (SDW) to perform an
elliptical sliding ap rather than incising the sides
of the ap. Postoperative antibiotic use and dietary
and activity restrictions aimed at improving healing
are advocated by some surgeons but not by others
without good evidence to support either approach
[118–120]. Reports indicate healing in 66–87%
after initial endoanal advancement ap for cryptogalndular stula [108, 118, 119, 121–123]. Among
those patients with recurrence, successful healing
may be achieved with repeat advancement ap procedures [118]. Factors associated with failed repair
include prior radiation, underlying Crohn’s disease,
active proctitis, rectovaginal stula, malignancy,
obesity, and the number of prior attempted repairs
[88, 105, 120, 122, 124–127]. Complications of
endoanal advancement ap, such as ap disruption
or urinary retention, are infrequently reported and
may be expected to occur in 3–12% of patients [118,
121, 128]. Although the sphincter is not divided per
se during ap formation, internal sphincter bers
may be included in the ap and mild to moderate
incontinence is reported in the range of 0–35% of
patients, with an average incidence of 12% in a
2010 systematic review of 35 studies [123]. One of
the editors (SDW) prefers an elliptical ap without
corners (Fig.10.15).
Ligation oftheIntersphincteric
Tract (LIFT) Procedure
The ligation of the intersphincteric stula tract
(LIFT) procedure is a sphincter-preserving technique that is used mainly for the treatment of
trans-sphincteric stula-in-ano [129]. With this
procedure, eradication of the stula is achieved
without division of the anal sphincter muscle. A
draining seton may be used before the LIFT procedure to promote brosis of the tract which may
facilitate the procedure but has not been shown
to enhance its success [130]. Preparation for the
LIFT procedure typically includes enema cleansing of the rectum in the immediate preoperative
period. Prone jack-knife or lithotomy positioning
is used. If a seton is present it is removed. The
anatomy of the stula is evaluated by anoscopy,
injection of water or dilute hydrogen peroxide
into the external opening, or by gentle probing of
the tract via the external opening. When the LIFT
procedure is judged to be appropriate, a 1.5–2cm
incision is made in the skin covering the intersphincteric grove. The internal and external anal
sphincters are separated to expose the intersphincteric portion of the stula tract. At this point, the
tract may be encircled with a right-angle clamp
and ligated alongside the internal and external anal sphincters or simply divided and then
suture ligated against the internal and external
anal sphincter (Fig. 10.16) [129]. Rojanasakul,
the LIFT procedure pioneer, noted that closure of
the stula tract at the lateral edge of the internal
anal sphincter, close to the internal opening of the
stula tract, is the “key to success” of this procedure [131]. The portion of the stula tract lateral
to the external anal sphincter is then “cored out”
or curetted. The external skin opening is left open
to drain. The defect in the intersphincteric groove
is loosely closed with ne absorbable sutures.
Complications of the LIFT procedure are uncommon with reported incidence in the range of
0–5% of patients [121, 132, 133]. Postoperative
care included 1–2weeks of broad-spectrum oral
antibiotics, stool softeners, and frequent watercleansing of the operative site [117, 131–133].
Meta-analyses of published data report that the
standard or “classic” LIFT has resulted in stula
healing in 61–94% of patients, with little morbidity, a healing time of 4–8weeks, and only rare
alterations in fecal continence [130, 134–137].
Modications to the LIFT procedure that include
omission of stula tract division, excision of the
lateral aspect of the tract, and the combined use
of a seton, stula plug, or biologic mesh interposition have also been described with limited data
indicating successful healing and preservation of
180
bc
fg
J. D. Vogel and C.-A. Vasilevsky
a
Fistula tract
Incision
Dentate line
Retractor
Posterior
Anterior
d e
Fig. 10.15 (a–g) Endorectal advancement ap tech-
nique. With permission from Maron DJ, Wexner SD.
Fissure-In-Ano and Anal Stenosis. In: Beck DE, Wexner
SD, Rafferty JF. Gordon and Nivatvongs’ Principles and
Practice of Surgery for the Colon, Rectum, and Anus, 4th
Ed. Thieme, New York, 2019 (in press)
10 Anorectal Abscess and Fistula in Ano
181
Fig. 10.16 Ligation
of intersphincteric
Tract (LIFT) . (a)
Incision in the
intersphincteric
groove to expose
stula tract containing
a exible probe. (b)
Tract is ligated
a
b
182
anal sphincter function both on par with the classic LIFT [134–138]. The LIFT procedure may be
used for both simple and complex transphincteric
stulae. A recent, prospective, multicenter study of
anal stula treatment included a total of 43 LIFT
procedures with healing rate of 79% and an overall
improvement in anal sphincter functional scores.
Among the 17 patients with a simple/low anal stula, 82% were healed at 3months follow-up [85].
Interestingly, the post-LIFT procedure fecal incontinence severity scores improved in Hall’s study.
Fistula tract length >3cm, previous procedures to
eradicate the stula, and obesity have each been
associated with LIFT failure [132, 134].
Anal Fistula Plug
The anal stula plug is an acellular collagen
matrix or a non-woven web of polyglycolic
acid:trimethylene carbonate (PGA:TMC) bers
used to close the primary internal anal opening and
to provide a scaffold for native tissue in-growth
that will obliterate the stula tract. Although early
data demonstrated 70–100% success with the plug
in low-lying stulas [139, 140], more recent outcomes in complex disease have been less promising with healing rates under 50% [141–145].
In preparation for the anal stula plug procedure, a draining seton may be used to facilitate
resolution of associated infection and to otherwise prepare the tract for plug insertion [146,
147]. Mechanical bowel preparation and peri-
operative prophylactic antibiotics are generally
recommended [139, 145, 147]. The procedure is
performed in the lithotomy, prone jack-knife, or
left lateral position. As a rst step, hydrogen peroxide or saline irrigation and/or curettage of the
stula tract is typically performed. The plug is
then inserted into the internal opening and pulled
through the tract with a suture until it is snug
(Fig.10.17). The plug is then trimmed, secured
to the internal anal sphincter with an absorbable
suture, and loosely sutured to the skin at the external opening without closing the external opening.
Post-procedural protocols are variable but in general include limited activity for several days [139,
145, 147]. In a recent, prospective multicenter
trial, with 93 patients, infection at the plug site
occurred in 12%, plug extrusion in 14%, healing
J. D. Vogel and C.-A. Vasilevsky
Fig. 10.17 Fistula plug
at 12months in 49%, and decrease anal sphincter
function in 11% of patients, respectively [148].
Reasons for early failure are typically sepsis or
plug dislodgement, and failure is more common in patients with Crohn’s disease, anovaginal stula, recurrent stula, or active smoking.
Individual studies have reported similar rates of
post-plug insertion complications [145, 146].
Fibrin Glue
Fibrin glue is another sphincter-preserving technique that has been used with variable success
in the treatment of stula-in-ano. In preparation
for this procedure, a mechanical bowel preparation and prophylactic antibiotics are commonly
administered [91, 149, 150]. The stula tract is
irrigated with saline or hydrogen peroxide and
may be curetted prior to glue instillation. An
angiocath is used to ll the stula tract with
2–5 mL of commercially available brin glue
solution (Fig. 10.18). After waiting a few minutes for the glue to harden it is trimmed at the
internal and external openings. Patients are typically discharged after the procedure with recommendations for light activity for several days.
Complications of brin glue therapy may occur
in as many as 50% of patients, but are most often
of mild severity and self-limited [91]. A tract