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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1408_Библиотеки_им_академика_М_И_Перельмана
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differentiate between supralevator and infralevator abscesses.17In IBD, CT can help to
delineate fistulas and abscesses from isolated rectal inflammation in patients with Crohn’s
disease.
24
Thin-slice spiral multiplanar CT scan is useful when MRI is not available or con-
traindicated (such as in claustrophobia).
25
However, a limitation occurs when the external
opening cannot be cannulated for contrast injection.
34
Also, the poor resolution of the soft
tissue makes it difficult to distinguish between the fistula tract, fibrotic material, and
sphincter muscle.
8,34
MRI with or without an endoanal coil is the gold standard for imaging the ARF.
8,17
The
accuracy was 90% for mapping fistula tract and identifying the internal opening.
17,24,25
It
can demonstrate the tract angulation related to the internal opening.
2
The anal sphincter
muscle, levator ani, and the tract branching are clearly demonstrated, therefore supralevator and infralevator abscesses can be differentiated.
8
The sensitivity and specificity of
MRI vs EAUS was 0.87 vs 0.87 and 0.69 vs 0.43, respectively.
26
MRI is pain free, nonoperator
dependent, and is preferred to EAUS when the lesion is far from the anus.
26
However, the
high cost and lack of availability may limit its usage.
23,25,26
Preoperative imaging assists the surgeon in planning, counseling, and selecting the
appropriate procedure.
2
In patients who may require sphincter division, preoperative
anorectal manometry can predict postoperative anal function
17
and allow preoperative
planning. The choice of investigation depends on the patient’s condition, availability of
facilities, cost, and the physician’s personal experience.
7.5 Treatment
The primary goal of ARA treatment is to drain the septic foci.
1
An immediate operative trial
to prevent future recurrence or fistula formation may not always be appropriate. Primary
fistulotomy without careful evaluation of the etiology and the anal sphincter complex may
lead to impaired continence without a cure for the ARA.
17
The principal goal of treatment
of ARF is to eradicate infection, eradicate the fistula tract, if possible, and decreased the
risk of recurrence while preserving anal sphin cter integrity and continence.
1,3
7.5.1 Treatment of an ARA
An ARA should be adequately drained in a timely manner.
23,24
Delayed or inadequate
treatment may lead to extensive life-threatening suppuration, tissue necrosis, and septicemia.
24
Incision and drainage can be performed under local anesthesia and should be as
close as possible to the anal verge
17,24
to minimize the length of the potential fistula.
16,35,36
With an adequate sized elliptical incision postoperative wound packing is not necessary
and should be avoided, as it may lead to pain and delayed healing.
24,35
Alternatively,
an abscess can be drained with a small tube via a stab incision and this can be
left in situ until drainage stops (3–10 days).
24,35
If the abscess is complex, drainage
should be performed in the operating room under sedation or regional or general anesthesia.
17
An intersphincteric abscess can be drained into the anal canal via internal
88 ANORECTAL DISORDERS
sphincterotomy.35A supralevator abscess that has originated from the upward extension
of the intersphincteric abscess may be drained into the rectum or via the transanal insertion of a drain.
35
An ischiorectal abscess with or witho ut supralevator extensions should
be drained through the perianal skin.
35
In the presence of a horseshoe abscess, a contralateral incision over the perianal skin overlying the ischiorectal fossa should also be made
to allow adequate drainage from both sides.
17
If the internal opening is identified, insertion of a seton through the fistula tract allows drainage and facilitates the second-stage of
the procedure, which may be performed 8weeks later.
17
A modified Hanley technique,
which is a partial sphincterotomy combined with seton, can be used to resolve a horseshoe abscess while minimizing the risk to analsphincter function.
35
A primary fistulotomy for simple fistula that has an identified internal opening should
be used with caution to avoid iatrogenic damage to anal sphincter.
17,35
In the first occurrence group, the recurrence rate was reduced by 83% (relative risk 0.17, P < 0.001) but a
high risk of fecal incontinence to flatus and soiling was seen (relative risk 2.46,
P ¼ 0.140).
37
Postoperative fecal incontinence has been reported as high as 44%.
17,35
The overall recurrence rate after ARA drainage ranges from 3% to 44%.35A fistula developed in 37% of patients and 10% developed a recurrent abscess.
38
Being female and suf-
fering from a horseshoe abscess were associated with higher recurrence rates.
35,38
The
surgeon should weigh the possible decreased recurrence rate with the potentially
increased risk of continence disturbance.
24
Antibiotic therapy is unnecessary in an uncomplicated ARA undergoing drai nage.
17,35
It should be considered in patients with cellulitis, concomitant systemic disease,
HIV, underlying immunosuppression, or atypical anorectal infection.
17,24,35
Preoperative
antibiotics before incision and drainage should be given in patients with previous bacterial endocarditis, prosthetic valve, congenital heart disease, and heart transplant recipients with valve pathology.
17,24,33
In immunocompromised patients, with an absolute
neutrophil count of >1000/mL and fluctuance on examination had higher resolution rates
with incision and drainage but in patients with a lower absolute neutrophil count
(<500–1000/mL) and/or lack of fluctuance on examination may be successfully treated
with antibiotics alone in 30%–88%.
24,35
7.5.2 Treatment of ARF
Secondary fistulas related to IBD, cancer, irradiation, or iatrogenic injury should be treated
accordingly. The treatment of primary cryptogenic ARF is primarily surgery,
2
which is tailored to match the classification and the patient’s continence status. The key to a successful operation is excision or destruction of the infected anal gland in the intersphincteric
space
39
and obliteration of the internal opening
2,24
and any associated epithelialized
tracks with minimal sphincter division.
24
Watchful waiting in a patient with minimal symptoms or with a prohibitive operative
risk can be performed.
2
The risks associated with observation include recurrent ARA or
fistula and, rarely, malignancies arising in this long-standing tract.
2
Surgical options for
Chapter 7 • Anorectal Abscess and Fistula 89
ARF can be divided into two major types: a sphincter-preserving operation and a
nonsphincter-preserving operation. The selection of technique should be based on the
etiology, anatomy of the fistula, degree of symptoms, patient’s comorbidity, baseline anal
sphincter function, and the surgeon’s experience.
35
7.5.2.1 Nonsphincter-Preserving Operation
A. FISTULOTOMY
Simple ARF can be treated by fistulotomy with a high success rate ranging from 79% to
100%.
17,24,35
Increased risks of recurrence are associated with complex fistulas, failure
to identi fy the internal opening, and Crohn’s disease.
24,35
Postoperative alterations in
continence were reported to be between 0% and 73%,
24
which is dependent on patient
selection.
35
It is suitable for a low submucosal fistula or one that involves the anal sphinc-
ter complex <30%.
8
The risk factors for postoperative anal incontinence include preoperative incontinence, recurrent fistula, female gender, complex fistulas, and previous
fistula or anorectal surgery.
35
Contraindications for fistulotomy are anterior fistula (espe-
cially in females), fecal incontinence, IBD, and previous pelvic radiation.
8
Marsupialization of the wound edges was associated with less pain and fewer posto perative
complications.
35,40
B. FISTULECTOMY
Excision of the entire fistula tract also involves the removal of a part of the anal sphincter
resulting in a large sphincter defect. Fistulectomy was associated with prolonged healing
time and a higher risk of incontinence.
35,41
This procedure should not be undertaken for
simple anal fistula.
17
C. SETON
Seton is a foreign material (suture, rubber band, silastic vessel loop) placed through the
fistula tract that can be tightened sequentially at regular intervals until it eventually cuts
through the entire tissue thickness.
23
These sequential intervals allow the process of foreign body reaction to cause fibrotic healing of the recently cut area to re-ensure continuity
of the anorectal ring.
23,24
The healing rate of the cutting seton has been reported to be up
to 90%–94%.
35
A recurrence rate of 2%–8% has been reported.
8,23
This procedure involves
the division of the anal sphincter to some extent and there is no agreement as to its
safety.
17
A fecal incontinence rate of 12%–60% (2%–3% incontinence for solid stool) fol-
lowing this procedure was found.
8,23
Due to the high postoperative incontinence rate,
it should therefore be reserved for cases where no other alternatives are available
8
and
should be performed meticulously.
35
Drainage or loose seton can be used to control sepsis
8,24
in the emergency setting,
which is followed by a secondary procedure (endoanal advancement flap, fibrin glue, anal
plug) or, in Crohn’s disease, during the medical management.
8
This kind of seton is a thin,
90 ANORECTAL DISORDERS
nonabsorbable suture that is placed along the tract through the anus.8It provides drainage, prevents abscess recurrence, and is a marker for future fistula surgery.
1,8
Fig. 7.5
shows the classic procedures for the treatment of ARF and the amount of the anal
sphincter that is sacrificed during the operations.
7.5.2.2 Sphincter-Preserving Procedures
A. ADVANCEMENT FLAP
Treatment of complex FIA should not involve sphincter cutting in order to avoid postoperative fecal incontinence. The endorectal advancement flap is a technique that uses a
partial or full thickness anal mucosal-submucosa-muscle flap to cover the internal
opening.
8,24
The mean success rate of this technique is 70% (range 57%–90%)
17,24
with
a recurrence rate of about 13%–56%.
24,42,43
Full-thickness flaps have the lowest recurrence
rate (7.4%) compared to partial-thickness flaps (19%), and mucosal flaps (30%).
43
The risk
factors for failure include increased age, history of surgical abscess drainage, suprasphincteric fistula, horseshoe abscess, and high body mass index.
24,42
Mild or moderate
incontinence was reported in 7%–38% with decreased resting and squeeze anal pressure,
which may be due to the inclusion of the IAS into the flap.
24,43
Mucosal-, partial-, and
full-thickness flaps had incontinence rates of 9.3%, 10.2%, and 20.4%, respectively.
43
Low fistula Fistulotomy
Loose seton Cutting seton
FIG. 7.5 Low fistula and the classic procedures for treatment of anorectal fistula.
Chapter 7 • Anorectal Abscess and Fistula 91
The additional treatments for the fistula tract, i.e., core-out or curettage, have similar rates
of recurrence and incontinence.
42,43
The potential complications from the flaps are rectal
dissection and scarring of anorectal area.
8
The anodermal advancement flap is an alter-
native to the mucosal advancement flap.
25
It is performed by raising an anoderm and perianal skin flap, which includes the internal opening, and moving this up to suture it to the
proximal rectal mucosa.
25
Fig. 7.6 shows the procedure for the mucosal advancement flap
and the anodermal advancement flap.
B. FIBRIN GLUE INJECTION
This procedure is performed by simultaneously injecting thrombin and fibrinogen from a
two-chambered syringe into the fistula tract through the external opening.
17
The patient
should then be supine for several hours and avoid excessive movement during the first
operative month.
44
The obliteration of the tract is supposed to prevent the constant
re-introduction of luminal bacterial from entering
3
without the need for division of the
anal sphincter. The aim is to reduce the complications from surgical procedures. The host
cells will eventually lyse the fibrin plug and replace it with scar tissue.
44
A success rate of
25%–94% (10%–67% for complex fistula) and recurrence rate of up to 26%–59% have been
report.
17,23,3544
As it is relatively ineffective,35it should be used as second- or third-line
treatment.
23
The advantages of the use of fibrin glues are low morbidity, no risk of incontinence, simplicity, shorter hospital stays, less postoperative pain, repeatability, and it
does not preclude the possible use of other techniques.
17,23–25
High fistula Mucosal advancement flap
Anodermal advancement flap
FIG. 7.6 Mucosal advancement flap and anodermal advancement flap. The mucosal advancement flap (upper;
raised from rectal mucosa) and anodermal advancement flap (lower; raised from anoderm and perianal skin) are used
to cover the internal opening of the anorectal fistula.
92 ANORECTAL DISORDERS
C. ANAL FISTULA PLUG
An anal fistula plug (AFP) is a cone-shaped porcine acellular collagen matrix bioprosthesis
(Surgisis AFP, Cook Biotech Inc., United States) that is used to close the internal opening of
the fistula.
24,44
It is fixed to the submucosa and IAS44to avoid migration. Physical activity
should be limited in the early postoperative period.
44
The overall success rates range
between 24% and 92%
8
(70%–100% for low fistula and 80%–83% for complex fistula).
24
A failure rate of up to 87% has been reported.45Factors that may influence failure include
early dislodgement, multiple previous surgery, fistula between pelvic organs (anovaginal
fistula), Crohn’s disease, short fistula tract, HIV infection, and active smoking.
25,46
The
drawbacks of this technique are the high cost
44,46
and moderate risk of infection (21%
abscess formation).
44
Newer materials have been developed to improve the outcome,
including bioabsorbable synthetic fistula plug (GOREBIO-A, Gore medical, United States;
67% polyglycolide, 33% trimethylene carbonate), with success rates ranging from 16% to
73%.
17,47
Deterioration of continence was found in 6%.
47
Compared to the mucosal advancement flap, AFP had less postoperative pain, shorter
healing time and hospital stay without difference in healing rates, fewer complications,
and lower rates of recurrence.
48
Although in a recent randomized controlled study high
recurrence rates (66%) after AFP were found.
49
Autologous cartilage had also been used
as an AFP, but this technique has not been popularized.
50
Recently, a new material combining the silicone plug and cylindrical collagen matrices (Curaseal AF device) was used to
close the internal opening and form a scaffold for natural healing. A healing rate of 70%
without disturbance of continence has been shown.
51
D. LIGATION OF INTERSPHINCTERIC FISTULA TRACT
This technique of ligation and division of the fistula tract in the intersphincteric space was
reported in 2006 with a success rate of up to 94%.
52
The aim is to eliminate the source of
infection by obliterating the entrance from the anal canal
44
and removing the intersphinc-
teric nidus.
52
Successrates of 57%–94%(mean 74.6%) with a healing time of 4–8weeks, min-
imal morbidity, and no de novo incontinence were report.
24,44,53
The recurrence rate was
6%–18%. The postoperative complication rate was only 1.8%–5.5% (minor: persistent pain,
anal fissure, thrombosed hemorrhoid, wound infection, wound dehiscence, perianal hematoma, secondary bleeding).
24,54
The patient satisfaction rate was 72%–100%.53The risk factors for failure were obesity, smoking, multiple previous surgery, and the length of the fistula
tract >3 cm.
35,53
Preoperative seton drainage was not associated with increased success
rates.
55
The advantages of the ligation of intersphincteric fistula tract (LIFT) technique
are the preservation of the anal sphincters, minimal tissue injury, and short healing time.
54
The technique is easy-to-learn, inexpensive,
3,24,54
repeatable, and can be used in both sim-
ple and complex ARF,
35,56
includingthose associated with Crohn’s disease.57Modification of
the LIFT technique included omission of fistula tract division, excision of the lateral aspect
of the tract, and the combined use of a seton, fistula plug, or biological mesh interposition.
35
Up to now no additional benefit of combining procedures has been demonstrated.
55
Chapter 7 • Anorectal Abscess and Fistula 93
E. VIDEO-ASSISTED ABLATION OF THE FISTULA TRACT
This technique uses a 3.3 " 4.7 mm -diameter fiber-optic fistuloscope, which is insert ed
through the external opening to identify the internal opening, irrigate the tract with the
glycine-mannitol solution, and destroy the tract with a unipolar electrode.
8,17,54
Closure
of the internal opening can be performed using semicircular or linear staplers or a mucosal flap.
8,17,54
Synthetic cyanoacrylate glue can also be applied to reinforce the closure.
54
Secondary tracts or abscesses can be debrided and irrigated.17The healing rate was
between 58% and 87%, which may be the effect of the technique of closure of the internal
opening.
17,25
The mean complication rate was 4.8% (perianal sepsis, bleeding, pain, urinary retention) and the recurrence rates were 16%–18% at the median follow-up at
9months.
58
The main benefit of video-assisted ablation of the fistula tract (VAAFT) is
the precise identification of the fistula tract,
54
minimal risk of incontinence, short hospital
stays (1–4 days), and early return to work (1–11 days).
59
However, the cost for the special
instrument is high and the success rate has not been consistent.
25
F. ADIPOSE-DERIVED STEM CELLS
Mesenchymal stem cells (MSCs) derived from the adipose tissue of the patient have been
used to auto-injected into the anal fistula. These cells can be obtained from the subcutaneous fat by liposuction,
59
which provides 100 times more stem cells than bone marrow
aspiration.
54
After purification and expansion in the laboratory, the cells are prepared for
implantation.
59
An alternative method is to centrifuge the aspirated fat in a special auto-
mated system for 90–120min to get the fresh concentrated lipoaspirate.
60
The fistulous tract
should be thoroughly curetted prior to injecting the adipose-derived stem cells (ASC)
suspension, via a long, fine needle, into the tract walls.
59
The multipotent MSCs have the
potential to regenerate damaged tissue while inhibiting inflammation and fibrosis.
61
The
healing rate was reported to be between 35% and 90%.
26
For cryptogenic fistula, the available studies involved only a small number of patients and further information is awaited.
The main advantage of the ASC injection may be that continence is unaffected.
60
However,
the cost is high
26
and the preparation requires additional procedures (e.g., liposuction)
and instruments. In patients with Crohn’s disease, ASC was associated with a significant
improvement in healing without increased adverse events.
61,62
A combination of ASC
and fibrin glue or acellular dermal matrix (ADM) has been used to plug the internal
opening.
17,44,59
Addition of stem cells did not significantly improve the healing rate
compared with fibrin glue-injection alone.
17,44,54
Other novel materials that have been used for fistula treatment are platelet-rich
plasma, ADM, and acellular extracellular matrix (AEM), which showed high success rates
of 54%–100% in early follow-up.
17,63
G. OVER-THE-SCOPE-CLIP
These specialized 14 mm-nitinol clips with applicator have bee n used to close internal
openings from within the anal canal. Success rates of 70% – 90% have been report without
postoperative pain or discomfort.
44,64
The healing rate as a first-line treatment was 79%,
for recurrent fistula was 26%, and for fistula associated with IBD was 45%.
64
In long-term
94 ANORECTAL DISORDERS
follow-up a recurrence rate of 41% was found.65Time to recurrence was 7 months (range
3–11months).
65
However, the cost is high and the infected gland is left untreated.
44
H. LASER ABLATION
For recurrent fistula, a radial emitting laser probe (FiLaC) is inserted into the external
opening to destroy the fistula tract continuously during probe withdrawal. The aim is
to “burn” the tract in a controlled manner.66The laser wavelength used is 1470 nm and
the energy level is 100–120 J/cm.
66,67
The probe is withdrawn at a speed of 1 cm/6 s.
65
The internal opening is closed by endoanal advancement flap3or the internal opening
may be left open.
17
As a first-line treatment a success rate of 82% was reported in early
follow-up.
17,66
In a study that included both first-occurrence and recurrent fistulas, a
success rate of 71% was found on long-term follow-up.
67
The median healing time was
5weeks (range 3–8 weeks).
67
Postoperative complications included temporary pain or
anismus (18%), and moderate bleeding (6%).
67
A failure rate of 24% and recurrence rate
of 4% were reported.
67
The contraindication to laser treatment is the presence of an
abscess.
66,67
Although the procedure has had promising results, is easy-to-perform, and
is repeatable, the disposable laser probe and the equipment are expensive.
63
Newer modifications using photodynamic therapy that have improved the specificity of the burn area
by using an intralesional injection of 2% 5-aminolevu linic acid, have been reported wi th a
healing rate of 80%.
68
Further study is awaited. Fig. 7.7 demonstrates the novel sphincter
preservation techniques that are discussed in this chapter.
7.6 Treatment of ARA/ARF in Patients With Crohn’s Disease
Perianal involvement occurs in 40%–80% of patients with Crohn’s disease.
24
In 18% of
cases, the presentation is ARA or ARF.
68
Primary treatment is medical.
24,35
In an asymp-
tomatic Crohn’s fistula, no surgica l treatment is required.
24,35
In patients with symptomatic perianal disease, proctosigmoidoscopy is mandatory to check for the presence of
rectosigmoid involvement, which predicts a more aggressive course.
69
MRI or EAUS is
preferred to CT/fistulogram/EUA to define the inflammatory character of the lesion,
especially after failure of previous medical and/or surgical treatments.
69,70
When
symptomatic, antibiotics (metronidazole 750–1500mg/d and fluoroquinolones; ciprofloxacin 1 g/d) can improve symptoms in over 90% of patients.
23,35,69
The mainstay of
treatment is the use of tumor necrosis factor-alpha inhibitor (anti-TNFs, e.g., infliximab,
adalimumab).
23,69
For low-lying simple FIA, fistulotomy is safe and effective.
23,35,69
Heal-
ing rates were 56%–100% with a mild incontinence rate of 6%–12%.
23,35
However, the
extent of disease, presence of active proctitis, sphincter integ rity, previous anorectal
operations, gender, anterior fistula location, and stool consistency should be taken into
consideration.
10,35
In the presence of abscess or complex Crohn’s fistula, placement of
setons for drainage of sepsis and to prevent closure of the external opening has been
recommended.
10,23,35
It can be left in place throughout the course of anti-TNF therapy,
as too early removal may result in abscess recurrence.
10,35
Cutting seton should not be
Chapter 7 • Anorectal Abscess and Fistula 95
High fistula
LIFT Fistula plug Fibrin glue
injection
Mesenchymal stem cell
injection
VAAFT FiLaC
FIG. 7.7 Sphincter preservation techniques for treatment of anorectal fistula. LIFT, ligation of intersphincteric fistula tract; FiLaC, FiLaC-fistula-tract laser
closure; VAAFT, video-assisted ablation of fistula tract.
96 ANORECTAL DISORDERS
used as this was followed by incontinence in two-thirds of the patients.69Fibrin glue and
bioprosthesis plug demonstrated a success rate of fistula closure in only 25% and 31.5%,
respectively.
10
The mucosal advancement flap has shown a better success rate of 64%
(range 33%–93%), and an incontinence rate of 9.4% (range 0%–29%).
10,35
LIFT in Crohn’s
disease had shown a 67% healing rate without new onset of fecal incontinence,
10,35
but
this requires further study.
69
A promising treatment for perianal Crohn’s disease is MSC
injection. From the meta-analysis, MSC injection was associated with improved healing
at both early (OR ¼ 3.06 (95% CI 1.05–8.90), P ¼ 0.04) and long-term follow-up (OR ¼ 2.37
(95%CI 0.90–6.25), P ¼ 0.08).
62
There was no significant increase in adverse events.
62
Diverting stoma may be required to control severe perianal sepsis with insufficient
response to drainage, long-term seton placement, and medical management.
10,35
Diver-
sion rates range from 31% to 49%.
35
The initial response to diversion was up to 81% but
dropped later.
35
Proctectomy was required in 10%–20% of perianal Crohn’s disease
patients to control refractory symptoms.
10
This should be considered after a careful team
discussion consisting of patients, gastroenterologist, and surgeons.
35
The predictive factors are concomitant colonic disease, persistent perianal sepsis, prior temporary diversion, fecal incontinence, and anal canal stenosis.
35
A postproctectomy complication
rate of 25% was reported, which included poor wound healing and formation of perineal
sinus.
10
7.7 Conclusion
ARF and ARA are common problems. Cryptoglandular infection is the etiology in the major
group of patients. Preoperative imaging with MRI or EAUS provides the anatomical information for the disease and the anal sphincter. Various treatments have been proposed to
provide drainage, obturation of the internal opening, and obliteration of the tract. The
aim is to cure, reduce recurrence, and preserve anal-sphincter function. Classic operations
include fistulotomy and seton (loose or cutting). The sphincter-preserving procedures to
close the internal opening are endoanal advancement flap, anodermal advancement flap,
LIFT, fibrin glue, AFP, and over-the-scope-clip. The procedures to desiccate the tract are
VAAFT, FiLaC, and photodynamic therapy. The novel materials that are used to assist local
wound healing include ASC, platelet rich plasma, ADM, and AEM. Perianal Crohn’s disease
is a different entity for which the primary treatment is medication. A surgical procedure is
used to control sepsis, improve healing, and salvage the refractory cases.
References
1.
Abcarian H. Anorectal infection: abscess-fistula. Clin Colon Rectal Surg. 2011;24:14–21.
2. Rizzo JA, Naig AL, Johnson EK. Anorectal abscess and fistula-in-ano: evidence-based management.
Surg Clin N Am. 2010;90:45–68.
3. Pigot F. Treatment of anal fistula and abscess. J Visc Surg. 2015;152:S23–S29.
Chapter 7 • Anorectal Abscess and Fistula 97
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