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References
1. Lockhard-Mummery JP. Diseases of the Rectum and Colon and Their Surgical Treatment. London: Bail-
liere; 1934.
2. Farouk R, Duthie GS, MacGregor AB, Bartolo DC. Sustained internal sphincter hypertonia in patients
with chronic anal fissure. Dis Colon Rectum. 1994;37(5):424–429.
8181401.
3.
Beaty JS, Shashidharan M. Anal fissure. Clin Colon Rectal Surg. 2016;29(1):30– 37.
4. Ploteau S, Labat JJ, Riant T, Levesque A, Robert R, Nizard J. New concepts on functional chronic pelvic
and perineal pain: pathophysiology and multidisciplinary management. Discov Med. 2015;19:185–192.
5. Mapel DW, Schum M, Von Worley A. The epidemiology and treatment of anal fissures in a population-
based cohort. BMC Gastroenterol. 2014;14:129.
6. Abramowitz L, Sobhani I, Benifla JL, et al. Anal fissure and thrombosed external hemorrhoids before
and after delivery. Dis Colon Rectum. 2002;45(5):650–655.
7. Klosterhalfen B, Vogel P, Rixen H, Mittermayer C. Topography of the inferior rectal artery: a possible
cause of chronic, primary anal fissure. Dis Colon Rectum. 1989;32(1):43–52.
8. Schouten WR, Briel JW, Auwerda JJ. Relationship between anal pressure and anodermal blood flow.
The vascular pathogenesis of anal fissures. Dis Colon Rectum. 1994;37(7):664–669.
9. van Meegdenburg MM, Trzpis M, Heineman E, Broens PM. Increased anal basal pressure in chronic
anal fissures may be caused by overreaction of the anal-external sphincter continence reflex. Med
Hypotheses. 2016;94:25–29.
10. Schouten WR, Blankensteijn JD. Ultra slow wave pressure variations in the anal canal before and after
lateral internal sphincterotomy. Int J Colorectal Dis. 1992;7(3):115–118.
11. Felt-Bersma RJ, Gort G, Meuwissen SG. Normal values in anal manometry and rectal sensation: a
problem of range. Hepatogastroenterology. 1991;38(5):444–449.
12. Deen-Molenaar CH, Jordanov T, Felt-Bersma RJ. Intersphincteric infection due to an anal fissure. Int
J Colorectal Dis. 2016;31(3):727–728.
13. Eisenhammer S. The surgical correction of chronic internal anal (sphincteric) contracture. S Afr Med J.
1951;25(28):486–489.
14. Khubchandani IT, Reed JF. Sequelae of internal sphincterotomy for chronic fissure in ano. Br J Surg.
1989;76(5):431–434.
15. Garcia-Aguilar J, Belmonte C, Wong WD, Lowry AC, Madoff RD. Open vs. closed sphincterotomy for
chronic anal fissure: long-term results. Dis Colon Rectum. 1996;39(4):440–443.
16. Garg
P, Garg M, Menon GR. Long-term continence disturbance after lateral internal sphincterotomy
for chronic anal fissure: a systematic review and meta-analysis. Colorectal Dis. 2013;15(3):e104–e117.
17. Stewart Sr DB, Gaertner W, Glasgow S, Migaly J, Feingold D, Steele SR. Clinical practice guideline for
the management of anal fissures. Dis Colon Rectum. 2017;60(1):7–14.
18. https://richtlijnendatabase.nl/richtlijn/proctologie/fissura_ani.html.
19.
Nelson RL, Manuel D, Gumienny C, et al. A systematic review and meta-analysis of the treatment of
anal fissure. Tech Coloproctol. 2017;21(8):605–625.
20. Ebinger SM, Hardt J, Warschkow R, et al. Operative and medical treatment of chronic anal fissures-a
review and network meta-analysis of randomized controlled trials. J Gastroenterol. 2017;52(6):663–676.
21. Farkas N, Solanki K, Frampton AE, Black J, Gupta A, West NJ. Are we following an algorithm for man-
aging chronic anal fissure? A completed audit cycle. Ann Med Surg (Lond). 2015;5:38–44.
22. Jensen SL. Maintenance therapy with unprocessed bran in the prevention of acute anal fissure recur-
rence. J R Soc Med. 1987;80(5):296–298.
78 ANORECTAL DISORDERS
23. Jensen SL. Treatment of first episodes of acute anal fissure: prospective randomised study of ligno-
caine ointment versus hydrocortisone ointment or warm sitz baths plus bran. Br Med J (Clin Res
Ed). 1986;292(6529):1167–1169.
24. Dodi G, Bogoni F, Infantino A, Pianon P, Mortellaro LM, Lise M. Hot or cold in anal pain? A study of the
changes in internal anal sphincter pressure profiles. Dis Colon Rectum. 1986;29(4):248–251.
25. Shahid S, Ramzan Z, Maurer AH, Parkman HP, Fisher RS. Chronic idiopathic constipation: more than a
simple colonic transit disorder. J Clin Gastroenterol. 2012;46(2):150–154.
26. Lee HJ, Boo SJ, Jung KW, et al. Long-term efficacy of biofeedback therapy in patients with dyssynergic
defecation: results of a median 44 months follow-up. Neurogastroenterol Motil. 2015;27(6):787–795.
27. Nelson RL, Thomas K, Morgan J, Jones A. Non-surgical therapy for anal fissure. Cochrane Database Syst
Rev. 2012;2:CD003431.
28. Sajid MS, Whitehouse PA, Sains P, Baig MK. Systematic review of the use of topical diltiazem compared
with glyceryltrinitrate for the nonoperative management of chronic anal fissure. Colorectal Dis.
2013;15(1):19–26.
29. Jost WH, Schimrigk K. Use of botulinum toxin in anal fissure. Dis Colon Rectum. 1993;36(10):974.
30. Bobkiewicz A, Francuzik W, Krokowicz L, et al. Botulinum toxin injection for treatment of chronic anal
fissure: is there any dose-dependent efficiency? A meta-analysis. World J Surg. 2016;40(12):3064–3072.
31. Sahebally SM, Meshkat B, Walsh SR, Beddy D. Botulinum toxin injection vs topical nitrates for chronic
anal fissure: an updated systematic review and meta-analysis of randomized controlled trials. Colo-
rectal Dis. 2018;20(1):6–15.
32. Brisinda D, Maria G, Fenici R, Civello IM, Brisinda G. Safety of botulinum neurotoxin treatment in
patients with chronic anal fissure. Dis Colon Rectum. 2003;46(3):419–420.
33. Murad-Regadas SM, Fernandes GO, Regadas FS, et al. How much of the internal sphincter may be
divided during lateral sphincterotomy for chronic anal fissure in women? Morphologic and functional
evaluation after sphincterotomy. Dis Colon Rectum. 2013;56(5):645–651.
34. Sahebally SM, Walsh SR, Mahmood W, Aherne TM, Joyce MR. Anal advancement flap versus lateral
internal sphincterotomy for chronic anal fissure—a systematic review and meta-analysis. Int
J Surg. 2018;49:16–21.
35. Andjelkov K, Sforza M, Barisic G, Soldatovic I, Hiranyakas A, Krivokapic Z. A novel method for treat-
ment of chronic anal fissure: adipose-derived regenerative cells—a pilot study. Colorectal Dis. 2017;19
(6):570–575.
36. Lolli P, Malleo G, Rigotti G. Treatment of chronic anal fissures and associated stenosis by autologous
adipose tissue transplant: a pilot study. Dis Colon Rectum. 2010;53(4):460–466.
37. Yakovlev A, Karasev SA. Successful treatment of chronic anal fissure utilizing sacral nerve stimulation.
WMJ.
2010;109(5):279–282.
38. Vollebregt PF, van Bodegraven AA, Markus-de Kwaadsteniet TML, van der Horst D, Felt-Bersma RJF.
Impacts of perianal disease and faecal incontinence on quality of life and employment in 1092
patients with inflammatory bowel disease. Aliment Pharmacol Ther. 2018;
https://doi.org/10.1111/
apt.14599
[Epub ahead of print].
39.
Malaty HM, Sansgiry S, Artinyan A, Hou JK. Time trends, clinical characteristics, and risk factors of
chronic anal fissure among a national cohort of patients with inflammatory bowel disease. Dig Dis
Sci. 2016;61(3):861–864.
40. D’Ugo S, Franceschilli L, Cadeddu F, et al. Medical and surgical treatment of haemorrhoids and anal
fissure in Crohn’s disease: a critical appraisal. BMC Gastroenterol. 2013;13:47.
41. Cracco N, Zinicola R. Sphincterotomy for anal fissure in Crohn’s disease: is it dangerous? Int
J Colorectal Dis. 2016;31(3):761.
Chapter 6 • Anal Fissure 79
42. Wallenhorst T, Brochard C, Le Balch E, et al. Anal ulcerations in Crohn’s disease: natural history in the
era of biological therapy. Dig Liver Dis. 2017;49(11):1191–1195.
43. Bemelman WA, Warusavitarne J, Sampietro GM, et al. ECCO-ESCP consensus on surgery for Crohn’s
disease. J Crohns Colitis. 2018;12(1):1–16.
44. Bissessor M, Fairley CK, Read T, Denham I, Bradshaw C, Chen M. The etiology of infectious proctitis in
men who have sex with men differs according to HIV status. Sex Transm Dis. 2013;40(10):768–770.
45. Viamonte M, Dailey TH, Gottesman L. Ulcerative disease of the anorectum in the HIV+ patient. Dis
Colon Rectum. 1993;36(9):801–805. Erratum in: Dis Colon Rectum 1993 Nov;36(11):990.
46. Gopal P, Shah RB. Primary anal canal syphilis in men: the clinicopathologic spectrum of an easily over-
looked diagnosis. Arch Pathol Lab Med. 2015;139(9):1156–1160.
80 ANORECTAL DISORDERS
7
Anorectal Abscess and Fistula
Kasaya Tantiphlachiva
DEP A R T MEN T O F S U R G E RY, C H UL A L O N GKOR N UN I VE R S I T Y, B A N GK O K , THAI L A N D
7.1 Introduction
Anorectal abscess (ARA) and fistula (ARF) are the acute and chronic form of anorectal
infection, respectively.
1
It is one of the most common anorectal problems.1The major
cause of the abscess is infection of the anal gland, which has become obstructed with
debris known as the cryptoglandular theory.
2
Generally, there are 4–12 anal glands situ-
ated around the anal circumference, predominantly in the posterior.
3–5
In most people
these glands are situated in the areolar tissue of the intersphincteric plane, which is rich
in lymphatics
3
and they drain into the anal crypts at the level of the dentate line.3The presence of the lymphoid tissue around the glands may account for the other causes of anorectal inflammation, including tuberculosis and Crohn’s diseases.
6
The suppuration
spreads into adjacent spaces
1
via the path of the least resistance.2It may spread downwards to the anal margin, upwards along the rectal wall, or outwards through the external
sphincter into the ischiorectal space.
6
The overall incidence rate of ARA was 20.2 per
100,000. The rate of subsequent fistula formation was 15.5% in idiopathic cases and
41.6% in patients with inflammatory bowel disease (IBD).
1,2,7
The median age at the time
of first presentation is 40 (range 29–52) years.
7
The overall incidence of ARF (or fistula-inano) in the general population is 8.6 per 100,000 per year (12.2 per 100,000 males and 5.5
per 100,000 female).
1,3,8
The common age of presentation was between 20 and 60 years
(mean 40).
1
The median time to presentation of fistula following an abscess drainage
was 7.0 m onths (range 6.9–7.1 months).
7
Predictors of fistula formation were IBD, female
gender, age at time of the first abscess (41–60 years), and intersphincteric/ischiorectal
abscess location (compared to perianal location).
7
The lifestyle risk factors that increased
the risk of developing fistula are a body mass index of >25.0 kg/m
2
, high daily salt intake,
history of diabetes, hyperlipidemia, dermatosis (urticaria, eczema, or contact dermatitis)
within the last 6 months, anorectal surgery, smoking and alcohol intake, sedentary lifestyle, excessive intake of spicy/greasy food, little exercise, and prolonged toilet time.
9
Besides the anal gland infection, other causes of ARA/ARF include IBD, fungal infec-
tion, mycobacterial infection, neoplasm, and trauma.
2
Up to 30% of individuals with
Crohn’s disease will develop perianal lesions
8,10
and 18% present as ARF or ARAs.
10
Ingested foreign bodies such as chicken or fish bones, pin perforation,
11,12
penetrating
trauma of anorectum, low rectal cancer, and anal-gland cancer are other possible causes
of ARF.
1
Anorectal Disorders. https://doi.org/10.1016/B978-0-12-815346-8.00007-2
© 2019 Elsevier Inc. All rights reserved.
81
7.2 Classification
ARAs are classified by the location in the perirectal space of the purulent collection: perianal abscess (located superficially around the anal verge), intersphincteric abscess
(located in the intersphincteric space), ischiorectal abscess (located in the ischiorectal
space), and supralevator abscess (located in the supralevator level).
2
Most of a supralevator abscess is an extension of an intersphincteric abscess, which extends upwards along
the intersphincteric plane.
1,2
On a rare occasion a supralevator abscess may result from
pelvic sepsis due to an appendicitis, diverticulitis, or gynecological infection.
1
Fig. 7.1
demonstrates the types of ARA. Perianal, ischiorectal, intersphincteric, and supralevator
abscesses are present in 43%, 23%, 21%, and 7% of the ARA patients, respectively.
2,13
Hanley et al. described a type of abscess that originated from the anal gland, which connected
to a crypt near the posterior midline and was located in the deep postanal space.
14
This
type of abscess has potential to spread to the ischiorectal space, unilaterally or bilaterally,
as a so-called semihorseshoe or horseshoe abscess.
ARFs are classified by their passage to the anal sphincter complex. The most widely
used is the Parks classification
1,6,8
which consists of four types:
1. Intersphincteric fistula—tracking from anal cr ypt through internal anal sphincter (IAS)
and then between internal and external anal sphincter (EAS) down to perianal skin
at anal verge.
1,6,8
It is the most common type of ARF and is usually preceded by a
perianal abscess.
8
It can extend up high in the intersphincteric plane and presents as
supralevator abscess.
1,2,8
2. Transphincteric fistula—tracking through IAS and EAS into the ischiorectal fossa,
then down to the skin below.
1,6,8
It can be divided into high and low type.
2
Rectum
Levator ani
Puborectalis
Superficial EAS
Subcutaneous EAS
Intersphincteric abscess
Perianal abscess
Ischioanal abscess
Supralevator abscess
IAS
FIG. 7.1 Types of anorectal abscess.
82 ANORECTAL DISORDERS
3. Suprasphincteric fistula—originating from intersphincteric plane, extending up to
the supralevator area and tracking over puborectalis muscle into the ischiorectal
fossa and then to skin below.
6,8
4. Extrasphincteric fistula—typically arise from the pelvis or rectum above the dentate
line, cross the proximal to the sphincter complex, tracking through the levator ani into
ischioanal fossa down to the perianal skin, without involvement of IAS or EAS.
2,6,8
There is an additional subtype of ARF which courses in the submucosa without traversing
either IAS or EAS called subcutaneous fistula
15
or intersphincteric fistula.8This type is
often associated with anal fissures.
8
Parks et al. estimated the frequencies of intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric fistula as being 70%, 23%,
2%, and 3%, respectively.
6,15
A later report showed the percentage of subcutaneous, inter-
sphincteric, transsphincteric, suprasphincteric, and extrasphincteric as 16.4%, 55.9%,
21.3%, 3.4%, and 3%, respectively.
16
ARF can also be classified as low and high types.
Low-type fistulas pass through the lower third of the IAS and EAS muscles and high-type
fistulas pass higher than lower third of the anal sphincters.
8
The objective of these clas-
sifications is to predict the risk of incontinence after surgery.
8
However, there are other
risk factors that should be considered. For this purpose, ARF is divided into simple and
complex types.
8,17
Simple fistulas include intersphincteric fistula and low transsphincteric
fistula that involves less than 30% of the sphincter complex.
17
Complex fistulas include
high transsphincteric, suprasphincteric, extrasphincteric, recurrent and horseshoe fistulas, fistula with multiple tracts, anterior tract in female, presence of IBD or malignancy,
previous pelvic irradiation, presence of incontinence or chronic diarrhea, and involvement of other organs (e.g., vagina, base of scrotum, and urinary bladder).
8,17
Fig. 7.2
Demonstrates types of anorectal fistula.
The pathogenic organisms found in ARA and ARF are polymicrobial aerobic and anaer-
obic bacteria.
13,18
The common isolated organisms are Escherichia coli (22%–25%),
Enterococcus (16%–22%), and Bacteroides fragilis (20%–26%).
13,18
The rarer organisms that
can be found are Mycobacterium tuberculosis, Actinomycosis, Chlamydia trachomatis
(lymphogranuloma venereum), and fungus.
13,18
The presence of these gut-associated
organisms is indicative of the presence of ARF.
19
7.3 Clinical Presentation
Patients with acute ARA present with perianal pain and are febrile with a hot, erythematous, fluctuant, tender, indurated swelling adjacent to the anus.
1,3,20
Spontaneous drain-
age may occur.
20
If untreated or inadequately treated, infection may involve the perineal
soft tissue and fascia (Fournier’s gangrene), which can be fatal.
2,20,21
This condition is
likely to occur in patients with comorbid risk factors including diabetes, body mass index
>30 kg/m
2
, hypertension, end-stage renal disease, liver failure, smoking, alcohol abuse,
advanced age, and immunosuppressed states.
21,22
Patients with ARF may complain of
drainage, bleeding or pain, and fever.
23
Chapter 7 • Anorectal Abscess and Fistula 83
Diagnosis of ARA and ARF is usually based on history and physical ex amination.
17,24
A disease-specific history, emphasizing symptoms, risk factors, previous anal surgery,
obstetric injury, gastrointestinal symptoms, and baseline fecal continence should be
taken.
8,24,25
Useful information can be obtained during a digital rectal examination.25During inspection the practitioner should look for a bulging area, the location of an external
opening, purulent discharge, the presence of secondary cellulitis, any scaring from previous surgery, and evidence of fecal incontinence.
8,25
An external opening that is closed to
the anal canal likely belongs to a superficial or intersphincteric fistula and an external
opening that lies at 2–3cm from the anus likely belongs to a transsphincteric, suprasphincteric, or extrasphincteric fistula.
25
By palpation an internal opening and tract may
be identified.
8
Bidigital examination, with the index finger inside and the thumb outside
the anal canal, may help identify the fistulous tract as a cord-like lesion under the skin.
23
Anal sphincter bulk, tone, and defect should be assessed.8Any point of tenderness should
be noted. In an acute abscess, rectal examination and anoscopy should be gently performed and kept to a minimum as they could aggravate pain.
26
A supralevator abscess
may present as dull pain in the lesser pelvis or back, fever, and othe r nonspecific symptoms.
26
An intersphincteric abscess may not have significant external findings24but severe
pain may preclude digital rectal examination and examination under anesthesia (EUA)
may be more appropriate.
2
Differential diagnosis of ARAs includes hidradenitis suppurativa, a skin furuncle, infections such as herpes simplex, HIV, tuberculosis, syphilis,
and actinomycosis.
17,24
The obtained clinical information may alert the physician to
the possible etiology.
8,24
Features suggestive of Crohn’s disease or atypical causes, includ-
ing large skin tags or multiple fistulas, require a more detailed workup.
24
Rectum
Levator ani
Puborectalis
Superficial EAS
Subcutaneous EAS
IAS
Subcutaneous fistula
Intersphincteric fistula
Low transphincteric fistula
High transphincteric fistula
Suprasphincteric fistula
Extrasphincteric fistula
FIG. 7.2 Types of anorectal fistula.
84 ANORECTAL DISORDERS
7.4 Preoperative Imaging
For the preparation of an appropriate management plan, it is important to identify the
location of the internal opening and to map the fistula course.
8
This can be done by various methods. The classic Goodsall’s rule may be used to determine the location of an
internal opening.
8,17
According to the rule, an imaginary transverse line across the anus
is drawn. If the external opening is located anterior to this line, the tract will run directly
toward the anal canal. If the external opening is located posterior to this line, the tract will
curve posteriorly toward an internal opening in the midline.
8,23,25
The predictive accuracy
of Goodsall’s rule is 90% for posterior fistula, but only 49% for ant erior fistulas.
8,13,23,25
High predictive accuracy was seen in superficial fistulas (97%) and intersphincteric fistula
(84%), but decreased significantly for transsphincteric fistulas (69%).
27
The reliability also
decreases in the case of recurrent fistulas,
17,24
long fistula tracts, fistulas with an external
opening located >3 cm from the anal verge, and fistulas associated with Crohn’s disease,
tuberculosis, or malignancy.
8,24
Conventional fistulography, performed by injecting a water-soluble dye through the
external opening and taking an X-ray,
8
is not recommended for the diagnosis of ARF
because of low accuracy (16%) and poorly tolerance of the patient.
17,24
The technique does
not provide information about the relationship between the tract and the anal sphincter
complex.
8
Also, it cannot be used for a fistula that has an external opening that has been
closed or plugged.
8
Because of the lack of sensitivity and visualization of the tract, patients
had to undergo an EUA to determine the type of anorectal fistula.
2
Tract injecting technique using hydrogen peroxide or methylene blue helps the surgeon
in the identification of an internal opening
2,24
with a success rate of 80%–90%.24The sub-
sequent procedure is then dictated by the location and the path of the tract.
2
However, in
complex cases additional investigations may help to improve preoperative planning, i.e.,
detect occult abscess and secondary tracts, or to assess the integrity and function of the
anal sphincter muscles.
17
Endoanal ultrasound (EAUS) is a cost-effective technique that may be the first-line
method for imaging complex fistulas.
17,23
The reported accuracy in detecting abscesses
or fistulas was between 80% and 89%.
17,24
The accuracy of EAUSis significantly better than
physical examination in detecting the primary tract (88.8% vs 85.0%, P ¼ 0.023), horseshoe
extension (85.7% vs 57.7%, P < 0.0001), and the location of the internal opening (85.5% vs
69.1%, P < 0.0001).
28
Three-dimensional (3D) technique improved the accuracy for identification of the primary tract up to 94% and for the localization of the internal opening to
91%.
23
Hydrogen peroxide (H2O2) enhancement, performed by injection through the
external opening, further improve the diagnostic accuracy and identification of the
internal opening up to 94%.
17,29,30
When compared to EUA, peroxide-enhanced EAUS
showed good to very goo d agreement with EUA in the classification of primary fistula tract
(κ ¼ 0.93), identification of internal opening (κ ¼ 0.97), and detection of secondary fistula
extensions (κ ¼ 0.71).
29
Overall sensitivity and specificity of 3D-EAUS in the diagnosis of
perianal sepsis was 98.3% and 91.3%, respectively.
29
Peroxide-enhanced EAUS findings
are comparable to magnetic resonance imaging (MRI) with close to 90% concordance.
24
Chapter 7 • Anorectal Abscess and Fistula 85
EAUS is useful for planning the appropriate operation.29The high diagnostic accuracy
leads to successful operations in 98% of patients.
31
With adjunctive volume render mode,
the interpreter can better classify the type of fistula.
32
The limitation of EAUS is that it can-
not be performed in patients with anal stricture
23
and it requires an experienced operator
for diagnostic reliability.
17,33
In the emergency setting, it may be difficult to localize the
fistulous tract and the patient may not tolerate the anal probe.
33
In such a situation EAUS
under anesthesia can be performed. The suboptimal visualization of the lev ator plate may
lead to limitation in the assessment of the secondary tract in the far field.
17
Fig. 7.3 is an
example of an EAUS examination of an anterior transsphincteric fistula using multiplanar
views and volume render mode (
Fig. 7.3D–F). The abscess and tract are heterogeneous
hypoechoic lesions in the perianal space and through the anal sphincter complex.
Fig. 7.4 demonstrates the use of EAUS with volume render mode and H
2O2
enhancement
in detecting a high transsphincteric fistula that has intersphincteric extension up to the
supralevator level.
Computed tomography (CT) scan may be useful in acute complex anorectal sepsis. In
an emergency patient s usually present with perineal pain, fever, and leukocytosis, and
FIG. 7.3 Endoanal ultrasonography (EAUS) views of an anterior transsphincteric fistula. (A–C) Normal EAUS
views. (D–F) Volume render mode views. (A, D) The level of lower anal canal. (B, E) The level of mid anal canal.
(C, F) Sagittal plane.
86 ANORECTAL DISORDERS
perineal examination without anesthesia may not be possible.
24,33
A CT scan is readily
available and effective.
17,33
In nonemergency, CT fistulography provides a clear view of
the fistulous tract and its relationship to the pelvic structure
34
and has an advantage over
MRI in allowing the visualization of an air-containing abscess.
34
It is valuable to
FIG. 7.4 Endoanal ultrasound (EAUS) view of a right transsphincteric fistula with supralevator intersphincteric
extension. (A, C, E, and G) Peroxide-enhanced normal EAUS views. (B, D, F, and H) Peroxide-enhanced volume render
mode views. The bright white area is the fistula tract traced from the level of lower anal canal (A, B), mid anal canal
(C, E), upper anal canal (E, F), and supralevator level (G, H). (I, J) Coronal views in different planes to show the
high transsphincteric tract (yellow arrow) extending up in the right ischiorectal fossa and the intersphincteric
extension of the abscess up to supralevator level (white arrow).
Chapter 7 • Anorectal Abscess and Fistula 87
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