This document discusses anorectal abscesses and fistula in ano. It begins by defining anorectal abscesses as infections of soft tissues around the anal canal that form abscess cavities, often coinciding with fistula in ano. The peak incidence is in the third and fourth decades of life, affecting males more often. Causes include infection of anal glands, injury, Crohn's disease, and tuberculosis. Pathophysiology involves infection of anal glands leading to abscess formation in intersphincteric spaces. Abscesses are classified based on their location such as perianal, ischiorectal, or pelvirectal. Treatment involves incision and drainage. Fistula in ano results from

1. Dr. Dinesh. M.G
Professor of Surgery
J.J.M.M.C.
Davangere

2. Introduction
 Anorectal abscess represents infection of the soft tissues
surrounding the anal canal and rectum with formation of
discrete abscess cavity
 Many anorectal abscesses coincide with fistula in ano

3. Incidence
 Peak incidence in 3rd and 4th decades
 Males are more affected with male to female ratio of 2:1

4. Aetiology
 Infection of anal gland in relation to crypts( 90%)
 Injury to anorectum( e.g. fishbone)
 Blood borne infection
 Extension of cutaneous boil
 Fissure in ano
 Crohn’s disease
 Tuberculosis
 Rectal malignancy
Patients with diabetes and AIDS are more prone for
anorectal abscesses

5. Pathophysiology
 Infection of anal glands( about 4-10 near dentate line) in
anal crypts leads to suppuration and abscess typically
forms in the intersphincteric space and can spread along
various spaces
 Common causative organisms
 E.coli
 Bacteroids
 B. Proteus
 Streptococcus
 Staphylococcus aureus
 Fistula is more likely if pus culture reveals bowel
organisms rather than skin organisms

6. Classification
 Perianal
 Submucosal
 Ischiorectal
 Pelvirectal(supralevator)
 Fissure abscess

7. Perianal abscess(60%)
 Occurs due to suppuration of anal gland or suppuration of
thrombosed external pile
 Lies in the region of subcutaneous portion of external
sphincter
 Presents with pain in perianal region
 Fever
 Tender soft swelling is felt at the anal verge
Treatment
 Incision and drainage by cruciate incision or deroofing
 Antibiotics, analgesics and Sitz bath

8. Ischiorectal abscess(30%)
 Ischiorectal fossa contain poorly vascularised fat
 Right and left communicate with each other posteriorly, so
infection spreading can produce horse-shoe abscess
 Occurs when intersphincteric abscess extends laterally
through the external sphincter
 Rarely infection can be lymphatic or bloodborne
 Presents as tender indurated brawny swelling over
ischiorectal fossa with high fever
 Treated by incision and drainage by cruciate incision

9. Ischiorectal abscess

10. Cruciate incision & deroofing

11. Submucous abscess(5%)
 Occurs above dentate line
 Presents with aching pain in anorectum
 Tender soft smooth swelling in anorectum on digital rectal
examination without an external swelling
 Treated by antibiotics & drainage using sinus forceps

12. Pelvirectal abscess
 Situated between upper surface of levator ani and pelvic
peritoneum
 It is like a pelvic abscess secondary to appendicitis,
salpingitis, diverticulitis and Crohn’s disease
 Treated by transrectal/transvaginal drainage or by usg
guided percutaneous drainage after investigations for the
cause
Fissure abscess
 Subcutaneous abscess in the vicinity of anal fissure
 Treated by incision and drainage

13. Fistula in ano
 It is a track lined by granulation tissue which connects
perianal skin superficially to anal canal or rectum
 It usually results from an ano-rectal abscess which burst
spontaneously or was opened inadequately
 Anal fistula can have multiple accessory tracts as well as
external openings
 Anal fistulae can also be associated with
 HIV
 Tuberculosis
 Crohn’s disease
 Rectal malignancy
 Radiation exposure

14. Classification of anal fistulae
Standard classification
1. Subcutaneous
2. Submucous
3. Low anal
4. High anal
5. Pelvirectal

15. Classification of anal fistulae
Park’s classification
1. Intersphincteric
2. Transphincteric
3. Supralevator /Suprasphincteric
4. Extrasphincteric

16. Other classifications
Low fistula High fistula
Internal opening below anorectal
ring
Internal opening at or above
anorectal ring
Simple fistula Complex fistula
Do not have secondary tracts Have multiple secondary tracts

17. Low-level fistulae
Clinical features
 Seropurulent discharge with one or more opening on one
side of midline with induration of tract
 Horese shoe fistulae involving both ischiorectal fossae
present with openings on both sides
 Anorectal examination may reveal nodular internal
opening

18. Goodsall’s rule
 Anterior external opening
is of direct type
 Posterior external opening has
curved track with an internal
opening in the midline
posteriorly

19. Investigations
 Complete haemogram and HIV
 Chest x-ray for pulmonary TB
 Fistulogram- not popular nowadays
 Transrectal ultrasound : useful to identify internal opening
 MRI fistulogram
Endorectal ultrasound MRI of anal fistulae

20. Differential diagnosis
 Urethral fistula in males
 Chronic infection of Bartholin’s gland in females
 Pilonidal sinus
 Hidradenitis suppurativa
 Carcinoma
 Crohn’s,Tuberculosis and Ulcerative colitis

21. Treatment
 Fistulotomy
 Fistulectomy
 Seton
Newer methods of treatment
 Anal fistula plug repair
 Injection of glue into the fistulous tract
 Mucosal flap procedure
 LIFT( Ligation of intersphincteric fistula track)
 VAAFT procedure( Video assisted anal fistula track
ligation)

22. Treatment
 Fistulotomy is laying open of track after probing the
fistulous track

23. Treatment
 Fistulectomy is complete excision of fistulous tract after
probing

24. Treatment
 Seton is a non absorbable suture (e.g. silk) or tape that is
passed across the fistula and tied

25. Treatment
 Anal fistula plug repair
 Glue injection

26. Treatment
 Video assisted anal fistula track ligation

27. High-level fistula
 Internal opening is above anorectal ring
 Common causes are
 Crohn’s disease
 Ulcerative colitis
 Trauma
 Carcinoma
 Foreign body
 Investigations
 Colonoscopy/barium enema, chest x-ray & biopsy

28. Treatment of high-level fistulae
 Staged procedure
 Initial colostomy
 Definitive procedure with sphincter repair
 Colostomy closure
 Seton
 Loose setons
 Cutting setons

29. Thank you