FISTULA IN ANO – PERIANAL FISTULA

• MERCURY IMAGING INSTITUTE • SCO 172-173 SEC 9C

CHANDIGARH• MERCURY IMAGING CENTRE • SCO 16-17 SEC 20D

CHANDIGARH

18 YR MALE PATIENT WITH H/O TRAUMA OVER ANAL

VERGE REGION – PRESENTLY UNDER ASSESMENT FOR

PERIANAL FISTULA’S. PRESENT CASE –

GRADE ONE INTERSPHICTERIC FISTULOUS

TRACTS

BENEVOLENT DISPENSARY

TOST MARK’S HOSPITAL LONDON

Frederick Salmon

STARTED 'The Infirmary for the Relief of the Poor afflicted with Fistula and other Diseases of the Rectum'.PERFORMED 3500 OPERATIONS WITH NOT EVEN SINGLE FATALITY.

LEVATOR SLING

ISCHIO RECTAL FOSSA

ISCHIOANAL FOSSA

ANATOMY

IMPORTANT POINTS

EXTERNAL ANAL SPHINCTER • Voluntary control• Similar in signal to levator sling • 15% of the anal tone.• Straited muscle – continous with

the puborectalis / levator muscle

INTERNAL ANAL SPINCHTER• Involuntary Control• Smooth Muscle Responsible For

85 % Of The Anal Tone.• Continous With Circular Smooth

Muscle Of The Rectum.• Similar In Signal To Anal

Musculature• Relatively Hyperintense On Fat

Sat Sequences.

IMPORTANT POINTS ANAL CLOCK

• LITHOTOMY POSITION• DEFINE THE INTERNAL

OPENING 12”o clock – Anterior perineum

3“O CLOCK - Left Lateral aspect

6 ‘ o clock - Natal cleft

9 ‘ o clock – Rt side of the perineum

TRANSVERSE ANAL LINE • Define the cutaneous

opening (Predicts the internal opening)

CUTANEOUS OPENING

Rt side – Posterior to the anal canal

Lt side – Posterior to the anal canal

TRACT

Rt side – linear longitudinal tract with no secondary ramifications –present in the intersphincteric plane

Left side – linear longitudinal with no seconday ramifications- present in the intersphincteric plane

INTERNAL OPENING6”0clock – Rt side of the anal canal

3’0clock – left lateral aspect.

3D

BRIEF ABOUT PERIANAL FISTULA’S

ETIOLOGY• Crptoglandular hypothesis • Crohn disease • Tuberculosis • Trauma during childbirth,• Pelvic infection • Pelvic malignancy• Radiation therapy

PREOPERATIVE EVALUATION OF PERIANAL FISTULAS

• To define relation of the fistulous tract with sphincter complex ( intersphicteric , trans-sphincteric, suprasphicteric ).

• Define Secondary tracts/ Ramifications.

• Define horseshoe tracts.

St James's University Hospital ClassificationMR Imaging Grading of Perianal Fistulas

Grade 1: Simple Linear Intersphincteric Fistula.—

Grade 2: Intersphincteric Fistula with Abscess or Secondary Track.—

No secondary tract / ramifications

Secondary tract / ramifications present but

pathology is confined by the external sphincteric plane

St James's University Hospital ClassificationMR Imaging Grading of Perianal Fistulas

Grade 3: Trans-sphincteric Fistula.Grade 4: Trans-sphincteric Fistula with Abscess or Secondary Track within the Ischiorectal Fossa.

Transsphincteric extension with tract extending through the ischirectal / ischio anal

region.

Trans-spincteric fistula with absecss / secondary infection

in the ischiorectal fossa

St James's University Hospital ClassificationMR Imaging Grading of Perianal Fistulas

Grade 5: Supralevator and Translevator Disease.

Suprasphincteric ---- high extension through intersphincteric planeExtrasphincteric : Outside the sphincteric mechanism Translevator / supralevator.

CONTRST MR – EXTRA EDGE

DELINEATES THE TRACTS , INFECTIVE FOCI IN A BETTER WAY.