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Thursday, January 14, 2010

Fistula In Ano:

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“A fistula-in-ano is a hollow tract lined with granulation tissue connecting a primary opening inside the anal canal to a secondary opening in the perianal skin”.



HISTORY:
References to fistula-in-ano date to antiquity.
Hippocrates made reference to surgical therapy for fistulous disease.
The English surgeon John Arderne (1307-1390) wrote Treatises of Fistula in Ano; Hemorrhoids,
Clysters in 1376, which described fistulotomy and seton use.
Historical references indicate that Louis XIV was treated for an anal fistula in the 18th century.

In the late 19th and early 20th centuries, prominent physician/surgeons, such as Goodsall and Miles, Milligan and Morgan, Thompson, and Lockhart-Mummery, made substantial contributions to the treatment of anal fistula.

These physicians offered theories on pathogenesis and classification systems for fistula-in-ano.

Since this early progress, little has changed in the understanding of the disease process.
Over the last 30 years, many authors have presented new techniques and case series in an effort to minimize recurrence rates and incontinence complications.
Despite 2500 years of experience, fistula-in-ano remains a perplexing surgical disease.

FREQUENCY:
The prevalence rate is 8.6 cases per 100,000 population.
The prevalence in men is 12.3 cases per 100,000 population.
In women, it is 5.6 cases per 100,000 population.
The male-to-female ratio is 1.8:1.
The mean age of patients is 38.3 years.

CAUSES:
Fistula-in-ano is nearly always caused by a previous anorectal abscess.
Anal canal glands situated at the dentate line afford a path for infecting organisms to reach the intramuscular spaces.

DEVELOPE SECONDARY TO:
Trauma,
Crohn disease,
Anal fissures,
Carcinoma,
Radiation therapy,
Actinomycoses,
Tuberculosis, and
Chlamydial infections.

PATHOPHYSIOLOGY:
The cryptoglandular hypothesis states that an infection begins in the anal gland and progresses into the muscular wall of the anal sphincters to cause an anorectal abscess.

REASONS FOR FISTULA FORMATION:
Following surgical or spontaneous drainage in the perianal skin, occasionally a granulation tissue–lined tract is left behind, causing recurrent symptoms.

Multiple series have shown that the formation of a fistula tract following anorectal abscess occurs in 7-40% of cases.

CLINICAL HISTORY:
Patients often provide a reliable history of
Previous pain,
Swelling,
Spontaneous or planned surgical drainage of an anorectal abscess.

SIGNS AND SYMPTOMS:
Perianal discharge
Pain
Swelling
Bleeding
Diarrhea
Skin excoriation
External opening

PAST MEDICAL HISTORY:
Important points in the history that may suggest a complex fistula include the following:
Inflammatory bowel disease
Diverticulitis
Previous radiation therapy for prostate or rectal cancer
Tuberculosis
Steroid therapy
HIV infection

PHYSICAL EXAMINATION:
Physical examination findings remain the mainstay of diagnosis.
The examiner should observe the entire perineum,
looking for an external opening that appears as an open sinus or elevation of granulation tissue.
Spontaneous discharge via the external opening may be apparent or expressible upon digital rectal examination.

Digital rectal examination may reveal a fibrous tract or cord beneath the skin.
It also helps delineate any further acute inflammation that is not yet drained.
Lateral or posterior indurations suggests deep post anal or ischio-rectal extension.
Anoscopy is usually required to identify the internal opening.

PARKS CLASSIFICATION:
Defines 4 types of fistula-in-ano that result from cryptoglandular infections.
Intersphincteric
Common course - Via internal sphincter to the intersphincteric space and then to the perineum
Seventy percent of all anal fistulae
Trans sphincteric
Common course - Low via internal and external sphincters into the ischiorectal fossa and then to the perineum
Twenty-five percent of all anal fistulae

Suprasphincteric
Common course - Via intersphincteric space superiorly to above puborectalis muscle into ischiorectal fossa and then to perineum
Five percent of all anal fistulae

Extrasphincteric
Common course - From perianal skin through levator ani muscles to the rectal wall completely outside sphincter mechanism
One percent of all anal fistulae

LAB STUDIES:
Imaging Studies:
Radiologic studies: These are not performed for routine fistula evaluation.
They can be helpful when the primary opening is difficult to identify or
In the case of recurrent or multiple fistulae to identify secondary tracts or missed primary openings.

FISTULOGRAPHY:
This involves injection of contrast via the internal opening, which is followed by anteroposterior, lateral, and oblique x-ray images to outline the course of the fistula tract.
The accuracy rate is 16-48%.
The procedure is well tolerated but requires the ability to visualize the internal opening.
Except in the case of recurrent disease, fistulography may be slightly more useful than a careful examination under anesthesia.

ENDO ANAL AND ENDO RECTAL ULTRA SOUND:
These studies involve passage of a 7- or 10-MHz transducer into anal canal to help define muscular anatomy differentiating intersphincteric from transsphincteric lesions.
A standard water-filled balloon transducer can help evaluate the rectal wall for any suprasphincteric extension.

MRI:
Findings show 80-90% concordance with operative findings when observing a primary tract course and secondary extensions. MRI is becoming the study of choice when evaluating complex fistulae. It has been shown to improve recurrence rates by providing information on otherwise unknown extensions.

CT SCAN:
A CT scan is more helpful in the setting of perirectal inflammatory disease than in the setting of small fistulae because it is better for delineating fluid pockets that require drainage than for small fistulae.
CT scan requires administration of oral and rectal contrast.
Muscular anatomy is not delineated well.
A barium enema/small bowel series: This is useful for patients with multiple fistulae or recurrent disease to help rule out inflammatory bowel disease.

PRACTOSIGMOIDOSCOPY/COLONOSCOPY:
Rigid sigmoidoscopy can be performed at the initial evaluation to help rule out any associated disease process in the rectum.
Further colonic evaluation is performed only as indicated.

OTHER TESTS:
Anal manometry
Pressure evaluation of the sphincter mechanism is helpful in certain patients.
Decreased tone observed during preoperative evaluation
History of previous fistulotomy
History of obstetrical trauma
High transsphincteric or suprasphincteric fistula (if known)
Very elderly patients
If decreased, surgical division of any portion of the sphincter mechanism should be avoided.

Recent studies show that the addition of hydrogen peroxide via the external opening can help outline the fistula tract course. This may be useful to help delineate missed internal openings.
These studies are reported to be 50% better than physical examination alone to help find an internal opening that is difficult to localize.
This modality has not been used widely for routine clinical fistula evaluation.

SURGICAL THERATHY:
The laying-open technique (fistulotomy) is useful for 85-95% of primary fistulae (ie, submucosal, intersphincteric, low transsphincteric).

Perform a biopsy on any firm, suggestive tissue.

Seton placement
A seton can be placed alone, combined with fistulotomy, or in a staged fashion. This technique is useful in patients with the following conditions:
Complex fistulae (ie, high transsphincteric, suprasphincteric, extrasphincteric) or multiple fistulae

HOMEOPATHIC TREATMENT:
FISTULA, rectal (41)
2 aloe, 2 alum, 1 ant-c, 1 aur, 3 AUR-M, 1 bar-m, 1 bell, 3 BERB, 1 bry, 1 cact, 3 CALC, 3 CALC-P, 1 calc-s, 1 carbn-s, 3 CARB-V, 3 CAUST, 2 fl-ac, 2 graph, 2 hep, 2 hydr, 1 ign, 3 KALI-C, 2 kreos, 2 lach, 2 lyc, 2 merc, 1 myris, 3 NIT-AC, 1 nux-v, 1 paeon, 2 petr, 2 phos, 1 puls, 1 querc, 3 RAT, 2 sep, 3 SIL, 2 staph, 2 sulph, 2 syph, 2 thuj

FISTULA, rectal alternates with chest disorders (3)
1 berb, 1 calc-p, 2 sil
FISTULA, rectal itching, with (1)
1 berb
drdevendrakumarmd

Consult drdevedrakumar

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