Surgery: 4th Stage
TUCOM
Dr. Hamid Hindi
ANAL CANAL
Surgical anatomy:
• The anal canal co commences at the level where the rectum pass through the pelvic
diaphragm and end at the anal verge:
1. Anorectal ring.
2. External sphincter.
3. Internal sphincter.
4. Intersphenicteric space.
5. Dentate line.
Anorectal ring:
• Marks the junction between the rectum and anal canal. It is formed by the joining of
the puburectalis, deep part of the external sphincter, and the highest part of the
internal sphincter.
External sphincter:
• It forms the bulk of the sphincter complex and its divided into three parts;
subcutaneous, superficial, and deep. It is voluntary muscle with somatic innervation
by the pudendal nerve. Is has a red color.
Internal sphincter:
• It is the thickened, distal, 4cm of circular muscle coat of the rectum. It is involuntary,
and innervated by the autonomic nervous system.
Intersphinecteric space:
• It is located between the external sphincter and the internal sphincter and it
represents a potential space for extension of perinatal infection because it contain
the blind ends of the anal glands.
Dentate line:
• It is the line which separates the anal canal into upper and lower parts. The upper
part is lined by mucosa which is innervated by autonomic nerve supply, while the
lower half is lined by a sensitive squamous epithelium (somatic innervation).
Blood supply:
• It is by the superior, middle, and inferior rectal vessels
Lymphatic Drainage:
• The upper half is to lymph nodes along the inferior rectal vessels, while the lower
half is to the inguinal lymph nodes.
Diseases of the anorectal region and anal canal:
Imperforated anus:
• It is a rare congenital disorder and is divided into high and low types, depending on
the level of termination of the rectum in relation to the pelvic floor.
• The high type: it is difficult to be corrected and needs multistaged operations it is
prone for Faecal incontinence.
• The low type: it is relatively easy to be corrected and it is prone for chronic
constipation due to anal stenosis after surgical correction.
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Surgery: 4th Stage
TUCOM
Dr. Hamid Hindi
Post anal dermoid:
• It is located in the space anterior to the sacrum and coccyx and is a cystic lesion. It
usually remain asymptomatic until adulthood when it became prone for infection.
Large cystic lesion may present as difficulty in defecation. It should be differentiated
from the anterior sacral meningocele which enlarge when the child cries and is
frequently associated with paralysis of the lower limb and incontinence.
• Rx:- is by surgical excision.
Pilonidal sinus:
• It describes a condition found in the natal cleft overlying the coccyx, consisting of
one or more, usually noninfected midline opening which is communicating with a
fibrous track lined with granulation tissue and containing hair lying loosely within the
lumen.
• Pathology and etiology:
-
Congenital theories.
-
Acquired theories: which is more accepted than congenital one. It is thought that
combination of buttock friction and shearing forces in that area allows shed hair
and broken hair which have collected there to drill through the midline skin, or
that infection in relation to hair follicle allow hair to enter the skin by the suction
created by movement of the buttocks, so creating a subcutaneous, chronically
infected midline tract.
• Clinical features:
-
Males more than females.
-
Intermittent pain, swelling, discharge at the base of the spine due to infection.
-
Frequent attacks of abscess formation.
-
Single or multiple openings at the subcutaneous regions.
• Treatment:
-
Conservative treatment: which is appropriate for minor sinuses, include; cleaning
of tract and removal of all hairs, regular sheaving of the area, strict hygiene, and
ABs cover may be used.
-
Surgical treatment:
1. Open method: by excision of the sinus. Leave the wound opened to heal by
granulation tissue. It carries the lowest recurrence rate, but long time of
healing.
2. Closure of the wound after excision of the sinus.
-
Excision with closure at the midline.
-
Flap closure:
1. Bascoms procedure.
2. Z-closure.
3. Karydakis procedure.
4. Rhomboid flap.
-
It leads for short period of healing but with higher rate of recurrence.
Anal incontinence:
• Causes:
A. Congenital / childhood:
1. Anorectal anomalies.
2. Spina bifida.
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Surgery: 4th Stage
TUCOM
Dr. Hamid Hindi
3. H-S disease.
4. Behavioral.
B. Acquired / adulthood:
1. DM, CVA, MS.
2. Parkinons disease.
3. Spinal cord injuries and other neurological disorders.
4. GIT infections.
5. IBS, megacolon, anal trauma.
6. Abdominal surgery (colonic resection).
7. Pelvic surgery (anterior resection).
8. Pelvic malignancies.
9. Pelvic radiotherapies.
10. Rectal prolapse.
11. Anal surgery (hemorrhoidectomy, fistula surgery, fissure surgery).
12. Obestetric events (labour).
C. General factors:
1. Aging, obesity, psychological diseases,
2. Drug induced (laxative).
• Treatment:
-
Conservative treatment: which includes stool bulking or constipating agents,
bowel retraining and anal plugs which expand within and thus seal the anal
canal. If fail go to the surgical treatment.
-
Surgical treatment:
1. Reunite divided sphincter muscles.
2. Reef external sphincter and puburectalis muscles.
3. Augmentation of anal sphincter by muscle transport flaps (G.M. transport), or
gracilis muscle transport.
4. Artificial bowel sphincter by using of inflatable cuff around anal canal.
5. Colostomy for uncontrolled cases.
Anal fissure:
• It is a longitudinal split in the anoderm of the anal canal which extend from the anal
verge towards, but not beyond the D.L. (Dentate line).
• Causes:
-
Strained evacuation of a hard stool (commonest).
-
Repeated passage or diarrhea (less common).
-
Vaginal delivery (anterior fissure).
-
Vascular insufficiency due increase tonicity of anal sphincter lead to impaired
healing of anal fissure.
• Pathology:
-
Posterior anal fissure (90%).
-
Anterior anal fissure (10%) ( females > males).
-
Acute anal fissure with little fibrosis and no skin tag.
-
Chronic anal fissure with marked fibrosis and tags around the fissure.
• Clinical features:
-
Severe pain on defecation.
-
Bright red bleeding.
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Surgery: 4th Stage
TUCOM
Dr. Hamid Hindi
-
Mucous discharge.
-
Constipation with megacolon especially in children.
• Treatment:
-
Conservative treatment: include the following:
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