By: Dr. Hameed H. Alaraji Consultant G. Surgeon Alkindy College Of Medicine



Download 73.61 Kb.
Date conversion13.06.2017
Size73.61 Kb.
THE ANORECTUM


By: Dr.Hameed H. Alaraji

Consultant G.Surgeon

Alkindy College Of Medicine

University Of Baghdad

2014-2015

The anorectum
Learning objectives:

*To understand the anatomy of the rectum & its relationship to surgical diseases and their treatment.

* To understand the pathology, clinical presentation, investigation, differential diagnosis and treatment of rectal diseases.

* To appreciate that carcinoma of the rectum is common and its symptoms are similar to that of benign diseases. So pts with such symptoms should be carefully evaluated.



Anatomy:
*The rectum is endodermal in origin. It is the dorsal part of the cloaca.It begins where the taenia coli of the sigmoid join to form a continuous outer longitudinal muscle at the level of sacral promontory.

*The anorectum is formed from the fusion of the rectum with the anal canal, which occurs at the 8th week of intrauterine life. When the anorectal septum ruptures it leaves the DENTATE LINE as a mark of the fusion.

*The rectum is 12-18 cm long, extending from the rectosigmoidal junction to the anal canal (marked by the passage to the pelvic floor).The rectum lies in the curve of the sacrum forming 3 curves, which in turn create 3 intraluminal semilunar folds known as VALVES OF HOUSTON.

*The proximal and distal curves are convex to the left while the middle one is convex to the right.The middle curve nearly indicates to the anterior peritoneal reflection which is 6-8cm above the anus,here the rectum becomes completely extraperitoneal until it fuses to anus.

*The rectum is divided into three equal parts: the upper is freely mobile and totally covered by peritoneum, the middle third is covered by peritoneum only anteriorly and some of the lateral side while the lower third is not covered by peritoneum and lies deep in the pelvis.

*The lower third of rectum is fixed posteriorly to the sacrum by the presacral (Waldeyer) fascia.laterally by the lateral ligaments and anteriorly by the Denonvilliers fascia which seperates it from the prostate or vagina.


The anal canal:

*The anal canal is an invagination of the ectodermal tissue.

*The anal canal starts at the junction of the rectal mucosa with the anal mucosa forming the DENTATE LINE, and ends at the anal verge which indicate to the junction of anal mucosa and the perianal skin.

*The anal canal is a collapsed anteroposterior slit, 3-4cm long. It is supported by a complex anal sphincteric mechanism composed from the internal and external sphincters.

* The internal sphincter is a specialized continuation of the circular muscle of the rectum.It is an involuntary muscle, normally contracted at rest (i.e: not under control).

*The external sphincter is a complicated functional funnel-shaped muscular structure starting at the level of puborectalis and levator ani muscles and ending caudally at the subcutaneous external sphincter.The external sphincter muscle is voluntary, striated and supplied with somatic nerves (i.e: it is under control).




BLOOD SUPPLY:

1-The main blood supply to the rectum comes from the superior rectal artery which is the direct continuation of the inferior mesenteric artery

2- The middle rectal artery, a branch of the internal iliac artery.

3- The inferior rectal artery, a branch of the internal pudendal artery.


THE VENOUS DRAINAGE:

*The superior hemorrhoidal veins drain the upper half of the rectum the unite to form the superior rectal vein which ascends up to form the inferior mesenteric vein (a part of the portal venous system) which joins the splenic vein.


THE LYMPHATIC DRAINAGE:

In general lymphatic drainage of the rectum is directed upward to the lymphatics around the common iliac arteries and the aorta.But if this pathway is obstructed for any reason then drainage will shift laterally and downward.


CLINICAL FEATURES OF ANORECTAL DISEASES:
Main symptoms:

1- Bleeding per rectum

2- Altered bowel habit.

3- Mucous discharge.

4- Tenesmus.

5- Rectal prolapse.

6- Loss of wt.
Main signs:

These can be elicited by direct clinical examination which includes:

1- Inspection of the anal region.

2- Digital examination.

3- Proctoscopy.

4- Sigmoidoscopy.

Anorectal clinical examination can only be performed when the patient lies in the left lateral or knee-elbow positions.

Rectal injuries:

Rectum can be injured by anyone of the following mechanisms:

1- Falling on a pointing objects.

2- Penetrating missiles (bullet or shell).

3- Sexual assault.

4- During vaginal delivery.


Diagnosis:

1- History is very helpful.

2- Physical examination:

i- Inspection of the anal region (any injury or blood ).

ii- Digital rectal exam(any palpable injury or blood stained index)

3-A water-soluble contrast enema.

4- CT scan with rectal contrast.

Note: Beware that rectal injuries may be associated with urethral or vesical injuries.
Treatment:

*If the diagnosis is confirmed:

-In rectal injuries above the peritoneal reflection so (laparotomy+closure of the injury + sigmoid defunctioning colostomy).

- In rectal injuries below peritoneal reflection perform a thorough perineal debridement and lavage then do defunctioning sigmoid colostomy.

* Give good coverage of antibiotics against aerobic and anaerobic microorganisms.
Foreign bodies in the rectum:

Rectal prolapse:

There are two types of rectal prolapse (mucosal prolapse and full-thickness prolapse):


A- Mucosal prolapse:

This may occur in infants, children or in adults.

Mucosal prolapse in infants is thought to be due to undeveloped sacrum, so the rectum is directed downward which may predispose to such condition.Another etiology is the undeveloped sphincteric mechanism which supports the rectum in place.

In children it may be due prolonged straining in chronic diarrhoea or due to severe malnutrition.Other causes are fibrocystic disease, maldevelopement of the pelvis and neurological causes.

In adults mucosal prolapse is associated with 3rd degree haemorrhoids.Perineal tear during vaginal delivery in females and chronic straining due to urethral obstruction in males also predispose for mucosal prolapse.

In elderly mucosal prolapse is usually associated with atony of sphincteric mechanism.
* The treatment: in infants and children starts by digital replacement of the mucosa up in the anal canal.Continue doing that for at least 6 weeks, if the condition will not improve perform a submucosal injection of 5% phenol in almond oil in a circumferential multiple locations, this will result in an aseptic inflammation and tethering of the mucosa to the muscular layer under it.

Sometimes surgery is indicated: the retrorectal space is entered and the rectum is sutured to the sacrum.



*The treatment in adults is either:

i- Submucosal injection of 5% phenol in almond oil or the application of rubber bands to the redundant mucosa (as we do in hemorrhoids).

ii- Surgical resection of the prolapsed mucosa.
B-Full-thickness prolapse (procedentia ):

Less common than mucosal prolapse.The protrusion consists of all layers of the rectal wall, and is usually associated with weak pelvic floor. It is usually more than 4cm & may reach 10-15cm in length.

On palpation of the prolapsed segment you feel a double thickness of rectal wall (thicker than mucosa).The anal sphincter is characteristically patulous (lax).

Complete prolapse is uncommon in children, but is common in elderly.Women are affected six times more than men & is usually associated with uterine prolapse.In 50% of adult patients it is associated with faecal incontinence.


Differential diagnosis:

1-In children: it should be differentiated from long ileocaecal intussusception.

2-In adults: sigmoidorectal intussusception,

In this case you can pass your finger between the prolapsed mass and the anal wall.


Treatment: is mostly surgical.

Surgery can be performed via perineum or abdominal.



Perineal operations: the most preferred perineal operation is Delorme's operation where the prolapsed mucosa is excised & the muscular layer is plicated.(see text).

Another operation called (Altemeier's procedure): where the prolapsed rectum is excised with end to end anastamosis.



Abdominal approach:

Through laparotomy the prolapsed rectum is pulled up and fixed in its new place.There are different ways to fix the rectum.(see text)




Neoplasms of the rectum:

Either benign or malignant.
1- Benign include: *Adenoma*Papilloma*Lipoma*Endometrioma*Haemangioma

2-Malignant:

-Primary: Adenocarcinoma

-Secondary:metastasis from adjacent organs (prostat,uterus..)


Rectal polyps:
The most common rectal polyps are:

1-Juvenile polyp: found in infants & children. Bright-red pedunculated tumor (cherry tumor).It presents with fresh rectal bleeding usually during defaecation with appearance of the polyp out the anus.It has no tendency to malignant change. Treatment is easy: by clamping &excision.

2-Villous adenoma:has characteristic frond-like appearance.May be very large to fill the rectum.These polyps have great tendency to change into malignant tumor.In rare instances it may cause electrolytes disturbance (hypokalemia) because it secretes excessive amounts of mucous secretions rich with potassium.

Treatment: is by surgical excision as soon as possible.

3-Hyperplastic polyps: small, pinkish, sessile polyps. Are frequently multiple. They are harmless & need no treatment.

4-Inflammatory pseudopolyps: it is not a true polyp but an oedematous mucosa.Its associated with different types of colitis.

5-Familial multiple adenomatous polyposes: Found in adults & is inherited as autosomal dominant character. It is premalignant condition and a total proctocolectomy is required (the anal sphincteric mechanism should be preserved).


In the management of benign rectal polyps follow these principles:

1- Rectum& sigmoid are the most frequent sites for polyps.

2-Adenomatous polyps are premalignant & should be resected soon.

3-When the size of the polyp exceeds 1cm there is greater possibility of malignant change.

4-When there are multiple polyps all should be removed & examined to exclude malignancy. 5-Colonoscopy is mandatory if you suspect more than one polyp to exclude malignancy. 6-No rectal polyp is removed until the possibility of a proximal carcinoma is ruled out.

7-Most polyps can be removed via endoscopic techniques (snaring).



Carcinoma of the rectum:

It constitutes one third of all large bowel carcinomas.Affects both sexes equally.Can occur at any age but mostly between 50-70 year age group.

The predisposing factors include preexisting adenoma, familial adenomatous polyposis and ulcerative colitis.
Macroscopic appearance:

*Ulcerative (the commonest type )

*Papilliferous.

*Annular (stenosing).

*Colloid.
Microscopical appearance:

90% are adenocarcinomas arising from rectal columnar epithelium.

9% are also adenocarcinomas with profuse production of mucous.

1% are anaplastic .without any microscopical differentiation.



Spread of rectal carcinoma:

1-Local spread: to the rectal wall layers and with time to the adjacent organs (prostate, vagina, uterus, urinary bladder or sacrum…

2-By lymphatics: to the regional lymph nodes around the inferior mesenteric vessels, then with time to the iliac lymph nodes, para-aortic lymph nodes, and it may reach the supraclavicular lymph nodes (Trausseous' sign).

3-By blood stream: via the superior rectal venous plexus to the portal vessels then to the liver. The lung is also attacked.

4-Transcoelomic: seeding the peritoneal cavity with or without ascitis.
Staging of rectal cancer (Duke's classification):
Stage-A(Duke's-A):-The tumor is confined to the mucosa and submucosa.

Stage-B(Duke's-B):-When there is invasion of muscular layer.

Stage-C(Duke's-C):-Invasion of the regional lymph nodes.

Stage-D(Duke's-D):- Distant metastasis to the liver.lung,urinary bladder…


TNM staging: (T-tumor N-lymph nodes M-metastasis) (see text)
Grading of rectal carcinoma: according to cellular differentiation:

Grade-1: well-differentiated.10-15% of patients. Prognosis is good.

Grade-11: average or moderately differentiated.60-70% of cases. Prognosis is fair.

Grade-111: poorly differentiated.20-30% of cases. Prognosis is poor.


Clinical features: presentation is usually late (after nearly six months) because early symptoms are insignificant.

i-Bleeding is the earliest and most common symptom.

ii-Feeling of incomplete defaecation(tenesmus).The patient tries to empty his rectum several times a day. This mostly occurs with tumor of lower rectum.

iii-Alteration of bowel habit:Patient may suffer from constipation, or early morning bloody diarrhoea.

iv-Pain:is a late symptom when the tumour causes intestinal obstruction or invades the adjacent organs.

v-Weight loss:this usually occurs when the tumour reaches the liver.


Investigations & diagnosis:

1-Take full history.

2-Abdominal examination: in late stages you may feel an abdominal mass or a palpable liver.

3-Digital rectal examination: you may feel a mass.

4-proctoscopy: If you see the tumour take a biopsy.

5-Proctosigmoidoscopy: for higher tumor, if you see a mass take a biopsy.

6-Colonoscopy (nowadays virtual CT-colonography).
If the diagnosis is confirmed you have to do staging by:

i-CT-chest

ii-CT-abdomen (liver &lymph nodes).

iii-Endoluminal(endorectal)ultrasound to detect any local invasion.


Treatment: Treatment is mostly surgical.The type of surgery required depends on the stage of the tumor and the site in the rectum.

The patient fitness for surgery should be assessed.There are essential steps to prepare the patient for surgery:

1-Bowel preparation.

2-Maping the operation & siting the stoma.

3-Preparation & cross-matching of blood.

4-Prophylactic antibiotics.

5-Prophylaxis against deep vein thrombosis.

6-Insertion of urethral catheter.


When the tumour is resectable curative surgery can be performed via laparotomy or laparoscopic approach.

For rectal cancer located in the upper third, abdominal resection is done with direct anastamosis of the proximal end of the sigmoid to the lower rectal stump.

For tumors located in the lower third abdominoperineal resection with permanent colostomy is indicated.
When the tumour is irresectable a palliative procedure can be done to relieve patient suffering (like doing a colostomy in case of intestinal obstruction).
Radiotherapy can be used pre or postoperatively.

Preoperative radiotherapy is used to reduce the size of a locally invasive tumor (down staging) so that it will be resectable.Postoperative radiotherapy is given to reduce the risk of local recurrence.


Diseases of the anus and anal canal:
Objectives:

*To understand the anatomy of the anus & anal canal & their relationship to the anorectal diseases.

*To understand the pathology, clinical presentation, differential diagnosis & treatment of anorectal diseases.

*To understand that anal diseases are common & their treatment tends to be conservative, although surgery may be required.

*To understand that too aggressive or inappropriate surgery may render the patient permanently disabled.


Examination of the anus & anal canal: The patient should be informed about the examination,he should be relaxed.The examination should be done in a private environment with good lighting.

*Positioning:

-A left-lateral position is desirable in elderly patients & female patients.

-Knee-elbow position is used for younger patients.

-Prone Jack's-Knife position is also used sometimes.
1-Inspection: The buttocks are gently parted to see if any skin lesion.dimple,wart,sentinel tag,prolapsed haemorrhoids…

2-Digital examination: wear gloves, lubricate your index finger.First palpate the soft tissues around the anus for any induration or tenderness and subcutaneous lesions.Then introduce your finger gently and palpate the anterior,posterior and lateral walls of the anal canal.After finishing inspect your finger for any blood,mucus,pus and colour of the stool.

3-Proctoscopy: this procedure allows direct inspection of the anal canal and rectum for any haemorrhoids,tumor,ulcer,polyp…This tool can also be used for minor diagnostic and therapeutic procedures like taking a biopsy from a suspicious mass,or injection of piles with sclerosing agent.

4-Sigmoidoscopy:This procedure should be used to inspect upper rectum to exclude any higher tumors or diseases.
Imperforate anus:

A rare congenital disorder in which the neonate is born without a normal anal orifice. Its either anal agenesis or atresia.Its classified into two types (low and high)depending to the site of rectal termination in relation to pelvic floor.It may be associated with other congenital anomalies.The terminal rectum may communicate to the urethra,vagina or urinary bladder.


Clinical examination & diagnosis:

Inspect carefully the perineum: if you see meconium in the region this will indicate a low type.The presence of meconium in the urine this indicate the presence of a rectourethral or rectovesical fistula.

Examine for any associated congenital abnormalities.At this time the distal limit of rectal gas can be seen by x-ray in a prone lateral position or upside down view.
Treatment:

During the first 24hours supply the baby with IV fluids and antibiotics. Treatment of low type is easy by anoplasty.

For high type perform a colostomy.After several months perform definitive surgery (pull-through surgery).

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


Pilonidal sinus:
Pilus=hair Nidus=nest.

The sinus opening is in the natal cleft. Its either single opening or multiple. Frequently you see a tuft of free hair lying free within the sinus. Features of infection with bad odor are found. Young adults are more affected. Males are affected more than females.

This condition is seen in barbers in the cleft between fingers. They may be found in the axilla, umbilicus, perineum or amputation stumps.
Etiology: It seems that these sinuses are caused by hair implantation in the skin, leading to a foreign-body reaction and produce a chronic infection with tract lined by granulation tissue.
Clinical features: the sinus is asymptomatic until it becomes infected, where you see an abscess or purulent discharge.
Treatment:

*Abscess: this is drained in the usual way.

*Sinus: Surgical excision of the sinus and its trabeculies completely and close the wound or leave it open (according to the degree of infection and the presence of dead &necrotized tissues.

Anal fissure (fissure-in-ano):

Is a longitudinal split or tear in the anal margin which may extend up proximally but not beyond the dentate line.Most of anal fissures occur in the posterior midline.Anterior anal fissure is more common in women.

The main etiology of anal fissure is straining during defecation. While anterior fissures in women are due to vaginal deliveries.

Chronic anal fissures are caused by repeated trauma to the acute fissure and may be less blood perfusion of the posterior commissure.

Anal fissures (especially the chronic one) are either primary or secondary to other diseases like crohn's disease,tuberculosis,malignancy,HIV,syphilitic…etc.
Clinical features:

The condition mainly affect young adults but can occur at any age even in infants.

The acute type presents with severe pain during defecation with a streak of fresh blood on the stool.

The chronic fissure lies between a hypertrophied papillae internally and ended with a skin tag externally.The fissure base is indurated.

Anterior fissures account for about 10% of cases found in women,while only 1% of cases in men (i.e:99% are posterior).

Treatment:

*Confirm the diagnosis & exclude secondary causes.

A- Conservative treatment will heal all the acute fissures & most chronic fissures:-

i-Normalize the bowel habits in a way that passage of stool will be nontraumatic.

ii-Add fibers to diet & advise your patient to take a lot of fluids.

iii-Apply warm paths & local anesthetic agents will relieve pain.

iv- Application of anal sphincter relaxants,so relieving pain & improving blood supply & that will promote healing.Such agents like:Glyceryl trinitrates 0.2% applied 4 times daily or Deltiazem 2% applied twice daily.

B- Operative treatment:

-Partial lateral sphincterotomy.Under GA few fibers of the sphincter are cut.

-Anal advancement flap.UGA fissurectomy is done then a perianal skin flap is rotated to cover the defect.



Haemorrhoids:

( (Greek : Haem = blood Rhoos = flow) Piles…….. (Latin : pila = a ball

The anal continence is controlled by:

1- Anal sphincters.

2- Anal cushions.

The anal cushions are a highly vascular tissue lining the anal canal. Its composed of a network of venous plexus and saccules which drain through the superior rectal vein.This venous complex is supported by smooth muscles.Apposition of these subepithelial cushions is important for continence of gas & fluids.

Haemorrhoids are classified according to their relation to the anal margin into:

a-Internal hemorrhoids :bleeding from congested traumatized anal cushions.

b-External hemorrhoids:is a term applied to some conditions like:perianal hematoma,skin tag of the anal fissure or anal warts.They are not a real hemorrhoids & wrongly called hemorrhoids.
Pathology:

Internal piles (hemorrhoids) are abnormal anal cushions congested as a result of straining on defecation and traumatized and bleed by passage of hard stool so: (NO BLEEDING NO HAEMORRHOIDS).

Increased intra-abdominal pressure for any reason will also lead to congestion of anal cushions e.g. pregnancy, ascites, pelvic tumors and in portal hypertension.

Grading of hemorrhoids:

1- 1st degree hemorrhoids :internal hemorrhoids that bleed but do not prolapse.

2- 2nd degree = :they bleed,prolapse during defecation but reduce spontaneously.

3- 3rd degree = :they bleed,prolapse during defecation outside anal margin but remain prolapsed unless reduced manually by the patient.

4- 4th degree = : Obstructed, irreducible neither spontaneously nor manually.If not treated urgently they will strangulate.
Clinical features:

The chief complaint is anal bleeding (bright-red).This is the only feature of 1st degree piles. But in more extensive piles prolapse and mucous discharge with itching is also present. Prolapsed piles may cause fecal soiling.

Pain is not a feature of hemorrhoids. When there is pain examine for the presence of one of acute painful anal conditions which are:

1- Acute anal fissure.

2- Perianal hematoma.

3- Perianal or Ischiorectal abscess.

4- Tumor of the anal margin.

5- Proctalgia fugax: Episodic idiopathic attack of pain relieved by anal dilatation.


Examination & diagnosis:

1-Examination of the abdomen for any abdominal mass,enlarged liver or gravid uterus.

2-Inspection of the anal region for any blood or prolapsed piles.

3-Palpate the perianal region for any tender lesion or opening.

4-Digital rectal examination(P/R):piles are not palpable but examine for any palpable lesion in the rectum.Prolapsed piles are obvious.

5-Proctoscopy(by anoscope)to visualize any internal piles. When the patient is in the lithotomy position they usually lie in the 3,7,11 o'clock.

6-Sigmoidoscopy:to visualize any lesion or tumor in the high rectum e.g:polyp,tumor…

7-In few cases you may need to do colonoscopy or barium enema if another condition is suspected.


Complications of untreated haemorrhoids:

1-Anemia.

2-Thrombosis.

3-Obstruction & strangulation(surgical emergency).

4-Ulceration.

5- Gangrene.

6-Portal pyemia (very rare).
Treatment of haemorrhoids:
The first step is to exclude any predisposing factor that may lead to secondary hemorrhoids like rectal tumor or portal hypertension.
*Conservative management:Normalizing bowel habit by:

- Defecation should be attempted only when there is natural desire.

- Adoption of a defaecatory position that minimize straining.

- Adequate fluid intake

- Using certain creams & suppositories are sometimes useful.
*Sclerotherapy:

Applicable for 1st & 2nd degree haemorrhoids.

Injection of 2-3mls of 5% phenol in almond oil(دهن اللوز )above each pile in the submucosa around veins.This injection is painless because its above the dentate line.

Sometimes you may need to repeat the injection at 4-6 weeks intervals.


*Banding:

By using a special bander device a fine circular rubber band is applied to the root of the pile leading to strangulation , sloughing & fall down of the pile.Its also fit for 1st & 2nd degree piles


*Surgical excision (haemorrhoidectomy):

Can be done under local, spinal, caudal or general anesthesia in the lithotomy position. Each pile is dissected transfixed,ligated and excised separately.

Surgery is usually suitable for 3rd degree & 4th degree piles.

The main complications of haemorrhoidectomy are:

1-Acute retention of urine: simple & transient.

2-Postoperative hemorrhage: may be severe enough to cause shock.Is either due to slipped ligature or secondary due to infection.

3-Stricture: this is a late complication occurs when the surgeon excise most or all the anoderm leading to post-healing fibrosis.
Thrombosed pile (perianal hematoma):

This external pile presents as a sudden onset,olive-shaped,painful blue subcutaneous swelling at the anal margin.Its caused by straining at stool,forceful coughing or lifting heavy weights leading to bleeding and thrombosis of superficial veins.


Treatment: In the acute phase incision and evacuation of a small hematoma is curable.

Untreated it may resolve, suppurate, burst, or fibrose giving rise to a skin tag.




Anorectal abscess:

Is a common surgical emergency.More common in men than women.The source of infection may be from the skin or infected anorectal glands.Patients with diabetes mellitus or AIDS are more affected.


Anorectal abscesses are classified to:

1-Perianal.

2-Submucous.

3-Ischiorectal.

4-Pelvirectal
Treatment:Is surgical drainage as early as possible to prevent formation of a fistula.
Fistula-in-ano:

A fistula is:an abnormal communication between two epithelial surfaces.



Fistula-in-ano is an abnormal tract lined by granulation tissue between the anorectal canal and the perianal skin.

Aetiology: The great majority result from initial abscess of anorectal gland that penetrates the mucosa to open in the lumen(internal opening) and to the skin (external opening).This is nonspecific or idiopathic.But diseases like Crohn's disease,tuberculosis,actinomycosis and malignancies may be the cause behind fistula development.
Clinical features: The patient usually gives a history of anorectal abscess which continues discharging leaving a persistent opening with recurrent episodes of discharge.Examination reveals the external opening of a fistula.The internal opening may be felt by digital rectal examination or by probing of the fistula under anesthesia(don't probe the fistula without anesthesia).In some cases its difficult to detect the exact anatomy of the tract.In such cases perform endoanal ultrasound or MRI to demonstrate the fistula clearly.Its more common in men especially in their 30-50years age.
Classification of fistula-in-ano:

They are classified according to their level and their relation to anal sphincters.

1-Superficial :which include:

i-Submucous

ii-Subcutaneous
2-Low anal:where the fistula track is below the anorectal ring.these include:

i-Intersphincteric

ii-Trans-sphincteric
3-High anal:includes:supra-sphincteric fistulae,Are close to the anorectal ring.

4-Pelvi-rectal fistula.are rare and extend above the anorectal ring.


Goodsall's rule:

Fistulae with their external opening located posterior to anus usually open in the midline inside the anus,while those with external opening located anteriorly will open directly in the anus.



Treatment:

Careful assessment of the anatomy is essential.Treatment is always surgical.

Treatment in superficial and low anal fistulae is Fistulotomy(laying the fistulous track opened).There is no fear of sphincteric injury.

In high anal fistulae there is great danger of sphincteric injury,so do Fistulotomy for the low part(below the anorectal ring) and insert a nylon thread(seton) in the remaining upper part to induce fibrosis of the track.Another stage of surgery is usually required to open this part.This procedure will avoid the development of faecal incontinence.

Nowadays researches are running to use a special type of glue that plugs the fistulous track and allowing growth of healthy tissue instead of infected granulation tissue inside the fistulous track.
Anal stricture:

Etiology:

i-Congenital.

ii-Traumatic or iatrogenic: as after hemorrhoidectomy or lacerating trauma.

iii-Inflammatory: ulcerative colitis, crohn's disease, and lymphogranuloma inguinale.

iv-Post-irradiation.

v-Infiltrating malignancy.


Treatment of benign stricture may be by frequent dilatation(conservative) or surgical by anoplasty(if conservative trials fail).

If malignancy is the cause excision of anorectum may be required.


Malignant lesions of the anus and anal canal:

Usually rare (2%of all malignancies of the large bowel).

Those arising below the dentate line are usually squamous, while those above it are called basalloid or transitional (squamous & basalloid tumors are both called epidermoid tumors to differentiate them from rectal tumors (adenocarcinoma, melanoma, lymphoma…

Squamous cell carcinoma is found in patients with Immunosuppression(HIV, renal transplant and viral hepatitis. Perianal papillomas can change in the long-term to SCC.

The patient presents with pain & bleeding. Mass, pruritus or discharge are less common. Advanced tumors may cause faecal incontinence, or may invade the adjacent tissues e.g: anal sphincters. In women it may fistulize to the vagina. There may be a palpable indurated tender ulcer.
Management:

Small early cancers can be excised(with or without chemoradiotherapy) and followed.



More advanced cancers need preoperative chemoradiotherapy to reduce their size & stop invasion then surgical excision.Proximal defunctioning colostomy may be required.





The database is protected by copyright ©ininet.org 2016
send message

    Main page