Fissure in ano.
Dr. Barin Bose MS, FACRSI, FAIS.
Consultant Surgeon and Coloproctologist.
An anal fissure is a linear ulcer in the lower half of the anal canal and extends from just below the dentate line to the margin of the anus (anal verge). The ulcer may be acute, recurrent or chronic and may occur alone or with other rectal disease, most commonly haemorrhoids.
An anal fissure is one of the chief causes of anal pain, in the acute case it is severe enough to incapacitate the patient. In fact it is a disease of the anus which causes an amount of suffering out of proportion to the size of the leson. It is common in both the sexes and is encountered in young or middle aged adults, but is sometimes seen at other ages including infancy and early childhood.
Aetiology – Trauma to the anal canal is the most common initiating factors usually in the form of passage of a large hard fecal mass.
Among the predisposing factors are –
Pathophysiology - An anal fissure is typically found in the posterior midline just within the anal verge. More than 98% of fissure in males and nearly 85% in females occur in this way. The superficial external anal sphincter arise from the tip and side of the coccyx and surrounds the anal canal leaving a weak area on the posterior wall this causes it to tear when it is over stretched during the passage of a hard stool. In addition, anal crypts are more marked posteriorly and which tends to harbour subclinical infection, which causes the epithelial lining to be friable. Anterior fissure in women (15%) is often due to trauma of parturition causing old tear to break down.
An acute fissure is an ulcer, the base of which is formed by longitudinal muscle fibres. When it become chronic , the deeper circular fibres of the internal sphincter are seen to form the floor of the fissure. The changes which develops in a chronic fissure are -
· Thickening of the edge of the ulcer.
· Develpoment of an oedematous tag of skin at its lower end (sentinel piles)
· Hypertrophy of the anal papilla at its upper end .
The sentinel piles develops due to combination of infection and oedema.
A chronic fissure thus has four typical features -
(1) A boat shaped ulcer with indurated edges.
(2) Fibres of internal sphincter forms the floor.
(3) A rounded swelling (hypertrophid anal papilla) at its upper end.
(4) A tag of skin at its lower end (sentinel piles).
Infection of the base may lead to an abscess, which may rucpture through the base of the fissure or through the skin near by leaving a short subcutaneous fistula.
An anal fissure situated away from the midline usually has a cause within the anal canal in the form of a fibrous polyp , large haemorrhoids or a hypertrophid anal papilla.If a cause is not found , such a fissure should immediately raise suspicion of another pathology ( example – tuberculosis, syphilis, leukaemia, squamous cell carcinoma or inflammatory bowel disease especially Crohn’s disease. Fissure in inflammatory bowel disease tends to be multiple, broad and situated away from the midline. The spasm normally associated with a nonspecific fissure is minimal or abscent.The possibility of such fissure must be borne in mind since operative interference may cause delay in wound healing or an early recurrence.
Certain pathological changes in the internal anal sphincter results due to an anal fissure . The spasm of the internal sphincter may prevent its healing by approximating the edges of the ulcer and preventing adequate drainage.The resulting pressure with the internal sphincter is higher in patients with an anal fissure than normal controls. Normally rectal distension causes a reflex relaxation of the internal sphincter and contration of the external sphincter. In patients with fissure this relaxation of the internal sphincter is followed by an abnormal contration . Following successful treatment this abnormal contration of the internal sphincter disappears.
Diagnosis - Pain of tearing, cutting or burning type associated with defecation and lasting for a variable period after defecation is the symptom. With the onset of suppuration the pain become throbbing in character and continuous. Each act of defecation become an agony due to fear of pain the act of defecation may be postponed leading to constipation. A vicious cycle of pain, constipation and pain is setup. Bleeding is seldom more than a few drops and is bright in color.Streaks of blood may be seen on the stool surface. In an acute fissure, reflex symptom of dysuria or pain radiating down the thighs is common. In chronic fissure , irritation and discharge which soils the underclothing are present . A swollen skin tag be felt outside the anus (sentinel piles).
Examination should be done very gently since hurry or initial crudeness on the part of the examiner may make subsequent examination difficult or impossible. Gentle traction on the anal margin along with a request to bear the discomfort will show the lower end of the fissure.In chronic fissure the presence of a sentinel piles is noted. Applying a local anaesthetic ointment to the fissure is important before doing a rectal examination. An acute fissure being a shallow ulcer is impalpable, though the sphincter spasm is marked.Proctoscopy is avoided in these cases. A chronic fissure is felt as an indurated ulcer, but the sphincter spasm is variable . A hypertrophid anal papilla may be felt at he upper end of the fissure in a chronic case. Gently proctoscopy will show the presence of associated haemorrhoids,hypertrophid papilla or a fibrous polyp. Sigmoidoscopy is not essential for the diagnosis but must be done after acute symptoms have subsided or before surgery to rule out inflammatory bowel disease or associated pathology.
Differential Diagnosis – A typical history of pain at defecation, a few drops of bright red blood and an ulcer in the posterior or anterior midline clinches the diagnosis in most instances.
An ulcer situated away from the midline should immediately arise suspicion of –
· A traction fissure, the cause of which lies within the anal canal is excluded by digital and proctoscopic examination.
· A tuberculous ulcer has undermined edges and the discharge is thin and watery. The presence of a lesion in the chest, a raised ESR, sputum examination and a biopsy may be necessary to reach a diagnosis.
· A primary chancre has a good deal of induration along with inguinal lymphadenopathy. Secondary syphilis presents as multiple fissure. The Wassermann reaction is strongly positive.
· A malignant ulcer has indurated and raised edges and is resistant to the local treatment . Biopsy is needed for the diagnosis.
· Fissure in inflammatory bowel disease are multiple, indolent and resistant to local treatment. Proctoscopy and sigmoidoscopy reveals the pathology within the rectum. Sometimes the fissure is present before appearance of bowel disease especially Crohn’s disease.
· Multiple acute fissure may occure following sodomy in which a history of anal intercourse can be obtained. Possibility of HIV infection being transmitted through this route should be kept in mind.
· Idiopathic stenosis of internal sphincter – It occur in certain older patients usually women, who have been accustomed to taking aperients over many years so that the anal canal has for a long time been spared the regular dilation action of a normal solid motion. As a result the internal sphincter undergo contration and may become fixed in this contracted condition by fibrosis.There may be no symptom or when the contraction become extreme, the patient may find difficulty in passing motions. The condition is easily recognized by finding a tight contracted internal sphincter on palpation, without any evidence of a past or present fissure. It is treated by internal sphincterotomy exactly as for chronic anal fissure.
Treatment – Many fissure heals spontaneously in two or three weeks. These are usually superficial lesion which have been attended by a short history.of pain. In contrast a chronic fissure are most resistant to any form of conservative treatment, though there may be temporary releaf of symptoms, but the trouble tends to recur frequently. To save the patients unnecessary discomfort it is desirable to make an early decision as to whether a fissure is likely to heal under a conservative regimen or whether an operation will be required.
Features indicating chronicity and the need for operation – A long continuous or intermittent history of pain obviously suggests a chronic lesion is present. On examination the findings that indicate chronicity are a large sentinel tag of skin, induration on the edge of the fissure and the exposure of the internal sphincter in the floor of the fissure. When these signs are present a lasting cure is unlikely to be achieved without operation. A recent fissure of a more superficial character, operative measure may sometime be required because of the pain which the patient is unwilling to tolerate any more or because of abscess or fistula formation.
Conservative Treatment - Treatment of acute anal fissure is nonsurgical unless the fissure is due to traction when excision of fibrous polyp or the anal papilla will remove the chance of its recurrence.
Conservative measures include avoidance of constipation by means of mild laxatives to enable the passage of soft stools. Repeated anal trauma by passage of hard faeces can be avoided by laxatives such as liquid paraffin are especially suitable for they tend to produce soft easily passage motions. Drastic purgation must be avoided since frequent passage of loose stools causes agony.
Surface anaesthetic ointment ( 5% Xylocaine) and oral analgesics are helpful to reduce pain.
Metronidazole and a suitable broad spectrum antibiotics will hasten recovery.
Frequent Sitz bath are comforting and help to reduce the sphincter spasm.
Use of anal dilator , which was recommended by Gabriel in 1948 seem to have no convincing rationale for its use, in fact it seems illogical to advise dilatation of the anus in this painful condition.It is however a simpler and more reliable way of applying an anaesthetic ointment , than by digital insertion.
Injection of long acting anaesthetic agents into the sphincter muscles has been given up because of the danger of abscess formation.
Medical management of fissure in ano - The object of medical management are –
· Relief of pain.
· Complete relaxation of the internal sphincter.
· Healing of the fissure.
The general measures to releave pain are –
(1) Adequate fluid intake.
(2) Fibre rich diet. A diet should be rich in vegetables, fruits and brown rice.
(3) Bulk forming agents like psyllium husk and bran can be given after meals.
(4) Stool softners and laxatives like lactulose enables the passage of soft stool.
(5) Local anaesthetic agents – Lignocaine 5% ointment applied half an hour before defecation can be used to alleviate the pain during passing of stools.
(6) Sitz bath – Frequent sitz bath help to reduce the sphincter spasm.
Medical management of acute fissure in ano – Is by using an agent which produce relaxation of internal sphincter, this process is known as “Chemical Sphincterotomy” .Some of the agents used for chemical sphincterotomy are –
· Glyceryl trinitrate .
· Calcium channel blockers.
· Botulinum toxin.
Glyceryl trinitrate – It is a vasodilator and smooth muscle relaxant. It releases nictric oxide which is an inhibitory neuro - transmitter. The drug is used as 0.2% cream applied locally to the anal canal BD or TDS for 6 to 8 weeks. Glyceryl trinitrate dermal patch has also been used . When applied as an 0.2% ointment to the anal canal produce sufficient relaxation of the sphincter to allow the fissure to heal in upto two third of patients. In addition glyceryl trinitrate being a vasodilator improves blood flow to the area and this aids healing. Unfortunately glyceryl trinitrate ointment may produce severe head ache.
Isosorbide dinitrate – As 1% ointment has also been used in past to produce chemical sphincterotomy but again it has head ache a prominent side effect.
Calcium Channel Blockers – Like Nifedipine and Diltizem – are antihypertensive vasodilators and act by blocking the transport of calcium. Nifedipine given orally as 20 Mgs BD or applied as 0.5% cream BD for 4 to 6 weeks . Diltiazem given 60Mgs BD as oral form or applied as 2% cream BD for 4 to 6 weeks. Local application are better than oral medications.Side effect are headache, postural hypotension and perianal itching.
Botulinum Toxin – It is a striated muscle relaxant and acts by inhibiting acetylcholine release at the neuromuscular junction. 30 units of Botulinum Toxin A injected into the internal sphincter on either side of the fissure once a month. The average healing rates of 47 to 65% has been reported . Local side effects of flatus incontinence, increase in residual urine, muscle weakness, fecal soiling have been seen.
Newer Agents Like –
Have been used but none have gained importance.
Some of the obsolete agents and methods are –
Acute fissure in Ano – Most can be managed by general measures. Adequate fluid intake. Fibre rich diet. Bulk forming agents, bran is better than others. Local anaesthetic agents, Sitz bath. Combination of modalities work better. Local pain relief is best achieved with Glyceryl trinitrate .
Chronic fissure in Ano – Chance of cure is approximately 50%. Studies carried out with Glyceryl trinitrate verses Calcium Channel Blocker versus Botulinum Toxin has shown that efficacy is almost equal in these three agents .But side effects is more with Glyceryl trinitrate.
Medical management should be offered as initial treatment option. Recurrences should be managed surgically.
In Conclusion - Acute fissure in ano should be managed medically. Chronic fissure in ano has a 50% chance of cure by medical management and hence should be attempted first.
Irrespective of the approach to treatment , every patient , physician and surgeon should accept the validity of the concept that when pain resulting from anal fissure is intolerable, when the fissure has been unresponsive to nonoperative management , when fissure has been present from a long time or when the fissure recurs after nonoperative management - an operative approach is indicated.
Operative Treatment - A large sentinel pile with induration of the edges of the ulcer, exposure of the internal sphincter fibres in the floor and the presence of hypertrophid anal papilla are indication for operation. A large haemorrhoids, fibrous polyp or a subcutaneous fistula make it unlikely that treatment other than surgery is going to be useful.
Though there is a considerable divergence of opinion as to the essential steps in the operative treatment of anal fissure – whether it is correction of spasm of the internal sphincter muscle by stretching or by partial or complete division, or excision of the fissure so as to provide a wide external wound in which discharge cannot collect.
The aim of the surgical treatment is to modify the function of the internal sphincter so that it cannot go into spasm and to increase the diameter of the anal canal outlet so that it would offer less resistance to the passage of stools. This is done by stretching of the anal canal or partial or complete division of internal sphincter muscle.
Stretching of the anal outlet as advocated by Recamier, is used in acute fissure when there is no response to conservative treatment.The procedure should be done under general anaesthesia .It involves gradual stretching of the anal sphincters over several minutes to effect a temporary paralysis of the internal and external sphincter muscles for several days to week thus allowing the ulcer to heal. There is no anal wound and the patient can return to work the next day. Recurrence varies from 5 to 15 % and a minor degree of disturbance of anal control is likely , especially in the elderly patients. Due the risk of incontinence following the procedure , have now made it unpopular. Stretching should not be done in the presence of a traction fissure or in a fissure associated with large internal haemorrhoids since a prolapse of the haemorrhoids often follows the procedure.
The classic operation of Gabriel removes the fissure along with a triangular area of skin and adds a sphincterotomy in the posterior midline. The result is a large wound which takes a long time to heal,though the recurrence rate is small
(1 to 2%) and the patient needs hospitalization for one week. The procedure does not have many supporters.
Internal sphincterotomy was first advocated by Eisenhammer. The sphincter is divided in its lower half in the posterior midline through the fissure itself. The posterior wound thus created takes a long time to heal resulting in a key-hole deformity.
Recently the sphincterotomy performed laterally and the full thickness of the muscle is divided in its lower half. It can be done by the subcutaneous technique, under local or general anaesthesia, the procedure is known as
closed subcutaneous lateral internal sphincterotomy. The fissure need not to be treated though a large sentinel pile or a prolapsed hypertrophied anal papilla should be removed. There is little post operative discomfort and the wound heals quickly . Complications include haemorrhage, perianal abscess formation and a minor degree of loss of anal control.