ANAL FISSURES

Anal fissures are superficial anal ulcerations apparently linear but actually triangular or oval, accompanied by pain and contracture of the anal sphincter muscles.

The anal fissures occur in the distal portion of the anal duct, from the border of the anal orifice inwards, where it initially affects solely the epithelium and later on involves the whole depth of the anal mucosa.

The anal fissure is most frequently encountered in hemorrhoid patients, in patients suffering from chronic constipation as well as in patients with local or vicinity disorders.

The disorder is more frequent in adults and especially in women; 90 % of fissures are posterior, corresponding to the coccyx.

How do anal fissures occur ?

Anal fissures occur due to various trauma exerted on a fragile anal mucosa. Over 90% of fissures are located at the posterior comissura, which is the weakest anatomical point.

It seems that the triggering factor is most likely the trauma exerted by the passage of tough or large sized feces ejected suddenly or by frequent defecation, as in diarrheas.

The diets poor in vegetal fibers (fruits, vegetables, cereals) is quite frequently associated with anal fissures (since such diet favors constipation). There is no profession imposing higher risks for anal fissures.

Previous history of anal surgery might become a predisposing factor, since the post-surgical scar formation may induce either the stenosis or the lack of elasticity of the anal orifice, thus more susceptible to crack to the trauma represented by a more difficult defecation. There are also known medically induced anal fissures (as a result of a improper medical examinations or maneuvers), following aggressive digital rectal examinations or enema.

It is most likely that minor ulcerations of the anal mucosa often arise from the passage of tougher feces but in most cases such ulcerations heal rapidly and spontaneously, without any long-term complications. However in patients with preexisting abnormalities of the internal sphincter such trauma may progress from acute to chronic fissures.

The most frequent abnormality is the hyper-tonus and the hypertrophy of the internal anal sphincter leading to increases in the resting pressures within the duct and sphincter.

The local trophicity disorders resulting from a faulty blood supply at the comissura – most frequent with hemorrhoid disorders – might also contribute to the occurrence of anal fissures in these areas, are quite frequently associated to haemorrhoidal disorders.

The disorder typically debuts following a constipation episode which cracks the border of the anus, denudating the nervous fillets which are frequent in this area.

As a result, there comes pain, later accompanying all defecations since the already-traumatized region is further injured by the passage of feces.

The internal sphincter becomes more spastic following the passage of feces due to the passage injuring the naked nerve fillets, stimulating the reflex, involuntary contraction of the internal sphincter muscle, leading to two distinct effects.

First of all, the spasm itself leads to pain, and secondly, the spasm further reduces the blood flow towards the posterior region and implicitly towards the fissure, which decisively to a more modest healing process.

This creates a vicious circle decisive for the evolution of the chronic anal fissures, which makes impossible the spontaneous healing.

The anal fissure is located at the posterior region of the anal duct in 90 % of all cases (towards the coccyx) but can also be located elsewhere (anterior, more laterally). Though they are generally unique, there might happen (especially in women) to be double ("bipolar") or multiple fissures.

The anal fissure represents a solution of continuity, a rupture of the musculo-cutaneous layer of the border of the anus, most frequently oval, triangular or shaped as a rocket.

The average anal fissure usually sizes up to 1 cm in length, up to 3-5 mm in width (basal) and about 2-3 mm in depth.

Schematically, the fissures may be classified as simple, young fissures ("fissurettes"), evolved or complete fissures and older, complicated, “aged” fissures.

At first in the young, simple fissures the quite superficial ulceration has a flat red background covered with a fine granular tissue.

In time, in the following stages, the ulceration grows in depth progressively, sometimes revealing the muscular fibers of the internal sphincter. In more advanced stages there may be a fibrosis of the sphincter or an atone ulceration. In time the borders of the fine, right, abrupt ulceration encountered with simple fissures become, in older, complicated fissures, thicker and decollated for 2-3 mm on both sides of the ulceration.

The pain in anal fissures most frequently occurs in three steps.

Following the first feeling of pain throughout defecation (first stage), there comes a short silent interval ("silent stage " – second stage). Following a few minutes of calm, the third stage starts with intense pain, feeling like a burn, ulceration or sting usually lasting for several hours.

These symptoms are unavoidably repeated after every defecation and sometimes become so painful that the patients, connecting the pain to the defecation, repeatedly inhibit their defecation reflexes fearing the pain, thus developing constipation. The constipation further represents a contributing and aggravating factor for the fissure, mostly due also to the fact that at the beginning the pain is more intense as the fissure is established.

Fearing the pain and constipation the patients sometimes refuse to feed themselves enough, which may lead more or less to denutrition (weight loss).

About 70% of patients note the red blood stains on their feces or on the toilette paper. Occasionally several drops of blood may be noted in the toilette seat, but significant bleedings are exceptional in this disorder.

Evolution and complications

Anal fissures usually follow several stages of evolution:

1. Recent fissures (acute)
       Usually exhibit a brutal debut, their occurrence being most often related to the expulsion of difficult feces increased as size or consistency. The pain in recent fissure is characterized of a specific rhythm “in 3 stages”: painful defecation sometimes with minor bleedings, followed by several minutes of calmness and later on by intense pain lasting for several hours. The contraction of the sphincter is visible, palpable and raises the contraindication for digital rectal examination.
        The spontaneous evolution is variable: the sphincter contracture usually prevents scarification, and every defecation induces new injuries; even if scarification occurs, the recurrences are extremely frequent. Most often the symptoms gradually change and the fissure becomes chronic.

2. Chronic fissure
        The pain becomes less intense and lasts shorter, while the contracture is also lesser or even absent; the digital rectal examination becomes possible and even permits passage for small caliber anuscopes. The fissure borders are thicker and decollated, especially in the posterior region, forming a small marisca erroneously referred to sometimes as the "sentinel hemorrhoid". Also at the internal pole from the inside of the anal duct there may be a hypertrophic papilla which may sometimes reach an important size.

3. Infected fissure
       This is the last evolutive stage. The base of the ulceration is covered by an inflammatory granuloma more or less suppurated and sometimes a superficial fistula may be noted.
       Most often however the suppuration may be depicted as a denudated sub-mucous abscess, atone and exhibiting no intention towards scarification.

4. Pre-fissure stage
       At the opposite pole of chronic fissures there may be a pre-fissure stage as small superficial erosions resulting from the passage of tougher feces.
      The pain, more frequently felt as a burn, only occurs at the passage of feces, sometimes being accompanied by minor rectal bleedings.