An anal fissure is a linear tear in the skin of the anus, which occurs mainly after a large and hard bowel movement. However, it can also occur after diarrheal bowel movements, or in the context of inflammatory bowel disease (image 1).
The cause of stretch marks is reduced blood flow to the skin of the anus, combined with hypertonicity of the internal sphincter.
The patient feels an intense sharp pain, which he describes as a knife-like cut, during defecation, which can last from a few minutes to several hours after defecation. This pain prompts the patient to hold back his bowel movements, resulting in constipation, which worsens the pain during subsequent bowel movements. In addition to the pain, there is also slight bleeding during defecation.
Stretch marks are of 2 types:
1. Acute Fissure: is usually of less than 8 weeks duration and is characterized by clear boundaries and a reddish or slightly bloody base.
2. Chronic Fissure: is usually the fissure that persists beyond 8 weeks and is characterized by raised and fibrous boundaries, while at the base the whitish muscle fibers of the internal sphincter are clearly visible.
The tear is located in the midline, at 6 or 12 o’clock when the patient is in the gynecological position. Stretch marks that appear outside the midline should raise the suspicion of another disease, such as neoplasm, inflammatory bowel disease, syphilis, tuberculosis, trauma, or HIV infection.
Many times the fissure is accompanied by a hemorrhoidal nodule, or a hypertrophic papilloma located deeper in the anal canal.
Diagnosing a fissure is usually easy with a simple examination of the perianal area.
Treatment of a tear is initially conservative and includes:
1. Changing dietary habits, with a diet rich in fiber and good hydration, in order to improve the frequency of bowel movements and the texture of the stool.
2. Using topical ointments that reduce the hypertonia of the internal sphincter. These are ointments that contain glyceryl trinitrate (GTN) or diltiazem. GTN ointments have headache as their main side effect, have a success rate of 73% and a recurrence rate of 32%. Diltiazem ointments do not have any side effects and the success and recurrence rates are 80% and 12.5% respectively. In general, these ointments are more successful in acute stretch marks (>80%), while in chronic stretch marks the success rate decreases dramatically (~60%).
3. Botox.
Botox injection into the intersphincteric space causes atrophy and weakness of the internal sphincter for a period of 2-20 days and gradual recovery within 2-4 months. This allows for general muscle relaxation and elimination of hypertonia. International literature reports a success rate of 92% in the first 2 months after application, a rate that drops to 79% at 12 months. It is considered superior to local application of ointments, but in case of failure, surgical treatment is indicated.
The surgical treatment consists of lateral internal sphincterotomy, which is the treatment of choice in case of failure of conservative treatment and shows the best success rates (>85%). The method consists of transection of some fibers of the internal sphincter, either blindly by entering the scalpel into the intersphincteric space, or openly through an incision in the intersphincteric groove. There is no rule regarding how much length of the internal sphincter the surgeon should cut. However, he must certainly be very careful and cut only as much as is necessary to eliminate the hypertonicity of the muscle, because otherwise there is a risk of incontinence (26-30%), a very serious complication about which the patient should be informed in detail by the treating physician preoperatively. However, with careful application of the method, lateral internal sphincterotomy is the most reliable solution for treating anal fissure.
