2. Small linear tear in anal mucosa
Majority occur in posterior midline
In women 10% found in anterior midline; less than 1% in males

3. Diagnosis
History alone usually renders dx. w/ symptoms of tearing, knife-like pain w/ or w/o bleeding, usually associated with forceful hard stool or diarrhea.
Pain starting w/ defecation lasts minutes to hours
Fear of symptoms often causes pt. to withhold stooling, exacerbating constipation, impaction and pain.

4. Examination
Gentle retraction of buttocks; pain is noted as fissure is exposed.
Edematous sentinel tag may be present
White fibers of internal sphincter may be seen in base of fissure or may be covered by thin epithelium which may hide the fissure
Digital exam may be attempted with very well lubricated finger pushing away from fissure.
Overhanging edges suggest chronicity

5. Etiology
Linear tear along the longitudinal axis of overlying epithelium covering internal sphincter.
Higher resting internal sphincter pressures are found in people with fissures
Shouten and associates have suggested decrease in blood flow as cause of fissures, accounting for the pain
Because increased resting anal pressure is associated with decreased mucosal blood flow- two may be related

6. Non operative treatment
Mainstay of tx. Is avoidance of straining at stool and use of sitz baths multiple times a day
Hydrocortisone creams and local anesthetic ointments such as lidocaine may help
Botulinum toxin injected into external anal sphincter on both sides of fissure
Topical nitroglycerin ointment ranging fr. 0.15% to 0.8% three to four times a day; concentration greater than 0.2% required to decrease MRAP by 25% but headaches increase accordingly

7. Diltiazem used in recent years as means of “chemical sphincterotomy”
Diltiazem used in recent years as means of “chemical sphincterotomy”. Best used as 2% topical preparation. Side effects generally less frequent vs. nitroglycerin
Anal dilatation incl. controlled dilation with rectosigmoid balloon under anorectal loval anesthesia

8. Operative techniques
Most sphincterotomies done as outpatient procedures with sedation and IV anesthesia.
Intersphincteric groove palpated laterally. Radial incision no more than 5mm is made