الفهرس 
Anatomy of Pelvic FloorOnly 14 pages are availabe for public view
 |  | from | 144 |  |  |
| | | from | 144 | | |
Abstract
Anal fissure is an elongated ulcer in the long axis of lower anal canal. Simple anal fissures occur almost exclusively in the midline, both anteriorly and posteriorly.
Acute anal fissure is a radial split in the anoderm extending from the anal verge for a variable distance proximally towards the anal canal. These fissures are seen associated with constipation, child birth, and severe diarrhea.
Chronic anal fissures are those which fail to heal and form a linear, indurated chronic ulcer.
The pathogenesis of the anal fissure is poorly understood, theories include; the passage of hard fecal mass leading to trauma of the anoderm of the lower anal canal. Another theory; hypertonicity of internal anal sphincter which lead to raised resting anal pressure which lead to raised anal resting anal pressure. Local ischemia play an important role, as there is relative hypoperfusion area at the posterior commisure of the anal canal in most patients with anal fissure.
The object of all treatment for this condition is to obtain complete relaxation of the internal anal sphincter, provided the complications are dealt with, the fissure will slowly heal as soon as all spasm has disappeared.
Acute anal fissures usually heal spontaneously or with conservative treatment within 6 weeks.
Chronic anal fissures have traditionally treated by surgical division of the internal anal sphincter, which reduce the anal hypertonia leading to improvement of the anodermal blood flow and heal anal fissure.
The lateral internal sphincterotomy was the standard operation in surgical intervention for the treatment of anal fissure, as it leads to rapid symptom relief. Incontinence can follow the procedure, which is a problem, for this reason an alternative treatment for anal fissure was sought.
This lead to the search for alternative non surgical treatment by the use of various pharmacological agents, that is known to lower resting anal pressure, and thus healing fissure without threatening anal continence. This is known as chemical sphincterotomy.
Nitric oxide (NO) is an inhibitory neuro transmitter, glyceryl trinitrate (GTN) and isosorbide dinitrate (ISDN) both are NO donors and can be applied locally to the anus and have been shown to lower internal anal sphincter pressure and heal chronic anal fissures in majority of patients.
A ca++ dependant mechanism is required for internal smooth muscle tone, so ca channel blockers cause relaxation of the GIT smooth muscle tone. Nifedipine and deltiazem are ca channel blockers that are used in this respect.
Botulinum toxin works by inhibition the acetyl choline release into the neuromuscular junction, thus reducing anal sphincter pressure and allowing greater blood flow to the perianal region and thereby promotes healing of the fissure.