An anal fissure is a painful tear in the tissue lining the inside of the anal canal (just inside the anal opening), which then fails to heal due to spasm in the muscle ring around the anus.
The main symptom is severe pain during or after a bowel movement, which can last for several hours. People often describe the discomfort as ‘like passing a piece of broken glass’. Sufferers may delay going to the toilet because of the pain and become constipated. Passage of the resulting hard faeces then causes further tearing, and worsens the condition.
One treatment for anal fissures is to use a special nitrate ointment to relax the sphincter muscle, reducing spasm and easing the pain, and allowing the fissure to heal. Many people however may find applying the cream inconvenient or embarrassing, and can get headaches, sometimes so severe that it that prevents them from using it.
An alternative is a Botulinum toxin (BOTOX) injection into the anal sphincter muscle instead, which relaxes the muscle sufficiently to prevent spasm and pain, allowing the fissure to heal. The procedure is performed under a brief general anaesthetic (with you asleep) as a day case; meaning that you will usually be able to go home within an hour or two of having the procedure performed, although occasionally the procedure can be performed without an anaesthetic.
The procedure is safe and has very few side effects; in fact the main advantage of BOTOX injection is the avoidance of lateral sphincterotomy surgery (permanent division of part of the anal sphincter muscle) a procedure that has a minor risk of incontinence.