Botulinum toxin A, is a toxin protein produced by bacteria called clostridium botulinum. When injected into a muscle, it will temporarily blocking neural signals for muscle contractions, causing the muscle fibers at the injection area to relax. Botulinum toxin A has been successfully used for the treatment of a variety of medical conditions involving unwanted muscle spasms such as strabismus and cervical dystonia. It is also commonly used for removing unwanted wrinkles in cosmetic care.
The internal anal sphincter that controls the anus is always under tension. If this tension (also called resting pressure) is too high, it causes rectal pain. The common diseases associated with anal sphincter spasms are anal fissure and functional anal rectal pain. Spasm can make an anal fissure worse or prevent an existing one from healing.
Botulinum toxin A has also been used to treat anal fissure for several years. Injecting Botulinum toxin A into muscle around the anus will temporarily relax the internal anal sphincter. This reduces the spasm and pain and allows the fissure to heal.
Most patients have at least some pain relief in their pain after treatment with Botulinum toxin A. The success rate for an anal fissure healing after the injection is 70 out of 100 treatments. Sometimes the injection might need to be repeated, especially in the patients with functional anorectal pain.
What Happens During the Procedure?
There is no special preparation needed before the injection procedure. You don’t need to do any preparation, but you are encouraged to have bowel movement and please do carry out your usual hygiene routine (shower or bath) before you come in.
Dr. Shu will perform the injection procedure in the exam room or procedure room, and it takes a few minutes to perform. You will be awake throughout the procedure.
You will be asked to lie on your left side on the exam table. The area around your anus will be cleaned with an alcohol spray. Dr. Shu will then give 6-8 injections of Botulinum toxin A into your sphincter muscle with a hair thin needle. This will be uncomfortable during the injection, but it is an extremely quick procedure.
After the Procedure
You can drive home or return to work afterwards. Very occasionally, the patient develops vasovagal reaction (fainting) to the procedure, the you lie on the table for a few minutes to recover.
The Botulinum toxin A will start to work in a few days. The effects of Botulinum toxin A peaks in 1-2 weeks and usually lasts 3-6 months. During this time, anal fissures are allowed to heal.
Most people do not have any side effects. The potential side effects of botulinum injections may include the inability to control the passage of gas (gas incontinence), pain from the injections, bleeding, infection at the injection site, and rarely, fecal incontinence (we don’t have any case of fecal incontinence). If symptoms of incontinence occur following Botox® injection, they typically disappear completely after several months.
It is important to make sure that you continue to keep your stool soft following the treatment, to avoid straining. Continue anal care measures including Sitz bath, fibre in your diet, and drinking enough water.