What is chemodenervation?
Chemodenervation uses a substance to block nerve signals that control muscles. The substance is botulinum toxin (BoNT). BoNT is a neurotoxin that stops nerves from releasing a chemical messenger—or neurotransmitter—that tells muscles to contract. This results in muscle relaxation. The effect is temporary, lasting up to three months before a repeat treatment is necessary.
Because the brand Botox was the first drug to use BoNT, people often refer to the procedure as Botox chemodenervation. However, there are currently four approved BoNT products:
- AbobotulinumtoxinA (Dysport)
- IncobotulinumtoxinA (Xeomin)
- OnobotulinumtoxinA (Botox)
- RimabotulinumtoxinB (Myobloc)
These drugs are not interchangeable. Each one has specific dosing and different approved indications.
Why is chemodenervation performed?
Doctors use chemodenervation to reduce muscle spasms, spasticity and dystonia. These are conditions in which muscles contract uncontrollably. Blocking nerve signals to these muscles allows them to relax. There are several applications for this including treating the following medical conditions:
- Axillary hyperhidrosis, which is excessive underarm sweating
- Blepharospasm, which is spasms or contracture of the eyelid
- Cervical dystonia, which is contraction of the neck muscles into a painful or uncomfortable twisting or turning position
- Chronic migraine, which is migraines on more than 15 days per month
- Limb spasticity, which occurs with conditions such as cerebral palsy
- Overactive bladder, which is a cause of incontinence
- Strabismus, which is an imbalance in the muscles controlling eye movements commonly called wall eye or cross eye
There are also several off-label uses for BoNT chemodenervation. These uses do not have FDA (Food and Drug Administration) approval. However, doctors generally accept these uses based on medical research. Off-label uses for BoNT include:
- Bruxism, which is excessive teeth grinding or jaw clenching
- Hidradenitis suppurativa, which is a rare skin condition with pimple-like bumps, cysts, boils and abscesses
- Rectal sphincter spasms
- Scoliosis, which is a sideways curvature of the spine
Talk with your doctor about all risks and benefits of the chemodenervation procedure to decide if it’s right for you.
Who performs chemodenervation?
There are many types of doctors that perform chemodenervation, depending on the condition they are treating. This includes:
- Dermatologists, or specialists in treating skin diseases and disorders
- Neurologists, or specialists in treating nerve and nervous system disorders
- Ophthalmologists, or specialists in treating diseases and conditions of the eye
- Otolaryngologists (ENTs), or specialists focusing on the ears, nose and throat
- Urologists, or specialists focusing on the urinary tract and male reproductive system
- Urogynecologists, or specialists focusing on female pelvic floor and bladder disorders
Look for doctors who are board-certified in their specialties. Then, ask about their experience with chemodenervation to treat your specific condition. Experience is important when choosing the specialist.
How is chemodenervation performed?
The chemodenervation procedure is an injection into the skin or muscles. In most cases, it’s an office procedure. The number of injections you need will depend on the condition your doctor is treating. It’s usually a quick procedure, but may take up to 20 minutes if you need multiple injections.
Most people do not need anesthesia because they experience only mild discomfort. However, some areas of the body are more sensitive than others. Doctors may recommend a topical anesthetic to numb certain areas, such as the armpit, palms of the hands, or soles of the feet.
What are the risks and potential complications of chemodenervation?
All procedures carry some level of risk of side effects and other complications. Your risk will depend on your medical history, why you need chemodenervation, and where your doctor injections BoNT.
Potential complications of chemodenervation
In experienced hands, chemodenervation is relatively safe. However, potential side effects include:
- Drooling or crooked smile
- Drooping eyelid or eyebrow
- Dry mouth or eyes
- Headache or neck pain
- Pain, swelling or bruising at the injection site
Reducing your risk of complications
You can reduce your risk of certain complications by:
- Informing your doctor if you are nursing or if there is any possibility of pregnancy
- Not rubbing or massaging the area for 24 hours afterwards
- Notifying your doctor immediately of any concerns or bothersome symptoms, even if they don’t seem related
- Taking your medications exactly as directed and not starting any new medicines without your doctor’s knowledge
- Telling all members of your care team if you have allergies, including food allergies
- Telling your doctor about all your medications, including blood thinners, allergy medicines, muscle relaxants, and sleep aids
How do I prepare for chemodenervation?
Chemodenervation doesn’t take much preparation, but there are things you need to let your doctor know. Prepare for chemodenervation by:
- Answering all questions about your medical history, allergies, and medications. This includes prescriptions, over-the-counter drugs, herbal treatments, and vitamins. It is a good idea to carry a current list of your medical conditions, medications, and allergies at all times.
- Letting your doctor know if you have had a BoNT injection in the last four months.
- Taking or stopping medications exactly as directed. This may include not taking aspirin, ibuprofen (Advil, Motrin), and blood thinners.
- Telling your doctor about any previous reactions to BoNT or if you have had surgery in the treatment area.
Questions to ask your doctor
Getting all your questions answered is important before having chemodenervation. Here are some questions you may want to ask:
- Why are you recommending chemodenervation for me?
- How will I receive the injections and how many injections do I need?
- How many chemodenervation procedures do you perform in a year in people like me?
- What side effects or complications do you see most often?
- What should I avoid during treatment?
- What are the possible long-term effects on my condition? How often will I need re-treatment?
- When and how should I contact you once I go home? Ask for numbers to call during and after regular hours.
What can I expect after chemodenervation?
It’s easier to plan and prepare for a successful recovery when you know what to expect.
How long will it take to recover?
You can resume regular activities right after chemodenervation. However, you should not rub or massage the area for 24 hours afterwards. Doing so may spread the neurotoxin to other areas and cause side effects.
Will I feel pain?
You will have mild discomfort during the procedure. The injection area may also be slightly sore afterwards, but you should not have pain.
When should I call my doctor?
If you have questions between follow-up appointments after chemodenervation, call your doctor’s office during normal business hours. Call doctor right away or seek immediate medical care if have:
- Loss of bladder control
- Problems breathing, swallowing or speaking
- Vision problems or changes in vision
- Weakness in your whole body
How might chemodenervation affect my everyday life?
Chemodenervation may help relieve symptoms related to muscle spasms and spasticity. If you have a positive response, the goal is to maintain it while avoiding side effects. Keeping a symptom diary can help you and your doctor decide if it’s working for you and how often you need re-treatment. Describe your symptoms in detail and record when they started and how long you had them. Share the diary with your doctor at follow-up appointments.