Botulinum neurotoxin injections are a common dystonia treatment, first used for blepharospasm 30 years ago. This is a highly specialized, ongoing therapy that must be customized to each patient. There are several factors that can influence the outcome for treatment, degree of benefit, and chance of side effects. It is also important to manage expectations before starting any new treatment protocol.
Mark S. LeDoux, MD, PhD, a clinician-scientist from Veracity Neuroscience in Memphis, TN, noted that the skill of the injecting physician is the most critical factor in clinical outcomes, even more than the amount of toxin injected. “Skilled injectors will often have a very good idea of how many units of toxin are necessary and what muscles to target,” Dr. LeDoux explained. “Injection skill is very important for treating writer’s cramp, blepharospasm and particularly laryngeal dystonia… There are many people who do injections but very few that are skillful enough to obtain optimal results on a consistent basis.” Dr. LeDoux believes that injections that are EMG guided will be most effective, especially for arm dystonia, leg dystonia, cervical dystonia, and laryngeal dystonia. EMG guidance is rarely required for blepharospasm. EMG guidance is a technique that uses electromyography signals to help healthcare providers accurately locate and inject needles into specific muscles for medical treatments. The system provides real-time audio and visual feedback, indicating when the needle has entered an active muscle, allowing for more precise delivery and potentially improving treatment outcomes by ensuring the toxin is delivered to the correct, affected muscle group. For patients who are new to receiving botulinum toxin treatments, here are a few things to keep in mind: • Getting to the Correct Dosage Takes Time: Doctors typically start with a smaller dosage of botulinum toxin and emphasize to the patient that an increased dose may be needed at future visits. Achieving the optimal dosage is a collaborative effort between the patient and physician, so patients should keep a record of the dosage amount where they started to notice any symptom improvements.
• Do Not Expect 100% Improvement: Even with injections performed by a skilled and highly experienced injector, results may still be suboptimal. Patients should expect an improvement in the severity of their dystonia when injected correctly, but it is unrealistic to expect the symptoms to disappear completely.
• Be Aware of Potential Side Effects: These may include neurovascular injury, infection, bruising, bleeding, excessive weakness, flu-like symptoms and other allergic responses, which are rare. Slight bruising is the most common potential side effect and usually resolves within five to ten days. Injections for cervical dystonia may cause some patients to develop head drop or dysphagia (difficulty swallowing).
• Injections Involve Multiple Sites: In general, there are two to three injection sites per muscle. For most patients with cervical dystonia at least three muscles will be injected. Other dystonia patients with leg or arm involvement may have more than five muscles injected, which means many patients will get 12 or more injections during one treatment session. Clinicians use either a 30-gauge or 27-gauge needle—the bigger the number the thinner the needle.
• Ask About Options to Lessen Needle Anxiety: Pediatric patients may benefit from a shot blocker (also called a shot pain reducer), which is a non-invasive device shaped like a small disc placed over the injection site that distracts patients from needle poke pain signals. Patients with significant anxiety may benefit from taking a benzodiazepine (such as alprazolam) one hour prior to injections.
• Educate yourself regarding cost coverage: Check your provincial healthcare and extended benefits to find out what the requirements are for cost coverage of botulinum toxin injections. Your doctor’s office or movement disorders clinic may be a good starting point to find more information on provincial coverage policies. Your extended benefits may require preapproval.
Additional training for physicians who administer botulinum toxin injections ultimately benefits dystonia patients. “Training is highly variable among different training programs,” Dr. LeDoux explained. “At many academic institutions, injections for blepharospasm may be performed by an ophthalmologist and injections for laryngeal dystonia may be performed by a laryngologist. There are very few neurologists who inject neurotoxins for all forms of dystonia.”
As a proactive patient, or the parent or caregiver of a dystonia patient, you have a right to fully understand all treatment options and any potential side effects associated with your choices. Knowing what to expect before treatment begins is an important part of taking control of your care.
Read the full article in our newsletter to learn more about what to expect from botulinum toxin treatment and how to advocate for your care.