Bacteria Clostridium botulinum produces a neurotoxin known as Botulinum toxin. The toxin acts in the neuromuscular junction and disrupts the release of vesicles containing the neurotransmitter Acetyl Choline which is responsible for muscle contraction. This causes paralysis of the muscle. There are seven main types of botulinum toxin of which types A and B can cause disease in humans. This is available commercially as Botox. One would wonder how a toxin that causes paralysis can be used as a medicine. Well, there are several neurological conditions where there is excessive muscle contraction. Conditions like hemi-facial spasm, spasticity, Dystonia, overactive bladder, achalasia, cosmetic skin conditions. Visit Manipal, Neuro Hospital in Mangalore to know more about these conditions.
Oromandibular dystonia is a type of dystonia characterized by abnormal contractions of jaw muscles, mouth, and tongue. Jaw dystonia is characterized by abnormal contractions of lateral pterygoids and digastric. These muscles are involved in the opening of the jaw. Patients with jaw opening dystonia are unable to close their jaw as it is kept open by excessively contracting lateral pterygoid muscles.
Botox can be given into the lateral pterygoid muscles by intraoral approach (inside the mouth) or extraoral (from outside the mouth). The external approach is the most commonly used. Injecting Botox by using an extraoral approach can be done by using EMG. The risk associated with the blind injection is injuring the maxillary artery which is there closely, therefore, leading to bleeding. Also injecting into an area apart from the lateral pterygoid muscle may not produce the desired benefit.
We report a patient with Jaw opening dystonia. He was having difficulty in the closing jaw which caused difficulties in speaking, chewing food. He was initially given medicines to improve dystonia with which there was minimal improvement. Hence he was offered a Botox injection. We used a technique called CT-guided injection of Botox. The muscle was identified by CT, the needle was inserted into the lateral pterygoids by extraoral approach, depth of the muscle measured again by CT and then Botox was injected. The advantage of this technique is that injection can be given accurately into the desired muscles improving the outcome. Also, the side effects associated with blind injections like injuring the maxillary artery can be avoided. This patient had a remarkable improvement after the procedure. To know more about such conditions, consult with our Neurologist in Mangalore.
Consultant - Neurology
Manipal Hospital, Mangalore
