Botox Injections
Botulinum toxin has been used for medical purposes in humans since the early 1980’s when it was first used to treat strabismus, a condition commonly seen in children that involves “crossing of the eyes” secondary to failure of the extraocular muscles to work together synchronously. Since then, botulinum toxins have gained worldwide recognition for their beneficial effects in a myriad of medical conditions. However, growing popularity in Hollywood and cosmetic medicine, given the toxin’s ability to soften wrinkles, has obscured some of the major medical advances that have been realized in recent years.
The toxin is produced by a bacteria, Clostridium Botulinum [Figure 1]. The bacteria produces 7 similar, yet serologically distinct neurotoxins (Labeled A, B, C1, C2, D, E, F, G). Types A and B are the only serotypes currently used for medicinal purposes, and types C and D only cause symptoms in animals. Different production and purification methods are utilized to make the toxin safe for medical use. Commercially available type A neurotoxin (e.g. BOTOX) is the most widely available serotype.
Figure 1: Clostridium Botulinum
Botulinum toxins act directly on muscle tissue by blocking the release of acetylcholine at the presynaptic neuromuscular junction, causing relaxation of muscle [Figure 2]. Without acetylcholine muscle fibers can’t contract. It is also thought that botulinum toxins block the release of certain inflammatory mediators in sensory pain fibers.
Figure 2
Today, there are numerous medical conditions that are seen in a spine and pain management setting that are being treated with botulinum toxins. Some examples include painful conditions of the head and neck (e.g. cervical dystonia, chronic headaches, chronic myofascial pain), thoracic and lumbar spine (e.g. myofasical pain and postlaminectomy pain syndrome) and extremities (e.g. spasticity, focal dystonias, piriformis syndrome and chronic neurogenic pain).
Botulinum toxin injections have been shown to be safe and well tolerated in many clinical settings. Side effects depend on the part of the body injected, dose and dilution used, the condition being treated and coexisting illnesses. If you are being considered for treatment with botulinum toxins, your physician will discuss the potential side effects with you. In a pain management setting, these injections are usually considered after more traditional measures have failed. The exception to this is in the treatment of cervical dystonia, in which botulinum toxin injections are considered a first line treatment.
