Botulinum Neurotoxin as a Therapeutic Modality in Orthopaedic Surgery: More Than Twenty Years of Experience

Botulinum neurotoxins are among the most potent toxins found in nature, and are produced by Clostridium botulinum , an anaerobic, gram-positive, spore-forming rod-shaped bacterium1. There are seven known serotypes of botulinum neurotoxins (termed A, B, C1, D, E, F, G) that cleave soluble N-ethyl-maleimide-sensitive factor attachment receptor (SNARE) proteins, preventing effective release of neurotransmitters across specialized synaptic junctions. Blocking SNARE protein function within neuromuscular junctions produces flaccid paralysis, results in anhidrosis within sweat glands, and increases nutritional blood flow in vascular beds. On the basis of these findings, it was hypothesized that controlled injections of botulinum neurotoxins could be used to treat neuromuscular disorders. The benefits of botulinum neurotoxin injections in the treatment of various neurological disorders have captured the attention of physicians from multiple specialties and have contributed to the widespread use of botulinum neurotoxins in modern medicine2. Currently, only botulinum neurotoxin type-A (BoNT-A) and B (BoNT-B) serotypes are approved by the U.S. Food and Drug Administration. The mandated labeling includes the following therapeutic and anesthetic indications: (1) treatment of cervical dystonia in adults; (2) treatment of strabismus and blepharospasm associated with dystonia, including benign essential blepharospasm or seventh cranial nerve disorders in patients who are twelve years of age or older; (3) treatment of severe primary axillary hyperhidrosis; and (4) treatment of severe glabellar lines associated with corrugator and/or procerus muscle activity in patients who are sixty-five years of age or younger. This article outlines the role of botulinum toxins, particularly type A, as a therapeutic modality in musculoskeletal conditions on the basis of the peer-reviewed literature and the personal experience of the authors. Some of the information presented in this article describes off-label indications for drugs as defined by the Food and Drug Administration. The doses, side effects, techniques, and information reflect the …