Prospective Assessment of Peri-Oral Weakness Following Peri-Orbital Botulinin Toxin for Blepharospasm

"In our experience performing peri-orbital injections of botulinin toxin for benign essential blepharospasm (BEB) we have encountered three patients who have experienced persistent ptosis of the upper lip. Notably, these patients have not had injection of any of the apparently weakened peri-oral musculature.. In addition, this appears to be possibly chronic, as the individuals affected have continued to experience lip ptosis even as their blepharospasm symptoms return and they require additional injection, typically at 3-4 month intervals. There are reports of botulinin toxin unmasking previously subclinical myasthenia, although these patients we are describing have never developed any other symptoms of myasthenia. There is a single case series identified in our literature review of three patients who experienced transient lip ptosis following injections done for cosmetic treatment of "crow's feet." (Mararasso 2001). To our knowledge, a prospective study to assess for the incidence of this particular side effect has not been undertaken."