Treatment Of Facial Dystonias Research Articles

Outcomes of a regional variant of botulinum toxin type A in the treatment of essential blepharospasm and hemifacial spasms: A retrospective study.

Purpose:The aim of this study was to report the outcomes of a regional variant of botulinum toxin type A (BtA) in essential blepharospasm and hemifacial spasm.Methods:The medical records of all patients with facial dystonias, who received at least one dose of BtA between May 2016 and April 2017 were retrospectively evaluated. The pre- and post-injection severity of symptoms, graded using the Jankovic rating system for essential blepharospasm and the Samsung Medical Center grading system for hemifacial spasm, the complications after each sitting, and the mean symptom-free interval were recorded. A correlation analysis was done to identify factors associated with longer symptom-free intervals. A P value < 0.05 was considered statistically significant.Results:The mean age at presentation was 56.62 ± 10.56 years. The mean duration of follow-up was 1.86 ± 2.06 years. The modal disease severity reduced from 5 to 0 in essential blepharospasm and from 2 to 0 in hemifacial spasm a week after injection of botulinum toxin. The mean symptom-free intervals with doses of 20, 22.5, 25, 30, and 50 units were 102.1 ± 44.7, 132.4 ± 35.3, 147.2 ± 61.6, 124.4 ± 55.1, and 142.4 ± 59.7 days, respectively. The commonest complication was lagophthalmos (26.3%; n = 20). Injections for primary dystonias were associated with longer disease-free intervals than those for secondary dystonias (P = 0.02). In nine sittings, the dose was increased for increased severity or presumed resistance, which resulted in a significant increase in the symptom-free interval (P = 0.004) without an increased incidence of complications (P = 0.48).Conclusion:BtA is safe and effective in the treatment of facial dystonias. The drug is more efficacious for primary facial dystonias.

A Comparison of Facial Muscle Squeezing versus Non-facial Muscle Squeezing on the Efficacy of BotulinumToxin-A Injections for the Treatment of Facial Dystonia

Background:This study was performed to address whether voluntary muscle squeezing post botulinum toxin-A treatment with increased neuronal activity translates into noticeable patient benefit in practice.Methods: This was a prospective, consecutive, double crossover interventional study. Participants were receiving regular (3 monthly) botulinum toxin-A treatment for aberrant facial nerve regeneration (AFNR), benign essential blepharospasm (BEB) or hemifacial spasm (HFS). Twenty-six participants were recruited and these were randomised into two groups (A and B). Group A performed a program of intensive facial exercises for 5 minutes after their first and third treatment whereas after their second treatment, they were asked to rest in a seated position for 5 minutes, and instructed not to talk or perform any voluntary movements of their face. Conversely group B were only asked to perform squeezing exercises after their second treatment. Outcomes were evaluated objectively using video-recordings and subjectively by questionnaire and telephone interview of participants.Results: Video-recording data was complete for 21 participants. There was a mean 40% reduction in the frequency of facial muscle spasms and a 33% lower severity score (video-recordings graded by 1 masked investigator) where intensive facial exercises were performed post-treatment. These findings did not reach statistical significance (Mann- Whitney two-tailed test; p = 0.367).Conclusion: Although statistical significance was not achievable, this study suggested a possible trend towards an increased efficacy of botulinum toxin-A, with facial muscle squeezing post BTX treatment. Future studies with a larger number and a better defined subset of subjects may lead to statistical significance.

Noncosmetic periocular therapeutic applications of botulinum toxin

Botulinum toxin blocks acetylcholine release at the neuromuscular junction. The drug which was initially found to be useful in the treatment of strabismus has been extremely effective in the treatment of variety of conditions, both cosmetic and noncosmetic. Some of the noncosmetic uses of botulinum toxin applications include treatment of spastic facial dystonias, temporary treatment of idiopathic or thyroid dysfunction-induced upper eyelid retraction, suppression of undesired hyperlacrimation, induction of temporary ptosis by chemodenervation in facial paralysis, and correction of lower eyelid spastic entropion. Additional periocular uses include control of synchronic eyelid and extraocular muscle movements after aberrant regeneration of cranial nerve palsies. Cosmetic effects of botulinum toxin were discovered accidentally during treatments of facial dystonias. Some of the emerging nonperiocular application for the drug includes treatment of hyperhidrosis, migraine, tension-type headaches, and paralytic spasticity. Some of the undesired side effects of periocular applications of botulinum toxin inlcude ecchymosis, rash, hematoma, headache, flu-like symptoms, nausea, dizziness, loss of facial expression, lower eyelid laxity, dermatochalasis, ectropion, epiphora, eyebrow and eyelid ptosis, lagophthalmos, keratitis sicca, and diplopia.

Absence of Muscle Spindles in Human Facial Muscles

Background: It has not previously been clarified if human facial muscles possess either typical muscle spindles, spindle-like structures or no spindles at all. Methods: Six patients from the Institute of Anatomy were used to investigate the Mm. orbiculares oculi and orbiculares oris. The age ranged from 53 to 91 years; three were males, three females. The specimens were imbedded in paraffin and examined in serial sections. Muscles were prepared for histological (H&E and Elastica van Gieson) and immunohistochemical (protein S-100, neurofilaments, and PGP 9.5) stainings. Results: All biopsies showed skeletal muscle fibers with some discrete alterations according to age. In some regions there were many small peripheral nerve fibers in close vicinity to muscle; but spindle-like structures with intrafusal fibers could not be detected. There were no signs of a sensorimotor double innervation of striated muscle fibers. Discussion: Previous investigators came to conflicting results regarding the absence or presence of muscle spindles in human facial muscles. However, in previous studies serial sections and immunohistochemical investigations had not been performed. Our observation of lacking muscle spindles in the facial muscles has several clinical and neurophysiological implications: (1) Pathological central muscle spindle afferent processing is assumed in the pathophysiology of dystonia. Although botulinum toxin leads to a denervation of muscle spindles its effect in the treatment of facial dystonias cannot be related to that. (2) A central facial paresis shows no signs of spasticity even in the chronic stage. Spasticity results in part from abnormal spinal processing of proprioceptive input mediated by Ia afferents. Thus, the absence of muscle spindles in the facial muscles may explain the lack of spasticity in these muscles. (3) In contrast to limb muscles, electrical facial and trigeminal nerve stimulations do not evoke silent periods and facial muscles show no facilitation of magnetic evoked potentials by vibration stimuli. Both phenomena are mediated by Ia afferents and their absence can be explained by the lack of muscle spindles.

Failures in Clinical Practice and a Biomechanical System for the Study of Toxin-Induced Paralysis

Botulinum A toxin injection has great utility in the treatment of essential blepharospasm and other facial spasm disorders. Several investigators have noted the failure of botulinum toxin injections to relieve lid spasm in occasional patients and a decrease in effectiveness or duration of effect following multiple injections in other patients. We reviewed the charts of 30 consecutive patients presenting for the evaluation or treatment of facial dystonia. Of 20 patients who had received multiple injections of botulinum toxin, 10 patients were felt to be treatment failures. A new biomechanical system was developed to investigate the duration and degree of paralysis induced in the gastrocnemius muscle of the rat. Animals were treated with four sequential injections at 6-week intervals to the same muscle, resulting in muscle atrophy and an increase in the duration and degree of muscle paralysis, contrary to clinical findings in humans. The review of patient data confirms that, for many patients, repeated injection of botulinum toxin results in a decrease in duration and degree of effect despite an increased toxin dose. An opposite effect was noted in our experimental model because of progressive muscle atrophy.

Long-term Results and Complications of Botulinum A Toxin in the Treatment of Blepharospasm

The authors review their long-term results and complications with the use of botulinum A toxin in the treatment of facial dystonias. Two hundred thirty-two patients in three diagnostic groups—essential blepharospasm, hemifacial spasm, and Meige's syndrome—were treated with botulinum A toxin. A total of 1044 treatments were given over a 4-year period. A reduction in orbicularis spasm intensity was noted in 1012 (96.9%) treatments (mean duration, 13.3 weeks). There was no clear relationship between toxin dose and the amount of spasm reduction or duration of response, and average duration of beneficial effect remained constant from the first through the twelfth injections. Complications occurred in 236 (22.6%) treatments. In most cases, these were local and transient. Symptomatic dry eye was the most common side effect, noted in 7.5% of cases. Ptosis was reported in 7.3% of treatments and photophobia in 2.5%. Diplopia involving the inferior oblique or lateral rectus muscles was seen in less than 1 % of cases. There were no differences in degree of response or in complications among the three diagnostic groups, although there was a slight difference in duration of effect. Patients who had undergone previous eyelid surgery for blepharospasm did not respond differently from those without prior surgery.