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Botulinum toxin treatment of hemifacial spasm and blepharospasm : objective response evaluation.
Correspondence Address:
Twenty seven patients with hemifacial spasm (HFS) and sixteen patients with blepharospasm (BS) having mean Jankovic disability rating scale score of 2.56+0.58 SD and 2.81+0.54 SD, respectively, were treated with botulinum toxin A (BTX-A) injections. The total number of injection sessions were ninety one with relief response in 98.91%. The mean improvement in function scale score was 3.78+0.64 SD and 3.29+1.07 SD respectively, in HFS and BS groups. The clinical benefit induced by botulinum toxin lasted for a mean of 4.46+3.11 SD (range 2 to 13) months in HFS group and 2.66+1.37 SD (range 1 to 6) months, in BS groups. Transient ptosis was seen in 4.39% of total ninety one injection sessions. These findings show that local botulinum toxin treatment provides effective, safe and long lasting relief of spasms.
Hemifacial spasm (HFS) and blepharospasm (BS) are two chronic distressing and embarrassing movement disorders of the face. HFS is a disorder characterised by episodic and intermittent twitching, tonic spasm and synkinesis of the muscles of one side of the face innervated by the facial nerve. In contrast, BS is a form of focal dystonia characterised by involuntary spasmodic closure of eyelid on one or both sides. Dystonia is difficult to treat medically. The injection of botulinum toxin (BTX) has now become an accepted treatment for many forms of hyperkinetic disorders including BS and HFS.[1],[2],[3],[4] In India, there are a few reports concerning local experience of botulinum toxin treatment in HFS and BS.[5],[6] The idea of the present study is to share the Indian experience and to quantify the treatment effect of local botulinum toxin injections in HFS and BS.
Forty three consecutive patients of HFS (27) and BS (16), were selected from the out-patient department of Neurology service of the Postgraduate Institute of Medical Education and Research, Chandigarh to undergo botulinum toxin therapy, after obtaining their informed consent. All patients underwent full clinical evaluation. None of the patients had been treated with botulinum toxin before. All patients refrained from taking other drugs for atleast four weeks before the study. The severity of spasm was graded clinically from grade 0 to grade 4 according to Jankovic disability rating scale[7] : 0 - normal, 1 - slight disability, no functional impairment, 2 - moderate disability, no functional impairment, 3 - moderate disability, functional impairment and 4 - incapacitated. Two different preparations of botulinum toxin type A (Dysport, Speywood Pharmaceuticals Ltd., UK and Botox, Allergan, Inc, Irvine, CA) were used as per availability of the injection in the market. In practice, experience has shown that one unit of Botox is equivalent to 4 units of Dysport.[8] The manufacturer's instructions were carefully followed. The toxin was used within 4 hours of its reconstitution. A vial of 500 units freeze dried Dysport toxin was reconstituted with 2.5 ml of preservative free 0.9% saline solution to yield toxin in a concentration of 20 units per 0.1 ml. Similarly, a vial of 100 units freeze dried Botox toxin was reconstituted with 4 ml of preservative free 0.9% saline solution to yield toxin in a concentration of 2.5 units per 0.1 ml. The toxin was injected subcutaneously into the selected sites using a 1 ml tuberculine syringe with a 27-29 gauge needle. The dose was calculated on the basis of the severity and location of patient's spasm. In blepharospasm, three to four periocular injections at the medial and lateral aspects of upper and lower eyelids near orbital rim were injected with due technical considerations.[7] In hemifacial spasm four periocular sites as above were selected. The cheek was injected in cases having severe degree of retraction of angle of mouth [Figure 1]. The dose of botulinum toxin was calculated according to the prevalent reports in literature and modified according to the severity of clinical status.[2],[7] The dystonia was reassessed before each injection. Patients were evaluated at two to four weeks interval after each injection. They were given a diary to note the onset of clinical response, peak effect,duration of clinical improvement and complications on follow up assessment. Telephonic contact with the patients was encouraged for follow up assessment. Magnitude of subjective response considering improvement in function scale (0 to 4) was assessed on follow up[7] : 0 - no effect, 1 - mild effect but no functional improvement, 2 - moderate improvement but no change in functional disability, 3 - moderate change in both severity and function, 4 - marked improvement in severity and function. Results were expressed as mean + SD.
A total of 43 patients were studied. 27 cases with HFS had mean Jankovic disability rating scale score of 2.56+0.58 SD (range 2 to 4) and 16 cases with BS had the mean disability score of 2.81+0.54 SD (range 2 to 4). The mean age of patients was 47.78+9.92 years (range 30-67) and 51.06+10.48 years (range 30-71) years respectively, in HFS and BS when botulinum toxin treatment was started. The mean age at onset of spasm in HFS and BS was 43.09+9.96 SD years (range 27-62) and 46.98+11.59 SD years (range 27-67) respectively. The mean duration of spasm before botulinum toxin treatment was 4.67+3.7 SD years (range 3 months to 17 years) in HFS and 3.73+3.68 years (range 3 months to 15 years) in BS. There were 68.7% males and 31.3% females with BS and 29.6% males and 70.4% females with HFS. BS was bilateral in 75%. HFS was present on the right side in 48.15% and on the left side in 51.85% of patients. Various exacerbating factors for both movement disorders were reported by the patients [Figure 2]. In order of decreasing frequency these were stress (48.84%), sunlight (48.84%), talking (34.88%), watching television (30.23%), reading (20.93%), walking (18.6%), diurnal variation (13.95%), eating (9.3%) and others (9.3%). A total of 91 botulinum toxin A injections were given in the present study. 45 sessions were in patients with HFS and 46 sessions in patients with BS. Mean injections per patient were 1.67+0.96 SD (range 1-4) in HFS and 2.87+2.09 SD (range 1-7) in BS. Dysport injection was used on 32 occasions in HFS and 33 occasions in BS. During the remaining session Botox was used. The mean dose injected per patient per session in HFS was 74.37+29.78 (range 50-180) units of Dysport and 12.73+1.82 (range 10-18) units of Botox, yielding cumulative total dose of 2380 units of Dysport and 165.5 units Botox, respectively. Dysport was used in 71.11% patients and in 28.89% cases Botox was used. The mean dose injected per patient in one session in BS was 118.03+56.11 SD (range 50-260) units of Dysport and 26.85+9.68 (range 12-40) units of Botox, yielding cumulative total dose of 3895 units Dysport and 349 units Botox. Dysport was injected in 71.74% patients and in the remaining cases Botox was used. Botulinum toxin injections were well tolerated. Side effect of blepharoptosis was observed in 4.39% of total injection sessions; which however, cleared after a few days. No systemic or other effects were noted. All patients except one with BS experienced relief (98.91% of all treatment sessions). Out of all 91 treatment sessions, the mean improvement in function scale score was 3.78+0.64 SD in HFS and 3.29+1.07 SD in BS. The onset of beneficial effect after botulinum injection ranged from 1 to 15 days (mean 3.31+3.52 SD) in BS and 1 to 9 days (mean 3.07+1.66 SD) in HFS. The effect peaked at 10+5.24 (range 2-24) days in BS and 11.63+7.07 (range 7-30) days in HFS. Benefit from each session in HFS and BS, respectively, lasted a mean of 4.46+3.11 SD (range 2-13) months and 2.66+1.37 (range 1-6) months [Table I]. The relief response was not influenced by age, sex, age at onset, duration of symptoms before treatment and side of involvement.
Botulinum toxin (BTX) is a potent neuroparalyzing agent.[7],[9] The bacterium Clostridium botulinum produces seven serologically distinct toxins designated as A, B, C, D, E, F and G. Since the introduction of BTX into therapeutics in 1978 for strabismus,[10] botulinum toxin type A, one of the most lethal biologic toxins, has been found to be of therapeutic value in the treatment of a variety of neurological disorders.[7],[11] BTX exerts its effect by preventing the release of acetylcholine from presynaptic vesicles. The active form of the toxin produces denervation through a three-step process : 1) toxin binding to nerves, 2) internalisation and 3) inhibition of neurotransmitter release. The present results confirm that patients with HFS and BS can benefit from local injections of botulinum toxin. As in previous series,[12],[13] most of the cases with BS reported subjective improvement with botulinum toxin injection in the present series. The onset of beneficial effect, peak effect and duration of clinical benefit in response to BTX-A are comparable with those observed, by various investigations who used botulinum toxin to treat dystonias, muscle cramps, spasticity and rigidity.[11],[14],[15],[16] The study of Jankovic et al[1] disclosed that patients with HFS had longer-lasting improvement than those with focal dystonia. The present study also confirms this as evidenced by duration of improvement in HFS as mean 4.46+3.11 months compared to duration of improvement in BS mean 2.66+1.37 months. The longer duration of improvement may be due to the subclinical denervation in patients with HFS.[17] The relief response was not influenced by age, sex, age of onset of dystonia, duration of symptoms before treatment and side of involvement. Although Karp et al[18] showed that females had a greater relief and longer duration of benefit than males treated with botulinum toxin for hand dystonia, the present study did not observe sex difference in the outcome of botulinum toxin therapy in HFS and BS.[18] A large number of exacerbating factors like stress, sunlight, talking, watching TV etc. were reported by the patients in the present series. Similar situational exacerbating factors have been noted by other authors.[19] Despite the considerable variations in dose, results reported with Dysport and Botox injection in the present study were similar to previous reports.[20],[21] The observed incidence of blepharoptosis as a complication of BTX-A therapy in previous series was 12.3% (range 0-52.3%).[12] In the present study, it was noticed only in 4.89% of all treatment sessions. The ptosis may be due to toxin diffusion into the muscular portion of the levator palpebrae superioris muscle causing chemodenervation which was cleared in a few days. In comparison to the use of BTX-A for major dystonias eg. cervical dystonia and its use for spasticity management as is being promoted in the west, its use for HFS and BS would be more appropriate in our set up considering that a much smaller dose of BTX-A is required (hence less cost) for management of these disorders. We strongly recommend its use as a first line management drug for HFS and BS. Its use by neurophysicians trained in movement disorder management cannot be over emphasized considering the toxicity of BTX-A. Our experience fortifies the fact that local botulinum toxin treatment provides effective, safe and long lasting relief of spasms and botulinum toxin treatment holds promise for HFS and BS.
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