Long-term efficacy of botulinum a toxin for blepharospasm and hemifacial spasm

Botulinum toxin treatment for hemifacial spasm: harmonising neurological and aesthetic outcomes

Hemifacial spasm (HFS) represents a challenging cranial movement disorder primarily affecting the facial nerve innervated muscles, with significant prevalence among Asians. Botulinum toxin type A (BoNT/A) injections, established as a primary therapeutic intervention since FDA approval, offer considerable effectiveness in alleviating spasms, albeit accompanied by challenges such as temporary effects and potential adverse events including facial asymmetry. This comprehensive review underscores the crucial need for harmonising neurological benefits and aesthetic outcomes in HFS management. The discussion delves into the interplay between facial aesthetics and neurological objectives in BoNT/A injections, emphasising precise techniques, dosages, and site considerations. Distinct aspects in neurological and aesthetic domains are also examined, including detailing the targeted muscles and injection methodologies for optimal therapeutic and aesthetic results. Importantly, evidence regarding various BoNT/A formulations, recommendations, and reconstitution guidelines in both neurology and aesthetics contexts are provided, along with a schematic approach outlining the stepwise process for BoNT/A injection in HFS treatment, addressing critical areas such as orbicularis oculi muscle sites, eyebrow correction strategies, mid- and lower-face considerations, contralateral injection sites, and post-injection follow-up and complication management. By highlighting the culmination of neurological efficacy and facial esthetics in BoNT/A treatment for HFS patients, this review proposes a holistic paradigm to achieve balanced symptomatic relief and natural aesthetic expression, ultimately enhancing quality of life for individuals grappling with HFS.

Patient Characteristics and Real-World Use of Botulinum Toxins for the Treatment of Cervical Dystonia, Blepharospasm, and Hemifacial Spasm

Movement disorders such as cervical dystonia, blepharospasm, and hemifacial spasm negatively impact the quality of life of people living with these conditions. Botulinum toxin (BoNT) injections are commonly used to treat these disorders. We sought to describe patient characteristics, BoNT utilization, and potential adverse events (AEs) among patients with cervical dystonia, blepharospasm, and hemifacial spasm using Optum's de-identified Clinformatics® Data Mart Database. Patients were required to have a diagnosis of the specific condition plus evidence of treatment with BoNT between 8/1/2010 and 5/31/2022. Cervical dystonia patients were commonly females (76%) and aged 45 and older (78%); both blepharospasm and hemifacial spasm patients were commonly females (both 69%) and aged 65 and older (61% and 56%, respectively). Anticholinergics were commonly used (65-82% across cohorts), as were peripheral muscle relaxants for cervical dystonia patients specifically (31%). The median number of injections per year was 2 with the median weeks between injections being between 13 and 15. Of the AEs evaluated, dyspnea was identified frequently across all the cohorts (14-20%). The findings were similar for different BoNT formulations. More research is needed to thoroughly describe BoNT utilization, such as the doses injected, and to optimize treatment for patients with these conditions.

Effects of the periocular botulinum toxin on the ocular surface and anterior chamber: a prospective study in patients with hemifacial spasm and blepharospasm

PURPOSE

To analyze using Pentacam®, the corneal and anterior chamber changes following periocular botulinum toxin injection in patients with facial dystonia.

METHODS

Prospective study that included patients with facial dystonia that were going to receive a periocular botulinum toxin injection for the first time or six months or more after the previous injection. A Pentacam® examination was carried out in all patients before and 4 weeks after the injection.

RESULTS

Thirty-one eyes were included. Twenty-two had a diagnosis of blepharospasm and nine of hemifacial spasm. Analysis of corneal and anterior chamber parameters revealed a significant decrease in iridocorneal angle after botulinum toxin injection (from 35 ± 10º to 33.8 ± 9.7º, p = 0.022). No other corneal or anterior chamber parameters changed significantly after the injection.

CONCLUSIONS

Periocular botulinum toxin injection causes narrowing of the iridocorneal angle.

Botulinum Toxin for the Treatment of Hemifacial Spasm: An Update on Clinical Studies

Hemifacial spasm (HFS) is a movement disorder characterized by involuntary contractions of the facial muscles innervated by the seventh cranial nerve. Generally, it is associated with a poor quality of life due to social embarrassment and can lead to functional blindness. Moreover, it is a chronic condition, and spontaneous recovery is rare. Intramuscular injections of Botulinum Toxin (BoNT) are routinely used as HFS treatment.

METHODS

We reviewed published articles between 1991 and 2021 regarding the effectiveness and safety of BoNT in HFS as well as any reported differences among BoNT formulations.

RESULTS

The efficacy of BoNT for HFS treatment ranged from 73% to 98.4%. The mean duration of the effect was around 12 weeks. Effectiveness did not decrease over time. Adverse effects were usually mild and transient. The efficacy and tolerability of the different preparations appeared to be similar. Among the studies, dosage, injected muscles, intervals of treatment, and rating scales were variable, thus leading to challenges in comparing the results.

CONCLUSIONS

BoNT was the treatment of choice for HFS due to its efficacy and safety profile. Further studies are needed to investigate the factors that influence the outcome, including the optimal timing of treatment, injection techniques, dosage, and the best selection criteria for formulations.

Hemifacial spasm through the last three decades: From etiology to efficacy and safety of long-term botulinum toxin treatment

BACKGROUND

Hemifacial spasm (HFS) is an uncommon movement disorder characterized by involuntary contractions of muscles innervated by the facial nerve. The aim of this study is to analyze the etiology of HFS as well as the efficacy and safety of long-term botulinum toxin type A (BTX-A) treatment.

METHODS

Retrospective study including 125 patients with HFS treated with BTX-A from 1993 to 2019. Demographic and etiological variables as well as doses, number of sessions of BTX-A, infiltrated muscles, therapeutic response according to Patient Global Impression of Change Scale (PGIC-S), side effects and adjuvant treatments were analyzed. In addition, these variables were compared according to the etiology (idiopathic versus secondary).

RESULTS

92 patients (73.6%) were women and the mean age at diagnosis was 58.63 years (SD 15.4). The etiology was idiopathic in 79 patients (63.2%), 17.6% were secondary to Bell's palsy, 14.4% to vascular compression and 2.4% to tumors. A higher total dose per session was observed in the secondary group. PGIC-S showed a good response in 96% of cases. 16 patients (12.8%) required pharmacological concomitant treatment. 59 patients (47.2%) developed side effects. Transient eyelid ptosis and facial weakness were the most common.

CONCLUSIONS

The structural origin of a significant number of cases of HFS makes essential to complete an etiological diagnosis in all patients. In addition, the existence of a secondary cause could be associated with greater doses of BTX-A to achieve a good response. Regardless the etiology, long-term treatment with BTX-A in HFS is safe and effective.

Personality traits associated with blepharospasm: A comparison with healthy subjects, patients with facial hemispasm and patients with hyperhidrosis

The aim of this study is to explore the existence of specific personality traits related to patients with blepharospasm (BSP), treated with injections of botulinum neurotoxin (BTX). Sixteen patients with BSP, 22 with facial hemispasm (HFS), 20 with essential hyperhidrosis (EH) and 20 healthy controls (HCs) completed the Temperament and Character Inventory-Revised to explore personality traits based on Cloninger's Psychobiological Model. The results revealed that the four groups differed on the Harm Avoidance (HA) scale and fear of uncertainty subscale, as well as on Persistence (PS). On HA, BSP group did not differ from HCs, but had higher scores than HFS and EH groups. On PS scales, BSP and HFS patients did not differ between them but showed higher score than HCs and EH patients. Our findings suggested that a high level of Harm Avoidance and Persistence seem to be associated with BSP, when compared with any disorders treated with BTX. An evaluation of the personality traits might help the clinicians to early identify BSP patients at greater risk of developing psychopathological disturbances.

Treatment of blepharospasm and Meige's syndrome with abo- and onabotulinumtoxinA: long-term safety and efficacy in daily clinical practice

INTRODUCTION

Thirty years after their approval, botulinum toxin injections still are the first-line therapy for blepharospasm. The aim of our study was to analyze long-term data concerning safety and efficacy in a large cohort over decades.

METHODS

Treatment data of all patients with blepharospasm and Meige´s syndrome in our outpatient clinic having undergone at least three subsequent treatment sessions with current onabotulinumtoxinA or abobotulinumtoxin A were analyzed with respect to the course of dose, effect duration, side effects, patients´ satisfaction and occurrence/reasons for treatment discontinuation.

RESULTS

The observation period was up to 18 years for onabotulinumtoxinA and 29 years for abobotulinumtoxinA with a total of 1778 and 9319 treatment sessions in 69 patients with onabotulinumtoxinA, 281 with abobotulinumtoxin A and 2 of these having used both products. The dose increased in the first years followed by a stable dose in the following years. The mean dose was 39.1/198.7 mouse units (onabotulinumtoxinA/abobotulinumtoxinA). In over 25% of all sessions, inhibition of the eyelid opening was effectively treated with pretarsal injections. The most common adverse events included ptosis (4%/5%), epiphora/sicca (4%/5%), double vision (1%/1%) and facial asymmetry (1%/1%). Reasons for therapy discontinuation were change to a nearby doctor, age, other diseases, spontaneous improvement, side effects or possible treatment failure. Only one patient was tested positive for neutralizing antibodies against botulinum toxin A.

CONCLUSION

The treatment of blepharospasm and Meige's syndrome with onabotulinumtoxinA and abobotulinumtoxinA is safe and effective, also over a long observation period of up to 29 years.

Botulinum toxin relieves anxiety and depression in patients with hemifacial spasm and blepharospasm

OBJECTIVE

To explore the efficacy of botulinum toxin type A (BTX-A) therapy in relieving anxiety and depression in patients with hemifacial spasm (HFS) and benign essential blepharospasm (BEB).

PATIENTS AND METHOD

Ninety idiopathic HFS patients and 90 BEB patients were enrolled. The anxiety and depression status were evaluated by self-rating anxiety scale (SAS) and self-rating depression scale (SDS), respectively, before and after the injection of BTX-A.

RESULTS

Before treatment, the SAS and SDS scores of HFS patients were 41.25±6.35 and 42.25±7.57, respectively. The SAS scores were 40.17±8.36 for males and 43.56±6.10 for females (P=0.031). The SDS scores were 40.25±6.46 for males and 45.48±7.31 for females (P=0.008). After treatment, the SAS and SDS scores were 30.12±4.35 and 30.58±4.89, respectively. There was a significant difference in the SAS and SDS scores before and after treatment. Before treatment, the SAS scores of male and female BEB patients were 56.45±8.75 and 60.89±9.11, respectively, and the SDS scores of male and female BEB patients were 57.90±7.93 and 60.12±8.35, respectively. After treatment, the SAS score was 38.17±3.67 and the SDS score was 38.12±4.15, with a significant difference in before and after treatment scores.

CONCLUSION

In HFS and BEB, especially in female patients, there is an association with anxiety and depression. BTX-A can improve the symptoms of anxiety and depression.

The Use of Botulinum Toxin for Treatment of the Dystonias

Dystonias are characterized by involuntary muscle contractions, twisting movements, abnormal postures, and often tremor in various body regions. However, in the last decade several studies have demonstrated that dystonias are also characterized by sensory abnormalities. While botulinum toxin is the gold standard therapy for focal dystonia, exactly how it improves this disorder is not entirely understood. Neurophysiological studies in animals and humans have clearly demonstrated that botulinum toxin improves dystonic motor manifestations by inducing chemodenervation, therefore weakening the injected muscles. In addition, neurophysiological and neuroimaging evidence also suggests that botulinum toxin modulates the activity of various neural structures in the CNS distant from the injected site, particularly cortical motor and sensory areas. Concordantly, recent studies have shown that in patients with focal dystonias botulinum toxin ameliorates sensory disturbances, including reduced spatial discrimination acuity and pain. Overall, these observations suggest that in these patients botulinum toxin-induced effects encompass complex mechanisms beyond chemodenervation of the injected muscles.

Use of Botulinum Neurotoxin in Ophthalmology

Botulinum neurotoxin (BoNT) is the first biological toxin used in the treatment of ophthalmic diseases and to decrease skin wrinkles as an aesthetic agent. When used appropriately, it weakens the force of muscular contraction and/or inhibits glandular secretion. The most common areas for botulinum toxin treatment are the upper face, including the glabella, forehead, brows, and lateral canthal lines, or crow's feet. By relaxing the muscles causing wrinkles, non-permanent results may be achieved with its use. BoNT has gained widespread use in a variety of ophthalmic diseases. The effect of BoNT is temporary, but the therapeutic benefit is usually maintained even after repeated injections. Treatment is usually well tolerated. Complications and side effects associated with the treatment are rare and temporary. Complications occur due to weakness (chemodenervation) of adjacent muscle groups, immunological mechanisms and injection technique. Current therapeutic indications, doses, complications and contraindications of BoNT use in the following disorders related to ophthalmology were investigated: aesthetic use, strabismus, blepharospasm, hemifacial spasm, eyelid retraction, entropion, lacrimal hypersecretion syndrome, and facial paralysis.

Botulinum toxin injections for the treatment of hemifacial spasm over 16 years

The aim of this study was to investigate the efficacy and side effects of botulinum toxin (BTX) in the treatment of hemifacial spasm (HFS). We also focused on the divergence between different injection techniques and commercial forms. We retrospectively evaluated 470 sessions of BTX injections administered to 68 patients with HFS. The initial time of improvement, duration and degree of improvement, and frequency and duration of adverse effects were analysed. Pretarsal and preseptal injections and Botox (Allergan, Irvine, CA, USA) and Dysport (Ipsen Biopharmaceuticals, Paris, France) brands were compared in terms of efficacy and side effects, accompanied by a review of papers which reported BTX treatment of HFS. An average of 34.5 units was used per patient. The first improvement was felt after 8 days and lasted for 14.8 weeks. Patients experienced a 73.7% improvement. In 79.7% of injections, no adverse effect was reported, in 4.9% erythema, ecchymosis, and swelling in the injection area, in 3.6% facial asymmetry, in 3.4% ptosis, in 3.2% diplopia, and in 2.3% difficulty of eye closure was detected. Patients reported 75% improvement on average after 314 sessions of pretarsal injections and 72.7% improvement after 156 sessions of preseptal injections (p=0.001). The efficacy and side effects of Botox and Dysport were similar. BTX is an effective and safe treatment option for HFS. No difference was determined between Botox and Dysport, and pretarsal injection is better than preseptal injection regarding the reported degree of improvement.

Blepharospasm: long-term treatment with either Botox®, Xeomin® or Dysport®

Botulinum toxin (BT) therapy is the treatment of choice for blepharospasm (BPS). Currently available BT type A drugs include Botox(®), Dysport(®) and Xeomin(®). Until now, there are few long-term studies on BT therapy for BPS. This is the first long-term study comparing all three major BT drugs. We collected treatment, efficacy and adverse effect data on BPS patients treated with either Botox(®), Dysport(®) or Xeomin(®) for at least eight consecutive treatments. Two hundred and eighty-eight patients (208 females, 80 males, age 62 ± 12 years) were included in this study. The treatment time was 11.2 ± 4.1 years covering 10,701 injection series. Doses were 47 ± 10 MU for Botox(®), 120 ± 35 MU for Dysport(®) and 62 ± 11 MU for Xeomin(®) (Botox(®) dose vs Xeomin(®) dose: p < 0.001, unpaired t test). 85 % of all patients had stable doses. The onset of the therapeutic effect was after 6.1 ± 3.3 days and its duration lasted 10.2 ± 3.5 weeks. The Global Clinical Improvement (GCI, 0 = no, 1 = slight, 2 = moderate, 3 = marked improvement in severity and function) as estimated by the patient was 2.5 ± 0.6. It was stable in 90% of the patients. Adverse effect frequency was 3.0% (ptosis 2.3%, dry eye 0.5%, diplopia 0.2%). None of these findings was significantly different between Botox(®), Dysport(®) and Xeomin(®). Our study, one of the largest studies on BT therapy of BPS and the study with the longest follow-up, confirms that BT therapy produces robust clinical improvement which is stable throughout the treatment time. Therapeutic effects start after 6.1 days and last for about 10 weeks before they start to vanish. With this, they are approximately 2 weeks shorter than the recommended inter-injection interval. Adverse effects were rare, mild and always transient. BT therapy is a safe and effective treatment for BSP. Shorter inter-injection intervals may improve therapeutic results.

Long-term efficacy and safety of botulinum toxin A injections to treat blepharospasm and hemifacial spasm

BACKGROUND

To evaluate efficacy and safety of botulinum toxin A injections after more than 10 consecutive years of treatment for benign essential blepharospasm and hemifacial spasm.

DESIGN

Retrospective chart review at university-affiliated hospital.

PARTICIPANTS

Study consisted of 64 patients treated with botulinum toxin A injections between October 2005 and May 2006.

METHODS

Inclusion criteria included patients treated with at least one annual botulinum toxin-A injection for more than 10 consecutive years. Data collected included diagnoses and patient characteristics, injection dates, doses administered at each visit, response scores, duration of effect, and adverse events.

MAIN OUTCOME MEASURES

Included changes in doses, response scores, duration of effects, and adverse events between the first and last botulinum toxin A injections.

RESULTS

Thirty-two of 64 patients (mean age at first injection, 57.2 ± 12.4 years; 25 women) met the inclusion criteria. The mean duration of follow up was 14.1 ± 3.1 years (range 10-20 years; mean total visits 44.4 ± 19). A higher mean injection dose per visit was administered during the last year compared with the first year (26.8 ± 10.3 vs. 22.5 ± 7.5 units, respectively) (P = 0.003). The mean durations of effect during the first and last years were 12.4 ± 7.1 and 14.6 ± 7.0 weeks, respectively (P = 0.076). There were no significant differences between genders or between benign essential blepharospasm and hemifacial spasm subgroups. The most common adverse events were ptosis, lagophthalmos and dry eye.

CONCLUSIONS

Botulinum toxin A is an effective, safe, long-term treatment for patients with benign essential blepharospasm and hemifacial spasm. Sustained treatment efficacy required higher doses; however, fewer adverse reactions developed.

Clinical features and treatment with botulinum toxin in blepharospasm: a 17-year experience

OBJECTIVE

It was to analyze clinical aspects of patients with blepharospasm, including outcomes of botulinum toxin treatment. Additionally, clinical characteristics of isolated blepharospasm were compared to those of blepharospasm plus other movement disorders.

METHODS

Clinical data recorded during 17 years were reviewed. The variables included age, gender, age of onset, past medical history, head trauma, smoking history, family history of dystonia, severity, duration of botulinum toxin relief and adverse effects.

RESULTS

A total of 125 patients were included and 75.2% were female. The mean age of onset was 54.3 years; 89.6% of the individuals started with contractions in eye region, and 39.2% of them spread to lower face or neck. Isolated blepharospasm group was compared with blepharospasm-plus group for demographic and clinical features, and therapeutic outcomes, without significant differences. Botulinum toxin treatment improved the severity of contractions (p=0.01) with low rate of side effects (14%).

CONCLUSIONS

Both groups - isolated blepharospasm and blepharospasm-plus - shared similar results concerning epidemiology, clinical features and therapeutic response to botulinum toxin.

Effect of previous botulinum neurotoxin treatment on microvascular decompression for hemifacial spasm

Object

The objective of this study was to investigate the clinical characteristics, intraoperative findings, complications, and outcomes after the first microvascular decompression (MVD) in patients with and without previous botulinum neurotoxin treatment for hemifacial spasm (HFS).

Methods

The authors analyzed 246 MVDs performed at the University of Pittsburgh Medical Center between January 1, 2000, and December 31, 2007. One hundred and seventy-six patients with HFS underwent botulinum neurotoxin injection treatment prior to first MVD (Group I), and 70 patients underwent their first MVD without previous botulinum neurotoxin treatment (Group II). Clinical outcome data were obtained immediately after the operation, at discharge, and at follow-up. Follow-up data were collected from 177 patients with a minimum follow-up period of 9 months (mean 54.48 ± 27.84 months).

Results

In 246 patients, 89.4% experienced immediate postoperative relief of spasm, 91.1% experienced relief at discharge, and 92.7% experienced relief at follow-up. There was no significant difference in outcomes and complications between Group I and Group II (p > 0.05). Preoperatively, patients in Group I had higher rates of facial weakness, tinnitus, tonus, and platysmal involvement as compared with Group II (p < 0.05). The posterior inferior cerebellar artery and vertebral artery were intraoperatively identified as the offending vessels in cases of vasculature compression in a significantly greater number of patients in Group II compared with Group I (p = 0.008 and p = 0.005, respectively, for each vessel). The lateral spread response (LSR) disappeared in 60.48% of the patients in Group I as compared with 74.19% in Group II (p > 0.05). No significant differences in complications were noted between the 2 groups.

Conclusions

Microvascular decompression is an effective and safe procedure for patients with HFS previously treated using botulinum neurotoxin. Intraoperative monitoring with LSR is an effective tool for evaluating adequate decompression.

Current and future medical treatment in primary dystonia

Dystonia is a hyperkinetic movement disorder, characterized by involuntary and sustained contractions of opposing muscles causing twisting movements and abnormal postures. It is often a disabling disorder that has a significant impact on physical and psychosocial wellbeing. The medical therapeutic armamentarium used in practice is quite extensive, but for many of these interventions formal proof of efficacy is lacking. Exceptions are the use of botulinum toxin in patients with cervical dystonia, some forms of cranial dystonia (in particular, blepharospasm) and writer's cramp; deep brain stimulation of the pallidum in generalized and segmental dystonia; and high-dose trihexyphenidyl in young patients with segmental and generalized dystonia. In order to move this field forward, we not only need better trials that examine the effect of current treatment interventions, but also a further understanding of the pathophysiology of dystonia as a first step to design and test new therapies that are targeted at the underlying biologic and neurophysiologic mechanisms.

Blepharospasm and hemifacial spasm: long-term treatment with botulinum toxin

INTRODUCTION

Our purpose is to describe the demographic, clinical and therapeutic characteristics of patients with blepharospasm (BS) and hemifacial spasm (HFS) in treatment with botulinum toxin type A (BtA).

PATIENTS AND METHODS

Retrospective analysis of patients diagnosed with BS or HFS and treated with BtA in the Neurology Department at Complejo Asistencial de Segovia between March 1991 and December 2009.

RESULTS

Different variables were collected from 34 patients with BS and 55 with HFS, of whom 44.1% and 32.7% respectively had been undergoing treatment with BtA for more than 10 years. Elapsed time from symptom onset to the first visit was 24 months in the BS group and 59.7 months in the HFS group. Diagnosis was given on the first visit for 76.5% of the BS patients and 90.7% of the HFS patients. Patients were referred by their primary care centres in 34.6% of the cases with BS and in 77.6% of the cases with HFS. The most commonly used BtA preparation was BOTOX(®) in both groups, and there were no cases of primary or secondary resistance. The median dose of BtA was raised gradually in both groups, and the increase was statistically significant during the early years of treatment. The most common side effect was ptosis (47.1% in BS, 32.5% in HFS).

CONCLUSIONS

BS and HFS are the most common facial movement disorders. The demographic and clinical characteristics and therapeutic findings from this study show that treatment with BtA is both effective and safe over the long term.

Botulinum toxin injections for blepharospasm prior to ocular surgeries

PURPOSE

The aim of this study was to show the efficiency of preoperative botulinum toxin A (Botox A) in patients with benign essential blepharospasm who were to undergo ocular surgery with local anesthesia.

MATERIALS AND METHODS

Twenty-eight benign essential blepharospasm patients who were administered unilateral Botox A prior to ocular surgery between January 2004 and May 2011 were included in this study. Eleven cases had pterygiums, ten had cataracts, and four had glaucomas, while the remaining three had aphakia. All cases' severity of spasm (stage 0-4) and eyelid closing forces (stage 1-4) were evaluated according to the Jankovic scale prior to the injection, at 3 days, 14 days, 1 month, and 3 months after Botox A injection.

RESULTS

Of the patients enrolled in the study, 16 were female and 12 were male, with an average age of 55.52 ± 1.53 years (52-65). Average onset of the Botox injection's effect was 2.8 ± 0.9 (2-5) days. Its effect lingered for about 11.5 ± 3.6 (8-22) weeks. The severity of spasm and eyelid closing forces of all the patients enrolled were compared prior to the injection at 3 and 14 days and the first and third months after the injection. There were statistically significant differences between prior to the injection and 3 days (P = 0.001), 14 days (P < 0.001) and 1 month after the injection (P < 0.001). There was no statistically significant difference between prior to the injection and 3 months after the injection (P = 0.513). Fourteen days following the injection, the surgeries were successfully performed.

CONCLUSION

Botox A administered prior to ocular surgery will control both blepharospasm and lower the risks that can be encountered before and during surgery, thus increasing the comfort of the patient and the surgeon.

Botulinum toxin treatment in upper limb spasticity: treatment consistency

This study assessed treatment consistency of botulinum toxin administration in spastic upper limbs under pragmatic conditions, as derived through stability of dosages and between injections intervals. Over a period of 8 years, 153 children (81 with bilateral spastic cerebral palsy, 72 with unilateral) were treated according to accepted, experience-based guidelines with Botox and Dysport. Treatment response was based on assessment of spasticity and attainment of pre-determined goals at 3, 6 and 12 months post each treatment. Mean age at treatment onset was 6y 4mo (SD: 4y 10mo), median F/U, 2.5 years (4 months-6 8/12 years). Number of injection sessions was 1-10; few had more than 6 sessions. In 106 (69.28%) children, more than one anatomic regions of the limb were injected. Most (56.2%), had at least two injection sessions; median time interval between the sessions was 9 months (IQR: 4-35 months, similar for unilateral and bilateral cerebral palsy, p = 0.874). Children >4 years old at the first treatment had longer intervals between sessions (25.8%) compared to younger ones (p = 0.010). The mixed effects models demonstrated that botulinum toxin dosage was stable over subsequent visits (p = 0.144) and that intermediate intervals for subsequent visits were similar to the first one (p = 0.279).

Functional end-plate recovery in long-term botulinum toxin therapy of hemifacial spasm: a nerve conduction study

Botulinum toxin type-A is currently thought to be effective and safe for hemifacial spasm (HFS). The pre-synaptic block of acetylcholine release at the neuromuscular junction induces depression of orbicularis oculi muscle compound motor action potential (CMAP). The aim of our study was to evaluate at what extent end-plate functional recovery is possible even in botulinum toxin treatments lasting up to 15 years. We examined 81 outpatients with primary HFS (mean treatment duration = 7.2 ± 4.2 years) who underwent neurophysiologic study, once clinical effect of the previous treatment had vanished. The mean CMAP amplitude, mean rectified amplitude of response 1 (R1) of the blink reflex and area of response 2 (R2) of treated orbicularis oculi muscle were measured in comparison to the controlateral side. Mean amplitude of the above mentioned parameters was slightly lower (about 20%; p < 0.001) in the treated side at the end of the follow-up period (4.7 ± 1.7 months). The CMAP amplitude reduction weakly correlated with the interval from last treatment, while other neurophysiologic parameters did not change due to treatment duration or total toxin amount. Our study demonstrates that botulinum toxin affects compound motor action potential and blink-reflex responses for at least 4-5 months in HFS patients. The residual block is slight and does not increase with repeated injections after several years of treatment. Our study, beside confirming the long-term efficacy of botulinum toxin treatment for HFS, provides neurophysiologic evidence that therapeutic effect may be obtained without hindering the regenerative potential of the nerve-muscle complex.