Quantitative changes in botulinum toxin a treatment over time in patients with essential blepharospasm and idiopathic hemifacial spasm

Health-related quality of life of daily-life-affected benign essential blepharospasm: Multi-center observational study

PURPOSE

To compare Thais' health-related quality of life (HRQOL) and severity grading, efficacy and safety in daily-life-affected benign essential blepharospasm (BEB) patients at baseline and after Botulinum toxin type A (BTX-A) treatment.

DESIGN

Prospective-observational study.

PARTICIPANTS

BEB patients with Jankovic rating scale (JRS) at least 3 in both severity and frequency graded from 14 institutes nationwide were included from August 2020 to June 2021.

METHODS

Demographic data, HRQOL evaluated by the Thai version of EQ-5D-5L and NEI-VFQ-25 questionnaires, and severity grading score evaluated by Jankovic rating scale (JRS) at baseline, 1, and 3 months after the treatment were collected. The impact of the BTX-A injections and their complications were recorded.

RESULTS

184 daily-life-affected BEB patients were enrolled; 159 patients (86.4%) had complete data with a mean age of 61.40±10.09 years. About 88.05% were female, and 10.1% were newly diagnosed. Most of the patients had bilateral involvement (96.9%) and 12.6% had history of BEB-related accident. After BTX-A treatment, HRQOL improved significantly in 4 dimensions of EQ-5D-5L, except self-care. The EQ_VAS (mean±SD) was 64.54±19.27, 75.13±15.37, 73.8±15.85 (p<0.001) and EQ-5D-5L utility score was 0.748±0.23, 0.824±0.19 and 0.807±0.19 at baseline, 1, 3 months after treatment, respectively. From NEI-VFQ-25, HRQOL also improved in all dimensions, except eye pain. The JRS improved in all patients. Self-reported minor adverse events were 22.6%, which mostly resolved within the first month.

CONCLUSION

Daily-life-affected BEB impacted HRQOL in most dimensions from both generic and visual-specific questionnaires. BTX-A treatment not only decreased disease severity, but also improved quality of life.

Nonlinear Changes in Botulinum Toxin Treatment of Task-Specific Dystonia during Long-Term Treatment

Botulinum toxin (BoTX) is the standard treatment for task-specific dystonias (TSDs) such as musician’s dystonia (MD). Our aim was to assess the long-term changes in BoTX treatment in a highly homogeneous and, to our knowledge, largest group of MD patients with respect to the following parameters: (1) absolute and (2) relative BoTX dosage, (3) number of treated muscles, and (4) inter-injection interval. We retrospectively assessed a treatment period of 20 years in 233 patients, who had received a cumulative dose of 68,540 MU of BoTX in 1819 treatment sessions, performed by two neurologists. Nonlinear correlation was used to analyze changes in the parameters over the course of repeated treatments. Post-hoc we applied a median-split to classify two subgroups (high-BoTX, low-BoTX) depending on the total amount of BoTX needed during treatment. Across all patients, we found a decrease of dosage for the first approximately 25 treatments with an increase afterwards. The number of muscles and inter-injection intervals increased with time with a discrete decrease of inter-injection intervals after about 35 treatments. Subgroup differences were observed in the amount of BoTX and inter-injection intervals, with continuously increasing inter-injection intervals and decreasing BoTX dosage in the low-BTX group. Both groups showed a continuously increasing number of injected muscles. In summary, we found nonlinear changes of BoTX dosage and inter-injection intervals and a continuously increasing number of injected muscles with treatment duration in TSD-patients. Furthermore, we, for the first time, identified two subgroups with distinct differences. Increasing inter-injection intervals and decreasing BoTX dosages in the low-BoTX group indicated improvement of symptoms with continued treatment. Continually increasing BoTX dosages with unchanged inter-injection intervals in the high-BoTX group indicated deterioration.

Botulinum Toxin in Movement Disorders: An Update

Since its initial approval in 1989 by the US Food and Drug Administration for the treatment of blepharospasm and other facial spasms, botulinum toxin (BoNT) has evolved into a therapeutic modality for a variety of neurological and non-neurological disorders. With respect to neurologic movement disorders, BoNT has been reported to be effective for the treatment of dystonia, bruxism, tremors, tics, myoclonus, restless legs syndrome, tardive dyskinesia, and a variety of symptoms associated with Parkinson’s disease. More recently, research with BoNT has expanded beyond its use as a powerful muscle relaxant and a peripherally active drug to its potential central nervous system applications in the treatment of neurodegenerative disorders. Although BoNT is the most potent biologic toxin, when it is administered by knowledgeable and experienced clinicians, it is one of the safest therapeutic agents in clinical use. The primary aim of this article is to provide an update on recent advances in BoNT research with a focus on novel applications in the treatment of movement disorders. This comprehensive review of the literature provides a critical review of evidence-based clinical trials and highlights recent innovative pilot studies.

Characteristics of tear abnormalities associated with benign essential blepharospasm and amelioration by means of botulinum toxin type A treatment

PURPOSE

To investigate the characteristics of tear abnormalities with benign essential blepharospasm (BEB) and the effect of botulinum toxin type A (BTX-A) treatment.

STUDY DESIGN

Prospective and clinical study.

METHODS

Forty eyes of 40 patients (12 men and 28 women, ages 63.5 ±12.9) with BEB and tear abnormalities were enrolled.

RESULTS

The average scores for subjective symptoms as evaluated by the visual analog scale (VAS) were 46.3 and Dry Eye-Related Quality-of-Life Score (DEQS) were 63.7. The fluorescein breakup time (FBUT) was 2.7 ± 1.6 sec. Among fluorescein breakup patterns (FBUPs), dimple break, with the corresponding mechanism of decreased wettability was the most frequent, observed in 29 eyes (73%). The NEI score was 0.4 ± 0.7 and the van Bijesterveld score was 0.6 ± 0.8; the Schirmer 1 test value was 13.1 ± 9.4 mm. Eighteen patients received BTX-A treatment, and significant improvement was found in severity of subjective symptoms both on VAS and DEQS as well as for FBUT. The main FBUPs changed from dimple break to random break.

CONCLUSION

Tear abnormalities seen in BEB correspond to short BUT-type dry eye (DE), subclassified into decreased wettability DE in view of FBUPs.

Efficacy and Safety of Long-Term Therapy with Type A Botulinum Toxin in Patients with Blepharospasm

Blepharospasm (BPS) is one of the most frequent types of facial dystonia and, at the same time, one of the most disabling, being able to trigger functional blindness if not treated. Our aim with this work was to evaluate the efficacy and safety of long-term onabotulinum A toxin (BAT) treatment in a cohort of patients with BPS. The retrospective study was conducted on consecutive patients with BPS treated with subcutaneous BAT. The selection of muscles and dose was made based on each patient's needs. The clinical and demographic characteristics, number of sessions, dose, duration and effectiveness of treatment, and adverse events were analysed. 130 patients were included in the study. The median (95% confidence interval) length of follow-up was 14 (13-15.6) years with an average of 20.5 sessions (range from 10 to 57). Regarding the efficacy of the treatment, 114 (87.7%) experienced satisfactory results with functional and aesthetics recovery. Patient evaluation of global response suggested a clear improvement without adverse events in 72 (55.4%) patients. Adverse events developed at least once during the treatment in 39% of patients, with transient ptosis and haematoma the most common reported both by physician and patient. The results of our study suggest that botulin toxin A is a safe and effective long-term treatment for blepharospasm with mild, transient and well-tolerated side effects when they appear.

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.

Increase lipid tear thickness after botulinum neurotoxin A injection in patients with blepharospasm and hemifacial spasm

The aim of this study was to investigate changes in the tear film lipid layer thickness (LLT) and aqueous tear production after botulinum neurotoxin A (BoNT) injection in patients with benign essential blepharospasm (BEB) and hemifacial spasm (HFS). Eleven and six patients with BEB and HFS, respectively, who received BoNT injection were consecutively enrolled in this prospective study. The blepharospasm disability index (BSDI), blink pattern, dry eye symptoms, Schirmer test 1 findings, LLT, eyelid performance, and corneal integrity were evaluated before and after treatment. Both BEB and HSF patients experienced remarkable relief from spasms and ocular discomfort after BoNT injection. LLT, the partial blink rate, the snap-back time, the lid distraction distance, and lateral canthal laxity were significantly increased at 1 month after treatment. There were no significant changes in Schirmer test 1 findings and meibomian gland dropout. Our findings suggest that LLT, a decisive factor for tear film stability, significantly increases at 1 month after BoNT injection for BEB and HFS. A decrease in BSDI and an increase in the snap-back time may contribute to the increase in LLT; this mechanism is probably responsible for the relief from dryness after BoNT injection in patients with facial movement disorders.

An investigation into quality of life improvement in patients undergoing microvascular decompression for hemifacial spasm

OBJECTIVE Hemifacial spasm (HFS) is a movement disorder characterized by involuntary spasms of the facial muscles, and it can negatively impact quality of life (QOL). This retrospective study and systematic review with meta-analysis was conducted to investigate the QOL in patients with HFS following intervention with microvascular decompression (MVD) and botulinum toxin (BT). METHODS In the retrospective analysis, a QOL questionnaire was administered to all patients undergoing MVD performed by a single surgeon. The QOL questionnaire included unique questions developed based on the authors' experience with HFS patients in addition to the health-related QOL HFS-8 questionnaire. The authors also report on a systematic review of the English literature providing outcomes and complications in patients with HFS undergoing treatment with either MVD or BT. RESULTS Regarding the retrospective analysis, 242 of 331 patients completed the questionnaire. The mean score of the 10 QOL questions improved from 22.78 (SD 9.83) to 2.17 (SD 5.75) following MVD (p < 0.001). There was significant improvement across all subscales of the questionnaire between pre- and postoperative responses (p < 0.001). Regarding the systematic review, it is reported that approximately 90% of patients undergoing MVD for HFS experience a complete recovery from symptoms, whereas the mean peak improvement of symptoms following treatment with BT is 77%. Furthermore, patients undergoing MVD reported a greater improvement in the mean supplemental index of QOL as compared with patients receiving BT therapy. CONCLUSIONS Microvascular decompression offers a significant improvement in QOL in well-selected patients suffering from HFS, and may offer an increased benefit for QOL over BT injections.

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.

Long-term efficacy, safety, and side effect profile of botulinum toxin in dystonia: a 20-year follow-up

Most long-term studies of the efficacy and safety profile of botulinum toxin (BoNT) in the treatment of dystonia are limited by lack of objective assessments, relatively small sample size, or short follow-up periods. We present one of the longest follow-up studies of BoNT treatment. This is a retrospective, longitudinal study that analyzes data on 89 patients treated with BoNT for dystonia at our Movement Disorders Clinic for up to 26 years (mean follow-up period of 18.5 years). The mean ages at the time of the first and last injections were 49 and 68 years old, respectively. The most common diagnoses were cervical dystonia (N = 51), blepharospasm (N = 34), and oromandibular dystonia (N = 26). The total number of onabotulinumtoxinA units received during the first injection was 140.3 as compared to 224.5 at the last injection (p < 0.0001). The global response effect was 3.18 after the first injection session and 3.57 after the last injection (p < 0.0001). The duration of response after the initial injection session and at the last injection was 16.33 weeks versus 19.42 weeks (p 0.0037), respectively. Adverse events, typically related to injection site, were reported in 19% of the visits. This series of dystonia patients with the longest reported treatment with BoNT provide evidence that in selected patients repeated chemodenervation is associated with sustained symptomatic benefit, decreased latency effect, and prolonged duration of therapeutic response. Despite the higher requirement of mean units per visit over time, only 19% of all treatment cycles are associated with adverse, but tolerable, side effects.

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.

Long-term efficacy and safety of botulinum toxin injections in dystonia

Local chemodenervation with botulinum toxin (BoNT) injections to relax abnormally contracting muscles has been shown to be an effective and well-tolerated treatment in a variety of movement disorders and other neurological and non-neurological disorders. Despite almost 30 years of therapeutic use, there are only few studies of patients treated with BoNT injections over long period of time. These published data clearly support the conclusion that BoNT not only provides safe and effective symptomatic relief of dystonia but also long-term benefit and possibly even favorably modifying the natural history of this disease. The adverse events associated with chronic, periodic exposure to BoNT injections are generally minor and self-limiting. With the chronic use of BoNT and an expanding list of therapeutic indications, there is a need to carefully examine the existing data on the long-term efficacy and safety of BoNT. In this review we will highlight some of the aspects of long-term effects of BoNT, including efficacy, safety, and immunogenicity.

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.

The effect of bangerter occlusion foils on blepharospasm and hemifacial spasm in occlusion-positive and occlusion-negative patients

Objective:

To test the hypothesis that occlusion-positive (OP) patients with blepharospasm (BEB) or hemifacial spasm (HFS) will benefit from a Bangerter occlusion foil (BOF), compared to occlusion-negative (ON) patients. OP/ON was based on immediate improvement in spasm with placement of a hand in front of either eye.

Design:

Prospective non-randomised single-centre pilot study.

Participants:

Fifteen-patients (6 BEB, 9 HFS).

Methods:

Patients were identified as OP or ON and wore highest-density BOF tolerable over one spectacle lens for 1 month. Outcomes were assessed at 1 month.

Main Outcome Measures:

Validated quality-of-life questionnaire (CDQ-24), scores of blink-rate and spasm severity assessed by two observers from video-recordings.

Results:

OP group had mean improvement in all scores. There was no change or worsening of scores in the ON group. In both BEB and HFS, more OP patients reported subjective benefit from wearing a foil (2 of 4 BEB, and 2 of 2 HFS) compared to the ON group (0 of 2 BEB, and 1 of 7 HFS).

Conclusion:

OP patients with BEB and HFS are more likely to experience improvement in spasms from wearing a BOF compared to ON patients. The occlusion test should be considered on all patients with BEB or HFS.

Long-term use of botulinum toxin type A in children with cerebral palsy: treatment consistency

At the University Hospital of Pellenberg (Belgium), more than 1000 patients have been treated with Botulinum toxin type A (BTX-A) over the last decade. Ten percent of these patients (n=106) received multiple (at least four times), multi-level, high-dosage treatments. The aim of this study was to evaluate the stability of dosage and treatment intervals in long-term, multi-level, high-dosage treated children with cerebral palsy and to evaluate the evidence for a safe and stable response to this treatment. Data on disease, age, dosage and target muscles were extracted for each treatment session of 106 patients who received multiple BTX-A treatment sessions. Patients had a follow-up of 4y 6mo (range 1y 8mo-8y 9mo) on average and received 4 to 12 BTX-A treatments within the period of January 1996 and December 2005. Patients received a mean dosage of 23.5+/-5.2U/kgbw at first treatment with stable subsequent values. Mean dosages for children with diplegia, hemiplegia and quadriplegia were 24.5+/-4.7U/kgbw, 15.9+/-3.7U/kgbw and 22.0+/-4.8U/kgbw, respectively. Mean age at first treatment was 4y 6mo (range 1y 11mo-18y 10mo) with a majority of patients (76.4%) first treated within 2 and 4y of age. Treatment intervals of approximately 1y remained stable within four, five and six subsequent treatments. Long-term, high-dosage, multi-level BTX-A applications can be considered as a safe and stable treatment option for children with cerebral palsy and the formation of antibodies, responsible for secondary non-response, can be indirectly precluded.

Long-term efficacy of botulinum toxin A for treatment of blepharospasm, hemifacial spasm, and spastic entropion: a multicentre study using two drug-dose escalation indexes

PURPOSE

To investigate the long-term effectiveness and safety of botulinum neurotoxin A (BoNT-A) treatment in patients with blepharospasm (BEB), hemifacial spasm (HFS), and entropion (EN) and to use for the first time two modified indexes, 'botulin toxin escalation index-U' (BEI-U) and 'botulin toxin escalation index percentage' (BEI-%), in the dose-escalation evaluation.

METHODS

All patients in this multicentre study were followed for at least 10 years and main outcomes were clinical efficacy, duration of relief, BEI-U and BEI-%, and frequency of adverse events.

RESULTS

BEB, HFS, and EN patients received a mean BoNT-A dose with a significant inter-group difference (P<0.0005, respectively). The mean (+/-SD) effect duration was statistically different (P=0.009) among three patient groups. Regarding the BoNT-A escalation indexes, the mean (+/-SD) values of BEI-U and BEI-% were statistically different (P=0.035 and 0.047, respectively) among the three groups. In BEB patients, the BEI-% was significantly increased in younger compared with older patients (P=0.008). The most frequent adverse events were upper lid ptosis, diplopia, ecchymosis, and localized bruising.

CONCLUSIONS

This long-term multicentre study supports a high efficacy and good safety profile of BoNT-A for treatment of BEB, HFS, and EN. The BEI indexes indicate a significantly greater BoNT-A-dose escalation for BEB patients compared with HFS or EN patients and a significantly greater BEI-% in younger vsolder BEB patients. These results confirm a greater efficacy in the elderly and provide a framework for long-term studies with a more flexible and reliable evaluation of drug-dose escalation.

What is new in the era of focal dystonia treatment? Botulinum injections and more

PURPOSE OF REVIEW

The treatment options for the management of dystonias continue to evolve and improve. Clinical outcomes, however, are not predictably consistent using a single treatment regimen in all patients.

RECENT FINDINGS

Botulinum toxin is still considered the best treatment option for the treatment of focal dystonias: blepharospasm, hemifacial spasm, and apraxia of eyelid opening. New findings indicate that physicians may be a little more aggressive with the dosage when the disease progresses. A new formulation of botulinum toxin has been produced that includes no proteins and may address the immunoresistance that can occur with prolonged use. Additional systemic medications may be helpful as adjuncts only in selected cases. Improved surgical techniques are now more successful and cause fewer complications. Therefore, many refractory cases are now offered a surgical approach alone or in combination with botulinum toxin.

SUMMARY

There have been recent therapeutic developments in the treatment of ocular dystonias.

Safety and efficacy of botulinum toxin type A following long-term use

Botulinum toxin serotype A (BoNT-A) has long heritage of use leading to confidence in its safety and efficacy. The application of BoNT-A does not lead to persistent histological changes in the nerve terminal or the target muscle. Clinical trials defined the safety and tolerability profile of BoNT-A across common therapeutic indications and showed an incidence of adverse events of approximately 25% in the BoNT-A-treated group compared with 15% in the control group. Focal weakness was the only adverse event to occur more often following BoNT-A treatment. Long-term BoNT-A administration has been assessed in various treatment settings, with the level and duration of BoNT-A efficacy response being maintained over repeated rounds of injection with no major safety concerns. The treatment of children with cerebral palsy often require long-term, repeated, multimuscle BoNT-A injections that lead to the administration of comparably higher toxin doses. Despite the high total body doses used, their distribution over multiple muscles and injection sites means that systemic side effects are rare. Recent formulation changes have reduced the incidence of antibody development following treatment with BOTOX. These findings show long-term BoNT-A treatment to be both safe and efficacious for a wide variety of indications.

Effectiveness of repeated treatment with botulinum toxin type A across different conditions

This review assessed the overall effectiveness of repeated treatments with botulinum toxin type A (BoNTA) across different conditions, as documented in the published literature. Forty-four original research articles reporting on 16 different conditions were identified that included data on the duration or efficacy of multiple treatments with BoNTA. All of the 44 studies found sustained or enhanced improvement in efficacy and/or duration over the follow-up period, which ranged from a few treatments to more than 10 years. Dosages did not change over time in 22 of the studies, increased in 4 studies, were not reported over time in 17 studies, and tended to increase then decrease in one study. Seven studies reported a statistically significant increase in the efficacy or duration of BoNTA over time. Results suggest that continued benefit with repeated BoNTA treatment is widely reported in the literature.

Use of high-dose botulinum A toxin in benign essential blepharospasm: is too high too much?

BACKGROUND

Botulinum toxin (Botox) is the mainstay treatment for benign essential blepharospasm. Current treatment practice appears restricted by several reports demonstrating adverse effects and resistance to high-frequency, higher-dose therapy. This study aimed to explore whether high-dose, high-frequency treatments could be used without developing secondary resistance and without significant side-effects in patients refractory to conventional Botox doses.

METHODS

From a cohort of 120 patients being treated with Botox therapy for benign essential blepharospasm and idiopathic hemifacial spasm, case notes from six patients were retrospectively examined. In these patients, therapy had exceeded the recommended 50 units per side for a duration greater than 12 months and at less than 3 monthly intervals. Patterns in subjective severity grading and percentage of improvement as well as reported side-effects were analysed.

RESULTS

All patients described greater than 60% improvement and 0-2 severity grading over a 3- to 15-year period with no evidence of secondary resistance. Side-effects were minor, transient and less frequently reported at higher doses.

CONCLUSION

In a select group of patients, Botox therapy can be used effectively at doses higher than recommended over long periods with minimal side-effects and little evidence of secondary resistance.

Botulinum toxin therapy of hemifacial spasm: comparing different therapeutic preparations

Hemifacial spasm (HFS) is characterized by involuntary irregular clonic or tonic movements of the muscles innervated by cranial nerve VII on one side of the face, and is most often a result of vascular compression of the facial nerve at the root exit zone (Muscle and Nerve 1998;21:1740). Disability associated with this disorder ranges from social embarrassment to interference with vision resulting from involuntary eye closure. Treatment of HFS most often involves botulinum toxin injections, but may also include medications and surgery. We describe treatment with the three types of botulinum toxin currently commercially available--Botox, Dysport and Myobloc/NeuroBloc.

Botulinum toxin in blepharospasm and oromandibular dystonia: comparing different botulinum toxin preparations

Amongst all regions of the body, the craniocervical region is the one most frequently affected by dystonia. Whilst blepharospasm--involuntary bilateral eye closure--is produced by spasmodic contractions of the orbicularis oculi muscles, oromandibular dystonia may cause jaw closure with trismus and bruxism, or involuntary jaw opening or deviation, interfering with speaking and chewing. Both forms of dystonia can be effectively treated with botulinum toxin injection. This article summarizes injection techniques in both forms of dystonia and compares doses, potency and efficacy of different commercially available toxins, including Botox, Dysport, Xeomin and Myobloc/NeuroBloc.