Placebo-controlled double-blind cross-over study of botulinum A toxin in hemifacial spasm

Therapeutic Approach to Botulinum Injections for Hemifacial Spasm, Synkinesis and Blepharospasm

The aim of this study was to show our therapeutic outcome of botulinum injection to the facial muscles and thereby to find the best therapeutic concept which should be embraced. The decision to treat the lower eyelid with 1-point or 2-points injection was randomly taken as there is no consensus regarding this debate. Injections of the lateral end of the upper eyelid were performed more laterally to the conventional injection point, just lateral to the conjunction of the upper and lower eyelids. Twenty-three patients (12 hemifacial spasm, 6 blepharospasm, 5 post facial palsy synkinesis) were enrolled. Data were retrieved from 112 visits between 2019 and 2022. Overall, 84.9% of the treatments had moderate or marked improvement. The most common side effect was facial weakness (11.8%). Neither ptosis nor diplopia were noted. Two-points regimen in the lower eyelid was associated with a lower risk of facial weakness (p = 0.01), compared to 1-point regimen, with a better therapeutic outcome as reflected by more favorable PGI-C scores (p = 0.04). Injection of the pretarsal segment of the upper eyelid, just onto or even lateral to the conjunction of the upper and lower eyelids, lowers the risk of ptosis.

Validation of a new hemifacial spasm grading questionnaire (HFS score) assessing clinical and quality of life parameters

Validation of the new hemifacial spasm (HFS) questionnaire “HFS score” that captures both clinical (HFS clinical) and health-related quality of life (HRQOL) parameters (HFS subjective) in one tool and comparison with a global HRQOL questionnaire. Cross sectional, prospective validation study including 143 subjects (62 HFS patients and 81 healthy volunteers) from the University Eye Hospital Bonn. Patients were interviewed with the new HFS score and the SF-12 questionnaire prior to and 3 weeks after Botulinum neurotoxin A (BoNT-A) injection. All HRQOL-related questions (HFS subjective) were answered on a visual analogue scale (VAS) ranging from 0 (no complaints) to 100% (maximum complaints) by the patients themselves. Reproducibility was tested in a study extension with 10 patients by repeat interviews (telephone/personal). The new HFS score questionnaire provided a reliable clinical assessment and demonstrated that BoNT-A therapy significantly reduced frequency and severity of eye and cheek spasms (p < 0.001; Wilcoxon test). Relevant aspects of HRQOL of HFS patients were assessed with high accuracy and sensitivity. Significant improvements were achieved after BoNT-A injection in five out of eight HRQOL parameters (p ≤ 0.02; Wilcoxon test). Cronbach’s alpha of 0.818 demonstrated good internal consistency. Telephone survey provided comparable results to personal interviews. This new sensitive and specific HFS score seems a reliable instrument to monitor BoNT therapy and customize it to the needs of the individual HFS patient—in clinical studies and daily clinical practice.

[Hemifacial spasm]

Hemifacial spasm (HFS), or facial hemispasm, is a paroxysmal hyperkinetic disorder involving muscles innervated by the facial nerve, mainly on the one hand. The development of HFS is based on neurovascular conflict. However, it is impossible to explain the clinical manifestations of HFS only by nerve compression. Both peripheral and central mechanisms are involved in the generation of HFS, with the formation of ephaptic transmission, antidromic excitation, primary or secondary hyper-excitability of the nuclear and supranuclear level of innervation. Two treatment methods are pathogenetically justified: microvascular decompression (MVD) and botulinum toxin (BTX) injections. The effectiveness of MVD is 95.37% with full or partial recovery. The recurrence rate does not exceed 2.4%. Facial nerve paralysis (2.7-22.5%) and hearing loss (1.9-20%) are the most common complications of treatment with the use of the MVD for HFS with partial or complete cure in most cases. Botulinum toxin injection chemo-denervation is a first-line treatment of primary and secondary HFS. HFS is an officially registered indication for the drug dysport (abobotulotoxin) (ABO) in the Russian Federation. Total doses of ABO ranged from 25 to 150 units for one side depending on the severity of the clinical manifestations. Studies demonstrate the statistically significant benefits of HFC treatment with ABO. ABO is generally well-tolerated. Adverse events (up to 3.6%) are transient and include ptosis, lacrimation, blurred vision, double vision, dry eyes and weak facial muscles.

Botulinum Toxin Treatment of Movement Disorders

Botulinum neurotoxins (BoNTs) are now among the most widely used therapeutic agents in clinical medicine with indications applied to the fields of movement disorders, pain disorders, and autonomic dysfunction. In this literature review, the efficacy and utility of BoNTs in the field of movement disorders are assessed using the criteria of the Guideline Development Subcommittee of the American Academy of Neurology. The literature supports a level A efficacy (established) for BoNT therapy in cervical dystonia and a level B efficacy (probably effective) for blepharospasm, hemifacial spasm, laryngeal dystonia (spasmodic dysphonia), task-specific dystonias, essential tremor, and Parkinson rest tremor. It is the view of movement disorder experts, however, that despite the level B efficacy, BoNTs should be considered treatment of first choice for blepharospasm, hemifacial spasm, laryngeal, and task-specific dystonias. The emerging data on motor and vocal tics of Tourette syndrome and oromandibular dystonias are encouraging but the current level of efficacy is U (undetermined) due to lack of published high-quality studies.

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.

Botulinum toxin in hemifacial spasm: the challenge to assess the effect of treatment

Hemifacial spasm is characterized by intermittent tonic or clonic contractions of the muscles supplied by the facial nerve. Although vision is less impaired than in patients with blepharospasm, the disease can impose significant psychosocial burden on patient's life. Botulinum toxin (BoNT) is the well-established pharmacotherapy of choice, but evidence from controlled clinical trials is sparse. There is a broad variety of rating scales used in clinical studies with BoNT and obviously no consensus has been reached how to assess treatment outcome in hemifacial spasm. Clinical rating scales focusing on objective function were used in a couple of controlled studies with BoNT and were appropriate to discriminate between BoNTA and placebo. But it has not been shown that they would be sensitive enough to detect minor differences between several BoNT formulations. Although most of the clinical scales consist of a five-point rating, the descriptors for the ordinal numbers are not necessarily the same so that the results of different clinical studies are not comparable to each other. The main disadvantage of clinical scales is that they do not take into account patient's perspective of disability and impact on daily life. For this reason some clinical studies applied health-related quality of life (HRQoL) questionnaires to assess efficacy, and one research group worked on the development of disease-specific tools. Although these HRQoL questionnaires have been validated and a good correlation to disease severity could be demonstrated, they are far from having become an established variable for efficacy assessment in hemifacial spasm trials. The challenge remains to establish tools which are appropriate to rate BoNT treatment effects in hemifacial spasm. Currently, it is virtually impossible to identify one rating scale which can cover all relevant aspects of the disorder. In consequence we recommend the implementation of a combination of different rating scales which address functional impairment as well as those issues which are most important to patients. Further research is needed to standardize and validate rating scales for hemifacial spasm in clinical studies.