Clinical outcomes of individualized botulinum neurotoxin type A injection techniques in patients with essential blepharospasm

Clinical implications of genetic polymorphisms in blepharospasm

The possible genetic variants associated with blepharospasm (BSP) and facial dystonia have been investigated. Although genetic variants associated with BSP have been extensively studied, the contribution of single-nucleotide polymorphisms towards this condition remains poorly understood. In addition, the etiology of BSP remains to be fully elucidated. Therefore, the present study aimed to assess the role of polymorphisms in the torsin 1A (TOR1A), dopamine receptor D (DRD)2 and DRD5 genes in South Korean patients with BSP. Furthermore, the role of genetic variants of these three aforementioned genes was investigated. A prospective case-control study was established, where 56 patients with BSP and 115 healthy controls were recruited at the Department of Ophthalmology of CHA Bundang Medical Center (Seongnam, South Korea) using single nucleotide polymorphisms analysis by real-time PCR. The TOR1A rs1182CC/DRD5 rs6283TC genotype combination was found to be associated with decreased BSP risk [adjusted odds ratio (AOR), 0.288; P=0.013]. DRD5 rs6283 was observed to be associated with the periocular type of BSP in the co-dominant (for the TC genotype; AOR, 0.370; P=0.029) and dominant models (AOR, 0.406; P=0.029). The recessive model of TOR1A rs1801968 (AOR, 0.245; P=0.030), and the recessive (AOR, 0.245; P=0.029) and over-dominant models (AOR, 2.437; P=0.019) of DRD2 rs1800497 were found to be associated with superior responses to botulinum neurotoxin A (BoNT) treatment. By contrast, dominant (AOR, 0.205; P=0.034) and additive (AOR, 0.227; P=0.030) models of DRD5 rs6283 were associated with poor responses to BoNT treatment. To conclude, these results suggested that DRD2 rs1800497 can confer genetic susceptibility to BSP responses to BoNT treatment, whereas the TOR1A rs1182CC/DRD5 rs6283TC genotype combination appeared to contribute to the association with BoNT efficacy in BSP.

Postmarketing safety surveillance data reveals protective effects of botulinum toxin injections against incident anxiety

Randomized controlled trials (RCTs) have shown an antidepressant effect of glabellar botulinum toxin (BoNT) injections. In the FDA Adverse Event Reporting System (FAERS) database, BoNT injection is associated with reduced incidence rates of depression across various non-psychiatric indications, which confirms the previous findings independently of specific expectations to an antidepressant effect of BoNT. The rationale of using BoNT to treat depression is to interrupt proprioceptive body feedback that may reinforce negative emotions. Negative emotions also occur in other mental disorders, suggesting a transdiagnostic therapeutic potential of BoNT in psychiatry. Here we report an analysis of the FAERS database, in which we found that, compared to alternative treatments, BoNT injections were associated with lower incidence of anxiety symptoms and related disorders. Among seven indications/injection sites, we found this protective effect of BoNT in cosmetic use/facial muscles, migraine/facial and head muscles, spasms and spasticity/upper and lower limbs, torticollis and neck pain/neck muscles, and sialorrhea/parotid and submandibular glands (reporting odds ratios 0.79-0.27). These findings are encouraging for possible future RCTs on the use of BoNT as a treatment for anxiety and related disorders.

Blink index as a response predictor of blepharospasm to botulinum neurotoxin-A treatment

PURPOSE

We investigated the blink profiles and blink index using ocular surface interferometer in the patients with blepharospasm (BSP) and identified points to consider predictive factor after BSP treatment.

METHODS

In total, 117 eyelids of 59 elderly patients and 20 eyelids of 10 age-matched control group were studied. All BSP patients applied botulinum toxin-A (BoNT-A) injection for treatment of BSP. An ocular surface interferometer (LipiView; TearScience, Morrisville, NC, USA) was used to measure blink profile and blink index; total and incomplete blinks/20 s, and the partial blink ratio (PBR). Eyelid blink time (including lid closing time, closure time, lid opening time), interblink times (IBT), closing speeds (OS), and opening speeds (OS) were analyzed using 600 blinks recorded over 20 s.

RESULTS

Total blink rate was significantly higher in BSP patients compared to the age-matched control group (p = .029) but other time-related and speed-related index including interpalpebral fissure, PBR, blink time, closure time (CT), interblink time, CS, and OS were not significantly different. In the responder of BSP patients, the average age was higher, CT was shorter, CS was faster than nonresponder (age; p = .016, CT; p < .001, CS; p = .042).

CONCLUSION

The blink index by analyzing the blink profile using ocular surface interferometer, and this blink index may be used as a predictive factor for evaluating the clinical response after BoNT-A injection in blepharospasm patients.

Botulinum toxin for benign essential blepharospasm: A systematic review and an algorithmic approach

BACKGROUND

Currently, there is no standardised approach for benign essential blepharospasm treatment with botulinum toxin, and controversies still exist regarding this subject.

OBJECTIVE

The objective of this systematic review is to summarise and compare all the published data regarding benign essential blepharospasm treatment with botulinum toxin.

METHODS

On October 3, 2018, an online search of the Medline database was conducted. All articles with a detailed description of their botulinum toxin injection technique for benign essential blepharospasm were included in this review.

RESULTS

Five studies were selected for inclusion with a total of 854 patients. Four of the included studies used onabotulinumtoxin A and one study used abobotulinumtoxin A. All studies injected the pretarsal orbicularis occuli muscle. The preseptal orbicularis occuli was injected in four studies, and the preorbital muscle in three studies. The most commonly used method of evaluation was the Jankovic Rating Scale. Adverse events were transient, and dose related. Ptosis was more frequently encountered with the preseptal orbicularis injections.

CONCLUSION

Botulinum toxin injection for benign essential blepharospasm is a non-invasive and safe procedure. The pretarsal muscle should be considered as the key component when treating benign essential blepharospasm with botulinum toxin. We developed an algorithmic approach to the treatment of benign essential blepharospasm with botulinum toxin. However, further randomised controlled trials are warranted.

Long-term Efficacy of Botulinum Neurotoxin-A Treatment for Essential Blepharospasm

Purpose

In the present study, we investigated the treatment efficacy and clinical outcomes of botulinum neurotoxin-A (BoNT-A) administered for longer than 5 years to patients with essential blepharospasm.

Methods

We retrospectively reviewed 19 patients (male : female = 8 : 11) diagnosed with essential blepharospasm between March 2006 and July 2016 who underwent BoNT-A injections for over 5 years and were followed. Efficacy of 297 injections of Botox (n = 162), Meditoxin (n = 75), Hugel-tox (n = 40), or Dysport (n = 20) was based on the symptom improvement score at the final injection (−1, worse; 0, same; 1, better). Injection dose (botox unit), duration of efficacy (months), and adverse events were also investigated.

Results

Based on product type, significant differences in patient age (59.3 ± 9.8 years), disease period (5.0 ± 5.4 years), number of botulinum neurotoxin injections before visiting our clinic (1.6 ± 2.6), and follow-up period (7.2 ± 1.6 years) were not observed. Treatment efficacy score and injection dose of repetitive injections were 0.1 ± 0.5 and 39.1 ± 4.0 units, respectively, and did not show significant differences with repeated injections. Duration of response was 5.9 ± 5.4 months, but this significantly decreased as the injections were repeated (p < 0.01). Among the 297 injections, adverse events occurred 12 times (4.0%) with no severe sequelae.

Conclusions

In this study, we showed that repetitive, long-term BoNT-A injections are considered a stable and effective treatment for essential blepharospasm in terms of consistent injection dose and maintenance of treatment efficacy. However, the duration of long-term efficacy could be decreased in patients injected repetitively.

Vitreous hemorrhage and Rhegmatogenous retinal detachment that developed after botulinum toxin injection to the extraocular muscle: case report

Background

The authors report a case of a rare complication that occurred after botulinum toxin injection to the extraocular muscle, which was easily overlooked and successfully corrected by surgery.

Case presentation

A 34-year-old female patient visited our clinic for diplopia and ocular motility disorder after removal of an epidermoid tumor of the brain. At her initial visit, her best-corrected visual acuity (BCVA) was 20/20 for both eyes. An alternate cover test showed 45 prism-diopter esotropia and 3 prism-diopter hypertropia in the right eye. Following 6 months of observation, the deviation of the strabismus did not improve, and botulinum toxin was injected into the right medial rectus (RMR). After 6 days, she visited our clinic with decreased visual acuity of her right eye. The BCVA was found to be 20/50 for her right eye. Funduscopic examination presented a retinal tear inferonasal to the optic disc with preretinal hemorrhage. Subretinal fluid nasal to the fovea was seen on optical coherence tomography (OCT). Barrier laser photocoagulation was done around the retinal tear; however, her visual acuity continued to decrease, and vitreous hemorrhage and subretinal fluid at the lesion did not improve. In addition, a newly developed epiretinal membrane was seen on OCT. An alternate cover test presented 30 prism-diopter right esotropia. 19 weeks after RMR botulinum toxin injection, she received pars plana vitrectomy, membranectomy, endolaser barrier photocoagulation, and intravitreal bevacizumab (Avastin®) injection. After 4 months, her visual acuity improved to 20/20, and only 4 prism-diopter of right hypertropia and 3 prism-diopter of exotropia were noted. Vitreous opacity and the epiretinal membrane were completely removed, as confirmed by funduscopic and examination.

Conclusions

Sudden loss of vision after injection of botulinum toxin into the extraocular muscle may suggest a serious complication, and a prompt, thorough ophthalmic examination should be performed. If improvements are not observed, rapid surgical intervention is recommended to prevent additional complications.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0649-2) contains supplementary material, which is available to authorized users.