Buccinator synkinesis treated by botulinum toxin in facial palsy and hemifacial spasms

Approaches to the Management of Synkinesis: A Scoping Review

Postparalysis facial synkinesis (PPFS) can develop in any facial palsy and is associated with significant functional and psychosocial consequences for affected patients. While the prevention of synkinesis especially after Bell's palsy has been well examined, much less evidence exists regarding the management of patients with already established synkinesis. Therefore, the purpose of this review is to summarize the available literature and to provide an overview of the current therapeutic options for facial palsy patients with established synkinesis. A systematic literature review was undertaken, following the Preferred Reporting Items of Systematic Reviews and Meta-analyses 2020 guidelines. MEDLINE via PubMed and Cochrane Library were searched using the following strategy: ([facial palsy] OR [facial paralysis] OR [facial paresis]) AND (synkinesis) AND ([management] OR [guidelines] OR [treatment]). The initial search yielded 201 articles of which 36 original papers and 2 meta-analyses met the criteria for inclusion. Overall, the included articles provided original outcome data on 1,408 patients. Articles were divided into the following treatment categories: chemodenervation (12 studies, 536 patients), facial therapy (5 studies, 206 patients), surgical (10 studies, 389 patients), and combination therapy (9 studies, 278 patients). Results are analyzed and discussed accordingly. Significant heterogeneity in study population and design, lack of control groups, differences in postoperative follow-up, as well as the use of a variety of subjective and objective assessment tools to quantify synkinesis prevent direct comparison between treatment modalities. To date, there is no consensus on how PPFS is best treated. The lack of comparative studies and standardized outcome reporting hinder our understanding of this complex condition. Until higher quality scientific evidence is available, it remains a challenge best approached in an interdisciplinary team. An individualized multimodal therapeutic concept consisting of facial therapy, chemodenervation, and surgery should be tailored to meet the specific needs of the patient.

Botulinum toxin treatment of the buccinator muscle facial synkinesis: A systematic review

BACKGROUND

The purpose of this review is to provide an overview of the available literature assessing the treatment of botulinum toxin injections for the treatment of synkinesis of the buccinator muscle in patients with peripheral facial palsy (PFP).

MATERIALS AND METHODS

A multi database search was performed, including the following databases: Pubmed, Medline, Embase, and the Cochrane Library. Each database was searched from its earliest date until 8 June 2023. The following outcome measures were extracted from the articles when available: subjective, somatic, and psychological effects on the patients and objective outcomes such as the House-Brackmann, Sunnybrook and Sydney scores. The methodological quality of the included studies was rated using the Newcastle-Ottawa scale for nonrandomised trials.

RESULTS

The primary literature search generated 37 articles. After removing duplicates, 25 articles remained for abstract appraisal, of which 20 underwent full-text appraisal, resulting in 3 studies for analysis. All of these studies showed (significant) improvement in synkinesis either measured using the Synkinesis Assessment Questionnaire or subjectively measured by asking treated patients.

CONCLUSION

The available literature supports the finding that botulinum toxin treatment of the buccinator muscle could be a welcome addition to facial synkinesis treatment and could significantly improve patient outcomes. In future studies, the efficacy of EMG-guided buccinator injections, optimal dose, and a validated measuring method could be beneficial in optimising treatment for patients with a PFP and synkinesis.

Chemodenervation of the Posterior Belly of the Digastric Muscle in Facial Synkinesis

Background: Patients with facial synkinesis may have jaw tightness and swallow discomfort despite chemodenervation of facial mimetic musculature, and the posterior belly of the digastric (PBD) muscle is a logical target to treat these symptoms. Learning/Study Objective: To compare patient-reported outcomes of botulinum toxin (BT) chemodenervation of the posterior belly of digastric muscle in patients with postparalytic facial synkinesis. Design Type: Retrospective review. Methods: Patients with facial synkinesis who underwent electromyography (EMG)-guided PBD BT chemodenervation in addition to their baseline therapeutic regimen were included. Pre- and post-treatment Synkinesis Assessment Questionnaires (SAQ) and a two-question survey regarding jaw tightness and swallow discomfort were administered. Results: Twenty-nine patients were included. An average of 5 U of BT-A was injected into the PBD, and 46.5 U across all facial muscles. From pre- to post-injection, patients demonstrated improvement in jaw tightness at rest (3.02 vs. 1.98/5.0, p < 0.001), with swallow (2.78 vs. 1.94/5.0, p < 0.001), and total SAQ (64.3 vs. 51.2/100, p < 0.001). Patients rated subjective benefit from PBD injection compared with prior treatments without PBD injection as 4.5/5.0. Conclusion: Synkinesis patients with jaw tightness or swallow discomfort may benefit from the addition of PBD injections to the therapeutic regimen.

Bibliometric analysis of studies on the treatment of hemifacial spasm

Objective

Hemifacial spasm (HFS) is a common neurological disorder of the brain, which is difficult to treat. Most patients are distracted by it and are unable to work or study normally, which seriously affects their physical and mental health. However, there are a few bibliometric studies on it. This paper searched the articles on HFS using a bibliometric approach.

Method

Articles about HFS were retrieved from the Web of Science (WoS) Core Collection database. We employed the Visualization of Similarities (VOS)viewer to analyze these publications.

Results

A total of 645 reviews or articles in English were retrieved from WoS. In this study, we found that the number of publications showed a rising trend and China is the most active in searching the treatment of HFS. About keywords, neurosciences and neurology was searched (422 times) keyword, followed by hemifacial spasm (420 times) and surgery (320 times). By assessing the organizations, Shanghai Jiao Tong University published the most papers (8.68%), followed by Sungkyunkwan University (3.26%) and Baylor College Medicine (2.64%). A total of 247 journals have delivered publications on the treatment of HFS, World Neurosurgery (44 papers) published the largest number of articles.

Conclusion

The annual publications have increased with a fluctuating tendency. More researchers were taking an interest in HFS. This study helped us find out the hotspot and trend in research about facial spasm treatment.