Facial surface electromyography: A systematic review on the state of the art and current perspectives.

PURPOSE: Peripheral facial nerve palsy is a severely disabling condition. In current clinical practice, the commonest tools to assess facial palsy are grading scales, digital face image analyses or facial muscle electrophysiology. However, these techniques suffer from subjectivity or invasiveness and cannot be applied as part of a routine clinical assessment. Therefore, novel non-invasive office-based tools are needed. Surface electromyography (sEMG) may potentially fulfill the requirements of objectivity, low examiner-dependence, and minimal invasiveness. The aim of this systematic review is to define the state of the art on the use of sEMG for facial nerve functional assessment. MATERIALS AND METHODS: Pubmed, Scopus and Web of Science databases were systematically searched. The study protocol was registered on PROSPERO in January 2023. The review was conducted according to the PRISMA guidelines. RESULTS: After the application of inclusion-exclusion criteria, 15 manuscripts with adequate relevance to this topic were included in the review. CONCLUSIONS: Facial sEMG represents a potentially useful tool to implement objective quantification of facial nerve function in clinical practice. Given the heterogeneity of methods and analysis in the available studies, sEMG results are hardly comparable. The introduction of methodological guidelines, followed by large prospective studies on well-defined subsets of patients with facial nerve impairment, is advocated.

Facial Surface Electromyography: A Novel Approach to Facial Nerve Functional Evaluation after Vestibular Schwannoma Surgery.

BACKGROUND: Vestibular schwannoma (VS) surgery may cause facial nerve damage. However, a comprehensive evaluation of post-operative facial outcomes may be difficult to achieve. Surface electromyography (sEMG) is a promising non-invasive evaluation tool. However, its use in the follow-up after VS surgery has not been reported yet. The main objective was to develop and validate a new sEMG application specifically for the post-VS surgery setting. Secondary goals were to provide a systematic description of facial muscle activity after VS surgery and assess the association between sEMG parameters and Sunnybrook scale scores. METHODS: Thirty-three patients with facial palsy following VS surgery were included. The clinical outcomes (Sunnybrook symmetry, movement, and synkinesis scores) and sEMG parameters (signal amplitude normalized by the maximal voluntary contraction (NEMG) and sEMG synkinesis score (ESS, number of synkinesis per movement sequence)) were evaluated at the end of the follow-up. RESULTS: In all tested muscles, NEMG variance was significantly higher on the affected side than the contralateral (variance ratio test, p < 0.00001 for each muscle). In total, 30 out of 33 patients (90.9%) showed an ESS ≥ 1 (median: 2.5, IQR: 1.5-3.0). On the affected side, NEMG values positively correlated with both dynamic and overall Sunnybrook scores (Spearman's model, p < 0.05 for each muscle, except orbicularis oculi). ESS significantly correlated with the Sunnybrook synkinesis score (Spearman's rho: 0.8268, p < 0.0001). CONCLUSIONS: We described and preliminarily validated a novel multiparametric sEMG approach based on both signal amplitude and synkinesis evaluation specifically for oto-neurosurgery. Large-scale studies are mandatory to further characterize the semiological and prognostic value of facial sEMG.

A Pathophysiological Approach to Spontaneous Orbital Meningoceles: Case Report and Systematic Review.

BACKGROUND: Spontaneous orbital cephaloceles are a rare condition. The purpose of this study is to provide a description of a clinical case and to carry out a systematic literature review. METHODS: A systematic review of the English literature published on the Pubmed, Scopus, and Web of Science databases was conducted, according to the PRISMA recommendations. RESULTS: A 6-year-old patient was admitted for right otomastoiditis and thrombosis of the sigmoid and transverse sinuses, as well as the proximal portion of the internal jugular vein. Radiological examinations revealed a left orbital mass (22 × 14 mm) compatible with asymptomatic orbital meningocele (MC) herniated from the superior orbital fissure (SOF). The child underwent a right mastoidectomy. After the development of symptoms and signs of intracranial hypertension (ICH), endovascular thrombectomy and transverse sinus stenting were performed, with improvement of the clinical conditions and reduction of the orbital MC. The systematic literature review encompassed 29 publications on 43 patients with spontaneous orbital MC. In the majority of cases, surgery was the preferred treatment. CONCLUSIONS: The present case report and systematic review highlight the importance of ICH investigation and a pathophysiological-oriented treatment approach. The experiences described in the literature are limited, making the collection of additional data paramount.