Too Much or Too Little?: A Systematic Review of Post-Paretic Synkinesis Treatment
Jodi B Lapidus, MPHS; Johnny Chuieng-Yi Lu, MD; Katherine Bernadette Santosa, MD, MS; Alison K. Snyder-Warwick, MD
Washington University School of Medicine, St. Louis, MO
Introduction: Facial synkinesis is a potentially life-altering sequela of facial nerve injury. Abnormal involuntary movements can have a detrimental impact on function and quality of life. Despite the necessity of effective treatment, there is significant controversy among clinicians about the optimal treatment modality, characteristics of therapy, and how to report treatment outcomes. The goals of this study were to comprehensively summarize and evaluate the quality of the current synkinesis literature, and to compare the effectiveness of common synkinesis treatment modalities.
Materials & Methods: A medical librarian performed a literature search of Embase, Ovid Medline, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and clinicaltrials.gov using relevant concept terms in February 2018. Full-text English language articles describing cohort studies or randomized controlled trials regarding treatment of synkinesis were eligible for inclusion. Reviews, comments, animal studies, and those without quantitative measurement of treatment effect were excluded. Two authors independently reviewed eligible articles, extracted data, and appraised quality.
Results: The literature search returned a total of 582 unique citations; 30 articles were included in the final analyses. Eight studies focused on botulinum toxin (BTX-A), 6 on surgery, 5 on physical therapy, and 11 on multimodal therapy. Overall, 898 patients across studies were included. The Sunnybrook Facial Grading System was the most frequently used outcome measure (17 studies, 56.7%). The mean percentage change in synkinesis was 13.65% [-11.8 to 19.6%] for BTX-A treatment, 14.6% [0 to 41.2%] for physical therapy, 6.6% [0 to 41%] for surgery, and 12.5% [0 to 36%] for therapy combining two or more modalities. Only 19 studies (63.3%) provided data on adverse outcomes. According to the Newcastle-Ottawa Scale conversion to AHRQ standards, 2 studies (6.7%) were of good quality, and 28 were of poor quality (93.3%).
Conclusions: Currently, there is no gold standard treatment or outcome reporting measure for facial synkinesis. Our results suggest that this complex clinical challenge is likely best tackled non-surgically or through multimodal treatment. Despite the sufficient availability of studies, the level of scientific rigor demonstrated in the current literature does not allow adequate comparisons of effectiveness. Adoption of standardized patient evaluation and outcome reporting methods are necessary for robust comparative effectiveness studies in this area.
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