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Alzheimer's Disease Following Cervical Lymph Node Dissection (CLND): A Decade of Outcomes
Salman Khan
*, Mehdi S. Lemdani, Arturo J. Rios-Diaz, Ashley E. Chang, Ayaka N. Deguchi, Robyn B. Broach, Ivona Percec
University of Pennsylvania, Philadelphia, PA
Background
Standard neurotoxin treatment for glabellar frown lines typically uses a fixed five-point injection technique, despite variability in muscle recruitment patterns among patients. A classification system (U, V, Omega (O), Inverted Omega (IO), Converging Arrows (CA)) describes these variations, but their impact on treatment outcomes has not been quantitatively assessed. This study evaluates how glabellar anatomy influences neurotoxin efficacy using objective 3D strain analysis.
Methods
A total of 142 neurotoxin-naïve women underwent standardized five-point injections. Dynamic strain was quantified via Vectra M3 imaging at baseline and through 180 days. Patients were categorized by an expert injector into glabellar patterns based on muscle recruitment: U (procerus, corrugators), V (plus medial orbicularis), O (orbicularis and frontalis), IO (procerus, corrugators, internal orbicularis, nasalis), and CA (balanced procerus/frontalis).
Results
Significant baseline strain differences existed among patterns (p=0.029), highest in U (16.54%) and lowest in IO (12.01%). All patterns showed strain reduction by day 90, but only U and CA remained significantly improved at 180 days (p<0.05). Peak efficacy occurred at day 30. Patterns U, V, and O retained higher residual strain, while IO showed the lowest absolute strain but smallest reduction (8.37%, p=0.002).
Conclusion
Glabellar contracture patterns significantly affect baseline activity and duration of neurotoxin efficacy. Patterns O and IO exhibit shorter-lived improvements, suggesting customized injection protocols targeting additional muscles (frontalis, orbicularis, nasalis) may enhance patient outcomes.
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