title: Effectiveness of botulinum toxin (type-A) administered by the fixed-site dosing approach versus the muscle area identification.
abstract: BACKGROUND
  Botulinum toxin is widely used in glabellar musculature. The authors express the need to individualize the approach by means of muscular identification to improve effectiveness. Despite these guidelines, the fixed-point technique is still used.
  
  
  OBJECTIVE
  Comparison of effectiveness of botulinum toxin administration in the glabellar zone by using fixed-site application versus objective-muscle-identification.
  
  
  METHODS
  Prolective dynamic cohort study. Patients (after previous informed consent) were assessed on their facial expressions, level of satisfaction, re-interventions, adverse effects, dosage, dilution, and number of injections. All patients who experienced either of both techniques of botulinum toxin administration (fixed-site or objective-muscle-identification) were subjected to followup by the following parameters: statistical analysis: student's t Test (inter-group mean comparisons), paired student's t test (intra-group mean comparisons), χ (2) with Fisher exact text.
  
  
  RESULTS
  Sixty-two patients were evaluated (31 fixed-site approach, 31 objective-muscle-identification). No patient abandoned the trial during followup. Fixed-site injections required larger doses (16 vs 12 U, p = 0.001), greater volume (0.48 vs. 0.37 ml, p = 0.001), and more application sites (4 vs 2, p = 0.001), compared to the objective-muscle-identification approach. Under the objective-muscle-identification technique, facial expressions were better attenuated (52 vs 65%, p = 0.001), with a higher initial satisfaction level (6 vs 9, p = 0.001) and final satisfaction level (9 vs 9.9, p = 0.001).
  
  
  CONCLUSIONS
  Botulinum toxin application is more effective when administered through the objective-muscle-identification approach (less frowning, lower doses, less fixed sites injected, and patients more satisfied at the end).
  
  
  METHODS
  This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.
authors: Plastic Surgery Division of University of Guadalajara, Medical School, Calzada Federalismo 2022, Guadalajara, Jalisco, Mexico, joseguerrerosantos@hotmail.com.
authors: Jose
authors: J
authors: Guerrrerosantos
authors: Pulido Galaviz
authors: PG
authors: Carlos Eduardo
authors: Josefina
authors: J
authors: Mateos Arriola
authors: Alberto I
authors: AI
authors: Villa Manzano
authors: Benjamin
authors: B
authors: Villarán-Muñoz
authors: Leonel
authors: L
authors: García Benavides
authors: Ma Guadalupe
authors: MG
authors: Vazquez
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D017060:Patient Satisfaction
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A