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A Cadaveric Study of Dye Spreading: Determining the Ideal Injection Pattern for Masseter Hypertrophy
Author(s)
Sermswan, Peerada
Tansatit, Tanvaa
Meevassana, Jiraroch
Panchaprateep, Ratchathorn
Date Issued
October 1, 2021
Type
Article
Abstract
BACKGROUNDMasseter hypertrophy is the main cause of an asymmetrical and squared lower facial contour in the Asian community. Botulinum toxin injection technique is crucial to treat this condition.OBJECTIVETo improve injection techniques for masseter hypertrophy by elucidating the distribution of the injections within the masseter.METHODSThirty masseter muscles were divided into 6 groups of 5 muscles each. Each group received one 0.2- or 0.3-mL injection at Point A, B, or C according to a three-point technique. Muscle dimensions and dye of the primary and secondary dye spreading were measured.RESULTSThe average muscle length, width, and thickness were 69.87, 33.50, and 11.23 mm, respectively. The average primary longitudinal and horizontal spreading was 36.56 and 15.60 mm, respectively. No statistically significant difference was found between 0.2- and 0.3-mL injections at each point.CONCLUSIONThe three-point technique best fits in the safe zone and should be the standard injection technique for masseter hypertrophy. Injection at Points B and C may create secondary spreading that affect the risorius muscle and the parotid gland which are the cause of asymmetrical smiling and xerostomia, respectively. The dosage should be adjusted according to the muscle volume and not only the thickness.
Citation
Dermatologic Surgery, 47(10), 1354-1358, 2021