RimabotulinumtoxinB versus OnabotulinumtoxinA in the Treatment of Masseter Hypertrophy: A 24-Week Double-Blind Randomized Split-Face Study

Abstract

Background: Masseter hypertrophy can be ameliorated by botulinum toxin. Objective: To compare the efficacy and safety of RimabotulinumtoxinB (BTX-B) and OnabotulinumtoxinA (BTX-A) in the treatment of masseter hypertrophy. Methods: Sixteen women with bilateral masseter hypertrophy received single injections of BTX-A or BTX-B at a dose ratio of 1:50 or 1:70 in a 24-week double-blind randomized split-face study. Results: Both BTX-A and BTX-B produced significant improvements in masseter hypertrophy. The maximum volume reduction, as determined by computed tomography scanning, at week 12 was comparable between BTX-A and BTX-B at a dose ratio of 1:70 (15.6 and 14.2%, respectively). At week 24, only masseters treated with BTX-A maintained a significant volume reduction. Investigator ratings and patient satisfaction scores paralleled objective computed tomography measurements. Conclusion: Both BTX-A and BTX-B are effective in the treatment of masseter hypertrophy. BTX-B, at a dose ratio of 1:70, has a comparable efficacy but a shorter duration of action than BTX-A.

Literature review of the adverse events associated with botulinum toxin injection for the masseter muscle hypertrophy

“…In addition, one study compared Ona‐A and Abo‐A, while another split face study compared Ona‐A and Inco‐A. Of studies using BoNT‐B, 1 split face study from 2013 compared the effects between Rima‐B and Ona‐A—the 2 serotypes were found to be of similar efficacy, but Ona‐A produced a longer‐lasting result. In addition, there were 5 articles that did not indicate the serotype or subtype of BoNT used.…”

“…BoNT-A can be further separated into multiple subtypes based on individual commercial formulations such as molecular weight or presence of complexing proteins. 31 -the 2 serotypes were found to be of similar efficacy, but Ona-A produced a longer-lasting result. In addition, there were 5 articles that did not indicate the serotype or subtype of BoNT used.…”

Statistical reporting in randomized controlled trials from the dermatology literature: a review of 44 dermatology journals

“…After manuscript review, two were excluded for being duplicates and 27 were excluded for not being RCTs. This left 181 articles in 27 journals to be included in the review . Of these, 137 studies had parallel‐armed control groups, 42 had placebo control groups, one was a cross‐over design and one used no treatment as the control group.…”

Considerations for the Use of Minimally Invasive Aesthetic Procedures for Facial Remodeling in Transgender Individuals

“…Full-face transition in a 25-year-old male-to-female transgender patient (Figure 3). This patient, who had been on estrogen therapy for over 2 years, received 4 units of onabotulinumtoxinA at each lateral end of her eyebrows Inject into forehead, glabellar, or periorbital areas to eliminate dynamic rhytids and create a more feminine forehead, angled eyebrow shape, and widened eyes; 5,9 injection into the superolateral orbital portion of the orbicularis oculi muscle may raise the lateral brow, 44,45 whereas injection into the palpebral portion of the orbicularis oculi may widen the eye aperture, with injections placed inferior to the lower eyelid and lateral to the midpupillary line 43 Inject along zygomatic arch to help cheeks appear more prominent and contoured; inject into anterior malar area to create a prominent, full, and more feminine apex peaking more superiorly and laterally 5,9 Atrophy the glabellar musculature to help create a more obtuse nasofrontal angle; 5 weaken the depressor septi nasi muscle to feminize the nose by lifting the nasal tip; weaken the nasal alar muscles to decrease alar flare Inject medially into chin to give it a more-rounded, less-square contour Inject into the masseter and mentalis muscles to cause gradual atrophy, decreasing the prominence of the male jawline and making the face appear more heart shaped 44,46 Inject into lips to augment them 9 and into the perioral region to improve lip contour and decrease rhytids 47 Address signs of aging such as temple volume loss, marionette hollowing, prejowl sulcus, and tear trough development…”