Effects of botulinum toxin A injection therapy with ultrasound-guided for benign masseter hypertrophy / 中华医学美学美容杂志

Objective:To evaluate the efficacy of botulinum toxin A injection therapy with ultrasound-guided for benign masseter hypertrophy.Methods:Twenty cases (40 sides) of masseter hypertrophy were injected with botulinum toxin A, among which 10 cases were taken as experimental group and the other 10 cases as control group. The experimental group had preoperative ultrasound examination to measure the thickness of masseter, and use ultrasound-guided precise injection during the operation, and then ultrasound recheck to measure the postoperative masseter thickness; The other 10 cases of control group adopt traditional 3-point injection method.Results:The masseter thickness of the two groups at different period of times after treatment was decreased ( P<0.001), the most obviously decrease happened 4-12 weeks after injection. The mean reduction was 26.8% at 4 weeks and 28.4% at 12 weeks after injection. Masseter muscle thickness recovered by 22% at 24 weeks and by 20% at 36 weeks. The average follow-up was 6.0±2.4 months with no serious complications occurred. In the control group, there was a partial masseter bulge in one case. The satisfactory rate of the patients in the experimental group was higher than that of the control group. Conclusions:Botulinum toxin A injection therapy with ultrasound-guided for benign masseter hypertrophy is an effective treatment, which is more accurate and effective than the traditional injection method.

Comparison of clinical efficacy between radiofrequency ablation and botulinum toxin type A in treatment of benign masseter hypertrophy / 中华医学美学美容杂志

Objective To evaluate masseter thickness and its complications of radiofrequency ablation and botulinum toxin type A in the treatment of masseter hypertrophy.Methods Totally 36 patients of benign masseter hypertrophy were randomly divided into radiofrequency ablation therapy group (18 patients) and the injection of botulinum toxin type A treatment group (18 patients).The thickness of the masseter and complications were analyzed before treatment,6 months and 12 months after treatment.Results The average thickness of masseter muscle in botulinum toxin type A and radiofrequency ablation groups was significantly reduced 6 or 12 months after treatment,and the difference was statistically significant (P＜0.05).However,the thickness of masseter muscle in radiofrequency ablation group after 12 months reduced greater than that in botulinum toxin type A group (P＜0.05).Complications of botulinum toxin type A group were swallow difficulty (one patient),unnatural facial expressions (4 patients) and pain at injection site (10 patients) and that in radiofrequency ablation treatment group were that 18 patients had swelling of the skin 1 to 2 weeks after treatment.All patients had recovery 2 weeks after treatment.There was no facial nerve,parotid duct injury,or oral dysfunction.Conclusions The lasting effect of radiofrequency ablation treatment for benign masseter hypertrophy is longer than that of botulinum toxin type A.

Botulinum Toxin Type A for Facial Wrinkles and Benign Masseter Hypertrophy in Korean Patients / 대한피부과학회지

BACKGROUND: The utilization of botulinum toxin has rapidly expanded into various aesthetic applications. Achieving success with the aesthetic use of neurotoxins depends on several factors, including an understanding of the anatomy, the methods of dilution and the injection technique. Any guidelines representing a consensus for aesthetic treatments using botulinum toxin type A (BTA) have not been published in Korea. OBJECTIVE: We wanted to provide consensus recommendations on the treatment of facial wrinkles and benign masseter hypertrophy using BTA in Korean patients. METHODS: A panel of experienced Korean dermatologists was convened to develop a clinical consensus. The clinical consensus was comprised of the recommendations of the panel and the guidelines on general issues, such as the reconstitution and handling of the BTA, the procedural considerations, the dosing and injection-site standardizations, and the prevention and treatment of unwanted effects. Specific recommendations were provided according to the area of treatment, including glabellar lines, horizontal forehead lines, lateral periorbital wrinkles and benign masseter hypertrophy. RESULTS: The recommended final concentration of BTA was 50 units/ml (5 units/0.1 ml) after reconstitution with physiologic saline. For glabellar lines, the members recommend three injection points (a total of 8 units). For forehead wrinkles, the members recommend nine injections in two rows into the frontalis with 1 unit/point. For crow's feet, the members recommend three injections per side (7 units/side) at the lateral part of the orbicularis oculi. For benign masseter hypertrophy, three injections per side (24~30 units/side) were recommended. CONCLUSION: These consensus recommendations will provide a framework for Korean dermatologists who wish to perform safe and efficacious injection of BTA for facial rejuvenation.

The Comparison of Long-term Effect of Botox(R) Injection on Lower Face Contouring after Single Injection and Long-term Repeated Injections by Standardized Photograph Analysis

PURPOSE: A botulinum toxin type A(BoNT-A) injection has been used as a noninvasive management for lower face contouring since 2000. The aim of this study is to compare reduction rate of lower face width for a longtime according to repeated Botox(R) injections on masseter muscles for lower face contouring procedure. METHODS: Forty-five patients were analyzed for single session of Botox(R) injection and 13 patients were evaluated for repeated Botox(R) injections for over two years. Single injection group was tracked regular intervals at 1, 3, 6, 10, 12 months after the injection, and repeated injection group was measured at every injection time. Twenty-five to thirty units of Botox(R) was injected into each masseteric muscle at five to six points at the prominent portions of the mandibular angle. Standardized frontal view of digital photographs were analyzed by Adobe Photoshop(R)(version CS3) to measure an reduction rate of lower face's width. RESULTS: Reduction rate was 3.7%, 6.9%, 6.2%, 4%, 4% at 1, 3, 6, 10, 12 months post injection each other in single injection group. However, more than 8% reduction rate was found in repeated injection group persistently for more than two years. CONCLUSION: This study shows that effective duration of Botox(R) injection for lower face contouring is expected to continue over one year clinically. Moreover, repeated injections maintained lower reduction rate consistently for a long time. Therefore, repeated injections on masseter muscles at regular intervals is the most effective procedure for lower face contouring.

Masseter Muscle Reduction Using Radiofrequency Rhizotomy

Most Korean women prefer ovoid face to squared one and many female patients with squared face want to reduce their lower facial width. Mandibular angle ostectomy and botulinum toxin injection used to be the most common procedures performed to produce this purpose. After botulinum toxin, a series of non-invasive methods to reduce masseter muscle hypertrophy have been introduced. Radiofrequency rhizotomy was first used to treat chronic pain, such as, trigeminal neuralgia and showed good and long-lasting results. This concept of rhizotomy technique was then modified to block motor nerve conduction and used to treat motor dysfunction including painful spasticity. We tried this technique to reduce masseter hypertrophy by blocking the masseteric nerve using radiofrequency. From March 2007 to October 2007, 19 female patients underwent this masseter reduction using radiofrequency rhizotomy and follow-up period was 2 to 6 months. Most results showed reduction of masseter volume with improvement of lower facial contour and no significant complication occurred. The advantages of this method are safety, durability and cost-effectiveness and we think that this technique can be a good alternative method for treating masseter hypertrophy. But, longer follow-up periods and further studies are required to consolidate long-term results.

The Change of the Maximal Bite-force after Botulinum Toxin A Injection for Lower Face Contouring

The temporary effects of muscle atrophy, followed by chemodenervation due to acetylcholine blockade at the neuromuscular junction by botulinum toxin type A(BTX-A) were mainly used for the treatment of hypertrophied muscle. In the treatment of masseter hypertrophy or cosmetic contouring of the lower face with injection of botulinum toxin type A, these muscle atrophy causes the change of the bite-force inevitably. Although several reports about the histological change of muscle, ultrasound and computerized tomography measurement studies of the change of muscle thickness in the treatment of masseter hypertrophy with injection of BTX-A have become available recently, it is necessary to study further the change of the bite-force and the relationship between the bite-force and clinical effects after the botulinum toxin A injection. The aim of this study was to evaluate the change of maximal bite-forces after botulinum toxin type A injections for treating the contouring of the lower face. Botulinum toxin type A(BTXA(R), Lanzhou, China) of 25U per side was carried out in 7 subjects. The change of maximal bite-forces was evaluated at pre-injection and 2 week, 4 week, 8 week, 12 week post-injections using bite- force measuring machine(MPM-3000, Japan). There were statistically significant differences between pre-injection and 2 week, 4 week, 8 week post-injections(p<0.05). However, there was no significant difference between pre-injection and 12 week post-injection. In conclusion, the change of maximal bite-forces after BTX-A injections according to the period was similar to the histological change of the muscle. The clinical effects last more longer than maximal bite force. Therefore, it is necessary to evaluate further these difference with more larger samples and the relationship between the change of maximal bite force and clinical effects.