Units Of Botulinum Toxin Type Research Articles

Reshaping Smiles: A Successful Clinical Case with Botulinum Toxin for Gummy Smile Reduction

The use of botulinum toxin (BTX) represents an effective and safe approach in treating the gummy smile, reducing excessive gum exposure during smiling. This minimally invasive procedure can yield remarkable aesthetic results and contribute to an increase in the patient's self-confidence. The aim of this study is to report a clinical case of a female patient undergoing treatment to correct a gummy smile. The case study involves a 21-year-old patient with excessive gum exposure (5 mm when smiling) who sought dental treatment. The origin of her gummy smile was mixed, and the treatment involved the application of 6 units of BTX type A at three specific points on the face. No complications were observed during the three-month follow-up period. Based on the case report, it can be concluded that BTX application for gummy smile treatment proved to be effective, safe, and comfortable in terms of recovery. The BTX approach to correcting a gummy smile is considered safe and entails straightforward recovery, producing satisfactory results that contribute to the improvement of aesthetics and the patient's well-being.

Technical aspects of performing laparoscopic hernioplasty in the treatment of large ventral hernias

Laparoscopic hernioplasty is a promising treatment option for ventral hernias. The technique of intraperitoneal mesh placement (IPOM) is the most extensively studied and widely used for the closure of a defect during laparoscopic hernia repair. The large size of the defect and its diameter exceeding 10 cm are limiting factors in the selection of minimally invasive techniques for hernioplasty. The process of suturing the hernia prior to the placement of the mesh, as well as the technique used to fix it, show controversial results in terms of postoperative quality of life and the risk of recurrence. Objective — to study the technical aspects of performing laparoscopic prosthetic hernioplasty using the IРOM technique for the surgical treatment of patients with large primary ventral hernias (PVH) and postoperative incisional ventral hernias (IVH). Materials and methods. The study included a total of 84 patients who were undergoing treatment at the clinical base of the Department of General Surgery No. 2 of Bogomolets National Medical University. There were 51 (60.7%) women and 33 (39.3%) men. The average age was 58.73±10.9 years. All patients were operated on for large ventral hernias. Of these, 52 (61.9%) patients had surgery for PVH (umbilical hernia, line alba hernia), while 32 (38.1%) — for IVH. In 56 (66.7) patients, the width of the hernia defect was > 10 cm, of which 24 (28.6%) patients had PVH. In these patients, 4 weeks before surgery, 100 units of botulinum toxin type A (BTA) were injected intramuscularly into the muscles of the anterior abdominal wall in accordance with the methodology developed in the clinic. All patients underwent laparoscopic prosthetic hernioplasty with IPOM under general combined anesthesia. Control examinations of patients were carried out 2 weeks, 1 month, 6 months, and 1 year after the operation. Results. All patients underwent IPOM, while 38 (45.2%) patients underwent laparoscopic IPOM with suturing of the defect, 36 (42.9%) patients underwent IPOM with suturing the hernia defect before placing the mesh (IPOM+), and 10 (11.9%) patients underwent IPOM without suturing the defect. 32 (38.1%) patients were aged 65 years, including 10 patients who did not undergo suturing of the defect before the mesh placement. After the injection of BTA, the number of patients with a defect width of ≥10 cm decreased to 15 (17.8%). All of these patients had a defect smaller than 15 cm. The average duration of surgery for IPOM without hernia suturing was 60.00±11.30 min; for IPOM with laparoscopic suturing, it was 108.16±40.29 min; for IPOM+ with open suturing, it was152.08±40.64 min. The average length of stay in the hospital after surgery was higher in the group of patients who underwent hernioplasty using the IPOM+ technique compared to other techniques (p <0.001). In the early postoperative period, the complication rate was 13.1%; all cases were classified as minor (Grade I, II, IIIa) according to the Clavien–Dindo classification. Conclusions. Laparoscopic hernioplasty using the IPOM is a safe and reliable method for large ventral hernia repair. Administering preoperative BTA injections enables the reduction of the defect and facilitates the execution of laparoscopic hernioplasty in patients with a primary hernia size of ≥10 cm.

Methodology of botulinum therapy in the treatment of dystonic scoliosis in generalized dystonia (clinical case)

Dystonic scoliosis as one of the forms of generalized dystonia is a highly disabling form of dystonia, which can lead to damage to internal organs (lungs, heart) and the peripheral nervous system, including the spinal cord. Almost always, those muscles that are involved in the formation of a dystonic posture in generalized dystonia have not been studied in terms of the effectiveness of treatment with botulinum toxin type A and are not reflected in the instructions. As a result, there is no understanding of the general motor interaction with differentiation into targeted and non-targeted muscles, administration doses and control methods.The aim of the work was to evaluate the efficacy and tolerability of high doses of botulinum toxin type A in dystonic scoliosis, as well as to present the introduction of botulinum toxin type A using ultrasound and electromyographic control. We have described a clinical case of a 19-year-old patient suffering from generalized dystonia with S-shaped dystonic scoliosis of the III degree. Deep brain stimulation was recommended as a treatment for the patient. During the waiting period for the timing of the operation, we attempted symptomatic therapy using the drug incobotulotoxin A. Over the next year and a half, 700 units of botulinum toxin type A were administered under ultrasound and electromyographic control every 3–4 months. As a result, treatment of trunk dystonia in the patient during the observation period led to a clinically significant decrease in the degree of curvature (from 37° to 27°, from III to II degree of scoliosis) in the absence of undesirable effects of the drug, including generalized muscle weakness. According to the repeated conclusion of the council of neurosurgeons, surgical intervention is not indicated for the patient due to the positive effect of the introduction of botulinum toxin type A.

Botulinum Toxin A Delivery via MMP Technique: An Emerging Therapeutic Approach for Frontal Fibrosing Alopecia

Frontal Fibrosing Alopecia (FFA) is a disease of unknown etiology and pathogenesis whose prevalence has been increasing since its first description in 1994. With no cure, treatments only control the inflammatory process and disease progression, but do not reverse the changes induced by it. We report the case of a patient with early-stage FFA who underwent three monthly sessions of 30 units of Botulinum Toxin Type A administered by MMP® (Microinfusion of drugs through the skin) technique. The results showed a substantial improvement in the patient's clinical condition with inhibition of the inflammatory process and an evident increase in follicular density in the treated area.

Comparison studies of ultrasound-guided botulinum toxin injection and balloon catheter dilatation in the treatment of neurogenic cricopharyngeal muscle dysfunction.

Cricopharyngeal muscle dysfunction (CPD) management has been challenging in clinical practice. To compare the efficacy and safety of ultrasound-guided botulinum toxin injection and balloon catheter dilatation in treating CPD. Forty patients with CPD were randomly divided into two groups, namely the botulinum toxin injection group (BTX group) and balloon dilatation group (BD group). Patients in the BTX group received a single ultrasound-guided injection of 50 units of botulinum toxin type A, while the BD group received dilatation therapy five times per week, consecutively for two weeks. Relative opening percentage of the upper esophageal sphincter (UES), the penetration-aspiration scale (PAS), and the Dysphagia Outcome Severity Scale (DOSS) were evaluated by a videofluoroscopic swallowing study (VFSS) at baseline, 1-month, and 3-months posttreatment. The Functional Oral Intake Scale (FOIS) and Standardized Swallowing Assessment (SSA) were also used to evaluate participants' swallowing function at baseline and the 1-week, 2-week, 1-month, and 3-month follow-ups. A generalized estimating equation (GEE) model revealed the significant main effect for time in UES, PAS, DOSS, FOIS, and SSA compared to baseline (P <0.05), while no group-by-time interactions (except for the PAS assessment) or main effect for treatment was detected among the above multiple variances. No systematic complications or severe adverse effects were noted. Both ultrasound-guided botulinum toxin type A injections and balloon dilatation therapy have been proven as safe and effective treatments for CPD patients. Future clinical trials with longer follow-up periods and more participants are warranted.

Correction of overactive bladder with botulinum toxin type A (BTX-A)

One of the most common dysfunction is overactive bladder. The clinical symptoms are associated with an involuntary contraction of the detrusor muscle of the urethra. Drugs are the basis of overactive bladder therapy. However, the duration of drug therapy is limited due to the frequent development of side effects. The study aimed to examine the efficacy of using botulinum toxin type A (BTX-A) in patients with overactive bladder. A total of 90 patients with overactive bladder (mean age 39.86 ± 3.47 years; 59 (65.6%) women and 31 (34.4%) men) divided into two groups (45 patients each) were examined: Group 1 included patients without imperative urinary incontinence, and Group 2 included patients with imperative urinary incontinence. Patients in both groups underwent intravesical injection of 200 units of botulinum toxin type A (Xeomin). The BTX- A for treating patients with overactive bladder reduces clinical symptoms, increases the functional volume of the bladder, and facilitates an improvement in the life quality of patients. The use of BTX-A in patients suffering from overactive bladder and not responding to drug therapy with m-cholinolytics is effective and safe, which allows recommending this treatment method to correct the studied bladder dysfunction in such patients.

Orthostatic Jaw Tremor, a Diagnostic Challenge for Neurologists

Jaw tremor is usually associated with tremor or other abnormal involuntary movements affecting additional body parts, but isolated jaw tremor is a rare clinical presentation. A 40-year-old man presented with history of paroxysmal jaw tremor for 3 years with no other neurological symptoms, psychiatric conditions, or a family history of neurological disorders. The tremor occurred only in the resting jaw position, with 10 episodes per day on an average, and lasted from 10 minutes to hours. It disappeared with any voluntary activation of the masseter muscle and did not change (in amplitude or frequency) with distraction maneuvers. The remainder of neurologic examination was unremarkable. The patient underwent extensive testing, including contrast-enhanced brain magnetic resonance imaging, blood tests and neuropsychiatric evaluation by two different neuropsychiatrists which failed to reveal the underlying cause. The needle electromyography examination revealed involuntary, intermittent, and synchronized muscular contractions in both masseter muscles, at a frequency of 13 to 14 Hz. No changes were discovered in the other muscles. He was treated with propranolol, primidone, valproic acid, diazepam, and amitriptyline, but the response was not significant. Injection of 25 units of botulinum toxin type A in the masseter muscle on both sides of the fac was effective five days after the injection. No adverse effects or masseter weakness were observed.

Real-world migraine burden: clinical and economic aspects

To evaluate the rationale for different approaches to preventive chronic migraine (CM) treatment by comparing clinical outcomes and financial burden of the disease in the real-world practice. Sixty-six patients with CM were enrolled at the Alexander Vein Headache Clinic (60 women and 6 men, aged 28-51). All patients were divided into 3 groups: group 1 (n=22) received oral preventative treatment with topiramate, up to 100 mg daily, for three months; group 2 (n=20) received 12 acupuncture sessions (3 sessions a week); group 3 (n=24) received 155-195 units of botulinum toxin type A (botox, BTA). The follow-up period in all groups was 3 months. Efficacy was evaluated by clinical examination, the Headache Impact Test (HIT-6) and questionnaires to assess subjective patient satisfaction and treatment tolerability. BTA demonstrated the highest efficacy in this study. Compared to the oral preventative treatment and acupuncture, BTA reduced the frequency of headache faster and more significantly facilitating CM transformation into episodic migraine (headache frequency was 16.1±0.1; 18.0±0.02; and 13.9±0.3 in groups 1, 2 and 3, respectively, after one month of treatment). BTA also improved the quality of life faster and more significantly and was better tolerated (good - 51%, 75% and 85% in groups 1, 2 and 3, respectively; satisfactory - 35%, 25% and 15% in groups 1, 2 and 3, respectively; bad 14% in the oral prevention group). In the BTA group, the majority of patients demonstrated earlier treatment satisfaction. Despite higher (compared to topiramate) direct costs in the BTA group (RUB 29 931.51 and RUB 32 085.87, respectively), the predicted cost of a headache-free day was the smallest and totaled RUB 652.15 (compared to RUB 692.86 and RUB 1017.60 in the topiramate and acupuncture groups, respectively). The data on the efficacy and costs of different CM prevention strategies would facilitate optimal treatment choice for neurologists and patients.

An objective method to assess the improvements of skin texture roughness after botulinum toxin type a treatment of crow's feet.

Photo-numeric scales could lack precision and objectivity on evaluating the improvements on wrinkles after a treatment with botulinum toxin type A. The authors suggest a new digital evaluation method to analyze its effectiveness. This study aims to investigate retrospectively the effect of intramuscular injection of botulinum toxin type A on skin texture in the lateral peri-orbital region with a new objective method. Skin texture roughness (STR) in the lateral peri-orbital region is evaluated with a multi-directional light beam by light emitting diodes of different wavelengths (Antera 3D® ), before and after injections of 12 units of botulinum toxin type A. The wrinkles and lines deeper than 0.5mm are filtered to measure accurately skin texture. We observed an improvement of STR in all cases treated with botulinum toxin type A. A significant decrease of STR was recorded as follows: 17.08% (P<.0001) at 4weeks and 12.14% at 4months (P=.001). Botulinum toxin type A treatment of crow's feet was able to improve STR. The Antera® device and software are a valuable, objective, easy and reproducible method to assess the effects of the toxin.

The Effect of Botulinum Toxin on the Amount of Sialorrhea in Patients With Neurologic Diseases

Background: Drooling is an annoying problem in some neurologic and systemic diseases. Injecting botulinum toxin in the salivary glands is one of the most effective and safest treatments. Objectives: This study was conducted to evaluate the effect of botulinum toxin on the amount of sialorrhea in patients with neurologic diseases. Materials and methods: This study included ten patients and 60 units of botulinum toxin type A (Dysport) were injected in any submandibular gland and 120 units were injected in any parotid gland bilaterally under the ultrasonographic guide. To check drooling, daily consumption of tissue was counted and it was cheeked once before injection and at six, 12, 18, and 24 weeks after injection; then the results were compared. Results: In this study, the effect of Dysport on the amount of drooling of the participants at the sixth, 12th, and 18th weeks after treatment was significantly decreased (P value of 0.00016, 0.0001, and 0.00011, respectively). However, after 24 weeks, this difference was not significant (P value = 0.15). Conclusions: These finding showed that Dysport can be significantly effective in reducing the amount of saliva for 18 weeks.

Botulinum toxin type A: implications in wound healing, facial cutaneous scarring, and cleft lip repair

Botulinum toxin is a neurotoxin that has been utilized to induce chemo-denervation of muscles. Cutaneous wounds represent a special situation in which the tensile forces applied by these muscles on wound edges might have deleterious effects on the healing process. The aim of this review was to investigate such an effect and to review other mechanisms this toxin might have on the healing process. We also reviewed the role of botulinum toxin in the management of hypertrophic scars and cleft lip repair.

Study of crotoxin on the induction of paralysis in extraocular muscle in animal model

Crotoxin is the major toxin of the venom of the South American rattlesnake Crotalus durissus terrificus, capable of causing a blockade of the neurotransmitters at the neuromuscular junction. The objective of this study was to appraise the action and effectiveness of the crotoxin induced paralysis of the extraocular muscle and to compare its effects with the botulinum toxin type A (BT-A). The crotoxin, with LD50 of 1.5 µg, was injected into the superior rectus muscle in ten New Zealand rabbits. The concentration variance was 0.015 up to 150 µg. Two rabbits received 2 units of botulinum toxin type A for comparative analysis. The evaluation of the paralysis was performed using serial electromyography. After the functional recovery of the muscles, which occurred after two months, six rabbits were sacrificed for anatomopathology study. The animals did not show any evidence of systemic toxicity. Transitory ptosis was observed in almost every animal and remained up to fourteen days. These toxins caused immediate blockade of the electrical potentials. The recovery was gradual in the average of one month with regeneration signs evident on the electromyography. The paralysis effect of the crotoxin on the muscle was proportional to its concentration. The changes with 1.5 µg crotoxin were similar to those produced by the botulinum toxin type A. The histopathology findings were localized to the site of the injection. No signs of muscle fiber's necrosis were seen in any sample. The alterations induced by crotoxin were also proportional to the concentration and similar to botulinum toxin type A in concentration of 1.5 µg. Crotoxin was able to induce transitory paralysis of the superior rectus muscle. This effect was characterized by reduction of action potentials and non-specific signs of fibrillation. Crotoxin, in concentration of 1.5 µg was able to induce similar effects as botulinum toxin type A.

Botulinum Toxin in Neurogenic Detrusor Overactivity

PurposeTo evaluate the effects of botulinum toxin on urodynamic parameters and quality of life in patients with neurogenic detrusor overactivity.MethodsThirty four adult patients with spinal cord injury and detrusor overactivity were selected. The patients received 300 units of botulinum toxin type A. The endpoints evaluated with the episodes of urinary incontinence and measured the maximum cystometric capacity, maximum amplitude of detrusor pressure and bladder compliance at the beginning and end of the study (24 weeks) and evaluated the quality of life by applying the Qualiveen questionnaire.ResultsA significant decrease in the episodes of urinary incontinence was observed. All urodynamic parameters presented a significant improvement. The same was observed in the quality of life index and the specific impact of urinary problems scores from the Qualiveen questionnaire. Six patients did not complete the study, two due to incomplete follow-up, and four violated protocol and were excluded from the analyses. No systemic adverse events of botulinum toxin type A were reported.ConclusionsA botulinum toxin type A showed a significantly improved response in urodynamics parameters and specific and general quality of life.

Thirty-five units of botulinum toxin type A for treatment of axillary hyperhidrosis in female patients

We present a retrospective audit on efficacy and impact of 35 units of botulinum toxin type A per axilla on quality of life in female patients with axillary hyperhidrosis. This audit shows that 35 units of botulinum toxin type A is a reasonable starting dose and could significantly improve patients' quality of life and reduce the cost of treatment.

Abobotulinum Toxin A (Dysport) and Botulinum Toxin Type A (Botox) for Purposeful Induction of Eyelid Ptosis

Chemodervation with abobotulinum toxin A (Dysport) and botulinum toxin type A (Botox) is finding an expanding role in functional and cosmetic cases. We describe the use of chemodenervation with abobotulinum toxin A for functional corneal protection in two cases and botulinum toxin type A for facial symmetry after Bell's palsy in one patient. The first case is a 75-year-old female with a nonhealing corneal erosion in her right eye secondary to epithelial basement membrane corneal dystrophy who underwent injection of 24 units of abobotulinum toxin A to the right Muller's muscle and levator palpebrae superioris to induce a protective ptosis. The second case is a 40-year-old male with corneal decompensation in the right eye after penetrating keratoplasty who underwent similar injection at both sites. The third case is a 46-year-old Asian female with history of Bell's palsty affecting her right side and causing mild left eyelid retraction who was injected 3 units of botulinum toxin type A to her Muller's muscle for lid positioning. Chemodenervation is used in these cases to purposefully induce ptosis by careful injection to Muller's muscle and the levator palpebrae superioris for functional and cosmetic purposes.

Injection of botulinum toxin type A (BOTOX) into trigger zone of trigeminal neuralgia as a means to control pain

This article illustrates a case of persistent trigeminal neuralgia in a medically compromised 65-year-old female who did not respond to pharmacotherapy. She had undergone several peripheral neurectomies as well as a failed right posterior fossa exploration that resulted in a cerebrospinal fluid leak. Persistent pain over the right external nasal area and right mental region was relieved for several hours after daily injections of bupivacaine. A trial of a single dose of 100 units of botulinum toxin type A (BOTOX) diluted in 2.5 mL saline was injected into the external nasal trigger zone (60 units) and to the mental nerve region (40 units). She achieved complete pain relief in the external nasal region for 5 months. Pain recurred and the site was again injected with 100 units of botulinum toxin type A (BOTOX). Pain relief at the mental region was partial. This was finally controlled with peripheral neurectomy. The patient was pain free with a maintenance dose of 200 mg carbamazepine daily for about 1 year, after which she elected to undergo stereotactic gamma knife radiosurgery when pain recurred at the external nasal region.

Constraint-induced movement therapy after injection of Botulinum toxin improves spasticity and motor function in chronic stroke patients

Does injection of Botulinum toxin followed by constraint-induced movement therapy improve spasticity and upper limb motor function more than the same injection followed by rehabilitation based on neurodevelopmental techniques? Randomised trial with concealed allocation and blinded outcome assessment. Rehabilitation department of a tertiary hospital in Taiwan. Adults at least one year after a stroke with a Modified Ashworth Scale (MAS) score of 3 or more in the elbow, wrist, or finger flexors, and with at least 10 degrees of active interphalangeal and metacarpophalangeal extension and 20 degrees of wrist extension. Fixed contractures, major co-morbidities, and previous Botulinum toxin injection or surgery for spasticity were exclusion criteria. Randomisation of 32 participants allotted 16 to each group. Both groups received a total dose of 1000 units of Botulinum toxin type A, injected at standard muscular sites in the affected upper limb, and commenced their 3-month rehabilitation regimen the following day. The intervention group underwent intensive training of the affected upper limb for 2 hours, 3 times per week, while the non-affected upper limb was restrained for at least 5 hours per day. Selected tasks were progressed in complexity, with some assistance with movements and verbal feedback and encouragement. The control group received 1 hour each of physiotherapy and occupational therapy, 3 times per week. Therapy was based on neurodevelopmental techniques, focusing on normalising tone, and movement patterns. The primary outcome was the MAS (0 = no spasticity, 4 = rigid in flexion or extension). Secondary outcomes included the Motor Activity Log (MAL), comprising two 6-point scales of amount of use and quality of movement, and the Action Research Arm Test (ARAT), which rates 19 tasks from 0 (no movement possible) to 3 (normal movement), to give a total score out of 57. 29 participants completed the study. At 6 months, the treatment group had significantly greater reduction in MAS scores for the elbow (0.7, 95% CI 0.1 to 1.3), wrist (0.7, 95% CI 0.2 to 1.2), and fingers (1.2, 95% CI 0.9 to 1.5). Also at 6 months, the treatment group had significantly greater improvement in amount of use (1.1, 95% CI 0.8 to 1.4), quality of movement (0.9, 95% CI 0.6 to 1.2), and ARAT scores (7, 95% CI 4 to 10). Injection of Botulinum toxin followed by constraint-induced movement therapy improves spasticity and upper limb motor function more than the same injection followed by rehabilitation based on neurodevelopmental techniques.

The Change of Maximum Bite Force after Botulinum Toxin Type A Injection for Treating Masseteric Hypertrophy

A botulinum toxin type A injection into the masseter muscle has been used as a noninvasive treatment for masseteric hypertrophy. However, muscle atrophy inevitably causes a change of bite force. The aim of this study was to evaluate the change in the maximum bite force after a botulinum toxin type injection for the treatment of masseteric hypertrophy. Seven patients who had presented for treatment of masseteric hypertrophy participated in this study. Twenty-five units of botulinum toxin type was injected into each masseter muscle, 50 units in total, at two to five points at the prominent portions of the mandibular angle. The bite-force measurement apparatus included a digital multimeter and a bite-force transducer. The maximum bite force between the maxillary and mandibular first molars was measured before injection and at 2, 4, 8, and 12 weeks after injection. The difference in maximum bite force between the preinjection and 2-, 4-, and 8-week postinjection time points was statistically significant. However, there was no such difference between the preinjection and 12-week postinjection values (p < 0.05). The maximum bite force was significantly reduced after injection of botulinum toxin type A for the treatment of masseteric hypertrophy. However, it gradually recovered by 12 weeks.

Patient-Reported Benefit and Satisfaction with Botulinum Toxin Type A Treatment of Moderate to Severe Glabellar Rhytides: Results from a Prospective Open-Label Study

Patient satisfaction is a key measure of success when using botulinum toxin type A to treat glabellar rhytides. However, lack of a standardized method of assessing satisfaction has limited its evaluation. In this open-label study, 58 women with moderate or severe glabellar rhytides at maximum frown were treated with 20 units of botulinum toxin type A (divided injections in corrugator and procerus muscles). Patients' self-perceptions were assessed at baseline and the following were assessed at days 30 and 120: investigator- and patient-rated global assessment of change in glabellar line severity, patient self-perception of age, and patient satisfaction with the effects of treatment and the procedure itself (using the Facial Lines Treatment Satisfaction Questionnaire). Overall, patients had a positive self-image at baseline. At day 30, the investigator reported that all patients had 50 percent or greater improvement in glabellar line severity. At days 30 and 120, 95 percent and 86 percent of patients, respectively, reported satisfaction with treatment overall and 82 percent or more reported satisfaction with various aspects of the effects of treatment (time to onset of action, improvement in facial lines and appearance, and appearing better and relaxed) and the procedure itself (absence of downtime and side effects). More than one-third of patients considered that they looked younger than they did before treatment (by a median of 5 years at both time points). Botulinum toxin type A treatment of glabellar rhytides resulted in high levels of patient satisfaction, and more than one-third of patients thought they appeared younger than they did before treatment.

Effects of Two Different Units of Botulinum Toxin Type A Evaluated by Computed Tomography and Electromyographic Measurements of Human Masseter Muscle

Masseteric hypertrophy is recognized as an asymptomatic enlargement of one or both masseter muscles. Botulinum toxin type A injection into the masseter muscle can be alternatively used as a noninvasive treatment for masseteric hypertrophy. The aim of this study was to evaluate the effects of two different quantities of botulinum toxin type A on the thickness and cross-sectional area and electromyographic changes in the masseter muscle using computed tomography and electromyographic measurement. Thirty-two Korean subjects were enrolled in this study. Twenty-five units of botulinum toxin type A was injected bilaterally in the masseter muscle of 16 subjects, and 35 U was injected bilaterally in the remaining 16. The thickness and cross-sectional area of the masseter muscle were measured at three positions before and 12 weeks after injection using computed tomography. The electromyographic changes in the masseter muscle during maximum voluntary clenching were also evaluated before and 2, 4, 12, and 24 weeks after injection. The difference in the results was statistically analyzed. Statistically significant differences before and after injection were observed when the dimensions and electromyographic values of the masseter muscle were evaluated. However, there was no significant difference between the 25-U and 35-U injections of botulinum toxin type A. The least reduction of muscle thickness was found at the site farthest from the injection point. Several mild side effects were reported, all of which were temporary and localized. Botulinum toxin type A is effective in treating hypertrophy of the masseter muscle, but the dose of the toxin is not associated with its effectiveness within the limits of this study.