BOTULINUM TOXIN TYPE A, NON-INVASIVE TREATMENT FOR MASSETER MUSCLE HYPERTROPHY, MODE OF INJECTION OF BOTOX

1. Botulinum Toxin Type A in the Management of
Masseter Muscle Hypertrophy
Dr. VIJAYA LAKSHMI G
II MDS, Dept. of OMFS

2. Wagner Henriques Castro, DDS, MS,
Rodrigo Santiago Gomez, MD,
Jacqueline da Silva Oliveira, DDS,
Mariela Dutra Gontijo Moura, DDS,
Ricardo Santiago Gomez, DDS, PhD
2005

3. CONTENTS
• Introduction
• Patients and methods
• Results
• Discussion
• Critical evaluation
• References

4. INTRODUCTION
Masseteric muscle hypertrophy (MMH) is a relatively uncommon condition that may present as either a
unilateral or bilateral painless swelling in the region of the angle of the mandible.
Etiology of this anomaly is still unexplained.
Diagnosis is usually established clinically; conventional radiography, CT, MRI and USG may be helpful.
Treatment usually involves resection of a portion of the masseter muscle and/or the removal of exostoses of the
mandibular angle that are frequently associated with this condition.

5. Botulinum toxin type A (BtA) is a potent bacterial neurotoxin produced by anaerobic bacterium
Clostridium botulinum that produces muscle paralysis, atrophy, and weakness.
It has been largely used in medicine in the treatment of alterations characterized by involuntary
spasm of certain muscles, and more recently for cosmetic treatment of hyperfunctional lines.

6. The use of BtA has been reported as a successful method of treatment of MMH that offers some
advantages over conventional surgical treatment.
Report on the treatment of 6 patients with unilateral or bilateral MMH with the use of
intramuscular injections of BtA.

7. PATIENTS AND METHODS
6 patients with unilateral or bilateral MMH were selected by confirming the diagnosis through physical and
radiographic examination-OPG of all patients for hyperostosis diagnosis.
BtA injections were selected as the treatment method, and none of the patients had already received this
form of treatment.

8. The drug used for injections was C. botulinum type A toxin (Dysport; Speywood Pharmaceuticals Ltd,
Berkshire, England, or Botox; Allergan Inc, Irvine,CA).
Composition of Dysport vial-
500 units of BtA dissolved in 2.5 mL of normal saline solution
Final concentration of 200 units/ml.
Composition of Botox vial-
100 units of BtA dissolved in 2.0 Ml of normal saline solution
final concentration of 50 units/ml.

10. Administration-
The point of administration was identified
visually and by palpation with the patient on
clenching.
3.0-mL syringe with 25-gauge needle, the
toxin was administered percutaneously in
varying doses after aspiration, in the thickest
portion of the hypertrophied masseter muscle.
Massaging of the muscle to spread the drug.

11. Recurrence- was considered when the relapse of hypertrophy was noted through clinical and
photographic evaluation of the patient and/or when the patient claimed that muscular discomfort
returned.

12. RESULTS
4
2
Masseter muscle hypertrophy
Bilateral MMH Unilateral MMH
Main complaint of all patients was of an esthetic nature,
5 patients- Mild pain was reported in association with
the hypertrophied muscles.

13. Pre-op Post-op

14. Pre-op Post-op

15. All patients presented with satisfactory regression of MMH, including muscular discomfort and
pain.
Recurrence (relapse of hypertrophy) was observed in 2 cases (patients 1 and 2) but without the
recurrence of symptoms of pain.
Dysport vial Botox vial
2 0

16. DISCUSSION
Complaints of a patient with MMH-
i. Usually esthetic
ii. Mild pain
iii. Heavy sensation in the region of the hypertrophied muscle, and/or
iv. Moderate limitation of mouth opening
5/6 patients had these symptoms, which disappeared after BtA treatment.

17. Although in the majority of MMH cases the etiology is unexplained, it has been attributed to
many causes such as malocclusion, bruxism, clenching, and TMJ disorders.
In 3 of the present patients (patients 4, 5, and 6), the treatment included the control of
parafunctional activities involving the masticatory musculature of patients.
The treatment for parafunctional activity involves the use of an intraoral orthodontic appliance
and neuromuscular re-education exercises to alter the existing muscle function and to help manage
parafunctional habits.

18. BtA is a complex bacterial protein produced by C.botulinum.6 In muscle, it blocks the
neuromuscular transmission through rapid and strong attachment to the presynaptic nerve
membrane, and then it inhibits the release of vesicle-bound acetylcholine at the neuromuscular
junction, producing functional denervation of the muscle and its subsequent atrophy.
Injection of a small amount of this toxin into a muscle produces atrophy and weakness within 1
to 20 days and recovery over 2 to 4 months as new terminal axon sprouts form and restore
transmission. It has been suggested that this new nerve sprout then retracts and the original
junction returns to functionality.

19. Bioequivalence between Botox and Dysport doses of 1:3 for cervical dystonia treatment and 1:4 for
blepharospasm and hemifacial spasm therapy.
Local injections of BtA have been used as a safe and effective method in the treatment of disorders such as
strabismus, nystagmus, spasmodic torticollis, blepharospasm, oromandibular dystonias, tremors, hemifacial
spasms, cricopharyngeal dysphagia, spasmodic dysphonia, rejuvenation, temporomandibular disorders, recurrent
TMJ dislocation, and bruxism and for functional benefit and reduction of disability in cerebral palsy, among other
alterations.
Other applications of Botox-

20. Contraindications-
• History of hypersensitivity to the drug,
• Presence of inflammation at the proposed injection site
• Diseases of neuromuscular transmission and coagulopathy.
• Safety for use during pregnancy or lactation has not been established.
• Coincident administration of agents known to potentiate neuromuscular blockade
(aminoglycosides) should be avoided.
• Single large doses of greater than 500 mouse units of botulinum may produce acute symptoms
and signs of botulism.

21. CONCLUSION
The use of BtA in MMH therapy offers some obvious advantages in relation to conventional
surgical treatment. This approach is non-traumatic and is more cost-effective with few side effects.

23. Frontal view showing mandibular
left angle prominence
Intraoral view showing midline deviation
during occlusion.

24. Anteroposterior radiograph showing spur development
in the left angle of the mandible
CT scan showing hypertrophy of masseter
muscle

25. MRI scan confirming the findings of the
anteroposterior radiograph ,hypertrophy of the
masseter muscle on the left side.

26. Diagnostic technique using ultrasound, the establishment of a normal range by its application to
a control population and its use on patients with clinical masseteric hypertrophy.
Relaxed position- 8.5-13.5mm
Clenched position- 10.5-16.5mm

27. Ultrasound image of normal masseter
Ultrasound image of hypertrophied masseter

28. Botulinum toxin type A (BT) injection into the masseter muscle offers promise as a new and
simple treatment.

29. Facial appearance 4 months after botulinum toxin injection.
Facial appearance of patient at the first visit.
Unilateral left masseteric hypertrophy

30. With a single surgery treatment of bilateral masseteric hypertrophy and mandibular
retrognathism have been carried out which is probably the first of its kind.

31. PRE-OP

32. BSSO ADVANCEMENT 8MM
PRE-OP OPG

33. POST-OP

34. CRITICAL EVALUATION
Pros-
1. Non- invasive technique and offers better results
2. Treatment is performed on an ambulatory basis
3. Treatment is economical when compared to surgery
4. Comparative study was conducted with the same material in varying concentrations, so that minimally
effective concentration of drug can be studied.
5. Recurrence was less along with regression of muscle discomfort and pain.
Cons-
1. Not reviewed enough articles
2. Comparative studies was not being included which compared surgery Vs botox injections
3. Cases were not being divided properly and time interval between each visit is not mentioned.

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38. Thank you…..