Neural mechanisms and neuroplasticity related to deep craniofacial pain

Botulinum toxin: new treatment for temporomandibular disorders

BACKGROUND

Temporomandibular disorders (TMDs) affect the face and jaws, and cause chronic pain and dysfunction in many people. As in other conditions involving the musculoskeletal system, controlling the myogenous component is an integral part of treatment. In this study, we evaluated subjective and objective responses to treatment with botulinum toxin A (BTX-A) in a group of 46 patients with TMDs.

METHODS

46 subjects with TMD were enrolled in this uncontrolled study and treated with BTX-A 150U. Both masseter muscles were injected with 50 U each and both temporalis muscles with 25 U each under electromyographic guidance. Subjects were assessed at two-week intervals for eight weeks. Outcome measures included subjective assessment of pain by visual analogue scale (VAS), measurement of mean maximum voluntary contraction (MVC), interincisal oral opening, tenderness to palpation, and a functional index based on multiple VAS. Medians of the data were taken for each outcome measure at each time point and subjected to Duncan's multiple range test.

RESULTS

There were significant (P<0.05) differences in all median outcome measures between the pre-treatment assessment and the four follow-up assessments except for MVC. Although MVC was significantly reduced midway through the study, it had returned to pretreatment values by the final two assessments. All other outcome measures remained significantly different from the pretreatment findings. Paired correlation of variables including age, sex, diagnosis, depression index, and time of onset showed no significant differences.

CONCLUSIONS

BTX-A injections produced significant improvements in pain, function, mouth opening, and tenderness to palpation. MVC initially diminished then returned to the initial values. Although the study was uncontrolled, the results strongly suggest that BTX-A reduces severity of symptoms and improves functional abilities for patients with TMD and that these extend beyond its muscle-relaxing effects.

Treatment of chronic cervical-associated headache with botulinum toxin A: a pilot study

OBJECTIVE

To see whether therapy with botulinum toxin A may prove to be an effective treatment for headache of musculoskeletal origin.

BACKGROUND

Headache is a common finding associated with neck injury. Cervicogenic headache, which is believed to be attributable to injury of the ligaments, muscles, or joints of the cervical spine, is centered in the occipital region with pain referred to the frontotemporal region. Botulinum toxin A produces prolonged muscle relaxation, which is dose dependent and can be easily targeted to affected muscles.

METHODS

This randomized, double-blind, placebo-controlled study compares outcome measures in 26 patients suffering from chronic headache subsequent to a cervical whiplash injury. One half of the patients received botulinum toxin A, 100 units, diluted in 1 mL of saline, while the other half received just saline (1 mL). Five cervical trigger points received 0.2 mL each of injectant via a 30-gauge needle. Outcome measures included subjective head pain based on visual analog scales, as well as range of neck motion. Follow-up assessments were carried out at 2 and 4 weeks after treatment.

RESULTS

Fourteen subjects who received botulinum toxin A and 12 who received saline completed the study. At both 2 and 4 weeks post injection, the treatment group showed a significant improvement in pain and range of motion from preinjection levels (P<.01). The placebo group demonstrated no statistically significant changes at any posttreatment time.