Original ArticleObservation of Effects of Different Surgical Treatments on Unilateral Masticatory Muscle Spasm
Introduction
Masticatory muscle spasm is a disease involving masticatory muscle movement disorders. The main clinical manifestations of this condition include sudden and nonrandom tension contraction of the masticatory muscle resulting in sudden closure of the lower jaw and difficulty in mouth opening and deflection. Persistent sudden spasm can cause trismus, which can affect eating and speaking, and is usually unilateral. Only scattered electromyographic studies1, 2, 3 have been reported worldwide, and there is no generally accepted treatment that is efficacious for the treatment of masticatory muscle spasm. The present literature includes a limited number of reports relating to the treatment of unilateral masticatory spasm by microvascular decompression,4, 5, 6 although these studies involved a small number of cases and lacked patient follow-up data. In the present study, we report the neurosurgical treatment and efficacy of 10 patients suffering unilateral masticatory muscle spasm.
Section snippets
General Information
From February 2010 to September 2016, a total of 10 patients with unilateral masticatory muscle spasm were enrolled, including 2 males and 8 females. Seven of these cases involved the left side, and 3 cases involved the right side. Mean patient age was 45.5 years (range: 37–50 years) with a history of spasm for 2–30 years and a follow-up time of 5–77 months.
Clinical Manifestations
All patients manifested with sudden onset of unilateral muscle spasm with no obvious cause. This condition may also have been triggered by
Methods
The local ethics committee approved this study, and all subjects provided informed consent. Under general anesthesia, all of the patients received microvascular decompression of the trigeminal motor root through the suboccipital retrosigmoid approach. The responsible vessels were separated, and a Teflon pad was used to separate the responsible vessels from the trigeminal motor branch. Intraoperative electrophysiologic monitoring was used to identify the trigeminal motor branch. Four patients
Results
As shown in Table 1, of the 4 patients with simple vascular decompression, 1 case was cured with a delay and 3 cases were improved. Of these 3 cases, 1 case was worsened 2 years after the operation, 1 case was worsened 5 years after the operation, and 1 case showed no change during the follow-up period.
In the cases involving partial amputation of the trigeminal motor branch, 1 case was improved and 2 cases were cured after operation. Of these 2 patients, 1 recurred 2 years after surgery and 1
Discussion
Masticatory muscle spasm is a rare disorder of masticatory muscle movement with unknown etiology, which has been rarely reported in the literature. This condition manifests as paroxysmal involuntary movements of the involved muscle, usually on a unilateral basis, and can be either a short-term twitch or a long-term spasm of muscle. Severe spasm can lead to difficulty in mouth opening. Except for the muscle spasm under investigation, or accompanying local muscle hypertrophy, neurologic
Conclusion
Microvascular decompression and partial amputation of the trigeminal motor branches has been unable to achieve a satisfactory treatment effect on unilateral masticatory muscle spasm. Complete amputation of the trigeminal motor branch can achieve satisfactory results but may lead to mild temporal atrophy, which does not affect the face or restrict mouth opening. Surgical effects should be followed up and evaluated after a minimum of 2 years after surgery.
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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.