Botulinum toxin type A (BoNT-A) has been reported as an effective treatment for chronic migraine. When BoNT-A is injected on the frontalis muscle for chronic migraine, an unexpected clinical side effect called the "Mephisto sign" may occur. The aim of this article is to propose a method to eliminate or prevent the Mephisto sign side effect. A 25-year-old female patient visited the hospital and was diagnosed with chronic migraine. A total of 155 U of BoNT-A was injected into 31 sites. 2-weeks later, and the patient developed the Mephisto sign. An additional 2-U dose was administered bilaterally to the lateral-most point of the frontalis muscles, and the eyebrow morphology returned to normal within 2-3 weeks. We propose that the development of the Mephisto sign may be prevented with an additional BoNT-A injection of 2-4 U bilaterally to the lateral most point of the frontalis muscles during the primary injection process.
PurposeThe aim of this study was to determine the force distribution and pattern of mastication after injection of botulinum toxin type A (BTX-A) into both masseter muscles. The hypothesis to be tested was that the difference between right and left balance of occlusal force diminishes over time following BTX-A injection.Materials and MethodsFifteen patients were submitted to BTX-A injection therapy for subjective masseter hypertrophy. A total of 25 U of BTX-A (50 U in total) was injected into two points located 1 cm apart at the center of the lower one-third of both masseter muscles. All patients were examined using the T-Scan occlusion analysis system before and 4, 8, 12, and 24 weeks after BTX-A injection.ResultsA significant change in force balance was found between the right and left sides over time and the difference between the two sides decreased with the time post-injection, reaching a minimum at 12 weeks. Comparison of the force balance between the anterior and posterior occlusions revealed no significant difference at any of the time points. The occlusion and disclusion times (right and left sides) did not differ significantly with time since BTX-A injection.ConclusionA decline in the difference in the clenching force between the left and right sides was found with increasing time up to 12 weeks following BTX-A injection.
There have been reports regarding the various factors associated with the level of discomfort and recovery from neurosensory symptoms in patients with trigeminal nerve injury. However, the contributing factors remain uncertain and poorly understood. The purpose of this paper was to investigate the possible association between various factors expected to affect neurosensory discomfort and recovery in patients with mandibular nerve injury after dental implant surgery.Methods: Eighty-nine post-dental implant surgery patients with mandibular nerve injury were enrolled in this retrospective analysis. A medical records review of the patients was done to determine if the patients' improvement was related to pain intensity, the length of time between the injury and removal of the implant or the depth of penetration of the implant into the mandibular canal as determined by cone-beam computed tomography.Results: There was no significant linear relationship between pain intensity and symptomatic improvement (p=0.319). There was no significant linear relationship between the level of mandibular canal penetration and either pain intensity (p=0.588) or symptomatic improvement (p=0.760). There was a statistically significant linear relationship between length of time before the injury was treated, both with pain intensity (p=0.004), and symptomatic improvement (p=0.024). Conclusions:Our findings indicate that the length of time between nerve injury and initiation of conservative treatment is more closely related to the pain intensity and symptomatic improvement than other factors, including the level of mandibular canal invasion. Additionally, increased pain intensity and decreased symptomatic improvement can be expected over time, because of this linear trend. Therefore, although direct injury to the nerve is the most important factor contributing to a neurosensory disturbances, early neurosensory assessment and initiation of conservative treatment should be done to optimize recovery.
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