• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.11
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• pp.541-549
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• 2001

The term 'silent period(SP)' refers to a transitory, relative or absolute decrease electromyography(EMG) activity, evoked in the midst of an otherwise sustained contraction. Masseteric SP is elicited by a tap on the chin during isometric contraction of masseter muscle. In this paper, a new EMG signal generation model including SP in masseter muscle is proposed. This work is based on the anatomical structure of trigeminal nerve system that related on temporomandibular joint(TMJ) dysfunction. And it was verified by comparing the real EMG signals including SP in masseter muscle to the simulated signals by the proposed model. Through this studies, it was shown that SP has relation to variable neurophysiological phenomena. A proposed model is based on the control system theory and DSP(Digital Signal Processing) theory, and was simulated using MATLAB simulink. As a result, the proposed SP model generated EMG signals which are similar to real EMG signal including normal SP and an abnormal extended SP. This model can be applied to the diagnosis of TMJ dysfunction and can effectively explain the origin of extended SP.

• Journal of Oral Medicine and Pain
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• v.47 no.4
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• pp.217-221
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• 2022

Neurogenic muscular atrophy is muscle wasting and weakness caused by trauma or disease of the nerve that innervates the muscle. We describe a case of unilateral trigeminal neuropathy and neurogenic muscular atrophy of the masticatory muscle caused by a tumor in the foramen ovale. A 59-year-old man visited our clinic complaining of difficulty in right-sided mastication. There were no evident clinical signs and symptoms of temporomandibular disorder. However, severe atrophy of the right masseter and temporalis muscles and hypesthesia of the right side mandibular nerve area were confirmed. Through T1 and T2 signals on magnetic resonance imaging (MRI), a mass suspected of a neurogenic tumor was observed in the foramen ovale and cavernous sinus. Severe atrophy of all masticatory muscles on the right side was observed. This rare case shows trigeminal neuropathy caused by a tumor around the foramen ovale and atrophy of the ipsilateral masticatory muscles. For an accurate diagnosis, it is essential to identify the underlying cause of muscle atrophy with neurologic symptoms present. This can be done through a more detailed clinical examination, including sensory testing and brain MRI, and consider a referral to neurology or neurosurgery for the differential diagnosis of the intracranial disorder.

• Journal of Oral Medicine and Pain
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• v.45 no.4
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• pp.110-114
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• 2020

Myofascial pain (MFP) is one of the most common causes of persistent orofacial pain. Patients with chronic myofascial orofacial pain may present with diffuse heterotopic pain, complicating the correct diagnosis. Treatment of chronic MFP should focus on the elimination of aetiologic factors. This article describes two cases of chronic MFP of the masticatory muscles, whose symptoms were exacerbated after masseteric nerve neurectomy. The patients had suffered from irrelevant treatment which did not resolve the symptom. Their symptom was managed by conventional treatment protocol. These cases emphasize the importance of correct diagnosis and evidence-based approach.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.161-168
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• 2010

Purpose: Surgical approaches to the condylar neck and subcondyle area can cause some morbidity such as, facial nerve injury, time-consuming nature and external scar etc. So many surgeons hesitate using open reduction and internal fixation for the treatment of subcondylar fractures. We report open reduction and internal fixation of subcondylar fractures in 13 adult patients via transmasseteric approach. Methods: From 2007 to 2009, 13 adults with subcondylar fracture of mandible were treated with open reduction and internal fixation via transmasseteric approach. A preauricular incision was extended downwards in a curvilinear fashion in the cervicomastoid skin crease. Skin flap was elevated above the SMAS layer. Masseter muscle was splitted at the anteroinferior edge of the parotid gland. After the fracture was reduced, fixed with appropriate plates and screws. All operation were performed under general anesthesia. Results: Mean follow-up period was 13.3 months. There were no signs and symptoms of facial nerve injury, difficulty in mouth opening, or malocclusion. Dissection time was roughly within 30 minutes. Conclusion: Transmasseteric open reduction and internal fixation of mandible subcondylar fracture can be performed with excellent visualization, and inconspicuous scar. It also offers swift access to the subcondylar area while substatially reducing the risk to the facial nerve and eliminating the complications associated with transparotid approaches.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.325-331
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• 2013

Botulinum neurotoxin(BoNT) is a protease exotoxin produced from Clostridium botulinum. It works by blocking the release of acetylcholine from cholinergic nerve endings causing inactivity of muscles or glands. Recently, the therapeutic use of BoNT have expanded to include a wide range of medical and dental conditions. Botulinum neurotoxin type A(BoNT/A) is used off-label in the orofacial region to treat primary and secondary masticatory and facial muscle spasm, severe bruxism, facial tics, orofacial dyskinesias, dystonias, and hypertrophy of the masticatory muscles. Local hematoma, infection, and persistent pain in the injection site are the site-of-injection side effects. Medication-related side effects are adjacent muscle weakness, slurred speech, an alteration in the character of the saliva, and severe headaches. In most cases, these complications are not persistent and bothersome. We reported a case report of a patient who had transient anterior open bite after BoNT/A injection on masseter muscles to treat the refractory myofascial pain.

• Journal of Oral Medicine and Pain
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• v.34 no.1
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• pp.115-122
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• 2009

The following results were obtained, after experimenting on change of masseter muscle and bloodstream epithelium with Transcutaneous Electrical Nerve Stimulator(TENS), among 16 male adults. 1. According to applying TENS, it was observed that bloodstream in muscle increases at 1.5, 3.0 Hz. 2. According to applying TENS, it was observed that concentration of moving blood cells in muscle increase at 1.5, 3.0, 6.0 Hz. 3. According to applying TENS, it was observed that velocity of bloodstream in muscle increases only at 1.5 Hz 4. Through experiment, applying TENS at level of 6.0 and 10.0 Hz, all bloodstream, concentration of moving blood cells, and velocity of bloodstream increasing rates were lower in muscle compared to of them in overlying epithelium; and especially increasing bloodstream and its velocity were most frequent at 6.0 Hz, and bloodstream of 10.0 Hz. From the results above when a physical therapy of TENS is carried out the frequency of 1.5, 3.0 H is effective, and as the frequency increases it is disadvantageous to the muscle.

• The Korean Journal of Pain
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• v.22 no.2
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• pp.167-170
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• 2009

Pharmacological management is the first choice for treatment of the trigeminal neuralgia patients; however, if this mode of treatment fails a minimally invasive procedure should be performed. One of the most commonly used procedures is conventional radiofrequency lesioning of the Gasserian ganglion. Despite its popularity and success rate, this technique has disadvantages such as diminished corneal reflex, masseter weakness, numbness and anesthesia dolorosa. As a result, many studies have been conducted in an attempt to find a better method of treating trigeminal neuralgia. We report here a case of a trigeminal neuralgia patient that was treated with pulsed radiofrequency lesioning of the supraorbital and supratrochlear nerve due to pain in the frontal head that was refractory to the pharmacological treatments. Following the procedure, the Visual Analogue Scale score for pain decreased to 1-2/10 and the pain relief persisted for 7 months. These results indicate that pulsed radiofrequency treatment of the peripheral nerve may be useful for trigeminal neuralgia patients that do not respond to pharmacological treatments.

• Journal of Veterinary Science
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• v.22 no.2
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• pp.22.1-22.9
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• 2021

Background: Standing surgery in horses combining intravenous sedatives, analgesics and local anaesthesia is becoming more popular. Ultrasound guided (USG) peribulbar nerve block (PB) has been described in dogs and humans for facial and ocular surgery, reducing the risk of complications versus retrobulbar nerve block (RB). Objective: To describe a technique for USG PB in horse cadavers. Methods: Landmarks and PB technique were described in two equine cadaver heads (Phase 1), with computed tomography (CT) imaging confirming contrast location and spread. In Phase 2, ten equine cadaver heads were randomised to two operators naive to the USG PB, with moderate experience with ultrasonography and conventional "blind" RB. Both techniques were demonstrated once. Subsequently, operators performed five USG PB and five RB each, unassisted. Contrast location and spread were evaluated by CT. Injection site success was defined for USG PB as extraconal contrast, and for RB intraconal contrast. Results: Success was 10/10 for USG PB and 0/10 for RB (p < 0.001). Of the RB injections, eight resulted in extraconal contrast and two in the masseter muscle (p = 0.47). Conclusions: The USG PB had a high injection site success rate compared with the RB technique; however, we cannot comment on clinical effect. The USG technique was easily learnt, and no potential complications were seen. The USG PB nerve block could have a wide application for use in horses for ocular surgeries (enucleations, eyelid, corneal, cataract surgeries, and ocular analgesia) due to reduced risk of iatrogenic damage. Further clinical studies are needed.

• Physical Therapy Rehabilitation Science
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• v.9 no.4
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• pp.244-251
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• 2020

Objective: Physical therapy techniques are required for patients with temporomandibular joint disorder (TMD), but the effects of treatment have not been compared. Therefore, effects of transcutaneous electrical nerve stimulation (TENS) and low level laser (LLL), which are most commonly used interventions, were compared. Design: Randomized controlled trial. Methods: Thirty-six participants with pain in the temporomandibular joint were enrolled, and 12 participants were randomly assigned to either the TENS group, LLL group, or placebo group. Each intervention was performed for a total of 6 sessions for 2 weeks. For the evaluation of the participants, the mouth opening (MO), pressure pain threshold (PPT), and stress were measured at three time periods: baseline, post-test, and follow-up at 2 weeks. Results: Significant interaction between groups according to each evaluation point was found only in PPT-masseter (p<0.05). The evaluation time point at which a significant difference appeared was at the post-test and follow-up at 2 weeks time periods. As a result of the post-test, the LLL group showed a significant improvement compared to the TENS group (p<0.05), and at 2 weeks follow-up, the TENS group showed a significant improvement compared to the placebo group (p<0.05). Conclusions: In this study, an experiment was conducted to compare the treatment effects when TENS, LLL, and placebo were given to patients with TMD. In addition, by quantitatively presenting the effect size of each treatment, this study suggests clinical use of TENS and LLL treatment for TMD.

• Archives of Craniofacial Surgery
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• v.22 no.2
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• pp.115-118
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• 2021

Intramuscular hemangioma is a rare vascular benign proliferation that can occur within any muscle, particularly in the trunk and extremities. In the head and neck region, the masseter muscle is most commonly involved, followed by the periorbital and sternocleidomastoid muscles. Diagnosing intramuscular hemangioma is challenging because there are no characteristic symptoms; instead, magnetic resonance imaging is the best imaging modality to diagnose these lesions. Complete surgical resection is the treatment of choice, although the local recurrence rate is high. Herein, we report a rare case of intramuscular hemangioma located in the zygomaticus minor muscle, which is related to smiling and usually runs along the orbicularis oculi muscle. Distinguishing or separating these two muscles is challenging. However, based on the muscle vector of the midface and radiological findings, the two muscles were successfully separated. The zygomaticus minor was cut very slightly to approach to the lesion and the muscle fibers were split to excise it. A follow-up examination revealed no nerve damage or muscle dysfunction at 4 weeks postoperatively. This rare case may serve as a reference for managing intramuscular hemangioma in the head and neck region.