• Archives of Craniofacial Surgery
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• v.21 no.6
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• pp.337-344
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• 2020

Facial paralysis is a devastating disease, the treatment of which is challenging. The use of the masseteric nerve in facial reanimation has become increasingly popular and has been applied to an expanded range of clinical scenarios. However, appropriate selection of the motor nerve and reanimation method is vital for successful facial reanimation. In this literature review on facial reanimation and the masseter nerve, we summarize and compare various reanimation methods using the masseter nerve. The masseter nerve can be used for direct coaptation with the paralyzed facial nerve for temporary motor input during cross-facial nerve graft regeneration and for double innervation with the contralateral facial nerve. The masseter nerve is favorable because of its proximity to the facial nerve, limited donor site morbidity, and rapid functional recovery. Masseter nerve transfer usually leads to improved symmetry and oral commissure excursion due to robust motor input. However, the lack of a spontaneous, effortless smile is a significant concern with the use of the masseter nerve. A thorough understanding of the advantages and disadvantages of the use of the masseter nerve, along with careful patient selection, can expand its use in clinical scenarios and improve the outcomes of facial reanimation surgery.

• Archives of Plastic Surgery
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• v.46 no.2
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• pp.122-128
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• 2019

Background The masseter nerve is a useful donor nerve for reconstruction in patients with established facial palsy, with numerous advantages including low morbidity, a strong motor impulse, high reliability, and fast reinnervation. In this study, we assessed the results of masseter nerve-innervated free gracilis muscle transfer in established facial palsy patients. Methods Ten patients with facial palsy who received treatment from January 2015 to January 2017 were enrolled in this study. Three patients received masseter nerve-only free gracilis transfer, and seven received double-innervated free gracilis transfer (masseter nerve and a cross-face nerve graft). Patients were evaluated using the Facial Assessment by Computer Evaluation software (FACEgram) to quantify oral commissure excursion and symmetry at rest and when smiling after muscle transfer. Results The mean time between surgery and initial movement was roughly 167.7 days. A statistically significant increase in excursion at rest and when smiling was seen after muscle transfer. There was a significant increase in the distance of oral commissure excursion at rest and when smiling. A statistically significant increase was observed in symmetry when smiling. Terzis' functional and aesthetic grading scores showed significant improvements postoperatively. Conclusions Masseter nerve innervation is a good option with many uses in in established facial palsy patients. For some conditions, it is the first-line treatment. Free gracilis muscle transfer using the masseter nerve has excellent results with good symmetry and an effective degree of recovery.

• Archives of Craniofacial Surgery
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• v.20 no.6
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• pp.388-391
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• 2019

Schwannoma is a slow-growing, well-demarcated, benign soft tissue tumor of the peripheral nerve sheath. It commonly develops in the head and neck region, usually in the parapharyngeal space. In this case, a 42-year-old woman visited the outpatient department to manage a painless mass on her left cheek. She had no history of concern and no neurological symptoms were observed. In the enhanced computed tomography scan, a 2.8×2.8×1.8 cm, heterogeneously enhanced tumor was detected in the left masseter muscle. A tumor resection under general anesthesia was planned. For the resection, a facelift incision was chosen; branches of the facial nerve were identified and retrogradely dissected. A well-marginated, yellowish, solid mass was found in the left masseter muscle. The mass was excised and given a histopathological diagnosis of schwannoma. A definite diagnosis of schwannoma, originating in the masseter muscle, is difficult to arrive at with radiographic findings alone; it is often misdiagnosed as intramuscular hemangioma. Histopathological examinations, including fine-needle aspiration or histological biopsy after surgery, are necessary. Using a facelift incision with retrograde facial nerve dissection, tumor resection in an intramasseteric lesion can be performed efficiently, without nerve damage, or leaving conspicuous scars on the face.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.1
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• pp.46-48
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• 2017

A patient, who underwent partial masseter muscle resection and mandibular angle reduction at a plastic surgery clinic, visited this hospital with major complaints of trismus and dysesthesia. A secondary angle formation due to a wrong surgical method was observed via clinical and radiological examinations, and the patient complained of trismus due to the postoperative scars and muscular atrophy caused by the masseter muscle resection. The need for a masseter muscle resection in square jaw patients must be approached with caution. In addition, surgical techniques must be carefully selected in order to prevent complications, and obtain effective and satisfactory surgery results.

• The Korean Journal of Pain
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• v.30 no.4
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• pp.304-307
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• 2017

A 19-year-old male patient presented with facial hemi-atrophy with unilateral spasms of the masseter and temporalis muscles. Ultrasound therapy and Transcutaneous Electric Nerve Stimulation therapy, known as combination therapy, were given on alternate days for 2 weeks. At the end of 2 weeks of combination therapy the patient reported a drastic reduction in the number of episodes of muscle spasm. The visual analog scale score for tenderness of the masseter and temporalis was also markedly reduced. No one has previously used combination therapy for the treatment of facial hemi-atrophy with hemi-facial spasms. The encouraging results of the combination therapy has prompted us to document this study.

• The Korean Journal of Pain
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• v.29 no.1
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• pp.12-17
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• 2016

Background: The study aimed to determine if ultrasonography of masseter can be used to evaluate the outcome of transcutaneous electrical nerve stimulation (TENS) in subjects with temporomandibular disorders (TMDs) such as myositis and myofascial pain. Methods: Fifteen TMD subjects with myofascial pain/myositis who satisfied the RDC/McNeil criteria were included in the study. All the subjects were administered TENS therapy for a period of 6 days (30 minutes per session). The mouth opening (in millimeters) and severity of pain (visual analogue scale score) and ultrasonographic thickness of the masseter (in millimeters) in the region of trigger/tender areas was assessed in all the subjects both prior and post TENS therapy. A comparison of the pre-treatment and post-treatment values of the VAS score, mouth opening and masseter thickness was done with the help of a t-test. Results: There was a significant reduction in the thickness of masseter muscle (P = 0.028) and VAS scores (P < 0.001) post TENS therapy. There was also a significant improvement in the mouth opening (P = 0.011) post TENS therapy. Conclusions: In the present study, ultrasonography was found to be an effective measuring tool in the assessment of TENS therapy in subjects with myositis and myofascial pain.

• The korean journal of orthodontics
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• v.20 no.1
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• pp.23-45
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• 1990

It is the aim of this study to determine the effects of facial denervation on physiological properties of facial muscles and facial bones in growing rabbits. Experimental animals of fifty two Oryctolagus cuniculus rabbits were employed. Unilateral dissection of facial nerve was carried out on twelve rabbits, bilateral dissection of facial nerve was made on another twelve rabbits and the other twenty rabbits were on unilateral dissection of facial nerve for the histochemical analyses. Six rabbits on the bilateral surgical sham operations and six rabbits of non-intervention served the control groups. EMG records of the orbicularis oris, buccinator and masseter muscles as well as lateral and dorsoventral cephalometric films were taken and analyzed at 0, 1, 2, 5 and 8 weeks respectively. The orbicularis oris, buccinator and masseter muscles of both sides were removed from the animals of the histochemistry group and muscle fibers were classified on the basis of histochemical staining for $\alpha$-GPD, NADH-D and myosin ATPase. EMG activities of orbicularis oris and buccinator muscles were vanished immediately after denervation. Recovery of activities were detected one week after denervation in buccinator and five weeks in orbicularis oris muscles. Histochemical properties of masseter muscles remained as fast glycolytic through the experimental period. Orbicularis oris muscle fibers showed the gradual diminution of size and ratio of the slow oxidative fibers accompanied with atrophy, phagocytosis and vacuolation as well as the augmentation of fast oxidative glycolytic fibers. The buccinator muscle manifested the augmentation of fast oxidative glycolytic fibers at five weeks of experiment. Visual changes in morphology of craniofacial area were not evident, however it variety of subtle changes were apparent from statistical analysis of cephalometric measurements. It is concluded facial nerve regulates the physiological properties of facial muscles and interrelation between the function of the facial muscles and changes of facial bones would be in some degrees.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.2
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• pp.112-119
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• 2003

This paper proposes a model of SP(silent period) generation in masseter muscle by means of computer simulation. The model is based on the anatomical and physiological properties of trigeminal nervous system. In determining the SP generation pathway, evoked SPs of masseter muscle after mechanical stimulation to the chin are divided into normal and abnormal group. Normal SP is produced by the activation of mechanoreceptors in periodontal ligament. The activation of nociceptors contributes to the latter part of normal SP, abnormal extended SP is produced. As a result, the EMG signal generated by a proposed SP generation model is similar to both real EMG signal including normal SP and abnormal extended SP with TMJ patients. The result of this study have shown differences of SP generation mechanism between subjects both with and without TMJ dysfunction.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.2
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• pp.215-219
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• 1999

This article discusses the diagnosis, anatomic consideration, and surgical management of masseter muscle hypertrophy. Surgical correction is advised for patients who have esthetic complaints. Esthetic improvement can be achieved by surgery and not by conservative treatment. Recently, the intraoral method, which leaves no scar on the face and minimizes the possibility of injury to the marginal branch of the facial nerve, has been supported by many surgeons. Patients who complained of marked swelling of unilateral or bilateral mandibular angle area and showed abnormal bony growth at the mandibular angle area and enlarged masseter muscle received mandibular angle shaving and excision of the inner layer of masseter muscle with intraoral approach. After operation, physiotherapy was done with EAST(eletrical acupuncture stimulation therapy) for encouraging the mouth opening and reducing the swelling. They showed early maximum mouth opening and reduction of swelling.

• Archives of Craniofacial Surgery
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• v.25 no.1
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• pp.1-10
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• 2024

The facial nerve stimulates the muscles of facial expression and the parasympathetic nerves of the face. Consequently, facial nerve paralysis can lead to facial asymmetry, deformation, and functional impairment. Facial nerve palsy is most commonly idiopathic, as with Bell palsy, but it can also result from a tumor or trauma. In this article, we discuss traumatic facial nerve injury. To identify the cause of the injury, it is important to first determine its location. The location and extent of the damage inform the treatment method, with options including primary repair, nerve graft, cross-face nerve graft, nerve crossover, and muscle transfer. Intracranial proximal facial nerve injuries present a challenge to surgical approaches due to the complexity of the temporal bone. Surgical intervention in these cases requires a collaborative approach between neurosurgery and otolaryngology, and nerve repair or grafting is difficult. This article describes the treatment of peripheral facial nerve injury. Primary repair generally offers the best prognosis. If primary repair is not feasible within 6 months of injury, nerve grafting should be attempted, and if more than 12 months have elapsed, functional muscle transfer should be performed. If the affected nerve cannot be utilized at that time, the contralateral facial nerve, ipsilateral masseter nerve, or hypoglossal nerve can serve as the donor nerve. Other accompanying symptoms, such as lagophthalmos or midface ptosis, must also be considered for the successful treatment of facial nerve injury.