Neurectomy of the Masseteric Nerve Using an Extra-Oral Approach to Treat Masseter Hypertrophy: Case Report and Literature Review.

Masticatory muscle hypertrophy is a benign clinical anomaly which leads to facial asymmetry or a squared face appearance. We report a case of masticatory muscle hypertrophy, particularly on the right side, that was successfully treated by neurectomy of the right masseteric nerve through an extra-oral approach. Clinical examination showed significant aesthetic improvement of the facial symmetry with complete paralysis and atrophy of the right masseter muscle. The impaired postoperative function of the frontal branch of the right facial nerve was fully restored 10 weeks postoperatively. The patient no longer experiences headaches or discomfort with eating or sleeping on her right side.

Functional reconstruction of the masseter muscle by microvascular free gracilis muscle transfer: technique and outcome.

Microvascular reconstruction of the cheek is most often performed using fasciocutaneous flaps and without functional reconstruction of the masseter muscle. This article reports a technique of masseter muscle resection, dissection of the masseteric nerve, and masseter muscle reconstruction with a functional gracilis muscle flap. The technique was applied in a 38-year-old man with recurrent intramuscular lipoma of the right masseter muscle. The flap was highly stable in form and showed good function. Bite force, electromyography results, and the radiological appearance of the gracilis muscle were similar to those of the contralateral masseter muscle at 12 months after surgery. In conclusion, full rehabilitation of masseter muscle function and good facial aesthetics were achieved by functional gracilis muscle reconstruction of the masseter muscle in a case of total resection.

The Five Ds for Safe and Effective Buccal Fat Removal.

SUMMARY: An aesthetically sculpted malar, cheek, and jawline contour is a desirable feature sought out by many adults with central facial adiposity. This fullness, anterior to the masseter, can be attributed to underlying buccal lipodystrophy. An attractive central facial concavity can be delivered by performing buccal fat pad excision in conjunction with malar fat pad augmentation and mandibular contouring if indicated. Appropriate patient selection is critical for preventing an aged or unnatural appearance. The authors present a safe and reliable five-step technique for buccal fat pad excision: the Five Ds.

Surgical Anatomy for Asian facial Contouring: A Personal Perspective.

This paper introduces my personal perspective on anatomic structures for reduction malarplasty, mandibular contouring surgery, and masseter muscle resection. The zygomaticofacial nerve innervates a rectangular area, and each side measures 18.8±4 and 15.8±3.4 mm. The center of the rectangle is located laterally, at 17.3±5.5 mm from the lateral canthus, and then inferiorly, at 18.1±3.1 mm. The point of the zygomaticotemporal nerve appears at the margin of the zygomatic bone, 11.29±2.65 mm below the zygomaticofrontal suture and 21.76±2.76 mm from the superior border of the zygomatic arch. The inferior alveolar nerve in the mandibular canal runs above the lower one-third of the mandibular body. The terminal mandibular canal is located at an average of 4.5 mm under the mental foramen, advances 5.0 mm anteriorly, loops, and ends at the foramen. The facial nerve trunk is located 11 to 14 mm medial to the posterior border of the mandible. The trunk emerges out of the stylomastoid foramen and runs anteroinferiorly at an angle of 45°. The deep branch of the middle masseteric artery travels deep in the muscle, close to the periosteum of the mandible in 94% of cases. The average diameter is 1.23±0.26 mm. The masseteric nerve runs anteriorly and inferiorly between the deep and the middle layers of the masseter. It is observed at 33±5.6 mm from the inferior border of the muscle on the anterior third vertical line of the masseter muscle and at 47±5.5 mm in the posterior third.

Masseteric nerve position on the "temporomandibular joint-chin tip" artificial axis: an anatomical study.

PURPOSE: The use of the masseteric nerve develops in the surgery of facial paralysis rehabilitation. The objective of this study was to determine the topography of the masseteric nerve and to deduce and predict a precise and reproducible anatomical cluster to facilitate its clinical identification during V-VII neurotization surgery. METHOD: For the purpose of this work, a cadaveric study was performed on 31 hemi-faces. All dissections were performed bilaterally and comparatively, following steps aiming at simulating, as close as possible, the clinical conditions of a facial palsy rehabilitation by V-VII anastomosis. RESULT: For the identification of the masseteric nerve, bony reference points were used, i.e., the temporomandibular joint (TMJ) and the chin point (CT). A virtual axis was drawn between the TMJ and the CT, and the distance [TMJ-MN] determining the smallest length h was then plotted against the distance [TMJ-CT] determining the largest length H, thus allowing the calculation of an h/H proportion ratio (PR) indicating the proximal part of the masseteric nerve from the TMJ. The average length h between the TMJ and the NM was 3.5 cm (± 0.1 cm) from the TMJ, i.e., an average ratio h/H [TMJ-MN]/[TMJ-CT] of 28.1% 4.0 and a median ratio of 28.6% of the distance [TMJ-CT]. CONCLUSION: Our study opens new perspectives for facilitating its identification and use, offering practitioners a tool to make V-VII the neurotization procedure less complex, with the eventual prospect of a minimally invasive procedure combining imaging, surgery, and augmented reality.

The masseter muscle thickness is a predictive marker for postoperative pneumonia after endovascular aneurysm repair.

PURPOSE: Oral frailty is characterized by a decrease in the oral and swallowing function and is a risk factor for pneumonia. In the current study, we analyzed the association between the masseter muscle thickness (MMT) and postoperative pneumonia and mortality after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm. METHODS: Overall, 247 patients were retrospectively evaluated. The primary end point was postoperative pneumonia. The MMT was measured as the maximum thickness of the masseter muscle 2 cm caudal to the zygomatic arch using computed tomography images obtained within 3 months before EVAR. Pneumonia was defined as the presence of progressive infiltrates, consolidation, or cavitation on imaging and a fever or leukocytosis. RESULTS: Twenty (8.1%) cases of postoperative pneumonia occurred within 1 year after EVAR. We found that patients with a low MMT (≤ 30th percentile: males, 10.4 mm; females: 8.8 mm) had a significantly higher risk of developing postoperative pneumonia within 1 year after elective EVAR than those with a high value. A comparison of the utility of the MMT and psoas muscle index (PMI) for predicting the 1-, 3-, and 5-year all-cause mortality revealed that the MMT had superior predictive performance. CONCLUSION: The MMT before elective EVAR predicted postoperative pneumonia and life expectancy, and its predictive performance was superior to that of the PMI.

Facial Reanimation Using Free Functional Muscle Transfer: Lessons Learnt From a Long Term Experience Comparing Innervation With Cross Facial Nerve Graft and Masseter Nerve.

BACKGROUND: Facial palsy is a complex problem and goal of reanimation is to achieve symmetric face at rest and spontaneous smile. in our study the authors performed facial reanimation in long standing cases of facial palsy (more than 1 year), gracilis muscle was used as a free functioning muscle transfer. Two motor donor nerves were used: cross-face nerve graft and masseter nerve. MATERIALS AND METHODS: A total of 205 cases of unilateral facial reanimation with free functional muscle transfer (FFMT) were performed between 1998 and 2019. Out of 205 patients, 184 patients were operated by cross facial nerve graft-gracilis, and 21 by masseter nerve-gracilis. Quantitative assessment for outcome was done by measuring the excursion on follow up. Oral competence outcome and satisfaction score calculation was done by questionnaire. Results of spontaneous smile were divided into positive and negative groups. RESULTS: A 2 stage cross facial nerve graft-gracilis FFMT achieved most natural and spontaneous smile when longer observation period (≥2 years) was followed. Masseter nerve-gracilis provided satisfactory results in the shortest rehabilitation period, had more excursion but never obtained spontaneous smile. CONCLUSIONS: The cross facial nerve graft-gracilis FFMT can achieve natural and spontaneous smile and remains our first choice for facial reanimation. Masseter nerve-gracilis can be used if cross facial nerve graft-gracilis fails, patient desires a single stage surgery and in some specific conditions, such as bilateral mobius syndrome.

Masseter idiopathic calcinosis circumscripta: A rare condition.

Calcinosis is defined as a biomineralization occurring in soft tissues leading to ectopic calcification. Isolated and localised calcification in a muscle is rare, and it is called calcinosis circumscripta in opposition to calcinosis universalis wich is seen in juvenile dermatomyositis and polymyositis. According to laboratory findings and clinical history, calcinosis circumscripta can be metastatic, dystrophic or idiopathic. Masseter muscle is rarely involved. Pre-operative diagnosis of masseter idiopathic calcinosis is a challenge because of many differential diagnosis. Here, we report a case of 22 years old women presented with swelling over left middle third of her face. Clinical history, morphologic and laboratory examinations helped considering such a rare diagnosis.

Efficacy Evaluation of Temporomandibular Arthroscopic-Assisted Masseter Nerve Avulsion on Hemimasticatory Spasm.

PURPOSE: Hemimasticatory spasm (HMS) is a masticatory muscle disorder without an effective treatment approach at present. This retrospective analysis aims to investigate the clinical efficacy of temporomandibular arthroscope-assisted masseteric nerve avulsion on HMS and thereby further determine a more effective therapeutic strategy for HMS patients. METHODS: Four patients with HMS receiving temporomandibular arthroscope-assisted masseteric nerve avulsion in the neurology department of oral surgery of our hospital from April 2017 to April 2018 were recruited in this study. Through a clinical follow-up period of 36 months, the comprehensive efficacy of arthroscope-assisted masseteric nerve avulsion was evaluated combined with an electrophysiological electromyogram. Furthermore, the maximum muscle strength and masticatory efficiency of the sound and affected sides were measured to determine whether there were complications. The morphology of the myelin sheath of the masseteric nerve avulsed in the operation was observed under the transmission electron microscope. RESULTS: The 3 years of follow-up showed that complete remission of HMS was seen in 4 patients with the score reduced to grade 0, showing satisfactory clinical efficacy. Electrophysiological electromyogram demonstrated an absence of obvious high-frequency group discharge potential in the 4 patients within 3 years after the operation, and the overall efficacy combined with the clinical efficacy was considered satisfactory. The maximum masseter strength of the sound side had no significant change, but that of the affected side was slightly decreased. The masticatory efficiency of the affected side was slightly decreased immediately after the operation but returned to the preoperative level 1 year after the operation, suggesting that this operation did not affect the masticatory function of the patients. No obvious demyelination was found in the avulsed nervous tissues. CONCLUSIONS: Temporomandibular arthroscope-assisted masseteric nerve avulsion yielded satisfactory and stable overall efficacy on the treatment of HMS. The masticatory efficiency of the affected side was optimally preserved, while the maximum masseter muscle strength of the affected side was partially decreased.

Reduction Mandibuloplasty Along with Partial Masseter Muscle Resection: Masseter Muscle Response and Bone Regeneration.

OBJECTIVE: To compare the masseter muscle changes and bone regeneration between reduction mandibuloplasty along with partial masseter muscle resection and reduction mandibuloplasty alone. METHODS: Forty-seven patients who complained of prominent mandibular angle and hypertrophy masseter muscles (MMH) were divided into group 1 treated with reduction mandibuloplasty along with partial masseter muscle resection, and group 2 treated with reduction mandibuloplasty alone. Pre-5 days and long-term postoperative computed tomography data were collected, and the masseter muscle volume, hemi-mandible volume, and unilateral lower face width were measured. Patient satisfaction and complication were also evaluated. RESULTS: At long-term follow-up, group 1 showed a greater decrease in masseter volume (p < 0.001), and lower face width (p < 0.001), and less bone regeneration (p < 0.001) than group 2. Furthermore, patients in group 1 had higher satisfaction with the surgical outcome (p < 0.05). CONCLUSION: Reduction mandibuloplasty along with partial masseter muscle resection can achieve a slender frontal appearance and significantly decrease bone generation. For patients with MMH, reduction mandibuloplasty along with partial masseter muscle resection is an effective and predictable lower face reshaping surgery. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266 .

Masseter muscle flap for reconstruction of intra-oral defects in patients with early cancer of posterior-inferior parts of the oral cavity.

INTRODUCTION: Early carcinomas of the oral cavity in the posterior-inferior regions poses a challenge for reconstruction due to the lack of muscle support underneath and the limited space available to use some of the frequently-used flaps. OBJECTIVE: This study was done to evaluate the efficacy of the superiorly based masseter muscle flap in reconstruction of intra-oral post- ablation defects in patients with early oral carcinoma of the posterior-inferior part of the oral cavity. METHODS: A superiorly based masseter muscle flap were used to reconstruct the post-surgical intra- oral defect in 60 patients with early squamous cell carcinoma (T<4cm) of the posterior-inferior part of the oral cavity. The patients were followed up at 1-week and 1-month postoperatively to check for flap viability, complications, change in mouth opening and deviation of the mandible on mouth opening. To rule out any recurrence in the oral cavity masseter flaps, the patients were followed up for 1 year. RESULTS: The flap was viable in all patients and underwent mucosalization. 7/60 patients had postoperative infections, while 2/60 patients developed an oro-cutaneous fistula which required a secondary corrective procedure. The mean±standard deviation of change in mouth opening at 1 week postoperatively was +1.917±3.36mm, which increased to +2.633±2.95mm at 1 month after surgery. The Friedman test revealed that there was a statistically significant change in mouth opening from preoperative period to the1 week and 1 month postoperative periods (p=0.000). Female patients showed better improvement in mouth opening postoperatively. The ipsilateral deviation of the mandible on mouth opening was between 0-5mm in 39 patients, 5-10mm in 17 patients and more than 10mm in 4 patients. There were no recurrences noted in the masseter flaps used. CONCLUSION: The study infers that the superiorly based masseter muscle flap is a reliable method for reconstruction in early oral cancer patients yielding good functional results and acceptable cosmesis with nominal postoperative complications.

The Masseteric-Facial Anastomosis With Intratemporal Translocation of the Facial Nerve: Step-by-Step Technique and Results.

BACKGROUND: In the absence of a viable proximal nerve stump, damaged after surgical procedures around the skull base, numerous techniques for facial reanimation have been developed over time, aiming to restore baseline symmetry and active mimicry. OBJECTIVE: To report experience using the masseteric nerve as a direct transfer to the facial nerve rerouted after intratemporal translocation. This paper illustrates the main steps of the technique and the quality of results. METHODS: Eleven patients were treated with a masseteric direct transfer to the facial nerve. Its extratemporal rerouting toward the zygoma allowed tension-free coaptation between donor and recipient nerves. RESULTS: Of the 11 patients, 8 had a good to excellent recovery, showing different patterns of time and scores, according to age, surgical timing, and masseteric nerve function quality. The return of activity in the frontalis muscle, never obtained after reinnervation via the hypoglossal nerve, is of particular interest. The quality of the smile can be improved with re-education and practice but remains under volitional control. A true emotional response is still lacking. CONCLUSION: The masseteric nerve is an excellent alternative to the hypoglossal nerve and can reinnervate the whole territory of the facial nerve rerouted after intratemporal translocation. The overall results are remarkable, but the low quality of the trigeminal nerve, eventually affected by the first surgery, may be an important limitation. Even if the patients appear more at ease in re-education than with other techniques, a fully natural facial expression remains impossible to obtain.

Dual Innervation of Free Functional Muscle Flaps in Facial Paralysis.

Dual innervation in free muscle flap facial reanimation has been used to create a functional synergy between the powerful commissure excursion that can be achieved with the masseter nerve and the spontaneity that can be derived from a cross-face nerve graft. The gracilis has been the most frequently used muscle flap, and multiple combinations of neurorrhaphies have been described, including the masseter to the obturator (end-to-end) combined with a cross-face nerve graft to the obturator (end-to-side) and vice versa. Single and staged approaches have been reported. Minimally, dual innervation is as effective as using the motor nerve to masseter alone.

How Does a Unilateral Temporomandibular Joint Replacement Affect Bilateral Masseter and Temporalis Muscle Activity?-A Prospective Study.

PURPOSE: Total alloplastic temporomandibular joint replacement (TMJR) requires the detachment of the masseter muscle (MM) at its insertion to the lateral ramus and often the resection of the coronoid process (insertion of the temporalis muscle). There is little literature on how a detachment affects the muscles. The present study evaluates the long-term masticatory muscle activities and maximum voluntary bite force (MVC) in patients with unilateral TMJR. PATIENTS AND METHODS: Surface electromyography of the MM and anterior temporalis muscle during bite force testing and MVC were evaluated bilateral preoperatively (T0), 1 (T3), 2 (T4), 3 (T5), and 4 years (T6) postoperatively. The percentage overlapping coefficient (index of the symmetric distribution of muscular activity) was calculated. Differences between stock or custom devices were evaluated. RESULTS: Fourteen patients were enrolled, 4 males and 10 females, age 47.3 ± 14.3 years at TMJR placement. In 11 patients, the coronoid process was resected, 5 patients received stock, and 9 custom prostheses. After surgery, a trend in the improvement of bilateral surface electromyography activities and MVC was found without statistical significance for the side comparison or the time of the investigation. The percentage overlapping coefficient values showed postoperatively relative (>72%) symmetry in both muscles. Up to T5 on the TMJR side, MM showed higher activity when custom prostheses were used. There was no significant difference between stock and custom prostheses. CONCLUSIONS: The vertical (anterior) fibers of the temporalis muscle are preserved despite the resection of the coronoid process. The anterior temporalis muscle, as a synergist of the MM on the TMJR side, postoperatively partially assumes its abduction function. The detached MM appears to reattach. Generally, the bilateral increase in muscle activity and MVC of both muscles suggests regeneration of the investigated muscles. Custom prostheses seem to have an initial advantage for the reattachment of the MM compared with stock prostheses.

Predicting Resting Oral Commissure Tone Outcomes Following Masseter Nerve Transfer in Facial Reanimation.

Objective: To quantify the degree of oral commissure resting tone improvement in patients undergoing masseter to facial nerve transfer. Methods: A retrospective cohort study was completed in a tertiary academic medical practice. Consecutive cases of masseter nerve transfer patients within a patient database were evaluated from 6/2012 to 9/2017. Inclusion criteria were patients >18 years of age, with complete unilateral paralysis, receiving a masseter to facial nerve transfer, with at least 12 months of recovery, and possessing complete pre- and postoperative data. Patients were excluded if a simultaneous adjunctive procedure was performed so that tone could not be attributed to masseter transfer alone. The main outcome measure was the facial asymmetry index (FAI): the measured difference in distance between the medial canthus and oral commissure of the healthy and paralyzed sides. Results: Twenty-nine patients met inclusion and exclusion criteria and were further analyzed for this study. The oral commissure symmetry improved from 4.7 ± 2.8 mm preoperatively to 2.2 ± 2.3 mm postoperatively. In multivariate analysis, the preoperative FAI was the only significant predictive factor for improvement in commissure symmetry at rest (r = 0.589). This suggests that for each 1.0 mm of worse preoperatively oral commissure asymmetry, the improvement postoperatively was 0.6 mm. Age, gender, body mass index, side of paralysis, duration of paralysis, and recipient branch of facial nerve were not significant predictors in a multivariate analysis. Conclusion: Masseter to facial nerve transfer yields an estimated 60% correction in the oral commissure asymmetry. This estimation may be helpful in determining if adjunctive procedures should be utilized.

Circumscribed Myositis Ossificans of the Masseter Muscle.

ABSTRACT: The authors report a case of myositis ossificans traumatica of the masseter muscles. A 21-year-old man developed masseter myositis after orthognathic surgery to treat facial asymmetry. The myositis may have been triggered by factors such as calcification of a hematoma, periosteum implantation after surgical trauma, and local soft tissue injury. An intraoral incision was made to excise the ectopic bone, resulting in resolution of the patient's symptoms including limited oral opening.

Sinocutaneous fistula repair with a masseter muscle transposition flap combined with wound matrix and cancellous bone graft in a horse: A new technique.

OBJECTIVE: To describe a new technique to repair a sinocutaneous fistula with a masseter muscle transposition flap. STUDY DESIGN: Case report. ANIMAL: One 13-year-old thoroughbred stallion. METHODS: One 13-year-old stallion with a 3.5 × 6-cm sinocutaneous fistula over the right caudal maxillary sinus was treated with a transpositional masseter muscle flap. This repair consisted of a commercial wound matrix dressing placed directly over the hole in the maxilla and secured with suture material; a cancellous bone graft collected from the right tuber coxa placed on the dressing; and a portion of the superficial layer of the masseter muscle, with its pedicle at the facial crest, transposed dorsally over the bone graft, followed by a rotational skin flap with skin rostral to the fistula to close the defect. RESULTS: Seroma formation and dehiscence of the skin flap occurred, but the transposed muscle flap survived, and the technique resulted in successful closure of the sinocutaneous fistula with excellent cosmetic and functional outcome. CONCLUSION: A chronic maxillary sinocutaneous fistula was successfully treated by using a transposition flap of the masseter muscle and a rotational skin flap with minor complications. CLINICAL IMPACT: Transposition of the superficial layer of the masseter muscle should be considered for a repair of large maxillary sinocutaneous fistulas in horses.

Evaluation of Complications Following a Trans-masseteric Antero-parotid Approach for Patients with Sub-condylar Fractures of Their Temporomandibular Joint. A Retrospective Study.

Sub-condylar fractures of the temporomandibular joint can be treated by an extraoral or intraoral approach. Trans-masseteric antero-parotid approach (TMAP) is an extraoral approach utilising a retromandibular incision. The authors evaluated patients' status and any complications of using TMAP from the years 2013-2017. There were 39 patients (44 fractures). When using TMAP, in 43 fractures the fragments were favourably positioned, in one case the position was compromised. Of the complications, postoperative palsy of the facial nerve was reported 6.8% - in all cases this was only temporary. Late occlusion had an equal number of complications (in 2 cases this was as a result of an infectious complication of the wound, and in 2 cases due to resorption of the proximal fragment). Muscular pain and dysfunction of the temporomandibular joint following trauma were observed consistently in 6.8% of patients. Sialocoele, a non-conforming scar, and infectious complications were observed in 4.5% of patients. TMAP allows rapid surgical performance, with a good view for perfect repositioning and fixation of fragments of sub-condylar fractures of the temporomandibular joint. The complications associated with this approach are, for the most part, temporary, the aesthetic handicap of a scar is considered by patients to be acceptable. Overall, it is possible to evaluate retromandibular TMAP as safe, and the authors recommended it for treatment of sub-condylar fractures of the mandible.