Securing the coronoid process during a coronoidotomy

Sagittal application of a titanium mini screw in the coronoid process at the time of coronoidotomy is a very efficient method for easy removal.

Changes in the masseter muscle after curved osteotomy of the prominent mandibular angle

BACKGROUND

This study aimed to explore the changes in the masseter muscle after curved osteotomy of the prominent mandibular angle and to supply guidance for resection of the mandibular angle.

METHODS

Ultrasonography was used to assess changes in the thickness of the masseter muscle after curved osteotomy for 10 patients (20 hemimandibles) at the 6-month following-up assessment. The measurements were performed under both relaxing and maximal clenching positions through three cross sections of the masseter muscle (planes A, B, and C). Plane A contains the line from the mouth angle to the ipsilateral ear lobe. Planes B and C are parallel planes above and below plane A with a distance of 1 cm between them.

RESULTS

No significant difference between the preoperative and postoperative thicknesses of the masseter muscle for planes A and B (p > 0.05) was found, but there was a significant difference (p < 0.05) for plane C. The postoperative thickness of the masseter muscle in plane C was reduced by 0.244 +/- 0.121 cm in the relaxing position and by 0.244 +/- 0.142 cm in the clenching position, which were respectively 19.22% +/- 7.785% and 15.404% +/- 7.648% of its original thickness. There was no significant difference in the contraction amplitude of the masseter muscle under maximal clenching (p > 0.05) for any of the three cross sections postoperatively.

CONCLUSIONS

The masseter muscle around the mandibular angle becomes atrophied but without functional defect after curved osteotomy. Patients with prominent mandibular angles can be treated simply with curved osteotomy instead of masseter excision.

Malignant fibrous histiocytoma of the bucca: a case report

Malignant fibrous histiocytoma (MFH) is the most common soft-tissue sarcoma, but is relatively uncommon in head and neck area. Histologically, it is difficult to distinguish this tumor from other sarcomas and carcinomas. Surgery is the most reliable treatment for MFH, but the 5-year survival rate for cases of this tumor in the head and neck is low in comparison with MFH of the extremities and trunk. In the case reported here, the patient was a 61-year-old man who presented with swelling and pain of the left bucca. A CT scan demonstrated a 2.5 cm x 5.0 cm inhomogeneous lesion. In MRI, the tumor displayed an inhomogeneous isointense signal on T1-weighted images and a high-intensity signal on T2-weighted images. Fine-needle aspiration (FNA) was performed twice but we were unable to reach a definitive diagnosis histologically. MFH was subsequently diagnosed by open biopsy, and external radiotherapy with 38 Gy of radiation was performed. However, the tumor enlarged after this therapy, and therefore CyberKnife therapy was performed twice, after which the tumor gradually reduced in size. The patient is alive after a follow-up period of 22 months, and therefore we suggest that CyberKnife treatment may be useful for head and neck MFH.

Bipaddled radial forearm flap for the reconstruction of bilateral buccal defects in oral submucous fibrosis

Oral submucous fibrosis can result in progressive closure of the mouth. A total of 10 patients with advanced oral submucous fibrosis were surgically treated. The procedure consisted of (1) release of all the intraoral fibrotic tissue, (2) masticatory muscle myotomy and coronoidotomy, and (3) reconstruction with a bipaddled radial forearm flap. Preoperative mouth opening was 0-5mm (mean 2.3mm). The intraoperative mouth opening was 12-20mm (mean 16 mm) after submucous release, and 32-42 mm (mean 35.5mm) after further release via myotomy and coronoidotomy. The proximal flap included one perforator in four patients and two perforators in the remaining six patients. The flaps were 8-9 cm in length and 2-2.5 cm in width. Nine flaps survived uneventfully. Arterial thrombosis was noted in one flap, which was successfully salvaged. Temporomandibular joint subluxation developed in one patient. Two patients needed flap revision due to bulkiness. The postoperative mouth opening was 18-38 mm (mean 28.2mm) after a mean of 21 months' follow-up, and the mean increase was 25.9 mm. A bipaddled radial forearm flap, using a single donor site, can cover two separate buccal defects after release of oral submucosal fibrosis and obviate the need for a second free flap.

Ectopic bone formation as a complication of surgical rehabilitation in patients with Moebius’ syndrome

PURPOSE

Treatment of facial paralysis by muscular neurotization resulted in ectopic ossification in 1 of 134 cases in this department. That patient suffering from Moebius syndrome (MS) is presented. Reviewing the literature concerning MS, Hox genes and bone morphogenetic protein dysregulation, a pathogenesis of ossification in MS is suggested.

PATIENT

The MS patient exhibited a congenital facial nerve palsy, which was treated by muscular neurotization (Lexer-Rosenthal). Because of postoperative ossification of scarred areas, osteotomy of the processus muscularis and mobilization of the masseter muscle was performed. Nevertheless, further ossification occurred at the interface between the mandible and zygoma and in two masticatory muscles. So, the construction of a neoarthrosis became necessary. Three years later, the iatrogenic bone defect had reossified despite of an active opening therapy.

CONCLUSIONS

Ectopic ossification after muscular neurotization seems to be restricted to patients with MS and is triggered by trauma. Molecular pathogenesis: facial malformations in MS are caused by disturbances in embryonic patterning. Failure in the development of the second pharyngeal arch leads to a spatial BMP-4 dysregulation responsible for ossification after wounding of muscle fascia. Therefore, surgical rehabilitation of facial function by muscular neurotization is contra indicated in MS patients.

The influence of masseter activity on rat mandibular growth

Many studies have shown that mandibular and condylar growth is affected by compressive forces on mandibular bone and the condyle. It has been reported that chondroblastic differentiation and proliferation in chondrocytes play important roles in condylar growth. However, the influence of reduced compressive force on chondroblastic proliferation and mandibular bone formation is not fully understood. Thirty-six 3-week-old male Wistar rats were used in this study. In the experimental group, the masseter muscles were bilaterally resected to evaluate the influence of masticatory force on mandibular and condylar bone morphology. Six weeks after the operation, while the rats were in the pubertal growth stage, lateral X-rays were taken to analyze the skeletal pattern of the mandible. The form of the condyle and the thickness of the chondroblastic layers were evaluated by toluidine blue staining. Chondroblastic proliferation was identified by insulin-like growth factor-1 receptor (IGF-1r) immunostaining and bone resorption of the condyle was assessed by measuring tartrate-resistant acid phosphatase (TRAP) activity. Lateral X-rays of the mandible showed that rats in the experimental group tended to have large mandibular plane angles. The chondroblastic layer in the condyles of the experimental group rats was thinner than in the control group. The expression of IGF-1r immunopositive cells in the experimental group was significantly lower than in the control chondrocytes, and the number of TRAP-positive cells was significantly higher in the condylar bone of the experimental group. We conclude that masseter muscle activity is closely related to mandibular morphology during growth.

[Plastic surgery in patients with facial palsy]

In short-term irreversible paralysis caused by facial nerve problems the aim is to re-innervate the paralysed facial musculature. Whenever a paralysis remains untreated for longer than 12-18 months successful re-innervation is unlikely. In longer-term paralysis the symmetry of the face at rest can be restored by a static procedure, a skin resection or a fascial suspension for example. Restoration of movement in the paralysed side of the face is possible by means of a dynamic procedure. For many years the temporal muscle and the masseter muscle have been used to improve the position of the mouth and closure of the eye. Spontaneous laughter can again be made possible by using a muscle from elsewhere in the body (e.g. the gracilis or possibly pectoralis minor) and attaching it to the nerve supply of the opposite side of the face.

An unrecognized foreign body in the parotid gland after trauma

OBJECTIVE

Foreign bodies within the parotid gland retained after trauma are rarely observed, due in part to ease of detection. Few, however, particularly wooden foreign bodies, may not be identified clinically and radiologically.

CASE

A 44-year-old male was admitted complaining of recurrent swelling and pain in the left parotid gland with recent history of penetrating parotid trauma and foreign body removal. Ultrasonography revealed a high degree of parenchymal heterogeneity and an 18 x 5.7 mm linear mass shadow. Following superficial parotidectomy, an approximately 1 x 2 cm wooden fragment that was buried in the masseter muscle and surrounded by granulation tissue was palpated and extracted.

CONCLUSION

Any suspicion of a residual foreign body after penetrating parotid gland trauma can be clarified with a detailed radiological examination, which may provide further guidance for treatment. The treatment modality of parotid foreign bodies is early surgical exploration, and in delayed cases, superficial parotidectomy may be needed.

Radiofrequency volumetric reduction for masseteric hypertrophy

Masseteric hypertrophy occurs frequently among Asians, including Koreans, because of racial characteristics and dietary habits. It is thought to be an unpleasant feature, especially because of its strong and masculine impression. Recently, the authors developed a method for the volumetric reduction of hypertrophied masseter muscles using radiofrequency energy to correct the squared facial appearance caused by the hypertrophy. This study was performed to investigate the effects of radiofrequency applied to reduce hypertrophied masseter muscles of patients who sought an aesthetic alternative for a slim, smooth, and feminine-looking lower facial contour. A total of 340 patients were treated. The patients usually recognized the volume change 3 to 6 weeks after treatment, and an objective volume reduction was observed within 3 months of the operation. The range of the reduction in the masseter thickness, as measured by ultrasonic examination at a 6-month postoperative follow-up visit, was 10% to 60% (mean, 27%). Most of the patients could eat a nearly normal diet after 4 weeks and were satisfied with the improved aesthetic contour lines of their lower face. Radiofrequency-induced coagulation tissue necrosis of the masseter did not cause any infections or limitations of mouth opening, and the clinical improvement was well maintained after the treatment.

Structural fat grafting: more than a permanent filler

Grafted fat has many attributes of an ideal filler, but the results, like those of any procedure, are technique dependent. Fat grafting remains shrouded in the stigma of variable results experienced by most plastic surgeons when they first graft fat. However, many who originally reported failure eventually report success after altering their methods of harvesting, refinement, and placement. Many surgeons have refined their techniques to obtain long-term survival and volume replacement with grafted fat. They have observed that transplanted fat not only adjusts facial and body proportion but also improves surrounding tissues into which the fat is placed. They have noted not only the improvement in the quality of aging skin and scars but also a remarkable improvement in conditions such as radiation damage, chronic ulceration, breast capsular contracture, and damaged vocal cords. The mechanism of fat graft survival is not clear, and the role of adipose-derived stem cells and preadipocytes in fat survival remains to be determined. Early research has indicated the possible involvement of more undifferentiated cells in some of the observed effects of fat grafting on surrounding tissues. Of particular interest is the research that has pointed to the use of stem cells to repair and even to become bone, cartilage, muscle, blood vessels, nerves, and skin. Further studies are essential to understand grafted fat tissue.

Nodular fasciitis in the orofacial region

Nodular fasciitis (NF) is a benign, reactive proliferation of fibroblasts in subcutaneous tissues which commonly occurs in the deep fascia. It can only be diagnosed by histopathological examination of a biopsy. A total of 23 orofacial NF patients was analysed, including those reported in the English language literature and six new patients from the files of this hospital. All patients were treated between 1994 and 2005. The reported lesions were located in cheek masseter muscle, parotid gland, upper neck, upper gingiva and body of mandibular. The clinical and histological features and differential diagnoses are discussed. All lesions were removed under general or local anaesthesia and no recurrence of the lesions was found.

A comparison of commissure excursion following gracilis muscle transplantation for facial paralysis using a cross-face nerve graft versus the motor nerve to the masseter nerve

BACKGROUND

The microneurovascular transfer of a free muscle transplant is the procedure of choice for facial animation in a child with facial paralysis. One of the critical factors of this procedure is the selection of a motor nerve to innervate the transplanted muscle.

METHODS

From 1989 to 1999, 166 free segmental gracilis muscle transfers were performed in 121 children for facial animation. The cross-face nerve graft was used in 70 procedures (cross-face nerve graft group) to innervate the muscle by branches of the seventh nerve for the normal side. The ipsilateral masseteric nerve was used in 94 procedures (50 patients, masseter group) and the ipsilateral accessory nerve was used in two procedures (one patient). To compare the operative procedures between the first two groups, all charts were reviewed. The extent of oral commissure movement was determined by measurements taken from the tragion to the oral commissure, both at rest and with full smile. In the cross-face nerve graft group (n = 20), the extents were measured on both the normal side and the reconstructed side; in the masseter group (n = 16), they were measured on the left and right sides.

RESULTS

No significant difference was found between the two groups (p < 0.05) for the mean age at the time of muscle transplantation, for the total operation time for muscle transplantation, and for the length of the muscle used or for the fraction of circumference of the segment of gracilis muscle used. Although the operative variables were similar between two groups, the muscle excursion differed. Excursion in the cross-face nerve graft group was less than that on the right (p = 0.0006) or left (p = 0.0000) in the masseter group. It was also less than on the normal side (p = 0.0000) of the cross-face nerve graft group. Also, there was no significant difference between the left and right sides within the masseter group (p < 0.05). Furthermore, the extent of oral commissure movement in the masseter group was similar to that of the normal side in the cross-face nerve graft group (p = 0.35, p = 0.61).

CONCLUSION

These results indicate that segmental gracilis muscle transplantation using the motor nerve to the masseter nerve for facial animation in children is a very reproducible operation and provides a commissure excursion in the range of normal.

Reconstruction of #7 facial cleft with distraction-assisted in situ osteogenesis (DISO): role of recombinant human bone morphogenetic protein-2 with Helistat-activated collagen implant

A case involving concomitant presentation of a #7 lateral facial cleft with a complete cleft of the ipsilateral lip, alveolus, and palate is presented. The mandibular defect was Pruzansky III with a foreshortened body, absent ramus and absent masseter. Taking advantage of developmental field theory, reconstruction of the osseous defect was undertaken using the autogenous periosteum as a source of mesenchymal stem cells. Expansion of the periosteum was followed by implantation of Helistat (Integra Life Sciences, Plainsboro, NJ) collagen sponge saturated with recombinant human bone morphogenetic protein-2. Stimulation of this distraction-induced envelope by rhBMP-2 resulted in abundant production of bicortical membranous bone in situ within 12 weeks. The neoramus was subsequently suspended from the cranial base, and a temporalis muscle transfer was used to provide motor control of the jaw. Synthesis of bone in this manner is termed DISO (distraction-assisted in situ osteogenesis). The biologic rationale and clinical implications of DISO are discussed.

An impact of masticatory muscle function on IL-1beta and SOX9 expression in condyle

The importance of masticatory muscle function on the growth and differentiation of condyle was examined. The aim of this study was to investigate how reduced masticatory muscle function influences intrinsic regulatory factors which govern growth and differentiation of condylar cartilage. Masseter muscles of 3-week-old Wistar rats were resected bilaterally. Masseteric resected animals and corresponding control animals were sacrificed at 3, 6, 12 and 21 days post-resection. The condyles were then processed for histological and immunohistochemical analysis. The expression patterns of an inhibitory regulator (IL-1beta) and a master regulator (Sox9) of chondrogenesis in condylar cartilage of growing rats were investigated. Quantitative analysis shows that masseteric resection significantly increased the number of IL-1beta positive cells in proliferative layer. In contrast, the number of Sox9 positive cells was significantly decreased compared to the control animals. It can be concluded that the reduced articular function due to masseteric resection decreased condylar cartilage cell differentiation which led to the decrease in the thickness of condylar cartilage.

The role of imaging and surgery in the management of vascular tumors of the masseter muscle

PURPOSE

Intramuscular vascular malformations are uncommon lesions in the head and neck that may mimic salivary gland disease. This study reports on the use of various imaging modalities and recommends a surgical approach in the management of vascular malformations of the masseter muscle.

PATIENTS AND METHODS

This is a retrospective study of 7 consecutive patients with vascular tumors of the masseter muscle treated in one unit between 1995 and 2004. The age, gender, signs and symptoms, imaging methods, and surgical outcome are reported. A previously unreported surgical approach is described.

RESULTS

All patients had atypical swellings in and around the parotid region that were difficult to diagnose on plain radiography and computed tomography. Magnetic resonance imaging provides accurate three-dimensional images and provisional diagnosis of lesions within the masseter muscle. Six of the 7 patients underwent surgery by the recommended approach. No patients developed permanent facial weakness following modified parotidectomy. No recurrence of the vascular tumors occurred when the recommended approach is used.

CONCLUSIONS

Magnetic resonance imaging remains the imaging modality of choice for the management of tumors of the masseter muscle. The extended parotidectomy approach gives good and safe surgical access in the management of these uncommon lesions.

Transmasseteric antero-parotid approach for open reduction and internal fixation of condylar fractures

The morbidity that results from surgical approaches to the condylar neck, and the time-consuming nature of the operation inhibits many surgeons from using open reduction and internal fixation for the treatment of condylar fractures. The many approaches that have been described stand testimony to the disadvantages of the individual techniques. The most common problems are limited access and injury to the facial nerve. We describe the transmasseteric antero-parotid (TMAP) technique, which offers swift access to the condylar neck while substantially reducing the risk to the facial nerve and eliminating the complications associated with transparotid approaches.

Selective Neurectomy of the Masseteric Nerve in Masseter Hypertrophy

Asian women prefer to have more delicate and feminine features rather than prominent squared mandibular angles. It was proposed that a selective neurectomy of the masseteric nerve might result in muscular atrophy and subsequent reduction of the hypertrophic mass of the masseter muscle. This study is aimed at an elucidation of the precise course of the masseteric nerve and the impact of a neurectomy in case of masseter hypertrophy. Eleven heads of Korean cadavers were halved and dissected. The masseteric nerve and artery in the mandibular notch were clearly located. A selective neurectomy of the masseteric nerve was performed in four cases of masseter hypertrophy. The masseteric nerve and artery behind the temporalis muscle at the mandibular notch cross over to the masseter. The masseteric nerve was found 11.3 +/- 2.6 mm horizontally from the anterior border of the ramus and 11.3 +/- 2.6 mm above the mandibular notch and the superior masseteric artery, 25.6 +/- 3.7 mm from the ramus, and 7.8 +/- 2.6 mm above the notch. A neurectomy of the masseteric nerve can be used to reduce the hypertrophied masseter and as an ancillary procedure of mandibular angle ostectomy. One procedure can accompany another in the reduction of a prominent mandibular angle.

Endoscopic vertical ramus osteotomy: early clinical results

PURPOSE

The benefits of minimally invasive surgery have been well documented. The purpose of this report was to present early results in a series of patients who had endoscopic mandibular orthognathic surgery. Patients and methods This is a retrospective evaluation of 14 patients who underwent endoscopic vertical ramus osteotomy and rigid fixation for the treatment of mandibular prognathism (n = 9), malocclusion secondary to trauma (n = 3), or other pathology (n = 2). A 1.5-cm incision was made directly below the mandibular angle. The dissection was continued bluntly to the masseter muscle, which was incised using a needlepoint electrocautery. Then, with endoscopic elevators, an optical cavity was created for insertion of a Hopkins endoscope and visualization of the ramus/condyle unit. Anatomic landmarks were identified and the operation carried out with specially designed endoscopic equipment. Preoperative (T0), postoperative (T1), and follow-up (T2) clinical examinations; lateral cephalograms; and panoramic radiographs were used to evaluate the outcomes.

RESULTS

The procedures performed included: vertical ramus osteotomy (n = 13 patients, 23 sides) and condylectomy plus vertical ramus osteotomy (n = 1 patient, 1 side). Mean operating time was 37 minutes per side. One patient had temporary marginal mandibular nerve weakness. The occlusal result was as planned in all cases. Panoramic radiographs documented postoperative ramus/condyle unit position and lateral cephalograms documented mandibular position.

CONCLUSIONS

The results of this case series indicate that endoscopic vertical ramus osteotomy with rigid fixation is feasible for correction of a variety of mandibular deformities.

Paralyzed masseter muscle reinnervation by facial nerve implantation or anastomosis: a comparative study in rabbits

OBJECTIVE

To investigate the changes in the physiological and structural properties of the masseter muscle after reinnervation through different reinnervation methods.

METHOD

Twenty-four adult rabbits were randomly divided into groups A and B (n=12) after the establishment of masseter muscle paralysis, followed by facial nerve anastomosis with the masseteric nerves in group A and facial nerve implantation into the masseter muscle in group B. At 1, 3 and 6 months after the operation, gross observation and wet weight measurement of the muscles were conducted along with myoelectric activity and enzyme- histochemical analyses and ultrastructural observation as well.

RESULTS

The reinnervation of the masseter muscle by both facial nerve anastomosis and implantation was confirmed and the muscles recovered their motion of contraction activity. Changes took place in the histochemical types of the muscle fibers, which tended to assume the properties typical of facial muscles. Three months after the operation, the muscle fiber conduction velocity recovery after the reinnervation by the two methods was significantly different (P<0.01), but not so till 6 months postoperatively (P>0.05).

CONCLUSION

This two methods are both effective in the reinnervation of the muscles, but in one-stage operation, intramuscular nerve implantation is relatively less complicated in operation and causes less damage while producing similar effects to that by nerve anastomosis.

[Expression of collagens in reattached masseter muscles to mandibles following a surgical detachment]

OBJECTIVE

The aim of this study was to investigate the expression of collagen in the process of masseter muscle reattachment to the cortical and cancellous bones of mandible.

METHODS

A total of nine adult goats were used in the study. One was the control. The other eight were treated with bilateral detachment of the masseter muscles. The biopsies of bone and muscle were taken at 2, 4, 8 and 12 weeks after the operation. The characteristics of the healing muscle-bone interfaces were examined using immunohistochemical techniques.

RESULTS

Immunohistochemical analysis illustrated that the locations of collagen type I, II and III were different during the healing process, but similar in the cortical and cancellous bones.

CONCLUSION

This study demonstrates that the distribution of the three types of collagens at the muscle-bone interfaces is associated with time, but not related with their locations.

False diagnosis caused by Warthin tumor of the parotid gland combined with actinomycosis

A case is reported in which a unilateral parotid gland cystadenolymphoma was combined with actinomycosis. A 48-year-old woman presented with a mass in the left parotid region and paresis of the lower left palpebra. The computed tomography, echography, and parotid radiographic findings did not exclude a neoplasm of the left parotid gland. The ramus of the mandible was involved in the process. Intraoperative freezing histology, total parotidectomy, and partial mandibulectomy were performed, with sacrifice of the facial nerve followed by nerve reconstruction. The final histological evaluation was Warthin tumor with actinomycosis. Four years after treatment, the patient is free of disease. No similar cases seem to have been reported thus far.

Intraoperative ultrasound imaging to aid abscess drainage--a technical note

Diagnostic ultrasound is used widely to identify the presence of fluid collections preoperatively. Although its role in other parts of the body is well established, this report describes the technique of using diagnostic ultrasound intraoperatively to aid drainage of a large fascial space abscess in the head and neck. Following previously inadequate drainage of a large superficial abscess from a blindly placed drain, a second procedure was carried out, using ultrasound imaging to locate the persisting abscess. Furthermore, ultrasound demonstrated the adequacy of drainage and helped the surgeon to position the drain in the correct tissue space. We consider that intraoperative use of ultrasound has a role as a guidance tool to drain superficial fascial space abscesses in the head and neck region.

A transparotid transcutaneous approach for internal rigid fixation in condylar fractures

Closed versus open reduction in condyle fractures is a dilemma that may torment the plastic surgeon. Although at present it is accepted that there are fractures that must be open reduced as when the middle cranial fossa or temporal fossa are involucrated, foreign body are in the joint capsule, lateral extracapsular deviation of condylar deviation, and open fractures. Risdon or retromandibular approaches are used for the treatment of fractures in the condyle neck and superior third of the lower ramus.When both approaches are used the correct placement of screws is very difficult for the following reasons: 1. Both drill and screwdrivers must be placed in an oblique direction to the bone surface; as a result, screws do not press the plate toward the bone and therefore a deficient stabilization results; 2. A distraction of too much soft tissue entrapped between the skin and mandibular bone is necessary for a good visual to surgical field and 3. The parotid tissue, the masseter muscle, and the facial nerve must be strongly distracted facilitating the nerve injury.A transcutaneous transparotid approach is the most appropriate for screws placement. By means of transbuccal set it is possible to reach the mandibular bone going through both the parotid tissue and the masseter muscle avoiding the injury the branches of the facial nerve.A case report illustrates the practical application of the above technique and it shows that as the lesion of branches of the facial nerve can be avoided.

[Ectopic parotid gland in the mandible and masseter muscle]

An unusual case of double salivary ectopy of parotid gland is described into the masseter muscle and the mandibular ramus in a 45 year-old patient. He first was seen for a slow course tumefaction of the cheek. Imaging demonstrated the intramasseteric localization of the tumefaction and revealed a bone defect in the upper medial part of the mandibular ramus. The intramasseteric salivary ectopy has been confirmed by histologic examination.