A Case Treated With Photoimmunotherapy Under a Navigation System for Recurrent Lesions of the Lateral Pterygoid Muscle.

BACKGROUND: Head and neck photoimmunotherapy specifically destroys tumor cells by irradiating them with 690 nm red light after administering cetuximab sarotalocan sodium. The key point in the technique of photoimmunotherapy is to set the irradiation area precisely with a margin added to the target lesion while securing a safety zone with large vessels such as the internal carotid artery. CASE REPORT: At our Institution, we performed photoimmunotherapy in combination with use of a navigation system on a male patient in his 70s with maxillary gingival carcinoma who had a recurrent lesion deep in the lateral pterygoid muscle. Three months after photoimmunotherapy, the superficial lesion had disappeared, the area of contrast within the lateral pterygoid muscle had improved, and the patient was deemed to have a complete response. CONCLUSION: The Navigation System was successfully used in combination with photoimmunotherapy. Additionally, this allowed the location of the internal carotid artery to be confirmed in real time.

Characterization of the pterygomeningeal artery based on branching pattern and muscular distribution.

PURPOSE: The pterygomeningeal (accessory meningeal) artery arises from the middle meningeal or maxillary artery. Although there is the potential that this artery may be wounded by the surgery for the temporomandibular joint disorder, the current state of anatomical knowledge is insufficient. This study investigated the appearance and the branching pattern of this artery as a means to its characterization. METHODS: The pterygomeningeal artery was dissected in 14 cadavers and its branches and their distributions to the muscles inside the mandible were examined. RESULTS: The maxillary artery passed lateral to the lateral pterygoid muscle. The pterygomeningeal artery arose from the middle meningeal or maxillary artery. It ascended anteriorly and coursed medial or lateral to the mandibular nerve. It passed above the pterygospinous ligament and then descended. The ascending trunk gave some lateral branches to the lateral pterygoid muscle. The branches sometimes passed lateral to the mandibular nerve even if the pterygomeningeal artery coursed medial. The descending trunk was divided into middle and medial branches, which supplied the medial pterygoid muscle and the tensor veli palatini, respectively. The pterygomeningeal artery was sometimes equally bifurcate near the origin, and the counterparts passed lateral and medial to the mandibular nerve. The distributions of the medial and lateral counterparts were equivalent to those of the descending trunk and the lateral branches, respectively. CONCLUSION: The pterygomeningeal artery contains three groups of muscular branches, which sometimes appear in a bifurcate form. Their positions relative to the mandibular nerve and the pterygospinous ligament characterize the artery; this information may help to avoid iatrogenic injury.

Trifurcated external carotid artery and complete gamma-loop of its maxillary branch.

The external carotid artery (ECA) normally bifurcates terminally with the superficial temporal artery (STA) and the maxillary artery (MA). From the horizontally coursing, mandibular segment of the MA leaves the middle meningeal artery (MMA). We hereby report a previously unknown anatomic possibility, incidentally found during an angio-CT scan in an adult female patient. Unilaterally, the ECA was terminally trifurcated, sending off the MA, STA, and MMA. On that side, the mandibular segment of the MA had a gamma-loop and the contralateral one had a U-loop; both these loops were inferior to the lateral pterygoid muscle, closely approaching the respective lingula of the mandible. These findings are relevant during surgery of the parotid gland and infratemporal fossa, approaches of the MMA, and inferior alveolar nerve blocks. The modified origin of the MMA could be explained by an altered development of the primitive stapedial artery.

Metabolic and vascular pattern in medial pterygoid muscle is altered by chronic stress in an animal model of hypodontia.

Psychological stress is an important perpetuating, worsening and risk factor for temporomandibular disorders of muscular or articular origin. Occlusion instability, by the way, is considered a risk factor of this pathology and can be reproduced in some experimental animal models. The exact physiologic mechanism underlying these relations however, remains unclear. Our purpose was to test the hypothesis that chronic stress and unilateral exodontia induce metabolic and vascular changes in the medial pterygoid muscle of rats. Adult Wistar rats were submitted to chronic unpredictable stress and/or unilateral exodontia and their plasma and medial pterygoid muscle were removed for analysis. The parameters evaluated included plasma levels of corticosterone, metabolic activity by succinate dehydrogenase, oxidative capacity by nicotinamide adenine dinucleotide diaphorase, capillary density by laminin and alfa-CD staining and reactive oxidative species production. Chronic unpredictable stress as an isolated factor, increased oxidative metabolism, capillary density and reactive oxygen species production at medial pterygoid muscle. Conversely, exodontia has a main effect in metabolism, promoting glycolytic transformation of muscle fibers. Association of both factors induced a major glycolytic pattern in muscle and vascular changes. Our findings provide insights into the mechanisms, possibly inducing metabolic and vascular alterations on medial pterygoid muscle of rats, by which chronic stress and occlusal instabilities might be involved as risk factors in the pathophysiology of temporomandibular disorders with muscular components.

Chronic stress effects in contralateral medial pterygoid muscle of rats with occlusion alteration.

Temporomandibular disorder (TMD) has a high prevalence in our society, characterized by a severe pain condition of the masticatory muscles and temporomandibular joint. Despite the indication of multiple factor initiators of TMD, there is still controversy about its etiology and its pathophysiology is poorly understood. Using rats as experimental animals we investigated the effect of unpredictable chronic stress with or without unilateral molar extraction on the contralateral medial pterygoid muscle. Our hypothesis is that these two factors induce changes in morphology, oxidative metabolism and oxidative stress of muscle fibers. Young adult male Wistar rats (±200g) were divided into four groups: a group with extraction and unpredictable chronic stress (E+US); with extraction and without stress (E+C); without extraction and with unpredictable chronic stress (NO+US); and a control group without either extraction or stress (NO+C). The animals were subjected to unilateral extraction of the upper left molars, under intraperitoneal anesthesia with 4% Xylazine (10mg/kg) and 10% Ketamine (80mg/kg) on day zero. The rats of groups E+US and NO+US were submitted to different protocols of stress, from the 14th day after the extraction. The protocols were different every day for five consecutive days, which were repeated from the 6th day for five days more. Contralateral medial pterygoid muscles were obtained on the 24th day after the start of the experiment for morphological, metabolic, capillary density, and oxidative stress analysis. The data from capillary density showed a decrease of capillaries in animals subjected to dental extraction, compared with those without extraction and an increase of laminin expression in the group submitted to the unpredictable chronic stress when compared to the unexposed to stress. SDH test revealed a decrease of light fibers in the group submitted to unilateral extraction of molars, compared with this area in the control group. In E+US and NO+US groups, the deeply stained fibers increased compared to NO+C.·The exodontia factor was able to increase the ROS activity in muscle, whereas the stress factor does not significantly alter ROS in this tissue. It was concluded that both unpredictable chronic stress and the extraction induce metabolic and density of capillary changes in the contralateral medial pterygoid muscle to extraction, suggesting that these factors for a longer period of this experiment could induce muscle damage related to TMD.

Divided maxillary artery in relation to the lateral pterygoid muscle.

We describe an anatomical variation of the right maxillary artery. The variation loops deep, giving off a middle meningeal artery with an extremely short extracranial segment, then bifurcates into unequal branches. The smaller branch passes superficial to the lateral pterygoid head and distributes primarily to the masticatory muscles. The larger partially pierces the lateral pterygoid lower head, re-emerges superficially, branches again and passes into the pterygopalatine fossa. The larger lies superficial to the lingual and inferior alveolar nerves and deep to the buccal nerve. An embryonic development origin of the cranial arteries is suggested.

Piezoelectric osteoarthrectomy for management of ankylosis of the temporomandibular joint.

We describe the use of a piezoelectric osteotome for removal of bone in patients with ankylosis of the temporomandibular joint (TMJ) and its advantages over conventional techniques. We studied 35 patients with ankylosis of 62 TMJ (27 bilateral and 8 unilateral, 2 recurrent) who were treated by gap arthroplasty between 1 January 2011 and 31 December 2012. We used a preauricular, with extended temporal, incision in all cases. The ankylosis was released with a piezoelectric scalpel. There were 23 men and 12 women, mean (SD) age 16 (9) years. We noticed a substantial reduction in bleeding with the piezoelectric bone cutter compared with the dental drill, though the operating time was longer. We noticed no bleeding from the maxillary artery or pterygoid plexus. Mean (SD) bleeding/side was 43 (5) ml, and mean (SD) operating time was 77 (8) minutes for a single joint. At 6 months' follow-up mean (SD) passive mouth opening was 35 (3) mm. Piezoelectric bone removal for the release of ankylosis of the TMJ is associated with minimal bleeding, few postoperative complications, and satisfactory mouth opening at 6 months' follow up.

Microsurgical anatomy of the infratemporal fossa.

The objective of this study is to clearly and precisely describe the topography and contents of the infratemporal fossa. Ten formalin-fixed, adult cadaveric specimens were studied. Twenty infratemporal fossa were dissected and examined using micro-operative techniques with magnifications of 3-40×. Information was obtained about the inter-relationships of the contents of the infratemporal fossa. The infratemporal fossa lies at the boundary of the head and neck, and the intracranial cavity. It is surrounded by the maxillary sinus anteriorly, the mandible laterally, the pterygoid process anteromedially, and the parapharyngeal space posteromedially. It contains the maxillary artery and its branches, the pterygoid muscles, the mandibular nerve, and the pterygoid venous plexus. The course and the anatomic variation of the maxillary artery and the branches of the mandibular nerve were demonstrated. The three-dimensional (3D) relationships between the important bony landmarks and the neurovascular bundles of the infratemporal fossa were also shown. The skull base anatomy of the infratemporal fossa is complex, requiring neurosurgeons and head and neck surgeons to have a precise knowledge of 3D details of the topography and contents of the region. A detailed 3D anatomic knowledge is mandatory to manage benign or malignant lesions involving the infratemporal fossa without significant postoperative complications.

Radiologic assessment of the relationship between the maxillary artery and the lateral pterygoid muscle.

OBJECTIVE: The course of the second part of the maxillary can vary among different races. The aim of this study was to evaluate the relation between the maxillary artery and the lateral pterygoid muscle in a white population sample on computed tomographic (CT) angiograms. MATERIALS AND METHODS: We retrospectively reviewed multidetector CT angiograms of 209 patients (134 men and 75 women). The images were taken using a 64-row multidetector CT scanner. The imaging parameters were 0.5 × 64-mm slice thickness, 0.5- or 0.3-mm increment, 120 kV, 250 mA s, 0.5-second rotation time, 0.641 pitch, and 512 matrix. The relationship between the pterygoid portion of the maxillary artery and the lateral pterygoid muscle was assessed on axial, sagittal, and coronal multiplanar reformatted images with the Vitrea 2 software program. RESULTS: A total of 572 maxillary arteries in 286 patients were assessed. Of these maxillary arteries, 418 (68.42%) had a superficial course to the pterygoid muscle and 132 (31.58%) had a deep course. In 165 (78.94%) of 286 patients, there was a cross-lateral symmetry of the course of the artery; that is, both vessels were superficial or deep. In 44 (21.1%) of 209 patients, an asymmetric course was observed. CONCLUSIONS: Because of the incidence of the asymmetric presentations, generalization regarding such a controversial topic should not be based on findings of cadaveric studies and each hemi head should be considered as a single entity. Therefore, advanced imaging systems are useful tools in preoperative planning and play a key role in the avoidance of hemorrhagic complications.

Percentage of lateral pterygoid muscle inserted in the disc of human temporomandibular joint / Porcentaje del músculo pterigoideo lateral inserto en el disco de la articulación temporomandibular humana

Insertion of the upper head of the lateral pterygoid (UHLP) in the temporomandibular joint disc (TMJ) has been linked to anterior displacement of the disc and temporomandibular disfunction. The aim of this study was to determine in human adults, the percentage of muscle fiber in the upper head of the lateral pterygoid muscle inserted in the articular disc. A systematic review of the literature was designed beginning with articles published in Medline, Lilacs and Scielo data bases between the years 1990 and 2010. Key words "Lateral Pterygoid Muscle" and Pterygoid Lateral Muscle" were used, and the term MeSH "Pterygoid Muscle" with Boolean OR "Lateral Ptrerygoid Muscle" AND "Insertion" and the free terms "Pterygoid Lateral Muscle Disc Articular" and "Pterygoid lateral Muscle Meniscus". Of the 156 articles obtained and analyzed, 18 articles meeting eligibility criteria were selected. Based on those articles the percentage of insertion of the CSPL in the TMJ disc was evaluated, each one was subsequently assigned a level of evidence according to OCEBM Oxford Centre Evidence Based Medicine. Only four articles answered the research inquiry, three studies were histological and one used imaging techniques with cross section slices with an adequate evidence level (1B). However, results differed with insertion percentages from 2 percent to 69.8 percent being reported in the superior head of the lateral pterygoid muscle in the articular disc.

La actividad de la inserción de la cabeza superior del pterigoideo lateral (CSPL) en el disco de la articulación temporomandibular (ATM) ha sido vinculada al desplazamiento anterior del disco y disfunción temporomandibular. El propósito de este estudio fue determinar el porcentaje de fibras musculares de la cabeza superior del músculo pterigoideo lateral que se insertan en el disco articular, en humanos adultos. Se diseñó una revisión sistemática de la literatura a partir de artículos primarios publicados en las bases de datos Medline, Lilacs y Scielo entre los años 1990 y 2010. Se utilizaron las palabras clave "Músculo Pterigoideo Lateral" y "Pterygoid Lateral Muscle", el Término MeSH: "Pterygoid Muscle" con los boleanos OR "Lateral Pterygoid Muscle" AND "Insertion" y los Términos Libres: "Pterygoid Lateral Muscle Disc Articular" y "Pterygoid lateral Muscle Meniscus". Se obtuvieron 156 artículos, los cuales fueron analizados y se seleccionaron 18 que cumplieron con los criterios de elegibilidad. En base a estos artículos se evaluó el porcentaje de inserción de la CSPL en el disco de la ATM, posteriormente a cada uno se les otorgó un nivel de evidencia de acuerdo a la clasificación de Oxford Centre Evidence Based Medicine (OCEBM). Solo 4 artículos respondieron a la pregunta de investigación, 3 estudios fueron histológicos y 1 imagenológico, todos con diseños de cortes transversales con buen nivel de evidencia (1b). Sin embargo los resultados fueron disímiles, reportándose porcentajes de inserción del 2 al 69,8 por ciento de la cabeza superior del pterigoideo lateral en el disco articular.

Anatomical variability of the maxillary artery: findings from 100 Asian cadaveric dissections.

OBJECTIVE: To describe the anatomical variability of the maxillary artery. DESIGN: Anatomical study. SETTING: Academic institution. SUBJECTS: One hundred midsagittal sections of randomly selected adult cadaver heads with intact maxillary sinuses, pterygopalatine fossa, and surrounding structures. MAIN OUTCOME MEASURES: The location of the proximal portion of the maxillary artery in relation to the lateral pterygoid muscle, the branches of the mandibular division of the trigeminal nerve, and the branching patterns of the third section of the maxillary artery. RESULTS: The first and second sections of the maxillary artery most commonly traveled through the lateral aspect of the lateral pterygoid muscle, with the inferior alveolar nerve, lingual nerve, and buccal nerve on the medial side of the maxillary artery (61.0%). The course and branching type of the third section of the maxillary artery were classified into 3 patterns: loop (61.0%), bifurcated (19.0%), and straight (18.0%). In most cases (62.0%), the division point of the maxillary artery was located on the superior and medial thirds of the posterior wall of the maxilla. CONCLUSION: This study provides detailed information concerning the anatomical variability of the maxillary artery, which we hope will help prevent the arterial bleeding that may occur during mandibular or maxillary osteotomy or maxillectomy for ligation of the sphenopalatine artery.

Perforation of the inferior alveolar nerve by the maxillary artery: an anatomical study.

The infratemporal fossa is a clinically important anatomical area for the delivery of local anaesthetic agents in dentistry and maxillofacial surgery. We studied the infratemporal fossas in white cadavers, and in particular the topographical relations of the inferior alveolar nerve and the maxillary artery. In 3 of the 50 fossas dissected the maxillary artery passed through the inferior alveolar nerve, splitting it into superficial and deep divisions. Entrapment of the maxillary artery may cause numbness or headache and may interfere with injection of local anaesthetics into the infratemporal fossa.

Clinical implications of the topography of the arteries supplying the medial pterygoid muscle.

The literature contains numerous accounts of the muscular anatomy of the medial pterygoid muscle, but little is known about the detailed vascular supply of the muscle. Numerous surgical procedures, such as mandibular ramus osteotomy, angle reduction, and/or parotidectomy, are performed around the muscle in the absence of this information. This study aimed to clarify the arterial supplies to the medial pterygoid muscle to provide critical information for use during various surgical procedures. Detailed dissections were performed on 20 sides of adult cadaveric head and neck specimens after injecting the carotid artery with red liquid neoprene latex. The medial pterygoid muscle was supplied by the following 5 branches of the external carotid artery: (1) the pterygoid artery of the maxillary artery, (2) a direct muscular branch of the facial artery, (3) the ascending palatine artery, (4) an anterior muscular branch of the facial artery, and (5) a previously undescribed muscular branch of the external carotid artery. This analysis of vascular anatomy has revealed new anatomic information on the blood supplies to the medial pterygoid muscle and will be useful to the development of guidelines for preventing hemorrhage during surgical procedures.

Traumatic arteriovenous malformation following maxillary Le Fort I osteotomy.

OBJECTIVE: Complications following maxillary Le Fort I osteotomy are rare. The authors present the rare complication of an arteriovenous malformation following such a procedure in a 25-year-old woman with a cleft lip and palate that was treated successfully with radiologically guided embolization.

Morphological and histological effects on the medial pterygoid muscle after unilateral exodontia in gerbils.

Morphological effects on the medial pterygoid muscle were evaluated in 20 male gerbils (average weight, 55 g) after occlusal alterations induced by extraction of left side molar teeth. Controls were only submitted to surgical stress. Sixty days after surgery, the groups were divided into two subgroups for the following studies: (1) observation of macroscopic morphology and vessels distribution (n=10); (2) light microscopy histological analysis (n=10). Group results were statistically compared using the Wilcoxon and Mann-Whitney tests, with a significant value of p<0.05. Statistical differences in biometric data were found between the left and right sides of the experimental group (p=0.043), and between the left side of the control group when compared to the same side in the experimental group (p=0.044). Vessels supplied by bundles of the external carotid artery in the medial pterygoid muscle did not show distribution differences in group comparisons. Histological alterations were found in the ipsilateral side of the experimental group, with a central localization of the nucleus and degenerative aspect of the fibers, usually near to internal aponeurosis. Fiber diameters seemed reduced and the neuromuscular spindles were localized near internal aponeurosis and had a modified appearance. It is concluded that the medial pterygoid muscle in the gerbil is sensitive to alterations of the masticatory movements.

Optimizing exposure of the posterolateral maxillary and pterygoid region: the lower cheek flap.

AIM: Description of an alternative surgical approach to the posterolateral maxillary and pterygoid region. PATIENTS AND METHOD: Three patients with posterior maxillary/pterygoid lesions are described in whom a lower cheek flap was used to achieve optimal surgical exposure. After midline division of the soft tissues of the lower lip and chin, the incision is extended posteriorly in the inferior gingivobuccal sulcus and continued lateral from the retromolar trigone in the upward direction lateral from the maxillary tuberosity. The flap is elevated under the periosteum towards the angle of the mandible with detachment of the masseter muscle. By marginal resection of the anterior part of the ascending mandible, visualisation of the posterolateral maxillary and pterygoid region can be optimized. CONCLUSION: As compared to the transoral approach, the lower cheek flap creates an optimal surgical exposure of the posterolateral maxillary sinus wall and pterygoid plates and should be considered for maxillary lesions extending into the pterygoid plate and pterygoid muscles.

Ultrastructural and biochemical changes of the medial pterygoid muscle induced by unilateral exodontia.

The aim of the present study was to investigate the histological, biochemical and ultrastructural effects of occlusal alteration induced by unilateral exodontia on medial pterygoid muscle in guinea pigs, Cavia porcellus. Thirty (n=30) male guinea pigs (450g) were divided into two groups: experimental-animals submitted to exodontia of the left upper molars, and sham-operated were used as control. The duration of the experimental period was 60 days. Medial pterygoid muscles from ipsilateral and contralateral side were analyzed by histological (n=10), histochemical (n=10), and ultrastructural (n=10) methods. The data were submitted to statistical analysis. When the ipsilateral side was compared to the control group, it showed a significantly shorter neuromuscular spindle length (P<0.05), lower oxidative metabolic activity, and microvessel constriction, in spite of the capillary volume and surface density were not significantly different (P>0.05). In the contralateral side, the neuromuscular spindles showed significantly shorter length (P<0.05), the fibers reflected a higher oxidative capacity, the blood capillaries showed endothelial cell emitting slender sprouting along the pre-existing capillary, and significantly higher blood capillary surface density, and volume density (V(v)=89% Mann-Whitney test, P<0.05). This finding indicated a complex morphological and functional medial pterygoid muscle adaptation to occlusal alteration in this experimental model. Considering that neuromuscular spindles are responsible for the control of mandibular positioning and movements, the professional should consider if these changes interfere in the success of clinical procedures in medical field involving stomatognathic structures.

Involvement of pterygoid venous plexus in patulous eustachian tube symptoms.

CONCLUSIONS: The pterygoid venous plexus (PVP) is an important factor in the mechanism of eustachian tube (ET) closure under conditions that can cause increased venous pressure in the head, such as during neck compression and postural change from the sitting/standing to the recumbent position. OBJECTIVES: The symptoms of patulous ET are usually improved by neck compression or postural change (from sitting/standing to recumbent position). Venous congestion around the ET and/or gravitational change may be involved in the changing degree of symptoms, but its mechanism is not understood. This study investigated whether the PVP is involved. MATERIALS AND METHODS: The dimensions of soft tissues surrounding ET were measured on magnetic resonance images before and after neck compression. RESULTS: The lateral pterygoid muscle became enlarged after neck compression. Simultaneously, the volume of venous plexus observed between the medial pterygoid muscle and tensor veli palatini muscle was increased. Such enlargement was probably due to blood pooling in the PVP, resulting in protrusion of the ET anterior wall to the luminal side, and decreased ET patency.