RESUMEN

INTRODUCTION: Soft tissue injuries are known complications of orthodontic treatment. Most of the injuries are mild, but severe complications can arise from deeper penetration or dislodgement of brackets and other foreign bodies into the surrounding tissues of the oropharynx and infratemporal fossa. PATIENT CONCERNS: The patient, accompanied by his parents, presented to the Children's Emergency Department with the concern of gradual limitation of mouth opening and eventual trismus, which occurred over a span of 2 weeks. CLINICAL FINDINGS: The patient presented with trismus and slight discomfort at the left cheek region. He reported a history of gradual limitation to his mouth opening 2 weeks prior. He was wearing upper and lower fixed orthodontic appliances and the left distal end of the maxillary archwire was found to have migrated into the left infratemporal fossa. PRIMARY DIAGNOSES: Left medial pterygoid muscle inflammation, or bleeding and haematoma formation, or infection within the infratemporal region. INTERVENTIONS: The maxillary archwire was removed in the Children's Emergency Department and a computed tomography (CT) scan performed subsequently confirmed the diagnosis of left medial pterygoid muscle inflammation. The patient was started on an intravenous (IV) antibiotic and a 2-day course of IV dexamethasone to reduce the muscle inflammation. OUTCOME: By the second day, the patient was able to achieve a mouth opening of 6 mm, and by the second week, the mouth opening had returned to normal. CONCLUSION: The potential risk of soft tissue injury and complications from orthodontic treatment is generally mild and limited. Soft tissue injuries can be avoided with careful management by the operator with the proper precautions taken. Clinicians should be familiar with the surrounding soft tissue anatomy and be aware of the potential for more severe complications and provide management or referral to the appropriate specialty accordingly.

RESUMEN

INTRODUCTION: Temporomandibular disorders (TMD) may include conditions involving the temporomandibular joint and/or masticatory muscles. Approximately 20 % of patients are refractory to first-line therapies. This study aims to evaluate the effects and safety of incobotulinumtoxinA in the treatment of refractory TMD due to disk dislocation. MATERIAL AND METHODS: A quasi-experimental one-arm prospective study was conducted. Target population included individuals with a diagnosis of TMD due to disk dislocation. Patients were treated with electromyography or ultrasound guided injection of incobotulinumtoxinA in the masticatory muscles (20 U into each masseter and pterygoideus lateralis). Pain was assessed using the pain numerical rating scale, maximum unassisted mouth opening was measured in mm, and adverse events were registered at baseline, week 4, week 12 and week 24 post-treatment. Statistical analysis used the Wilcoxon test for the comparison of paired samples and the Mann-Whitney U test for independent samples, considering a p-value ≤ 0.05 as significant. RESULTS: 51 patients with 75 painful temporomandibular joints due to disk dislocation (38 with reduction and 37 without) were included. A significant reduction in pain from a pre-treatment mean of 6.08/10 to a post-treatment mean of 2.04/10 (week 4), 3.18/10 (week 12), and 3.65/10 (week 24) was observed (p < 0.001). A significant decrease in maximum unassisted mouth opening from a pre-treatment mean of 36.45 mm to a post-treatment mean of 32.29 mm at week 4 was observed (p < 0.001). DISCUSSION: Botulinum toxin injection of the masticatory muscles is safe and seems equally effective in reducing pain in patients with refractory TMD due to disk dislocation.

Asunto(s)

RESUMEN

Objectives: Botulinum toxin type A (BTX), a powerful neurotoxin, can be an effective treatment choice for diverse muscular disorders and can reduce abnormal muscle activities. Abnormal movements of the mandible can be caused by involuntary and uncontrolled contractions of the lateral pterygoid muscle (LP) in various pathological situations. Previous reports have shown that BTX can reduce abnormal contractions of the LP. However, needle placement into the LP for BTX injection requires skill, experience, and sufficient anatomical knowledge. To place the needle precisely into the LP, ultrasonography (USG) can be used as an effective needle-guidance modality. USG is a non-invasive imaging modality able to create real-time images without any potential risks, including radiation exposure. Patients and. Methods: The patients who had been performed USG-guided BTX injection into the LP using an intraoral approach were included in this study with a literature review and case presentations. Using the USG, four patients received BTX injections to treat recurrent temporomandibular dislocation and oromandibular dystonia resulting from involuntary LP activity. Result: Involuntary movements of the mandible were improved successfully in all patients, and showed satisfactory results without significant complication. Conclusion: The intraoral approach could prevent potential complications during needle placement. USG-guided BTX injection is an effective, convenient, and safe method that provides real-time imaging without unnecessary pain to the patient.

RESUMEN

BACKGROUND: Botulinum toxin has proven effective in treating persistent myogenous temporomandibular disorders (M-TMDs) unresponsive to conservative therapies. While the usual injection sites are the masseter and temporalis muscles, the deeper lateral pterygoid muscle (LPM) is often overlooked due to its difficulty of access and the risk of local complications. This study aims to evaluate the effectiveness of botulinum toxin-A injections (BTX-A) in the LPM with MR-guided navigation of patients with persistent M-TMDs. METHODS: This retrospective study enrolled 34 patients suffering from M-TMDs despite conservative therapies with a total of 51 injection sessions. All of them were treated by BTX-A injections in the LPM using MR-guided navigation, masseter and temporalis with clinical guidance. The effectiveness of the treatment was evaluated with measures of maximum pain-intensity scores of breakthrough and background pain, maximal interincisal mouth opening (MIO), and the presence of joint sounds. The assessment was conducted before injections, and subsequently, at 1 and 3 months postoperatively. Adverse events and perception of improvement with the treatment were also reported for each injection sessions. RESULTS: BTX-A injections in the LPM significantly improved pain scores intensity with a reduction of 65 % and 49 % respectively at the 1- and 3-month follow-ups, with peak effectiveness at 1 month. This study showed also a statistically significant improvement in mean MIO at 3 months post-injection and a decrease in joint sounds with persistence in 9,7 % of cases at 3-month follow-up compared to 41,2 % at baseline. No significant adverse events were observed. Patients treated with BTX-A injections in the LPM had a subjective complete improvement in their perception of treatment efficacy in 63 % of cases at the end of the follow-up period. CONCLUSIONS: This study reports clinical experience on the use of MR-guided navigation to perform accurate, reliable, and safe BTX-A injections in the LPM. Although our results appear to be encouraging regarding symptom improvement of patients suffering from persistent M-TMDs, this approach may not be feasible as a primary standard procedure for managing M-TMDs. Further research is necessary to explore potential reproducible, safe, and cost-effective alternatives to enhance the accessibility of the LPM in clinical practice.

RESUMEN

OBJECTIVES: To test the hypotheses that (a) the force thresholds at onset of medial pterygoid muscle single motor unit (SMU) activity do not decrease with an increase in the rate of force generation in standardised vertical or horizontal jaw-force tasks, and (b) there is evidence for functional heterogeneity within the medial pterygoid muscle. METHODS: In 14 healthy participants, electromyographic recordings of the right medial pterygoid muscle were performed with intramuscular fine-wire electrodes during four isometric force tasks: vertical, horizontal contralateral, horizontal protrusion and horizontal ipsilateral, performed at two rates of force development (slow ramp, fast ramp). Computer tomography scans confirmed electrode location within the muscle, which was divided into medial and lateral parts. Force thresholds of onset of discriminated SMUs were compared between rates in each task; significance accepted at p < 0.05. RESULTS: Of 45 SMU force thresholds studied in one or more tasks, there was no significant difference between slow and fast ramp within each force task, except slow ramp thresholds from the lateral part during the vertical force task were significantly higher than fast ramp thresholds. Reversals of recruitment order between tasks provided evidence for functional heterogeneity within the muscle. Force thresholds of the vertical tasks (range: 1-292.6 N) were mostly higher than for the horizontal tasks (range: 0.1-12.5 N). CONCLUSION: The data are consistent with the proposal that the medial pterygoid muscle stabilises the jaw in the vertical plane during isometric force generation in the jaw closing, as well as horizontal directions.

Asunto(s)

RESUMEN

The purpose of this study was to explore the status of the lateral pterygoid muscle (LPM) after detachment in artificial temporomandibular joint replacement (TJR) surgery. Patient clinical and computed tomography imaging data were collected before and after unilateral artificial TJR with LPM detachment. The volume of the LPM on the operated and unoperated sides was measured before and after surgery (at 1, 3, 6, 12 months) using ProPlan CMF 3.0 software. The volumes of the LPM on both sides, the patient's mandibular movements, quality of life (QoL), and pain and diet scores (visual analogue scales) were evaluated and compared at the different follow-up stages. Ten patients were included in the study. After surgery, the volume of the operated LPM was significantly reduced to 60.78% at 3 months (P=0.007), and gradually stabilized to 51.58% at 6 months (P=0.025) and 54.68% at 1 year postoperative (P=0.002). There were no significant LPM volume changes on the unoperated side (P=0.67). Lateral movement of the operated joint was significantly reduced (P=0.021) and correlated with the LPM volume change after surgical detachment (P=0.042). The LPM shrank after detachment in the artificial TJR surgery and the muscle detachment affected the movement of the replaced joint.

Asunto(s)

RESUMEN

A novel total temporomandibular joint replacement (TMJR) was developed with CADskills BV (Ghent, Belgium), aiming to achieve reinsertion of the (LPM) onto a scaffold in the implant. In order to investigate the possibility of reinsertion of the LPM, an animal experiment was conducted. An in vivo sheep experiment was conducted, which involved implanting sheep with a TMJR. Clinical parameters were recorded regularly and computed tomography (CT) scan images of two randomly selected sheep per scan were made at 1, 3, and 6 months. After 9.5 months, the sheep were euthanized, and CT scans of all animals were performed in order to evaluate the LPM's enthesis. A total of 13 sheep were implanted with a TMJR. One sheep was used as a sham. Radiographs revealed four outcome types of enthesis reconstruction. In four sheep, there was no reconstruction between the implant and the LPM. In three sheep, there was a purely soft tissue connection of 0.5-0.9 mm (average 0.7 mm) between the ostectomized bony LPM insertion and the implant's lattice structure. A combination of partial bony and partial soft tissue enthesis attachment (0.3-0.5 mm, average 0.4 mm) was found in three sheep. A bony ingrowth of the enthesis into the scaffold occurred in two sheep. A secondary bony connection between the mandible and the insertion of the LPM was found in 10 of 13 sheep. Four fossa components were found to be displaced, yet TMJ function remained in these ewes. The heterotopic ossification that was seen may be a confounding factor in these results. This in vivo experiment showed promising results for improving the current approach to TMJR with the possibility of restoring the laterotrusive function. The fossa displacement was considered to be due to insufficient fixation and predominant laterotrusive force not allowing for proper osseointegration. Further optimization of the reattachment technique, scaffold position and surface area should be done, as well as trials in humans to evaluate the effect of proper revalidation.

Asunto(s)

RESUMEN

OBJECTIVE: The lateral pterygoid is vital in coordinating multidimensional jaw movements. Since a vector in three-dimensional (3D) space is defined by two 3D points, the role of the lateral pterygoid in 3D jaw movements is defined by its origin and insertion. Reportedly, the lateral pterygoid is inserted into not only the pterygoid fovea but also into the medial surface of the condylar process. The objective was to investigate the morphological features of the region of the lateral pterygoid that inserted into the medial surface of the condylar process. MATERIAL AND METHODS: Ten head halves of seven cadaveric donors were analyzed. In all specimens, the insertion area on the medial surface of the condylar process was measured based on microcomputed tomography images. Muscle fibers were separated into ≥50 small bundles, and positional relationships between the origins and insertions were investigated. RESULTS: Overall, 28.8 ± 5.0% of the insertion area of the lateral pterygoid was situated on the medial surface of the condylar process. Moreover, muscle fiber arrangement revealed that origins of the muscle bundles inserting into the medial surface in seven specimens posteriorly occupied the lateral plate of the pterygoid process longitudinally, whereas those in three specimens mainly occupied the posteroinferior portion. CONCLUSIONS: Muscle bundle inserting on the medial surface of the condylar process had a broad insertion area and a distinct origin on the posterior region of the lateral plate of the pterygoid process. This muscle bundle could act as one of the significant subunits within the lateral pterygoid. Therefore, anatomical coordination mechanisms underlying jaw movement cannot be elucidated without considering this subunit.

Asunto(s)

RESUMEN

OBJECTIVE: Dental occlusion are frequently changed in clinic. Molecular responses in jaw muscles to aberrant dental occlusion are changes are attractive, yet remain are obscure. DESIGN: Unilateral anterior crossbite (UAC) prostheses were applied to Sprague-Dawley rats and then ceased after two weeks to detect the reactions of the masseter, a representative jaw elevator, and the lateral pterygoid muscle (LPM), a representative jaw depressor. RESULTS: Two weeks of UAC elicited mild injury of the two muscles. Myogenesis and protective reactions were detected as increases in αB-crystallin expression in the masseter after 3 days and in the LPM after 2 weeks, and increases in desmin expression in both muscles after 2 weeks. A switch in fibre types from IIb to IIx occurred in the LPM but not in the masseter. Inflammatory responses, shown by the infiltration of inflammatory cells and increases in TNF-α mRNA expression, and fibrosis responses, shown by increased mRNA expression of Type I and III collagens, appeared very mild in the two muscles. These responses were partially recovered by the cessation of UAC. During the whole process, no obvious changes were observed in mitochondrial function, as indicated by the levels of proliferator-activated receptor γ coactivator 1α, mitofusin-2 and voltage-dependent anion channel. CONCLUSIONS: UAC causes injury and very limited inflammatory and fibrosis adaption in the masseter and LPM. Both muscles respond with myogenesis and protective activity. The LPM responds also with muscle fibre isoform alternations. These alterations were partially recovered by the cessation of dental stimulation at an early stage.

Asunto(s)

RESUMEN

OBJECTIVES: To determine (a) whether the medial pterygoid muscle is active in an isometric vertical force task and in isometric horizontal force tasks in the contralateral, protrusion and ipsilateral directions; (b) whether the same single motor units (SMUs) could be active across different directions of isometric force generation; and (c) whether different regions of the medial pterygoid muscle exhibit different patterns of SMU activation during the generation of any one direction of isometric force. METHODS: Intramuscular electromyographic (EMG) recordings were made from the right medial pterygoid muscle in 15 healthy participants during isometric force tasks: vertical and horizontal contralateral, protrusion and ipsilateral. A computed tomography scan divided the EMG recording site into a medial or lateral part in each participant. Single motor units were discriminated in each task. RESULTS: Medial pterygoid SMU activity was recorded in 100% of participants for the vertical biting tasks, 86% of participants for the horizontal contralateral and horizontal protrusion tasks and 57% of the horizontal ipsilateral tasks. Of the 72 SMUs that were discriminated, 36% were active in all tasks; 18% were active only in the vertical tasks and 17% were active in the vertical, horizontal contralateral and horizontal protrusion tasks. The proportion of SMUs that was active in at least 1 horizontal task in the lateral part (33/39) was significantly higher than the proportion (21/33) in the medial part (Chi-Square, P < 0.05). CONCLUSION: The data are consistent with a stabilisation role for the medial pterygoid muscle in isometric jaw forces in the vertical and horizontal planes.

Asunto(s)

RESUMEN

OBJECTIVES: To determine the frequency, morphologic and demographic characteristics, and clinical relevance of the mineralisation of six skull base ligaments (interclinoid, caroticoclinoid, petrosphenoid, posterior petroclinoid, pterygospinous, and pterygoalar). METHODS: This is a retrospective review of 240 CT scans of the paranasal sinuses (ages 6-80 years). A limited systematic review was performed primarily using Embase and Medline databases. RESULTS: Ligamentous mineralisation was well delineated on CT and occurred at ≥ 1 location in 58.3% of patients. There was a nonsignificant trend towards a greater incidence with advancing age. The interclinoid and posterior petroclinoid ligaments were most commonly mineralised (22.1% and 18.3%, respectively); the petrosphenoid and pterygoalar ligaments were least frequently mineralised (10.8% and 6.3%, respectively). The mean age of patients with posterior petroclinoid mineralisation was significantly greater than those with interclinoid and petrosphenoid mineralisation and was not seen in patients aged 6-20 years. The literature review highlighted the clinically relevant potential for mineralised ligaments to cause barriers to surgical access (e.g. to the foramen ovale), increase the risk of neurovascular injury during surgery at the skull base (e.g. during anterior clinoidectomy), and predispose to neural impingement. CONCLUSIONS: Skull base ligamentous mineralisation is commonly encountered on CT imaging. Given the potentially significant clinical implications, an understanding of the morphological appearances is of importance to those planning interventions at the skull base. To the authors' knowledge, this study is the first to comprehensively evaluate such a wide range of skull base ligaments using CT. For some ligaments, the incidence on CT has not been previously described.

RESUMEN

The sphenoidal tubercle is a bone elevation located in the anterior edge of the infratemporal crest of the sphenoid greater wing, where the temporal and lateral pterygoid muscles have their origin. This bone accident presents varied morphology so its description and denomination are a topic of discussion. 60 dry skulls obtained from the morphology laboratory of the Biomedical Basic Sciences Department of the University of Talca were used for a morphological and morphometric analysis of the sphenoidal tubercle including its morphology, diameters (anteroposterior, transverse and vertical) and the distance to the grooves for the maxillary artery and maxillary nerve. Sphenoidal tubercle had a prevalence of 98.4 % of all dry skulls analyzed with a bilateral presentation in the 76.6 % of the cases. According to its different forms of presentation established by Cáceres et al., (2016) the pyramidal form was the most frequent with a 25.7 %. The average diameters were of 4.12 mm anteroposterior, 5.50 mm transverse and 3.89 mm vertical. The average distance to the grooves of the maxillary artery and maxillary nerve were 9.04 mm and 7.6 mm, respectively. Sphenoidal tubercle is a constant bone accident with a variated morphology and measures. Due to its anatomical relations with important neurovascular elements such as the maxillary artery and the maxillary nerve, it may be used as a reference point for surgical access to the infratemporal fossa. From this analysis we establish that the denomination of "infratemporal process" is more accurate, because the development of this bone accident is from muscular traction performed by the lateral pterygoid muscle and the deep portion of the temporal muscle causing great variations in its morphology, probably due to external and functional parameters or even influenced by the biotype.

El tubérculo esfenoidal es una elevación ósea ubicada en el extremo anterior de la cresta infratemporal del ala mayor del hueso esfenoides, donde presta inserción al músculo temporal y pterigoideo lateral. Presenta morfología variada, por lo que su descripción y denominación resultan motivo de discusión. 60 cráneos secos obtenidos del Laboratorio de Morfología del Departamento de Ciencias Básicas Biomédicas de la Universidad de Talca, fueron utilizados para realizar un análisis morfológico y morfométrico del tubérculo esfenoidal evaluando forma, diámetros (anteroposterior, laterolateral y vertical) y distancia con el surco de la arteria y nervio maxilar. El tubérculo esfenoidal tuvo una prevalencia del 98,4 % del total de cráneos analizados, presentándose bilateralmente en el 76,6 % de los casos. De acuerdo a las diferentes formas de presentación establecidas por Cáceres et al (2016) la forma piramidal fue la más frecuente con un 25,7 %. Los diámetros promedio fueron de 4,12 mm anteroposterior, 5,50 mm laterolateral y 3,89 mm vertical. Las distancias promedio con el surco de la arteria y nervio maxilar fueron de 9,04 mm y 7,6mm, respectivamente. El tubérculo esfenoidal es un accidente óseo constante de morfología y dimensiones variadas. Debido a sus relaciones con elementos vasculares de importancia, tales como la arteria y nervio maxilar, podría ser utilizado como elemento de referencia para el acceso quirúrgico a la fosa infratemporal. A partir de su análisis planteamos que su denominación como "proceso infratemporal" sería más apropiado, debido a que se desarrollaría a partir de la tracción muscular ejercida por el musculo pterigoideo lateral y la porción profunda del músculo temporal, ocasionando variaciones notables en su morfología, probablemente debido a factores externos y funcionales o incluso influenciada por el biotipo.

Asunto(s)

RESUMEN

Temporomandibular joint disorders (TMDs) usually present with symptoms and signs such as pain, mandibular movement, dysfunction, or joint sounds. Botulinum toxin type A (BTX-A) is a biologic toxin which inhibits skeletal muscle through hindering the production of acetylcholine in the nerve endings. This toxin is used for the treatment of hyperactivity of lateral pterygoid muscle and TMD symptoms. This comprehensive review aimed to evaluate the effect of BTX-A injections in the lateral pterygoid muscle on treatment of TMDs symptoms. In this study, online databases including Scopus, Medline, Ebsco, Cochrane, EMBASE, and Google scholar were searched for the keywords "pterygoid muscle" and "Onabotulinumtoxin A". Twenty-four articles were eligible to be enrolled in the study. In 4 interventional studies and 20 descriptive studies, BTX-A was used for the treatment of TMDs. The dosage and number of injections were different in each study; however, the injection methods were relatively similar. Regardless of the type, number of injections, and dosage, injection of BTX-A in lateral pterygoid seems effective in reducing the click sound and other TMJ-related muscle disorders such as pain, hyperactivity, and dysfunction.

RESUMEN

There is limited information of the normal function of the human medial pterygoid muscle (MPt). The aims were to determine whether (i) the MPt is active throughout horizontal jaw movements with the teeth apart and (ii) whether single motor units (SMUs) are active during horizontal and opening-closing jaw movements. Intramuscular electrodes were placed in the right MPt of 18 participants who performed five teeth-apart tasks: (i) postural position, (ii) ipsilateral (i.e. right) jaw movement, (iii) contralateral movement, (iv) protrusive movement and (v) opening-closing movement. Movement tasks were guided by a target and were divided into BEFORE, OUT, HOLDING, RETURN and AFTER phases according to the movement trajectories recorded by a jaw tracking system. Increased EMG activity was consistently found in the OUT, HOLDING and RETURN phases of the contralateral and protrusive movement tasks. An increased RETURN phase activity in the ipsilateral task indicates an important role for the MPt in the contralateral force vector. Of the 14 SMUs active in the opening-closing task, 64% were also active in at least one horizontal task. There were tonically active SMUs at the postural jaw position in 44% of participants. These new data point to an important role for the MPt in the fine control of low forces as required for stabilisation of vertical mandibular position not only to maintain postural position, but also throughout horizontal jaw movements with the teeth apart. These findings provide baseline information for future investigations of the possible role of this muscle in oro-facial pain conditions.

Asunto(s)

RESUMEN

Published descriptions about the sites of origin of the human medial pterygoid muscle vary and there are few reports on the distribution and density of muscle spindles in this muscle. We aimed to: (1) determine the extent of anatomical variability in the origins and insertions of the superficial and deep heads of the human medial pterygoid muscle and (2) determine the extent of variation in the distribution of spindles in the two heads of the muscle. Thirty-nine human cadaver hemi-heads were dissected and the attachments of the medial pterygoid muscle examined. The whole muscle was removed, weighed, cut into segments and embedded in wax for light microscopy. Sections were stained with Weigert-Van Gieson stain and scanned into digital images. Spindles were manually counted. In seven specimens, the deep head of the muscle arose from the medial surface of the lateral pterygoid plate and the pterygoid fossa. In 28 specimens, the origin extended onto the lateral surface of the medial pterygoid plate. There were abundant muscle spindles in the middle of the muscle, slightly fewer 1 cm toward the insertion, significantly fewer 1 cm toward the origin, and few or no spindles near the origins of the superficial and deep heads or near their insertion. In conclusion, firstly, this study shows that in 72% of the specimens examined, the origin of the medial pterygoid is wider than conventionally described in anatomical textbooks. Secondly, the segmental distribution of muscle spindles is described for the first time. Clin. Anat. 30:1064-1071, 2017. © 2017 Wiley Periodicals, Inc.

Asunto(s)

RESUMEN

BACKGROUND: Fractures of mid-face were first described by Le Fort and are classified into three categories - Le Fort I, Le Fort II and Le Fort III. The pterygoid processes of the sphenoid bone are fractured in all the three categories of Le Fort fractures as the sphenoid bone connects the cranium vault to the facial bones. Fractures of the pterygoid processes without associated Le Fort fractures are rare and are usually associated with fractures of the mandible, temporal bone or other facial bones. An isolated fracture of pterygoid plates without associated Le Fort fractures or fractures of other mid-face bones are exceedingly rare. CASE REPORT: We present a case of an isolated fracture of the right lateral pterygoid plate by a penetrating foreign body (wooden twig) in an adult male who presented with discharging sinus in the oropharynx. The presence of the foreign body was confirmed on computed tomography and was removed under general anesthesia via submandibular incision. The patient had an uneventful postoperative hospital stay and was asymptomatic on a follow-up five months later. CONCLUSIONS: This article emphasizes the fact that pterygoid plates may be fractured without an associated Le Fort fracture or a fracture of the mandible. This is the first case of an isolated pterygoid plate fracture in the literature.

RESUMEN

BACKGROUND: The maxillary artery (MA) has gained attention in neurosurgery particularly in cerebral revascularization techniques, intracranial endonasal approaches and endovascular procedures. OBJECTIVES: To describe and illustrate the anatomy of the MA and its neurosurgical importance in a detailed manner. METHODS: Six cadaveric heads (12 MAs) were injected with latex. The arteries and surrounding structures were dissected and studied using microsurgical techniques. The dimensions, course and branching patterns of the MA were recollected. In addition, 20 three-dimensional reconstruction CT head and neck angiograms (3D CTAs) of actual patients were correlated with the cadaveric findings. RESULTS: The MA can be divided in three segments: mandibular, pterygoid and pterygopalatine. Medial and lateral trunk variants regarding its course around the lateral pterygoid muscle can be found. The different branching patterns of the MA have a direct correlation with the course of its main trunk at the base of the skull. Branching and trunk variants on one side do not predict the findings on the contralateral side. CONCLUSION: In this study the highly variable course, branching patterns and relations of the MA are illustrated and described in human cadaveric heads and 3D CTAs. MA 3D CTA with bone reconstruction can be useful preoperatively for the identification of the medial or lateral course variants of this artery, particularly its pterygoid segment, which should be taken into account when considering the MA as a donor vessel for an EC-IC bypass.

Asunto(s)

RESUMEN

OBJECTIVES: The aim of this study was to investigate the correlation between the lateral pterygoid muscle (LPM) attachment type and temporomandibular joint (TMJ) disc position on sagittal and coronal MR scans. METHODS: 191 patients (148 females, 43 males), aged 14-60 years, underwent MR investigations of the TMJs in the intercuspal position (IP) and open-mouth position (OMP). The disc position was evaluated on oblique sagittal and coronal images in the IP and OMP on many MRI sections showing all portions of the joint. Relationships between the LPM attachment patterns and articular disc positions were evaluated by z and χ2 tests. RESULTS: Three types of the LPM attachment were found. There was a statistically significant correlation between the LPM attachment type and the disc position in IP (χ2 = 24.29; p < 0.01). The type of muscle attachment did not determine the prevalence of normal, lateral and medial disc positions. There were differences between the muscle attachment types in the anterior, anteromedial and anterolateral disc positions. There was a statistically significant association between TMJ disc position in OMP and particular attachment types in the sagittal plane (χ2 = 9.702; p < 0.01). CONCLUSIONS: Certain types of the LPM insertion are correlated with TMJ disc position.

Asunto(s)

RESUMEN

PURPOSE: Lateral pterygoid muscle (LPM) plays an important role in jaw movement and has been implicated in Temporomandibular disorders (TMDs). Migraine has been described as a common symptom in patients with TMDs and may be related to muscle hyperactivity. This study aimed to compare LPM volume in individuals with and without migraine, using segmentation of the LPM in magnetic resonance (MR) imaging of the TMJ. MATERIALS AND METHODS: Twenty patients with migraine and 20 volunteers without migraine underwent a clinical examination of the TMJ, according to the Research Diagnostic Criteria for TMDs. MR imaging was performed and the LPM was segmented using the ITK-SNAP 1.4.1 software, which calculates the volume of each segmented structure in voxels per cubic millimeter. The chi-squared test and the Fisher's exact test were used to relate the TMD variables obtained from the MR images and clinical examinations to the presence of migraine. Logistic binary regression was used to determine the importance of each factor for predicting the presence of a migraine headache. RESULTS: Patients with TMDs and migraine tended to have hypertrophy of the LPM (58.7%). In addition, abnormal mandibular movements (61.2%) and disc displacement (70.0%) were found to be the most common signs in patients with TMDs and migraine. CONCLUSION: In patients with TMDs and simultaneous migraine, the LPM tends to be hypertrophic. LPM segmentation on MR imaging may be an alternative method to study this muscle in such patients because the hypertrophic LPM is not always palpable.

RESUMEN

OBJECTIVE: The aim of this anatomical study was to determine if a needle is able to reach the lateral pterygoid muscle during the application of dry needling technique. METHODS: A dry needling approach using 2 needles of 50 to 60 mm in length, one inserted over the zygomatic process posterior at the obituary arch (for the superior head) and other inserted below the zygomatic process between the mandibular condyle and the coronoid process (for the inferior head), was proposed. A progressive dissection into 3 stages was conducted into 2 heads of fresh male cadavers. First, dry needling of the lateral pterygoid muscle was applied on the cadaver. Second, a block dissection containing the lateral pterygoid was harvested. Finally, the ramus of the mandible was sectioned by osteotomy to visualize the lateral pterygoid muscle with the needle placements. RESULTS: With the needles inserted into the cadaver, the block dissection revealed that the superior needle reached the superior (sphenoid) head of the lateral pterygoid muscle and the inferior needle reached the inferior (pterygoid) head of the muscle. At the final stage of the dissection, when the ramus of the mandible was sectioned by osteotomy, it was revealed that the superior needle entered into the belly of the superior head of the lateral pterygoid muscle. CONCLUSIONS: This anatomical study supports that dry needling technique for the lateral pterygoid muscle can be properly conducted with the proposed approach.

Asunto(s)