Curious Case of Facial Pain Mimicking Temporomandibular Disorder.

Facial pain is a common but complex complaint, frequently associated with dental issues or temporomandibular disorder (TMD). However, rare aetiologies can complicate conventional diagnoses and treatment approaches. We present a case of a 36-year-old male with persistent jaw pain and restricted mandibular movement, initially managed as a typical TMD case. Conventional treatments yielded no improvement, prompting advanced imaging, which identified an unusual mass within the lateral pterygoid muscle. A surgical excision of the mass was performed, and histopathological examination revealed a rare and unexpected diagnosis. This case highlights the importance of considering uncommon conditions in the differential diagnosis of TMD and facial pain to ensure timely and appropriate therapeutic interventions.

Correlation between GLCM-based texture features of the lateral pterygoid muscle and cognitive function in patients with idiopathic normal pressure hydrocephalus: a preliminary report.

PURPOSE: The potential relationship between mastication ability and cognitive function in idiopathic normal pressure hydrocephalus (iNPH) patients is unclear. This report investigated the association between mastication and cognitive function in iNPH patients using the gray level of the co-occurrence matrix on the lateral pterygoid muscle. METHODS: We analyzed data from 96 unoperated iNPH patients who underwent magnetic resonance imaging (MRI) between December 2016 and February 2023. Radiomic features were extracted from T2 MRI scans of the lateral pterygoid muscle, and muscle texture parameters were correlated with the iNPH grading scale. Subgroup analysis compared the texture parameters of patients with normal cognitive function with those of patients with cognitive impairment. RESULTS: The mini-mental state examination score correlated positively with the angular second moment (P < 0.05) and negatively with entropy (P < 0.05). The dementia scale (Eide's classification) correlated negatively with gray values (P < 0.05). Gray values were higher in the cognitive impairment group (64.7 ± 16.6) when compared with the non-cognitive impairment group (57.4 ± 13.3) (P = 0.005). Entropy was higher in the cognitive impairment group (8.2 ± 0.3) than in the non-cognitive impairment group (8.0 ± 0.3) (P < 0.001). The area under the receiver operating characteristic curve was 0.681 (P = 0.003) and 0.701 (P < 0.001) for gray value and entropy, respectively. CONCLUSION: Our findings suggest an association between heterogeneity of mastication and impaired cognitive function in iNPH patients and highlight muscle texture analysis as a potential tool for predicting cognitive impairment in these patients.

A new and simplified extraoral approach for inferior alveolar nerve block: a cadaveric study and clinical case reports.

PURPOSE: Inferior alveolar nerve (IAN) and lingual nerve (LN) blocks are commonly performed using the intraoral landmark techniques. However, these methods have a risk of unanticipated nerve and arterial injury or a higher failure rate. We developed a novel extraoral approach for the IAN and LN blocks, the "inferior alveolar nerve block mandibular angle approach (IANB-MA)," using ultrasound guidance. The mechanism of action of this nerve block was examined anatomically, and its clinical feasibility was reported. METHODS: We performed the IANB-MA on four cadavers using different dye volumes (2, 4, 6 and 8 mL). The ultrasound probe was placed on the lower edge of the mandibula of each cadaver, and the needle was advanced to the mandibular inner surface. Blue acrylic paint solution was injected, and its spread was evaluated by dissection. RESULTS: Our study showed that the medial pterygoid muscle fascia was stained in all cadavers. The dye reached the LN consistently, and the IAN was stained with higher volumes (6 mL and 8 mL). The pterygomandibular space was filled with 6 mL and 8 mL of the dye. The IANB-MA successfully reduced pain in three patients with trigeminal neuralgia, tongue or jaw pain. CONCLUSIONS: The IANB-MA is a novel ultrasound-guided approach to the IAN and the LN. The clinical feasibility and effectiveness of this technique were confirmed in our patients. It may be a good alternative analgesic approach to other conventional approaches.

Dysphagia and Trismus After Tooth Extraction : Clinical Conondrum.

Clinicians should consider disorders of masticatory muscle including lateral pterygoid muscle as a differential diagnosis in patients presenting with dysphagia and trismus after tooth extraction.

New T staging recommendations for recurrent nasopharyngeal carcinoma.

OBJECTIVE: The International Union for Cancer Control/American Joint Committee on Cancer (UICC/AJCC) rT staging is not clinically practical for recurrent nasopharyngeal carcinoma (rNPC). The aim of this study was to establish a new rT staging to guide the treatment of rNPC. METHODS: We conducted a retrospective analysis of 175 patients diagnosed with rNPC between January 2012 and December 2020, using ROC curve analysis to evaluate its effectiveness. RESULTS: We analyzed the overall survival (OS) and progression-free survival(PFS) of patients diagnosed with rNPC according to the 8th (UICC/AJCC) rT staging, and found that the overall survival of rT1 and rT2 patients (OS; 29.98% vs. 27.09%, p = 0.8059) and progression-free survival (PFS; 28.48% vs. 26.12%, p = 0.4045) had no significant difference. In rT1 and rT2 patients of this study, overall survival(OS; 30.44% vs. 24.91%, p = 0.0229) and progression-free survival(PFS 29.12% vs. 24.03%, p = 0.0459) had a significant difference. Smoking, family history, and time interval of initial recurrence were independent prognostic factors for OS and PFS. CONCLUSION: The new rT staging of this study has a better predictive value for survival of rNPC patients than the 8th (UICC/AJCC) rT staging.

Anatomical factors influencing temporomandibular joint clicking in young adults: temporomandibular joint structure disorder or lateral pterygoid muscle dysfunction?

Objective: This study aimed to investigate the selected anatomical factors that can potentially influence temporomandibular joint (TMJ) clicking in young adults by assessing TMJ structures and lateral pterygoid muscle (LPM) function using magnetic resonance imaging (MRI). Methods: The patients were divided into four groups: the healthy control group; the clicking on mouth opening group; the clicking on mouth closing group; and the clicking on mouth opening and closing group. Additionally, we used clinical palpation to evaluate the masticatory muscles' functional state and employed MRI using the OCOR-T1WI-FSE-CLOSED, OSAG-PDW-FSE-CLOSED, and OSAG-PDW-FSE-OPEN sequences to analyze the texture of the lateral pterygoid muscle (LPM). Results: The proportion of any articular disc or condylar morphology class did not differ significantly between the TMJ clicking and HC groups. The articular disc position did not differ significantly between the TMJ clicking and HC groups. In the TMJ clicking group, the presence of masticatory muscle dysfunction differed significantly between the clicking and non-clicking sides. Moreover, the LPM accounted for the highest proportion among masticatory muscles with tenderness in all TMJ clicking subgroups (77.78%-100%). Therefore, in the TMJ clicking group, the LPM texture was less defined, more uniform in gray scale, and more similar to local texture (p < 0.0001). Conclusion: The occurrence of TMJ clicking in young adults is unrelated to the TMJ structure but related to the function of masticatory muscles, particularly the LPM.

Anatomical study to determine a new approach to treat benign masses located in the anterior condyle region: a case report.

A 22-year-old male patient presented to the clinic with severe pain in the preauricular area with an inability to completely occlude the jaw. Facial computed tomography and magnetic resonance imaging revealed a well-defined lesion that was tentatively diagnosed as a benign tumor or cystic mass. Surgical approach of a lesion in the condyle is delicate and problematic as many vulnerable anatomical structures are present. There are several methods for surgery in this area. Typically, an extraoral approach is dangerous because of potential injuries to nerves and arteries. The intraoral approach also presents difficulties due to the lack of visibility and accessibility. On occasion, coronoidectomy may be performed. The goal here was to determine an easier and safer new surgical approach to the condyle. We reached the anterior part of the pterygoid plate in the same method as in Le Fort I surgery. From this point, through the external pterygoid muscle, approaching the anterior aspect of the condyle is relatively easy and safe, with minimal damage to the surrounding tissues. Pus was drained at the site, and the lesion was diagnosed as an abscess. Pain and inability to close the mouth resolved without recurrence.

Lateral Pterygoid Muscle Alteration in Patients Treated Surgically Due to Mandibular Head Fractures.

The goal of surgical treatment of mandibular head fracture is to restore anatomical relations; however, it also carries other implications. The purpose of this study is to present the alteration in the size of lateral pterygoid muscles after surgical treatment of unilateral mandibular head fractures and the impact of this change on the range of motion of the mandible. Another issue addressed is the persistence of changes in the appearance of the lateral pterygoid muscles after surgical treatment. In this study, 66 patients with unilateral mandibular head fracture were included. An additional 15 patients from this group who were treated only conservatively were separated as an extra reference group to exclude completely the effect of surgery on the appearance of the pterygoid lateral muscle (even on the opposite side to the surgically treated side). The range of mandibular movements was measured at specific time intervals up to 24 months post-operationally. Then, the lengths and widths of the lateral pterygoid muscles on the operated and healthy site were measured in CT images. The results were compared with a control group which consisted of muscles of the intact site (opposite site to the fracture). A significant reduction in the length-to-width ratio of the lateral pterygoid muscle on the operated side by approx. 20% is observed. This suggests that the muscle becomes more spherical, and thus the range of lateral movement to the contralateral side is permanently reduced.

Training of the lateral pterygoid muscle in the treatment of temporomandibular joint disc displacement with reduction: A randomised clinical trial.

BACKGROUND: Disc displacement with reduction (DDwR) therapy should be performed only when pain or discomfort is presented. Data on treatment options for painful DDwR are very limited. OBJECTIVE: The aim was to investigate whether isometric training of the lateral pterygoid muscle (LPM) is equivalent to stabilisation appliance therapy with regard to the treatment of painful DDwR. The training program is based on the science of Janda. METHODS: This was a prospective, randomised study with a comparative treatment group. Sixty patients (≥18 years) with DDwR and pain were randomly assigned to two groups: (1) muscle training and (2) stabilisation appliance. The following variables were recorded at baseline examination and after 2, 4 and 6 months: changes in orofacial pain, clicking sounds of the temporomandibular joint (TMJ), force degrees for the lateral movement of the mandible and interincisal opening distance. p values of <.05 were considered statistically significant but 95% confidence intervals were also presented. RESULTS: A decrease in orofacial pain intensity was seen in both groups (p < .0001). Registered TMJ clicking disappeared after 6 months of treatment in 37% (n = 11) of the patients in the training group and in 27% (n = 8) of the appliance group (p = .0009 and p = .0047). Muscle training showed 27 improvements in Janda force degrees at the end of the study (p < .0001). CONCLUSION: Muscle training and appliance therapy improved mouth opening and reduced pain intensity in both patient groups. Muscle training might be a promising option in the treatment of patients suffering from painful DDwR.

Magnetic resonance image texture analysis of the lateral pterygoid muscle in patients with rheumatoid arthritis: a preliminary report.

OBJECTIVES: Magnetic resonance imaging (MRI) is useful for assessing temporomandibular disorders (TMDs). However, few studies have attempted texture analysis of the lateral pterygoid muscle in patients with rheumatoid arthritis (RA). This study aims to investigate the usefulness of MRI texture analysis of the lateral pterygoid muscle of patients with RA of the temporomandibular joint (TMJ). METHODS: We analyzed the data from 36 patients (18 non-RA patients and 18 RA patients) who complained of pain and underwent MRI between April 2008 and August 2021. From the MRI scans of these patients, 279 radiomics features were extracted using STIR image data of the ROIs on the lateral pterygoid muscle of patients with RA and analyzed using MaZda ver. 3.3. Seven gray-level co-occurrence matrix features (Sum entropy, Sum variance) were picked up using the Fisher coefficient, for comparison between the RA and non-RA groups. Data analysis was performed using the Mann-Whitney U test A P value of < 0.05 was considered as statistically significant. RESULTS: All seven lateral pterygoid muscle radiomic features indicated significant differences between the non-RA and RA groups (P < 0.05). CONCLUSION: MRI texture analysis shows potential for application in radiomics diagnosis of RA in TMJ.

Ultrasound-guided lateral pterygoid muscle botulinum toxin: an injection for recurrent temporomandibular joint dislocation in a brain injury patient.

Botulinum toxin type A (BTX-A) injection using nerve stimulation or electromyography for recurrent temporomandibular joint (TMJ) dislocation has been reported for several years. However, using the available equipment like a nerve stimulator or an electromyograph is uncommon, and ultrasound guidance is convenient and requires no additional resources. In this report, we used ultrasound as a tool to achieve BTX-A injections in a patient with a traumatic brain injury to treat her TMJ dislocation. One week after the injections, she had no more dislocation. She remained symptom free during the 3 months of follow-up, and her clinical symptoms improved without significant complications. This is the first report using ultrasound guidance for BTX-A injections to treat recurrent TMJ dislocation. This treatment is an effective and safe technique that could be performed timely and locally without referral to a center with electromyography facilities.

Gender differences in lateral pterygoid muscle in patients with anterior disk displacement.

OBJECTIVE: To use quantitative MRI to assess gender differences in lateral pterygoid muscle (LPM) characteristics in patients with anterior disk displacement (ADD). METHODS: Lateral pterygoid muscle of 51 patients diagnosed with temporomandibular joint disorders (TMD) who underwent T1-weighted Dixon and T1-mapping sequences were retrospectively analyzed. There were 34 female patients (10 with bilateral normal position disk [NP]; 24 with bilateral ADD) and 17 male patients (eight with bilateral NP; nine with bilateral ADD) among them. After controlling for age, differences in fat fraction, T1 value, volume and histogram features related to gender and disk status were tested with 2-way ANCOVA or Quade ANCOVA with Bonferroni correction. RESULTS: Volume of LPM in NP was significantly smaller than that of ADD (p < 0.001). Fat fraction of LPM in females with NP was significantly higher than males with NP (p < 0.05). Females with ADD showed a significantly higher T1 value (p < 0.05), and higher intramuscular heterogeneity than males with ADD. CONCLUSIONS: Lateral pterygoid muscle in female TMD patients presented more fatty infiltration in the NP stage and might present more fibrosis in the ADD stage compared with males. Together, this leads to more serious intramuscular heterogeneity during the pathogenesis of ADD in females.

Rare Intramuscular Myxoma Involving the Pterygoid and Masseteric Muscles: A Case Report.

Myxomas, characterized by abundant mucoid stroma and spindle cells, represent a subset of benign soft tissue tumors. Intramuscular myxomas in the maxillofacial region are rare, posing diagnostic challenges. We present the case of a 58-year-old male who reported limited jaw movement. Physical examination revealed asymmetry, restricted mouth opening, and left lateral jaw movement. Imaging confirmed a well-defined myxomatous mass. Core needle biopsy confirmed an intramuscular myxoma involving the pterygoid and masseteric muscles. A multidisciplinary team opted for surveillance due to its benign nature. Follow-up at six months showed stable findings, supporting the decision for non-surgical management. This case highlights the diagnostic and management challenges of rare intramuscular myxomas in the maxillofacial region. A comprehensive diagnostic work-up, including clinical, radiological, and histopathological data, is crucial. Non-surgical management, guided by a benign nature, underscores the importance of judicious and multidisciplinary approaches. Regular follow-up contributes to understanding the natural history of intramuscular myxomas, emphasizing the need for vigilant monitoring in soft tissue tumor management.

Efecto de la dibucaína sobre la SERCA del músculo pterigoideo interno / Drug action of dibucaine on the SERCA from medial pterygoid muscle

Objetivo: Determinar el efecto del anestésico local di-bucaína sobre las principales isoformas de la SERCA (calcio ATPasa de retículo sarco-endoplásmico) pre-sentes en músculo pterigoideo interno. Métodos: Se aislaron por centrifugación diferencial membranas de retículo sarcoplásmico de pterigoideo interno de conejo neozelandés macho (n=5). Se separaron las isoformas SERCA1a, 2a y 2b por cromatografía de afinidad. Se determinó in vitro la actividad enzimá-tica en presencia de diferentes concentraciones de dibucaína (0-90 mM) por el método de Fiske y Subba-row, realizando 5 experimentos por duplicado y en paralelo para cada isoforma. Se calculó la media y ES de la CI50 (mM) del anestésico para cada isofor-ma y éstas se compararon por ANOVA de una vía (p<0,05), y prueba Student-Newman-Keuls de com-paraciones múltiples. Resultados: Dibucaína inhibió la actividad enzimática en función de su concentra-ción en las tres isoformas en estudio. Las CI50 fueron: SERCA1a 20,02 ± 0,64 mM, SERCA2a 15,03 ± 0,52 mM y SERCA2b 16,00 ± 0,51 mM y resultaron signi-ficativamente diferentes (F2,27 = 11,08, p<0,001). La prueba post hoc identificó diferencias significativas entre SERCA1a y 2a, 1a y 2b. El efecto inhibitorio re-sultó significativamente mayor sobre las isoformas 2a y 2b, cuya presencia es sustancialmente mayor en músculos masticadores. Conclusión: La dibucaína inhibe a la SERCA de pterigoideo interno a concen-traciones menores que las usadas en clínica médica (29 mM). Es un anestésico local con potencial efecto miotóxico derivado de la inhibición de la SERCA (AU)

Aim: To test the effect of the local anesthetic dibu-caine on the main isoforms of the SERCA (sarco-endosplasmic reticulum calcium-ATPase) in medial pterygoid muscle. Methods: Sarcoplasmic reticulum membranes from male New Zealand rabbits (n=5) were isolated from medial pterygoid muscle by ul-tracentrifugation. The isoforms SERCA1a, 2a and 2b were separated using high affinity chromatography. In vitro enzymatic activity determinations were per-formed in the presence of different dibucaine con-centrations (0-90 mM) using the colorimetric method described by Fiske & Subbarow. Five assays in dupli-cate and run in parallel were performed for each of the isoforms. Mean and SEM of the IC50 (mM) for the effect of the anesthetic on each isoform were calcu-lated and compared by one-way ANOVA (p<0.05), and Student-Newman-Keuls multiple comparisons test. Results: Dibucaine inhibited the enzymatic activity in a concentration-dependent manner for the three studied isoforms. The IC50 values were: SERCA1a 20.02 ± 0.64 mM, SERCA2a 15.03 ± 0.52 mM and SER-CA2b 16.00 ± 0.51 mM. The values were significantly different (F2.27 = 11.08, p<0.001). The post hoc test revealed significant differences between SERCA1a and 2a, 1a and 2b. The inhibitory effect was signifi-cantly higher on 2a and 2b isoforms, whose presence is substantially higher in masticatory muscles. Con-clusion: Dibucaine inhibits SERCA in medial pterygoid muscle at concentrations lower than those used in clinical medicine (29 mM). It is a potentially myotoxic local anesthetic whose toxic effect may derive from SERCA inhibition (AU)

Promising minimally invasive treatment modalities for symptomatic temporomandibular joint disc displacement with reduction: a randomized controlled clinical trial.

BACKGROUND: Pain and clicking are the primary complaints in patients suffering from temporomandibular joint disc displacement with reduction (DDwR), negatively affecting the patients' quality of life, making the treatment essential. This prospective randomized controlled trial (RCT) was conducted to evaluate the effectiveness of botulinum toxin type-A (BTX-A) and low level laser therapy (LLLT) in comparison to anterior repositioning appliance (ARA) for the treatment of DDwR. METHODS: A total of 27 patients were randomly allocated to 3 groups; ARA (control group), BTX-A, and LLLT; with 9 patients each. All patients were evaluated before and 3 months after the treatment using a visual analogue scale (VAS) and magnetic resonance imaging (MRI). RESULTS: At 3 months follow-up, all groups showed a significant reduction in pain assessed by VAS (P = 0.007). Measured on MRI, there was a significant improvement in disc position and joint space index (JSI) in BTX-A group (P < 0.001, P = 0.011) and LLLT group (P = 0.002, P = 0.017) in comparison to the control group (P = 0.087, P = 0.066) respectively. As for time of recovery, a statistically significant difference was observed in BTX-A group (P < 0.001) and LLLT (P < 0.001) group in comparison to ARA group, which showed the most prolonged duration for reduction of DDwR symptoms. CONCLUSION: We concluded that BTX-A and LLLT could be considered effective alternative treatment modalities to ARA regarding reducing joint pain, clicking, and improving disc position in patients with symptomatic DDwR. TRIAL REGISTRATION: This prospective double-blinded RCT has been registered at ClinicalTrials.gov with identification number: NCT05194488, 18/1/2022.

Macroscopic analysis of the insertion points of the lateral pterygoid muscle in adult individuals / Análisis macroscópico de los lugares de inserción del músculo pterigoideo lateral en individuos adultos

SUMMARY: The lateral pterygoid muscle (LPM) is intimately related with the temporomandibular joint (TMJ), playing an important role in its physiology. This makes it of interest to researchers who investigate temporomandibular disorders. The literature indicates that anatomical variations exist in the insertion of the superior fascicle of the LPM. Imaging and cadaver studies have revealed that the LPM may present an accessory fascicle. The study object was to carry out macroscopic analysis of the LPM, examining the origin and insertion of its superior and inferior fascicles. The study used 38 half-heads of adult individuals fixed in formaldehyde 10 %. To carry out macroscopic analysis of the LPM, an initial incision was made along the lower margin of the zygomatic arch; the origin of the masseter muscle was then dissected, separating its insertion on the lateral face of the mandibular ramus and retracting the muscle to posteroinferior. Two incisions were made on the zygomatic arch and the insertion of the temporal muscle on the coronoid process was identified with dissection pincers; it was dissected to gain access to the infratemporal fossa and the two fascicles of the LPM. The superior fascicle (SF) originated on the infratemporal face of the greater wing of the sphenoid, and on the superior third of the lateral face of the lateral lamina of the pterygoid process of the sphenoid in 26 samples. In 12 samples, it originated on the greater wing of the sphenoid and the infratemporal crest of the sphenoid. Type I insertion was found in 20 samples, Type II in 6 samples and Type III in 12 samples. In all the samples analysed, the inferior fascicle (IF) originated on the inferior two thirds of the lateral face of the lateral lamina of the pterygoid process and on the lateral face of the pyramidal process of the palatine, with insertion on the pterygoid fovea. The accessory fascicle (AF) of the LPM was present in 6 samples. The AF originated on the greater wing of the sphenoid in 2 cases and inferior to the superior fascicle in 4 cases; its insertion was on the capsular disc complex in all cases. The results obtained in our study contribute anatomical data on the LPM in Brazilian adult individuals, with evaluation of its insertion points.

El músculo pterigoideo lateral (MPL) presenta íntima relación con la articulación temporomandibular (ATM) y desempeña un rol importante en la fisiología de esta articulación, despertando el interés de investigadores que se dedican al estudio de los trastornos temporomandibulares. La literatura señala que existen variaciones anatómicas del MPL, con respecto a la inserción del fascículo superior. Los estudios cadavéricos e imagenológicos han revelado que el MPL puede presentar un fascículo accesorio. El objetivo del estudio fue realizar un análisis macroscópico del MPL, examinando el origen e inserción de sus fascículos superior e inferior. Se utilizaron 38 hemicabezas de individuos adultos fijadas en formaldehído al 10 %. Para realizar el análisis macroscópico del MPL se realizó inicialmente una incisión a lo largo del margen inferior del arco cigomático, luego se seccionó el origen del músculo masétero separando su inserción en la cara lateral de la rama de la mandíbula, retrayendo al músculo en sentido posteroinferior. Se hicieron dos cortes en el arco cigomático y con pinzas de disección se identificó la inserción del músculo temporal en el proceso coronoides, el cual se seccionó para ingresar a la fosa infratemporal y acceder a ambos fascículos del MPL. El fascículo superior (FS) del MPL se originó en la cara infratemporal del ala mayor del esfenoides y en el tercio superior de la cara lateral de la lámina lateral del proceso pterigoides del esfenoides en 26 muestras. En 12 muestras se originó en el ala mayor del esfenoides y cresta infratemporal del esfenoides. Con relación a su inserción, se encontró el Tipo I en 20 muestras; el Tipo II en 6 muestras y el Tipo III en 12 muestras. En todas las muestras analizadas el origen del fascículo inferior (FI) del MPL fue en los dos tercios inferiores de la cara lateral de la lámina lateral del proceso pterigoides y en la cara lateral del proceso piramidal del palatino insertándose en la fóvea pterigoidea. El fascículo accesorio (FA) del MPL estuvo presente en 6 muestras. El FA se originó en el ala mayor del esfenoides en 2 casos e inferior al fascículo superior en 4 casos y su inserción, en el complejo disco capsular en todos los casos. Mediante los resultados obtenidos en nuestro estudio estamos aportando datos anatómicos en relación al MPL en individuos brasileños adultos, evaluándolo con respecto a sus lugares de inserción.

Management of bilateral pterygoid myositis ossificans-like lesion in dogs.

Myositis ossificans (MO) and myositis ossificans-like lesions have been rarely described within the veterinary literature, and are even less common in the maxillofacial region. When MO affects the muscles of mastication, it can result in complete or partial inability to open the mouth. As with other conditions resulting in decreased or restricted mandibular range of motion, severe and potentially fatal sequelae such as difficulty with prehension, swallowing, and air exchange are possible. Diagnostic imaging is essential in achieving an accurate diagnosis and in formulating an appropriate treatment plan. In this "method" manuscript, we provide a detailed description of our approach to diagnosis and surgical management of MO-like lesions of the pterygoid muscles and describe our experience with two young French bulldogs.

The effects of botulinum toxin A injection on the lateral pterygoid muscle in patients with a painful temporomandibular joint click: a randomized clinical trial study.

BACKGROUND: Temporomandibular disorder (TMD) is the main cause of non-dental pain in orofacial area. The most common symptoms of TMD are joint pain, joint sound and limitation of jaw function. Botulinum toxin (BTX) injection is considered a potential treatment for TMD due to its pain-relieving properties and its ability to reduce muscle activity. Most of the studies are case series and further investigations are required to prove the efficacy of this treatment modality. Thus, in this study, we aimed to investigate the effect of BTX-A injection on the lateral pterygoid (LP) muscle and to evaluate its efficacy regarding TMD. MATERIALS AND METHODS: Thirty-eight patients (19 women and 19 men; mean age of 26.53 years) with painful unilateral temporomandibular joint click and LP muscle tenderness were enrolled in this study. They were divided into two groups; one received an extraoral BTX-A injection in the LP muscle, and the other received a placebo injection. Pain severity, jaw movements, click severity, and Helkimo index were recorded at the first visit, as well as one week, one month, and three months after the intervention. Data were analyzed using repeated-measures analysis of variance and t-tests. RESULTS: The results showed that click severity was not significantly different between the BTX-A and placebo groups (P = 0.07). Pain and Helkimo index decreased significantly in the BTX group (P = 0.00 and P = 0.006, respectively); however, there was no significant difference between the two groups (P = 0.22 and P = 1, respectively). There was a significant difference in lateral movements between the groups (P = 0.00) but not in protrusive movement (P = 0.095). CONCLUSIONS: It can be concluded that although some studies have stated that BTX injection can make the click sound disappear, in this study, we did not find a significant difference between the two groups. Furthermore, our results showed that click and pain severity decreased, but the difference was not statistically significant. Therefore, further studies with a higher dosage of BTX and more participants are recommended. Trial registration The local Ethics Committee of Shiraz University of Medical Sciences approved this research (IR.SUMS.REC. 01/10/2018 and IRCT20130521013406N3).

Volumetric Change in the Masseter and Lateral Pterygoid after Mandibular Setback.

In this study, we evaluated changes in the masseter and lateral pterygoid muscles in the prognathic mandible group after a mandibular setback by comparing the volume-to-length ratios. Preoperative and postoperative 1-year computed tomography was used to calculate the volume-to-length ratio of the lateral pterygoid and masseter muscle in 60 Korean individuals. Three-dimensional images were reconstructed, the results of which showed no significant differences in the volume-to-length ratios of the masseter and lateral pterygoid muscles after a mandibular setback (p > 0.05). This result was found for both vertical ramus osteotomy and sagittal split ramus osteotomy, and for both males and females. No significant differences in the volume-to-length ratio of the masseter and lateral pterygoid muscles were found up to 1 year after a mandibular setback. Therefore, this study can contribute to the prediction of soft-tissue profiles after mandibular setback.

Botulinum toxin injections in jaw-opening dystonia. The lateral pterygoid - maxillary artery problem.

It has been suggested that the variations in the trajectory of the maxillary artery (MA) near the lateral pterygoid muscle (LPM) play a critical role in Botulinum neurotoxin (BoNT) injections in patients with jaw-opening/deviation dystonia (JOD). In the case of a lateral course to the LPM, an extraoral injection entails risks of MA injury, pain, and hematoma. Previous reports suggest geographical differences in variations of the MA-LPM relationship. We aimed to determine these variations in Turkish individuals and highlight the need to establish a consensus on approach to LPM injections. In 284 individuals, contrast-enhanced magnetic resonance angiography (MRA) images were evaluated by two radiologists on both sides for the variations in the course of the MA in the infratemporal fossa. Images of 44 were excluded due to trauma, arteriovenous malformation, mass, surgery, and imaging artifacts. Of the included, 62.1% were female. In 480 evaluations of 240 individuals, the MA passed lateral to the LPM in 65.6% (n = 315). No sex difference was noted. In 51 individuals (21.3%), the MA course differed on the right and left sides (medial-lateral asymmetry). These results confirm that the lateral course of the MA is more frequent. In patients with JOD, the trajectory of the MA should be determined with imaging prior to extraoral BoNT injections. In the case of a lateral course, an intraoral approach seems to be safer to avoid a potential MA injury.