Sonographic elastography for evaluation of masseter muscle hardness

Evaluation of masticatory muscles in patients with different sagittal direction skeletal anomalies by ultrasonography and ultrasonographic elastography

OBJECTIVES

The aim of this study was to evaluated the masseter, anterior digastric and geniohyoid muscles of individuals with similar growth and developmental periods but different sagittal skeletal malocclusions using ultrasonography and ultrasonographic elastography and to make interclass assessments.

METHODS

In this study, ultrasonography and ultrasonographic elastography records of 30 Class I individuals (17 females, 13 males), 30 Class II individuals (14 females, 16 males), and 27 Class III individuals (12 females, 15 males) in the normodivergent and growth development period were used. The masseter, anterior digastric, and geniohyoid muscles of individuals were examined using ultrasonography and ultrasonographic elastography, and comparisons were made between the classes. Statistical analysis was accomplished by Mann Whitney U, One-way ANOVA, Kruskal Wallis H tests.

RESULTS

Interclass differences were found in ultrasonography and elastography measurements of the masseter muscle. However, no differences were observed in ultrasonography measurements of the auxiliary masticatory muscles, whereas differences were seen only in the geniohyoid muscle in elastography measurements among the classes (p < 0.05).

CONCLUSION

Individuals with different sagittal skeletal malocclusions during growth and development exhibited similar muscle sizes and elasticities, approximately close to each other.

Development and Validation of an Ultrasonography-Based Machine Learning Model for Predicting Outcomes of Bruxism Treatments

BACKGROUND AND OBJECTIVES

We aimed to develop a predictive model for the outcome of bruxism treatments using ultrasonography (USG)-based machine learning (ML) techniques. This study is a quantitative research study (predictive modeling study) in which different treatment methods applied to bruxism patients are evaluated through artificial intelligence.

MATERIALS AND METHODS

The study population comprised 102 participants with bruxism in three treatment groups: Manual therapy, Manual therapy and Kinesio Tape or Botulinum Toxin-A injection. USG imaging was performed on the masseter muscle to calculate muscle thickness, and pain thresholds were evaluated using an algometer. A radiomics platform was utilized to handle imaging and clinical data, as well as to perform a subsequent radiomics statistical analysis.

RESULTS

The area under the curve (AUC) values of all machine learning methods ranged from 0.772 to 0.986 for the training data and from 0.394 to 0.848 for the test data. The Support Vector Machine (SVM) led to excellent discrimination between bruxism and normal patients from USG images. Radiomics characteristics in pre-treatment ultrasound scans of patients, showing coarse and nonuniform muscles, were associated with a greater chance of less effective pain reduction outcomes.

CONCLUSIONS

This study has introduced a machine learning model using SVM analysis on ultrasound (USG) images for bruxism patients, which can detect masseter muscle changes on USG. Support Vector Machine regression analysis showed the combined ML models can also predict the outcome of the pain reduction.

Local alternating heat and cold stimulation affects hemodynamics and oxygenation in fatigued muscle tissue and autonomic nervous activity: a single-arm interventional study

BACKGROUND

Local alternating heat and cold stimulation as an alternative to contrast bath may cause intermittent vasoconstriction and vasodilation, inducing a vascular pumping effect and consequently promoting increased tissue blood flow and oxygenation. This study aimed to examine the effects of local alternating heat and cold stimulation, using a wearable thermal device, on the hemodynamics of fatigued muscle tissue and autonomic nervous activity.

METHODS

Twenty healthy individuals experienced fatigue in the periarticular muscles of the shoulder joint due to a typing task. Local alternating heat and cold stimulations were then applied to the upper trapezius muscle. Muscle hardness was measured using a muscle hardness meter, and muscle tissue hemodynamics and oxygenation were evaluated using near-infrared spectroscopy before and after the stimulation. Autonomic nervous activity was also evaluated using heart rate variability.

RESULTS

Alternating heat and cold stimulation decreased muscle hardness of the fatigued trapezius muscle from 1.38 ± 0.15 to 1.31 ± 0.14 N (P < 0.01). The concentration of total hemoglobin in the trapezius muscle tissue increased from - 0.21 ± 1.36 to 2.29 ± 3.42 µmol/l (P < 0.01), and the tissue hemoglobin oxygen saturation also increased from 70.1 ± 5.4 to 71.1 ± 6.0% (P < 0.05). Additionally, the heart rate variability parameter, which is an index of sympathetic nervous activity, increased from 3.82 ± 2.96 to 6.86 ± 3.49 (P < 0.01). A correlation was found between increased tissue hemoglobin oxygen saturation and increased parameters of sympathetic nervous activity (r = 0.50, P < 0.05).

CONCLUSIONS

Local alternating heat and cold stimulation affected the hemodynamic response in fatigued muscle tissue and autonomic nervous activity. This stimulation is more efficient than conventional contrast baths in terms of mobility and temperature control and has potential as a new versatile therapeutic intervention for muscle fatigue.

TRIAL REGISTRATION

UMIN-CTR (UMIN000040087: registered on April 7, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045710 . UMIN000040620: registered on June 1, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046359 ).

An investigation of the changes in mechanical properties of the orofacial and neck muscles between patients with myogenous and mixed temporomandibular disorders

OBJECTIVE

To investigate the possible changes in the mechanical properties of the orofacial and neck muscles in patients with temporomandibular disorders (TMD).

METHODS

The study included a total of 98 females. Females were divided into three groups as myogenous TMD, mixed TMD, and healthy controls. The frequency (indicator of muscle tone), stiffness, and decrement (related to muscle elasticity) values of the sternocleidomastoid, upper trapezius, cervical extensor, and masseter muscles were measured using a portable myotonometer.

RESULTS

The frequency, stiffness, and decrement values of the masseter muscle were higher in the mixed and myogenous TMD groups than those of the control group (p < 0.017). The mixed TMD group had higher frequency and stiffness values in the upper trapezius muscle compared with the control group (p < 0.017).

DISCUSSION

The results suggest that the mechanical properties of the oral and neck muscles may be affected in patients with TMD.

The role of scoliosis on temporomandibular joint disease: a cross-sectional study based on ultrasonography

AIM

To investigate the relationship between temporomandibular disorders (TMD) and the stomatognathic system and spine through a multidisciplinary approach, utilising ultrasound to assess the temporomandibular joint.

MATERIALS AND METHODS

Between October 2020 and January 2021, 50 patients aged 12-18 years with adolescent idiopathic scoliosis and 50 healthy individuals were enrolled. All participants underwent clinical examinations based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol. Additionally, ultrasound evaluations were performed of the temporomandibular joint and masseter muscles. Subsequently, the data from both groups were compared and analysed.

RESULTS

The mean age of participants was 14.69 ± 2.73 years in the scoliosis group (SG) and 14.68 ± 1.81 years in the control group (CG). Among scoliosis patients, a moderate negative correlation was observed between the Cobb angle (indicative of curvature severity) and mouth opening (p=0.023; r=-0.320). Furthermore, the incidence of TMD was significantly higher in the scoliosis group compared to the control group (p<0.001). Additionally, it was found that a 1-unit increase in joint space elastography value led to a 4.81-fold higher likelihood of diagnosing disc displacement with reduction (p=0.009; 95% CI: 1.47-15.73).

CONCLUSION

This pioneering study, the first of its kind to explore the connection between scoliosis and ultrasound-based temporomandibular joint screening, suggests that scoliosis may be a predisposing factor for TMD. Moreover, the present findings underscore the importance of joint elastography as a valuable quantitative tool in TMD diagnosis.

Determination of masseter and temporal muscle thickness by ultrasound and muscle hardness by shear wave elastography in healthy adults as reference values

OBJECTIVES

The purpose of this study is to prospectively investigate the reference values of masseter and temporal muscle thicknesses by ultrasonography and muscle hardness values by shear wave elastography in healthy adults.

METHODS

The sample of the study consisted of a total of 160 healthy individuals aged between 18 and 59, including 80 women and 80 men. By examining the right and left sides of each participant, thickness and hardness values were obtained for 320 masseter muscles and 320 temporal muscles in total.

RESULTS

The mean masseter muscle thickness was found to be 1.09 cm at rest and 1.40 cm in contraction. The mean temporal muscle thickness was found to be 0.88 cm at rest and 0.98 cm in contraction. The thickness values of the masseter and temporal muscles were significantly greater in the male participants than in the female participants (P < .001). While there were significant differences between the right and left masseter muscle thickness values at rest and in contraction, the values of the temporal muscles did not show a significant difference between the sides. While the resting hardness (rSWE) of the masseter muscle was transversally 6.91 kPa and longitudinally 8.49 kPa, these values in contraction (cSWE) were found, respectively, 31.40 and 35.65 kPa. The median temporal muscle hardness values were 8.84 kPa at rest and 20.43 kPa in contraction. Masseter and temporal muscle hardness values at rest and in contraction were significantly higher among the male participants compared to the female participants (P < .001).

CONCLUSION

In this study, reference values for the thickness and hardness of the masseter and temporal muscles are reported. Knowing these values will make it easier to assess pain in the masseter and temporal muscles and determine the diagnosis and prognosis of masticatory muscle pathologies by allowing the morphological and functional assessments of these muscles, and it will identify ranges for reference parameters.

Ultrasonographic evaluation of the masseter muscle in patients with temporomandibular joint degeneration

Purpose

Sonographic elastography can be used to evaluate the hardness of muscle tissue through the application of compression. Strain elastography gauges hardness through the comparison of echo sets before and after compression. This study utilized ultrasonography to measure the thickness and hardness of the masseter muscle in individuals with temporomandibular joint (TMJ) osteoarthritis.

Materials and Methods

This study included 40 patients who presented with joint pain and were diagnosed with TMJ osteoarthritis via diagnostic cone-beam computed tomography, along with 40 healthy individuals. The thickness and hardness of each individual's masseter muscle were evaluated both at rest and at maximum bite using ultrasonography. The Mann-Whitney U test and the chi-square test were employed for statistical analysis, with the significance level set at P<0.05.

Results

The mean thickness of the resting masseter muscle was 0.91 cm in patients with osteoarthritis, versus 1.00 cm in healthy individuals. The mean thickness of the masseter muscle at maximum bite was 1.28 cm in osteoarthritis patients and 1.36 cm in healthy individuals. The mean masseter elasticity index ratio at maximum bite was 4.51 in patients with osteoarthritis and 3.16 in healthy controls. Significant differences were observed between patients with osteoarthritis and healthy controls in both the masseter muscle thickness and the masseter elasticity index ratio, at rest and at maximum bite (P<0.05).

Conclusion

The thickness of the masseter muscle in patients with TMJ osteoarthritis was less than that in healthy controls. Additionally, the hardness of the masseter muscle was greater in patients with TMJ osteoarthritis.

Dynamic Quantitative Imaging of the Masseter Muscles in Bruxism Patients with Myofascial Pain: Could It Be an Objective Biomarker?

We aimed to investigate whether the collaboration of shear wave elastosonography (SWE) and B-mode ultrasonography (US) could be offered as diagnostic tools to assess the presence, severity, and progress of bruxism, as well as a biomarker for the effectiveness of treatment in daily clinical practice. The study was designed as a quantitative evaluation of the masseter muscles (MMs) of the clinically diagnosed bruxism patients suffering from myofascial pain and MMs of the healthy individuals. Clinical examinations were made according to the diagnostic criteria for temporomandibular disorders (DC/TMD), and pain was assessed using a visual analog scale (VAS). Painful MMs with VAS scores ≥ 4 were assigned to Group A, and healthy MMs were assigned to Group B. Also, the MMs of the painful bruxers were analyzed based on wearing occlusal splints. Group A was divided into two subgroups as splint users (Group AI) and non-users (Group AII). All the participants were scanned with dynamic US and SWE to quantify the size and stiffness of the MMs. Measurements of each muscle pair while the jaw is in a resting position (relaxation) and clenching position (contraction) were recorded. The significant differences in stiffness and thickness became visible in the relaxation state. Bruxism patients with myofascial pain had significantly harder and thinner MMs than healthy individuals. During the relaxation, the mean thickness and elasticity values were 9.17 ± 0.40 mm and 39.13 ± 4.52 kPa for Group A and 10.38 ± 0.27 and 27.73 ± 1.92 for Group B, respectively. Also, stiffer MMs were measured in Group AII (38.16 ± 3.61 kPa) than in Group AI (26.91 ± 2.13 kPa). In conclusion, the combination of SWE and US using a dynamic examination technique has the potential to be a valuable tool for the management of bruxism patients suffering from myofascial pain.

Effects of alternating heat and cold stimulation at different cooling rates using a wearable thermo device on shoulder muscle stiffness: a cross-over study

Background

A small, wearable thermo device that uses Peltier elements for programmed heat and cold stimulation has been developed recently and is expected to be applied in conventional contrast bath therapy. This study was aimed to examine improvements in trapezius muscle hardness and subjective symptoms resulting from alternating heat and cold stimulation, with different rates of cooling.

Methods

This cross-over study included four conditions. Twenty healthy young male individuals (age, 22.3 ± 4.5 years) participated in this study. These four interventions targeted the unilateral trapezius muscle of the dominant arm after a 15-min typing task. Specifically, heat and cold stimulations were applied at different ratios (the heating/cooling rate of 3:1, 3:2, and 3:3) or not applied. Each intervention was separated by at least one week. Skin temperature at the stimulation area was recorded using a data logger. Outcome measures included muscle hardness (measured using a portable tester) and subjective symptoms (muscle stiffness and fatigue). Each item was assessed at three time points: baseline, after typing, and after the intervention.

Results

Two-way analysis of variance with repeated measures found an interaction effect for muscle hardness between four conditions (3:1, 3:2, 3:3, and no) and three time points (p < 0.05). Only in the 3:1 condition were the post-intervention values lower than those after typing (p < 0.01). There was also an interaction effect for subjective muscle stiffness (p < 0.05); the values after the intervention in the 3:1 condition were lower than those after intervention in the no stimulation condition (p < 0.01). There was no significant relationship between changes in muscle hardness and changes in subjective symptoms in the 3:1 condition.

Conclusions

Our results demonstrate that alternating heat and cold stimulations with a different cooling rate could affect the degree of improvement in muscle hardness and subjective symptoms. In particular, the 3:1 condition has the possibility to improved muscle hardness within the condition and subjective muscle stiffness between conditions.

Trial registration

UMIN000040620. Registered 1 June 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046359

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05623-z.

Effects of alternating heat and cold stimulation using a wearable thermo-device on subjective and objective shoulder stiffness

BACKGROUND

Technological innovations have allowed the use of miniature apparatus that can easily control and program heat and cold stimulations using Peltier elements. The wearable thermo-device has a potential to be applied to conventional contrast bath therapy. This study aimed to examine the effects of alternating heat and cold stimulation (HC) using a wearable thermo-device on subjective and objective improvement of shoulder stiffness.

METHODS

Twenty healthy young male individuals (20.3 ± 0.6 years) participated in this study. The interventions were randomly conducted under four conditions, including HC, heat stimulation, cold stimulation, and no stimulation on their bilateral trapezius muscle, after a 30-min typing task. Each intervention was administered at least 1 week apart. The analyzed limb was the dominant arm. Muscle hardness was assessed using a portable muscle hardness meter, as well as the skin temperature over the stimulated area. After each condition, the participants were asked for feedback regarding subjective improvement in refreshed feelings, muscle stiffness, and muscle fatigue using an 11-point numerical rating scale.

RESULTS

With regard to muscle hardness, only the HC condition significantly decreased from 1.43 N to 1.37 N (d = 0.44, p < 0.05). Additionally, reduced muscle hardness in HC condition was associated with the degree of skin cooling during the intervention (cold max: r = 0.634, p < 0.01; cold change: r = -0.548, p < 0.05). Subjective improvement in refreshed feelings, muscle stiffness, and muscle fatigue was determined in the HC and heat stimulation conditions compared with the no stimulation condition (p < 0.01 and p < 0.05, respectively). Moreover, the HC condition showed significantly greater improvements in muscle stiffness and fatigue compared to the cold stimulation condition (p < 0.05).

CONCLUSIONS

The current study demonstrated that HC promoted not only better subjective symptoms, such as muscle stiffness and fatigue, but also lesser muscle hardness. Furthermore, an association was observed between the degree of skin temperature cooling and reduced muscle hardness during HC. Further investigations on the ratio and intensity of cooling should be conducted in the future to establish the optimal HC protocol for muscle stiffness or fatigue.

TRIAL REGISTRATION

UMIN000040620 . Registered 1 June 2020.

Quantitative sensory testing in patients with the muscle pain subtype of temporomandibular disorder: a systemic review and meta-analysis

OBJECTIVES

This meta-analysis aimed to evaluate quantitative sensory testing (QST) evidence for pain processing in patients with the muscle pain subtype of temporomandibular disorders (mTMD).

MATERIALS AND METHODS

A comprehensive systematic electronic search strategy was performed in online literature databases. All full-text observational studies published up to July 2021 with the aim of investigating pain sensitization in humans with mTMD using QST measures were eligible for inclusion. Meta-analysis of QST data was performed using a random effects model, which included results comparing patients with mTMD to healthy controls, and standard mean difference (SMD) results were analyzed.

RESULTS

Twelve studies with 732 participants (371 patients with mTMD and 361 healthy controls) were analyzed following screening and quality appraisal. Compared with healthy controls, patients with mTMD had significantly lower pressure pain threshold (SMD - 1.10, 95% confidence interval [CI] - 1.52 to - 0.68) with high heterogeneity (Tau2 = 0.61, I2 = 86%), and significantly lower mechanical pain threshold (SMD - 0.64, 95% CI - 0.95 to - 0.32) with no heterogeneity (Tau2 = 0.00, I2 = 0%). No difference was observed in the cold pain threshold (SMD 0.16, 95% CI - 0.13 to 0.45), heat pain threshold (SMD - 0.13, 95% CI - 0.40 to 0.15), and wind-up ratio (SMD 0.63, 95% CI - 0.11 to 1.38) between patients with mTMD and healthy controls. Other QST parameters were also discussed.

CONCLUSIONS

The study results suggest that the pain processing of deep tissues is likely sensitized in mTMD and calls for more QST studies with standard procedures to reduce inter-study heterogeneity.

CLINICAL RELEVANCE

The major findings of this meta-analysis support using PPT to examine the pain processing in patients with mTMD in clinical scenario.

Comparison of Kinesio Taping and manual therapy in the treatment of patients with bruxism using shear-wave elastography-A randomised clinical trial

BACKGROUND

Bruxism is significantly associated with craniofacial pain, feeling of stiffness or fatigue of the jaw and neck pain. Various physiotherapeutic strategies are used in the treatment of bruxism; however, it is not clear which method leads to greater decrease in pain.

OBJECTIVE

The aim of this study is to compare the effects of two physiotherapy methods (manual therapy [MT] and Kinesio taping with manual therapy [KTMT]) in patients with bruxism.

METHODS

Patients were randomised into MT or KTMT groups. Evaluations were performed at baseline and following 4 weeks of physiotherapy. Muscle thickness and stiffness were assessed via shear wave elastography; pain thresholds were evaluated using algometer. Sleep quality was assessed using Pittsburgh Sleep Quality Index, and quality of life was assessed with Likert scales regarding the associated symptoms.

RESULTS

Significant decreases were found in muscle stiffness, pain threshold, sleep quality and quality of life (P < .05) in both MT and KTMT groups. Pain in bilateral temporalis and right occipital region of the trapezius muscle decreased more in the KTMT group compared with the MT group (P < .05). No significant differences in muscle thickness (P > .05) were found in either of the groups.

CONCLUSION

Both MT and KTMT methods were effective in the treatment of bruxism. Kinesio Tape used in conjunction with MT has additionally decreased jaw pain and temporal region pain compared with MT intervention only. Therefore, if jaw pain is the primary complaint of a patient, our results recommend including Kinesio Tape application in the physiotherapeutic treatment program.

Quantitative assessment of temporomandibular disc and masseter muscle with shear wave elastography

PURPOSE

To assess the normal stiffness values of temporomandibular joint disc (TMJ) and masseter muscle by shear wave elastography (SWE) in a healthy adult population. This may be helpful in diagnosing and understanding the mechanism of temporomandibular disorders (TMD).

METHODS

This prospective study evaluated a total of 160 healthy adult volunteers (77 males, 83 females). The stiffness values of anterior, intermediate and posterior parts of the TMJ disc and masseter muscle were measured. Study cohort was classified into four groups based on age. Additionally, we investigated the changes in mean shear wave elasticity (kPa) and shear wave velocity(m/s) values of disc parts and masseter muscle in closed and open mouth positions, and the correlation of these SWE values with age and gender.

RESULTS

Mean stiffness values of the disc were 37.02 ± 23.75 kPa and 3.28 ± 1.09 m/s in the anterior part, 30.47 ± 18.89 kPa and 2.97 ± 1.04 m/s in the intermediate part, 22.61 ± 13.97 kPa and 2.55 ± 0.88 m/s in the posterior part. Stiffness values showed significant decrease in the posterior part compared to the rest of the disc both in males and females. No significant differences in mean stiffness values of masseter muscle related to mouth position, age or gender.

CONCLUSION

This study provides the normative quantitative elasticity values of disc and masseter muscle which could be a reference point for upcoming studies. Disc elasticity values are higher in women than men. Maybe this is one of the reason why TMD is more common in women. TMJ disc stiffness was significantly lower in the posterior part. SWE is a useful imaging method that can be used with routine ultrasonography in evaluation of the TMJ disc and masticatory muscles .

An Artificial Intelligence Hypothetical Approach for Masseter Muscle Segmentation on Ultrasonography in Patients With Bruxism

Aim:

The present study is aimed to assess the segmentation success of an artificial intelligence (AI) system based on the deep convolutional neural network (D-CNN) method for the segmentation of masseter muscles on ultrasonography (USG) images.

Materials and Methods:

This retrospective study was carried out by using the radiology archive of the Department of Oral and Maxillofacial Radiology of the Faculty of Dentistry in Ankara University. A total of 195 anonymized USG images were used in this retrospective study. The deep learning process was performed using U-net, Pyramid Scene Parsing Network (PSPNet), and Fuzzy Petri Net (FPN) architectures. Muscle thickness was assessed using USG by manual segmentation and measurements using USG’s software. The neural network model (CranioCatch, Eskisehir-Turkey) was then used to determine the muscles, following automatic measurements of the muscles. Accuracy, ROC area under the curve (AUC), and Precision-Recall Curves (PRC) AUC were calculated in the test dataset and compare a human observer and the AI model. Manual segmentation and measurements were compared statistically with AI ( P < .05). The Mann–Whitney U test was used to analyze whether there is a statistically significant difference between the predicted values and the actual values.

Results:

The AI models detected and segmented all test muscle data for FPN and U-net, while only two cases of muscles were not detected by PSPNet (false negatives). Accuracies of FPN, PSPNet, and U-net were estimated as 0.985, 0.947, and 0.969, respectively. Receiver operating characteristic scores of FPN, PSPNet, and U-net were estimated as 0.977, 0.934, and 0.969, respectively. The D-CNN measurements of the muscles were similar to manual measurements. There was no significant difference between the two measurement methods in three groups ( P > .05).

Conclusion:

The proposed AI system approach for the analysis of USG images seems to be promising for automatic masseter muscle segmentation and measurement of thickness. This method can help surgeons, radiologists, and other professionals such as physical therapists in evaluating the time correctly and saving time for diagnosis.

Electromyographic, Ultrasonographic, and Ultrasound Elastographic Evaluation of the Masseter Muscle in Class III Patients Before and After Orthognathic Surgery

PURPOSE

The aim of this study was to examine changes in the electromyographic activity, thickness, width, and hardness of the masseter muscle from before to after orthognathic surgery.

MATERIAL AND METHODS

The study included 15 patients with Class III dentofacial deformities who were treated with combined orthodontic and orthognathic surgery. Fifteen individuals with normal occlusion and no signs or symptoms of temporomandibular joint dysfunction were used as controls. All records were obtained bilaterally in the study group before surgery (T1), at 3 months after surgery (T2), and in the control group (CG) while at rest and in maximum voluntary contraction (MVC).

RESULTS

There was no difference in resting masseter muscle activity between T1, T2, and CG. Resting thickness and width of the masseter muscle did not differ significantly between T1 and T2. MVC masseter muscle activity and thickness increased significantly and width decreased significantly from T1 to T2 but did not reach CG values. Muscle hardness increased from T1 to T2.

CONCLUSIONS

The authors' findings indicate that despite improved muscle activity and dimensions, postoperative 3 months is still early period for adaptation of the masseter muscles to the new occlusion and skeletal morphology.

Reliability of Trapezius Muscle Hardness Measurement: A Comparison between Portable Muscle Hardness Meter and Ultrasound Strain Elastography

Prolonged computer work and smartphone use can cause stiffness of the neck and shoulder muscles, including the trapezius muscle. Hence, muscle hardness quantification is clinically beneficial. The present study aimed to examine the reliability of trapezius muscle hardness measurement using a portable muscle hardness meter and ultrasound strain elastography. Overall, 20 healthy young men participated in this study. Prior to measurement, the participant’s subjective symptoms, particularly shoulder muscle stiffness, were rated using an 11-point verbal scale. Furthermore, hardness of the right and left upper trapezius muscles was assessed. In the strain elastography assessment, muscle hardness was evaluated using strain ratio. Results showed that, in quantifying upper trapezius muscle hardness, both portable muscle hardness meter and strain elastography had an excellent intra-tester reliability (>0.9). However, the correlation coefficients between muscle hardness values assessed using a muscle hardness meter and those evaluated with strain elastography did not significantly differ, and the scores for subjective shoulder stiffness did not correspond to muscle hardness values. Therefore, the hardness of the trapezius muscle does not directly reflect the subjective shoulder stiffness. Future studies should thoroughly examine the location of the shoulder stiffness, and check whether it is accompanied by local pain or tenderness.

Methods of Masseter and Temporal Muscle Thickness and Elasticity Measurements by Ultrasound Imaging: A Literature Review

BACKGROUND

The positive correlation between changes in the morphology of masseter and temporal muscles and some disorders, inclines diagnosticians to search for an effective method of assessing muscle thickness and elasticity. Ultrasound imaging, as a relatively simple and cheap method, seems to be a useful diagnostic tool.

OBJECTIVE

The aim of this study was to present the existing ultrasound imaging methods in the assessment of the elasticity and thickness of the masseter and temporal muscles.

METHODS

The literature review has been done with a focus on the accurate description of the masseter and/or temporal muscle examination by ultrasonography imaging methods. Articles were categorized into two groups. The first group included articles in which muscle thickness was assessed by ultrasound imaging. The second group concerned the elasticity aspect of mentioned muscles.

RESULTS

It is difficult to achieve an objective protocol of masseter and temporal thickness assessment by ultrasonography and there is no method that has been fully verified in terms of reliability. The shear-wave sonoelastography revealed higher-level reliability of masseter muscle elasticity than strain sonoelastography. During the shear-wave sonoelastography, the effect of scan plane in relation to masseter muscle pennation and the day-to-day variation were statistically significant. With regard to elasticity of temporal muscle, further research is needed.

CONCLUSION

This review has shown that there is a limited number of methods for masseter and temporal muscle thickness and elasticity measurements by ultrasonography. All procedures (methods) were not fully verified in terms of reliability and agreement. Thus, it is still necessary to develop standardized procures to assess thickness and elasticity of the masseter and temporal muscles with appropriate reliability and accuracy.

Strain Elastosonography Measurement in Patients with Primary Muscle Tension Dysphonia Compared with Healthy Speakers: A Pilot Study

OBJECTIVES

The purpose of this study was to investigate real-time elastosonography (RTE) to measure strain of the (para)laryngeal muscles in patients with primary muscle tension dysphonia (MTD) and healthy speakers.

STUDY DESIGN

This is a cross-sectional study.

METHODS

Ten patients with primary MTD (37.8 ± 10.53 years) and 10 healthy speakers (36.9 ± 9.8 years) participated. Participants were diagnosed as MTD patient or healthy via voice history, voice self-assessment, perceptual voice evaluation, laryngeal palpation, and videostroboscopy. Then, RTE was performed to extract strain index (SI) and strain ratio (SR) for all participants. The RTE was utilized for the suprahyoid, thyrohyoid, and the cricothyroid muscles, both in right and left sides during rest, /a/, and /i/ prolongations. To study the effect of group, task, and interactive effect on the SI and SR, two-way repeated-measures analysis of variance was performed.

RESULTS

The effect of group on the SI was significant for the right cricothyroid (P ˂ 0.001). Significant effect of group on the SR obtained for the right suprahyoid, left thyrohyoid, and right cricothyroid (P < 0.05). Moreover, the only muscle whose SR was significantly affected by task was the left suprahyoid (P < 0.05). Compared to healthy speakers, the interactive effect was significantly lower in SI for the left cricothyroid, and higher in SR for both the right suprahyoid and left cricothyroid in patients (P < 0.05).

CONCLUSIONS

The RTE can discriminate patients with primary MTD from healthy subjects in some laryngeal muscles, especially suprahyoid and cricothyroid. It may be regarded as a clinical instrument in the assessment of MTD in future. Further studies with bigger sample size are recommended.

Great potential of ultrasound elastography for the assessment of the masseter muscle in patients with temporomandibular disorders. A systematic review

Objective:

To summarize the available evidence on the use of elastography in the assessment of the masseter muscle in healthy individuals and patients with masseter muscle disorders.

Methods:

Systematic literature review has been performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

Results:

16 of 142 studies identified were analyzed. Elastography was used in seven studies. Heterogeneity was observed in terms of study protocols, devices, patients, units of measure, and results. Elasticity values showed a correlation between the left and right masseter muscle side in healthy people, but not in patients with temporomandibular disorders (TMDs). Elasticity values increased in TMD and were correlated with the severity of TMD symptoms. Phantom studies proved the high reliability of elastography.

Conclusion:

Elastography is a promising tool for the assessment of the masseter muscle elasticity, but the evidence is insufficient. Studies on larger groups are needed to determine the accuracy of elastography to characterize masticatory muscle disorders.

Ultrasound elastography as a potential diagnostic aid in oral submucous fibrosis

Background

Oral submucous fibrosis (OSMF) is a well-recognized "potentially malignant" disorder. It mostly affects the productive population of young adults and adolescents. The diagnosis of oral submucous fibrosis is primarily clinical and subjective. The only objective diagnostic method for OSMF is tissue biopsy. This study was conducted to find the potential use of ultrasound elastography to objectively quantify the clinical presentation in accordance with severity of the clinical condition in OSMF.

Materials and Methods

The study sample consisted of 27 clinically diagnosed and staged participants with OSMF. Transcutaneous ultrasonography was done by a single operator on GE Logiq E9 machine with a 6-15 MHz linear matrix probe. Color-coded scheme was used to qualitatively grade the eight different zones of oral mucosa with the use of stress-strain elastography. The grades ranged from 0 to 5, where 0 represented artifacts and color range from red to blue corresponded to varying degree of increasing tissue stiffness. Clinical stage 1, 2, and 3 corresponded to mouth opening of >30 mm, 20-30 mm, and <20 mm, respectively. The summative elastography score range as follows: 8-10, 11-14, and ≥15 represented the respective degree of tissue stiffness from soft, mild stiff to severe stiff.

Results

The results obtained by Pearson's correlation between the elastographic grading and clinical grading came out to be 0.007, and it was highly significant. The sensitivity and specificity of the diagnostic method were 90.9% and 20%, respectively.

Conclusion

The advantages of ultrasound elastography as a diagnostic tool over the subjective clinical method of diagnosis and staging of OSMF looks promising. Further studies should be conducted with a suitable specific transducer probe and with quantitative diagnostic elastography method.

Masseter muscle thickness and elasticity in periodontitis

This study aimed to compare the thickness and elasticity of the masseter muscle between patients with gingivitis and patients with periodontitis. A total of 124 patients (63 gingivitis, 61 chronic periodontitis) were recruited at the start of the study, but only 84 patients were declared as final participants. Patients were divided into two groups: (1) patients suffering from gingivitis and (2) those with generalized chronic periodontitis. Clinical (PI, plaque index; GI, gingival index; PD, probing depth; CAL, clinical attachment loss; and BOP, bleeding on probing scores) and ultrasonographic (thickness and elasticity of the masseter muscle) measurements of periodontitis were performed. There were no significant differences in gender, age, body mass index, education status, income level, or marital status between the two groups (P > 0.05). The mean age ± SD for the gingivitis and periodontitis groups was 39.5 ± 10.8 years and 44.8 ± 8.8 years, respectively. There were significant differences between the two groups in the number of PI, GI, PD, CAL, and BOP scores. There were significant differences between the two groups when thickness of masseter during contraction and at rest was taken into account. The gingivitis group had significantly thicker masseter during both contraction and rest. On the other hand, when the elasticity of the masseter was evaluated, there were no significant differences found between the two groups and two sides for each group. Masseter muscle thickness in the periodontitis group was found to be decreased compared with that in the gingivitis group. Furthermore, loss of periodontal tissues due to periodontitis reduces the masticatory ability.

Assessing the elastic properties of skeletal muscle and tendon using shearwave ultrasound elastography and MyotonPRO

The purposes of this study were to compare Young’s modulus values determined by shear wave ultrasound elastography (SWUE) with stiffness index obtained using a hand-held MyotonPRO device on the resting stiffness of gastrocnemius muscle belly and Achilles tendon; and to examine the test-retest reliability of those stiffness measurement using hand-held MyotonPRO. Twenty healthy volunteers participated in the study. The measurement values of muscle and tendon was determined in dominant legs. Each marker point was assessed using MyotonPRO and SWUE, respectively. Intra-operator reliability of MyotonPRO was established in 10 of the subjects. The correlation coefficients between the values of muscle and tendon stiffness indices determined by MyotonPRO and SWUE were calculated. Significant correlations were found for muscle and tendon stiffness and Young’s modulus ranged from 0.463 to 0.544 (all P < 0.05). The intra-operator reliability ranged from good to excellent (ICC_(3,1) = 0.787~0.928). These results suggest that the resting stiffness of gastrocnemius muscle belly and Achilles tendon measured by MyotonPRO is related to the Young’s modulus of those quantified by SWUE. The MyotonPRO shows good intra-operator repeatability. Therefore, the present study shows that MyotonPRO can be used to assess mechanical properties of gastrocnemius muscle belly and Achilles tendon with a resting condition.

Muscle hardness and masticatory myofascial pain: Assessment and clinical relevance

The impression of increased muscle hardness in painful muscles is commonly reported in the clinical practice but may be difficult to assess. Therefore, the aim of this review was to present and discuss relevant aspects regarding the assessment of muscle hardness and its association with myofascial temporomandibular disorder (TMD) pain. A non-systematic search for studies of muscle hardness assessment in patients with pain-related TMDs was carried out in PubMed, Cochrane Library, Embase and Google Scholar. Mechanical devices and ultrasound imaging (strain and shear wave elastography) have been consistently used to measure masticatory muscle hardness, although an undisputable reference standard is yet to be determined. Strain elastography has identified greater masseter hardness of the symptomatic side in patients with unilateral myofascial TMD pain when compared to the contralateral side and healthy controls (HC). Likewise, shear wave elastography has shown greater masseter elasticity modulus in patients with myofascial TMD pain when compared to HC, which may be an indication of muscle hardness. Although assessment bias could partly explain these preliminary findings, future randomised controlled trials are encouraged to investigate this relationship. This qualitative review indicates that the muscle hardness of masticatory muscles is still a rather unexplored field of investigation with a good potential to improve the assessment and potentially also the management of myofascial TMD pain. Nonetheless, the current evidence in favour of increased hardness in masticatory muscles in patients with myofascial TMD pain is weak, and the pathophysiological importance and clinical usefulness of such information remain unclear.

Change detection technique for muscle tone during static stretching by continuous muscle viscoelasticity monitoring using wearable indentation tester

Static stretching is widely performed to decrease muscle tone as a part of rehabilitation protocols. Finding out the optimal duration of static stretching is important to minimize the time required for rehabilitation therapy and it would be helpful for maintaining the patient's motivation towards daily rehabilitation tasks. Several studies have been conducted for the evaluation of static stretching; however, the recommended duration of static stretching varies widely between 15-30 s in general, because the traditional methods for the assessment of muscle tone do not monitor the continuous change in the target muscle's state. We have developed a method to monitor the viscoelasticity of one muscle continuously during static stretching, using a wearable indentation tester. In this study, we investigated a suitable signal processing method to detect the time required to change the muscle tone, utilizing the data collected using a wearable indentation tester. By calculating a viscoelastic index with a certain time window, we confirmed that the stretching duration required to bring about a decrease in muscle tone could be obtained with an accuracy in the order of 1 s.

A critical overview of the current myofascial pain literature - June 2017

We would like to welcome Dr. Li-Wei Chou, MD, PhD as our newly appointed contributing author. Dr. Chou is Assistant Professor at China Medical University in Taichung, Taiwan and he has an impressive publication record with many research studies and book chapters. The current overview includes several articles comparing dry needling (DN) to acupuncture with sharply contrasting points of view. Several basic studies shed further light on the nature of myofascial pain, myalgia, fascia and examination techniques, such as sonoelastography. Neuroimaging studies demonstrated microstructural abnormalities in brain gray matter of chronic myofascial pain patients, which is an important new finding. As usual, many manual TrP papers and DN papers were published in the past several months.

Magnetic resonance and sonographic imagings of masticatory muscle myalgia in temporomandibular disorder patients

This article reviews recently published studies investigating the MRI and sonographic diagnosis of masticatory muscle myalgia in temporomandibular disorder patients. The MRI and sonographic features of muscle after treatment are also discussed. Literature published within the last 15 years was obtained from the PubMed database using the following Mesh terms: magnetic resonance imaging (MRI) or sonography, masticatory muscle pain, and treatment. MRI and sonography enable accurate visualization and evaluation of the masticatory muscles, thereby increasing our understanding of pathology and cause of pain associated with these muscles. Although therapeutic efficacy is often evaluated based on clinical findings, MR and sonographic imaging studies may also be valuable.

Sonoelastography in the musculoskeletal system: Current role and future directions

Ultrasound is an essential modality within musculoskeletal imaging, with the recent addition of elastography. The elastic properties of tissues are different from the acoustic impedance used to create B mode imaging and the flow properties used within Doppler imaging, hence elastography provides a different form of tissue assessment. The current role of ultrasound elastography in the musculoskeletal system will be reviewed, in particular with reference to muscles, tendons, ligaments, joints and soft tissue tumours. The different ultrasound elastography methods currently available will be described, in particular strain elastography and shear wave elastography. Future directions of ultrasound elastography in the musculoskeletal system will also be discussed.

Shear-wave sonoelastography for assessing masseter muscle hardness in comparison with strain sonoelastography: study with phantoms and healthy volunteers

Objectives Shear-wave sonoelastography is expected to facilitate low operator dependency, high reproducibility and quantitative evaluation, whereas there are few reports on available normative values of in vivo tissue in head and neck fields. The purpose of this study was to examine the reliabilities on measuring hardness using shear-wave sonoelastography and to clarify normal values of masseter muscle hardness in healthy volunteers. Methods Phantoms with known hardness ranging from 20 to 140 kPa were scanned with shear-wave sonoelastography, and inter- and intraoperator reliabilities were examined compared with strain sonoelastography. The relationships between the actual and measured hardness were analyzed. The masseter muscle hardness in 30 healthy volunteers was measured using shear-wave sonoelastography.

RESULTS

The inter- and intraoperator intraclass correlation coefficients were almost perfect. Strong correlations were seen between the actual and measured hardness. The mean hardness of the masseter muscles in healthy volunteers was 42.82 ± 5.56 kPa at rest and 53.36 ± 8.46 kPa during jaw clenching.

CONCLUSIONS

The hardness measured with shear-wave sonoelastography showed high-level reliability. Shear-wave sonoelastography may be suitable for evaluation of the masseter muscles.

Comparison Between Neck and Shoulder Stiffness Determined by Shear Wave Ultrasound Elastography and a Muscle Hardness Meter

The goals of this study were to compare neck and shoulder stiffness values determined by shear wave ultrasound elastography with those obtained with a muscle hardness meter and to verify the correspondence between objective and subjective stiffness in the neck and shoulder. Twenty-four young men and women participated in the study. Their neck and shoulder stiffness was determined at six sites. Before the start of the measurements, patients rated their present subjective symptoms of neck and shoulder stiffness on a 6-point verbal scale. At all measurement sites, the correlation coefficients between the values of muscle hardness indices determined by the muscle hardness meter and shear wave ultrasound elastography were not significant. Furthermore, individuals' subjective neck and shoulder stiffness did not correspond to their objective symptoms. These results suggest that the use of shear wave ultrasound elastography is essential to more precisely assess neck and shoulder stiffness.

Two-dimensional ultrasound and ultrasound elastography imaging of trigger points in women with myofascial pain syndrome treated by acupuncture and electroacupuncture: a double-blinded randomized controlled pilot study

Chronic pain has been often associated with myofascial pain syndrome (MPS), which is determined by myofascial trigger points (MTrP). New features have been tested for MTrP diagnosis. The aim of this study was to evaluate two-dimensional ultrasonography (2D US) and ultrasound elastography (UE) images and elastograms of upper trapezius MTrP during electroacupuncture (EA) and acupuncture (AC) treatment. 24 women participated, aged between 20 and 40 years (M ± SD = 27.33 ± 5.05) with a body mass index ranging from 18.03 to 27.59 kg/m2 (22.59 ± 3.11), a regular menstrual cycle, at least one active MTrP at both right (RTPz) and left trapezius (LTPz) and local or referred pain for up to six months. Subjects were randomized into EA and AC treatment groups and the control sham AC (SHAM) group. Intensity of pain was assessed by visual analogue scale; MTrP mean area and strain ratio (SR) by 2D US and UE. A significant decrease of intensity in general, RTPz, and LTPz pain was observed in the EA group (p = 0.027; p < 0.001; p = 0.005, respectively) and in general pain in the AC group (p < 0.001). Decreased MTrP area in RTPz and LTPz were observed in AC (p < 0.001) and EA groups (RTPz, p = 0.003; LTPz, p = 0.005). Post-treatment SR in RTPz and LTPz was lower than pre-treatment in both treatment groups. 2D US and UE effectively characterized MTrP and surrounding tissue, pointing to the possibility of objective confirmation of subjective EA and AC treatment effects.

Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography

OBJECTIVES

To verify the use of a single coupling agent as a reference to obtain the elasticity index (EI) ratios and to investigate the EI ratios of the masseter muscles of healthy volunteers.

METHODS

Muscle phantoms with known elasticity (20, 40 and 60 kPa in the Young's modulus) were examined by strain-type sonoelastography using a coupling agent as the reference. Eight examiners tested soft (with 7 kPa) and hard (with 40 kpa) reference coupling agents separately. The correlation coefficients were determined between the EI ratio and Young's modulus of muscle phantoms. The interclass correlation coefficients were calculated for inter- and intraexaminer agreement.

RESULTS

Strong correlations were found between the EI ratios and Young's modulus for both soft and hard references. The variations of the EI ratios were larger with soft coupling agents than those with hard coupling agents, and they increased in phantoms with 60 kPa elasticity. There were no differences in the EI ratios of the masseter muscle at rest between males and females or between the right and left sides. The ratio increased during clenching.

CONCLUSIONS

The hard reference coupling agent was suitable for obtaining EI ratio of the masseter muscle. No differences were found in the EI ratios of the masseter muscle either between sexes or between the right and left sides at rest, and the ratios increased with the widening of their variations during clenching.

Can sonographic features be efficacy predictors of robotic massage treatment for masseter and temporal muscle in patients with temporomandibular disorder with myofascial pain?

OBJECTIVE

The aim of this study was to detect sonographic predictors for the efficacy of massage treatment of masseter and temporal muscle in temporomandibular disorders (TMDs) patients with myofascial pain.

METHODS

Thirty-seven TMD patients with myofascial pain (6 men and 31 women, a median age of 45 years) were enrolled. An oral rehabilitation robot massaged the patient's masseter and temporal muscles with a standard massage pressure of 10 N for 16 min. The standard treatment protocol was set five sessions every 2 weeks. The median total duration of treatment was 9.5 weeks. Efficacy of treatment was evaluated based on maximum mouth opening and visual analog scale scores of muscle pain and daily life impediments. The intramuscular echogenic bands and elasticity index ratios of the masseter muscles were evaluated on sonographic or sonoelastographic images obtained before treatment and after the third and last treatment sessions.

RESULTS

The sonographic features detected different changes after the third treatment session between the therapy-effective and therapy-ineffective groups: in the therapy-effective group, the frequency of visibility of the distinct echogenic bands increased, and the elasticity index ratio decreased.

CONCLUSION

Sonographic features after the third treatment session may be useful as predictors of therapeutic efficacy.

Intramuscular changes of soft and hard areas after low-level static contraction of the masseter muscle and the correlations with muscle hardness and increase in water content: evaluations with sonographic elastography and magnetic resonance imaging

OBJECTIVES

To investigate the intramuscular changes on sonographic elastography (SE) after low-level static contraction of the masseter muscle, and to clarify the relationship with the total hardness and edematous change.

STUDY DESIGN

Ten healthy volunteers performed sustained bilateral biting at 20% of maximal voluntary contraction for 10 min. The SE and magnetic resonance (MR) scans of the masseter muscles were performed before, immediately after, and 10 min after exercise. The masseter muscle elasticity index (MEI) ratio, muscle thickness, and intramuscular soft and hard areas distribution were evaluated on SE images. The signal to noise ratio (SNR), indicating the water content, was measured on MR images.

RESULTS

The soft area ratio showed significant correlations with the water content expressed as SNR. The hard area ratio showed significant correlations with the total muscle hardness expressed as the MEI ratio.

CONCLUSION

Intramuscular soft and hard areas could be used both clinically and experimentally.

Effects of compression force on elasticity index and elasticity ratio in ultrasound elastography

OBJECTIVES

The purpose of this study was to investigate the relationship between compression force and hardness values in ultrasound elastography.

METHODS

Ultrasound elastography was performed using an elastography phantom, comprising inclusions with different elasticities and echogenicities. The compression force was set to approximately 100 gw (light force) and approximately 500 gw (heavy force). The elasticity index (EI) of the inclusion was measured. The EI was a relative hardness value of a structure within an elastographic image. Similarly, the EI of the background was measured as a reference. The elasticity ratio (ER) was calculated as the EI of the inclusion divided by the EI of the reference.

RESULTS

The hardness of the phantom could be discerned with both the EI and ER, regardless of the compression force. The EI and ER with heavy force tended to be higher than those with light force, but the difference was not significant. A strong correlation was observed between the EI and ER of soft structures, whereas the correlation between the EI and ER of hard structures was weak, and the ER values varied widely.

CONCLUSIONS

The EI offers potential as a good indicator for assessing the hardness.