Quantitative ultrasound of the tongue and submental muscles in children and young adults

Assessing the oral and suprahyoid muscles in healthy adults using muscle ultrasound to inform the swallowing process: a proof-of-concept study

The oral and suprahyoid muscles are responsible for movements of swallowing. Our study aimed to determine the reproducibility of static and dynamic measurements of these muscles using bedside ultrasound equipment. Forty healthy participants were recruited prospectively. Primary outcomes were evaluation of mass measurements of the anterior bellies of the digastric, mylohyoid, geniohyoid and tongue in B-mode ultrasound. Secondary outcomes were evaluation of geniohyoid muscle layer thickness and function using M-mode. Muscle mass measurements demonstrated little within-participant variability. Coefficient of Variance (CoV) across muscles were: anterior belly digastric (5.0%), mylohyoid (8.7%), geniohyoid (5.0%) and tongue (3.2%). A relationship between sex (r2 = 0.131 p = 0.022) was demonstrated for the geniohyoid muscle, with males having higher transverse Cross Sectional Area (CSA) (14.3 ± 3.6 mm vs. 11.9 ± 2.5 mm, p = 0.002). Tongue size was correlated with weight (r2 = 0.356, p = 0.001), height (r2 = 0.156, p = 0.012) and sex (r2 = 0.196, p = 0.004). Resting thickness of the geniohyoid muscle layer changed with increasing bolus sizes (f = 3.898, p = 0.026). Velocity increased with bolus size (p =  < 0.001, F = 8.974). However swallow time and slope distance did not, potentially influenced by higher coefficients of variation. Oral and suprahyoid muscle mass are easily assessed using bedside ultrasound. Ultrasound may provide new information about muscle mass and function during swallowing.

Defining the Shape of the Mylohyoid Muscle: A Morphometric Imaging Study

OBJECTIVES

Implantable hypoglossal nerve stimulation (HNS) therapy is an evolving therapeutic alternative for patients with refractory obstructive sleep apnea (OSA). The muscular anatomy of this region has implications for surgical access through this zone as well as positioning and anchoring of hardware in this area. The purpose of this study was to radiologically describe the topography of the mylohyoid muscle and adjacent structures across a wide age spectrum.

METHODS

We retrospectively evaluated computed tomography scans of the neck in 102 patients who were imaged for reasons unrelated to the floor of mouth or submental space. Patients with prior surgery or pathology in the area of interest were excluded. Fourteen relevant muscle measurements were made on a midline sagittal image and a coronal image positioned at the midpoint between the hyoid bone and the mandible.

RESULTS

We included 49 men and 53 women with an average age of 44 years (range 19-70). The average mylohyoid length was 42 mm; the average distance between the anterior digastric bellies was 17 mm. The average angle of the central mylohyoid was 174° in the sagittal plane and 164° in the coronal plane. Several measurements were significantly correlated with patient age, including the angle measurements and the distance between the digastric muscles. Aberrant digastric anatomy was common.

CONCLUSIONS

The mylohyoid muscle has multiple radiologically distinct segments with predictable curvatures. An understanding of submental muscular anatomy, along with its variability between patients, may be beneficial to the development of bilateral implantable neurostimulation technology for the treatment of refractory OSA.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:2970-2975, 2024.

The Pathway from Anatomy and Physiology to Diagnosis: A Developmental Perspective on Swallowing and Dysphagia

Dysphagia results from diverse and distinct etiologies. The pathway from anatomy and physiology to clinical diagnosis is complex and hierarchical. Our approach in this paper is to show the linkages from the underlying anatomy and physiology to the clinical presentation. In particular, the terms performance, function, behavior, and physiology are often used interchangeably, which we argue is an obstacle to clear discussion of mechanism of pathophysiology. We use examples from pediatric populations to highlight the importance of understanding anatomy and physiology to inform clinical practice. We first discuss the importance of understanding anatomy in the context of physiology and performance. We then use preterm infants and swallow-breathe coordination as examples to explicate the hierarchical nature of physiology and its impact on performance. We also highlight where the holes in our knowledge lie, with the ultimate endpoint of providing a framework that could enhance our ability to design interventions to help patients. Clarifying these terms, and the roles they play in the biology of dysphagia will help both the researchers studying the problems as well as the clinicians applying the results of those studies.

Muscle ultrasound in hereditary muscle disease

In this review we summarise the key techniques of muscle ultrasound as they apply to hereditary muscle disease. We review the diagnostic utility of muscle ultrasound including its role in guiding electromyography and muscle biopsy sampling. We summarize the different patterns of sonographic muscle involvement in the major categories of genetic muscle disorders and discuss the limitations of the technique. We hope to encourage others to adopt ultrasound in their care for patients with hereditary muscle diseases.

Translating Ultrasound into Clinical Practice for the Assessment of Swallowing and Laryngeal Function: A Speech and Language Pathology-Led Consensus Study

Ultrasound (US) has an emerging evidence base for the assessment of swallowing and laryngeal function. Accessibility and technological advances support the use of US as a clinical assessment tool; however, there is insufficient evidence to support its translation into clinical practice. This study aimed to establish consensus on the priorities for translation of US into clinical practice for the assessment of swallowing and laryngeal function. Nominal Group Technique (NGT) was used as a formal method of consensus development. Clinicians and academics, all members of an international US working group, were invited to participate in the study. Two NGT meetings were held, where participants silently generated and then shared ideas. Participants anonymously ranked items. Rankings were aggregated before participants re-ranked items in order of priority. Discussions regarding rankings were recorded and transcribed to inform analysis. Member-checking with participants informed the final analysis. Participants (n = 15) were speech and language pathologists, physiotherapists and sonographers representing six countries. Fifteen items were identified and prioritised 1-13 (including two equally ranked items). Reliability, validity and normative data emerged as key areas for research while development of training protocols and engagement with stakeholders were considered vital to progressing US into practice. Analysis revealed common themes that might be addressed together in research, in addition to the ranked priority. A measured approach to the translation of US into clinical practice will enable effective implementation of this tool. Priorities may evolve as clinical and professional contexts shift, but this study provides a framework to advance research and clinical practice in this field.

Emerging Role of Ultrasound in Dysphagia Assessment and Intervention: A Narrative Review

Ultrasonography has gained increasing attention as a non-invasive and radiation-free instrument for the assessment of swallowing function. In the past decades, an extensive repertoire of ultrasonographic techniques, such as, B-mode dynamic scanning, pixel analysis, M-mode, Doppler, 3D reconstruction, and sonoelastography, has been applied in the evaluation of oropharyngeal structures and movement. Yet, a universal consensus on the examination protocols and clinical implications remains to be established. This review aimed to provide a brief introduction of the application of ultrasound in dysphagia assessment and intervention, encompassing the ultrasonography of swallowing-related muscles, tongue movement, and hyolaryngeal excursion, as well as ultrasound-guided interventions in the management of dysphagia. In addition to non-invasiveness, ultrasonography, a portable, easy to use, and low-cost technique, could compliment videofluoroscopic swallowing study as a first-line screening and follow-up tool for the evaluation of swallowing function, although further study is warranted to provide quantitative diagnostic and prognostic values. Finally, ultrasonography aids in the precisely targeted injection of botulinum toxin in patients exhibiting oropharyngeal muscle spasticity.

Longitudinal Changes of Tongue Thickness and Tongue Pressure in Neuromuscular Disorders

Background

Swallowing dysfunction is related to major cause of adverse events and an indicator of shorter survival among patients with neuromuscular disorders (NMD). It is critical to assess the swallowing function during disease progression, however, there are limited tools that can easily evaluate swallowing function without using videofluoroscopic or videoendoscopic examination. Here, we evaluated the longitudinal changes in tongue thickness (TT) and maximum tongue pressure (MTP) among patients with amyotrophic lateral sclerosis (ALS), myotonic dystrophy type 1 (DM1), and Duchenne muscular dystrophy (DMD).

Methods

Between 2010 and 2020, TT and MTP were measured from 21 ALS, 30 DM1, and 14 DMD patients (mean ages of 66.9, 44.5, and 21.4 years, respectively) at intervals of more than half a year. TT was measured, by ultrasonography, as the distance from the mylohyoid muscle raphe to the tongue dorsum, and MTP was determined by measuring the maximum compression on a small balloon when pressing the tongue against the palate. Then we examined the relationship between these evaluations and patient background and swallowing function.

Results

Mean follow-up periods were 24.0 months in the ALS group, 47.2 months in the DM1group, and 61.1 months in the DMD group. The DMD group demonstrated larger first TT than the other groups, while the DM1 group had lower first MTP than the ALS group. The ALS group showed a greater average monthly reduction in mean TT than the DM1 group and greater monthly reductions in mean body weight (BW) and MTP than the other groups. Significant differences between the first and last BW, TT, and MTP measures were found only in the ALS group.

Conclusions

This study suggests that ALS is associated with more rapid degeneration of tongue function over several years compared to DMD and DM1.

Ultrasound: an emerging modality for the dysphagia assessment toolkit?

PURPOSE OF REVIEW

Videofluoroscopy (VFSS) and fibreoptic endoscopic evaluation of swallowing (FEES) are established instrumental techniques to support differential diagnosis and treatment of oropharyngeal dysphagia. Whilst their value is undisputed, each tool is not without limitations. The COVID-19 pandemic has restricted access to VFSS and FEES leading clinicians to explore alternative or augmentative tools to support swallowing assessment.Ultrasound (US) is an established tool for visualisation of head and neck anatomy, including structures implicated in swallowing. Although US has been utilised in swallowing research for many years, its application has not translated into common clinical practice. This review presents and debates the evidence for and against use of US for clinical swallowing assessment.

RECENT FINDINGS

Evaluation of swallowing muscle morphometry and measurement of isolated swallowing kinematics are two primary uses of US in swallowing assessment that have been identified in the literature. Use of US to detect bolus flow, aspiration and residues is in its early stages and needs further research.

SUMMARY

US shows promise as an adjunctive modality to support assessment of swallowing. With standardisation, these measurements may have potential for transition into clinical care. Reliability and validity testing and development of normative data are imperative to ensure its use as an evidence-based instrumentation.

Diagnostic Value of Muscle Ultrasound for Myopathies and Myositis

Purpose of Review

The purpose of this review is to critically discuss the use of ultrasound in the evaluation of muscle disorders with a particular focus on the emerging use in inflammatory myopathies.

Recent Findings

In myopathies, pathologic muscle shows an increase in echogenicity. Muscle echogenicity can be assessed visually, semi-quantitatively, or quantitatively using grayscale analysis. The involvement of specific muscle groups and the pattern of increase in echogenicity can further point to specific diseases. In pediatric neuromuscular disorders, the value of muscle ultrasound for screening and diagnosis is well-established. It has also been found to be a responsive measure of disease change in muscular dystrophies. In chronic forms of myositis like inclusion body myositis, ultrasound is very suitable for detecting markedly increased echogenicity and atrophy in affected muscles. Acute cases of muscle edema show only a mild increase in echogenicity, which can also reverse with successful treatment.

Summary

Muscle ultrasound is an important imaging modality that is highly adaptable to study various muscle conditions. Although its diagnostic value for neuromuscular disorders is high, the evidence in myositis has only begun to accrue in earnest. Further systematic studies are needed, especially in its role for detecting muscle edema.

Determination of the Relationships Between intra- and Extraoral Tongue Hardness, Thickness, and Pressure Using Ultrasonic Elastography

Involved with various bodily functions, including ingestion and swallowing, the tongue is an important organ. We measured resting tongue hardness using real-time tissue elastography (RTE) to establish a simple tongue evaluation for patients who may have limited capacities to follow commands. Relationships between tongue hardness, thickness, and pressure were investigated, using both intra- and extraoral probes. Assessments were performed for a total of 27 healthy adults (11 male, 16 female, average age 26.4 ± 1.8 years). Measurements of tongue hardness and thickness were made using strain ratios (SR), and averaged across nine images. Maximum tongue pressure was determined using a tongue pressure device. A negative correlation was observed between intraorally measured tongue hardness and maximum tongue pressure (r = -0.76, p < 0.01). A positive correlation between extraorally measured tongue thickness and maximum tongue pressure was observed (r = 0.59, p < 0.01). Additionally, significant differences were observed between males and females with regards to intraorally measured tongue hardness (p = 0.02), maximum tongue pressure (p = 0.02), and extraorally measured tongue thickness (p < 0.01). The results of this study demonstrated the clinical applicability of RTE-based tongue hardness measurements, and suggest the feasibility of predicting tongue strength based on extraoral tongue thickness measurements.

Quantitative ultrasound of the tongue: Echo intensity is a potential biomarker of bulbar dysfunction in amyotrophic lateral sclerosis

OBJECTIVES

To learn if quantitative ultrasound (QUS) distinguishes the tongues of healthy participants and amyotrophic lateral sclerosis (ALS) patients by echo intensity (EI) and to evaluate if EI correlates with measures of bulbar function.

METHODS

Ultrasound was performed along the midline of the anterior tongue surface in 16 ALS patients and 16 age-matched controls using a linear hockey stick 16-7 MHz transducer. A region of interest was manually drawn and then EI was determined for the upper 1/3 of the muscle. For patients, the ALS functional rating scale - revised (ALSFRS-R) was used to calculate bulbar sub-scores and the Iowa Oral Performance Instrument (IOPI) was used to measure tongue strength.

RESULTS

EI was significantly higher in ALS patients than in healthy participants (49.8 versus 37.8 arbitrary units, p < 0.01). In the patient group, EI was negatively correlated with ALSFRS-R bulbar sub-score (R_S = -0.65, p < 0.01). An inverse correlation between EI and tongue strength did not reach significance (R_S = -0.34, p = 0.28).

CONCLUSIONS

This study suggests that EI can differentiate healthy from diseased tongue muscle, and correlates with a standard functional measure in ALS patients.

SIGNIFICANCE

Tongue EI may represent a novel biomarker for bulbar dysfunction in ALS.

Orofacial muscles may be affected in early stages of Becker muscular dystrophy: A preliminary study

BACKGROUND

Dysphagia is reported in patients with Duchenne or Becker muscular dystrophy. Our clinical experience suggests that, compared with Duchenne patients, impaired mastication and swallowing occur early in Becker patients relative to their skeletal muscle involvement. The aim of this study was to assess dysphagia in Duchenne and Becker patients in relation to ambulatory capacity.

METHODS

In patients in the early ambulatory stage, clinical symptoms, quantitative muscle ultrasound of the orofacial muscles, and maximum bite force were assessed. The 6-Minute Walk Test (6MWT) was used to measure ambulatory capacity.

RESULTS

Eleven Duchenne and 11 Becker patients were included. Although Becker patients had a greater 6MWT distance than Duchenne patients, the occurrence of mastication and swallowing difficulties was similar. The temporalis muscle was significantly thicker in Becker patients.

CONCLUSIONS

Clinicians should be aware of dysphagia in both groups, even when ambulation is still well preserved.

Neuromuscular ultrasound in clinical practice: A review

Neuromuscular ultrasound (NMUS) is becoming a standard element in the evaluation of peripheral nerve and muscle disease. When obtained simultaneously to electrodiagnostic studies, it provides dynamic, structural information that can refine a diagnosis or identify a structural etiology. NMUS can improve patient care for those with mononeuropathies, polyneuropathy, motor neuron disease and muscle disorders. In this article, we present a practical guide to the basics of NMUS and its clinical application. Basic ultrasound physics, scanning techniques and clinical applications are reviewed, along with current challenges.

Effect of the head extension swallowing exercise on suprahyoid muscle activity in elderly individuals

Aging causes motor function deterioration in the elderly population, which in turn can cause weakness in the muscles associated with swallowing. Swallowing-related problems in elderly individuals can be prevented or their symptoms can be improved with strengthening exercises for the muscles involved in swallowing. The existing strengthening exercises for the suprahyoid muscle have their limitations. Therefore, it is necessary to find another exercise that can be performed by individuals whose personal characteristics make it difficult for them to perform the existing exercises. In this study, we investigated the changes in suprahyoid muscle activation, tongue strength, and thickness of the suprahyoid muscle after 8 weeks of the head extension swallowing exercise (HESE). A total of 23 healthy elderly individuals participated in an 8-week exercise program (20 min/session, 2 times/week for 8 weeks). Suprahyoid muscle activation during effortful swallowing and the effortful-normal ratio were significantly increased at 8 weeks compared to the baseline values (p = 0.002, and 0.033, respectively). Tongue tip pressure, tongue base pressure, normal swallowing pressure, effortful swallowing pressure, and tongue tip endurance were significantly increased at 8 weeks compared with baseline (p = 0.014, 0.004, 0.046, 0.009, and 0.004, respectively). The thickness of the digastric muscle and that of the mylohyoid muscle were significantly increased at 8 weeks compared with baseline (p = 0.000 and 0.004, respectively). This study showed that HESE can be a good option for improving the suprahyoid muscle and tongue strength in the elderly population. Additionally, this exercise does not require any additional equipment and has the advantage of being able to be performed anytime and anywhere. A variety of exercise options tailored according to individual characteristics may be helpful in choosing the most appropriate exercise.

3D Ultrasound Imaging: Fast and Cost-effective Morphometry of Musculoskeletal Tissue

The developmental goal of 3D ultrasound imaging (3DUS) is to engineer a modality to perform 3D morphological ultrasound analysis of human muscles. 3DUS images are constructed from calibrated freehand 2D B-mode ultrasound images, which are positioned into a voxel array. Ultrasound (US) imaging allows quantification of muscle size, fascicle length, and angle of pennation. These morphological variables are important determinants of muscle force and length range of force exertion. The presented protocol describes an approach to determine volume and fascicle length of m. vastus lateralis and m. gastrocnemius medialis. 3DUS facilitates standardization using 3D anatomical references. This approach provides a fast and cost-effective approach for quantifying 3D morphology in skeletal muscles. In healthcare and sports, information on the morphometry of muscles is very valuable in diagnostics and/or follow-up evaluations after treatment or training.

Can mastication in children with cerebral palsy be analyzed by clinical observation, dynamic ultrasound and 3D kinematics?

The aim of this study was to explore the feasibility of the Mastication Observation and Evaluation (MOE) instrument, dynamic ultrasound and 3D kinematic measurements to describe mastication in children with spastic cerebral palsy and typically developing children. Masticatory movements during five trials of eating a biscuit were assessed in 8 children with cerebral palsy, spastic type (mean age 9.08years) and 14 typically developing children (mean age 9.01years). Differences between trials were tested (t-test) and the mastication of individual children with cerebral palsy was analyzed. MOE scores ranged from 17 to 31 (median 24) for the children with cerebral palsy and from 28 to 32 (median 31) for the typically developing children. There was an increased chewing cycle duration, a smaller left-right and up-down tongue displacement and larger anterior mandible movements for the trials (n=40) of cerebral palsy children (p<0.000 for all comparisons) compared to the trials of typically developing children (n=70). The MOE captures differences in mastication between individual children with cerebral palsy. The MOE items 'jaw movement' and 'fluency and coordination' showed the most similarity with the objective measurements. Objective measurements of dynamic ultrasound and 3D kinematics complemented data from the MOE instrument.

Dystrophic changes in masticatory muscles related chewing problems and malocclusions in Duchenne muscular dystrophy

Dysphagia in Duchenne muscular dystrophy (DMD) worsens with age, with increasingly effortful mastication. The aims of this study were to describe mastication problems in consecutive stages in a group of patients with DMD and to determine related pathophysiological aspects of masticatory muscle structure, tongue thickness, bite force and dental characteristics. Data from 72 patients with DMD (4.3 to 28.0 years), divided into four clinical stages, were collected in a cross sectional study. Problems with mastication and the need for food adaptations, in combination with increased echogenicity of the masseter muscle, were already found in the early stages of the disease. A high percentage of open bites and cross bites were found, especially in the later stages. Tongue hypertrophy also increased over time. Increased dysfunction, reflected by increasingly abnormal echogenicity, of the masseter muscle and reduced occlusal contacts (anterior and posterior open bites) were mainly responsible for the hampered chewing. In all, this study shows the increasing involvement of various elements of the masticatory system in progressive Duchenne muscular dystrophy. To prevent choking and also nutritional deficiency, early detection of chewing problems by asking about feeding and mastication problems, as well as asking about food adaptations made, is essential and can lead to timely intervention.

Muscle ultrasound

Muscle ultrasound is an ideal imaging modality that allows for noninvasive, radiation-free point-of-care neuromuscular imaging. There are many potential applications of muscle ultrasound, including identification of abnormal muscle movements such as fasciculations, evaluation of muscle trauma, identification of physiologic parameters such as pennation angle, accurate performance of chemodenervation, and improved accuracy of challenging electrodiagnostic studies such as phrenic nerve conduction studies or needle electromyogram (EMG) of the diaphragm. Tissue Doppler imaging can be used to help identify inflammatory myopathies. With computer-assisted quantification, muscle ultrasound has high sensitivity and specificity in the diagnosis of pediatric neuromuscular disease and amyotrophic lateral sclerosis, and is a valuable addition to other diagnostic techniques for neuromuscular disease. When used as a first-line screening tool it can obviate the need for more invasive procedures such as EMG or muscle biopsy in certain patients. This chapter provides an overview of the fundamentals, clinical applications, and validation of muscle ultrasound for patients with neuromuscular disorders.

Feeding and Swallowing Disorders in Pediatric Neuromuscular Diseases: An Overview

Feeding and swallowing problems in infants and children have a great impact on health and wellbeing. The aim of this study was to provide an overview of recognized feeding and swallowing problems in different groups of children with neuromuscular diseases, based on relevant literature and expert opinion, and to propose recommendations for the assessment and treatment of these problems. Almost all pediatric neuromuscular diseases are accompanied by feeding and swallowing problems during the different phases of deglutition, problems that give rise to a wide variety of signs and symptoms, which emphasizes the importance of a comprehensive feeding and swallowing assessment by a speech and language therapist.

Transbuccal sonographic evaluation of the local extent of tumors of the tongue with pathological correlation

PURPOSE

The object of this study was to evaluate the usefulness of preoperative transbuccal ultrasound (US) for the evaluation of tongue tumors. Thus, we evaluated the correlation between preoperative US measurements and postoperative pathologic measurements of tongue tumor size.

METHODS

From January 2003 to March 2011, 29 patients with tongue tumors were evaluated. All patients underwent preoperative transbuccal US at 1 day before surgery. Preoperative US was compared with pathology findings, including specimen size. The maximum anterior-posterior (AP) diameter of the long axis of the tumor, the maximum width (WD), and the maximum thickness (TH) of the tumor were measured with US along with a pathologic evaluation of the specimens.

RESULTS

The mean AP was 22 ± 1 mm; WD was 13 ± 6 mm, and TH was 10 ± 5 mm using US. The pathologic mean AP was 21 ± 12 mm; WD was 12 ± 6 mm, and TH was 9 ± 4 mm. The Spearman's correlation coefficients of the AP, WD, and TH were 0.905 (p < 0.001), 0.918 (p < 0.001), and 0.971 (p < 0.001), respectively.

CONCLUSIONS

Transbuccal US is a useful tool for predicting tongue tumor extent.

Reliability of panoramic ultrasound imaging in simultaneously examining muscle size and quality of the hamstring muscles in young, healthy males and females

The purpose of this study was to examine the reliability of ultrasound (US) measures of cross-sectional area (CSA), muscle thickness (MT) and echo intensity (EI) of the hamstrings, with comparisons between males and females. In 20 healthy participants (10 males, 10 females), CSA, MT and EI were measured from panoramic US scans of the hamstrings on 2 separate days. The intra-class correlation coefficients and standard errors of measurement as a percentage of the mean for CSA, MT and EI ranged from 0.715 to 0.984 and from 3.145 to 12.541% in the males and from 0.724 to 0.977 and from 4.571 to 17.890% in the females, respectively. The males had greater CSAs and MTs and lower EIs than the females (p = 0.002-0.049), and significant relationships were observed between CSA and MT (r = 0.714-0.938, p ≤ 0.001-0.023). From an overall reliability standpoint, these findings suggest that panoramic US may be a reliable technique for examining muscle size and quality of the hamstrings in both males and females.

Reduced mandibular range of motion in Duchenne Muscular Dystrophy: predictive factors

Patients with Duchenne muscular dystrophy (DMD) experience negative effects upon feeding and oral health. We aimed to determine whether the mandibular range of motion in DMD is impaired and to explore predictive factors for the active maximum mouth opening (aMMO). 23 patients with DMD (mean age 16.7 ± 7.7 years) and 23 controls were assessed using a questionnaire about mandibular function and impairments. All participants underwent a clinical examination of the masticatory system, including measurement of mandibular range of motion and variables related to mandibular movements. In all patients, quantitative ultrasound of the digastric muscle and the geniohyoid muscle and the motor function measure (MFM) scale were performed. The patients were divided into early and late ambulatory stage (AS), early non-ambulatory stage (ENAS) and late non-ambulatory stage (LNAS). All mandibular movements were reduced in the patient group (P < 0.001) compared to the controls. Reduction in the aMMO (<40 mm) was found in 26% of the total patient group. LNAS patients had significantly smaller mandibular movements compared to AS and ENAS (P < 0.05). Multiple linear regression analysis for aMMO revealed a positive correlation with the body height and disease progression, with MFM total score as the strongest independent risk factor (R(2) = 0.71). Mandibular movements in DMD are significantly reduced and become more hampered with loss of motor function, including the sitting position, arm function, and neck and head control. We suggest that measurement of the aMMO becomes a part of routine care of patients with DMD.

Perioperative respiratory management of pediatric patients with neuromuscular disease

Patients with neuromuscular disorders undergoing general anesthesia present a special set of respiratory problems for perioperative management. While there are disease-specific concerns, there are many common themes in the respiratory management of patients with neuromuscular disorders. These problems are discussed in this review. Such common perioperative concerns include upper airway obstruction, chest wall restriction, postoperative hypoventilation, inadequate airway clearance, and chronic lower airway disease. Each of these challenges has an effective management approach, and careful planning can help avoid perioperative respiratory complications.