Muscle elastography: a new imaging technique for multiple sclerosis spasticity measurement

Stretchable ultrasonic arrays for the three-dimensional mapping of the modulus of deep tissue

Serial assessment of the biomechanical properties of tissues can be used to aid the early detection and management of pathophysiological conditions, to track the evolution of lesions and to evaluate the progress of rehabilitation. However, current methods are invasive, can be used only for short-term measurements, or have insufficient penetration depth or spatial resolution. Here we describe a stretchable ultrasonic array for performing serial non-invasive elastographic measurements of tissues up to 4 cm beneath the skin at a spatial resolution of 0.5 mm. The array conforms to human skin and acoustically couples with it, allowing for accurate elastographic imaging, which we validated via magnetic resonance elastography. We used the device to map three-dimensional distributions of the Young's modulus of tissues ex vivo, to detect microstructural damage in the muscles of volunteers before the onset of soreness and to monitor the dynamic recovery process of muscle injuries during physiotherapies. The technology may facilitate the diagnosis and treatment of diseases affecting tissue biomechanics.

A Bayesian Network Meta-Analysis and Systematic Review of Guidance Techniques in Botulinum Toxin Injections and Their Hierarchy in the Treatment of Limb Spasticity

Accurate targeting of overactive muscles is fundamental for successful botulinum neurotoxin (BoNT) injections in the treatment of spasticity. The necessity of instrumented guidance and the superiority of one or more guidance techniques are ambiguous. Here, we sought to investigate if guided BoNT injections lead to a better clinical outcome in adults with limb spasticity compared to non-guided injections. We also aimed to elucidate the hierarchy of common guidance techniques including electromyography, electrostimulation, manual needle placement and ultrasound. To this end, we conducted a Bayesian network meta-analysis and systematic review with 245 patients using the MetaInsight software, R and the Cochrane Review Manager. Our study provided, for the first time, quantitative evidence supporting the superiority of guided BoNT injections over the non-guided ones. The hierarchy comprised ultrasound on the first level, electrostimulation on the second, electromyography on the third and manual needle placement on the last level. The difference between ultrasound and electrostimulation was minor and, thus, appropriate contextualization is essential for decision making. Taken together, guided BoNT injections based on ultrasound and electrostimulation performed by experienced practitioners lead to a better clinical outcome within the first month post-injection in adults with limb spasticity. In the present study, ultrasound performed slightly better, but large-scale trials should shed more light on which modality is superior.

Spastic muscle stiffness evaluated using ultrasound elastography and evoked electromyogram in patients following severe traumatic brain injury: an observational study

OBJECTIVE

To determine the relationship between muscle stiffness assessed using ultrasound shear wave elastography, spinal motor neuron excitability assessed using the F wave, and clinical findings of spasticity in patients with spastic muscle overactivity following severe traumatic brain injury.

METHODS

This study enrolled 17 inpatients with severe traumatic brain injury and 20 healthy volunteers. Biceps brachii muscle stiffness was then evaluated using ultrasound shear wave speed. Spinal motor neuron excitability was evaluated using the F/M ratio recorded from abductor pollicis brevis muscle. Clinical parameters, such as the modified Ashworth scale and modified Tardieu scale, were assessed in the patient with traumatic brain injury.

RESULTS

The patients with traumatic brain injury group had a significantly higher shear wave speed and F/M ratio compared with the healthy group. A higher shear wave speed was correlated with higher clinical spastic severity in patients with traumatic brain injury. The F/M ratio was not significantly correlated with clinical spastic severity.

CONCLUSION

Ultrasound shear wave elastography might be helpful for assessing muscle stiffness in patients with spastic muscle overactivity following severe traumatic brain injury. Further studies comprising larger cohorts are warranted.

[Clinical practice guideline for the treatment of spasticity: Consensus and algorithms]

Spasticity is a complex phenomenon of extremely variable clinical expression, a dynamic and evolutionary process that can condition the activity and treatment of the patient. The current recommendation for early treatment aims to avoid progression and complications, and involves an individualized approach based on a wide range of pharmacological and non-pharmacological measures. This guide results from a forum of expert specialists who faced some frequent uncertainties in the assessment process and therapeutic approach of the spastic patient such as the suitability of initiating treatment, considerations for initiating, continuing and ceasing treatment with botulinum toxin, adjuvant treatments, pain or follow-up. The result is one algorithm of decision for the therapeutic approach of spasticity. Both scientific progress and the exchange of clinical experience on which this guide is based, can support decision-making on some areas of gloom that we find in daily practice.

Evidence-based management of multiple sclerosis spasticity with nabiximols oromucosal spray in clinical practice: a 10-year recap

Effective symptomatic management of multiple sclerosis (MS) spasticity remains an unmet need for many patients. The second-line option nabiximols is the most widely investigated of the noninvasive antispasticity medications in this patient population. Clinical evidence accumulated with nabiximols since it was first approved in Europe in 2010 suggests that about 40% of initial responders (i.e., those with ≥20% improvement in their baseline 0-10 Numerical Rating Scale score) may expect to achieve clinically meaningful (≥30% Numerical Rating Scale response) and durable symptomatic improvement in MS spasticity. During 10 years' routine use of nabiximols, no new safety signals have emerged. Nabiximols-associated improvement in MS spasticity-related symptoms such as pain and sleep disruption suggests a need to track possible therapeutic effects beyond muscle tone control.

Ultrasound elastography

Physicians have used palpation as a diagnostic examination to understand the elastic properties of pathology for a long time since they realized that tissue stiffness is closely related to its biological characteristics. US elastography provided new diagnostic information about elasticity comparing with the morphological feathers of traditional US, and thus expanded the scope of the application in clinic. US elastography is now widely used in the field of diagnosis and differential diagnosis of abnormality, evaluating the degree of fibrosis and assessment of treatment response for a range of diseases. The World Federation of Ultrasound Medicine and Biology divided elastographic techniques into strain elastography (SE), transient elastography and acoustic radiation force impulse (ARFI). The ARFI techniques can be further classified into point shear wave elastography (SWE), 2D SWE, and 3D SWE techniques. The SE measures the strain, while the shear wave-based techniques (including TE and ARFI techniques) measure the speed of shear waves in tissues. In this review, we discuss the various techniques separately based on their basic principles, clinical applications in various organs, and advantages and limitations and which might be most appropriate given that the majority of doctors have access to only one kind of machine.

Safety and tolerability of nabiximols oromucosal spray: a review of more than 15 years" accumulated evidence from clinical trials

Introduction: Nabiximols, a cannabinoid-based oromucosal spray, is indicated as add-on therapy for symptomatic relief of spasticity in persons with multiple sclerosis (MS). This review compiles tolerability and safety data from clinical trials that investigated nabiximols for spasticity and/or chronic pain.Areas covered: Systematic searches identified 38 placebo-controlled randomized controlled trials (RCTs) or post-RCT open-label studies reporting safety data: 15 in spasticity; 16 in neuropathic pain; six in chronic cancer pain; and one in rheumatoid arthritis pain. In RCTs, discontinuation rates due to adverse events (AEs) for nabiximols and placebo were lower in spasticity studies (5.4% and 2.8%) than in neuropathic pain (12.9% and 5.3%) or cancer pain (19.5% and 16.6%) studies. The most consistently identified AEs were dizziness, nausea and fatigue in spasticity or neuropathic pain studies; and dizziness, nausea, vomiting and somnolence in cancer pain studies. Serious AE (SAE) rates for nabiximols and placebo were higher in cancer pain (21.8% and 16.9%) than in MS spasticity (4.7% vs. 0.8%) and neuropathic pain (4.1% vs. 3.1%) studies despite similar dose ranges. Treatment-related SAEs showed no particular pattern.Expert opinion: More than 15 years of investigation of nabiximols oromucosal spray in spasticity and chronic pain conditions indicates an acceptable overall safety profile.

Ultrasound Elastography in the Assessment of the Stiffness of Spastic Muscles: A Systematic Review

The incidence of muscle spasticity is high in patients with diseases of the central nervous system. This condition leads to significant limitations in movement and impaired functional capacities. Muscle spasticity manifests as changes in the mechanical properties of the muscles. This muscle disorder is generally assessed using qualitative methods, whose validity, reliability and sensitivity are questionable. In recent years, ultrasound elastography (USE) has been used as a non-invasive technique for characterizing the stress response and mechanical properties of individual muscles in the evaluation of spasticity. This article presents a systematic review of the USE techniques, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) declaration guidelines, used for the evaluation of muscle stiffness caused by spasticity. The articles selected in this study were evaluated using the Quality Appraisal of Diagnostic Reliability (QAREL) tool. Mainly, studies on the assessment of spasticity involving the evaluation of muscle stiffness with USE techniques (i.e., shear-wave elastography [SWE] or compression elastography [CE]) were selected. Then, common topics related to the assessment of spastic muscles and the statistical results of these studies were classified. Of 21 articles, nine used only CE, 10 used only SWE and two used both techniques. In the studies, statistically significant differences were observed in the measurements of muscle stiffness between the paretic and non-paretic sides as well as between patients and healthy patients. The clinical measurements obtained, devices used and assessment and probe positions for both techniques were discussed. The most frequently studied muscles were the biceps (n = 7) and gastrocnemius (n = 11). On applying the QAREL tool, we found that only two studies showed compliance at 80%-90%, seven studies at 50%-70% and the remaining 12 at 10%-40%. The results showed that USE techniques have limitations in spasticity assessment, such as subjectivity because of the lack of standardized protocols. A deficit of studies on intra-operator and inter-operator measurements indicates that this technique is not yet mature for spasticity diagnosis, although it is a promising diagnostic tool for designing treatment plans and monitoring the effectiveness of therapeutic modalities.

Safety and tolerability of nabiximols oromucosal spray: a review of real-world experience in observational studies, registries, and case reports

INTRODUCTION

: Nabiximols oromucosal spray,a cannabis-based medicine containing a balanced ratio of Δ-9-tetrahydrocannabinol and cannabidiol, is approved widely as an add-on therapy for symptomatic relief of spasticity in people with multiple sclerosis (MS). Most safety data for nabiximols derive from use in MS spasticity, with some data available from the analgesia area.

AREAS COVERED

: This review compiles safety and tolerability data from all published observational studies, registry analyses, and case reports identified in systematic searches in which nabiximols oromucosal spray was investigated for spasticity (n = 20) and/or chronic non-cancer pain (n = 4). Aligning with the known safety profile of nabiximols as demonstrated in randomized controlled trials, common adverse events reported consistently across studies conducted under clinical practice conditions were dizziness, fatigue and somnolence. The serious adverse event (SAE) rate with nabiximols in MS spasticityobservational studies was 3.1% (137/4351). A total of 39 treatment-related SAEs were reported in 32 patients with spasticity, all of which (where specified) were resolved. No treatment-related SAEs were recorded in nabiximols pain studies.

EXPERT OPINION

: Real-world experience with nabiximols oromucosal spray in treating spasticity and chronic pain indicates that, overall, it is well tolerated and has a good safety profile.

Short and long term effects of Nabiximols on balance and walking assessed by 3D-gait analysis in people with Multiple Sclerosis and spasticity

BACKGROUND

Spasticity in people with Multiple Sclerosis (pwMS) is one of the most disabling symptoms on walking ability and balance. Among the systemic antispastic drugs, Nabiximols showed a good tolerability, safety profile and relevant efficacy. A few studies assessed long-term effects of this drug through clinical scales and instrumental tools, but no study investigated short-term effects. The aim of our study is to quantitatively evaluate the immediate effects of Nabiximols on walking and balance and their maintenance after 4 weeks in pwMS and spasticity.

METHODS

pwMS were enrolled and randomized in 2 treatment groups: Sativex (SG) and control (CG) group. All patients were assessed at T0 (before the first Sativex puff), T1(after 45 minutes) and T2 (after 4 weeks of treatment) using clinical scales and 3d-Gait Analysis . Then, the patients treated with Sativex, were divided into 5 subgroups according to Numeric Rating Scale for spasticity (NRSs) and Berg Balance Score (BBS) response: NRSs responder[1] and non-[2]; BBS responders[3] and non-[4]; NRSs-BBS responders[5].

RESULTS

32 pwMS (22 SG, 10 CG) were recruited. Significant improvements were found between T0 and T1 in SG compared to CG in a few clinical and kinematic parameters. Larger significant differences were found for NRSs and BBS responders' groups versus CG. Eventually, no significant differences were found comparing the results between T1 and T2, suggesting the persistence of the improvements emerged at T1.

CONCLUSION

These results quantitatively demonstrated a short time effect of Nabiximols on balance and walking of pwMS, which is mantained after 4 weeks. Patients identified as responder by combination of NRSs and BBS showed the best efficacy. These findings may suggest how to early select the real responders in order to improve the adherence and cost-effectiveness of the therapy.

Skeletal muscle stiffness as measured by magnetic resonance elastography after chronic spinal cord injury: a cross-sectional pilot study

Skeletal muscle stiffness is altered after spinal cord injury (SCI). Assessing muscle stiffness is essential for rehabilitation and pharmaceutical interventions design after SCI. The study used magnetic resonance elastography to assess the changes in stiffness after chronic SCI compared to matched able-bodied controls and determine its association with muscle size, spasticity, and peak torque in persons with SCI. Previous studies examined the association between muscle stiffness and spasticity, however, we are unaware of other studies that examined the effects of muscle composition on stiffness after SCI. Ten participants (one female) with chronic SCI and eight (one female) matched able-bodied controls participated in this cross-sectional study. Magnetic resonance elastography was utilized to monitor stiffness derived from shear waves propagation. Modified Ashworth scale was used to evaluate spasticity scores in a blinded fashion. Peak isometric and isokinetic torques were measured using a biodex dynamometer. Stiffness values were non-significantly lower (12.5%; P = 0.3) in the SCI group compared to able-bodied controls. Moreover, stiffness was positively related to vastus lateralis whole muscle cross-sectional area (CSA) (r² = 0.64, P < 0.005) and vastus lateralis absolute muscle CSA after accounting for intramuscular fat (r² = 0.78, P < 0.0007). Stiffness was also positively correlated to both isometric (r²= 0.55-0.57, P < 0.05) and isokinetic peak (r²= 0.46-0.48, P < 0.05) torques. Our results suggest that larger clinical trial is warranted to confirm the preliminary findings that muscle stiffness is altered after SCI compared to healthy controls. Stiffness appeared to be influenced by infiltration of intramuscular fat and modestly by the spasticity of the paralyzed muscles. The preliminary data indicated that the relationship between muscle stiffness and peak torque is not altered with changing the frequency of pulses or angular velocities. All study procedures were approved by the Institutional Review Board at the Hunter Holmes McGuire VA Medical Center, USA (IRB #: 02314) on May 3, 2017.

Quantitative Ultrasound Imaging to Assess Skeletal Muscles in Adults with Multiple Sclerosis: A Feasibility Study

OBJECTIVES

The aim of this study was to assess the feasibility of quantitative ultrasound imaging (QUI) in assessing the biceps brachii muscle and gastrocnemius muscle in adults with multiple sclerosis (MS).

METHODS

From May to October 2018, we prospectively performed B-mode ultrasound imaging and ultrasound strain elastography of the biceps brachii muscle and gastrocnemius muscle in 24 patients with MS and 10 age-matched healthy volunteers. ImageJ (https://imagej.nih.gov/ij) was used to assess the muscle pixel intensity in grayscale images. Using 2-dimensional speckle-tracking software, we estimated the muscle axial peak strain (maximum deformation) produced by manual compression with an ultrasound transducer and the muscle longitudinal peak strain (maximum displacement) produced by passive elbow and ankle movements. Muscle QUI parameters used in the study included the mean pixel intensity, axial peak strain ratio (SR = muscle strain/subcutaneous tissue strain), and longitudinal peak SR. Statistical analyses included 1-way analysis of variance and a post hoc test to examine the differences in QUI parameters among 3 groups (1, affected muscle in patients with MS; 2, unaffected muscle in patients with MS; and 3, healthy muscle in controls) and, in all paired groups, an unpaired t test to compare the muscle SR in patients with MS with a Modified Ashworth Scale (MAS) score of 1 or higher to those with an MAS score of 0.

RESULTS

The mean age of the 24 patients with MS was 43 years, and all patients and volunteers were female. We observed a significant difference in QUI parameters among the affected muscle in MS, unaffected muscle in MS, and healthy muscle in all paired groups and in patients with MS between an MAS score of 1 or higher and an MAS score of 0 (all P < .05). Interobserver and intraobserver variability in performing QUI was good (intraclass correlation coefficients >0.75).

CONCLUSIONS

Our results suggest that QUI is feasible to assess muscle echogenicity and mechanical behaviors in adult MS.

Assessment and Measurement of Spasticity in MS: State of the Evidence

PURPOSE OF REVIEW

The purpose of this review is to familiarize the reader with assessments and measurement of spasticity in people with multiple sclerosis (MS). Spasticity affects 60-84% of people with MS, worsening as disability worsens and impacting activity, participation, and quality of life. Spasticity manifests in many ways, including spasms, resistance to passive stretch, pain, and perception of tightness, and can affect muscles throughout the body, making assessment and quantification of spasticity challenging but important. Assessment tools include those quantified by clinicians, instrumentation, and patients.

RECENT FINDINGS

Most tools for measuring spasticity are based on clinician scoring, were developed many years ago, and have undergone minimal recent advances. More recent developments are patient-reported outcome measures for spasticity, including the Numeric Rating Scale for Spasticity (NRS-S) and the disease-specific Multiple Sclerosis Spasticity Scale-88 (MSSS), and, most recently, imaging through elastography. MS-related spasticity is common and often disabling. There are various spasticity measurement tools available, each with advantages and limitations. Newer tools are likely to be developed as our understanding of spasticity in MS grows.

Alterations of Elastic Property of Spastic Muscle With Its Joint Resistance Evaluated From Shear Wave Elastography and Biomechanical Model

This study aims to quantify passive muscle stiffness of spastic wrist flexors in stroke survivors using shear wave elastography (SWE) and to correlate with neural and non-neural contributors estimated from a biomechanical model to hyper-resistance measured during passive wrist extension. Fifteen hemiplegic individuals after stroke with Modified Ashworth Scale (MAS) score larger than one were recruited. SWE were used to measure Young's modulus of flexor carpi radialis muscle with joint from 0° (at rest) to 50° flexion (passive stretch condition), with 10° interval. The neural (NC) and non-neural components i.e., elasticity component (EC) and viscosity component (VC) of the wrist joint were analyzed from a motorized mechanical device NeuroFlexor® (NF). Combining with a validated biomechanical model, the neural reflex and muscle stiffness contribution to the increased resistance can be estimated. MAS and Fugl-Meyer upper limb score were also measured to evaluate the spasticity and motor function of paretic upper limb. Young's modulus was significantly higher in the paretic side of flexor carpi radialis than that of the non-paretic side (p < 0.001) and it increased significantly from 0° to 50° of the paretic side (p < 0.001). NC, EC, and VC on the paretic side were higher than the non-paretic side (p < 0.05). There was moderate significant positive correlation between the Young's Modulus and EC (r = 0.565, p = 0.028) and VC (r = 0.645, p = 0.009) of the paretic forearm flexor muscle. Fugl-Meyer of the paretic forearm flexor has a moderate significant negative correlation with NC (r = -0.578, p = 0.024). No significant correlation between MAS and shear elastic modulus or NF components was observed. This study demonstrated the feasibility of combining SWE and NF as a non-invasive approach to assess spasticity of paretic muscle and joint in stroke clinics. The neural and non-neural components analysis as well as correlation findings of muscle stiffness of SWE might provide understanding of mechanism behind the neuromuscular alterations in stroke survivors and facilitate the design of suitable intervention for them.

Newest evidence for tetrahydrocannabinol:cannabidiol oromucosal spray from postapproval pragmatic studies

Postapproval studies have an essential role in demonstrating that an intervention is effective and well tolerated during use in daily clinical practice. Numerous large observational and registry studies of tetrahydrocannabinol (THC):cannabidiol (CBD) oromucosal spray have been conducted subsequent to its approval in Europe in 2011. Collectively, these studies provide valuable insight into various aspects of THC:CBD spray during real-world use in patients with multiple sclerosis spasticity, including its long-term effectiveness and tolerability. The Italian Medicines Agency's web-based registry is the largest observational study of THC:CBD oromucosal spray conducted to date, reporting on more than 1600 patients prescribed THC:CBD spray since it was introduced in Italy in 2013, and further supporting its effectiveness and tolerability profile.

Multiple sclerosis symptoms and spasticity management: new data

Spasticity, perceived by patients as muscle rigidity and spasms, is a common symptom in multiple sclerosis (MS). It is associated with functional impairment that can exacerbate other MS symptoms and reduce quality of life. Pharmacological treatment options are limited and frequently ineffective. Treatment adherence is a key issue to address in these patients. The efficacy and safety of 9-delta-tetrahydrocannabinol:cannabidiol (THC:CBD) oromucosal spray for treatment of MS spasticity were demonstrated in four Phase III trials. Observational studies and registry data subsequently confirmed the effectiveness and tolerability of THC:CBD oromucosal spray under everyday practice conditions. Among patients who respond to treatment, THC:CBD oromucosal spray has been shown to produce positive improvements in gait parameters and to normalize muscle fibers.

Special Considerations and Assessment in Patients with Multiple Sclerosis

Multiple sclerosis is a progressive autoimmune neurologic disorder that may affect any region of the central nervous system. Spasticity in patients with multiple sclerosis can be debilitating and detrimental to the function and quality of life of patients. Treatment options include oral medications, chemodenervation, physical therapy, and modalities. Cannabinoids in the form of a delta-9-tetrahydrocannabinol/cannabidiol oro-mucosal spray has been shown to be effective in addressing spasticity in multiple sclerosis. Successful treatment of spasticity will be integrated, multimodal, and individualized.

Spasticity Measurement

Spasticity is a serious problem that adversely affects the daily life of patients, and creates difficulties for caregivers. The symptom that causes the most disability in multiple sclerosis patients is spasticity. The methods used in the measurement and evaluation of spasticity have some incomplete aspects and errors. In this article, we examined and compared the old and new methods used in the quantitative evaluation of spasticity, and tried to define the ideal method.

What's new in multiple sclerosis spasticity research? Poster session highlights

Each year at the Multiple Sclerosis Experts Summit, relevant research in the field of multiple sclerosis spasticity is featured in poster sessions. The main studies presented at this year's meeting are summarized herein.

Delta-9-Tetrahydrocannabinol/Cannabidiol Oromucosal Spray (Sativex®): A Review in Multiple Sclerosis-Related Spasticity

Delta-9-tetrahydrocannabinol (THC)/cannabidiol (CBD) oromucosal spray (THC/CBD, Sativex^®, nabiximols) is available in numerous countries worldwide for the treatment of multiple sclerosis (MS)-related moderate to severe spasticity in patients who have not responded adequately to other anti-spasticity medication and who demonstrate clinically significant improvement in spasticity-related symptoms during an initial trial of therapy. Twelve weeks' therapy with THC/CBD improved MS-related spasticity in patients with an inadequate response to other anti-spasticity agents who had undergone a successful initial trial of THC/CBD therapy, according to the results of a pivotal phase 3 trial. Improvements in spasticity were maintained in the longer term with THC/CBD with no evidence of dose tolerance, and results of real-world studies confirm the effectiveness of THC/CBD in everyday clinical practice. Improvements in health-related quality of life and activities of daily living were also seen with THC/CBD. THC/CBD is generally well tolerated; adverse effects such as dizziness may occur whilst the THC/CBD dosage is being optimized. THC/CBD has low abuse potential and a low risk of psychoactive effects. In conclusion, THC/CBD oromucosal spray is a useful option for the treatment of MS-related spasticity not completely relieved with current anti-spasticity medication.