Shear-wave elastography in the diagnosis of ulnar tunnel syndrome

Diagnostic efficiency of conventional ultrasound, shear wave elastography, and superb microvascular imaging in evaluating ulnar neuropathy at the elbow

INTRODUCTION/AIMS

The current diagnosis of ulnar neuropathy at the elbow (UNE) relies mainly on the clinical presentation and nerve electrodiagnostic (EDX) testing, which can be uncomfortable and yield false negatives. The aim of this study was to investigate the diagnostic value of conventional ultrasound, shear wave elastography (SWE), and superb microvascular imaging (SMI) in diagnosing UNE.

METHODS

We enrolled 40 patients (48 elbows) with UNE and 48 healthy volunteers (48 elbows). The patients were categorized as having mild, moderate or severe UNE based on the findings of EDX testing. The cross-sectional area (CSA) was measured using conventional ultrasound. Ulnar nerve (UN) shear wave velocity (SWV) and SMI were performed in a longitudinal plane.

RESULTS

Based on the EDX findings, UNE severity was graded as mild in 4, moderate in 10, and severe in 34. The patient group showed increased ulnar nerve CSA and stiffness at the site of maximal enlargement (CSA mean at the site of max enlargement [CSAmax] and SWV mean at the site of max enlargement [SWVmax]), ulnar nerve CSA ratio, and stiffness ratio (elbow-to-upper arm), compared with the control group (p < .001). Furthermore, the severe UNE group showed higher ulnar nerve CSAmax and SWVmax compared with the mild and moderate UNE groups (p < .001). The cutoff values for diagnosis of UNE were 9.5 mm2 for CSAmax, 3.06 m/s for SWVmax, 2.00 for CSA ratio, 1.36 for stiffness ratio, and grade 1 for SMI.

DISCUSSION

Our findings suggest that SWE and SMI are valuable diagnostic tools for the diagnosis and assessment of severity of UNE.

Elastography of nerves in the wrists of cyclists

Purpose

This study aimed to investigate changes in the elasticity of the median and ulnar nerves in cyclists.

Material and methods

The study included 30 cyclists and 2 non-biking reference groups that included 32 healthy volunteers and 32 individuals with ulnar nerve entrapment neuropathies. All participants underwent physical, ultrasonographic, and elastographic examinations including assessment of nerve cross-sectional area (CSA) and stiffness (SWE). The cyclists' group was tested before and after a 2-hour workout.

Results

The values of ulnar nerve CSA and stiffness in Guyon's canal in resting cyclists were 5.30 ± 1.51 mm2 and 49.05 ± 11.18 kPa, respectively. These values were significantly higher than in the healthy volunteers, but not higher than in the nerve entrapment group. Median nerve CSA and stiffness at rest were 9.10 ± 2.61 mm2 and 38.54 ± 14.87 kPa, respectively. Both values were higher than respective values in the healthy group. Cycling induced an increase in all these parameters, although the increase in nerve stiffness was more noticeable than in CSA.

Conclusions

The elasticity of the median and ulnar nerve in cyclists remains within normal limits, questioning the belief that cyclists are at risk of nerve palsy in Guyon's canal. However, cycling workout does exert compression, resulting in transient oedema of both nerves. The dynamics of changes was more noticeable in SWE examination than in conventional ultrasound, which may depend on SWE sensitivity.

Applications of ultrasound elastography to hand and upper limb disorders

Ultrasound elastography is a recently developed method for accurate measurement of soft tissue stiffness in addition to the clinician's subjective evaluation. The present review briefly describes the ultrasound elastography techniques and outlines clinical applications for tendon, muscle, nerve, skin and other soft tissues of the hand and upper limb. Strain elastography provides a qualitative evaluation of the stiffness, and shear-wave elastography generates quantitative elastograms superimposed on a B-mode image. The stiffness in degenerative tendinopathy and/or tendon injury was significantly lower than in a normal tendon in several studies. Elastography is also a reliable method to evaluate functional muscle activity, compared to conventional surface electromyography. The median nerve is consistently stiffer in patients with carpal tunnel syndrome than in healthy subjects, on whatever ultrasound elastography technique. Elastography distinguishes normal skin from scars and can be used to evaluate scar severity and treatment. Elastography has huge clinical applications in musculoskeletal tissues. Continued development of systems and increased training of clinicians will expand our knowledge of elastography and its clinical applications in the future.

The elastography of distal ulnar nerve branches in cyclists

INTRODUCTION

Forced elbow flexion and pressure during bicycling result in ulnar nerve traction and pressure exerted in Guyon's canal or the nerve's distal branches. The compression of the nerves causes a change in their stiffness related to edema and eventually gradual fibrosis.

PURPOSE

This study aimed to evaluate the elastography of terminal branches of the ulnar nerve in cyclists.

STUDY DESIGN

Cross-sectional study.

METHODS

Thirty cyclists, 32 healthy individuals, and 32 volunteers with ulnar nerve entrapment neuropathies participated in the study. Each participant underwent a nerve examination of the cubital tunnel, Guyon's canal and the deep and superficial branches of the ulnar nerve using shear wave elastography. The cyclist group was tested before and after a 2-hour-long workout.

RESULTS

Before cycling workouts, the ulnar nerve stiffness in the cubital tunnel and Guyon's canal remained below pathological estimates. Cycling workouts altered nerve stiffness in the cubital tunnel only. Notably, the stiffness of the ulnar terminal branches in cyclists was increased even before training. The mean deep branch stiffness was 50.85 ± 7.60 kPa versus 20.43 ± 5.95 kPa (p < 0.001) in the cyclist and healthy groups, respectively, and the mean superficial branch stiffness was 44 ± 12.45 kPa versus 24.55 ± 8.05 kPa (p < 0.001), respectively. Cycling contributed to a further shift in all observed values.

DISCUSSION

These observations indicate the existence of persistent anatomical changes in the distal ulnar branches in resting cyclists that result in increased stiffness of these nerves. The severity of these changes remains, however, to be determined.

CONCLUSIONS

These data show elastography values of the ulnar terminal branches in healthy individuals and cyclists where despite lack of clinical symptoms that they seem to be elevated twice above the healthy range.

Ultrasound Imaging and Guidance for Distal Peripheral Nerve Pathologies at the Wrist/Hand

Ultrasound has emerged as a highly valuable tool in imaging peripheral nerve lesions in the wrist region, particularly for common pathologies such as carpal tunnel and Guyon's canal syndromes. Extensive research has demonstrated nerve swelling proximal to the entrapment site, an unclear border, and flattening as features of nerve entrapments. However, there is a dearth of information regarding small or terminal nerves in the wrist and hand. This article aims to bridge this knowledge gap by providing a comprehensive overview concerning scanning techniques, pathology, and guided-injection methods for those nerve entrapments. The median nerve (main trunk, palmar cutaneous branch, and recurrent motor branch), ulnar nerve (main trunk, superficial branch, deep branch, palmar ulnar cutaneous branch, and dorsal ulnar cutaneous branch), superficial radial nerve, posterior interosseous nerve, palmar common/proper digital nerves, and dorsal common/proper digital nerves are elaborated in this review. A series of ultrasound images are used to illustrate these techniques in detail. Finally, sonographic findings complement electrodiagnostic studies, providing better insight into understanding the whole clinical scenario, while ultrasound-guided interventions are safe and effective for treating relevant nerve pathologies.

ACR Appropriateness Criteria® Chronic Elbow Pain

Chronic elbow pain can be osseous, soft tissue, cartilaginous, and nerve related in etiology. Imaging plays an important role in differentiating between these causes of chronic elbow pain. This document provides recommendations for imaging of chronic elbow pain in adult patients. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Cervical muscle stiffness and parasympathetic nervous system improvements for treatment-resistant depression

BACKGROUND

Although treatment-resistant depression (TRD) is a major public health problem that increases mortality due to suicides, a considerable percentage of patients do not respond adequately to variable treatments. Patients with TRD sometimes have comorbid cervical stiffness. This observational study aims to examine the association of local modulation of cervical muscles with TRD and to learn the involvement of the parasympathetic nervous system in the underlying mechanism.

METHODS

A total of 1103 hospitalized patients with TRD who were resistant to outpatient care were enrolled between May 2006 and October 2021. All patients underwent local modulation of the cervical muscles by physical therapy during hospitalization. The presence or absence of TRD and whole-body disorders, such as headache, dazzling, cervical stiffness, and cardiovascular and gastrointestinal disorders, was determined by the patient's subjectivity using the self-rated medical interview sheet at admission and discharge. Pupil light reflex parameters were also measured at admission and discharge using a binocular infrared pupilometer.

RESULTS

The improvement rate of TRD during hospitalization was 72.1%, and did not differ significantly by sex, age, and hospitalization period. The improvement of TRD showed a strong association with those of cervical stiffness and dazzling, a pupil light reflex disorder (p < 0.001: odds ratios = 12.76 and 6.39, respectively), but not with those of headache or cardiovascular and gastrointestinal disorders (p > 0.05). In the TRD-improved patients, the pupil light reflex parameters representative of the parasympathetic nervous system function ameliorated: pupil diameter decreased, while constriction rate and velocity increased during hospitalization. In contrast, little amelioration of the parameters was seen in the TRD-unimproved patients.

CONCLUSIONS

Cervical muscle stiffness may be associated with TRD, possibly through dysfunction of the parasympathetic nervous system.

TRIAL REGISTRATION

ID: UMIN000040590. First registration date: 30/05/2020.

Extremity compartment syndrome: A review with a focus on non-invasive methods of diagnosis

The article deals with an overview of acute extremity compartment syndrome with a focus on the option of non-invasive detection of the syndrome. Acute extremity compartment syndrome (ECS) is an urgent complication that occurs most often in fractures or high-energy injuries. There is still no reliable method for detecting ECS. The only objective measurement method used in clinical practice is an invasive measurement of intramuscular pressure (IMP). The purpose of this paper is to summarize the current state of research into non-invasive measurement methods that could allow simple and reliable continuous monitoring of patients at risk of developing ECS. Clinical trials are currently underway to verify the suitability of the most studied method, near-infrared spectroscopy (NIRS), which is a method for measuring the local oxygenation of muscle compartments. Less explored methods include the use of ultrasound, ultrasound elastography, bioimpedance measurements, and quantitative tissue hardness measurements. Finding a suitable method for continuous non-invasive monitoring of the syndrome would greatly improve the quality of care for patients at risk. ECS must be diagnosed quickly and accurately to prevent irreversible tissue damage that can occur within hours of syndrome onset and may even warrant amputation if neglected.

Application of shear wave elastography and median nerve cross-section area in the diagnosis and staging of carpal tunnel syndrome: a case-control study

Purpose

Imaging is gaining a more prominent role in the diagnosis of carpal tunnel syndrome (CTS), especially ultrasonography. Shear wave elastography (SWE) is a novel qualitative method to study mechanical changes in tissue. In this study, we aim to assess the role of SWE in diagnosing and staining of the disease.

Material and methods

A total of 124 wrists were included in the study. Seventy wrists had CTS, and 54 were included as the control group. All of the wrists with CTS had staging done with nerve conduction study. All patients underwent ultrasonography by an expert radiologist and had the SWE and cross-section of the median nerve determined. These values were compared among the 2 groups and different stages of CTS. The receiver operating characteristic curve was utilized to assess the diagnostic role of each of the variables.

Results

Cross-section area (CSA) and SWE were significantly different between the 2 groups (p = 0.0001). CSA was also significantly different among various stages of CTS. SWE was not significantly different among moderate and severe stages of CTS. Both of the variables had a good ability to distinguish mild CTS from healthy wrists (p = 0.0001).

Conclusion

SWE can be used in diagnosing CTS and in the staging of the disease.

Post-Operative Assessment of Ulnar Nerve Tension Using Shear-Wave Elastography

BACKGROUND

Ulnar nerve compression at the elbow level is the second-most common entrapment neuropathy. The aim of this study was to use shear-wave elastography for the quantification of ulnar nerve elasticity in patients after ulnar nerve decompression with anterior transposition and in the contralateral non-operative side.

METHOD

Eleven patients with confirmed diagnosis and ulnar nerve decompression with anterior transposition were included and examinations were performed on an Aixplorer^TM ultrasound system (Supersonic Imagine, Aix-en-Provence, France).

RESULTS

We observed significant differences at 0-degree (p < 0.001), 45-degree (p < 0.05), 90-degree (p < 0.01) and 120-degree (p < 0.001) elbow flexion in the shear elastic modulus of the ulnar nerve in the operative and non-operative sides. There were no statistically significant differences between the elasticity values of the ulnar nerve after transposition at 0-degree elbow flexion and in the non-operative side at 120-degree elbow flexion (p = 0.39), or in the ulnar nerve after transposition at 120-degree elbow flexion and in the non-operative side at 0-degree elbow flexion (p = 0.09).

CONCLUSION

Shear-wave elastography has the potential to be used postoperatively as a method for assessing nerve tension noninvasively by the estimation of mechanical properties, such as the shear elastic modulus.

Review Article "Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date"

Neuromuscular ultrasound is rapidly becoming incorporated into clinical practice as a standard tool in the assessment of peripheral nerve diseases. Ultrasound complements clinical phenotyping and electrodiagnostic evaluation, providing critical structural anatomical information to enhance diagnosis and identify structural pathology. This review article examines the evidence supporting neuromuscular ultrasound in the diagnosis of compressive mononeuropathies, traumatic nerve injury, generalised peripheral neuropathy and motor neuron disease. Extending the sonographic evaluation of nerves beyond simple morphological measurements has the potential to improve diagnostics in peripheral neuropathy, as well as advancing the understanding of pathological mechanisms, which in turn will promote precise therapies and improve therapeutic outcomes.

Shear wave elastography of the radial nerve in healthy subjects

Objective

This study was performed to examine the sonoelastographic features of the radial nerve in healthy subjects.

Methods

In this observational cross-sectional study, shear wave elastography was used to evaluate the radial nerve. The cross-sectional area and stiffness were measured.

Results

The study included 37 nerves in 20 healthy adult subjects. The mean cross-sectional area of the radial nerve at the arm was 6.1 mm². The mean stiffness of the radial nerve in the short axis was 30.3 kPa, and that in the long axis was 34.9 kPa. The elasticity measurements were significantly different between the long axis and short axis.

Conclusion

The elastic modulus of the radial nerve was studied in healthy subjects and can serve as a reference for future assessment of different radial nerve pathologies.

Role of shear wave elastography in treatment follow-up of leprosy neuropathy

PURPOSE

Grayscale ultrasonography when complemented with shear wave elastography helps in better evaluation of treatment response of leprosy neuropathy and in guiding appropriate management of the patient. There is limited literature regarding the use of shear wave elastography in ulnar nerve neuropathy. Our purpose was to evaluate the role of shear wave elastography in assessing stiffness changes within the ulnar nerve during treatment of leprosy.

METHODS

This was a prospective study which included 30 patients diagnosed with leprosy neuropathy. Recruited patients were followed up, during the course of treatment, i.e. for 1 year. Serial ultrasonography of these patients was done at 0, 3, 6 and 12 months interval.

RESULTS

Significant (P < 0.05) decrease in elastography parameters was seen in transverse imaging plane between first and third, as well as first and fourth visits (mean stiffness and velocity pretreatment ~ 25.78 ± 18 kPa and 2.74 ± 0.98 m/s, mean stiffness and velocity post-treatment 15.67 ± 5.89 kPa and 2.24 ± 0.428 m/s). Although elastography parameters decreased during these visits in the long-axis imaging plane, they were not found to be statistically significant. However, gross morphology and cross-sectional area of the nerve did not change significantly across visits. Interestingly, elastography values were higher in patients with neuritis, though not statistically significant.

CONCLUSION

Shear wave elastography is a novel, upcoming modality in musculoskeletal imaging especially in the evaluation of peripheral neuropathy. It can act as an adjunct to grey-scale imaging, which can help in early diagnosis and in guiding treatment of leprosy neuropathy.

Shear wave elastography of the ulnar nerve at the forearm

The study included 38 ulnar nerves in 20 healthy subjects. High-resolution ultrasound and Shear wave elastography were used to evaluate the ulnar nerve at the mid forearm. The mean cross-sectional area of the ulnar nerve was 7.1 mm2. The mean shear elastic modulus of the nerve in the short axis was 27.4 kPa. The mean shear elastic modulus of the nerve in long axis was 24.7 kPa. No statistical relation could be noted between elasticity measurements in long and short axes. The ulnar nerve elastic modulus also showed no correlation with CSA neither in the long axis nor short axis. Age, height, weight, and body mass index showed no correlation with the ulnar elastic modulus in short or long axes. The elastic modulus of the ulnar nerve has been determined in healthy subjects and can serve as a reference for future assessment of compressive neuropathies of the ulnar nerve.

Neuromas and postamputation pain

Postamputation stump and phantom pain are highly prevalent but remain a difficult condition to treat. The underlying mechanisms are not fully clarified, but growing evidence suggests that changes in afferent nerves, including the formation of neuromas, play an important role. The main objective of this cross-sectional study was to investigate whether ultrasound-verified neuroma swellings are more frequent in amputees with postamputation pain than in amputees without pain (primary outcome). Sixty-seven amputees were included. Baseline characteristics including the frequency and intensity of spontaneous stump and phantom pain were obtained, and sensory characteristics and evoked responses were assessed. A high-frequency ultrasound examination of the amputated extremity was performed to obtain information on the presence, size, and elasticity of swollen neuromas and pressure pain thresholds. Swollen neuromas were present in 53 (79.1%) of the 67 amputees included in the study, in 47 (82.5%) of 57 amputees with pain and in 6 (60.0%) of 10 amputees without pain (P = 0.2). No difference was found in stump pain intensity (P = 0.42) during the last week or in phantom pain intensity in the last month (P = 0.74) between amputees with and without swollen neuromas. Our findings suggest that it is not the presence of swollen neuromas itself that drives postamputation pain. However, changes in the transected nerve endings may still be crucial for driving postamputation pain because a positive Tinel sign was significantly more frequent in amputees with pain, irrespectively of the degree of neuroma swelling.

Application of High-Resolution Ultrasound on Diagnosing Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus (DM). The typical manifestation is a length-dependent "glove and sock" sensation. At present, diagnosis is mainly dependent on clinical manifestations. Since the pathogenesis is not clear, there are no effective treatment measures. Management consists mainly of glucose control, peripheral nerve nutrition, and other measures to delay the progress of the disease; early diagnosis is therefore crucial to improving prognosis and quality of life for patients with DPN. Due to the lack of obvious symptoms in 50% of patients and the low sensitivity of neuro-electrophysiology to small fibers, the missed diagnosis rate is high. High-resolution ultrasound (HRU), as a convenient noninvasive tool, has been proven by many studies to have excellent clinical value in diagnosing DPN. With the development of related new technology, HRU shows promise for the screening, diagnosing, and follow-up of DPN, which could serve as a biomarker and provide new diagnostic insights. In this paper, we review the ability of HRU to detect nerve cross-sectional area and blood flow, and echo and other image changes, and in showing the characteristics of peripheral nerve morphological changes in patients with DPN. We also explore the application of two other recent technological developments-shear wave elastography (SWE) and ultrasound scoring systems-in improving the diagnostic efficiency of HRU in peripheral neuropathy.

Shear wave elastography of the saphenous nerve

The purpose of this study is to study sonoelastographic features of the saphenous nerve.The study included 72 saphenous nerves in 36 healthy subjects. High resolution ultrasound and Shearwave elastography were used to evaluate the saphenous nerve. Cross sectional area (CSA) and stiffness were measured.The mean CSA of the saphenous nerve was 5.7 mm. The mean shear elastic modulus of the saphenous nerve in the short axis was 29.5 kPa. The mean shear elastic modulus of the saphenous nerve in long axis was 29.9 kPa. The saphenous nerve elastic modulus also showed no correlation with CSA in neither the long axis nor short axis. Positive correlation between elasticity measurements in the long and short axes. Age, height, weight, and BMI showed no correlation with saphenous nerve elastic modulus in short or long axes.The elastic modulus of the saphenous nerve has been determined in healthy subjects and can serve as a reference for future assessment of the saphenous nerve before different procedures.

Evaluation of the ulnar nerve with shear-wave elastography: a potential sonographic method for the diagnosis of ulnar neuropathy

PURPOSE

This study was designed to verify whether shear-wave elastography (SWE) can be used to differentiate ulnar neuropathy at the cubital tunnel from asymptomatic ulnar nerve or medial epicondylitis. An additional aim was to determine a cut-off value to identify patients with ulnar neuropathy.

METHODS

This study included 10 patients with ulnar neuropathy at the cubital tunnel as confirmed with electromyography (three women and seven men; mean age, 51.9 years), 10 patients with medial epicondylitis (nine women and one man; mean age, 56.1 years), and 37 patients with asymptomatic ulnar nerve and lateral epicondylitis (21 women and 16 men; mean age, 54.0 years). Each patient underwent SWE of the ulnar nerve at the cubital tunnel, distal upper arm, and proximal forearm.

RESULTS

Patients with ulnar neuropathy at the cubital tunnel exhibited significantly greater mean ulnar nerve stiffness at the cubital tunnel (66.8 kPa) than controls with medial epicondylitis (21.2 kPa, P=0.015) or lateral epicondylitis (33.9 kPa, P=0.040). No significant differences were observed between patients and controls with regard to ulnar nerve stiffness at the distal upper arm or the proximal forearm. A stiffness of 31.0 kPa provided 100% specificity, 80.0% sensitivity, 100% positive predictive value, and 83.3% negative predictive value for the differentiation between ulnar neuropathy and medial epicondylitis.

CONCLUSION

Cubital tunnel syndrome is associated with a stiffer ulnar nerve than lateral or medial epicondylitis. SWE seems to be a new, reliable, and simple quantitative diagnostic technique to aid in the precise diagnosis of ulnar neuropathy at the cubital tunnel.

A quantitative evaluation of sciatic nerve stiffness after compression by shear wave elastography in diabetic rats

Background

Our study investigates the feasibility of using quantitative evaluation for nerve entrapment visualization by shear wave elastography (SWE) in diabetic rats.

Methods

A total of 24 male Sprague-Dawley (SD) rats were included in this study. Before injection of streptozotocin (STZ), the experimental groups were assigned as the diabetic nerve compression (DNC) group (DNC, n=18) and the control group (CON, n=6). The DNC model was created by wrapping a silicone tube around the nerve, and then the DNC group was divided into the DNC 2-week (DNC2W, n=6), 4-week (DNC4W, n=6), and 8-week (DNC8W, n=6) groups according to the different duration time of sciatic nerve compression. The nerve stiffness was detected by SWE. Meanwhile, motor nerve conduction velocity (MNCV) was detected. These 2 indicators and histology of sciatic nerves were compared across the different groups.

Results

The stiffness of the nerve depicted by SWE at the compression site increased markedly along with the duration time of compression (P<0.01). The MNCV decreased along with the duration time of nerve compression (P<0.05). The nerve stiffness depicted by SWE was negatively correlated with MNCV (r=−0.926; P<0.01). Myelinated fiber density significantly decreased as the duration time of nerve compression increased (P<0.01). Some differences were found between DNC4W and DNC8W groups, and CON and DNC2W groups (P<0.05) in average axon diameter, myelin sheath thickness, and g ratio.

Conclusions

The increased values of SWE, along with the increased duration of nerve compression, could reflect the severity of nerve entrapment in diabetic rats. Therefore, SWE may be used as a noninvasive and effective method to quantitatively evaluate the severity of diabetic nerve entrapment.

Influence of limb position on assessment of nerve mechanical properties by using shear wave ultrasound elastography

INTRODUCTION

Evaluation of nerve mechanical properties has the potential to improve assessment of nerve impairment. Shear wave velocity, as measured by using shear wave (SW) ultrasound elastography, is a promising indicator of nerve mechanical properties such as stiffness. However, elucidation of external factors that influence SW velocity, particularly nerve tension, is required for accurate interpretations.

METHODS

Median and ulnar nerve SW velocities were measured at proximal and distal locations with limb positions that indirectly altered nerve tension.

RESULTS

Shear wave velocity was greater at proximal and distal locations for limb positions that induced greater tension in the median (mean increase proximal 89.3%, distal 64%) and ulnar (mean increase proximal 91.1%, distal 37.4%) nerves.

DISCUSSION

Due to the influence of nerve tension when SW ultrasound elastography is used, careful consideration must be given to limb positioning.

Cervical muscle diseases are associated with indefinite and various symptoms in the whole body

PURPOSE

Patients with various and indefinite symptoms in the whole body occasionally have coincident with stiffness or tenderness of the cervical muscles. This prospective case series examined the effect of local modulation of the cervical muscles in patients with cervical disorders reporting indefinite whole-body symptoms.

METHODS

A total of 1863 hospitalized patients with cervical disorders accompanying three or more indefinite whole-body symptoms, who were resistant to outpatient care, were enrolled in this study for 12 years. All patients underwent daily physical therapies to the cervical muscles during hospitalization. Self-rated records on the medical interview sheets documenting 30 representative symptoms including cervical/shoulder pain or stiffness and 28 representative indefinite whole-body symptoms at admission and discharge were compared across the population.

RESULTS

The number of symptoms decreased significantly with the local modulation of the cervical muscles during hospitalization. All of the 28 indefinite whole-body symptoms at admission showed recovery rates greater than 50% at discharge. The mean number of symptoms decreased significantly from 17.8 at admission to 7.4 at discharge (p < 0.0001). The percentages of patients reporting 10 or more symptoms were 91.1% and 29.3% at admission and discharge, respectively. Moreover, 8.2% of patients reported no residual symptoms at discharge.

CONCLUSION

Cervical muscle lesions may contribute to indefinite whole-body symptoms, possibly through dysfunction of the parasympathetic nervous system in the muscles. Local modulation of cervical muscles could lead to a breakthrough in the management of patients with indefinite whole-body symptoms.

TRIAL REGISTRATION ID

UMIN000035445. These slides can be retrieved under Electronic Supplementary Material.

Ultrasound elastography as a potential method to evaluate entrapment neuropathies in elite athletes: a mini-review

Entrapment neuropathies constitute a significant albeit still neglected problem in athletes. Currently available diagnostic options in patients with suspected neuropathies, nerve conduction studies, and magnetic resonance imaging have some drawbacks, mostly related to their invasive character, high cost, and limited availability. This paper reviews published articles documenting the use of ultrasound elastography, a novel technique to determine tissue strain, in the evaluation of nerve stiffness in entrapment neuropathy, and it discusses potential pros and cons of this method in the examination of elite athletes. Based on the review of literature, ultrasound elastography - especially shear wave elastography - seems suitable for the evaluation of entrapment neuropathies in elite athletes. Published evidence from the general population suggests that most common entrapment neuropathies (carpal tunnel syndrome, ulnar neuropathy of the elbow, ulnar tunnel syndrome) are associated with a significant increase in the stiffness of affected nerves, which can be accurately detected with ultrasound elastography. Before adding ultrasound elastography to the armamentarium of diagnostic tests used routinely in athletes, its accuracy in the detection of entrapment neuropathies needs to be verified in this specific group, and the reference values for peripheral nerve strain in sportspersons need to be determined.

Ultrasound elastography in the evaluation of peripheral neuropathies: a systematic review of the literature

Peripheral neuropathy is associated with an increase in intraneural pressure, and hence ultrasound elastography seems to be an ideal method to detect early stages of this condition based on changes in the affected nerve stiffness. The aim of this systematic review was to analyse the applicability of strain elastography (SE) and shear wave elastography (SWE) in the evaluation of peripheral nerves in patients with neuropathy of various aetiologies. Published evidence shows clearly that ultrasound elastography can accurately diagnose many types of peripheral neuropathies (carpal tunnel syndrome and other entrapment neuropathies, diabetic peripheral neuropathy and peripheral neuropathy associated with other systemic diseases), sometimes at the stages at which the condition is still asymptomatic. However, it is still unclear whether elastographic changes within the nerves precede functional anomalies detectable on nerve conduction studies. Also, relatively little is known about the relationship between the stiffness of peripheral nerves and the severity of peripheral neuropathy and its underlying condition. Based on the reproducibility data, SWE seems to be superior to SE. Nevertheless, the sources of heterogeneity in the peripheral nerve stiffness in healthy persons need to be identified, and the sets of reference values for specific peripheral nerves need to be determined. Finally, the potential confounding effect of hardening artefacts, such as bones, on the stiffness of peripheral nerves needs to be verified. After addressing all these issues, elastographic evaluation of peripheral nerve stiffness might become a reliable, easily accessible, and convenient diagnostic test performed routinely in patients with various peripheral neuropathies.

Ultrasound elastography for the evaluation of peripheral nerves: A systematic review

Peripheral nerve disorders are commonly encountered in clinical practice. Electrodiagnostic studies remain the cornerstone of the evaluation of nerve disorders. More recently, ultrasound has played an increasing complementary role in the neuromuscular clinic. Ultrasound elastography is a technique that measures the elastic properties of tissues. Given the histological changes that occur in diseased peripheral nerves, nerve ultrasound elastography has been explored as a noninvasive way to evaluate changes in nerve tissue composition. Studies to date suggest that nerve stiffness tends to increase in the setting of peripheral neuropathy, regardless of etiology, consistent with loss of more compliant myelin, and replacement with connective tissue. The aim of this systematic review is to summarize the current literature on the use of ultrasound elastography in the evaluation of peripheral neuropathy. Limitations of ultrasound elastography and gaps in current literature are discussed, and prospects for future clinical and research applications are raised.

Effect of intensive inpatient physical therapy on whole-body indefinite symptoms in patients with whiplash-associated disorders

BACKGROUND

A considerable number of patients with whiplash-associated disorders (WAD) report variable and indefinite symptoms involving the whole body, despite there being no evidence of direct injuries to organs other than the neck. However, little is known about their management or underlying mechanism. This study examined the effect of intensive physical therapy at the cervical muscles in patients with WAD reporting whole-body indefinite symptoms.

METHODS

A total of 194 hospitalized patients with WAD who were resistant to outpatient care by reporting whole-body indefinite symptoms between May 2006 and May 2017 were enrolled in this observational study. All patients underwent daily physical therapies by low-frequency electric stimulation therapy and far-infrared irradiation to the cervical muscles during hospitalization. Self-rated records in the medical interview sheets on 22 representative whole-body symptoms at admission and discharge were compared.

RESULTS

The number of symptoms was markedly decreased by the physical therapies during hospitalization. Almost all symptoms showed recovery rates of more than 80% at discharge as compared to those at admission. Although the percentage of patients reporting at least four of the 22 representative indefinite symptoms was 99.0% at admission, it decreased to 7.7% at discharge. Sixteen percent of patients recovered completely without any residual symptoms. The mean number of symptoms significantly decreased from 13.1 at admission to 2.0 at discharge. Notably, symptoms other than those in the neck or shoulder recovered to a greater extent than those in the neck or shoulder.

CONCLUSIONS

This study, for the first time, examined the management of whole-body indefinite symptoms in patients with WAD. The intensive physical therapy markedly improved the symptoms, suggesting the involvement of cervical muscles in the pathogenesis.

TRIAL REGISTRATION

UMIN000035435 (Retrospectively registered on Jan 3, 2019).

Ulnar nerve instability in the cubital tunnel of asymptomatic volunteers

PURPOSE

Ulnar nerve instability (UNI) in the cubital tunnel is defined as ulnar nerve subluxation or dislocation. It is a common disorder that may be noted in patients with neuropathy or in the asymptomatic. Our prospective, single-site study utilized high-resolution ultrasonography (US) to evaluate the ulnar nerve for cross-sectional area (CSA) and measures of shear-wave elastography (SWE). Mechanical algometry was obtained from the ulnar nerve in the cubital tunnel to assess pressure pain threshold (PPT).

METHODS

Forty-two asymptomatic subjects (n = 84 elbows) (25 males, 17 females) aged 22-40 were evaluated. Two chiropractic radiologists, both with 4 years of ultrasound experience performed the evaluation. Ulnar nerves in the cubital tunnel were sampled bilaterally in three different elbow positions utilizing US, SWE, and algometry. Descriptive statistics, two-way ANOVA, and rater reliability were utilized for data analysis with p ≤ 0.05.

RESULTS

Fifty-six percent of our subjects demonstrated UNI. There was a significant increase in CSA in subjects with UNI (subluxation: 0.066 mm² ± 0.024, p = 0.027; dislocation: 0.067 mm² ± 0.024, p = 0.003) compared to controls (0.057 mm² ± 0.017) in all three elbow positions. There were no significant group differences in SWE or algometry. Inter- and intra-observer agreements for CSA of the ulnar nerves within the cubital tunnel were assessed using intraclass correlation coefficient (ICC) and demonstrated moderate (ICC 0.54) and excellent (ICC 0.94) reliability.

CONCLUSIONS

Most of the asymptomatic volunteers demonstrated UNI. There was a significant increase in CSA associated with UNI implicating it as a risk factor for ulnar neuropathy in the cubital tunnel. There were no significant changes in ulnar nerve SWE and PPT. Intra-rater agreement was excellent for the CSA assessment of the ulnar nerve in the cubital tunnel. High-resolution US could be utilized to assess UNI and monitor for progression to ulnar neuropathy.