Peripheral nerve motion measurement with spectral Doppler sonography: a reliability study

Ultrasound Speckle Tracking Method Based on Gradient Optical Flow to Quantify Small Longitudinal Displacement, Shear and Longitudinal Strain in Peripheral Nerves

OBJECTIVE

This study aimed to develop, validate and test the clinical feasibility of ultrasound (US) speckle tracking method based on gradient optical flow for quantifying small longitudinal displacements, shear and strain in peripheral nerves.

METHODS

The speckle tracking method was validated using seven thawed, fresh-frozen isolated cadaveric forearms. Longitudinal motion of the median nerve was captured using a high-frequency 22 MHz linear probe. An air bubble marker was inserted as a reference point for manual measurement comparison. The precision and accuracy of the method were assessed by comparing manual and automatic measurements. Clinical feasibility was tested on eight healthy subjects, measuring the longitudinal displacement of the median nerve during elbow extension and shoulder anteflexion.

RESULTS

The method demonstrated linearity, high precision and accuracy, particularly with a backtrace of five frames, reducing the displacement underestimation to 4%. In cadaveric models, the highest shear strain was observed at the nerve-tissue interfaces. In healthy subjects, the mean displacement of the median nerve was 3.3 ± 1.0 mm, with good inter-rater reliability (intraclass correlation coefficient = 0.87).

CONCLUSION

The US speckle tracking method based on gradient optical flow effectively quantifies small longitudinal displacements and shear strain in peripheral nerves, with high precision and accuracy. However, the method could not detect longitudinal strain in nerves within the range of tested displacements. Future studies should investigate its applicability to smaller and deeper nerves and its usefulness in different pathological conditions.

Multiparametric Ultrasound Assessment of Carpal Tunnel Syndrome: Beyond Nerve Cross-sectional Area

Carpal tunnel syndrome (CTS), the most common mononeuropathy, results from compression of the median nerve within the fibro-osseous carpal tunnel. Diagnosis is typically based on clinical evaluation and confirmed by nerve conduction studies. However, ultrasound (US) has emerged as a valuable noninvasive adjunct for CTS confirmation, offering potential advantages over electrodiagnostic testing in terms of patient comfort and diagnostic accuracy. This review begins with a concise summary of carpal tunnel anatomy and CTS pathophysiology as a foundation for exploring the diverse applications of US in CTS evaluation. B-mode US assessment is presented with a focus on cross-sectional imaging and dynamic evaluations, including the transverse translocation and longitudinal gliding of the median nerve. We also review current methods for assessing vascularization in CTS and explore the usefulness of elastography in CTS evaluation. The advantages and limitations of each US method are elucidated, highlighting their practical utility in clinical practice.

Changes in Ultrasound Parameters of the Median Nerve at Different Positions of the Radiocarpal Joint in Patients with Carpal Tunnel Syndrome

Ultrasound imaging (US) is being increasingly used to aid in the diagnosis of entrapment neuropathies. This study aims to evaluate the shear modulus and cross-sectional area (CSA) of the median nerve in patients with carpal tunnel syndrome (CTS). A total of 35 patients with CTS participated in the study. CSA and shear modulus testing were performed in shear wave elastography (SWE) mode in five positions of the right and left radiocarpal joints (intermediate position 0°, 45° of extension, maximum extension, 45° of flexion, and maximum flexion). There were significant side-to-side differences in the median nerve shear modulus at each wrist position as compared to the asymptomatic side. There were significant side-to-side differences in the median nerve CSA at each wrist position as compared to the asymptomatic side. Shear modulus increases in patients with CTS at different angular positions of flexion and extension of the radiocarpal joint. In individuals with CTS, the CSA of the median nerve is greater on the symptomatic side compared to the asymptomatic side. The CSA decreases in positions of maximum extension and 45° of flexion and in maximum flexion relative to the resting position.

Neurofascialvascular training for carpal tunnel syndrome as an evolution of neurodynamic treatment: A case report

INTRODUCTION

In this case report a new approach called neurofascialvascular training (NFVT) is described. NFVT consists of two mechanisms which improve mechanosensitivity in carpal tunnel syndrome (CTS). The first involves increased blood flow in the nerve microcirculation, while the second stimulates the reciprocal sliding between the thin sheets of connective tissue inside the nerve. The goal of these two actions is to squeeze, mobilize and reduce intraneural edema. The novelty of this approach is the simultaneous involvement of multiple physiological systems to reduce nerve mechanosensitivity. This case report describes the rehabilitation progress achieved by NFVT in a patient with CTS.

MAIN SYMPTOMS AND/OR IMPORTANT CLINICAL FINDINGS

A 64-year-old woman complaining of nocturnal pain and tingling with severe impairment of sleep quality for two years was diagnosed at CTS.

THERAPEUTIC INTERVENTIONS

The patient underwent nine 30-min exercise sessions of NFVT.

OUTCOMES

At each session and at the last follow-up 3 months after the end of treatment the following tests were performed: the upper limb neurodynamic test1 (ULNT1), the Hand Grip Meter and the Phdurkan test. Furthermore ultrasound, numerical rating scale and the Boston Carpal Tunnel Questionnaire (BCTQ) were also adopted.

CONCLUSION

NFVT can improve symptoms and motor dysfunction in a patient with CTS.

TAKE-AWAY LESSON

In the presence of mild carpal tunnel syndrome, active neurofascialvascular training that increases peripheral blood flow and targets fascial tissue within the peripheral nervous system can resolve symptoms and produce significant improvement within a few months of starting treatment.

Effects of wrist extension on median nerve and flexor tendon excursions in patients with carpal tunnel syndrome: a case control study

Background

Reduced gliding ability of the median nerve in the carpal tunnel has been observed in patients with carpal tunnel syndrome (CTS). The purpose of this study was to evaluate the gliding abilities of the median nerve and flexor tendon in patients with CTS and healthy participants in the neutral and 30° extended positions of the wrist and to compare the gliding between the finger flexion and extension phases.

Methods

Patients with CTS and healthy participants were consecutively recruited in a community hospital. All the subjects received the Boston CTS questionnaire, physical examinations, nerve conduction study (NCS), and ultrasonography of the upper extremities. Duplex Doppler ultrasonography was performed to evaluate the gliding abilities of the median nerve and flexor tendon when the subjects continuously moved their index finger in the neutral and 30° extension positions of the wrist.

Results

Forty-nine patients with CTS and 48 healthy volunteers were consecutively recruited. Significant differences in the Boston CTS questionnaire, physical examination and NCS results and the cross-sectional area of the median nerve were found between the patients and the healthy controls. The degree of median nerve gliding and the ratio of median nerve excursion to flexor tendon excursion in the CTS group were significantly lower than those in the healthy control group in both the neutral and 30° wrist extension positions. Significantly increased excursion of both the median nerve and flexor tendon from the neutral to the extended positions were found in the CTS group. The ratio of median nerve excursion to flexor tendon excursion was significantly higher in the finger flexion phase than in the extended phase in both groups, and this ratio had mild to moderate correlations with answers on the Boston CTS Questionnaire and with the NCS results.

Conclusions

Reduced excursion of the median nerve was found in the patients with CTS. The ratio of median nerve excursion to flexor tendon excursion was significantly lower in the patients with CTS than in the healthy volunteers. The median nerve excursion was increased while the wrist joint was extended to 30° in the patients with CTS. Wrist extension may be applied as part of the gliding exercise regimen for patients with CTS to improve median nerve mobilization.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04349-8.

Comparison of two manual therapy techniques in patients with carpal tunnel syndrome: A randomized clinical trial

Background

Manual therapy techniques are part of physiotherapy treatment of carpal tunnel syndrome (CTS) which are classified into two groups including nerve mobilization and mechanical interface mobilization. The aim of the study was to find which manual therapy method-technique directed to mechanical interface and nerve mobilization-has superior beneficial effects on clinical and electrophysiological findings in conservative management of patients with CTS.

Methods

Thirty patients with CTS participated into two groups namely: mechanical interface and nerve mobilization in this randomized clinical trial. The intervention was performed three times weekly for 4 weeks. Mechanical interface mobilization was directed to structures around the median nerve at the forearm and wrist. Techniques of median nerve gliding and tension were used in the nerve mobilization group. The outcome measures included visual analogue scale (VAS), symptom severity scale (SSS), hand functional status scale (FSS) and motor and sensory distal latencies of median nerve. Paired t-test and ANCOVA were used for statistical analysis.

Results

At the end of the 4^th week of the treatment, the mean of VAS, SSS and FSS significantly improved in both groups (p<0.05), but the difference was not significant between the two groups (P>0.05). Although the mean of motor and sensory distal latencies of median nerve at the end of the treatment period only improved in the nerve mobilization group (p<0.05), the difference was not significant between the two groups (P>0.05).

Conclusion

Mechanical interface mobilization and nerve mobilization techniques are not superior to each other in reducing pain and improving hand symptoms and functional status.

Neurodynamic Techniques Versus "Sham" Therapy in the Treatment of Carpal Tunnel Syndrome: A Randomized Placebo-Controlled Trial

OBJECTIVE

To evaluate the efficacy of neurodynamic techniques used as the sole therapeutic component compared with sham therapy in the treatment of mild and moderate carpal tunnel syndromes (CTS).

DESIGN

Single-blinded, randomized placebo-controlled trial.

SETTING

Several medical clinics.

PARTICIPANTS

Volunteer sample of patients (N=250) diagnosed with CTS (n=150).

INTERVENTIONS

Neurodynamic techniques were used in the neurodynamic techniques group, and sham therapy was used in the sham therapy group. In the neurodynamic techniques group, neurodynamic sequences were used, and sliding and tension techniques were also used. In the sham therapy group, no neurodynamic sequences were used, and therapeutic procedures were performed in an intermediate position. Therapy was conducted twice weekly for a total of 20 therapy sessions.

MAIN OUTCOME MEASURES

Symptom severity (symptom severity scale) and functional status (functional status scale) of the Boston Carpal Tunnel Questionnaire.

RESULTS

A baseline assessment revealed no intergroup differences in all examined parameters (P>.05). After therapy, there was statistically significant intragroup improvement in nerve conduction study (sensory and motor conduction velocity and motor latency) only for the neurodynamic techniques group (P<.01). After therapy, intragroup statistically significant changes also occurred for the neurodynamic techniques group in pain assessment, 2-point discrimination sense, symptom severity scale, and functional status scale (in all cases P<.01). There were no group differences in assessment of grip and pinch strength (P>.05).

CONCLUSIONS

The use of neurodynamic techniques has a better therapeutic effect than sham therapy in the treatment of mild and moderate forms of CTS.

Assessing the Reliability of Ultrasound Imaging to Examine Peripheral Nerve Excursion: A Systematic Literature Review

Ultrasound imaging (USI) is gaining popularity as a tool for assessing nerve excursion and is becoming an important tool for the assessment and management of entrapment neuropathies. This systematic review aimed to identify current methods and report on the reliability of using USI to examine nerve excursion and identify the level of evidence supporting the reliability of this technique. A systematic search of five electronic databases identified studies assessing the reliability of using USI to examine nerve excursion. Two independent reviewers critically appraised and assessed the methodological quality of the identified articles. Eighteen studies met the eligibility criteria. The majority of studies were of "moderate" or "high" methodological quality. The overall analysis indicated a "strong" level of evidence of moderate to high reliability of using USI to assess nerve excursion. Further reliability studies with consistency of reporting are required to further strengthen the level of evidence.

In vivo effects of limb movement on nerve stretch, strain, and tension: A systematic review

BACKROUND

The mechanical behavior of the peripheral nervous system under elongation and tension has not been adequately established in vivo.

OBJECTIVE

The purpose of this review is to investigate the mechanical behavior of the peripheral nervous system in vivo.

METHODS

In vivo studies which evaluated the effects of limb movement and neurodynamic tests on peripheral nerve biomechanics were systematically searched in PubMed (Medline), the Cochrane Database, CINAHL, PEDro, Embase and Web of Science. Studies fulfilling the search criteria were assessed for methodological quality with a modified version of the Down & Blacks scale by two reviewers.

RESULTS

This review includes the results of 22 studies, of which 15 examined limb movement influencing the median nerve, four the sciatic nerve, two the tibial nerve; and one each the ulnar and peroneal nerves respectively. Substantial nerve longitudinal and transverse excursion and changes in diameter were reported. Despite this, increased nerve strain was not a major finding.

CONCLUSION

The heterogeneity of included studies, including wide variety of nerves tested, measurement location and joint position prevented comparisons between studies and also amalgamation of data. Limb movement induces complex biomechanical effects of which nerve elongation plays only a minor role.

Assessment of Median Nerve Mobility by Ultrasound Dynamic Imaging for Diagnosing Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy and is characterized by median nerve entrapment at the wrist and the resulting median nerve dysfunction. CTS is diagnosed clinically as the gold standard and confirmed with nerve conduction studies (NCS). Complementing NCS, ultrasound imaging could provide additional anatomical information on pathological and motion changes of the median nerve. The purpose of this study was to estimate the transverse sliding patterns of the median nerve during finger movements by analyzing ultrasound dynamic images to distinguish between normal subjects and CTS patients. Transverse ultrasound images were acquired, and a speckle-tracking algorithm was used to determine the lateral displacements of the median nerve in radial-ulnar plane in B-mode images utilizing the multilevel block-sum pyramid algorithm and averaging. All of the averaged lateral displacements at separate acquisition times within a single flexion–extension cycle were accumulated to obtain the cumulative lateral displacements, which were curve-fitted with a second-order polynomial function. The fitted curve was regarded as the transverse sliding pattern of the median nerve. The R² value, curvature, and amplitude of the fitted curves were computed to evaluate the goodness, variation and maximum value of the fit, respectively. Box plots, the receiver operating characteristic (ROC) curve, and a fuzzy c-means clustering algorithm were utilized for statistical analysis. The transverse sliding of the median nerve during finger movements was greater and had a steeper fitted curve in the normal subjects than in the patients with mild or severe CTS. The temporal changes in transverse sliding of the median nerve within the carpal tunnel were found to be correlated with the presence of CTS and its severity. The representative transverse sliding patterns of the median nerve during finger movements were demonstrated to be useful for quantitatively estimating median nerve dysfunction in CTS patients.

Quantitative in vivo longitudinal nerve excursion and strain in response to joint movement: A systematic literature review

BACKGROUND

Neural system mobilization is widely used in the treatment of several painful conditions. Data on nerve biomechanics is crucial to inform the design of mobilization exercises. Therefore, the aim of this review is to characterize normal nervous system biomechanics in terms of excursion and strain.

METHODS

Studies were sought from Pubmed, Physiotherapy Evidence Database, Cochrane Library, Web of Science and Scielo. Two reviewers' screened titles and abstracts, assessed full reports for potentially eligible studies, extracted information on studies' characteristics and assessed its methodological quality.

FINDINGS

Twelve studies were included in this review that assessed the median nerve (n=8), the ulnar nerve (n=1), the tibial nerve (n=1), the sciatic nerve (n=1) and both the tibial and the sciatic nerves (n=1). All included studies assessed longitudinal nerve excursion and one assessed nerve strain. Absolute values varied between 0.1mm and 12.5mm for median nerve excursion, between 0.1mm and 4.0mm for ulnar nerve excursion, between 0.7 mm and 5.2mm for tibial nerve excursion and between 0.1mm and 3.5mm for sciatic nerve excursion. Maximum reported median nerve strain was 2.0%.

INTERPRETATION

Range of motion for the moving joint, distance from the moving joint to the site of the lesion, position of adjacent joints, number of moving joints and whether joint movement stretches or shortens the nerve bed need to be considered when designing neural mobilization exercises as all of these factors seem to have an impact on nerve excursion.

Effects of neuromobilization maneuver on clinical and electrophysiological measures of patients with carpal tunnel syndrome

[Purpose] The aim of this study was to investigate the efficacy of neuromobilization combined with routine physiotherapy in patients with carpal tunnel syndrome through subjective, physical, and electrophysiological studies. [Subjects and Methods] Twenty patients with carpal tunnel syndrome (totally 32 hands) were assigned two groups: treatment and control groups. In both groups, patients received the routine physiotherapy. In addition to the routine physiotherapy, patients in the treatment group received neuromobilization. The symptoms severity scale, visual analogue scale, functional status scale, Phalen’s sign, median nerve tension test, and median nerve distal sensory and motor latency were assessed. [Results] There were significant improvements in the symptoms severity scale, visual analogue scale, median nerve tension test, and Phalen’s sign in both groups. However, the functional status scale and median nerve distal motor latency were significantly improved only in the treatment group. [Conclusion] Neuromobilization in combination with routine physiotherapy improves some clinical findings more effectively than routine physiotherapy. Therefore, this combination can be used as an alternative effective non-invasive treatment for patients with carpal tunnel syndrome.

Dynamic analysis of the ulnar nerve in the cubital tunnel using ultrasonography

BACKGROUND

We investigated the dynamics of the ulnar nerve during elbow flexion and the relationships between these dynamics and the morphology of the ulnar nerve groove in healthy individuals.

MATERIALS AND METHODS

Twenty healthy volunteers (40 elbows) underwent ultrasonographic examination of the ulnar nerve at the elbow. We measured the breadth and depth of the ulnar nerve groove at 90° of elbow flexion and calculated the depth-to-breadth ratio. We recorded the distance from the trochlea of the humerus to the nerve and the short-axis diameter of the nerve at 30°, 60°, 90°, and 120° of elbow flexion. We calculated the medial shift and flattening of the ulnar nerve at each angle relative to 30° of flexion, compared the values among the different angles, and compared the depth-to-breadth ratio with the location, medial shift, and flattening ratio of the ulnar nerve.

RESULTS

The medial shift was significantly greater at 120° than at other angles (P < .001). Flattening increased with increasing elbow flexion and was significantly different at 60°, 90°, and 120° (all P < .001). The flattening ratios were significantly correlated with the depth-to-breadth ratio at 120° (r = -0.43, P = .005).

CONCLUSIONS

The ulnar nerve moves medially and is flattened with the elbow flexed between 90° and 120°. When the ulnar nerve groove is shallow, high degrees of elbow flexion result in flattening of the ulnar nerve in the groove.

The deformation and longitudinal excursion of median nerve during digits movement and wrist extension

The use of electronic devices, such as mobile phones and computers, has increased drastically among the young generation, but the potential health effects of carpal tunnel syndrome (CTS) on university students has not been comprehensively examined. Thirty-one university students aged 18 to 25 y with no symptoms of CTS were successfully recruited in this study. By using noninvasive ultrasonography, the morphological characteristics of the median nerve of each volunteer, and the extent of its longitudinal excursion movement under experimental conditions, in which a real operating environment of electronic devices was simulated, were quantified. The results demonstrated that the median nerve at the carpal tunnel inlet was flattened during wrist extension: the flattening ratio increased from 3.40 ± 0.91 at the neutral position to 4.10 ± 1.11 at the angle of 30° and 4.09 ± 1.11 at the angle of 45°. In addition, the median nerve became swollen after the students performed rapid mobile-phone keying for 5 min, indicated by a significant increase in the cross-sectional area from 6.05 ± 0.97 mm(2) to 7.56 ± 1.39 mm(2). Passive longitudinal excursion was observed at the median nerve when the students performed mouse-clicking (2.4 ± 1.0 mm) and mobile-phone keying tasks (1.7 ± 0.6 mm), with the mouse-clicking task generating a greater extent of longitudinal excursion than the mobile-phone keying task did. In conclusion, the findings of the present study verify the potential harm caused by using electronic devices while maintaining an inappropriate wrist posture for a substantial period.

Comparison of the effects of flexion and extension of the thumb and fingers on the position and cross-sectional area of the median nerve

Objective

To assess the separate effects of thumb and finger extension/flexion on median nerve position and cross-sectional area.

Methods

Ultrasonography was used to assess median nerve transverse position and cross-sectional area within the carpal tunnel at rest and its movement during volitional flexion of the individual digits of the hand. Both wrists of 165 normal subjects (11 men, 4 women, mean age, 28.6, range, 22 to 38) were studied.

Results

Thumb flexion resulted in transverse movement of the median nerve in radial direction (1.2±0.6 mm), whereas flexion of the fingers produced transverse movement in ulnar direction, which was most pronounced during flexion of the index and middle fingers (3.2±0.9 and 3.1±1.0 mm, respectively). Lesser but still statistically significant movements were noted with flexion of the ring finger (2.0±0.8 mm) and little finger (1.2±0.5 mm). Flexion of the thumb or individual fingers did not change median nerve cross-sectional area (8.5±1.1 mm²).

Conclusions

Volitional flexion of the thumb and individual fingers, particularly the index and middle fingers, produced significant transverse movement of the median nerve within the carpal tunnel but did not alter the cross-sectional area of the nerve. The importance of these findings on the understanding of the pathogenesis of the carpal tunnel syndrome and its treatment remains to be investigated.

Tibial nerve excursion during lumbar spine and hip flexion measured with diagnostic ultrasound

Ultrasound imaging provides a method for non-invasive in vivo measurement of nerve motion resulting from joint movement. This study measured the proximal excursion of the tibial branch of the sciatic nerve at the popliteal fossa during forward bending in healthy subjects. Long-axis image sequences of the nerve were analysed using frame-by-frame cross-correlation software that calculated the longitudinal and axial movement of the nerve. Proximal excursion was calculated from the hypotenuse of these values. The mean proximal excursion recorded was 12.2 mm (SD 2.2 mm, n = 24). The reliability of three repeat measurements was found to be excellent (ICC 0.97, 95% CI 0.93-0.99; SEM 0.7 mm, n = 21). The protocol described provides a reliable method for analysing tibial nerve movement that could prove useful in future clinical studies.

The validity of upper-limb neurodynamic tests for detecting peripheral neuropathic pain

The validity of upper-limb neurodynamic tests (ULNTs) for detecting peripheral neuropathic pain (PNP) was assessed by reviewing the evidence on plausibility, the definition of a positive test, reliability, and concurrent validity. Evidence was identified by a structured search for peer-reviewed articles published in English before May 2011. The quality of concurrent validity studies was assessed with the Quality Assessment of Diagnostic Accuracy Studies tool, where appropriate. Biomechanical and experimental pain data support the plausibility of ULNTs. Evidence suggests that a positive ULNT should at least partially reproduce the patient's symptoms and that structural differentiation should change these symptoms. Data indicate that this definition of a positive ULNT is reliable when used clinically. Limited evidence suggests that the median nerve test, but not the radial nerve test, helps determine whether a patient has cervical radiculopathy. The median nerve test does not help diagnose carpal tunnel syndrome. These findings should be interpreted cautiously, because diagnostic accuracy might have been distorted by the investigators' definitions of a positive ULNT. Furthermore, patients with PNP who presented with increased nerve mechanosensitivity rather than conduction loss might have been incorrectly classified by electrophysiological reference standards as not having PNP. The only evidence for concurrent validity of the ulnar nerve test was a case study on cubital tunnel syndrome. We recommend that researchers develop more comprehensive reference standards for PNP to accurately assess the concurrent validity of ULNTs and continue investigating the predictive validity of ULNTs for prognosis or treatment response.

Morphologic Characterization of Intraneural Flow Associated With Median Nerve Pathology

A prospective cohort of 47 symptomatic patients who reported for nerve conduction studies and 44 asymptomatic controls was examined with sonography to evaluate the median nerve. Doppler studies of the median nerve were collected with handheld sonography equipment and a 12-MHz linear broadband transducer. Strict inclusion criteria were established for assessing 435 waveforms from 166 wrists. Two sonographers agreed that 245 waveforms met the a priori criteria and analyzed the corresponding data. Spectral Doppler waveforms provided direct quantitative and qualitative data for comparison with indirect provocative testing results. These Doppler data were compared between the recruitment groups. No statistical difference existed in waveforms between the groups (P < .05). Trending of the overall data indicated that as the number of positive provocative tests increased, the mean peak systolic velocity within the carpal tunnel (mid) also increased, whereas the proximal mean peak systolic velocity decreased. However, by using multiple provocative tests as an indirect comparative measure, researchers may find mean peak spectral velocity at the carpal tunnel inlet a helpful direct measure in identifying patients with carpal tunnel syndrome.

Speckle tracking ultrasound for assessment of the relative motion of flexor tendon and subsynovial connective tissue in the human carpal tunnel

The objective of this study was to compare tissue Doppler imaging and speckle tracking ultrasound to assess the relative motion of flexor tendon and surrounding subsynovial connective tissue (SSCT). Twenty normal human wrists were imaged with an ultrasound scanner. The two ultrasound methods measured the excursion and maximum velocity of the tendon and SSCT while subjects gripped three different sized acrylic tubes and these were correlated with tendon excursions estimated from finger joint angle changes. The maximum velocity ratio (=SSCT/tendon velocity) and the shear index (=[(Tendon excursion-SSCT excursion)/Tendon excursion]x100%) were calculated. The intraclass correlation coefficient was higher for joint angle/speckle tracking tendon excursion (0.642) than for joint angle/tissue Doppler excursion (0.377). The speckle tracking method could also discriminate differences in maximum velocity ratio and shear index for different tube sizes. We conclude that speckle tracking may be useful in assessing the relative motion of tendon and SSCT.

The excursion of the median nerve during nerve gliding exercise: an observation with high-resolution ultrasonography

The purpose of this study was to assess the relationship between the positioning of upper extremity and gliding distance of the median nerve during passive and active motion of the wrist and fingers. The longitudinal gliding of the medial nerve in the forearm was measured in 34 healthy subjects by ultrasonographic dynamic images. Those images were analyzed in a cross-correlation algorithm advocated by Dilley et al. (2001). In this experiment, passive extension of the wrist and fingers was applied manually by an examiner in four positions (elbow flexion and extension with forearm pronation, and elbow flexion and extension with forearm supination), two types of active finger motions (Hook and Grasp) were performed by the subjects. The distally oriented median nerve gliding ranged from 1.9 (in elbow extension with forearm pronation) to 3.0mm (in elbow flexion with forearm supination) during passive extension of the wrist and fingers. There was a statistically significant difference in nerve gliding between the positions (p=0.001). During active digital movement, the proximally oriented nerve gliding was observed from 0.8 (in the hook) to 1.3mm (in the grasp). There was a significant difference in nerve gliding between the two ways of active finger motions (p=0.001). On the basis of the data obtained from this study, it is concluded that forearm supination is the preferred position for the passive median nerve gliding exercise because of large distally oriented nerve gliding. The active digital motion with full finger grip may be an effective procedure to produce proximally oriented median nerve gliding.

Reliability of measuring sciatic and tibial nerve movement with diagnostic ultrasound during a neural mobilisation technique

Diagnostic ultrasound provides a technique whereby real-time, in vivo analysis of peripheral nerve movement is possible. This study measured sciatic nerve movement during a "slider" neural mobilisation technique (ankle dorsiflexion/plantar flexion and cervical extension/flexion). Transverse and longitudinal movement was assessed from still ultrasound images and video sequences by using frame-by-frame cross-correlation software. Sciatic nerve movement was recorded in the transverse and longitudinal planes. For transverse movement, at the posterior midthigh (PMT) the mean value of lateral sciatic nerve movement was 3.54 mm (standard error of measurement [SEM] +/- 1.18 mm) compared with anterior-posterior/vertical (AP) movement of 1.61 mm (SEM +/- 0.78 mm). At the popliteal crease (PC) scanning location, lateral movement was 6.62 mm (SEM +/- 1.10 mm) compared with AP movement of 3.26 mm (SEM +/- 0.99 mm). Mean longitudinal sciatic nerve movement at the PMT was 3.47 mm (SEM +/- 0.79 mm; n = 27) compared with the PC of 5.22 mm (SEM +/- 0.05 mm; n = 3). The reliability of ultrasound measurement of transverse sciatic nerve movement was fair to excellent (Intraclass correlation coefficient [ICC] = 0.39-0.76) compared with excellent (ICC = 0.75) for analysis of longitudinal movement. Diagnostic ultrasound presents a reliable, noninvasive, real-time, in vivo method for analysis of sciatic nerve movement.

Reduced longitudinal excursion of the median nerve in carpal tunnel syndrome

OBJECTIVE

To determine if longitudinal excursion of the median nerve is reduced in patients with carpal tunnel syndrome (CTS).

DESIGN

Case-control study.

SETTING

University human movement laboratory.

PARTICIPANTS

Nineteen patients with CTS (8 men, 11 women; mean age, 57+/-15 y), and 37 healthy controls (8 men, 29 women; mean age, 48+/-10 y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Longitudinal excursion of the median nerve, and the ratio of nerve to flexor digitorum superficialis tendon excursion at the carpal tunnel evoked by finger extension. Measurements were taken using a validated Doppler ultrasound technique, and tests were conducted with the elbow positioned in extension and flexion.

RESULTS

Mean longitudinal excursion of the median nerve was significantly greater in controls (11.2+/-2.8 mm) than patients (8.3+/-2.6 mm) with the elbow extended (P=.013), but not with the elbow flexed (controls, 12.5+/-2.5 mm; patients, 10.2+/-3.1 mm; P=.089). Mean nerve/tendon excursion ratios were significantly greater in controls (.32+/-.07) than patients (.23+/-.06), with the elbow extended (P<.001), and flexed (controls, .36+/-.06; patients, .28+/-.10; P=.019). Discriminant analysis identified that 11 (58%) of the 19 patients and 3 (8%) of the 37 controls showed a nerve/tendon excursion ratio of .25 or less when tested with the elbow in extension.

CONCLUSIONS

Reduced longitudinal excursion of the median nerve at the carpal tunnel was identified in a substantial proportion of patients with CTS. Further studies are merited to determine if reduced median nerve excursion at the carpal tunnel is clinically relevant in CTS, and can be influenced by movement-based interventions.

[Relationship between adverse neural tension and nerve conduction studies in patients with symptoms of the carpal tunnel syndrome]

The purpose of this study was to evaluate, through a series of cases, the relationship between the adverse neural tension of median nerve (ANTm) and the electrophysiological involvement in 38 patients with symptoms of the carpal tunnel syndrome (CTS), submitted to nerve conduction studies (NCS). The main measures had been ANTm (in degrees) obtained through the test of neural tension provocation (TNTP) and parameters of the NCS, divided into three groups: normal, without severe electrophysiological alteration and with severe electrophysiological alteration. Significant correlations were found between ANTm and parameters of the NCS (p<0.05), as well as between ANTm and the three groups defined by the electrophysiologic alteration (rs=+0.437, p=0.002). The TNAm values were significantly higher in the arms with electrophysiologic diagnoses (p=0.007). It is suggested that the ANTm does have a participation in the physiopathology of the CTS, and the use of therapeutical procedures that diminish the development of neural tension.

Ultrasound of nerve and muscle

Over the last two decades, ultrasound has developed into a useful technology for the evaluation of diseases of nerve and muscle. Since it is currently not used at by the majority of clinicians involved in diagnosis or care of patients with neuromuscular disorders, this review briefly describes the technical aspects of ultrasound and its physical principles. It relates normal muscle anatomy and movement to ultrasound images in the axial and sagittal planes and follows with a discussion of ultrasound findings in chronic muscle disease. These include evident atrophy and the loss of the hypoechoic architecture of normal muscle tissue. It highlights evolving uses of the technique to measure other pathologic changes in disease including altered muscle dynamics. With high-resolution instruments nerve imaging has now become standard, and the relationships of median nerve anatomy and observations of static and dynamic images from ultrasound are reviewed. Changes seen in carpal tunnel syndrome include significant increases in the cross-sectional area of the nerve just proximal to the site of compression, loss of hyperechoic intensities within nerve, and reduced mobility. Preliminary use of the technique for the study of other nerves is reviewed as well. Ultrasound is an ideal tool for the clinical and research investigation of normal and diseased nerve and muscle complementary to existing diagnostic techniques. As the technology continues to evolve, it will likely assume a more significant role in these areas as those most able to exploit its potential, clinical neurophysiologists and neuromuscular clinicians, incorporate its use at the bedside.

The carpal tunnel: ultrasound display of normal imaging anatomy and pathology

Ultrasound successfully displays the normal anatomy and pathology of the median nerve in the carpal tunnel. This article reviews the sonographic characteristics of carpal tunnel anatomy, including the superficially situated median nerve, the contained tendons and vessels, and the boundary-forming fibro-osseous landmarks. It emphasizes ultrasound evaluation of the median nerve and the criteria for diagnosis of compressive neuropathy in carpal tunnel syndrome. The techniques for performing sonography for carpal tunnel syndrome are detailed. Ultrasonic imaging is more comfortable for patients, less time-consuming, and less expensive than MR imaging, and achieves equal accuracy in skilled hands.

Chapter 25 Imaging nerve and muscle with ultrasound

Over the last two decades significant advances in ultrasound have made it possible for investigators to image and interpret pathologic changes in muscle and nerve. In addition to being able to assess the pathologic changes in these structures themselves, ultrasound also provides the unique ability to identify anatomic lesions responsible for nerve or muscle injury. They can be correlated with changes in neural structures or affected muscles. Like electrodiagnostic studies, ultrasound is portable and inexpensive, but it is even less invasive, and surprisingly sensitive in detecting a variety of unusual and common causes of neuromuscular dysfunction. Given recent developments in the field, ultrasound shows promise as the technique most suitable for clinical neurophysiologists and neuromuscular clinicians in the growing field of imaging. Such involvement is required to best adopt and exploit the potential of imaging for the research and clinical evaluation of neuromuscular disorders.

Longitudinal sliding of the median nerve in patients with carpal tunnel syndrome

In nerve compression syndromes restricted nerve sliding may lead to increased strain, possibly contributing to symptoms. Ultrasound was used to examine longitudinal median nerve sliding in 17 carpal tunnel syndrome patients and 19 controls during metacarpophalangeal joint movement. Longitudinal movement in the forearm averaged 2.62 mm in controls and was not significantly reduced in carpal tunnel syndrome (CTS) patients (mean=2.20 mm). In contrast, CTS patients had a 40% reduction in transverse nerve movement at the wrist on the most, compared to least, affected side and nerve areas were enlarged by 34%. Normal longitudinal sliding in the patients indicates that nerve strain is not increased and will not contribute to symptoms.

Repeatability of power Doppler sonography of cervical lymph nodes

This study was undertaken to investigate the repeatability (intraobserver variability) of power Doppler sonography in assessment of cervical lymph nodes. Power Doppler sonography was performed twice in 20 healthy subjects to evaluate the repeatability of measurement of size, blood flow velocity (peak systolic velocity, PSV, and end diastolic velocity, EDV) and vascular resistance (resistance index, RI, and pulsatility index, PI) of cervical nodes. A total of 70 power Doppler sonograms were reviewed to evaluate the repeatability of assessment of vascular pattern, degree of vascularity and displacement of vessels of cervical lymphadenopathy. In the 20 subjects, 139 normal cervical nodes were detected in the first scan and they were re-scanned in the second scan. One node was detected in the second scan, but not in the first scan. Of the total, 50 cervical nodes showed arterial flow in both scans, and blood flow velocity and vascularity resistance were measured. The mean value of PSV, EDV, RI and PI have a higher repeatability than their highest and lowest values. There is a high repeatability in the measurement of maximum transverse diameter (97%), mean PSV (95%), mean EDV (96%), mean RI (86%) and mean PI (87%). The repeatability in evaluation of vascular pattern (85%), degree of vascularity (95%) and displacement of vessels (88%) are also high. Results suggest that power Doppler sonography is a reliable method in assessment of the vasculature of cervical lymph nodes.

The use of cross-correlation analysis between high-frequency ultrasound images to measure longitudinal median nerve movement

Impaired nerve movement can lead to nerve injury (e.g., carpal tunnel syndrome). A noninvasive method to measure nerve movement in longitudinal section would enable an extensive analysis of nerve entrapment syndromes. A method has been developed using cross-correlation between successive high-frequency ultrasound (US) images to measure longitudinal movement of nerve and muscle. Control "phantom" experiments demonstrated the accuracy and reliability of this method at velocities of 1-10 mm/s. Increasing the frame interval between the compared frames enabled the accurate calculation of slower velocities. The correlation algorithm successfully measured relative movement when the US transducer was moved 1-3 mm over the surface of the forearm. Median nerve movement was repeatedly measured in the forearm during 30 degrees passive wrist extension in three subjects (range 2.63-4.12 mm) and index finger extension in seven subjects (range 1.59-4.48 mm). Median nerve movement values were consistent with those from cadaver studies.