The pattern of tibial nerve excursion with active ankle dorsiflexion is different in older people with diabetes mellitus

The effectiveness of neurodynamic techniques in patients with diabetic peripheral neuropathy: Study protocol for a randomized sham-controlled trial

Background

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes mellitus (DM). DPN is the primary risk factor for diabetic foot ulcers that can cause amputation. Although several observational studies have investigated the morphological and biomechanical characteristics of peripheral nerves in DPN, interventional studies regarding the effectiveness of neurodynamic techniques (NDT) in DPN patients are confined to a handful. The effects of NDT on neuropathy severity, nerve conduction parameters, quality of life (QoL), and mechanosensitivity have not been explored yet in this population.

Materials and Methods

Forty type 2 DPN (T2DPN) patients, diagnosed based on an electrodiagnosis study, will be recruited into two groups. The experimental group will receive the tibial nerve's real proximal and distal slider techniques in addition to DPN standard treatment as a basic treatment, and the control group will receive the tibial nerve's sham proximal and distal slider techniques along with the basic treatment for eight sessions twice a week. Baseline and post-intervention assessments will be based on the Michigan diabetic neuropathy score (MDNS) (primary outcome), tibial nerve conduction parameters, neuropathy-specific quality of life (Neuro QoL) questionnaire, and straight leg raising range of motion (SLR ROM) (secondary outcomes).

Results

This study is expected to last approximately seven months, depending on recruitment. The results of the study will be published in a peer-reviewed journal.

Conclusions

The present study will evaluate the efficacy of NDT on the primary and secondary outcome measurements in DPN patients.

Longitudinal Movements and Stiffness of Lower Extremity Nerves Measured by Ultrasonography and Ultrasound Elastography in Symptomatic and Asymptomatic Populations: A Systematic Review With Meta-analysis

This study was aimed at analyzing the effectiveness of ultrasonography (US) and ultrasound elastography (UE) in evaluating longitudinal sliding and stiffness of nerves. In line with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, we analyzed 1112 publications (range: 2010-2021) extracted from MEDLINE, Scopus and Web of Science focusing on specific outcomes, including shear wave velocity (m/s), shear modulus (kPa), strain ratio (SR) and excursion (mm). Thirty-three papers were included and evaluated for overall quality and risk of bias. From the analysis of data concerning 1435 participants, mean shear wave velocity (SWV) in the sciatic nerve was 6.70 ± 1.26 m/s in controls and 7.51 ± 1.73 m/s in participants presenting with leg pain; in the tibial nerve, mean SWV was 3.83 ± 0.33 m/s in controls and 3.42 ± 3.53 m/s in participants presenting with diabetic peripheral neuropathy (DPN). The mean shear modulus (SM) was 20.9 ± 9.33 kPa for sciatic nerve, whereas it was an average of 23.3 ± 7.20 kPa for the tibial nerve. Considering 146 subjects (78 experimental, 68 controls) no significant difference was observed in SWV when comparing participants with DPN with controls (standard mean difference [SMD]: 1.26, 95% confidence interval [CI]: 0.54, 1.97), whereas a significant difference was observed in the SM (SMD: 1.78, 95% CI: 1.32, 2.25); furthermore, we found significant differences between left and right extremity nerves (SMD:1.14. 95% CI: 0.45, 1.83) among 458 participants (270 with DPN and 188 controls). No descriptive statistics are available for excursion because of the variability in participants and limb positions, whereas SR is considered only a semiquantitative outcome and therefore not comparable among different studies. Despite the presence of some limitations in study designs and methodological biases, on the basis of our findings, we can conclude that US and UE are effective methods in assessing longitudinal sliding and stiffness of lower extremity nerves in both symptomatic and asymptomatic subjects.

Acute Improvement in Intraoperative EMG During Common Fibular Nerve Decompression in Patients with Symptomatic Diabetic Sensorimotor Peripheral Neuropathy: EMG and Clinical Attribute Interrelations

STUDY AIMS

 Electromyographic (EMG) recordings of the fibularis longus and tibialis anterior muscles were performed intraoperatively during nerve decompression (ND) of the common fibular nerve (CFN) in patients with symptomatic diabetic sensorimotor peripheral neuropathy. Patient demographics and clinical attributes were compared against changes in EMG after ND and analyzed for possible correlations.

METHODS

 Intraoperative changes in CFN EMG were analyzed for correlations against sex, age, body mass index (BMI), hemoglobin A1c (A1c), and type and duration of diabetes.

RESULTS

 Statistically significant changes were found between EMG changes and patient attributes, but no individual correlations were established. Significant EMG improvement was observed for both men and women (p < 0.0001 and p < 0.05, respectively), age groups (4th decade: p < 0.05; 5th decade: p < 0.05; 6th decade: p < 0.01; 7th decade: p < 0.005), diabetes duration (0-9 years: p = 0.002; 10-19 years: p = 0.002; 20-29 years: p = 0.03), and for type 1 and 2 diabetes (type 1: p < 0.005; type 2: p < 0.001). EMG improvement was greater in patients with the highest BMI levels (30-34.9: p = 0.014; 35-39.9: p = 0.013; > 39.9: p = 0.043), and highest A1c levels (> 6.4%; p < 0.0001).

CONCLUSION

 Although long-term clinical studies are needed, these results provide insight into which patients might benefit most from this surgery. These results also suggest that surgical ND can produce an acute improvement in nerve function for both men and women, for people with type 1 and 2 diabetes, and across a wide range of ages, BMI, A1c levels, and disease duration.

Ultrasound measurements of the median nerve at the carpal tunnel in ambulant chronic stroke patients: comparison between paretic and non-paretic sides

[Purpose] The purpose of this study was to examine the cross-sectional area (CSA) and longitudinal sliding length (LSL) of the median nerve bilaterally in patients with ambulant chronic hemiplegia and to compare these measurements with those in healthy controls using ultrasound. [Participants and Methods] Forty patients with hemiplegia who developed a non-functional hand on the paretic side after one year or more of stroke and 25 asymptomatic controls were included. To obtain the CSA of the median nerve at the wrist in the neutral position and the LSL of the median nerve during wrist extension, the participants underwent bilateral ultrasound examination. [Results] The non-paretic side of stroke patients had the largest median nerve CSA, followed by the paretic side and then the controls; the median nerve CSA in the non-paretic side and the controls differed significantly. The CSA of the median nerve was significantly larger in the non-paretic sides of patients, evaluated at more than 5.5 years post-stroke relative to those evaluated at less than 5.5 years. The LSL of the paretic side was significantly shorter than the non-paretic side and the controls. [Conclusion] Compared to the controls, the CSA of the median nerve was enlarged in the non-paretic hand of ambulant chronic stroke patients and the LSL were identical. As such, entrapment neuropathy of the median nerve may follow long-term chronic stroke due to overuse. This study indicates the usefulness of ultrasound in the potential identification of such cases.

Effects of a Multimodal Exercise Program Plus Neural Gliding on Postural Control, Pain, and Flexibility of Institutionalized Older Adults: A Randomized, Parallel, and Double-Blind Study

BACKGROUND AND PURPOSE

The effect of adding neural mobilization to a multimodal program of exercises has not been investigated, despite its potential positive effects. The aim of this study was to compare the acute effects of a multimodal exercise program and neural gliding against a multimodal exercise program only, on pain intensity, gait speed, Timed Up and Go (TUG) test, lower limb flexibility, and static balance of institutionalized older adults.

METHODS

Older adults who were institutionalized (n = 26) were randomized to receive a multimodal exercise program plus neural gliding or a multimodal exercise program only. Both interventions were delivered twice a week for 8 weeks. Participants were assessed for pain, gait velocity, balance, flexibility, and TUG at baseline and postintervention.

RESULTS

A significant main effect of time for pain intensity (F1,24 = 8.95, P = .006), balance (F1,24 = 10.29, P = .004), and gait velocity (F1,24 = 5.51, P = .028) was observed, indicating a positive impact of both interventions. No other significant effects were found (TUG and flexibility; P > .05).

DISCUSSION

A 45-minute multimodal exercise program, twice a week for 8 weeks, has a positive impact on pain intensity, balance, and gait velocity, but neural gliding has no additional benefit. It is unclear whether dose and type of neural mobilization may have had an impact on results. Considering the structural and physiological changes that tend to occur with age, future studies could explore the effects of neural tensioning or of higher doses of neural mobilization.

CONCLUSIONS

This study suggests that adding neural gliding to a multimodal exercise program has no additional benefit.

Acute effects of foam rolling on passive stiffness, stretch sensation and fascial sliding: A randomized controlled trial

PURPOSE

Foam Rolling (FR), aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are poorly understood. The aim of the present study was to further elucidate the acute, systemic and tissue-specific responses evoked by FR.

METHODS

In a crossover study, 16 (34 ± 6y, 6f) participants received all of the following interventions in a random order: a) 2 × 60 seconds of FR at the anterior thigh, b) 2 × 60 seconds of passive static stretching of the anterior thigh (SS), and c) no intervention (CON). Maximal active and passive knee flexion range of motion (ROM), passive stiffness, sliding of fascial layers, as well as knee flexion angle of first subjectively perceived stretch sensation (FSS) were evaluated before and directly after each intervention.

RESULTS

Flexibility increased only after, FR (active (+1.8 ± 1.9%) and passive ROM (+3.4 ± 2.7%), p = .006, respectively) and SS (passive ROM (+3.2 ± 3.5%), p = .002). Angle of FSS was altered following FR (+4.3° (95% CI: 1.4°-7.2°)) and SS (+6.7° (3.7°-9.6°)), while tissue stiffness remained unchanged after any intervention compared to baseline. Movement of the deepest layer (-5.7 mm (-11.3 mm to -0.1 mm)) as well as intrafascial sliding between deep and superficial layer (-4.9 mm (-9.mm to -0.7 mm)) decreased only after FR.

CONCLUSION

FR improved knee flexion ROM without altering passive stiffness, but modified the perception of stretch as well as the mobility of the deep layer of the fascia lata. The mechanisms leading to altered fascial sliding merit further investigation.

Normalization of Spinal Cord Displacement With the Straight Leg Raise and Resolution of Sciatica in Patients With Lumbar Intervertebral Disc Herniation: A 1.5-year Follow-up Study

STUDY DESIGN

A controlled radiologic follow-up study.

OBJECTIVE

The aim of this study was to ascertain whether changes in cord excursion with straight leg raise test (SLR) at 1.5-year follow-up time accompany changes in clinical symptoms.

SUMMARY OF BACKGROUND DATA

Lumbar intervertebral disc herniation (LIDH) is known to be a key cause of sciatica. Previously, we found that a significant limitation of neural displacement (66.6%) was evident with the SLR on the symptomatic side of patients with subacute single level posterolateral LIDH.

METHODS

Fourteen patients with significant sciatic symptoms due to a subacute single-level posterolateral LIDH were reassessed clinically and radiologically at 1.5 years follow-up with a 1.5T MRI scanner. Displacement of the conus medullaris during the unilateral and bilateral SLR was quantified reliably with a randomized procedure and compared between SLRs and to data from baseline. Multivariate regression models and backward variable selection method were employed to identify variables more strongly associated with a decrease in low back pain (LBP) and radicular symptoms.

RESULTS

Compared with previously presented baseline values, the data showed a significant increase in neural sliding in all the quantified maneuvers (P ≤ 0.01), and particularly of 2.52 mm (P ≤ 0.001) with the symptomatic SLR.Increase in neural sliding correlated significantly with decrease of both radicular symptoms (Pearson = -0.719, P ≤ 0.001) and LBP (Pearson = -0.693, P ≤ 0.001). Multivariate regression models and backward variable selection method confirmed the improvement of neural sliding effects (P ≤ 0.004) as the main variable being associated with improvement of self-reported clinical symptoms.

CONCLUSION

To our knowledge, these are the first noninvasive data to objectively support the association between increase in magnitude of neural adaptive movement and resolution of both radicular and LBP symptoms in in vivo and structurally intact human subjects.

LEVEL OF EVIDENCE

2.

Neural gliding and neural tensioning differently impact flexibility, heat and pressure pain thresholds in asymptomatic subjects: A randomized, parallel and double-blind study

OBJECTIVE

To compare the effect of neural gliding and tensioning on hamstring flexibility, nerve function (heat and cold thresholds) and pain sensitivity (pain intensity and pressure pain threshold) of the mobilized and non-mobilized lower limbs at post-intervention and 24 h follow up.

DESIGN

Randomized, parallel and double blinded trial.

SETTING/PARTICIPANTS

Forty-eight asymptomatic participants.

INTERVENTION(S)

Participants received neural gliding (n = 23) or tensioning (n = 25). Main Outcome Measures - Straight leg raising (SLR; in degrees), heat and cold threshold (ºC), pressure pain threshold (PPT; in Kgf) and pain intensity (visual analogue scale), taken at baseline, post-intervention and at 24 h follow up.

RESULTS

There was a significant interaction between time, intervention and limb for SLR (F2,45 = 3.83; p = 0.029). A significant interaction between time and intervention for PPT (F2,45 = 3.59; p = 0.036) and heat threshold (F2,45 = 5.10; p = 0.01). A significant effect of time (F2,45 = 9.42; p < 0.001) and of limb (F1,46 = 4.78; p = 0.035) for pain intensity during SLR, and a significant effect of time (F2,45 = 3.65; p = 0.034) for pain intensity during PPT.

CONCLUSION

Gliding and tensioning had similar and positive effects for flexibility in the mobilized limb, but tensioning was superior for the non-mobilized limb. Gliding was superior to tensioning for pressure pain and heat thresholds.

Noninvasive Measurement of Sciatic Nerve Stiffness in Patients With Chronic Low Back Related Leg Pain Using Shear Wave Elastography

OBJECTIVES

The purpose of this study was to determine whether sciatic nerve stiffness is altered in people with chronic low back-related leg pain by using shear wave elastography.

METHODS

In this cross-sectional study, the sciatic nerve shear wave velocity (ie, an index of stiffness) was measured in both legs of 16 participants (8 with unilateral low back-related leg pain and 8 healthy controls). Sciatic stiffness was measured during a passive ankle dorsiflexion motion performed at 2°/s in an isokinetic dynamometer. The ankle range of motion and passive torque, as well as muscle activity, were also measured.

RESULTS

In people with low back-related leg pain, the affected limb showed higher sciatic nerve stiffness compared to the unaffected limb (+11.3%; P = .05). However, no differences were observed between the unaffected limb of people with low back-related leg pain and the healthy controls (P = .34).

CONCLUSIONS

People with chronic low back-related leg pain have interlimb differences in sciatic nerve stiffness, as measured by a safe and noninvasive method: shear wave elastography. The changes found may be related to alterations in nerve mechanical properties, which should be confirmed by future investigations.

Femoral nerve excursion with knee and neck movements in supine, sitting and side-lying slump: An in vivo study using ultrasound imaging

BACKGROUND

Neurodynamic assessment and management are advocated for femoral nerve pathology. Contrary to neurodynamic techniques for other nerves, there is limited research that quantifies femoral nerve biomechanics.

OBJECTIVES

To quantify longitudinal and transverse excursion of the femoral nerve during knee and neck movements.

DESIGN

Single-group, experimental study, with within-participant comparisons.

METHODS

High-resolution ultrasound recordings of the femoral nerve were made in the proximal thigh/groin region in 30 asymptomatic participants. Scans were made during knee flexion in supine and a semi-seated position, and during neck flexion in side-lying slump (Slump _FEMORAL). Healthy participants were assessed to reveal normal nerve biomechanics, not influenced by pathology. Data were analysed with one-sample and paired t-tests. Reliability was assessed with intraclass correlation coefficients (ICC).

RESULTS

Longitudinal and transverse excursion measurements were reliable (ICC≥0.87). With knee flexion, longitudinal femoral nerve excursion was significant and larger in supine than in sitting (supine (mean (SD)): 3.6 (2.0) mm; p < 0.001; sitting: 1.1 (1.6) mm; p = 0.001; comparison: p = 0.001). There was also excursion in a medial direction (supine: 1.4 (0.3) mm; p < 0.001; sitting: 0.7 (0.6) mm; p < 0.001) and anterior direction (supine: 0.2 (0.2) mm; p < 0.001; sitting: 0.1 (0.2) mm; p = 0.06). Neck flexion in Slump _FEMORAL did not result in longitudinal (0.0 (0.3) mm; p = 0.55) or anteroposterior (0.0 (0.1) mm; p = 0.10) excursion, but resulted in medial excursion (1.1 (0.5) mm; p < 0.001).

CONCLUSION

Although the femoral nerve terminates proximal to the knee, femoral nerve excursion in the proximal thigh occurred with knee flexion; Neck flexion in Slump _FEMORAL resulted in medial excursion.

The potential role of sciatic nerve stiffness in the limitation of maximal ankle range of motion

It is a long held belief that maximal joint range of motion (ROM) is restricted by muscle tension. However, it exists indirect evidence suggesting that this assumption may not hold true for some joint configurations where non-muscular structures, such as the peripheral nerves, are stretched. Direct evidences are lacking. This study aimed to determine whether a static stretching aiming to load the sciatic nerve without stretch within plantar flexors is effective to: (i) alter nerve stiffness; and (ii) increase the ankle’s maximal ROM. Passive maximal ankle ROM in dorsiflexion was assessed with the hip flexed at 90° (HIP-flexed) or neutral (HIP-neutral, 0°). Sciatic nerve stiffness was estimated using shear wave elastography. Sciatic nerve stretching induced both a 13.3 ± 7.9% (P < 0.001) decrease in the nerve stiffness and a 6.4 ± 2.6° increase in the maximal dorsiflexion ROM assessed in HIP-flexed. In addition, the decrease in sciatic nerve stiffness was significantly correlated with the change in maximal ROM in dorsiflexion (r = −0.571, P = 0.026). These effects occurred in the absence of any change in gastrocnemius medialis and biceps femoris stiffness, and ankle passive torque. These results demonstrate that maximal dorsiflexion ROM can be acutely increased by stretching the sciatic nerve, without altering the muscle stiffness.

Ultrasound Elastographic Measurement of Sciatic Nerve Displacement and Shear Strain During Active and Passive Knee Extension

There is current need for objective measures of sciatic nerve mobility in patients with sciatic-type pain. The objective of the study was to assess the feasibility and reliability of ultrasound elastography to quantify sciatic nerve displacement and shear strain at the sciatic nerve-hamstring muscle interface during active and passive knee extension-flexion exercises performed while sitting in healthy people. Ultrasound elastography showed excellent intrarater within-session reliability for assessing sciatic nerve displacement and sciatic nerve-hamstring muscle interface shear strain during active knee extension-flexion exercises. These findings will inform similar future work conducted in patients with sciatic-type pain.

Sciatic nerve stiffness is not changed immediately after a slump neurodynamics technique

Background

Neurodynamics techniques aim to assess and improve neural mechanosensitivity. However, there is no in vivo evidence regarding the mechanical effects of these techniques in the nerve stiffness. This study examined the immediate effects of a slump neurodynamics technique in the sciatic nerve shear wave velocity (SWV. i.e. an index of stiffness) using ultrasound-based elastography.

Methods

Fourteen healthy participants were included in this experiment. Sciatic SWV and ankle passive torque were measured during a passive ankle dorsiflexion motion (2°/s), before and immediately after 3 minutes of slump neurodynamics technique, randomly applied to one lower limb. The contralateral limb served as control.

Results

The slump intervention did not change the sciatic SWV (P=0.78), nor the dorsiflexion passive torque (P=0.14), throughout the ankle dorsiflexion motion. Excellent values of intra-rater repeatability (ICC=0.88, 0.68-0.96), and low values of standard error of measurement (0.59 m/s, 0.35-1.15m/s), were observed for the SWV measurements.

Conclusions

The sciatic nerve stiffness of healthy participants did not change immediately after a slump neurodynamics technique, suggesting a compliance of the neural tissue to tensile loads. However, these results ought to be confirmed using other neurodynamics techniques and in other populations (e.g. peripheral neuropathies).

Level of evidence

III.

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.

Acute effects of foam rolling on passive tissue stiffness and fascial sliding: study protocol for a randomized controlled trial

Background

Self-myofascial release (SMR) aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are still poorly understood. In addition to neuronal mechanisms, improved flexibility may be driven by acute morphological adaptations, such as a reduction in passive tissue stiffness or improved movement between fascial layers. The aim of the intended study is to evaluate the acute effects of SMR on the passive tissue stiffness of the anterior thigh muscles and the sliding properties of the associated fasciae.

Methods

In a crossover study design, 16 participants will receive all of the following interventions in a permutated random order: (1) one session of 2 × 60 s of SMR at the anterior thigh, (2) one session of 2 × 60 s of passive static stretching of the anterior thigh and (3) no intervention. Passive tissue stiffness, connective tissue sliding, angle of first stretch sensation, as well as maximal active and passive knee flexion angle, will be evaluated before and directly after each intervention.

Discussion

The results of the intended study will allow a better understanding of, and provide further evidence on, the local effects of SMR techniques and the underlying mechanisms for flexibility improvements.

Trial registration

ClinicalTrials.gov, identifier: NCT02919527. Registered on 27 September 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1866-y) contains supplementary material, which is available to authorized users.

Safety of lower extremity neurodynamic exercises in adults with diabetes mellitus: a feasibility study

OBJECTIVES

Neurodynamic exercises aim to improve neural mechanosensitivity in order to promote pain-free movement and function. People with diabetes mellitus (DM) may be candidates for neurodynamic exercises to address common DM-related impairments such as reduced lower extremity range of motion (ROM) and altered neural mechanosensitivity. However, no studies have examined the safety and immediate effects of neurodynamic exercise in people with DM. This study aims to determine the feasibility of applying neurodynamic exercises in adults with DM by evaluating the rate of adverse events and quantifying immediate changes in straight leg raise (SLR) ROM.

METHODS

This quasi-experimental study included 20 people with DM who performed a series of neurodynamic exercises on their right leg. Their left leg was used as an internal control. SLR testing was performed before and immediately after these exercises. Adverse events were monitored, including provocation of their neuropathy symptoms or discomfort or pain.

RESULTS

All participants completed the neurodynamic exercises without provocation of their neuropathy symptoms. No pain was reported and only one participant had minor discomfort with one exercise; a <30-s calf cramp. The right SLR ROM increased by an average of 5.2°-5.3° (p < 0.01) with no change on the left.

DISCUSSION

This study demonstrated that lower extremity neurodynamic exercises are safe in adults with DM and may create small immediate improvements in SLR testing. Further research is indicated to investigate the safety and efficacy of neurodynamic exercises performed over multiple sessions.

LEVEL OF EVIDENCE

3b.

Assessing the Reliability of Ultrasound Imaging to Examine Radial Nerve Excursion

Ultrasound imaging allows cost effective in vivo analysis for quantifying peripheral nerve excursion. This study used ultrasound imaging to quantify longitudinal radial nerve excursion during various active and passive wrist movements in healthy participants. Frame-by-frame cross-correlation software allowed calculation of nerve excursion from video sequences. The reliability of ultrasound measurement of longitudinal radial nerve excursion was moderate to high (intraclass correlation coefficient range = 0.63-0.86, standard error of measurement 0.19-0.48). Radial nerve excursion ranged from 0.41 to 4.03 mm induced by wrist flexion and 0.28 to 2.91 mm induced by wrist ulnar deviation. No significant difference was seen in radial nerve excursion during either wrist movement (p > 0.05). Wrist movements performed in forearm supination produced larger overall nerve excursion (1.41 ± 0.32 mm) compared with those performed in forearm pronation (1.06 ± 0.31 mm) (p < 0.01). Real-time ultrasound is a reliable, cost-effective, in vivo method for analysis of radial nerve excursion.

Non-invasive assessment of sciatic nerve stiffness during human ankle motion using ultrasound shear wave elastography

Peripheral nerves are exposed to mechanical stress during movement. However the in vivo mechanical properties of nerves remain largely unexplored. The primary aim of this study was to characterize the effect of passive dorsiflexion on sciatic nerve shear wave velocity (an index of stiffness) when the knee was in 90° flexion (knee 90°) or extended (knee 180°). The secondary aim was to determine the effect of five repeated dorsiflexions on the nerve shear wave velocity. Nine healthy participants were tested. The repeatability of sciatic nerve shear wave velocity was good for both knee 90° and knee 180° (ICCs ≥ 0.92, CVs ≤ 8.1%). The shear wave velocity of the sciatic nerve significantly increased (p<0.0001) during dorsiflexion when the knee was extended (knee 180°), but no changes were observed when the knee was flexed (90°). The shear wave velocity-angle relationship displayed a hysteresis for knee 180°. Although there was a tendency for the nerve shear wave velocity to decrease throughout the repetition of the five ankle dorsiflexions, the level of significance was not reached (p=0.055). These results demonstrate that the sciatic nerve stiffness can be non-invasively assessed during passive movements. In addition, the results highlight the importance of considering both the knee and the ankle position for clinical and biomechanical assessment of the sciatic nerve. This non-invasive technique offers new perspectives to provide new insights into nerve mechanics in both healthy and clinical populations (e.g., specific peripheral neuropathies).

Excursion of the Sciatic Nerve During Nerve Mobilization Exercises: An In Vivo Cross-sectional Study Using Dynamic Ultrasound Imaging

STUDY DESIGN

Controlled laboratory cross-sectional study using single-group, within-subject comparisons.

OBJECTIVES

To determine whether different types of neurodynamic techniques result in differences in longitudinal sciatic nerve excursion.

BACKGROUND

Large differences in nerve biomechanics have been demonstrated for different neurodynamic techniques for the upper limb (median nerve), but recent findings for the sciatic nerve have only revealed small differences in nerve excursion that may not be clinically meaningful.

METHODS

High-resolution ultrasound imaging was used to quantify longitudinal sciatic nerve movement in the thigh of 15 asymptomatic participants during 6 different mobilization techniques for the sciatic nerve involving the hip and knee. Healthy volunteers were selected to demonstrate normal nerve biomechanics and to eliminate potentially confounding variables associated with dysfunction. Repeated-measures analyses of variance were used to analyze the data.

RESULTS

The techniques resulted in markedly different amounts of nerve movement (P<.001). The tensioning technique was associated with the smallest excursion (mean ± SD, 3.2 ± 2.1 mm; P < or = .004). The sliding technique resulted in the largest excursion (mean ± SD, 17.0 ± 5.2 mm; P<.001), which was approximately 5 times larger than that resulting from the tensioning technique and, on average, twice as large as that resulting from individual hip or knee movements.

CONCLUSION

Consistent with current theories and findings for the median nerve, different neurodynamic exercises for the lower limb resulted in markedly different sciatic nerve excursions. Considering the continuity of the nervous system, the movement and position of adjacent joints have a large impact on nerve biomechanics.

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.

Altered tibial nerve biomechanics in patients with diabetes mellitus

INTRODUCTION

Hyperglycemia associated with diabetes mellitus (DM) has adverse impacts on peripheral nerve connective tissue structure, and there is preliminary evidence that nerve biomechanics may be altered.

METHODS

Ultrasound imaging was utilized to quantify the magnitude and timing of tibial nerve excursion during ankle dorsiflexion in patients with DM and matched healthy controls.

RESULTS

Tibial nerve longitudinal excursion at the ankle and knee was reduced, and timing was delayed at the ankle in the DM group. Severity of neuropathy was correlated with larger reductions in longitudinal excursion. Nerve cross-sectional area was increased at the ankle in the DM group.

CONCLUSIONS

Larger tibial nerve size within the tarsal tunnel in patients with DM may restrict longitudinal excursion, which was most evident with more severe neuropathy. It is hypothesized that these alterations may be related to painful symptoms during functional activities that utilize similar physiological motions through various biomechanical and physiological mechanisms.