Upper limb tension tests as tools in the diagnosis of nerve and plexus lesions. Anatomical and biomechanical aspects

Diagnostic accuracy of neurodynamic tests in upper-limb entrapment neuropathies: A systematic review and meta-analysis

BACKGROUND

Upper-limb neurodynamic tests are commonly used to diagnose neuropathies in this area, including cervical radiculopathy and carpal tunnel syndrome, although their diagnostic accuracy remains uncertain across different conditions and criteria.

OBJECTIVE

To assess the diagnostic accuracy of upper-limb neurodynamic tests and their variations and criteria for upper-limb entrapment neuropathies.

METHODS

A systematic review with meta-analysis was conducted in different databases (for their inception in February 2025), including studies evaluating the diagnostic accuracy of these tests. Sensitivity, specificity, likelihood ratios (LR), diagnostic odds ratios, diagnostic accuracy and the area under the curve (AUC) were calculated using a bivariate and univariate meta-analysis. The quality of evidence was evaluated using the GRADE approach, and meta-regression was performed to examine the influence of diagnostic criteria.

RESULTS

Twelve studies were included. Likelihood ratios for neuropathic pain conditions were LR+:1.65 and LR-:0.57, for cervical radiculopathy were LR+:2 and LR-:0.47, and for carpal tunnel syndrome were LR+:1.45 and LR-:0.66. The upper-limb neurodynamic test 2A showed the highest diagnostic accuracy (AUC: 0.76), with LR+:2.59 and LR-:0.42 for cervical radiculopathy, while test 3 had the highest specificity (0.92; LR+:7, LR-:0.48). Diagnostic accuracy for carpal tunnel syndrome was lower (AUC: 0.62). Meta-regression showed significant diagnostic criteria interaction, favoring structural differentiation maneuvers (p = 0.002).

CONCLUSION

Upper-limb neurodynamic tests show moderate sensitivity and low to moderate specificity for diagnosing upper-limb entrapment neuropathies, with diagnostic accuracy varying across conditions. The certainty of evidence ranges from very low to moderate, emphasizing the need for cautious clinical interpretation. Diagnostic reference criteria significantly influence test performance.

Stress and stiffness as predictors of shear wave velocity in peripheral nerve

Shear wave elastography (SWE) is a promising non-invasive indicator for diagnosing peripheral neuropathy. Emerging validation studies using ultrasound-based measures of shear wave velocity (SWV) in other biological tissues, such as muscle, demonstrate there is a concern of whether SWE is an accurate measure of tensile stress or stiffness. Distinguishing between these two parameters and their relationship with SWV is crucial if SWE is to be used as a biomarker for peripheral neuropathies, where changes in mechanical properties are known to occur. In this study, we use cat sciatic nerves to first evaluate SWV in situ at knee positions known to reduce (90° flexion) or increase (180° extension) stress, and then excise nerves to directly quantify the relationships between SWV, stress, and stiffness with ex vivo tensile testing. Our ex vivo findings show that although SWV can be predicted using either stress or stiffness, stress explains more variability in sciatic nerve SWV. However, while stress remains the better predictor of SWV ex vivo, within the SWV range established in situ, stiffness improves its accuracy at estimating SWV, especially when also accounting for factors related to nerve viscoelasticity. Therefore, if SWE is to be used in clinical settings as an indicator of nerve stiffness in peripheral neuropathy, it is essential to standardize parameters such as limb positioning and nerve preloading, which could potentially mask pathological changes in nerve stiffness.

30 second screening test and education reduce chronic pain incidence after blood donation: Large prospective observational study from Japan

Venipuncture is a commonly performed procedure to obtain blood for testing or donation, but nerve injuries with persistent or chronic pain can occasionally occur. We implemented Phalen elbow flexion shoulder abduction (PEFSA) test to screen potential blood donors who may be at risk for persistent or chronic nerve pain after blood donation. Data were prospectively collected on all blood donors at Red Cross centers in Kansai area of Japan for 5 years prior to PEFSA test implementation, and then for 2 years after test implementation. Potential donors who had positive PEFSA test were given a handout informing them of potentially elevated risk for nerve complications. All donors who had persistent pain were followed and treated at Red Cross centers. There were 3,877,975 donors before and 1,461,965 potential donors after PEFSA test implementation. A total of 221 out of 15,776 potential donors with positive PEFSA test decided to stop donation. Prior to test implementation, 98 (0.00253%) donors developed persistent pain. Nineteen had symptoms lasting over 1 year. Six were diagnosed with complex regional pain syndrome (CRPS). After PEFSA test implementation, 22 (0.00151%) developed persistent pain. None had symptoms lasting >1 year or developed CRPS. Our data suggest that the PEFSA test alone do not identify high risk potential donors, but also educating the positive potential donors significantly decrease incidence of persistent pain and CRPS. To our knowledge, this study is the first to test an intervention that can help prevent persistent pain or CRPS from blood donation.

Radiological and biomechanical evaluation of the ulnar nerve after the percutaneous application of the medial K-wire in the extended position on supracondylar humerus fractures: Does the postoperative long arm splint position matter?

Our study aimed to evaluate and compare the changes in ulnar nerve tension and strain at different elbow positions radiologically and mechanically before and after applying the medial K-wire on the supracondylar humerus fracture cadaver model. We used ten fresh frozen cadaver upper extremity specimens to measure strain and tension on the ulnar nerve in 3 different elbow positions: elbow full extension, elbow flexion-forearm supination, and elbow flexion-forearm pronation. We employed Shear wave elastography (Siemens Acuson S3000 USG, 9L4 linear probe) and a microstrain gauge (Microstrain, Inc., Burlington) to obtain our measurements. Minimum, maximum and mean stress and strain values on the nerve and its surroundings were measured and compared statistically. The mean values of elbows with full extension are statistically lower than those in elbows with 90° flexion-forearm supination and those with 90° flexion-forearm pronation positions. Statistical evaluations were performed between all of the groups. Elbow 90° flexion-forearm pronation, both minimum and maximum and mean values were statistically higher in the group, including the specimens with Kirschner applied. The mean values in the elbow full extension and elbow 90° flexion-forearm supination positions were statistically similar in the specimens with and without the K-wire applied. Despite the numerous techniques described in the literature, there is no absolute technical method to prevent ulnar nerve damage. K-wire application to the medial epicondyle with the elbow in a slightly extended position is a technique that can be applied to reduce the risk of ulnar nerve paralysis. However, it has been reported that ulnar nerve damage can be observed in cases where a splint is placed in the 90° flexion position. We hypothesize that the position of the elbow joint in the postoperative period may contribute to ulnar nerve paralysis due to soft tissue tension and strain and as a result of changing the balance of the surrounding tissues. Our findings suggest that the long arm splint applied in elbow 90° flexion and forearm pronation position should not be preferred in the postoperative period. The maximum strain values obtained in the elbow full extension were lower, suggesting that it would be appropriate to stabilize the elbow in the extension position as much as possible postoperatively. Level of evidence: Level V.

A Patient With Pancoast Tumor Presenting With Cervical Radiculopathy: A Case Report

Objective

The purpose of this report was to describe a patient with a Pancoast tumor who presented for chiropractic care with neck and arm pain.

Clinical Features

A 52-year-old male patient with right-sided cervicothoracic pain and numbness in the right upper extremity presented to a chiropractic office for care. The patient reported an occupational history of repetitive lifting motions and overuse injuries. The patient denied history of smoking at the time of presentation.

Intervention and Outcome

Radiographic imaging revealed tracheal deviation. A chest computed tomography image demonstrated a large lesion in the apex of the right lung, suggestive of bronchogenic carcinoma. The patient was referred to an oncology clinic, where he admitted to having a 20-year history of smoking. The diagnosis of adenocarcinoma was made via biopsy, and the oncologist's evaluation confirmed the cancer to be stage IIIC. The patient received palliative care treatments, as the advanced state of his condition determined that he was not a candidate for surgical intervention.

Conclusion

Chiropractors and other first-contact health care providers must keep in mind unusual presentations masquerading as common conditions. This case demonstrates the importance of including apical lung tumors in the differential diagnosis of unilateral arm and neck pain and neurologic deficits of the upper extremity. This case demonstrates the importance of thorough follow-up on images ordered, including the ordering clinicians viewing the images themselves.

Test procedures and positive diagnostic criteria of the upper limb tension tests differ: a systematic review of the DiTA database

BACKGROUND

The validity of the ULTT is unclear, due to heterogeneity of test procedures and variability in the definition of a positive test OBJECTIVE: To evaluate test procedures and positive diagnostic criteria for the upper limb tension test (ULTT) in diagnostic test accuracy studies.

METHODS

A systematic review of diagnostic accuracy studies was performed. We conducted a search of the DiTA (Diagnostic Test Accuracy) database and selected primary studies evaluating the diagnostic accuracy of the ULTT. We assessed risk of bias, performed data extraction on study characteristics, test procedures, and positive diagnostic criteria, and performed a descriptive analysis.

RESULTS

We included nine studies (681 participants), four diagnosing people with cervical radiculopathy (CR), four diagnosing people with carpal tunnel syndrome (CTS), and one included both CR and CTS. The risk of bias varied between 2 and 6 out of 6 positive items. Eight studies reported on the ULTT1 (median nerve). Overall, all studies clearly described their test procedures and positive diagnostic criteria although the order of movements and the diagnostic criteria between studies varied. We suggest a more standardised test procedure for the ULTT1 to consist of: 1) stabilising the shoulder in abduction, 2) extending the wrist/fingers, 3) supinating the forearm, 4) externally rotating the shoulder, 5) extending the elbow, and finally 6) performed structural differentiation by side bending (lateral flexion) of the neck. This proposed test procedure should reproduce the symptoms and enables the clinician to evaluate whether symptoms increase/decrease when stressing or relaxing the nerves.

CONCLUSION

Based on our findings we proposed a more standardised test procedure for the ULTT1 with accompanying positive diagnostic criteria to facilitate homogeneity in future diagnostic accuracy studies of the ULTT.

Upper limb neurodynamic mobilization disperses intraneural fluid in cervical nerve roots: A human cadaveric investigation

BACKGROUND

Cervical radiculopathy is a common cause of neck pain with resultant intraneural edema and impaired nerve function. One strategy to treat radiculopathy is neurodynamic mobilization (NDM); however, little is known about the effect of this treatment on nerve tissue fluid dynamics.

OBJECTIVE

Investigate the impact of upper limb, median nerve-biased NDM on longitudinal intraneural fluid dispersion in the C5,C6,C7 nerve roots in un-embalmed cadavers.

DESIGN

In situ repeated measures.

METHODS

Human cadavers (n = 8) were dissected to expose and inject C5,C6,C7 cervical nerve roots with a dying agent. Initial longitudinal dye spread was recorded after dye spread stabilization. Cadavers were taken through 150 repetitions of upper limb, median nerve-biased NDM followed by dye spread re-measurement. Paired-samples t-tests with Bonferroni correction (α = 0.017) were used to compare pre-vs post-NDM dye spread measurements at C5,C6,C7 nerve roots; a one-way repeated measures ANOVA (α = 0.05) was used to examine differences between change scores for C5,C6,C7 nerve roots.

RESULTS

Median nerve-biased NDM resulted in significant intraneural longitudinal dye spread at C5 and C6 nerve roots of 0.6 ± 0.6 mm and 3.4 ± 3.9 mm, respectively (p < 0.014). Dye spread was not significant at C7 nerve root (0.4 ± 0.7 mm). There was no between root difference in change of longitudinal dye spread between C5, C6, and C7 nerve roots.

CONCLUSIONS

The results of this study show median nerve-biased NDM produced internal fluid movement within C5 and C6 cervical nerve roots. Results provide insight regarding possible mechanism of action and feasibility of NDM in treatment of patients with cervical radiculopathy.

Muscle responses during radial nerve-biased upper limb neurodynamic test in asymptomatic individuals: a cross-sectional study

This laboratory cross-sectional study aimed at explore the muscle response (MR) of the upper trapezius, infraspinatus, biceps brachii and extensor carpi radialis brevis (ECRB) during the radial nerve-biased upper limb neurodynamic test (RN-ULNT) in healthy participants. Myoelectric activity was stage-by-stage recorded during two sequencing variants of the RN-ULNT: S1, in which elbow extension was the last movement; and S2, in which wrist flexion was the last movement. Final elbow and wrist joint angle and sensory response (SR) in five zones (Z1-Z5) were also registered. MR was qualitatively categorized as 'absent' (No-MR), 'true' (TMR) or 'uneven' (UMR). In both sequences, significant increases in muscle activity occurred mostly during shoulder abduction and elbow extension (p ≤ 0.009). Also, elbow extension but not wrist flexion increased the activity of the ECRB muscle (p ≤ 0.009). S2 showed significantly higher upper trapezius (p = 0.04) and biceps brachii (p = 0.036) muscle activity during wrist flexion, and higher report of SR in Z1 and Z4 (p < 0.001) compared to S1. Only the ECRB muscle showed significant differences in the MR type between S1 and S2 (TMR, p = 0.016; UMR, = 0,012). Our results may be useful in the assessment of upper limb musculoskeletal disorders.

Personal influencing factors for pressure pain threshold in healthy people: A systematic review and meta-analysis

All studies that investigated personal factors influencing pressure pain threshold (PPT) in healthy people were synthesized. Data was summarized, and risk of bias (RoB) and level of evidence were determined. Results were pooled per influencing factor, grouped by body region and included in meta-analyses. Fifty-four studies were eligible. Five had low, nine moderate, and 40 high RoB. Following meta-analyses, a strong conclusion was found for the influence of scapular position, a moderate for the influence of gender, and a weak for the influence of age (shoulder/arm region) and blood pressure on PPT. In addition, body mass index, gender (leg region), alcohol consumption and pain vigilance may not influence PPT. Based on qualitative summary, depression and menopause may not influence PPT. For other variables there was only preliminary or conflicting evidence. However, caution is advised, since the majority of included studies showed a high RoB and several were not eligible to include in meta-analyses. Heterogeneity was high in the performed meta-analyses, and most conclusions were weak. More standardized research is necessary.

Comparative effects of tensioning and sliding neural mobilization on peripheral and autonomic nervous system function: A randomized controlled trial

Background

Although different types of neural mobilization (NM) exercises induce different amounts of longitudinal nerve excursion and strain, the question whether the increased longitudinal stress and nerve excursion from sliding or tensioning intervention may subtly affect the neural functions has not been answered yet.

Objective

To compare the effects of tensioning NM versus sliding NM of the median nerve on peripheral and autonomic nervous system function.

Methods

In this randomized controlled trial, 90 participants were randomly assigned to tensioning NM, sliding NM, or sham NM. The neurophysiological outcome measures included peak-to-peak amplitude of the dermatomal somatosensory evoked potential (DSSEP) for dermatomes C6, C7, C8, and T1. Secondary outcome measures included amplitude and latency of skin sympathetic response. All outcome measures were assessed pretreatment, immediately after the two weeks of treatment and one week after the last session of the treatment.

Results

A 2-way repeated measures ANOVA revealed significant differences between the three groups. The post hoc analysis indicated that tensioning NM significantly decreased the dermatomal amplitude for C6, C7, C8, and T1 ( p < 0 . 005 ). Sympathetic skin responses in the gliding NM group showed lower amplitudes and prolonged latencies post-treatment when compared to tensioning NM group ( p < 0 . 05 ). In contrast, no significant changes were observed in the DSSEPs and skin sympathetic responses for participants in the sham treatment group ( p > 0 . 05 ).

Conclusions

A tensioning NM on the median nerve had a possible adverse effect on the neurophysiology variables of the nerves involved in the neural mobilization. Thus, tensioning NM with the current parameters that place increased stress and strain on the peripheral nervous system should be avoided.

Assessing the Effects of Scapular Positioning on the Morphology of the Median Nerve During Upper Limb Tension Test 1 (ULTT1)

Objective:

The upper limb tension test 1 (ULTT1) is commonly used by physical therapists for patients with complaints of radiating symptoms in their upper extremity following the path of the median nerve. Clinicians typically perform similar testing positions for patients, except for scapular position, which may vary between scapular blocking and scapular depression. This may alter the test results based on this positioning. The purpose of this study was to determine if there is a significant difference in median nerve morphology during the ULTT1 between resting and two scapular testing positions.

Materials and Methods:

Thirty healthy participants, 18 to 65 years of age, were tested using the ULTT1 in both blocked and depressed scapular positions. The height and width of the median nerve were measured by diagnostic sonography. Paired t tests were utilized to compare baseline, blocked, and depressed scapular positions with the ULTT1.

Results:

No statistically significant difference in height or width was found between resting, blocked, or depressed scapular positioning.

Conclusion:

There were inconclusive results regarding the morphology of the median nerve in this study.

Key Takeaways

Inconclusive results on nerve morphology comparing two scapular positions during the ULTT1. Research may be conducted on symptomatic patients to assist with more reliable test findings related to ULTT1.

Neurodynamic Functions and Their Correlations with Postural Parameters in Adolescents with Idiopathic Scoliosis

Knowledge about neurodynamic functions of the nervous system (NS) in patients with idiopathic scoliosis (IS) is limited. This study aimed to assess the mechanosensitivity of the NS structures (MNS) in adolescents with IS. The study included 69 adolescents with IS and 57 healthy peers aged 10–15 years. The Upper Limb Neurodynamic Test 1 (ULNT1), straight leg raise (SLR) test, and slump test (SLUMP) were used to assess MNS. The spinal curvatures in the sagittal plane and selected ranges of motion were measured. The data were analysed using the Mann–Whitney U test and Spearman’s rank correlation. Increased MNS assessed by ULNT1 and SLUMP tests was observed in participants with IS. Values of the neurodynamic tests correlated significantly with the sagittal profile of the spine and the mobility of the spine and lower limbs in both groups. In conclusion, increased MNS occurs in adolescents with IS. Therefore, the examination of adolescents with IS should include an assessment of MNS with the neurodynamic tests. Future studies should investigate this issue to better understand the mechanisms that coexist with IS.

Deep Learning Approaches to Automated Video Classification of Upper Limb Tension Test

The purpose of this study was to classify ULTT videos through transfer learning with pre-trained deep learning models and compare the performance of the models. We conducted transfer learning by combining a pre-trained convolution neural network (CNN) model into a Python-produced deep learning process. Videos were processed on YouTube and 103,116 frames converted from video clips were analyzed. In the modeling implementation, the process of importing the required modules, performing the necessary data preprocessing for training, defining the model, compiling, model creation, and model fit were applied in sequence. Comparative models were Xception, InceptionV3, DenseNet201, NASNetMobile, DenseNet121, VGG16, VGG19, and ResNet101, and fine tuning was performed. They were trained in a high-performance computing environment, and validation and loss were measured as comparative indicators of performance. Relatively low validation loss and high validation accuracy were obtained from Xception, InceptionV3, and DenseNet201 models, which is evaluated as an excellent model compared with other models. On the other hand, from VGG16, VGG19, and ResNet101, relatively high validation loss and low validation accuracy were obtained compared with other models. There was a narrow range of difference between the validation accuracy and the validation loss of the Xception, InceptionV3, and DensNet201 models. This study suggests that training applied with transfer learning can classify ULTT videos, and that there is a difference in performance between models.

Immediate effects of rhythmic joint mobilization of the temporomandibular joint on pain, mouth opening and electromyographic activity in patients with temporomandibular disorders

BACKGROUND

Rhythmic joint mobilizations (RJM) of the temporomandibular joint (TMJ) are employed to relieve pain and improve function in patients with temporomandibular disorders (TMD). However, the evidence on the immediate effects of RJM in patients with TMD is scarce. The aim of this study was to assess the immediate clinical and functional effects of RJM in patients with TMD.

MATERIALS AND METHODS

This was a one-group quasi-experimental before and after study. Thirty-eight patients with TMD were assessed by means of pain intensity (visual analogue score, VAS), pressure pain threshold (PPT, measured through pressure algometry on the masseter and temporal muscles), mouth opening (MO, measured with a ruler), and surface electromyographic activity of the masseter and temporal muscles (asymmetry index, AI). Measurements were performed before and after a single, 1-min session of RJM of each TMJ. All statistical analyses were performed using the SPSS version 20.0 statistical package.

RESULTS

A statistical significant difference was found in pain intensity, PPT and MO after the intervention (p < 0.05). No difference was found in the AI. A large effect size was observed for pain intensity, PPT of the left and right masseter muscles and MO (d = 0.85-1.13), whereas for the left and right temporal muscles the effect size was moderate (d = 0.62) and small, respectively (d = 0.49).

CONCLUSION

In this sample of patients with TMD, a single session of RJM of the TMJ seemed to be effective in reducing pain intensity, increasing PPT and improving MO immediately after the intervention, without differences in the AI.

Evaluation and Management of Neurogenic Thoracic Outlet Syndrome with an Overview of Surgical Approaches: A Comprehensive Review

Neurogenic thoracic outlet syndrome (NTOS) represents a disorder believed to involve compression of one or more neurovascular elements as they exit the thoracic outlet. This comprehensive literature review will focus on the occurrence, classification, etiology, clinical presentation, diagnostic measures, and both nonoperative and operative therapies for NTOS. NTOS represents the most common subtype of thoracic outlet syndrome and can significantly impair quality of life. Botulinum toxin injection into the anterior scalene muscle, or even the middle scalene or pectoralis minor muscles, can reduce the symptoms of this syndrome. The best available evidence for botulinum toxin therapy to the cervicothoracic muscles supports the value of this treatment for reducing pain in the affected extremity, and for an approximate duration of 2 months or more. Surgical approaches and newer minimally invasive surgical approaches offer high rates of improvement in select centers.

Ulnar Nerve Dislocation and Subluxation from the Cubital Tunnel Are Common in College Athletes

Background: Hypermobility of the ulnar nerve from the cubital tunnel reportedly occurs in healthy people without symptoms of ulnar neuropathy. However, the occurrence rate in athletes is unknown. We examined the occurrence rate of ulnar nerve hypermobility using ultrasonography, symptoms, and physical findings in athletes and compared the results of four types of sports. Methods: Medical charts of college athletes competing in baseball, rugby, soccer, and long-distance running between March and November 2018 were retrospectively examined. Dynamic evaluation of the ulnar nerve was performed using ultrasonography and categorized as Types N, S, and D respectively, indicating normal position, subluxation, and dislocation. Subjective and objective findings were evaluated. Results: The present study included 246 male athletes (mean age, 19.7 years; 492 elbows) including 46% Type D, 29.8% Type S, and 24.2% Type N. Subjective findings showed pain and dysesthesia in 9% and 4.5% of participants, respectively, whereas objective findings showed Tinel sign in 6%, nerve tension test in 1.3%, Froment’s sign in 0.5%, and weakness of strength of opponens digiti minimi muscle in 8% of patients with Types D and S. Conclusions: There was a high-frequency hypermobility of the ulnar nerve from the cubital tunnel with or without subjective and objective findings in college athletes.

Supernumerary Head of the Biceps Brachii Muscle: An Anatomic Variant With Clinical Implications

Objective

The purpose of this anatomic case report is to describe a variation of the biceps brachii muscle identified in an adult male cadaveric specimen and its potential clinical relevance.

Methods

A cadaveric specimen with a left supernumerary biceps brachii muscle was dissected. Adjacent neurovascular structures were isolated, and their pathways were observed for possible areas of compression.

Results

A tricipital supernumerary head of the biceps brachii muscle was noted on the left upper extremity in an embalmed human cadaveric specimen. The median nerve and brachial artery maintained their common neurovascular path. The musculocutaneous nerve passed deep to the third head of the anatomic variant before distributing its cutaneous branches as the lateral antebrachial cutaneous nerve.

Conclusion

The presence of a supernumerary biceps brachii muscle may cause neurovascular compression of the median nerve, musculocutaneous nerve, or brachial artery, resulting in peripheral nerve deficits. When patient conditions are refractory to care, they may warrant careful evaluation of the anterior compartment of the arm for potential anomalous muscle variations.

Upper limb neurodynamic testing with radial and ulnar nerve biases: An analysis of cervical spinal nerve mechanics

BACKGROUND

Clinical research supports a combination of upper limb neurodynamic testing (ULNT) strategies to rule out upper limb and cervical neurogenic pathology; however, knowledge of the biomechanical response of spinal nerves during ULNT is lacking for radial and ulnar nerve biases.

OBJECTIVE

To assess whether radial and ulnar nerve biased strategies of ULNT elicit significant displacement and strain of cervical spinal nerves.

STUDY DESIGN

Cross-sectional.

METHODS

Radiolucent markers were implanted into spinal nerves C5-C8 proximal and distal to the intervertebral foramen in nine unembalmed cadavers (six male; three female) age 80.1 ± 13.2 years. Fluoroscopic images were captured during ULNT with radial and ulnar nerve biases. Images at rest and maximum tension were digitized and displacement and strain were measured. All data were analyzed using one sample t-tests and a generalized linear mixed models approach.

RESULTS

Upper limb neurodynamic testing with radial nerve bias resulted in displacement (2.44-3.04 mm) and strain (7.99-11.98%) and ULNT with ulnar nerve bias resulted in displacement (2.16-4.41 mm) and strain (7.12 and 12.95%). Significant extraforaminal displacement occurred during radial and ulnar nerve biases for all spinal nerves (all P < 0.05) whereas significant strain occurred during ulnar nerve biases for all spinal nerves but only in C6-C8 during radial nerve bias.

CONCLUSION

Upper limb neurodynamic testing using both radial and ulnar nerve biases resulted in cervical spinal nerve displacement and strain. Such techniques could be used to tension load or mobilize or cervical spinal nerves to evaluate for pathology.

Reducing the Risk and Impact of Brachial Plexus Injury Sustained From Prone Positioning-A Clinical Commentary

INTRODUCTION

Prone positioning is deployed as a critical treatment for improving oxygenation in patients with Acute Respiratory Distress Syndrome. This regimen is currently highly prevalent in the COVID-19 pandemic. The pandemic has brought about increased concern about how best to safely avoid brachial plexus injuries when caring for unconscious proned patients.

METHODS

A review of the published literature on brachial plexus injuries secondary to proning ventilated patients was performed. This was combined with a review of available international critical care guidelines in order to produce a succinct set of guidelines to aid critical care departments in reducing brachial plexus injuries during these challenging times.

DISCUSSION

There is no one manner in which prone positioning an unconscious patient can be made universally safe. This paper provides 6 key steps to reducing the incidence of brachial plexus injuries while proning and suggests a safe and sensible management and referral pathway for the conscious patient in which a brachial plexus injury is identified.

CONCLUSION

There is in truth no completely safe position for every patient and certainly there will be anomalies in anatomy that will predispose certain individuals to nerve injury. Thus the injury rate cannot be reduced to zero but an understanding of the principles of protection will inform those undertaking positioning.

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.

Reliability and accuracy of the brachial plexus neurodynamic test

STUDY DESIGN

Observational study.

INTRODUCTION

The brachial plexus neurodynamic test (BPNT), based on previous neurodynamic tests, is considered a clinically meaningful tool to objectively assess brachial plexus extensibility. This novel test's psychometric properties have yet to be determined.

PURPOSE OF THE STUDY

The primary study aim was to assess the inter- and intrarater reliability and accuracy of the BPNT, which biases the median nerve and brachial plexus, among clinicians of various professional experience levels and geographic US regions. The secondary study aim was to determine if professional experience or geographic region affects the accuracy levels of this test.

METHODS

In phase 1, inter-rater reliability and accuracy was determined. About 307 participants attending neural mobilization conferences and courses were instructed in the BPNT and asked to score 7 different videos of 14 possible test levels. In phase 2, intrarater reliability was determined via scoring the same test videos twice.

RESULTS

High inter-rater intraclass correlation coefficient (range, 0.98-0.99) and accuracy (range, 0.88-0.94) levels were determined for all clinical experience levels and geographic regions. Intrarater intraclass correlation coefficient values were high (range, 0.96-1.0) among all participants. One-way analysis of variance indicated no significant differences on test accuracy based on professional clinical experience (F = 0.104; P = .958) and geographic region (F = 0.416; P = .416) among all 307 participants.

DISCUSSION

Excellent inter- and intrarater reliability and accuracy levels may allow clinicians to correctly identify BPNT positions regardless of their professional experience or geographic location.

CONCLUSION

The BPNT can reliably and accurately quantify outcomes in neural mobility scoring.

Median Neuropathy After Blood Draw Mimics Painful Clenched Fist Syndrome in a Child

Background: Clenched fist syndrome is a rare disorder, often attributed to a conversion disorder without anatomic basis. Here, we review the literature surrounding clenched fist syndrome and challenge the assumption it is always psychiatric in origin, via description of a case of clenched fist syndrome responsive to surgical nerve decompression. Methods: An unusual case of clenched fist syndrome is reviewed and discussed. Results: A child presenting with clenched fist syndrome failed conservative measures consisting of formal hand therapy, multidisciplinary pain management, and psychiatric treatment. On clinical examination, she had findings consistent with median nerve entrapment. After undergoing surgical decompression of the median nerve in the forearm and carpal tunnel, the clenched fist resolved immediately. Conclusions: Nerve compression may be an unrecognized factor underlying some cases of clenched fist syndrome. Evaluation by a hand surgeon or a hand therapist skilled in the detection of peripheral nerve entrapment or injury should be considered as part of the workup for this rare disorder.

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder regions, collectively referred to as the brachial plexus (BP). Despite recent advances in obstetrical care, the problem of NBPP continues to be a global health burden with an incidence of 1.5 cases per 1,000 live births. More severe types of this injury can cause permanent paralysis of the arm from the shoulder down. Prevention and treatment of NBPP warrants an understanding of the biomechanical and physiological responses of newborn BP nerves when subjected to stretch. Current knowledge of the newborn BP is extrapolated from adult animal or cadaveric BP tissue instead of in vivo neonatal BP tissue. This study describes an in vivo mechanical testing device and procedure to conduct in vivo biomechanical testing in neonatal piglets. The device consists of a clamp, actuator, load cell, and camera system that apply and monitor in vivo strains and loads until failure. The camera system also allows monitoring of the failure location during rupture. Overall, the presented method allows for a detailed biomechanical characterization of neonatal BP when subjected to stretch.

Upper limb neurodynamic test 1 in patients with clinical diagnosis of carpal tunnel syndrome: A diagnostic accuracy study

STUDY DESIGN

Diagnostic accuracy.

INTRODUCTION

Upper limb neurodynamic test 1 (ULNT1) is used to evaluate the mechanical sensitivity especially in the peripheral nerves of the upper limbs. The reproduction of typical symptoms in the affected hand improves the estimation of the probability of carpal tunnel syndrome (CTS). However the test has not been evaluated sufficiently to determine its real usefulness. In the present study the diagnostic accuracy of ULNT1 as a clinical test for CTS was determined.

METHODS

We used the ULNT1 as the index test and nerve conduction as the reference standard. 120 subjects, (240 hands), with a medical diagnosis of CTS were evaluated. The study population was a consecutive series of participants. Sensitivity, specificity, positive and negative predictive values, accuracy, and positive likelihood ratio were calculated.

RESULTS

ULNT1 was found to have a sensitivity of 93 % and a specificity of 6.67 %. The positive likelihood ratio was 1.04 and the negative likelihood ratio was 1.00. The positive predictive value was 86.9 % and the negative predictive value was 12.5%.

DISCUSSION

Acute or relatively mild CTS cases may not be accurately identified through nerve conduction tests. The findings of this study coincide with other studies in the finding that ULNT1 has a significant diagnostic and clinical screening value for CTS in people at-risk, or with upper limb symptoms.

CONCLUSION(S)

This research suggests the use of ULNT1 as a screening test for CTS, followed by tests that are more specific.

LEVEL OF EVIDENCE

III-2.

A force-measuring and behaviour-recording system consisting of 24 individual 3D force plates for the study of single limb forces in climbing animals on a quasi-cylindrical tower

This study describes the design of a new force measuring array with a quasi-cylindrical surface for measuring the 3D ground reaction forces of animals climbing on a surface with high curvature. This force-measuring array was assembled from 24 individual 3D force sensors, each with a resolution at the millinewton (mN) level, which were installed from top to bottom in four columns and six rows, with sensors in neighbouring columns staggered in height. Three cameras were used to simultaneously record the climbing behaviours of animals (in these experiments tree frogs) on the cylinder-like force measuring array. We were thus able to simultaneously record the ground reaction forces of each of the four limbs of tree frogs (here six individuals of the Chinese gliding or flying frog, Rhacophorus dennysi, with forelimb spans in the range 163-201 mm) climbing or descending both smooth and rough surfaces on a quasi-cylindrical structure with an overall diameter of 79 mm. We describe the design and calibration of the individual force sensors, their installation and arrangement on the quasi-cylindrical climbing tower, the recording of ground reaction forces and climbing behaviour, data transformations necessitated by the angular relationship of neighbouring sensors, and data processing using MATLAB scripts. Additionally, we present preliminary data on the use of a clamping grip by climbing frogs and the existence of small pull-off forces that aid toe-pad detachment at the end of each locomotor stance phase.

Biomechanical Responses of Neonatal Brachial Plexus to Mechanical Stretch

This study investigated the biomechanical responses of neonatal piglet brachial plexus (BP) segments—root/trunk, chord, and nerve at two different rates, 0.01 mm/second (quasistatic) and 10 mm/second (dynamic)—and compared their response to another peripheral nerve (tibial). Comparisons of mechanical responses at two different rates reported a significantly higher maximum load, maximum stress, and Young's modulus (E) values when subjected to dynamic rate. Among various BP segments, maximum stress was significantly higher in the nerve segments, followed by chord and then the root/trunk segments except no differences between chord and root/trunk segments at quasistatic rate. E values exhibited similar behavior except no differences between the chord and root/trunk segments at both rates and no differences between chord and nerve segments at quasistatic rate. No differences were observed in the strain values. When compared with the tibial nerve, only mechanical properties of BP nerves were similar to the tibial nerve. Mechanical stresses and E values reported in BP root/trunk and chord segments were significantly lower than tibial nerve at both rates. When comparing the failure pattern, at quasistatic rate, necking was observed at maximum load, before a complete rupture occurred. At dynamic rate, partial rupture at maximum load, followed by a full rupture, was observed. Occurrence of the rate-dependent failure phenomenon was highest in the root/trunk segments followed by chord and nerve segments. Differences in the maximum stress, E values, and failure pattern of BP segments confirm variability in their anatomical structure and warrant future histological studies to better understand their stretch responses.

Evidence for Increased Magnetic Resonance Imaging Signal Intensity and Morphological Changes in the Brachial Plexus and Median Nerves of Patients With Chronic Arm and Neck Pain Following Whiplash Injury

Background Whiplash following a motor vehicle accident can result in chronic neck and arm pain. Patients frequently present with cutaneous hypersensitivities and hypoesthesia, but without obvious clinical signs of nerve injury. T2-weighted magnetic resonance imaging (MRI) has previously been used to identify nerve pathology. Objectives To determine whether there are signs of peripheral nerve pathology on MRI in patients with chronic arm and neck pain following whiplash injury. Methods This cross-sectional study used T2-weighted MRI to examine the brachial plexus and median nerve in patients and age-matched, healthy control subjects. Clinical examination included tests of plexus and nerve trunk mechanical sensitivity. Results The T2 signal intensity was greater in the brachial plexus and median nerve at the wrist in the patient group (mean intensity ratio = 0.52 ± 0.13 and 2.09 ± 0.33, respectively) compared to the control group (mean intensity ratio = 0.45 ± 0.07 and 1.38 ± 0.31, respectively; P<.05). Changes in median nerve morphology were also observed, which included an enlargement (mean area: patient group, 8.05 ± 1.29 mm²; control group, 6.52 ± 1.08 mm²; P<.05) and flattening (mean aspect ratio: patient group, 2.46 ± 0.53; control group, 1.62 ± 0.30; P<.05) at the proximal carpal row. All patients demonstrated signs of nerve trunk mechanical sensitivity. Conclusion These findings suggest that patients with chronic whiplash may have inflammatory changes and/or mild neuropathy, which may contribute to symptoms. J Orthop Sports Phys Ther 2018;48(7):523-532. Epub 24 Apr 2018. doi:10.2519/jospt.2018.7875.

Comparison of Median Nerve Mechanosensitivity and Pressure Pain Threshold in Patients With Nonspecific Neck Pain and Asymptomatic Individuals

OBJECTIVE

The purpose of this study was to investigate the presence of median nerve mechanosensitivity by comparing median nerve neurodynamic test results of patients with nonspecific neck pain (NNP) and asymptomatic individuals.

METHODS

A total of 40 patients (30 women, 10 men) with NNP between the ages of 21 and 62 years (39.53 ± 10.18 years) and 38 asymptomatic individuals (23 women, 15 men) between the ages of 18 and 60 years (37.13 ± 9.64 years) participated in the study. Pressure pain threshold was assessed with digital pressure algometer, cervical joint range of motion was assessed with a universal goniometer, and median nerve mechanosensitivity was assessed with Upper Limb Neurodynamic Test 1 (ULNT1). The test step where the first sensory response was given, the location and character of the sensory response, and the final elbow extension angle were recorded during ULNT1.

RESULTS

Patients with NNP had significantly decreased pressure pain threshold (P < .001), decreased range of motion of cervical flexion (P < .001), and decreased cervical lateral flexion (P = .001) compared with asymptomatic individuals, whereas no change was identified in range of motion of rotation (P = .100). In ULNT1, 45% of patients with NNP reported pain and 40% of them reported stretch. A total of 65% of asymptomatic individuals reported stretch, and 13% of them reported pain. It was identified in ULNT1 that final elbow extension angle was lower in the NNP group compared with asymptomatic individuals (P = .008).

CONCLUSION

Median nerve mechanosensitivity increased, pressure pain threshold decreased, and active neck motion was limited in individuals with NNP compared with asymptomatic individuals.

Improvement of severe myalgic encephalomyelitis/chronic fatigue syndrome symptoms following surgical treatment of cervical spinal stenosis

Background

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a potentially disabling disorder. Little is known about the contributors to severe forms of the illness. We describe three consecutive patients with severe ME/CFS whose symptoms improved after recognition and surgical management of their cervical spinal stenosis.

Methods

All patients satisfied clinical criteria for ME/CFS and orthostatic intolerance, and were later found to have cervical spinal stenosis. Overall function was assessed before and after surgery using the Karnofsky score and the SF-36 physical function subscale score.

Results

Neurological findings included > 3+ deep tendon reflexes in 2 of 3, a positive Hoffman sign in 2 of 3, tremor in 2 of 3, and absent gag reflex in 1 of 3. The cervical spine canal diameter in the three patients ranged from 6 to 8.5 mm. One had congenital cervical stenosis with superimposed spondylosis, and two had single- or two-level spondylosis. Anterior cervical disc replacement surgery in two patients and a hybrid anterior cervical disc fusion and disc replacement in the third was associated with a marked improvement in myelopathic symptoms, resolution of lightheadedness and hemodynamic dysfunction, improvement in activity levels, and improvement in global ME/CFS symptoms.

Conclusions

The prompt post-surgical restoration of more normal function suggests that cervical spine stenosis contributed to the pathogenesis of refractory ME/CFS and orthostatic symptoms. The improvements following surgery emphasize the importance of a careful search for myelopathic examination findings in those with ME/CFS, especially when individuals with severe impairment are not responding to treatment.

The influence of a depressed scapular alignment on upper limb neural tissue mechanosensitivity and local pressure pain sensitivity

BACKGROUND

A depressed scapular alignment could lead to prolonged and repetitive stress or compression of the brachial plexus, resulting in sensitization of neural tissue. However, no study has investigated the influence of alignment of the scapulae on sensitization of upper limb neural tissue in otherwise asymptomatic people. In this case-control study, we investigate the influence of a depressed scapular alignment on mechanosensitivity of the upper limb peripheral nervous system as well as pressure pain thresholds (PPT).

METHODS

Asymptomatic individuals with neutral vertical scapular alignment (n = 25) or depressed scapular alignment (n = 25) participated. We measured the upper limb neurodynamic test (ULNT1), including assessment of symptom response and elbow range of motion (ROM), and PPT measured over upper limb peripheral nerve trunks, the upper trapezius muscle and overlying cervical zygapophyseal joints.

RESULTS

Subjects with a depressed scapular reported significantly greater pain intensity (t = 5.7, p < 0.0001) and reduced elbow extension ROM (t = -2.7, p < 0.01) during the ULNT1 compared to those with a normal scapular orientation. Regardless of the location tested, the group presenting with a depressed scapular had significantly lower PPT compared to those with a normal scapular orientation (PPT averaged across all sites: normal orientation: 3.3 ± 0.6 kg/cm², depressed scapular: 2.1 ± 0.5 kg/cm², p < 0.00001).

CONCLUSIONS

Despite being asymptomatic, people with a depressed scapular have greater neck and upper limb neural tissue mechanosensitivity when compared to people with a normal scapular orientation. This study offers insight into the potential development of neck-arm pain due to a depressed scapular position.

Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome

Thoracic outlet syndrome (TOS) is a group of disorders all having in common compression at the thoracic outlet. Three structures are at risk: the brachial plexus, the subclavian vein, and the subclavian artery, producing neurogenic (NTOS), venous (VTOS), and arterial (ATOS) thoracic outlet syndromes, respectively. Each of these three are separate entities, though they can coexist and possibly overlap. The treatment of NTOS, in particular, has been hampered by lack of data, which in turn is the result of inconsistent definitions and diagnosis, uncertainty with regard to treatment options, and lack of consistent outcome measures. The Committee has defined NTOS as being present when three of the following four criteria are present: signs and symptoms of pathology occurring at the thoracic outlet (pain and/or tenderness), signs and symptoms of nerve compression (distal neurologic changes, often worse with arms overhead or dangling), absence of other pathology potentially explaining the symptoms, and a positive response to a properly performed scalene muscle test injection. Reporting standards for workup, treatment, and assessment of results are presented, as are reporting standards for all phases of VTOS and ATOS. The overall goal is to produce consistency in diagnosis, description of treatment, and assessment of results, in turn then allowing more valuable data to be presented.

Differences in Neural Mechanosensitivity Between Patients with Chronic Nonspecific Neck Pain With and Without Neuropathic Features. A Descriptive Cross-Sectional Study

OBJECTIVE

To assess differences in neural mechanosensitivity between patients with chronic nonspecific neck pain with and without neuropathic features (NF and No-NF, respectively).

DESIGN

Descriptive, cross-sectional study.

SETTING

A primary care center, a hospital physiotherapy outpatient department, and a university campus.

SUBJECTS

Chronic nonspecific neck pain patients classified by the self-completed leeds assessment of neuropathic symptoms and signs pain scale (S-LANSS; 49 patients with NF [S-LANSS ≥ 12] and 50 patients with No-NF [S-LANSS < 12]) and a healthy control group (n = 48).

METHODS

The primary measurements were the mechanosensitivity of the median nerve and cervical region, specifically the assessment of the onset of symptoms and submaximal pain intensity according to the upper limb neural test 1 (ULNT1) for the median nerve and the modified passive neck flexion test (MPNFT) for the cervical region; secondary measurements included pain intensity, neck disability, kinesiophobia, and pain catastrophizing.

RESULTS

Statistically significant differences between the NF and No-NF groups were found with respect to the onset of symptoms of ULNT1 (-15.11 [-23.19 to -7.03]) and MPNFT (-6.58 [-11.54 to -1.62]), as well as the outcomes of the visual analogue scale (Mean difference [95% Confidence Interval]; 7.12 [1.81-12.42]) and neck disability index (3.72 [1.72-5.71]). Both chronic nonspecific neck pain groups showed statistically significant differences compared with the control group for all outcomes assessed (P < 0.01) except for the onset of symptoms of ULNT1 in the No-NF group.

CONCLUSIONS

The findings of this study suggest that chronic nonspecific neck pain patients with NF have greater neural mechanosensitivity, pain intensity, and neck disability than those with No-NF.

Upper Limb Neurodynamic Test 1 on Healthy Individuals: Intra- and Intersession Reliability of the Angle between Pain Onset and Submaximal Pain

Assessment of nerve trunk mechanosensitivity using the upper limb neurodynamic test 1 (ULNT1) often includes measurement of the angle of occurrence in the range of pain onset (PO) and submaximal pain (SP). A measurement that better fits the idea of mechanosensitivity could be the angle between PO and SP (AbOS). This study investigated the intra- and intersession reliability of AbOS, PO, and SP during the ULNT1. Forty-four healthy volunteers underwent three ULNT1 to the point of PO and SP, twice in the first session and once in the second. AbOS, PO, and SP angles of occurrence reliability were examined using the Intraclass Correlation Coefficient (ICC 3,1) and Bland-Altman plots. The intra- and intersession ICC values for AbOS were 0.71 (95% CI: 0.47; 0.85) and 0.79 (95% CI: 0.60; 0.89), respectively. The intra- and intersession mean difference and 95% limits of agreement (±1.96 SD) in the Bland-Altman plots were 2.3° (-18.3°; 23.1°) and 2.8° (-14.7°; 20.4°), respectively. The intra- and intersession reliability of the AbOS during the ULNT1 in healthy individuals is high and higher than the reliability of PO and SP angles of occurrence. The AbOS could be a preferable variable in the assessment of neural mechanosensitivity.

Impact of shoulder internal rotation on ulnar nerve excursion and strain in embalmed cadavers. A pilot study

DESIGN

Laboratory study, repeated-measures design.

OBJECTIVE

To determine if the substitution of shoulder internal rotation for external rotation during the upper limb neurodynamic test (ULNT3) evokes a comparable ulnar nerve excursion and strain in embalmed cadavers. Shoulder external rotation is a primary movement component of the ULNT3. It has been suggested that shoulder internal rotation may provide a similar load to the nervous system. There are no data to either support or negate this claim.

METHODS

Excursion and strain were measured in the ulnar nerve of six embalmed cadavers during the traditional ULNT3 and an experimental maneuver using shoulder internal rotation.

RESULTS

The total means±SD of excursion for the traditional and experimental maneuvers were 2·11±0·89 and 2·09±0·92 mm, respectively. The total means±SD of strain for the traditional and experimental maneuvers were 5·274±2·223 and 5·241±2·308%, respectively. A very strong correlation (r = 0·98) was shown to exist between maneuvers and this relationship was determined to be significant (P = 0·001).

DISCUSSION

The results of this study provide evidence that there is no appreciable difference in excursion or strain when substituting shoulder internal rotation for external rotation during the ULNT3. Patients who exhibit limitation of shoulder external rotation mobility may benefit from this substitution when presenting with signs of ulnar nerve pathodynamics. Further research involving patients will be needed to assess the validity of the experimental maneuver for clinical application.

Determination of the longitudinal median nerve mobility in different neurodynamic techniques

Background

Neurodynamic techniques which include tensioning and gliding techniques are being employed in the treatment of carpal tunnel syndrome. There are few in vivo studies that have assessed the longitudinal mobility of the nerve using these techniques. The objective of this study was to determine the longitudinal excursion of the median nerve at the level of the wrist and distal arm by having the cervical spine lateral flexion or the wrist extension as terminal movement.

Method

Twenty healthy participants were included in the study. Techniques 1 and 2 had wrist extension as its terminal movement while techniques 3 and 4 had ipsilateral and contralateral neck lateral flexion as its terminal motion. Median nerve longitudinal excursion was determined using dynamic ultrasound and was measured by a motion tracking analysis program employing a fast template tracking method.

Results

Regardless of neurodynamic techniques, longitudinal mobility is highest at the wrist and arm level if the terminal movement is wrist extension. Median nerve excursion at the wrist and arm levels is 15.53 ± 7.04 mm and 6.82 ± 2.97 mm for technique 1 and 13.43 ± 5.64 and 5.33 ± 2.37 mm for technique 2, respectively. There was a significant decrease in median nerve excursion at the wrist level when the terminal movement was at the cervical spine.

Conclusion

The largest median nerve excursion in the arm and wrist occurred when wrist extension is the terminal movement. Contralateral cervical lateral flexion with a prepositioned extended wrist produced the least motion of the median nerve at both sites.

2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 2: Role of Foraminal Ligaments in the Cervical Spine

STUDY DESIGN

A cross-sectional cadaveric examination of the mechanical effect of foraminal ligaments on cervical nerve root displacement and strain.

OBJECTIVE

To determine the role of foraminal ligaments by examining differences in cervical nerve root displacement and strain during upper limb neural tension testing (ULNTT) before and after selective cutting of foraminal ligaments.

SUMMARY OF BACKGROUND DATA

Although investigators have determined that lumbar spine foraminal ligaments limit displacement and strain of lumbosacral nerve roots, similar studies have not been conducted to prove that it is true for the cervical region. Because the size, shape, and orientation of cervical spine foraminal ligaments are similar to those in the lumbar spine, it is hypothesized that foraminal ligaments in the cervical spine will function in a similar fashion.

METHODS

Radiolucent markers were implanted into cervical nerve roots C5-C8 of 9 unembalmed cadavers. Posteroanterior fluoroscopic images were captured at resting and upper limb neural tension testing positioning before and after selective cutting of foraminal ligaments.

RESULTS

Selective cutting of foraminal ligaments resulted in significant increases in inferolateral displacement (average, 2.94 mm [ligaments intact]-3.87 mm [ligaments cut], P < 0.05) and strain (average, 9.33% [ligaments intact]-16.31% [ligaments cut], P < 0.03) of cervical nerve roots C5-C8 during upper limb neural tension testing.

CONCLUSION

Foraminal ligaments in the cervical spine limited cervical nerve root displacement and strain during upper limb neural tension testing. Foraminal ligaments seem to have a protective role, reducing displacement and strain to cervical nerve roots during tension events.

LEVEL OF EVIDENCE

2.

2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 1: A Minimally Invasive Assessment in Unembalmed Cadavers

STUDY DESIGN

A cross-sectional cadaveric examination of displacement and strain measured at the level of the cervical nerve roots during upper limb neural tension testing (ULNTT) with median nerve bias.

OBJECTIVE

To determine the displacement and strain of cervical nerve roots C5-C8 during ULNTT with minimal disruption of surrounding tissues.

SUMMARY OF BACKGROUND DATA

Clinical examination of neural pathology involving cervical nerve roots is difficult because of the transient nature of pathologies, such as cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. Cadaveric studies have demonstrated significant displacement and strain in lumbosacral nerve roots during neurodynamic testing of the lower extremity. Examination into the biomechanical behaviors of cervical nerve roots during ULNTT has not been performed.

METHODS

Eleven unembalmed cadavers were positioned supine as though undergoing ULNTT. Radiolucent markers were implanted into cervical nerve roots C5-C8. Posteroanterior fluoroscopic images were captured at resting and ULNTT positioning. Images were digitized and displacement and strain were calculated.

RESULTS

ULNTT resulted in significant inferolateral displacement (average, 2.16 mm-4.32 mm, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in inferolateral displacement between the C5 and C6 nerve roots (3.15 mm vs. 4.32 mm, P = 0.009). ULNTT resulted in significant strain (average, 6.80%-11.87%, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in strain between the C5 and C6 nerve roots (6.60% vs. 11.87%, P = 0.03).

CONCLUSION

ULNTT caused significant inferolateral displacement and strain in cervical nerve roots C5-C8. These results provide the mechanical foundation for the use of ULNTT in clinical evaluation of pathology in the cervical region, such as in cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome.

LEVEL OF EVIDENCE

2.

Tension of the ulnar, median, and radial nerves during ulnar nerve neurodynamic testing: observational cadaveric study

BACKGROUND

The ulnar nerve upper limb neurodynamic test (ULNT3) uses upper limb positioning to investigate symptoms arising from the ulnar nerve. It is proposed to selectively increase tension of the nerve; however, this property of the test is not well established.

OBJECTIVE

The aim of this study was to determine the upper limb position that results in: (1) the greatest tension of the ulnar nerve and (2) the greatest difference in tension between the ulnar nerve and the other 2 major nerves of the upper limb: median and radial.

DESIGN

This was an observational cadaver study.

METHODS

Tension (in newtons) of the ulnar, median, and radial nerves was measured simultaneously using 3 buckle force transducers in 5 upper limb positions in 10 embalmed human cadavers (N=20 limbs). Repeated-measures analysis of variance (ANOVA) with Bonferroni post hoc tests determined differences in tension among nerves and among limb positions.

RESULTS

The addition of shoulder horizontal abduction (H.Abd; 12.62 N; 95% confidence interval [95% CI]=10.76, 14.47) and combined shoulder abduction and internal rotation (H.Abd+IR; 11.86 N; 95% CI=9.96, 13.77) to ULNT3 (scapular depression, shoulder abduction and external rotation, elbow flexion, forearm pronation, and wrist and finger extension) produced significantly greater ulnar nerve tension compared with the ULNT3 alone (8.71 N; 95% CI=7.25, 10.17). The ULNT3+H.Abd test demonstrated the greatest difference in tension among nerves (mean difference between ulnar and median nerves=11.87 N; 95% CI=9.80, 13.92; mean difference between ulnar and radial nerves=8.47 N; 95% CI=6.41, 10.53).

LIMITATIONS

These results pertain only to the biomechanical plausibility of the ulnar nerve neurodynamic test and do not account for other factors that may affect the clinical application of this test.

CONCLUSIONS

The ULNT3+H.Abd is a biomechanically plausible test for detecting peripheral neuropathic pain related to the ulnar nerve. In situations where the shoulder complex will not tolerate the combination of shoulder external rotation in abduction, performing upper limb neurodynamic tests with internal rotation instead of external rotation is a biomechanically plausible alternative.

Morphometric Atlas Selection for Automatic Brachial Plexus Segmentation

PURPOSE

The purpose of this study was to determine the effects of atlas selection based on different morphometric parameters, on the accuracy of automatic brachial plexus (BP) segmentation for radiation therapy planning. The segmentation accuracy was measured by comparing all of the generated automatic segmentations with anatomically validated gold standard atlases developed using cadavers.

METHODS AND MATERIALS

Twelve cadaver computed tomography (CT) atlases (3 males, 9 females; mean age: 73 years) were included in the study. One atlas was selected to serve as a patient, and the other 11 atlases were registered separately onto this "patient" using deformable image registration. This procedure was repeated for every atlas as a patient. Next, the Dice and Jaccard similarity indices and inclusion index were calculated for every registered BP with the original gold standard BP. In parallel, differences in several morphometric parameters that may influence the BP segmentation accuracy were measured for the different atlases. Specific brachial plexus-related CT-visible bony points were used to define the morphometric parameters. Subsequently, correlations between the similarity indices and morphometric parameters were calculated.

RESULTS

A clear negative correlation between difference in protraction-retraction distance and the similarity indices was observed (mean Pearson correlation coefficient = -0.546). All of the other investigated Pearson correlation coefficients were weak.

CONCLUSIONS

Differences in the shoulder protraction-retraction position between the atlas and the patient during planning CT influence the BP autosegmentation accuracy. A greater difference in the protraction-retraction distance between the atlas and the patient reduces the accuracy of the BP automatic segmentation result.

Effect of glenohumeral forward flexion on upper limb myoelectric activity during simulated mills manipulation; relations to peripheral nerve biomechanics

BACKGROUND

It is generally accepted that muscles may activate via the common nociceptive flexion reflex (NFR) in response to painful stimuli associated with tensile or compressive forces on peripheral nerves. Following the basic assumption that the radial nerve may be stressed around the elbow during the execution of the Mills manipulation, two positions considered to have different mechanical effects on the radial nerve and the brachial plexus were tested in order to i) explore whether muscles are activated in certain patterns with concomitant changes in nerve tension, ii) establish whether muscle responses can be modified with mechanical unloading of the brachial plexus.

METHODS

Muscle responses were quantified bilaterally in eight subjects (N = 16) during Mills Manipulation (MM) pre-manipulative positioning and a Varied position that putatively produces less mechanical tension in the brachial plexus. End range pre-manipulative stretch was used in order to simulate the effects of Mills manipulation. Electromyographic signals were recorded with a 16 channel portable EMG unit and correlated with kinematic data from three charge-coupled device adjustable cameras which allowed for precise movement tracking.

RESULTS

Compared with the Standard Mills manipulation position, the Varied position produced significantly reduced myoelectric activity (P ≤ .001) in all test muscles. Additional subjective data support the notion that certain muscle activity patterns were protective.

CONCLUSION

It seems that protective muscles are selectively activated in a specific pattern in order to protect the radial nerve from mechanical tension by shortening its pathway, suggesting integration of muscle and neural mechanisms. Furthermore, the significantly decreased myoelectric activity with reduced mechanical tension in the brachial plexus may help controlling collateral effects of the Mills manipulation itself, making it potentially safer and more specific.

Intraoperative nerve monitoring during total shoulder arthroplasty surgery

BACKGROUND

Nerve injury is an acknowledged complication of total shoulder arthroplasty (TSA). Although the incidence of postoperative neurological deficit has been reported to be between 1% and 16%, the true incidence of nerve damage is considered to be higher. The present study aimed to identify the rate of intraoperative nerve injury during total shoulder arthroplasty and to determine potential risk factors.

METHODS

A prospective study of nerve conduction in 21 patients who underwent primary or revision TSA was carried out over a 12-month period. Nerve conduction was monitored by measuring intraoperative sensory evoked potentials (SEP). A significant neurophysiological signal change was defined as either a unilateral or bilateral decrease in SEP signal of ≥50%, a latency increase of ≥10% or a change in waveform morphology, not caused by operative or anaesthetic technique.

RESULTS

Seven (33%) patients had a SEP signal change. The only significant risk factor identified for signal change was male sex (odds ratio 15.00, 95% confidence interval). The median nerve was the most affected nerve in the operated arm. All but one signal change returned to normal before completion of the operation and no patient had a persisting postoperative clinical neurological deficit.

CONCLUSIONS

The incidence of intraoperative nerve damage may be more common than previously reported. However, the loss of SEP signal is reversible and does not correlate with persisting clinical neurological deficits. The median nerve appears to be most at risk. Monitoring SEPs in the operated limb during TSA may be a valuable tool during TSA.