Ultrasonographic reference values for assessing normal radial nerve ultrasonography in the normal population

Role of neuro-sonography of peripheral nerves as a diagnostic and a differentiation tool of amyotrophic lateral sclerosis

Background

Motor neuron disease is a heterogeneous group of progressive neurodegenerative disorders, most common of which is amyotrophic lateral sclerosis (ALS). There are many clinical and radiological criteria to diagnose amyotrophic lateral sclerosis and to differentiate it from other motor neuron disease and neurodegenerative disorders. Neuro-sonography is one of the easily applied tools to diagnose and differentiate ALS. ALS diagnosis is delayed up to 3 years according to some authors due to the wide differential diagnosis, with cervical degeneration being a common misdiagnosis. The objective of this study was to evaluate the role of neuro-sonography in diagnosis and differentiation of amyotrophic lateral sclerosis from other causes of progressive mixed upper and lower motor neuron lesion.

Results

A total neuro-sonography score at a cut-off point (≤ 127) predicted patients with ALS, with good (85%) accuracy, sensitivity = 73% and specificity = 83% (p < 0.01) and Lt median arm score at a cut-off point (≤ 6) predicted patients with ALS, with good (88%) accuracy, sensitivity = 86% and specificity = 86% (p < 0.01) and the median nerve at the arm level was the most sensitive and specific nerve to predict patients with ALS.

Conclusion

Neuro-sonography of peripheral nerves is a recent, noninvasive, accessible technique that can be used in early diagnosis of ALS.

Reference values for the cross-sectional area of normal radial nerve at two levels using high-resolution ultrasonography

Aim of the study

High-resolution ultrasound is less often used to evaluate the radial nerves. The radial nerve is often involved in entrapment syndromes. The aim of the study is to establish the reference values for the cross-sectional area of the normal radial nerve on high-resolution ultrasonography, and to identify relationships between the cross-sectional area and the subject’s age, gender, height, weight, body mass index, and hand dominance.

Material and methods

The study was conducted on 200 subjects of both sexes, between 18 and 75 years of age, who did not have history of peripheral neuropathy or trauma to the upper limb. High-resolution real-time sonographic examination of the radial nerves was performed in both arms at two different levels. Level 1 was taken just proximal to the nerve bifurcation, and level 2 just after the nerve exits the spiral grove.

Results

The mean cross-sectional area measured at level 2 (4.3 ± 0.4 mm²) was greater than that measured at level 1 (2.3 ± 0.3 mm²). No significant relationship was seen with age and hand dominance (p >0.05), but the cross-sectional area values at above mentioned levels were larger in males than in females (p <0.05). In addition, the cross-sectional areas of the radial nerves showed a positive correlation with height, weight, and body mass index (p <0.05).

Conclusion

The established ultrasonographic reference values along with basic clinical data will aid in the diagnosis, response to treatment, and prognostic evaluation of peripheral neuropathies.

Ultrasound-Guided Percutaneous Neuromodulation in Patients with Chronic Lateral Epicondylalgia: A Pilot Randomized Clinical Trial

OBJECTIVE

The aim was to analyze effects of a percutaneous neuromodulation (PNM) treatment on the radial nerve, regarding pain, functionality, electrophysiologic excitability, and morphology, in patients with chronic lateral epicondylalgia (LE).

METHODS

Twenty-four patients with chronic unilateral elbow pain were recruited for this preliminary study and were divided into two groups: control (n = 12) and PNM group (n = 12). The subjects in the PNM group received percutaneous peripheral neurostimulation with an acupuncture needle that was located next to the nerve with ultrasound guidance. Pain using a numerical rating scale (NRS), functional ability using patient-rated tennis elbow evaluation (PRTEE), radial nerve cross-sectional area measured by ultrasound, and chronaxie and accommodation index (AI) measured by the strength-duration curve were evaluated.

RESULTS

Both groups showed no differences in the baseline measurements (all p = 0.001). However, at the end of the treatment, there were significant differences between groups since only the PNM group significantly improved their values compared to their baseline values: level of pain and cross-sectional area (CSA) values showed a significant decrease while the PRTEE scores showed a significant improvement. Then, regarding AI, the PNM group showed significant improvement for the electrophysiologic nerve excitability pattern, reporting normal function in all radial nerves after treatment (p = 0.001). However, chronaxie values always reported similar values with no differences between groups (p >0.05); Conclusion: Ultrasound-PNM technique may be an interesting therapeutic tool for the treatment of chronic LE due to the improvement in the level of pain, functionality, nerve morphology, and excitability in this population.

The Efficacy of Ultrasound for Visualizing Radial Nerve Lesions with Coexistent Plate Fixation of Humeral Shaft Fractures

INTRODUCTION

Ultrasound has been commonly employed for depicting the morphology of the lesions in patients with radial nerve neuropathy, including entrapment, tumor, trauma, and iatrogenic injury. However, few studies have evaluated the efficacy of ultrasound for visualizing radial nerve lesions with coexistent plate fixation of humeral shaft fractures. This study aimed to address this special clinical issue.

METHODS

We retrospectively examined the efficacy of ultrasound for visualizing radial nerve lesions with coexistent plate fixation of humeral shaft fractures based on intraoperative findings in patients who were treated in our hospital from January 2007 to June 2019.

RESULTS

Forty-six patients were included, and there was a 100% concordance between the ultrasound and intraoperative findings on radial nerve lesions. Ultrasonography revealed four types of lesions: radial nerve in continuity in thirty-one patients, neuroma in continuity in four patients, radial nerve stuck under the plate in three patients, and radial nerve transection in eight patients. The lesion radial nerve in continuity comprised two situations according to intraoperative electrodiagnostic test results, which could not be differentiated by ultrasonography, radial nerve in continuity treated with neurolysis in twenty-five patients and radial nerve in continuity treated with nerve graft in six patients.

CONCLUSION

Ultrasonography can accurately depict radial nerve lesions with coexistent plate fixation of humeral shaft fractures. It provides a basis for determining the extent of nerve damage in all patients except those with the lesion radial nerve in continuity, which is conducive to making treatment decisions as early as possible.

Anterior minimally invasive plating osteosynthesis technique (MIPO) for humeral shaft fractures: an anatomical study of neuromuscular structures at risk

OBJECTIVE

The aim of this study was to evaluate the neuromuscular structures at risk during modified anterior minimally invasive plating osteosynthesis technique (Belangero-Livani) for humeral shaft fractures.

METHODS

Eight fresh-frozen human specimens ranging from 38 to 82 years old were used. Specimens were positioned supine with the shoulder in 70° abduction and the forearm in full supination. Anterior minimally invasive plating osteosynthesis technique according to Belangero-Livani technique was performed in each specimen. Under radioscopic control, the plate was introduced in retrograde fashion through the subbrachialis path. Anatomical structures were inspected and different anatomical parameters were measured after dissection at the end of the surgical procedures. Measurements were performed using a high digital caliper. Statistical analysis was performed using the Pearson's correlation coefficient test. A p value of < 0.05 was used to define statistical significance.

RESULTS

There were no macroscopic lesions of myotendinous or neurovascular structures in any specimen. The mean distance between the radial nerve to the distal lateral end of the plate was 8.63 mm (range 4.14-13.83 mm). The mean total length of the humerus was 328.59 mm. We found a significant direct correlation between the total length of the humerus and both specimen height and weight.

CONCLUSION

The modified Belangero-Livani anterior MIPO technique for humeral shaft fractures performed in retrograde fashion is safe and useful, without major risk to the soft tissue of the anterior compartment of the arm, including the radial nerve in the lateral intermuscular septum. Intraoperative dissection, avoiding deep lateral retraction on the distal approach, minimizes the risk of radial nerve damage. Strict surgical planning and appreciation for the anatomic landmarks can reduce the risk of damage to neuromuscular structures.

LEVEL OF EVIDENCE

Level IV; Case series with no comparison group; Treatment study.

Strength-Duration Curves of Radial Nerve in Patients With Lateral Elbow Pain

CONTEXT

Lateral epicondylalgia (LE) refers to a painful condition at or around the lateral epicondyle of the humerus. LE is one of the most common injuries of the elbow; however, the cause of the pathology is not clear. Patients often experience symptoms consistent with a radial nerve injury; however, data on the involvement of the radial nerve are needed.

OBJECTIVE

To analyze the relationship between electrophysiologic excitability and morphology of the radial nerve in patients with unilateral chronic LE.

DESIGN

Cross-sectional study.

SETTING

Department of Physiotherapy, University of Seville.

PATIENTS

A total of 56 elbows (28 right, 28 left) in 28 patients (12 females, 16 males; age 49 [7.37] y) were recruited by convenience sampling.

MAIN OUTCOME MEASURES

Strength-duration curves (chronaxia and accommodation index) and cross-sectional area (CSA) of the radial nerve were made in all participants. All parameters were compared between both limbs. Also, pain with palpation in the lateral epicondyle and functional pain of involved extremities was assessed using visual analog scale and the Patient-Rated Tennis Elbow Evaluation, respectively.

RESULTS

Symptomatic limb showed higher CSA values of the radial nerve when compared with the asymptomatic limb (P < .001). On the symptomatic limb, duration of symptoms was positively correlated with CSA values. Chronaxia values were all normal and similar between both limbs (P = .35). Regarding accommodation index, 14 (54%) patients showed accommodation indices that suggested pathological radial nerve on the right limb, 4 (14%) on the left limb, 5 (18%) on both limbs, and 4 (14%) had none of the affected nerves. Eight-six percent of patients showed accommodation indices that suggested pathological radial nerve, independently of symptomatic limb. In these cases, affected nerves had higher CSA than the unaffected nerve (P = .01). On the affected nerves, duration of symptoms was positively correlated with accommodation indices.

CONCLUSIONS

These findings suggest that patients with unilateral chronic LE show a decreased excitability in any radial nerve, independently of the symptomatic limb, and that pathological nerves have higher CSA than the nonpathological nerves.

Shear wave elastography evaluation of the median and tibial nerve in diabetic peripheral neuropathy

Background

To evaluate the value of shear wave elastography (SWE) in the detection of diabetic peripheral neuropathy (DPN) of the median and tibial nerves.

Methods

The study included 40 DPN patients, 40 diabetic mellitus (DM) patients without DPN, and 40 healthy subjects. High-resolution ultrasonography (US) and SWE were performed on the median nerve (MN) and tibial nerve (TN), and cross-sectional area (CSA) and nerve stiffness were measured. ROC analysis was also performed.

Results

The patients with DPN demonstrated higher stiffness of the median and tibial nerve compared with that of healthy volunteers and DM patients (P<0.001). Bilateral analysis showed that there was no significant difference in nerve stiffness between the left and right median nerves and tibial nerves in DPN patients (P>0.05). The stiffness of median nerve and tibial nerve in each one side also had no significant difference in patients with DPN (P>0.05). The CSA of the tibial nerve in the DPN group was significantly larger than that in the other groups (P<0.001), while there was no significant difference of median nerve CSA among the three groups (P>0.05). The area under curve (AUC) of SWE (MN: 0.899, TN: 0.927) to diagnose DPN was significantly greater than that of CSA (TN: 0.798). The optimal cut-off value in SWE of the tibial nerve and median nerve for diagnosis of DPN was 4.11 and 4.06 m/s, respectively, with a good sensitivity and specificity.

Conclusions

Median and tibial nerve stiffness was significantly higher in patients with DPN. These findings suggest that SWE-based stiffness measurement of the nerve was a better method than CSA, and it can be used as another effective assistant method in the diagnosis of DPN.

Investigation of the Diagnostic Value of Ultrasonography for Radial Neuropathy Located at the Spiral Groove

Objective

To determine a diagnostic cut-off value for the cross-sectional area (CSA) of the radial nerve using ultrasonography for radial neuropathy located at the spiral groove (SG).

Methods

Seventeen patients with electrodiagnostic evidence of radial neuropathy at the SG and 30 healthy controls underwent ultrasonography of the radial nerve at the SG . The CSAs at the SG were compared in the patient and control groups. The CSA at the SG between the symptomatic and asymptomatic sides (ΔSx–Asx and Sx/Asx, respectively) were analyzed to obtain the optimal cut-off value. The relationship between the electrophysiological severity of radial neuropathy and CSA was also evaluated.

Results

Among the variables examined, there were statistically significant differences in the CSA between the patient and control groups, ΔSx–Asx, and Sx/Asx at the SG. In a receiver operating characteristics analysis, the cut-off CSA was 5.75 mm² at the SG (sensitivity 52.9%, specificity 90%), 1.75 mm² for ΔSx–Asx (sensitivity 58.8%, specificity 100%), and 1.22 mm² for Sx/Asx (sensitivity 70.6%, specificity 93.3%) in diagnosing radial neuropathy at the SG. There was no significant correlation between CSA and electrophysiological severity score for either patient group.

Conclusion

The reference value obtained for CSA of the radial nerve at the SG may facilitate investigation of radial nerve pathologies at the SG.

Ultrasonographic reference values for the deep branch of the radial nerve at the arcade of Frohse

PURPOSE

The deep branch of the radial nerve (DBRN) enters the forearm as it passes under the arcade of Frohse. This is the most common entrapment site of the DBRN in the forearm. In this study, we investigated the ultrasonographic reference values for the diameters and cross-sectional area (CSA) of the DBRN at the level of the arcade of Frohse in a healthy sample of the population.

METHODS

Sixty-five healthy Caucasian volunteers (130 nerves) were recruited for this study. The reference range [mean ± 2 standard deviations (SD); 2.5th-97.5th quintiles] and the upper limit of the side-to-side difference were determined. The effects of age, gender, handedness, height, and body mass index were examined.

RESULTS

The mean age was 41.8 ± 11.2 years (range 18-75 years). The mean ± 2SD of the CSA was 0.50-1.42 mm². The upper limit of the normal side-to-side difference was 0.35 mm². The differences between males and females and between the dominant and non-dominant arms were not significant. The mean anteroposterior and transverse diameters were 0.83 ± 0.13 and 1.23 ± 0.29 mm, respectively. A significant correlation between the dominant-side CSA and age (r = 0.41; p < 0.001) was observed. The correlations between CSA and height (r = 0.19; p = 0.12) and body mass index (r = 0.22; p = 0.07) were not significant.

CONCLUSION

The measurements obtained in this study are valuable for examining DBRN pathologies using high-frequency ultrasound. The findings showed that age was associated with the DBRN CSA, while gender, height, and body mass index were not.

Ultrasonographic Reference Values for Assessing Normal Sciatic Nerve Ultrasonography in the Normal Population

Objective:

High-resolution ultrasonography (HRUS) has been used recently to characterize median and ulnar nerves but is seldom used to characterize the lower extremity nerves. The reference standard for normal the lower extremity nerves has not been established. Thus, this study measured the cross-sectional areas (CSAs) of the sciatic nerve of 200 healthy male or female volunteers, aged 18–80 using HRUS. These data provide basic clinical data for the use of high-resolution ultrasound for the future diagnosis, treatment, and prognostic evaluation of peripheral neuropathies.

Methods:

Two hundred healthy volunteers with 400 lower extremities were studied with HRUS. According to their age, the subjects were assigned to young group (18-30 years, n = 75), middle group. (31-60 years, n = 70), and old group(61-80 year, n = 55). Age, sex, height, weight were recorded and CSAs of sciatic nerve were obtained at every predetermined sites.

Results:

The mean CSAs of sciatic nerves at GS and MGPF were 0.527 ± 0.028 cm² and 0.444 ± 0.026 cm² respectively. Pearson's correlation analysis showed that the mean CSAs were correlated with height and weight. There was no difference in mean CSAs among the three groups (P > 0.05). Women had smaller CSAs of the normal Sciatic nerves than men in two measuring sites (GS, MGPF) (P < 0.05).

Conclusion:

Peripheral nerve ultrasonography is a reliable and reproducible diagnostic method in the hands of experienced examiners. Normal values for the sciatic nerve nerves are provided by our study. Thus, reference values of Sciatic nerve CSA of the lower extremity can facilitate the analysis of abnormal nerve conditions.

Ultrasonographic reference values for the median nerve at the level of pronator teres muscle

PURPOSE

The purpose of this study was to investigate the ultrasonographic reference values for diameters and cross-sectional area (CSA) of the median nerve between the two heads of the pronator teres muscle in healthy population as well as to correlate the findings with height, weight, sex and age.

METHODS

Fifty-five healthy Caucasian volunteers (110 median nerves) were included in this study. The reference range (mean ± 2 standard deviations; 2.5th-97.5th quintiles) and the upper limit of side-to-side difference of the median nerve between the two heads of the pronator teres muscle were investigated using high-frequency ultrasound. The effects of age, sex, height, handedness, and body mass index (BMI) were examined.

RESULTS

The mean age was 39.4 ± 10.6 years (range 18-75 years). The mean ± 2SD of the median CSA was 4.9-12.9 mm². The upper limit of normal side-to-side difference was 3.0 mm². The differences between genders and between the dominant and non-dominant hands were not significant. The mean antero-posterior and transverse diameters were 7.2 ± 1.5 and 10.7 ± 2.4 mm, respectively. Significant correlations were observed between the dominant-side CSA and BMI (r = 0.33; p = 0.01) and age (r = 0.31; p = 0.02). The correlation between the CSA and height (r = 0.19; p = 0.16) was not significant.

CONCLUSIONS

The measurements obtained in this study are of importance for examining median nerve entrapments in the forearm using high-frequency ultrasound. Age and BMI showed to be correlated with median nerve CSA; while gender and height were not.

Diaphragm abnormalities in heart failure and aging: mechanisms and integration of cardiovascular and respiratory pathophysiology

Inspiratory function is essential for alveolar ventilation and expulsive behaviors that promote airway clearance (e.g., coughing and sneezing). Current evidence demonstrates that inspiratory dysfunction occurs during healthy aging and is accentuated by chronic heart failure (CHF). This inspiratory dysfunction contributes to key aspects of CHF and aging cardiovascular and pulmonary pathophysiology including: (1) impaired airway clearance and predisposition to pneumonia; (2) inability to sustain ventilation during physical activity; (3) shallow breathing pattern that limits alveolar ventilation and gas exchange; and (4) sympathetic activation that causes cardiac arrhythmias and tissue vasoconstriction. The diaphragm is the primary inspiratory muscle; hence, its neuromuscular integrity is a main determinant of the adequacy of inspiratory function. Mechanistic work within animal and cellular models has revealed specific factors that may be responsible for diaphragm neuromuscular abnormalities in CHF and aging. These include phrenic nerve and neuromuscular junction alterations as well as intrinsic myocyte abnormalities, such as changes in the quantity and quality of contractile proteins, accelerated fiber atrophy, and shifts in fiber type distribution. CHF, aging, or CHF in the presence of aging disturbs the dynamics of circulating factors (e.g., cytokines and angiotensin II) and cell signaling involving sphingolipids, reactive oxygen species, and proteolytic pathways, thus leading to the previously listed abnormalities. Exercise-based rehabilitation combined with pharmacological therapies targeting the pathways reviewed herein hold promise to treat diaphragm abnormalities and inspiratory muscle dysfunction in CHF and aging.

Estimation of ultrasound reference values for the upper limb peripheral nerves in adults: A cross-sectional study

The objective of this study is to estimate the reference values for the upper limb peripheral nerves in adults.The demographics and physical characteristics of 69 adult healthy volunteers were evaluated and recorded. In addition, the side to side differences of the estimated reference values and their correlations with the age, weight, height, and body mass index (BMI) were evaluated.Cross-sectional area reference values of the upper limb nerves did not correlate with height; however, they correlated with age, weight, and BMI in some scanned sites.The data obtained in this study could be helpful in future diagnosis of peripheral nerve disorders of the upper limb.

The feasibility of using high-resolution ultrasonography to assess ulnar nerve in patients with diabetes mellitus

OBJECTIVE

The aim of this study was to investigate the usefulness of high-resolution ultrasonography for the diagnosis of polyneuropathy in diabetes mellitus patients by the examination of the ulnar nerves.

METHOD

We recruited 100 healthy age-matched volunteers (50 women and 50 men) with 200 arms without diabetes or cubital tunnel syndrome as the control group. We assessed the upper limbs of 100 diabetes mellitus patients (45 women and 55 men), 40 of whom had electrophysiologically confirmed diabetic peripheral neuropathy and 60 had no diabetic peripheral neuropathy in the upper limbs. Age, sex, height and weight were recorded and the cross-sectional area of the ulnar nerve was measured at every predetermined site.

RESULTS

The cross-sectional area of the ulnar nerve was measured at six sites (mid-humerus, inlet of the cubital tunnel, outlet of the cubital tunnel, upon the medial epicondyle, 6 cm upon the wrist crease and Guyon tunnel). The ulnar nerve in two measuring sites (mid-humerus, upon the medial epicondyle) in the control group showed a statistical difference between men and women (p < 0.05). There was no statistical difference in the cross-sectional area in the control group when dominant and non-dominant arms were compared. The cross-sectional area was larger in the diabetic peripheral neuropathy group in three sites (inlet of the cubital tunnel, outlet of the cubital tunnel, Guyon tunnel) compared with those in the control group.

CONCLUSION

High-resolution ultrasonography may be helpful in the early diagnosis of peripheral neuropathy in diabetic patients.

Peripheral Nerve Ultrasound in Small Fiber Polyneuropathy

Routine nerve conduction studies are normal in patients with small fiber neuropathy (SFN), and a definitive diagnosis is based on skin biopsy revealing reduced intra-epidermal nerve fiber density (IENFD). In large fiber polyneuropathy, ultrasound (US) parameters indicate enlargement in cross-sectional area (CSA). This study was aimed at determining if similar changes in large fibers on US are apparent in patients with SFN. Twenty-five patients with SFN diagnosed by reduced IENFD and 25 age- and body mass index (BMI)-matched healthy controls underwent US studies of sural and superficial peroneal sensory nerves. The mean CSA of the sural nerve in SFN patients was 3.2 ± 0.8 mm(2), and in controls, 2.7 ± 0.6 mm(2) (p < 0.0070), and this was independent of sex. There was no difference in the thickness-to-width ratio or echogenicity of the nerves. US of the sural nerve in patients diagnosed with small fiber neuropathy reveals an enlarged cross-sectional area similar to that in large fiber polyneuropathy.