Electrodiagnostic approach to patients with suspected radiculopathy

Electrodiagnostic Confirmation of Lumbar Radiculopathy and Its Association With Lumbar Central Canal Stenosis and Neuroforaminal Stenosis

INTRODUCTION

Lumbar spinal stenosis (LSS) and lumbar neuroforaminal stenosis (LNS) are common diagnoses that plague patients with low back pain. Electrodiagnostic testing (EDX) can be used as an adjunct to investigate lower extremity radicular nerve pain and/or neurogenic claudication. However, there are only limited studies discussing the association of these diagnostic tools with radiculopathy. We investigate the association between EDX-confirmed radiculopathy and the degree of LSS and LNS found on MRI.

METHODS

A retrospective cohort study of patients presenting to an outpatient pain medicine clinic who had a documented EDX and lumbar MRI. We used a Pearson chi-square test to compare the severity of radiographic LSS/LNS with EDX data. The data were fit to a multivariable logistic regression model.

RESULTS

There were not any statistically significant correlations when comparing EDX evidence of radiculopathy and LSS (p = 0.50), LSS severity (p = 0.54), LNS (p = 0.69), or LNS severity (p = 0.11).

CONCLUSIONS

We found no significant associations between LSS/LNS severity and EDX findings. The presence and degree of severity of LSS/LNS on MRI were not reliable predictors of EDX findings.

Motor Evoked Potentials after Supraspinal Stimulation in Pre- and Postoperative Evaluations of Patients with Cervical Radiculopathy

Objective

Pre- and postoperative comparative evaluation of neurophysiological tests and clinical trials. Analysis of the diagnostic value of motor evoked potentials (MEP) induced by a magnetic field after supraspinal stimulation. Evaluation of the sensitivity and specificity of electromyography (EMG) and MEP is achieved.

Methods

EMG, ENG, M-wave, F-wave, and MEP tests were performed on 35 patients with confirmed cervical radiculopathy in pre- and postoperative evaluations. The clinical trial consisted of evaluation of muscle strength, a sensory perception test and evaluation of tendon reflexes and pain severity.

Results

The sensitivity of the resting EMG and MEP tests is 24%-67% and 6%-27%, while their specificity is 43%-80% and 86%-100%, respectively. The postoperative evaluation revealed a statistically significant reduction in pain severity (p=0001), an increase in muscle strength in DP (p=0.0431), BB (p=0,0431), and TB (p=0.0272), and improvement of touch sensation in terms of dermatomal innervation in C5 (p=0.0001) and C6 (p=0.0044).

Conclusions

Tests comparing MRI sensitivity to neurophysiological tests show that neuroimaging is more sensitive in diagnostics of patients with cervical radiculopathy; however, clinical neurophysiology tests are more specific in reference to clinical trials.

Great toe drop following knee ligament reconstruction: A case report

Case Description: A 17-year-old male post anterior cruciate ligament reconstruction complained of the inability to extend his great toe immediately following surgery. Background: Neurological injuries following knee arthroscopy have been reported to occur between 0.6%-2.5%. The most commonly injured nerves are the saphenous and common fibular nerve (CFN). Great toe-drop secondary to isolated denervation of the extensor hallucis longus (EHL), has only been reported one time in the literature. This report describes a case of isolated denervation of the EHL following knee cruciate ligament reconstruction. A detailed description of the anatomy of the CFN is reviewed as well as how electroneuromyographic (EMG/NCS) testing can assist in the diagnosis, prognosis, and intervention of this type of injury. Outcomes: EHL paralysis did not functionally limit the patient from participating in a post-surgical rehabilitation regime. The patient successfully completed his ACL reconstruction rehabilitation and was released to return to sporting activities 9 months postsurgery. Twelve months post-surgery, the patient regained full great toe extension and strength. Discussion: It is important to note that physical therapists can identify the need for, refer, and in some instances perform EMG/NCS testing on patients with neuromuscular disorders. Isolated injury of the CFN branch that innervates the EHL is extremely rare. Understanding the anatomy of the CFN and its branches is critical for the physical therapist when performing an examination and interpreting the findings. It is also important to understand the potential causes and management approaches following this type of injury.

Asymmetric Atrophy of Paraspinal Muscles in Patients With Chronic Unilateral Lumbar Radiculopathy

Objective

To assess the cross-sectional area (CSA) of the muscles for investigating the occurrence of asymmetry of the paraspinal (multifidus and erector spinae) and psoas muscles and its relation to the chronicity of unilateral lumbar radiculopathy using magnetic resonance imaging (MRI).

Methods

This retrospective study was conducted between January 2012 to December 2014. Sixty one patients with unilateral L5 radiculopathy were enrolled: 30 patients had a symptom duration less than 3 months (group A) and 31 patients had a symptom duration of 3 months or more (group B). Axial MRI measured the CSA of the paraspinal and psoas muscles at the middle between the lower margin of the upper vertebra and upper margin of the lower vertebra, and obtained the relative CSA (rCSA) which is the ratio of the CSA of muscles to that of the lower margin of L4 vertebra.

Results

There were no differences in the demographics between the two groups. In group B, rCSA of the erector spinae at the L4–5 level, and that of multifidus at the L4–5 and L5–S1 levels, were significantly smaller on the involved side as compared with the uninvolved side. In contrast, no significant muscle asymmetry was observed in group A. The rCSA of the psoas was not affected in either group.

Conclusion

The atrophy of the multifidus and erector spinae ipsilateral to the lumbar radiculopathy was observed only in patients suffering from unilateral radiculopathy for 3 months or more.

Late Responses in the Electrodiagnosis of Cervical Radiculopathies

Backround and aim

This paper aims to assess the parameters of late responses and then determine their usefulness in patients with cervical radiculopathy.

Patients and methods

We studied a total of 114 patients with bilateral assessment of median and ulnar nerves and of F and A waves parameters.

Results

We draw attention to the need of bilateral electrodiagnostic examination due to changes occurring in a third of cases also in the asymptomatic limb. Pluriradicular injuries occurred in one third of cases. The root that was most commonly affected in cases of uniradicular lesion was C7. The parameters with the most important alterations were persistence, tacheodispersion and chronodispersion, which were changed in about a half of the patients. With regard to the A wave, it occurred in a small number of cases, about 10%, with an average amplitude of about 120 μV and an average latency of 15ms. The distance from the point of stimulation where the collateral branch appeared was calculated to be approximately 35 cm.

Conclusions

Among the F wave parameters, persistence, tacheodispersion and chronodispersion are recommended to be studied; these parameters were also included in the composite score along with the AAEM recommendations.

The prognostic value of electrodiagnostic testing in patients with sciatica receiving physical therapy

PURPOSE

To investigate the prognostic value of electrodiagnostic testing in patients with sciatica receiving physical therapy.

METHODS

Electrodiagnostic testing was performed on 38 patients with sciatica participating in a randomized trial comparing different physical therapy interventions. Patients were grouped and analyzed according to the presence or absence of radiculopathy based on electrodiagnostic testing. Longitudinal data analysis was conducted using multilevel growth modeling with ten waves of data collected from baseline through the treatment and post-treatment periods up to 6 months. The primary outcome measure was changes in low back pain-related disability assessed using the Roland and Morris disability questionnaire (RMDQ).

RESULTS

Patients with radiculopathy (n = 19) had statistically significant and clinically meaningful improvements in RMDQ scores at every post-treatment follow-up occasion regardless of treatment received. The final multilevel growth model revealed improvements in RMDQ scores in patients with radiculopathy at the 6-week (-8.1, 95 % CI -12.6 to -2.6; P = 0.006) and 6-month (-4.1, 95 % CI -7.4 to -0.7; P = 0.020) follow-up occasions compared to patients without radiculopathy. Treatment group was not a significant predictive factor at any follow-up occasion. An interaction between electrodiagnostic status and time revealed faster weekly improvements in RMDQ scores in patients with radiculopathy at the 6-week (-0.72, 95 % CI -1.4 to -0.04; P = 0.040) through the 16-week (-0.30, 95 % CI, -0.57 to -0.04; P = 0.028) follow-up occasions compared to patients without radiculopathy.

CONCLUSIONS

The presence of lumbosacral radiculopathy identified with electrodiagnostic testing is a favorable prognostic factor for recovery in low back pain-related disability regardless of physical therapy treatment received.

The relationship between history and physical examination findings and the outcome of electrodiagnostic testing in patients with sciatica referred to physical therapy

STUDY DESIGN

Cross-sectional diagnostic accuracy study.

OBJECTIVE

To investigate the relationship between history and physical examination findings and the outcome of electrodiagnostic testing in patients with sciatica referred to physical therapy.

BACKGROUND

Electrodiagnostic testing is routinely used to evaluate patients with sciatica. Recent evidence suggests that the presence of radiculopathy identified with electrodiagnostic testing may predict better functional outcomes in these patients. While some patient history and physical examination findings have been shown to predict the presence of disc herniation or neurological insult, little is known about their relationship to the results of electrodiagnostic testing.

METHODS

Electrodiagnostic testing was performed on 38 patients with sciatica who participated in a randomized trial that compared different physical therapy interventions. The diagnostic gold standard was the presence or absence of radiculopathy, based on the results of the needle electromyographic examination. Diagnostic sensitivity and specificity values were calculated, along with corresponding likelihood ratios, for select patient history and physical examination variables.

RESULTS

No significant relationship was found between select patient history and physical examination findings, analyzed individually or in combination, and the outcome of electrodiagnostic testing. Diagnostic sensitivity values ranged from 0.03 (95% confidence interval [CI]: 0.00, 0.24) to a high of 0.95 (95% CI: 0.72, 0.99), and specificity values ranged from 0.10 (95% CI: 0.02, 0.34) to a high of 0.95 (95% CI: 0.72, 0.99). Positive likelihood ratios ranged from 0.15 (95% CI: 0.01, 2.87) to a high of 2.33 (95% CI: 0.71, 7.70), and negative likelihood ratios ranged from 2.00 (95% CI: 0.35, 11.48) to a low of 0.50 (95% CI: 0.03, 8.10).

CONCLUSION

In this investigation, the relationship between patient history and physical examination findings and the outcome of electrodiagnostic testing among patients with sciatica was not found to be statistically significant or clinically meaningful. However, given the small sample size and corresponding large CIs, these results should be considered with caution, recognizing that some of the history and physical examination variables may prove useful in future research. These findings suggest that electrodiagnostic testing is essential to identify the subgroup of patients with sciatica who have measurable nerve injury consistent with radiculopathy, which may be an important prognostic factor for recovery. Level of Evidence Diagnosis, level 3b-. J Orthop Sports Phys Ther 2014;44(7):508-517. Epub 22 May 2014. doi:10.2519/jospt.2014.5002.

Axon count and sympathetic skin responses in lumbosacral radiculopathy

Background and Purpose

Electrodiagnostic studies can be used to confirm the diagnosis of lumbosacral radiculopathies, but more sensitive diagnostic methods are often needed to measure the ensuing motor neuronal loss and sympathetic failure.

Methods

Twenty-six patients with lumbar radiculopathy and 30 controls were investigated using nerve conduction studies, motor unit number estimation (MUNE), testing of the sympathetic skin response (SSR), quantitative electromyography (QEMG), and magnetic resonance myelography (MRM).

Results

Using QEMG as the gold standard, the sensitivity and specificity of MUNE for the abductor hallucis longus muscle were 71.4% and 70%, respectively. While they were 75% and 68.8%, respectively, when used MRM as gold standard. The sensitivity and specificity of MUNE for the extensor digitorum brevis muscle were 100% and 84.1%, respectively, when the peroneal motor amplitude as the gold standard. The SSR latency was slightly longer in the patients than in the controls.

Conclusions

MUNE is a simple and sensitive test for evaluating autonomic function and for diagnosing lumbosacral radiculopathy in patients. MUNE could be used routinely as a guide for the rehabilitation of patients with radiculopathies. SSR measurements may reveal subtle sympathetic abnormalities in patients with lumbosacral radiculopathy.

Clinical findings and electrodiagnostic testing in 108 consecutive cases of lumbosacral radiculopathy due to herniated disc

STUDY AIM

This prospective study aim to examine whether clinical findings and electrodiagnostic testing (EDX) in patients with lumbosacral monoradiculopathy due to herniated disc (HD) differ as a function of root involvement level (L5 vs. S1) and HD zone (paramedian vs. intraforaminal).

PATIENTS AND METHODS

All patients with L4, L5 or S1 monoradiculopathy were prospectively enrolled at four electromyography (EMG) labs over a 2-year period. The diagnosis was based on a congruence between patient history and MRI evidence of HD. We compared the sensitivities of clinical findings and EDX with respect to both root involvement level and HD zone. Multivariate logistic regression was performed in order to verify the association between abnormal EMG, clinical, and neuroradiological findings.

RESULTS

One hundred and eight patients (mean age 47.7 years, 55% men) were consecutively enrolled. Sensory loss in the painful dermatome was the most frequent finding at physical examination (56% of cases). EMG was abnormal in at least one muscle supplied by femoral and sciatic nerves in 45 cases (42%). Inclusion of paraspinal muscles increased sensitivity to only 49% and that of proximal muscles was useless. Motor and sensory neurography was seldom abnormal. The most frequent motor neurographic abnormalities were a delay of F-wave minimum latency and decrease in the compound muscle action potential amplitude from extensor digitorum brevis and abductor hallucis in L5 and S1 radiculopathies, respectively. Sensory neurography was usually normal, the amplitude of sensory nerve action potential was seldom reduced when HD injured dorsal root ganglion or postganglionic root fibres. Multivariate logistic regression analysis showed that EMG abnormalities could be predicted by myotomal muscular weakness, abnormal deep reflexes, and paraesthesiae. The only clinical and electrophysiological differences with respect to root involvement level concerned deep reflexes and motor neurography of deep peroneal and tibial nerves.

CONCLUSIONS

Only some EDX parameters are helpful for the diagnosis of lumbosacral radiculopathy. EMG was abnormal in less than 50% of cases and its abnormalities could be predicted by some clinical findings. However, neurography is useful as a tool for differential diagnosis between radiculopathy and more diffuse disorders of the peripheral nervous system (polyneuropathy, plexopathy).

EMG/NCS in the evaluation of spine trauma with radicular symptoms

In the management of spine trauma with radicular symptoms (STRS), EMG/nerve conduction studies (NCS) often have low combined sensitivity and specificity in confirming root injury. The anatomic level of injury may not correspond to the root level. Paraspinal studies are nonlocalizing and can be falsely positive and negative. Unlike MRI and CT imaging, EMG/NCS do not reveal the biological morphology of the lesion. There are no studies that confirm the efficacy of EMG/NCS in the management of STRS. EMG/NCS may be indicated if there is a differential diagnosis between a root and distal neuropathic/myopathic lesion. Otherwise, as shown in this series of cases typically referred for outpatient EMG/NCS testing, there is limited evidence to support the use of often uncomfortable and costly EMG/NCS in STRS.

Neurological complications of ankylosing spondylitis: neurophysiological assessment

Studies examined the neurological involvement of ankylosing spondylitis (AS) are limited. This study aimed to assess the frequency of myelopathy, radiculopathy and myopathy in AS correlating them to the clinical, radiological and laboratory parameters. Included were 24 patients with AS. Axial status was assessed using bath ankylosing spondylitis metrology index (BASMI). Patients underwent (a) standard cervical and lumbar spine and sacroiliac joint radiography, (b) somatosensory (SSEP) and magnetic motor (MEP) evoked potentials of upper and lower limbs, (c) electromyography (EMG) of trapezius and supraspinatus muscles. Patients' mean age and duration of illness were 36 and 5.99 years. Bath ankylosing spondylitis metrology index mean score was 4.6. Twenty-five percent (n = 6) of patients had neurological manifestations, 8.3% of them had myelopathy and 16.7% had radiculopathy. Ossification of the posterior (OPLL) and anterior (OALL) longitudinal ligaments were found in 8.3% (n = 2) and 4.2% (n = 1). About 70.8% (n = 17) had >or=1 neurophysiological test abnormalities. Twelve patients (50%) had SSEP abnormalities, seven had prolonged central conduction time (CCT) of median and/or ulnar nerves suggesting cervical myelopathy. Six had delayed peripheral or root latencies at Erb's or interpeak latency (Erb's-C5) suggesting radiculopathy. Motor evoked potentials was abnormal in 54% (n = 13). Twelve (50%) and five (20.8%) patients had abnormal MEP of upper limbs and lower limbs, respectively. About 50% (n = 12) had myopathic features of trapezius and supraspinatus muscles. Only 8.3% (n = 2) had neuropathic features. We concluded that subclinical neurological complications are frequent in AS compared to clinically manifest complications. Somatosensory evoked potential and MEP are useful to identify AS patients prone to develop neurological complications.

Asymmetric atrophy of multifidus muscle in patients with unilateral lumbosacral radiculopathy

STUDY DESIGN

Prospective case-control study of multifidus muscle atrophy in 39 patients with unilateral lumbosacral radiculopathy and lumbosacral disc herniation and 20 controls.

OBJECTIVE

To evaluate quantitatively the asymmetry of multifidus muscles in unilateral lumbosacral radiculopathy with disc herniation (herniated intervertebral disc; HIVD) by using magnetic resonance imaging (MRI).

SUMMARY OF BACKGROUND DATA

Histologic and morphologic changes of multifidus muscles have been reported in lumbosacral disc herniation, but there are few imaging studies on the changes of multifidus muscles in unilateral radiculopathy.

METHODS

Bilateral multifidus muscles in L3-L4, L4-L5, and L5-S1 levels were detected in fast spin-echo T1 axial MRI images. The total cross-sectional area (CSA) of multifidus muscles (TMA) and the density of pure muscle CSA (PMA) were measured by a computerized analysis program, and the ratios of PMA to TMA (PMA/TMA) and the PMA ratios of involved to uninvolved sides (IMA/UMA) were calculated. The patients were divided into 2 groups according to the electrodiagnosis results: a radiculopathy (RAD) group and an HIVD group without definite radiculopathy.

RESULTS

Fourteen patients had lumbosacral radiculopathies (RAD group) while 25 had no radiculopathy (HIVD group). No significant difference was found between the RAD and HIVD groups in TMA, PMA, and PMA/TMA. In terms of the criteria for the upper limit of IMA/UMA, 78.6% in the RAD group had an abnormal IMA/UMA ratio in at least 1 level, compared with 24% in the HIVD group and 10% in the control group. Thus, more cases with less muscle volume in the involved side were seen in the RAD group than in the HIVD and control groups.

CONCLUSION

Asymmetry of the multifidus muscles as seen in MRI was a useful finding to assess patients who had unilateral lumbosacral radiculopathy with HIVD. This may reflect the denervation of multifidus muscles in lumbosacral radiculopathy.

The logical choice of muscles for the needle-EMG evaluation of lumbosacral radiculopathy

The objective of this study was to find the theoretically smallest subsets of muscles for needle-EMG (nEMG) screening of lumbosacral radiculopathies that ascertain that each root and its adjacent roots are represented by at least two muscles each, innervated by those roots via different peripheral nerves. A 23 and a 30 muscles muscle-sets and their myotomal innervation where derived from the literature, and rearranged into 15 and 19 unique muscle-groups by root and peripheral nerve innervation. All 2(15) and 2(19) subset combinations thereof were respectively identified. The criteria above were computed for each subset and the smallest subsets that qualified were retained. The number of muscles sampled per damaged root and the number of muscles sampled per adjacent roots in compliance with the objective above were computed. The smallest subsets satisfying the objective above were of 6, 7 and 9 muscles each, and are enumerated in . From these tables, each electromyographer may choose a set that best suits him, confident of its diagnostic parameters, while inflicting the least pain onto his patients, utilizing the shortest possible procedure, concluding a screen of all the roots at once, a screen that best differentiate between normal and damaged roots, and in most cases adequate for reaching the final diagnosis. Moreover, when needed, each set may be the basis for a more extensive workup.

Resolution of pronounced painless weakness arising from radiculopathy and disk extrusion

In this retrospective, consecutive case series, we report the nonsurgical and rehabilitation outcomes of consecutive patients who presented with pronounced painless weakness arising from disk extrusion. Seven consecutive patients who chose physiatric care were followed clinically, and strength return was monitored. Each presented with predominantly painless radiculopathy, functionally significant strength loss, and radiographic evidence of disk extrusion or sequestration. Each patient participated in a targeted strengthening program, and in some cases, transforaminal injection therapy was employed. Each patient demonstrated an eventual full functional recovery. In most cases, electrodiagnostic studies were performed and included a needle examination of the affected limb and compound muscle action potentials from the most clinically relevant and weakened limb muscle. The electrodiagnostic findings and, in particular, the quantitative compound muscle action potential data seemed to correlate with the timing of motor recovery. Patients with predominantly painless and significant weakness arising from disk extrusion can demonstrate successful rehabilitation outcomes. Despite a relative absence of pain, such patients can present with a more rapidly reversible neurapraxic type of weakness. The more quantitative compound muscle action potential data obtained through electrodiagnostic studies may offer the treating physician an additional means of characterizing the type of neuronal injury at play and the likelihood and timing of strength return.

The logical choice of muscles for the needle-electromyography evaluation of cervical radiculopathy

OBJECTIVE

To find the theoretically smallest subsets of muscles for needle-electromyography screening of cervical radiculopathies that meet or exceed the American Association of Electrodiagnostic Medicine (AAEM) guideline: ascertaining that each root and its adjacent roots are represented by at least 2 muscles each, innervated by those roots via different peripheral nerves.

DESIGN

Twenty-two and 36 muscle sets and their myotomal innervation were derived from the literature, and rearranged into 15 and 23 unique muscle groups by root and peripheral nerve innervation. All 2 circumflex 15 and 2 circumflex 23 subsets thereof were respectively identified. The best approximations that met or exceeded the AAEM criteria were computed for each subset and the smallest subsets that qualified were retained.

SETTING

Electromyography laboratory.

PARTICIPANTS

None.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Compliance with or exceeding the AAEM guideline in the number of muscles sampled per damaged root and the number of muscles sampled per adjacent normal roots.

RESULTS

The smallest subsets satisfying or exceeding the AAEM guideline are of 8, 9, and 10 muscles each, and are enumerated in tables 3 and 4 in this article.

CONCLUSIONS

Electromyographers may choose a set or sets from tables in this article that best suits them, with confidence that they comply with or exceed the AAEM guideline while causing minimal pain to their patients and using the shortest possible procedure. All the roots can be screened at once to best differentiate between normal and damaged roots, and, in most cases, to reach a final diagnosis. Nonetheless, when needed, each set may be the basis for a more extensive workup.