Electrodiagnosis of neck pain

A review of electromyography techniques of the cervical paraspinal muscles

Electrodiagnosis for cervical radiculopathy often involves exploration of the cervical paraspinal muscles. Accurate and reproducible results require a technique with specific anatomic localization, direction of insertion, extent of insertion, scoring system for insertion, and criteria for determining abnormality. We sought to understand if a published technique met these criteria. A Medline search found 39 articles with original research and 10 review articles involving the cervical paraspinals. A library search found 19 textbooks since 2000, but 9 were not available. Only two studies were specific to the question. Neither had reproducible techniques and they contradicted each other. Studies in which the paraspinals were used for comparison or inclusion did not provide any specific technique. The review articles and textbooks typically met none of our criteria and the few that discussed technique at all provided no reproducible methods. Despite 80 years of electrodiagnostic testing, there is no useful, reproducible technique for exploring the cervical paraspinal muscles. Yet such a paraspinal mapping technique has proven invaluable in the lumbar region. For cervical electromyography to be of value, the next step is to understand the anatomy and propose a reproducible technique. Subsequent research will determine whether the neck muscles are helpful in the diagnosis of cervical radiculopathy. The absence of a valid reproducible cervical paraspinal technique impedes clinical and scientific understanding of cervical radiculopathy.

Characteristics of carpal tunnel syndrome in patients with cervical radiculopathy: A cross-sectional study

Background and Aims

Cervical radiculopathy (CR) is a group of signs and symptoms caused by cervical root dysfunction. Patients with this condition may also have carpal tunnel syndrome (CTS), which is caused by compression of the median nerve in the carpal tunnel. This coexistent condition is referred to as double crush syndrome (DCS) which is explained by proximal disruption in axoplasmic flow that may result in nerve dysfunction. Yet, the accuracy of this hypothesis remains controversial.

Materials and Methods

Patients with confirmed CR according to electromyography were included in this retrospective study. However, we omitted patients with overt diabetic neuropathy, prior spinal or hand surgery and/or fractures, and rheumatoid arthritis. Patients underwent electrodiagnostic studies, and the results were used to determine CTS severity. We used Pearson's χ 2 test to assess the correlation between the severity of CTS and CR. Descriptive analysis was used to report patient characteristics and the prevalence of CTS in CR patients.

Results

We included 291 participants, 59% of whom were women. Although insignificant, DCS was observed more in women (n = 110) compared to men (n = 71). However, we found that patients with DCS (54.81 ± 13.3) were older than non-DCS patients (43.71 ± 12.94) which was statistically significant (p < 0.05). There was statistically no correlation between the severity of CR and CTS, ipsilaterlly (p > 0.05). In total, CTS was observed in 62.2% (n = 181) patients.

Conclusion

In summary, we found a relatively high prevalence of DCS in the present study. In patients with and without DCS, gender did not seem to play a role but the growing age seemed to contribute to DCS. The severity of CTS was not related to CR severity at any cervical level, which negates a causal relation between the pre-existing CR and newly diagnosed CTS.

2. Cervical radicular pain

INTRODUCTION

Cervical radicular pain is pain perceived in the upper limb, caused by irritation or compression of a cervical spine nerve, the roots of the nerve, or both.

METHODS

The literature on the diagnosis and treatment of cervical radicular pain was retrieved and summarized.

RESULTS

The diagnosis is made by combining elements from the patient's history, physical examination, and supplementary tests. The Spurling and shoulder abduction tests are the two most common examinations used to identify cervical radicular pain. MRI without contrast, CT scanning, and in some cases plain radiography can all be appropriate imaging techniques for nontraumatic cervical radiculopathy. MRI is recommended prior to interventional treatments. Exercise with or without other treatments can be beneficial. There is scant evidence for the use of paracetamol, nonsteroidal anti-inflammatory drugs, and neuropathic pain medications such as gabapentin, pregabalin, tricyclic antidepressants, and anticonvulsants for the treatment of radicular pain. Acute and subacute cervical radicular pain may respond well to epidural corticosteroid administration, preferentially using an interlaminar approach. By contrast, for chronic cervical radicular pain, the efficacy of epidural corticosteroid administration is limited. In these patients, pulsed radiofrequency treatment adjacent to the dorsal root ganglion may be considered.

CONCLUSIONS

There is currently no gold standard for the diagnosis of cervical radicular pain. There is scant evidence for the use of medication. Epidural corticosteroid injection and pulsed radiofrequency adjacent to the dorsal root ganglion may be considered. [Correction added on 12 June 2023, after first online publication: The preceding sentence was corrected.].

Granisetron vs. lidocaine injection to trigger points in the management of myofascial pain syndrome: a double-blind randomized clinical trial

OBJECTIVES

Granisetron and lidocaine injections have been used for the management of myofascial pain syndrome. This study was aimed to compare the efficacy of granisetron and lidocaine injections to trigger points of upper trapezius in the management of myofascial pain syndrome.

METHODS

We performed a double-blind randomized clinical trial in an outpatient clinic of physical medicine and rehabilitation at a teaching hospital. A total of 40 patients aged ≥18 with neck pain due to myofascial pain syndrome were included. They had pain for at least one month with the intensity of at least 30 mm on a 100 mm visual analog scale. Each participant received a single dose of 1 mL lidocaine 2% or 1 mg (in 1 mL) granisetron. The solutions were injected into a maximum of three trigger points of the upper trapezius. We instructed all patients to remain active while avoiding strenuous activity for three or four days, and to perform stretch exercise and massage of their upper trapezius muscles. We assessed the patients before the interventions, and one month and three months post-injection. The primary outcome was the Neck Disability Index and the secondary outcome was the Neck Pain and Disability Scale.

RESULTS

Both interventions were successful in reducing neck pain and disability (all p-values <0.001). However, the neck pain and disability responded more favorably to lidocaine than granisetron (p=0.001 for Neck Disability Index, and p=0.006 for Neck Pain and Disability Scale). No significant side-effect was recognized for both groups.

CONCLUSIONS

Both lidocaine and granisetron injections to trigger points are effective and safe for the management of the syndrome and the benefits remain at least for three months. However, lidocaine is more effective in reducing pain and disability. The injections are well-tolerated, although a transient pain at the site of injections is a common complaint. One mL of lidocaine 2% is more effective than 1 mg (in 1 mL) granisetron for injecting into the trigger points of the upper trapezius in myofascial pain syndrome.

Cervical Radiculopathy Focus on Characteristics and Differential Diagnosis

Cervical radiculopathy is characterized by neurological dysfunction caused by compression and inflammation of the spinal nerves or nerve roots of the cervical spine. It mainly presents with neck and arm pain, sensory loss, motor dysfunction, and reflex changes according to the dermatomal distribution. The most common causes of cervical radiculopathy are cervical disc herniation and cervical spondylosis. It is important to find the exact symptomatic segment and distinguish between conditions that may mimic certain cervical radicular compression syndromes through meticulous physical examinations and precise reading of radiographs. Non-surgical treatments are recommended as an initial management. Surgery is applicable to patients with intractable or persistent pain despite sufficient conservative management or with severe or progressive neurological deficits. Cervical radiculopathy is treated surgically by anterior and/or posterior approaches. The appropriate choice of surgical treatment should be individualized, considering the patient’s main pathophysiology, specific clinical symptoms and radiographic findings thoroughly.

The study of diagnostic efficacy of nerve conduction study parameters in cervical radiculopathy

BACKGROUND

Cervical Radiculopathy (CR) is a neurologic condition characterised by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. Diagnostic criteria for CR are not well defined, and no universally accepted criteria for its diagnosis have been established. Clinical examination, radiological imaging and electrophysiologic evaluation are the different modalities to diagnose CR. The incidence of Cervical Spondylosis and related conditions is increasing in the present scenario and the use of radiologic examination is time consuming and uneconomical for the common Indian setup. Thus, there is a definite need to establish a cost effective, reliable, and accurate means for establishing the diagnosis of cervical radiculopathy. Electrodiagnostic tests are the closest to fulfill these criteria.

AIM

To evaluate diagnostic utility of various motor and sensory nerve conduction study parameters in cervical radiculopathy.

SETTING AND DESIGN

It was a cross-sectional study conducted on 100 subjects of age > 40 years.

MATERIAL AND METHODS

The consecutive patients clinically diagnosed to have cervical radiculopathy, referred from department of Orthopaedics were prospectively recruited for the motor and sensory nerve conduction study using RMS EMG EP Mark-II. Parameters studied were Compound Muscle Action Potential (CMAP), Distal Motor Latency (DML) and Conduction Velocity (CV) for motor nerves and Sensory Nerve Action Potential (SNAP) and CV for sensory nerves.

STATISTICAL ANALYSIS

Study observations and results were analysed to find the Specificity, Sensitivity, Positive Predictive Value and Negative Predictive Value using SPSS 16.0.

RESULTS

Among various motor nerve conduction parameters CMAP was found to be more sensitive with high positive predicative value. CV was found to have greater specificity and DML had least negative predictive value. Sensory nerve conduction parameters were found to have less sensitivity but higher specificity as compared to motor parameters.

CONCLUSION

Nerve conduction studies are useful supportive diagnostic tool for suspected cervical radiculopathy as they are found to have reliable sensitivity and specificity.

What is the best way to apply the Spurling test for cervical radiculopathy?

BACKGROUND

A diagnosis of cervical radiculopathy is based largely on clinical examination, including provocative testing. The most common maneuver was described in 1944 by Spurling and Scoville. Since then, several modifications of the original maneuver have been proposed to improve its value in the diagnosis of cervical radiculopathy.

QUESTIONS/PURPOSES

We assessed the ability of six known variations of the Spurling test to reproduce the complaints of patients diagnosed with cervical radiculopathy.

METHODS

We prospectively enrolled 67 patients presenting with cervical radicular-like symptoms and concordant radiographic findings. Each patient underwent six distinct provocative cervical spine maneuvers by two examiners, during which three parameters were recorded: (1) pain intensity (VAS score), (2) paresthesia intensity (0 - no paresthesia, 1 - mild to moderate, and 2 - severe), and (3) characteristic pain distribution (0 - no pain, 1 - neck pain only, 2 - arm pain only, 3 - pain elicited distal to the elbow). The interobserver reliability of the reported VAS score (measured by the intraclass coefficient correlation) ranged from 0.78 to 0.96 and the calculated kappa values of the categorical parameters ranged from 0.58 to 1.0 for paresthesia intensity and from 0.63 to 1.0 for pain distribution. Differences in scores elicited between the two examiners for the 67 patients were resolved by consensus.

RESULTS

A maneuver consisting of extension, lateral bending, and axial compression resulted in the highest VAS score (mean, 7) and was associated with the most distally elicited pain on average (mean, 2.5). The highest paresthesia levels were reported after applying extension, rotation, and axial compression (mean, 1). These maneuvers, however, were the least tolerable, causing discontinuation of the examination on three occasions.

CONCLUSIONS

Whenever cervical radiculopathy is suspected our observations suggest the staged provocative maneuvers that should be included in the physical evaluation are extension and lateral bending first, followed by the addition of axial compression in cases with an inconclusive effect.

Dropped Shoulder Syndrome: A Cause of Lower Cervical Radiculopathy

Background and Purpose

Cervical radiculopathy is a pathological process involving a nerve root of the cervical spine. The most common causes of radiculopathy are cervical disc herniation followed by cervical spondylosis. The aim of this study was to determine the effect of dropped shoulder as a cause of lower cervical radiculopathy.

Methods

In total, 132 patients, comprising 105 women (79.5%) and 27 men (20.5%; female : male ratio of 4 : 1) and a mean age of 36.7 years (range 18-58 years), were included in this study. All of the patients presented with shoulder pain, and were investigated by cervical X-ray, cervical magnetic resonance imaging, serum muscle enzymes, and electromyography (EMG)/nerve-conduction studies.

Results

Ninety six patients (72.7%) exhibited visually detectable dropped shoulder. The lateral view X-ray of the cervical region revealed eight or more vertebrae. In 119 patients (90.2%), the EMG revealed a mild-to-moderate or moderate denervation patterns in the abductor digiti minimi, first dorsal interosseous, and flexor carpi ulnaris muscles, while the abductor pollicis brevis, extensor carpi radialis, and triceps brachii were denervated in 102 patients (77.3%). All of the patients had lower cervical paraspinal muscles with a denervation pattern.

Conclusions

Three criteria for diagnosing dropped shoulder syndrome have been suggested: pain with consistent anatomical distribution, X-ray abnormalities, and EMG abnormalities. Compression of the cervical roots by muscle spasm has been proposed as the cause of dropped shoulder syndrome; this possibility is discussed herein.

A systematic review of the diagnostic accuracy of provocative tests of the neck for diagnosing cervical radiculopathy

Clinical provocative tests of the neck, which position the neck and arm inorder to aggravate or relieve arm symptoms, are commonly used in clinical practice in patients with a suspected cervical radiculopathy. Their diagnostic accuracy, however, has never been examined in a systematic review. A comprehensive search was conducted in order to identify all possible studies fulfilling the inclusion criteria. A study was included if: (1) any provocative test of the neck for diagnosing cervical radiculopathy was identified; (2) any reference standard was used; (3) sensitivity and specificity were reported or could be (re-)calculated; and, (4) the publication was a full report. Two reviewers independently selected studies, and assessed methodological quality. Only six studies met the inclusion criteria, which evaluated five provocative tests. In general, Spurling's test demonstrated low to moderate sensitivity and high specificity, as did traction/neck distraction, and Valsalva's maneuver. The upper limb tension test (ULTT) demonstrated high sensitivity and low specificity, while the shoulder abduction test demonstrated low to moderate sensitivity and moderate to high specificity. Common methodological flaws included lack of an optimal reference standard, disease progression bias, spectrum bias, and review bias. Limitations include few primary studies, substantial heterogeneity, and numerous methodological flaws among the studies; therefore, a meta-analysis was not conducted. This review suggests that, when consistent with the history and other physical findings, a positive Spurling's, traction/neck distraction, and Valsalva's might be indicative of a cervical radiculopathy, while a negative ULTT might be used to rule it out. However, the lack of evidence precludes any firm conclusions regarding their diagnostic value, especially when used in primary care. More high quality studies are necessary in order to resolve this issue.