A comparison of thermography and electromyography in the diagnosis of cervical radiculopathy

Evaluation of persons with suspected lumbosacral and cervical radiculopathy: Electrodiagnostic assessment and implications for treatment and outcomes (Part I)

Persons with back, neck, and limb symptoms constitute a major referral population to specialists in electrodiagnostic (EDX) medicine. The evaluation of these patients involves consideration of both the common and less common disorders. The EDX examination with needle electromyography (EMG) is the most important means of testing for radiculopathy. This test has modest sensitivity but high specificity and well complements imaging of the spine. Needle EMG in combination with nerve conduction testing is valuable in excluding entrapment neuropathies and polyneuropathy-conditions that frequently mimic radicular symptoms. In this first of a two-part review, the optimal EDX evaluation of persons with suspected radiculopathy is presented. In part two, the implications of EDX findings for diagnosis and clinical management of persons with radiculopathy are reviewed.

Sensory and sympathetic disorders in chronic non-specific neck pain

The signs of sympathetic and sensory nerve-related disorders are not widely investigated in chronic nonspecific neck pain (NNP) patients. Thus, we performed skin temperature (Tsk), evaporation and touch threshold (TT) measurements to reveal possible dysfunctions at the fingertips of NNP patients (n=60) compared with healthy controls (n=11). Neck pain intensity was the main modifier of Tsk, and age the main modifier of TT in a multivariate model. On comparisons of the subgroups of NNP patients with unilateral (n=26) and bilateral (n=34) symptoms and controls, TT differed and Tsk tended to differ, the unilateral pain patients being found to demonstrate higher TT values on both sides. Interrelations between the measured parameters were found in the controls, but not in the patients. The NNP patients exhibited signs of functional impairment of innervation reflected in changes in tactile sensitivity and vasoactive sympathetic function. These changes may be based on both central and peripheral mechanisms, which possibly differ in patients with unilateral and bilateral symptoms.

Changes in Body Temperature in Incomplete Spinal Cord Injury by Digital Infrared Thermographic Imaging

Objective

To investigate changes in the core temperature and body surface temperature in patients with incomplete spinal cord injuries (SCI). In incomplete SCI, the temperature change is difficult to see compared with complete spinal cord injuries. The goal of this study was to better understand thermal regulation in patients with incomplete SCI.

Methods

Fifty-six SCI patients were enrolled, and the control group consisted of 20 healthy persons. The spinal cord injuries were classified according to International Standards for Neurological Classification of Spinal Cord Injury. The patients were classified into two groups: upper (neurological injury level T6 or above) and lower (neurological injury level T7 or below) SCIs. Body core temperature was measured using an oral thermometer, and body surface temperature was measured using digital infrared thermographic imaging.

Results

Twenty-nine patients had upper spinal cord injuries, 27 patients had lower SCIs, and 20 persons served as the normal healthy persons. Comparing the skin temperatures of the three groups, the temperatures at the lower abdomen, anterior thigh and anterior tibia in the patients with upper SCIs were lower than those of the normal healthy persons and the patients with lower SCIs. No significant temperature differences were observed between the normal healthy persons and the patients with lower SCIs.

Conclusion

In our study, we found thermal dysregulation in patients with incomplete SCI. In particular, body surface temperature regulation was worse in upper SCIs than in lower injuries. Moreover, cord injury severity affected body surface temperature regulation in SCI patients.

Skin temperature changes in patients with unilateral lumbosacral radiculopathy

Objective

To clarify the relationship of skin temperature changes to clinical, radiologic, and electrophysiological findings in unilateral lumbosacral radiculopathy and to delineate the possible temperature-change mechanisms involved.

Methods

One hundred and one patients who had clinical symptoms and for whom there were physical findings suggestive or indicative of unilateral lumbosacral radiculopathy, along with 27 normal controls, were selected for the study, and the thermal-pattern results of digital infrared thermographic imaging (DITI) performed on the back and lower extremities were analyzed. Local temperatures were assessed by comparing the mean temperature differences (ΔT) in 30 regions of interest (ROIs), and abnormal thermal patterns were divided into seven regions. To aid the diagnosis of radiculopathy, magnetic resonance imaging (MRI) and electrophysiological tests were also carried out.

Results

The incidence of disc herniation on MRI was 86%; 43% of patients showed electrophysiological abnormalities. On DITI, 97% of the patients showed abnormal ΔT in at least one of the 30 ROIs, and 79% showed hypothermia on the involved side. Seventy-eight percent of the patients also showed abnormal thermal patterns in at least one of the seven regions. Patients who had motor weakness or lateral-type disc herniation showed some correlations with abnormal DITI findings. However, neither pain severity nor other physical or electrophysiological findings were related to the DITI findings.

Conclusion

Skin temperature change following lumbosacral radiculopathy was related to some clinical and MRI findings, suggesting muscle atrophy. DITI, despite its limitations, might be useful as a complementary tool in the diagnosis of unilateral lumbosacral radiculopathy.

Evaluating the patient with suspected radiculopathy

Persons with back, neck, and limb symptoms are commonly seen by health care providers. They constitute a major referral population to specialists in electrodiagnostic medicine. The evaluation of these patients involves consideration of both the common and less common disorders. The electrodiagnostic examination with needle electromyography is the most important means of testing for radiculopathy. This test has modest sensitivity but high specificity. It complements imaging of the spine. Electromyography in combination with nerve conduction testing is valuable in excluding entrapment neuropathies and polyneuropathy, conditions that frequently mimic radicular symptoms. A streamlined examination with 6 muscles, 1 of which is the paraspinal, has a high diagnostic yield, yet minimizes patient discomfort and examiner time. This article presents an overview of the electrodiagnostic evaluation for patients with suspected radiculopathy.

Are the infrared thermography findings skin temperature-dependent? a study on neck pain patients

BACKGROUND

Skin temperature (Tsk) disorders have been proposed as sign of impaired innervation in several conditions, but the influence of different factors on the infrared thermography (IRT) findings remains unclear.

METHODS

The relations between the Tsk and δT (side-to-side temperature difference) values, and influence of age, gender, anthropometric characteristics and pain intensity on those values were analysed in non-specific neck pain (NP) patients (n = 91) using mixed model analysis. IRT findings were also compared in subgroups of NP patients: with cold (CHNPP, n = 21) or warm hands (WHNPP, n = 56) and healthy controls, with cold (CHC, n = 11) or warm hands (WHC, n = 19). Also, the stability of δT values in CHNPP was examined.

RESULTS

Only the area of measurement and the actual Tsk influenced the δT values. CHNPP demonstrated higher δT values in distal parts, compared with WHNPP and controls, but those values vanished when their hands turned warm. δT values in CHNPP were related to the pain intensity. The findings of WHNPP and WHC did not differ.

CONCLUSION

Our results suggest that the δT values as signs of impaired Tsk regulation are dynamic and better detectable in cold skin. The results underline the need of caution in interpretation of IRT findings.

The Electrodiagnosis of Cervical and Lumbosacral Radiculopathy

This article reviews the usefulness of the electrodiagnostic examination in patients who have suspected cervical and lumbosacral radiculopathy. This study can verify the presence and severity of radiculopathy, determine which levels are involved, and provide an electrodiagnostic correlate to imaging abnormalities. A practical approach for conducting the nerve conduction portion and needle electrode examination in these patients is discussed.

Electrodiagnostic approach to patients with suspected radiculopathy

This article reviews the electrodiagnostic testing for persons suspected of having radiculopathies and the expected sensitivities that different testing modalities provide. One cannot minimize the importance of the clinical evaluation and differential diagnosis formulation by the electrodiagnostician to guide testing. The needle EMG examination is the most useful electrodiagnostic test but is limited in sensitivity. Electromyographic screening examinations using six muscles are possible that optimize identification yet minimize patient discomfort. Electrodiagnostic findings must be interpreted relative to the patient's clinical presentation, and the consultant should tailor the electrodiagnostic study to the clinical situation.

Side-to-side confrontational strength-testing for weakness of the intrinsic muscles of the hand

A prospective study of 217 patients was performed to determine the sensitivity and specificity of standard manual testing and of a new method, termed confrontational testing, for detecting weakness of the intrinsic muscles of the hand. Electrodiagnostic testing was used to identify the presence of any neurological disorder and to provide a control for the manual testing methods. Standard manual testing of the muscles innervated by the ulnar nerve revealed a sensitivity of 14 per cent, a specificity of 100 per cent, a predictive value of a positive result of 100 per cent, and a predictive value of a negative result of 57 per cent. Confrontational testing of the muscles innervated by the ulnar nerve revealed a sensitivity of 82 per cent, a specificity of 100 per cent, a predictive value of a positive result of 100 per cent, and a predictive value of a negative result of 87 per cent. Standard manual testing of the muscles innervated by the median nerve revealed a sensitivity of 6 per cent, a specificity of 100 per cent, a predictive value of a positive result of 100 per cent, and a predictive value of a negative result of 49 per cent. Confrontational testing of the muscles innervated by the median nerve revealed a sensitivity of 16 per cent, a specificity of 100 per cent, a predictive value of a positive result of 100 per cent, and a predictive value of a negative result of 52 per cent.