Henry C. Tong

The Spurling test and cervical radiculopathy.

Study Design. A cross-sectional study design was used. Objective. To determine the sensitivity and specificity of the Spurling test for cervical radiculopathy. Summary of Background Data. The Spurling test is an accepted physical examination test, but there is little data on its sensitivity or specificity. Methods. From 1988 to 1993, 255 consecutive patients were referred for electrodiagnosis of upper extremity nerve disorders. A Spurling test administered before other testing was performed. The Spurling test was scored as positive if it caused pain or tingling that started in the shoulder and radiated distally to the elbow. After the electrodiagnostic examination, a score was given to each diagnosis in the differential diagnosis according to the likelihood of its presence. To determine the odds ratio, sensitivity, and specificity, &khgr;2 analysis was used. Also, the percentage of subjects with positive results from the Spurling test was calculated for several nerve disease diagnoses. Results. The Spurling test had a sensitivity of 6/20 (30%) and a specificity of 160/172 (93%). The results were positive in 16.6% of the normal group, in 3.4% of the group with nerve disorders other than a radiculopathy, in 25% of the group with an abnormality not consistent with any specific diagnosis group, in 37.5% of the group with possible radiculopathy, and in 40% of the group with certain radiculopathy. Conclusions. The Spurling test is not very sensitive, but it is specific for cervical radiculopathy diagnosed by electromyography. Therefore, it is not useful as a screening test, but it is clinically useful in helping to confirm a cervical radiculopathy.

Electromyographic and Magnetic Resonance Imaging to Predict Lumbar Stenosis, Low-Back Pain, and No Back Symptoms

BACKGROUND Magnetic resonance imaging is commonly used to diagnose lumbar spinal stenosis. Some persons without symptoms have a small lumbar spinal canal. Electrodiagnosis has been used to diagnose spinal stenosis for over sixty years, but we are aware of no masked, controlled trials of the use of electrodiagnosis for that purpose. This study was performed to evaluate the relationships of magnetic resonance imaging measures and electrodiagnostic data with the clinical syndrome of spinal stenosis. METHODS One hundred and fifty persons between the ages of fifty-five and eighty years old, including asymptomatic volunteers and persons referred for lumbar magnetic resonance imaging, underwent clinical examination, electrodiagnosis, and magnetic resonance imaging. Subjects were excluded if they had neuromuscular disease, sacral cancer, or inadequate test results, which left 126 subjects for the final analysis. The final cohort was divided into three groups--no back pain, mechanical back pain, and clinical spinal stenosis--on the basis of the impression of the examining physician, for whom the results of the magnetic resonance imaging and electrodiagnostic testing were masked. A spine surgeon also reviewed both the imaging and clinical examination data. RESULTS The examining physicians diagnosis of clinical spinal stenosis was significantly related to the neurological findings on examination (p < 0.05) and to the spine surgeons diagnosis (p < 0.001). The diagnosis of clinical spinal stenosis was also significantly related to the presence of fibrillations on electrodiagnostic testing (p < or = 0.003), the minimum anteroposterior diameter of the spinal canal on the magnetic resonance images (p = 0.016), and the average of the two smallest spinal canal diameters (p = 0.008) on the images. Measurements on magnetic resonance imaging did not differentiate subjects with clinical spinal stenosis from controls better than chance, whereas paraspinal mapping electrodiagnosis scores did. CONCLUSIONS This prospective, controlled, masked study of electrodiagnosis and magnetic resonance imaging for older subjects showed that imaging does not differentiate symptomatic from asymptomatic persons, whereas electrodiagnosis does. We believe that radiographic findings alone are insufficient to justify treatment for spinal stenosis.

The sensitivity and specificity of electrodiagnostic testing for the clinical syndrome of lumbar spinal stenosis

Study Design. Prospective, masked, double controlled diagnostic trial. Objectives. To determine the sensitivity and specificity of electrodiagnostic consultation (EDX) for the clinical syndrome of lumbar spinal stenosis. Summary of Background Data. EDX has been used for more than 50 years to diagnose spinal disorders but has not met the new standards of evidence-based medicine. Methods. A total of 150 subjects (asymptomatic volunteers and patients with MRIs suggesting back pain or spinal stenosis; 55–80 years of age) underwent physiatrist history and physical examination, MRI, and review of this data by a neurosurgeon, with each clinician masked to any outside information, leading to a unanimous consensus on diagnosis in 55. After masked EDX testing, 7 subjects with undiagnosed neuromuscular disease were discovered. EDX findings were related to “clinical gold standard” diagnoses in 48 persons. Results. Paraspinal mapping EMG score of >4 had 100% specificity and 30% sensitivity for stenosis compared with either the back pain or asymptomatic groups (each, P < 0.04). A composite limb and paraspinal fibrillation score had a sensitivity of 47.8% and specificity of 87.5% (P = 0.008), and H-wave sensitivity was 36.4, specificity 91.3 (P = 0.026) for stenosis versus all controls. Conclusions. This first masked study in the 60-year history of needle electromyography also introduces anatomically validated needle placement, quantified and reproducible examination of the paraspinal muscles, and dual control populations to EDX research in spinal disorders. EDX has statistically significant, clinically meaningful specificity for spinal stenosis and detects neuromuscular diseases that may masquerade as stenosis.

Spinal canal size and clinical symptoms among persons diagnosed with lumbar spinal stenosis

ObjectiveClinical symptoms associated with lumbar spinal stenosis (LSS) are believed to be due to neurogenic claudication caused by narrowing of the central and lateral spinal canals. However, there is a paucity of published data on these relationships. The purpose of the present study was to examine the relationship between clinical symptoms associated with LSS and osseous anterior-posterior (AP) spinal canal diameter as measured on axial magnetic resonance imaging. DesignCross-sectional study conducted at a University Spine Program. Fifty persons with a clinical diagnosis of LSS were administered measures of clinical pain and perceived function. Walking distance in the laboratory and community was also assessed. Participants also underwent magnetic resonance imaging of the spine. ResultsUsing recommended upper limits from the literature, patients with smaller canals reported greater perceived disability, but no other group differences emerged. In the entire sample, AP spinal canal diameter was not significantly associated with any of the clinical symptom measures examined. Body mass index was found to be significantly related to walking distance, but not perceived function or pain. ConclusionsAP spinal canal diameter is not predictive of clinical symptoms associated with LSS. The findings also suggest that body mass may play a significant role in functional limitations observed in this population.

Predictors of pain and function in persons with spinal stenosis, low back pain, and no back pain.

Study Design. Longitudinal masked, double-controlled cohort study. Objectives. To determine prognosis and predictors of function and pain in persons with spinal stenosis. Summary of Background Data. The clinical syndrome of spinal stenosis is common and disabling, but not clearly related to anatomic measures. Prognosis not well studied. Methods. Persons 55 to 80 years of age with and without stenosis on preliminary review of magnetic resonance imaging (MRI), and asymptomatic volunteers underwent screening, questionnaires, physical examination, ambulation testing, masked electromyogram (EMG), and masked MRI scans; these were repeated at >18 months. Results. Twenty-three asymptomatic, 28 back pain, and 32 clinically diagnosed stenosis subjects underwent follow-up. Although initial and follow-up diagnosis tended to agree (kappa = 0.394, P < 001), there were substantial shifts between the three groups. Among persons with clinically diagnosed stenosis, every measure trended for improvement, including significant changes in pain, ambulation, and EMG. Ambulation velocity and Pain Disability Index at follow-up were predicted by initial disability measures. Pain was predicted by initial sleep difficulty but not initial pain. EMG and MRI did not predict function or pain. Conclusion. Clinically recognized spinal stenosis is fluctuating and largely improving, and in continuum with back pain and no symptoms. Since anatomic and neurologic deficits do not predict future function, they should not be weighed heavily in surgical risk-benefit discussions.

Comparing Pain Severity and Functional Status of Older Adults without Spinal Symptoms, with Lumbar Spinal Stenosis, and with Axial Low Back Pain

Background: Functional status has been quantified in the adult low back pain (LBP) population, but has not been characterized for older adults with spinal symptoms. Objectives: To compare pain severity and functional status of older adults with and without spinal symptoms, and to determine what factors are associated with quality of life in the spinal stenosis and axial LBP groups. Methods: In 24 subjects greater than 55-years old with lumbar spinal stenosis, 12 with LBP, and 12 without spinal symptoms, obtain the following: pain severity with 10-cm visual analog scale (VAS), 15-minute walk test, 7-day walking distance, Quebec Back Pain Disability Scale (QBPDS), and Pain Disability Index (PDI). Results: The mean scores were worst for the stenosis group, were intermediate for the LBP group, and were the best for the asymptomatic group. Analysis of variance showed that the pain VAS (p < 0.001), 15-minute walk test (p = 0.01), 7-day walk (p = 0.02), QBPDS (p < 0.001), and PDI (p < 0.001) were different between at least two groups. All the variables in the stenosis group were worse than in the asymptomatic group, but only the pain VAS, QBPDS, and PDI in the LBP group were worse than in the asymptomatic group. In both the stenosis and LBP group the QBPDS and PDI were only related to pain VAS. Conclusion: Seniors with spinal stenosis and LBP have more disability than asymptomatic seniors. The 15-minute walking test with the stenosis group was slower than with the asymptomatic seniors. However, they compensate so that their 7-day walking distance is not as significantly decreased.

Specificity of needle electromyography for lumbar radiculopathy and plexopathy in 55- to 79-year-old asymptomatic subjects.

Tong HC, Haig AJ, Yamakawa KSJ, Miner JA: Specificity of Needle Electromyography for lumbar radiculopathy and plexopathy in 55- to 79-year-old asymptomatic subjects. Am J Phys Med Rehabil 2006;85:908–912. Objective:Determine specificity of needle electromyography for lumbar radiculopathy and plexopathy using a blinded study design. Design:Asymptomatic community volunteers ages 55 and older, as part of a spinal stenosis study, were given a standardized electrodiagnostic evaluation by a blinded electromyographer. A monopolar needle was used to evaluate five leg muscles and the lumbar paraspinal muscles. The specificities of different diagnostic criteria for radiculopathy and plexopathy were then calculated. Results:There were 30 subjects with a mean age of 65.4 yrs (SD 8.0). When only positive sharp waves or fibrillations were counted as abnormal, most of the diagnostic criteria (two limb muscles plus associated lumbar paraspinal muscle abnormal, two limb muscles abnormal, or one limb muscle plus associated lumbar paraspinal muscle abnormal) had 100% specificity. When we also included at least 30% polyphasia in the limb muscles as abnormal, the respective specificities were 97, 90, and 87%. When we also included at least 20% polyphasia in the limb muscles as abnormal, the respective specificities were 77, 60, and 60%. The specificity for plexopathy was 100% when only positive sharp waves or fibrillations were used, and it remained 100% when increased polyphasia was added. Conclusion:Needle electromyography has excellent specificity for lumbosacral radiculopathy and plexopathy when appropriate diagnostic criteria are used.

Paraspinal electromyography that compares concentric with monopolar needles: A blinded study

Tong HC, Young IA, Koch J, Haig AJ, Yamakawa KSJ, Wallbom A: Paraspinal electromyography that compares concentric with monopolar needles: A blinded study. Am J Phys Med Rehabil 2003;82:917–924. ObjectiveTo establish interrater reliability for paraspinal muscle needle electromyography study with both monopolar and concentric needles in symptomatic and asymptomatic persons and to further establish normative data for paraspinal needle study. DesignAt a university spine center, participants with and without radiating low back pain were evaluated with the mini–paraspinal mapping paraspinal needle technique by an unblinded and a blinded electromyographer. ResultsIn the symptomatic group, the intraclass correlation coefficient between concentric and monopolar needles was 0.793; between monopolar needles, it was 0.876; and between concentric needles, it was 0.966. In the asymptomatic group, the mean total score was 0.25. ConclusionsThe good interrater reliability with the same needle type helps support the validity of the needle electromyography study of the paraspinal muscles. The good correlation between the concentric and monopolar needles shows the data published using monopolar needle data also apply to studies using paraspinal needle electromyography with concentric needles. The low score with the asymptomatic group reaffirms that using a cutoff score of >2 as abnormal has a false-positive rate of <5%.

Magnetic resonance imaging of the lumbar spine in asymptomatic older adults

Asymptomatic subjects greater than 55 years old received lumbar spine magnetic resonance imaging studies. Two radiologists, blinded to the subjects’ history, independently read the scans for the presence of abnormalities. One radiologist also measured spinal canal dimensions. In 33 subjects, at least one disc bulge was present in 28 (84.8%) subjects, at least one disc herniation in 6 (18.2%), at least one degenerated facet joint in 25 (75.7%), ligamentous thickening in 22 (66.7%), and anterolisthesis in 6 (18.2%). Twenty-four (68.5%) had at least mild, 10 (28.6%) had at least moderate, and 2 (5.6%) had severe central canal stenosis. Mean osseous spinal canal diameter gradually decreased from 20.4 mm at the L1-2 level to 16.0 mm at L5-S1. Midline thecal sac diameter and lateral recess anterior-posterior diameter were relatively unchanged. Interfacet distances both slowly increased from L1-2 to L5-S1. To achieve 95% and 90% specificities, the lower-limit cutoff should be 10.7 mm and 11.9 mm for the osseous spinal canal diameter, 6.5 mm and 7.6 mm for the thecal sac, and 3.7 mm and 4.3 mm for the lateral recess. Understanding the range of findings in asymptomatic older subjects will help clinicians better treat older patients with spinal disorders.

Paraspinal electromyography: age-correlated normative values in asymptomatic subjects.

Study Design. Cross-sectional study. Objectives. To determine if the amount of lumbar paraspinal denervation increases with age and present normative data on the amount of denervation present in asymptomatic subjects. Summary of Background Data. To our knowledge, there are no data on the relationship of paraspinal denervation with age or normative data on the amount of denervation expected in asymptomatic older adults. Methods. We combined the data from our current study of asymptomatic adults, age 55–79 years, and a previous study of asymptomatic adults, age 18–58 years, who underwent lumbar paraspinal muscle needle electromyography using a validated needle electromyography (MiniPM) technique. We then compared the results of the age group 55–79 to that of the age group 18–54. Results. The older group scored significantly higher than the younger group by 1.7 (P = 0.008, 95% confidence interval 0.5–3.0). Linear regression showed that age was a significant predictor of the MiniPM score (β = 0.04, and P = 0.04). For subjects 55 years and older, mean MiniPM score on one side was 2.3 (standard deviation 3.6). The upper range of the 95th percentile was 10. Conclusions. The amount of lumbar paraspinal muscle denervation does increase with age. Understanding the range of findings in asymptomatic subjects will help us interpret lumbar paraspinal needle electromyography findings in patients with spinal disorders.