Karen Yamakawa

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.

Relationship between ambulation and obesity in older persons with and without low back pain

CONTEXT: For obese older persons, ambulation is both functionally important and a means of weight control. The relationship between weight and ambulation is not known in this population. Also, the extent to which pain interferes with ambulation is not studied.OBJECTIVE: To examine the relationship between obesity and ambulation, and to determine the effect of pain and body mass index (BMI) on ambulation in older persons.DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of 82 older persons, ages 55–79 y, some with no back pain recruited from the community, others with back pain or spinal stenosis recruited from a magnetic resonance imaging (MRI) scanner as part of a larger university study of spinal stenosis.OUTCOME MEASURES: Age, Visual Analog Scales for pain, BMI, patient diagnosis (no pain, mechanical back pain, and spinal stenosis), walking velocity and stride length on a 15-min laboratory ambulation test, and 1-week community ambulation measured with a pedometer (steps, distance, and energy expenditure).RESULTS: BMI had a significant inverse relationship with ambulatory measurements in terms of the distance walked, steps taken, and walking velocity. Pain severity and pain category also had a significant inverse relationship with these measures. A negative correlation was observed between pain and obesity, although the relationship was statistically nonsignificant.DISCUSSION: Obese older people walked less than the nonobese older people. Pain was associated with decreased ambulation. Clinicians who intend to encourage increased ambulation in older obese persons should consider possible barriers posed by musculoskeletal pain.

The relation among spinal geometry on MRI, paraspinal electromyographic abnormalities, and age in persons referred for electrodiagnostic testing of low back symptoms.

Study Design. A retrospective EMG study with blinded radiologic measurement was conducted. Objective. To determine the relation among spinal measurements on MRI, paraspinal denervation, and age in patients referred for electrodiagnostic and radiologic evaluation of low back pain. Summary of Background Data. Spinal pathology, including disc herniation and spinal stenosis, can cause denervation of the paraspinal muscles. Various mechanisms including direct compression, inflammation, vascular compromise, and mechanical stretch of the posterior primary ramus may play a role in denervation. The relation between the amount of denervation and the size of the spinal canal can assist in understanding the pathophysiology of back pain. Since paraspinal denervation may increase with age in asymptomatic persons, age is an important covariable. Methods. At a university hospital, 44 patients referred to undergo both electrodiagnostic evaluation and MRI for low back pain were studied. The study investigated the relation among the following: 1) axial MRI spinal measurements (canal transverse diameter, anteroposterior diameter, and area; thecal sac anteroposterior diameter and area; and the radiologist’s overall impression at each level) and denervation measurements in terms of scores on the MiniPM, a quantified needle electromyographic measure of paraspinal denervation; 2) various models of multilevel spinal compression (smallest, smallest two, and average spinal levels for each measurement) and MiniPM scores; and 3) MRI spinal canal measurements and age. Results. Although individual MRI measurements and combinations of measurements did not relate to MiniPM scores, the radiologist’s impression was significantly related. The “smallest two” levels measurement had the strongest relation (r = 0.400;P < 0.007). Age related to the MiniPM scores (P = 0.004) and radiologic impression (P = 0.031). A regression suggested that MiniPM was an independent predictor of age. Conclusions. The radiologist’s overall impression is more accurate than axial image measurements in predicting paraspinal denervation. A combination score of the smallest two levels is the most accurate, perhaps relating to the vascular pathophysiology of stenosis. There is more denervation with increasing age in this symptomatic population.

Predictors of Walking Performance and Walking Capacity in People with Lumbar Spinal Stenosis, Low Back Pain and Asymptomatic Controls

OBJECTIVE To examine predictors of community walking performance and walking capacity in people with lumbar spinal stenosis (LSS), compared with people with low back pain and asymptomatic control subjects. DESIGN Retrospective analysis. SETTING University spine program. PARTICIPANTS Participants (N=126; 50 LSS, 44 low back pain, 32 asymptomatic control subjects) aged 55 to 80 years were studied. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Seven-day community walking distance measured by pedometer (walking performance) and a 15-minute walking test (walking capacity). All participants had lumbosacral magnetic resonance imaging, electrodiagnostic testing, and a history and physical examination, including a history of pain and neurologic symptoms, a straight leg raise test, and tests for directional symptoms, reflexes, strength, and nerve tension signs. The study questionnaire included demographic information, a history of back/leg pain, and questions about walking, exercise frequency, and pain level, as well as the standardized Quebec Back Pain Disability Scale. RESULTS Body mass index (BMI), pain, age, and female sex predicted walking performance (r(2)=.41) and walking capacity (r(2)=.41). The diagnosis of LSS itself had no clear relationship with either walking variable. Compared with the asymptomatic group, LSS participants had significantly lower values for all walking parameters, with the exception of stride length, while there was no significant difference between the LSS and low back pain groups. CONCLUSIONS BMI, pain, female sex, and age predict walking performance and capacity in people with LSS, those with low back pain, and asymptomatic control subjects. While pain was the strongest predictor of walking capacity, BMI was the strongest predictor of walking performance. Average pain, rather than leg pain, was predictive of walking performance and capacity. Obesity and pain are modifiable predictors of walking deficits that could be targets for future intervention studies aimed at increasing walking performance and capacity in both the low back pain and LSS populations.

Magnetic resonance imaging vs. electrodiagnostic root compromise in lumbar spinal stenosis: a masked controlled study.

Chiodo A, Haig AJ, Yamakawa KSJ, Quint D, Tong, H, Choksi VR: Magnetic resonance imaging vs. electrodiagnostic root compromise in lumbar spinal stenosis: a masked controlled study. Objective:The high false-positive rate of magnetic resonance imaging (MRI) makes it a less-than-reliable tool for evaluating clinically significant stenosis. Finding MRI changes that correlate with electrodiagnostic abnormalities might lead to more successful treatment decision making. The purpose of this study was to identify MRI changes that correlate with neurologic abnormalities measured by electrodiagnosis in patients with spinal stenosis. Design:One hundred fifty persons with and without back pain between the ages of 55 and 79 yrs participated in this prospective, blinded, controlled study. Exclusion criteria included previous spine surgery or known neuropathy. Needle electromyography of the limb, nerve conduction studies, including peroneal F-wave and tibial H-wave, and noncontrast lumbo-sacral spine MRI were completed. A codified physical medicine and rehabilitation history and physical examination was completed to differentiate symptomatic lumbar stenosis patients from asymptomatic controls. The relationship between lumbar MRI measurements and extremity electromyography findings was studied. Results:MRI measurements did not differ significantly with respect to extremity needle electromyography findings in the entire population or in patients with clinical signs of lumbar stenosis. In the entire population, an absent tibial H-wave corresponded to the interfacet ligament distance at L5–S1 and anterior to posterior canal size at L4–5. In patients clinically evaluated as having lumbar stenosis, peroneal F-wave latency correlated with anteroposterior canal size at L4–5 and interfacet ligament and anterior to posterior lateral recess narrowing at L5–S1. In patients with clinical signs and symptoms of lumbar stenosis, limb electromyography findings did not correlate with MRI measurements, although H-wave and F-wave testing correlated with relevant locations of stenosis. Conclusions:Needle electromyography does not differentiate patients with symptomatic mild or moderate lumbar stenosis. However, H-wave and F-wave correlated to specific anatomical changes on MRI in this patient population.

Functional Capacity Evaluations in Persons With Spinal Disorders: Predicting Poor Outcomes on the Functional Assessment Screening Test (FAST)

This study determines how performance on the simple, low exertion Functional Assessment Screening Test (FAST) relates to performance on more extensive physical and psychological testing. One hundred eighty-eight persons with chronic back disability and 17 spine healthy volunteers underwent the FAST (three 2-min static tests [kneeling, stooping, and squatting] and two 5-min tests [repetitive stooping and repetitive twisting while standing]), the Progressive Isoinertial Lifting Evaluation (PILE), trunk extension endurance, submaximal bicycle ergometry, and psychological profiles. All FAST components were completed by 88% of spine healthy subjects, but only by 19.7% (n = 37) of the back patients. Internal consistency for overall test performance was 0.82 (alpha coefficient). Back pain noncompleters had poorer performance on the PILE and trunk extension endurance despite similar cardiovascular fitness and perceived exertion during testing. They had more dysfunctional coping mechanisms, pain avoidance, depression, and self-reported disability. Since performance on nonstrenuous testing is so poor, and psychosocial variables relate strongly to test performance, extensive Functional Capacity Evaluations may not be necessary or valid in assessing the physical performance of this population of chronic back pain patients.