Jennifer A. Miner

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.

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.

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.

Health-related quality of life in caregivers of individuals with traumatic brain injury: Development of a conceptual model

OBJECTIVES To identify aspects of health-related quality of life (HRQOL) that are relevant to caregivers of individuals with traumatic brain injury (TBI) and to propose an integrated conceptual framework based on this information. DESIGN Nine focus groups with caregivers of individuals with moderate-to-severe TBI were qualitatively analyzed to ascertain the effect that caring for an individual with a TBI has on caregiver HRQOL. SETTING University hospitals and rehabilitation treatment centers. PARTICIPANTS Caregivers (N=55) of individuals with moderate-to-severe TBI. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Not applicable. RESULTS Qualitative analysis indicated that caregivers were most concerned about their social health (42% of comments). Other important issues were emotional health (34%), physical health (11%), cognitive health (3%), and feelings of loss (9%; feelings of loss related to changes in the future/potential of the care recipient or related to the caregiver). Areas of concern that were discussed that were specific to the caregiver and not fully evaluated by existing patient-reported outcomes (PROs) included feelings of loss, anxiety related to the caregiver role (reinjury concerns, worry about leaving the person alone, etc), and caregiver strain (burden, stress, feeling overwhelmed, etc). CONCLUSIONS Although existing PROs capture relevant aspects of HRQOL for caregivers, there are HRQOL domains that are not addressed. A validated and sensitive HRQOL tool for caregivers of individuals with TBI will facilitate initiatives to improve outcomes in this underserved group.

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.