This is an evidence-based review of electrodiagnostic (EDX) testing of patients with suspected lumbosacral radiculopathy to determine its utility in diagnosis and prognosis. Literature searches were performed to identify articles applying EDX techniques to patients with suspected lumbosacral radiculopathy. From the 355 articles initially discovered, 119 articles describing nerve conduction studies, electromyography (EMG), or evoked potentials in adequate detail were reviewed further. Fifty-three studies met inclusion criteria and were graded using predetermined criteria for classification of evidence for diagnostic studies. Two class II, 7 class III, and 34 class IV studies described the diagnostic use of EDX. One class II and three class III articles described H-reflexes with acceptable statistical significance for use in the diagnosis and confirmation of suspected S1 lumbosacral radiculopathy. Two class II and two class III studies demonstrated a range of sensitivities for use of muscle paraspinal mapping. Two class II studies demonstrated the utility of peripheral myotomal limb electromyography in radiculopathies.

Yagci I, Gunduz OH, Ekinci G, Diracoglu D, Us O, Akyuz G: The utility of lumbar paraspinal mapping in the diagnosis of lumbar spinal stenosis. OBJECTIVE:: The aim of this prospective, blinded and controlled study is to evaluate the utility of lumbar paraspinal mapping in the diagnosis of lumbar spinal stenosis. DESIGN:: The subjects were assessed and allocated into three groups according to clinical and radiologic features with a standardized assessment protocol. These three groups were clinical and radiologic lumbar spinal stenosis, radiologic lumbar spinal stenosis, and the control group. The measurements of magnetic resonance imaging studies were performed by a blinded radiologist. An electromyographer who was masked to patients' data performed all the nerve conduction tests, lower-limb needle electromyography, and lumbar paraspinal mapping. The relations of clinical, radiologic, and electrophysiologic findings were investigated. RESULTS:: Sixty-two patients were enrolled in the study. Two patients were eliminated because electrophysiologic studies showed polyneuropathy. There were 28, 16, and 16 patients in clinical and radiologic lumbar spinal stenosis, radiologic lumbar spinal stenosis, and control groups, respectively. In the clinical and radiologic lumbar spinal stenosis group, the findings of limb needle electromyography were inconsistent with 50% acute and 46.4% chronic radiculopathy. However, the paraspinal mapping showed that there were fibrillation potentials and positive sharp waves in at least two levels in 92.8% of the patients in clinical and radiologic lumbar spinal stenosis. The mean total paraspinal mapping score was 33.64 +/- 21.17, which was significantly higher than the radiologic lumbar spinal stenosis and control groups. In the radiologic lumbar spinal stenosis group, the findings of paraspinal mapping were normal in 93.8% of the patients. Paraspinal mapping technique was found to be better correlated to the clinical findings than magnetic resonance imaging in asymptomatic patients. In the control group, 6 of 14 patients had high total paraspinal mapping scores (range, 0-9). Those patients with higher paraspinal mapping scores in the control group were mostly diagnosed with acute monoradiculopathy caused by disc herniation. CONCLUSIONS:: Paraspinal mapping technique is a sensitive method in the diagnosis of lumbar spinal stenosis and reflects physiology of nerve roots better than the limb electromyography.

OBJECTIVES To describe neurophysiologic changes over time in persons with and without spinal complaints and to assess whether paraspinal denervation predicts change in stenosis on magnetic resonance imaging (MRI) and clinical course. DESIGN Prospective, controlled, masked trial. SETTING University spine program. PARTICIPANTS Persons aged 55 to 80 years, screened for polyneuropathy and determined on clinical examination to have spinal stenosis, mechanical low back pain, or no spinal symptoms. INTERVENTIONS A comprehensive codified history was obtained and subjects underwent physical examination, ambulation testing, masked electrodiagnostic testing including paraspinal mapping, and MRI, repeated at greater than 18 months. This study presents detailed technical information and additional analyses not reported previously. MAIN OUTCOME MEASUREMENTS Change in electrodiagnostic findings. Among persons with clinical stenosis, relationship of change in paraspinal mapping scores to MRI findings and clinical changes. RESULTS Of 149 initial subjects, 83 (79.3% of eligible subjects) repeated testing at 20 (+/-2 SDs) months. No significant change in limb muscle spontaneous activity or motor unit pathology was noted in any group. In 23 persons with initial diagnosis of stenosis, paraspinal mapping electromyography related to change in diagnosis over time (analysis of variance F = 3.77, P =.037), but not to most initial magnetic resonance imaging measurements or to change in spinal canal diameter. CONCLUSIONS Clinical spinal stenosis is neurophysiologically stable in most persons. Paraspinal electromyographic changes reflect large changes in clinical course, but neither neurophysiologic nor clinical changes relate to change in spinal geometry over 20 months.

We present a literature review of the diagnosis and treatment of acquired lumbar spinal stenosis (LS), with a brief description of new surgical techniques. LS is the most common cause of spinal surgery in individuals older than 65 years of age. Neurogenic claudication and radiculopathy result from compression of the cauda equina and lumbosacral nerve roots by degenerated spinal elements. Surgical decompression is a well established treatment for patients with refractory, or moderate to severe clinical symptoms. However, the variety of surgical options is vast. New techniques have been developed with the goal of increasing long term functional outcomes. In this article we review lumbar decompression and fusion as treatment options for LS but also present other recent developments. Prospective long term studies are necessary to know which procedures would result in optimal patient outcome.

OBJECT The aim of this retrospective study was to evaluate the clinical usefulness of assessing lumbar somatosensory evoked potentials (SSEPs) in central lumbar spinal stenosis (LSS). METHODS The latencies of lumbar SSEPs were recorded in 40 patients with central LSS, including 16 men and 24 women. The mean age of the patients was 67.3 +/- 7.4 years. The diagnosis was LSS in 23 cases and LSS associated with degenerative spondylolisthesis in 17 cases. The average duration of symptoms was 43.8 +/- 51.2 months. Twenty-two cases had bilateral and 18 cases had unilateral leg symptoms. Thirty-seven cases were associated with neurogenic intermittent claudication and the mean walking distance of patients with this condition was 246.8 +/- 232.7 m. The mean Japanese Orthopedic Association scale score, as well as the visual analog scale (VAS) scores of low-back pain, leg pain, and numbness, were 16.5 +/- 3.5, 6.0 +/- 2.5, 6.9 +/- 2.1, and 7.8 +/- 2.2, respectively. The minimal cross-sectional area of the dural sac on MR imaging was 0.44 +/- 0.21 cm(2). Thirty-nine cases of cervical spondylotic myelopathy without lumbar and peripheral neuropathy were chosen as the control group. RESULTS The latencies of lumbar SSEPs in patients with LSS and in the control group were 23.0 +/- 2.0 ms and 21.6 +/- 1.9 ms, respectively. There was a statistically significant difference between the LSS and control groups (p < 0.05). The latency of lumbar SSEPs was significant correlated with the VAS score of leg numbness (p < 0.05). The latency of lumbar SSEPs in LSS was clearly delayed when the VAS score of leg numbness was > or = 8 (p < 0.05). CONCLUSIONS Lumbar SSEPs are able to detect neurological deficit in the lumbar area effectively, and they can reflect part of the subjective severity of sensory disturbance (numbness) in LSS. Both lumbar SSEPs and VAS scores of leg numbness may be useful for clinical evaluation in patients with LSS.

OBJECTIVE This study compares Routine nerve conductions studies (NCS)/needle electromyography (nEMG) with a multiparameter recording method (NC-stat; NeuroMetrix Inc., Waltham, MA, USA) in patients with lumbosacral radiculopathies (LSR). METHODS Charts from 34 consecutive patients with a clinical history and/or examination consistent with an LSR were retrospectively reviewed. All underwent both Routine NCS/nEMG studies and NC-stat EDX. NC-stat testing included peroneal and posterior tibial nerve distal motor latencies and amplitudes and F-wave analysis. Twenty-eight patients had magnetic resonance imaging of the lumbosacral spine, and two had post-myelogram computerized tomography scan. RESULTS In the 24 patients with abnormal routine NCS/nEMG, NC-stat EDX was abnormal in 22. Raw agreement values between specific abnormal Routine and NC-stat EDX parameters ranged from 065 to 0.76. NC-stat amplitude and F-wave data provide reasonable electrodiagnostic 'rule in, rule out' information for LSR. Routine and NC-stat EDX had comparable positive and negative likelihood ratios with radiographic findings based on blinded neuroradiological evaluation. This included good 'stand alone' values for NC-stat F-wave and compound muscle action potential (CMAP) amplitude abnormalities in patients with spinal stenosis. CONCLUSIONS This report supports the value of multiparameter clinical neurophysiological evaluations in patients with LSR including CMAPs and F-waves.

OBJECTIVE Clinical 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. DESIGN Cross-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. RESULTS Using 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. CONCLUSIONS AP 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.

BACKGROUND CONTEXT: Degenerative de novo scoliosis is commonly present in older adult patients with spinal pain. The degenerative process including disc bulging, facet arthritis, and ligamentum flavum hypertrophy contributes to the appearance of symptoms of spinal stenosis in these patients. PURPOSE: The etiology, prevalence, biomechanics, classification, symptomatology, and treatment of degenerative lumbar scoliosis in association with spinal stenosis are reviewed. STUDY DESIGN: Review study. METHODS: Retrospective analysis of studies focused on all parameters concerning degenerative scoliosis associated with stenosis. RESULTS: There is a variety of treatment methods of degenerative scoliosis based on symptomatology and radiologic measurements of scoliosis and stenosis. Satisfactory clinical results reported in relevant retrospective studies after operative treatment range from 83% to 96% but with increased percentage of complications. An algorithm for operative treatment corresponding to a newly proposed classification system of degenerative lumbar scoliosis with associated canal stenosis is presented. CONCLUSIONS: There is an increasing prevalence of degenerative scoliosis in the aged population. Even though the exact percentage of patients with symptomatology of spinal stenosis is not known, the main goal is to provide pain relief and improved functional lifestyle with minimum intervention.

OBJECTIVE To examine the impact of clinician factors on technical data within an electrodiagnostic consultation for low-back pain and spinal stenosis. DESIGN Examiner differences on single-segment paraspinal mapping scores and other findings were examined in a prospective, masked, double-controlled trial involving 150 people aged 55-80 yrs who were selected for no symptoms, back pain, or possible spinal stenosis. RESULTS Unmasked clinicians were more variable than masked physicians (F2,219 = 4.808, P =or<0.01) and gave lower scores to people they felt had mechanical back pain. The percentage of inadequate segmental scores differed among clinicians (0-16.6%, F8,226 = 4.170, P < 0.001), with fellows having more difficulty than faculty (11.76 +/- 32.38% vs. 0.75 +/- 8.67%)(t233 = 3.753, P < 0.001). Correction of clinician bias improved the relationship between paraspinal score and subjects' ability to walk (weighted regression R = 0.129, B =-0.047, P < 0.001; unweighted regression R = 0.090, B =-0.045, P < 0.001). CONCLUSIONS Objective testing is adversely affected by clinician factors including prejudgment, experience, and individual idiosyncrasies. Less variation is found in more codified procedures. For electrodiagnostic consultation, correction of variability improves the relationship of test results to disability.

The objective of this study was to investigate the relationship between electrophysiological recordings and clinical as well as radiological findings in patients suggestive to suffer from a lumbar spinal stenosis (LSS). We hypothesise that the electrophysiological recordings, especially SSEP, indicate a lumbar nerve involvement that is complementary to the neurological examination and can provide confirmatory information in less obvious clinical cases. In a prospective cohort study, 54 patients scheduled for surgery due to LSS were enrolled in an unmasked, uncontrolled trial. All patients were assessed by neurological examination, electrophysiological recordings, and magnetic resonance imaging (MRI) of the lumbar spine. The electrophysiological recordings focused on spinal lumbar nerve involvement. Results About 88% suffered from a multisegmental LSS and 91% of patients respectively complained of chronic lower back pain and/or leg pain for more than 3 months, combined with a restriction in walking distance. The neurological examination revealed only a few patients with sensory and/or motor deficits while 87% of patients showed pathological electrophysiological recordings (abnormal tibial SSEP in 78% of patients, abnormal H-reflex in 52% of patients). Conclusions Whereas the clinical examination, even in severe LSS, showed no specific sensory-motor deficit, the electrophysiological recordings indicated that the majority of patients had a neurogenic disorder within the lumbar spine. By the pattern of bilateral pathological tibial SSEP and pathological reflexes associated with normal peripheral nerve conduction, LSS can be separated from a demyelinating polyneuropathy and mono-radiculopathy. The applied electrophysiological recordings, especially SSEP, can confirm a neurogenic claudication due to cauda equina involvement and help to differentiate neurogenic from vascular claudication or musculo-skeletal disorders of the lower limbs. Therefore, electrophysiological recordings provide additional information to the neurological examination when the clinical relevance of a radiologically-suspected LSS needs to be confirmed.

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 physician's diagnosis of clinical spinal stenosis was significantly related to the neurological findings on examination (p < 0.05) and to the spine surgeon's 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.

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.

OBJECTIVE To assess the relations between clinically recognized lumbar spinal stenosis and the conclusions of masked radiologists and electrodiagnosticians. DESIGN Prospective, masked, double-controlled trial. SETTING University spine center. PARTICIPANTS One hundred fifty persons age 55 to 80 years with or without back pain and with or without magnetic resonance imaging (MRI)-demonstrated stenosis, screened for neuropathy risk, previous surgery, or cancer. INTERVENTIONS Questionnaires on pain and function; ambulation testing and physical examination; and masked electrodiagnotics and MRI. MAIN OUTCOME MEASURE Diagnostic impressions of the examining clinician, radiologist, and electrodiagnostician. RESULTS Following application of post hoc exclusion criteria and elimination of patients due to incomplete or inadequate test data, the clinical diagnosis was lumbar stenosis in 50 subjects, back pain in 44 subjects, and no pain in 32 subjects. Radiologic and clinical impression had no relation (P =.80 vs asymptomatic, P =.99 vs back pain controls). Electrodiagnostic impression trended to relate to clinical impression (P =.14 vs asymptomatic, P =.09 vs back pain). Retrospective application of age-related electrodiagnostic norms for paraspinal electromyographic and limb motor unit changes, established in this study, reclassified 13 of the 17 asymptomatic persons whom the electrodiagnostician thought had stenosis. The clinical impression did correspond to history and physical examination findings typically associated with spinal stenosis and to the independent impression of a neurosurgeon who examined MRI and clinical, but not to the electrodiagnostic data. CONCLUSIONS The impression obtained from an MRI scan does not determine whether lumbar stenosis is a cause of pain. Electrodiagnostic consultation may be useful, especially if age-related norms obtained in this study are applied.

OBJECTIVE Clinical 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. DESIGN Cross-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. RESULTS Using 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. CONCLUSIONS AP 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.

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.

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.

OBJECTIVE False positive imaging tests--disk herniation or spinal stenosis--occur in a significant number of asymptomatic persons, increasing with age. A similar or greater prevalence probably occurs in people who present to physicians with mechanical back pain, potentially causing therapeutic misadventure. Electrodiagnostic testing may be normal in persons with asymptomatic pathology, but has not been directly tested. METHODS As part of a larger study of older persons with lumbar stenosis, 35 asymptomatic adults were evaluated by an extensive questionnaire, codified history and physical examination, masked electrodiagnostic testing, and masked lumbar magnetic resonance imaging, with repeated procedure at 18 months. Thirty-two subjects remained after removal of three with neuromuscular disease. RESULTS The radiologist characterized 18 (56%) asymptomatic subjects as having spinal stenosis. There was no relationship between electrodiagnostician diagnosis and radiologist diagnoses. Among the 13 whom the electrodiagnostician identified as abnormal, 2 had technical data within normal limits and the only abnormality in 5 was >2/10 polyphasic motor units (considered a 'soft' finding by many). One muscle in 1 subject had abnormal spontaneous activity, and 3 persons scored >4 on paraspinal mapping. Electrodiagnostic findings were normal in the 5 (16%) who had disk herniations. None of the 22 re-examined acquired symptoms over 18 months and follow-up electrodiagnosis was essentially normal (one muscle in 1 subject had 3/10 polyphasic motor units). CONCLUSIONS MRI changes, motor unit changes on EMG needle examination, and low paraspinal mapping scores are not uncommon in asymptomatic older adults with spinal stenosis or disk herniation and may lead to false positive tests. The stricter criterion of abnormal spontaneous activity on needle examination and paraspinal mapping scores greater than 6 offered in this paper lowers the risk of false positive EMG testing. SIGNIFICANCE EMG is less likely to be abnormal (false positive) in asymptomatic adults than MRI.

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.

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 (beta = 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.

BACKGROUND CONTEXT Previous studies on epidural injections have focused on efficacy and have not evaluated factors predicting outcomes of epidural injections. PURPOSE To determine which patient factors are associated with transforaminal epidural injection outcomes for sciatica. STUDY DESIGN Cross-sectional study design at a university spine center. PATIENT SAMPLE Consecutive patients with sciatica who have had an electromyography study and a transforaminal epidural injection between January 1999 and July 2001. OUTCOME VARIABLE The outcome variable was a composite score of the patients' pain severity and medication use compared with their initial visit. Independent variables included demographics, previous back surgery, pain severity at initial presentation, pain medication use at initial presentation, litigation, having Social Security Disability Insurance (SSDI) or workers' compensation, electromyography results. METHODS Medical information was gathered on the variables listed above. RESULTS Seventy-six patients, mean age 50.4 years and 49% female, participated. At a mean follow-up of 122 days (SD 146.3), 35 (47%) were improved, 21 (28% were unchanged) and 12 (16%) were worse. Initial correlation analysis showed some relationship between outcomes and having SSDI or workers' compensation (R=.43, p<.001), lifting requirements at work (R=.44, p=.002), working status (R=-.31, p=.02), and electromyogram evidence of radiculopathy (R=-.25, p=.04). Regression analysis showed that having SSDI or workers' compensation was the primary factor associated with worse outcomes. CONCLUSIONS When controlled for SSDI/workers' compensation, lifting requirements at work, but not working status and radiculopathy, also were associated with outcomes but the association was not as strong. This paper brings into question the utility of offering epidural injections to patients who are on SSDI/workers' compensation and require heavy lifting at work.

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.

OBJECTIVE To examine the relationship between ligamentum flavum thickness and clinical spinal stenosis. DESIGN A validation study. SETTING Clinical research laboratory. PATIENTS A total of 119 subjects from the Michigan Spinal Stenosis Study (MSSS). METHODS Two new measurement techniques were compared by use of magnetic resonance images of 4 asymptomatic subjects by 2 examiners. The technique with the best interrater reliability was then used to measure the ligamentum flavum at L4-L5 in 119 subjects in the MSSS who, on the basis of clinical examination without imaging, were thought to have lumbar stenosis, mechanical back pain, or no pain. These findings were related to other radiologic findings, demographics, clinical severity, and electrodiagnostic findings. MAIN OUTCOME MEASUREMENTS Perpendicular on the inside of the spinal canal from the deepest point of concavity of the lamina to the edge of the ligament. RESULTS The ligamentum flavum width measurement had high interrater (r = 0.774) and intrarater (r = 0.768) reliability. In 28 asymptomatic volunteers, ligamentum flavum width averaged 5.72 ± 0.95 mm, with the left side significantly thinner than the right (t = 2.117, P =.044), and thicker ligaments with age (r = 0.653, P <.001). Asymptomatic persons whom radiologists thought had stenosis had thicker ligaments (t = 2.273, P =.032). Persons with clinical stenosis (n = 48) and mechanical pain (n = 43) had ligament thickness similar to that of asymptomatic volunteers. Among patients with clinical stenosis, ligamentum flavum thickness did not relate to symptom severity (pedometer and laboratory ambulation tests, Pain Disability Index, and visual analog scale for pain). Most neurophysiological findings had no relationship with ligamentum flavum width, except the presence of limb fibrillation potentials related to a thinner ligament (t = 2.915, P =.004). CONCLUSIONS The measurement technique is standardized for the ligamentum flavum for future use. Although the ligamentum flavum appears to get thicker with age, other factors, including clinical diagnosis, pain, and function, do not appear to relate to the ligamentum flavum width.

OBJECTIVE The aim of this study was to determine the specificity of needle electromyography for lumbar radiculopathy in subjects with low back pain and sciatica without stenosis. DESIGN Subjects 55 yrs or older with diagnoses of low back pain and sciatica underwent a standardized monopolar needle evaluation by blinded electromyographers as part of a spinal stenosis study. The presence or absence of radiculopathy was determined using different electrodiagnostic criteria. RESULTS Seventy-two subjects with a mean age of 64.6 yrs (SD, 7.0 yrs) were studied. When only positive sharp waves or fibrillations were considered abnormal, most of the diagnostic criteria (two limb muscles and associated lumbar paraspinal muscle abnormal, two limb muscles abnormal, or one limb muscle and associated lumbar paraspinal muscle abnormal) had 100% specificity. When 30% or greater polyphasia in the limb muscles was also considered abnormal, the respective specificities were 97%, 90%, and 87%. When 20% or greater polyphasia in the limb muscles was also considered abnormal, the respective specificities were 77%, 60%, and 60%. CONCLUSIONS There is good specificity for lumbosacral radiculopathy when appropriate diagnostic criteria are used.

OBJECTIVE: To report on 9 patients presenting with sporadic motor neuron disease , who over a long period of time evolved with a symmetrical proximal brachial amyotrophic diplegia. METHODS: Nine patients were followed-up who , displayed, since onset, a progressive limitation of arm flexion/abduction resulting in a peculiar posture with both hands hanging loosely beside the trunk. Electrophysiological test results were consistent with lower motor neuron disease. Cervical MRI was performed in all patients. RESULTS: Nine male subjects with ages ranging from 38 to 73 years at onset of symptoms, developed bilateral and symmetric paresis and atrophy of upper limb muscles. Proximal muscles were more involved than the distal groups. In most patients tendon reflexes were absent or hypoactive in the upper limbs. Needle electromyography (EMG) revealed positive sharp waves and fibrillations and high amplitude polyphasic potentials with an incomplete recruitment pattern in most upper limb muscles. EMG of lower limb muscles was normal in some cases while abnormal in others. MRC did not disclose cervical spinal cord abnormalities from C5-T1. CONCLUSION: Attention is called to the Man-in-the-Barrel syndrome in some motor neuron diseases, especially in patients with progressive spinal atrophy and amyotrophic lateral sclerosis.

Yagci I, Gunduz OH, Ekinci G, Diracoglu D, Us O, Akyuz G: The utility of lumbar paraspinal mapping in the diagnosis of lumbar spinal stenosis. OBJECTIVE:: The aim of this prospective, blinded and controlled study is to evaluate the utility of lumbar paraspinal mapping in the diagnosis of lumbar spinal stenosis. DESIGN:: The subjects were assessed and allocated into three groups according to clinical and radiologic features with a standardized assessment protocol. These three groups were clinical and radiologic lumbar spinal stenosis, radiologic lumbar spinal stenosis, and the control group. The measurements of magnetic resonance imaging studies were performed by a blinded radiologist. An electromyographer who was masked to patients' data performed all the nerve conduction tests, lower-limb needle electromyography, and lumbar paraspinal mapping. The relations of clinical, radiologic, and electrophysiologic findings were investigated. RESULTS:: Sixty-two patients were enrolled in the study. Two patients were eliminated because electrophysiologic studies showed polyneuropathy. There were 28, 16, and 16 patients in clinical and radiologic lumbar spinal stenosis, radiologic lumbar spinal stenosis, and control groups, respectively. In the clinical and radiologic lumbar spinal stenosis group, the findings of limb needle electromyography were inconsistent with 50% acute and 46.4% chronic radiculopathy. However, the paraspinal mapping showed that there were fibrillation potentials and positive sharp waves in at least two levels in 92.8% of the patients in clinical and radiologic lumbar spinal stenosis. The mean total paraspinal mapping score was 33.64 +/- 21.17, which was significantly higher than the radiologic lumbar spinal stenosis and control groups. In the radiologic lumbar spinal stenosis group, the findings of paraspinal mapping were normal in 93.8% of the patients. Paraspinal mapping technique was found to be better correlated to the clinical findings than magnetic resonance imaging in asymptomatic patients. In the control group, 6 of 14 patients had high total paraspinal mapping scores (range, 0-9). Those patients with higher paraspinal mapping scores in the control group were mostly diagnosed with acute monoradiculopathy caused by disc herniation. CONCLUSIONS:: Paraspinal mapping technique is a sensitive method in the diagnosis of lumbar spinal stenosis and reflects physiology of nerve roots better than the limb electromyography.

OBJECTIVE False positive imaging tests--disk herniation or spinal stenosis--occur in a significant number of asymptomatic persons, increasing with age. A similar or greater prevalence probably occurs in people who present to physicians with mechanical back pain, potentially causing therapeutic misadventure. Electrodiagnostic testing may be normal in persons with asymptomatic pathology, but has not been directly tested. METHODS As part of a larger study of older persons with lumbar stenosis, 35 asymptomatic adults were evaluated by an extensive questionnaire, codified history and physical examination, masked electrodiagnostic testing, and masked lumbar magnetic resonance imaging, with repeated procedure at 18 months. Thirty-two subjects remained after removal of three with neuromuscular disease. RESULTS The radiologist characterized 18 (56%) asymptomatic subjects as having spinal stenosis. There was no relationship between electrodiagnostician diagnosis and radiologist diagnoses. Among the 13 whom the electrodiagnostician identified as abnormal, 2 had technical data within normal limits and the only abnormality in 5 was >2/10 polyphasic motor units (considered a 'soft' finding by many). One muscle in 1 subject had abnormal spontaneous activity, and 3 persons scored >4 on paraspinal mapping. Electrodiagnostic findings were normal in the 5 (16%) who had disk herniations. None of the 22 re-examined acquired symptoms over 18 months and follow-up electrodiagnosis was essentially normal (one muscle in 1 subject had 3/10 polyphasic motor units). CONCLUSIONS MRI changes, motor unit changes on EMG needle examination, and low paraspinal mapping scores are not uncommon in asymptomatic older adults with spinal stenosis or disk herniation and may lead to false positive tests. The stricter criterion of abnormal spontaneous activity on needle examination and paraspinal mapping scores greater than 6 offered in this paper lowers the risk of false positive EMG testing. SIGNIFICANCE EMG is less likely to be abnormal (false positive) in asymptomatic adults than MRI.

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 physician's diagnosis of clinical spinal stenosis was significantly related to the neurological findings on examination (p < 0.05) and to the spine surgeon's 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.

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.

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.

OBJECTIVE To assess the relations between clinically recognized lumbar spinal stenosis and the conclusions of masked radiologists and electrodiagnosticians. DESIGN Prospective, masked, double-controlled trial. SETTING University spine center. PARTICIPANTS One hundred fifty persons age 55 to 80 years with or without back pain and with or without magnetic resonance imaging (MRI)-demonstrated stenosis, screened for neuropathy risk, previous surgery, or cancer. INTERVENTIONS Questionnaires on pain and function; ambulation testing and physical examination; and masked electrodiagnotics and MRI. MAIN OUTCOME MEASURE Diagnostic impressions of the examining clinician, radiologist, and electrodiagnostician. RESULTS Following application of post hoc exclusion criteria and elimination of patients due to incomplete or inadequate test data, the clinical diagnosis was lumbar stenosis in 50 subjects, back pain in 44 subjects, and no pain in 32 subjects. Radiologic and clinical impression had no relation (P =.80 vs asymptomatic, P =.99 vs back pain controls). Electrodiagnostic impression trended to relate to clinical impression (P =.14 vs asymptomatic, P =.09 vs back pain). Retrospective application of age-related electrodiagnostic norms for paraspinal electromyographic and limb motor unit changes, established in this study, reclassified 13 of the 17 asymptomatic persons whom the electrodiagnostician thought had stenosis. The clinical impression did correspond to history and physical examination findings typically associated with spinal stenosis and to the independent impression of a neurosurgeon who examined MRI and clinical, but not to the electrodiagnostic data. CONCLUSIONS The impression obtained from an MRI scan does not determine whether lumbar stenosis is a cause of pain. Electrodiagnostic consultation may be useful, especially if age-related norms obtained in this study are applied.