Standardizing Continuous Physical Activity Monitoring in Patients with Cervical Spondylosis.

STUDY DESIGN/SETTING: Prospective cohort study. OBJECTIVE: To use a commercial wearable device to measure real-life, continuous physical activity in patients with CS and to establish age- and sex-adjusted standardized scores. SUMMARY OF BACKGROUND DATA: Patients with cervical spondylosis (CS) often present with pain or neurologic deficits that results in functional limitations and inactivity. However, little is known regarding the influence of CS on patient's real-life physical activity. METHODS: This study included 100 English-speaking adult patients with cervical degenerative diseases undergoing elective spine surgery at Stanford University who owned iPhones. Patients undergoing surgery for spine infections, trauma, or tumors, or with lumbar degenerative disease were excluded. Activity two weeks before surgery was expressed as raw daily step counts. Standardized z-scores were calculated based on age- and sex-specific values of a control population. Responses to patient-reported outcome measures (PROMs) surveys assessed convergent validity. Functional impairment was categorized based on predetermined z-score cut-off values. RESULTS: 30 CS with mean(±SD) age of 56.0(±13.4) years wore an Apple Watch for ≥8 hours/day in 87.1% of the days. Mean watch wear time was 15.7(±4.2) hours/day, and mean daily step count was 6,400(±3,792). There was no significant difference in activity between 13 patients (43%) with myelopathy and 17 (57%) without myelopathy. Test-Retest reliability between wearable step count measurements was excellent (ICC ß=0.95). Physical activity showed a moderate positive correlation with SF36-PCS, EQ5D VAS, and PROMIS-PF. Activity performance was classified into categories of "no impairment" (step count=9,640(±2,412)), "mild impairment" (6,054(±816)), "moderate impairment" (3,481(±752)), and "severe impairment" (1,619(±240)). CONCLUSION: CS patients' physical activity is significantly lower than the general population, or the frequently stated goals of 7,000-10,000 steps/day. Standardized, continuous wearable physical activity monitoring in CS is a reliable, valid, and normalized outcome tool that may help characterize functional impairment before and after spinal interventions.

Standardizing Physical Activity Monitoring in Patients With Degenerative Lumbar Disorders.

BACKGROUND AND OBJECTIVES: Degenerative thoracolumbar disorders (DTDs) typically cause pain and functional impairment. However, little is known regarding the DTD impact on patient's real-life physical activity. The objective of this study is to validate a wearable measure of physical activity monitoring in patients with DTD and to create gender- and sex-specific performance thresholds that are standardized to the mean of a control population. METHODS: A commercially available smartwatch (Apple Watch) was used to monitor preoperative physical activity in patients undergoing surgery for DTD. Mean preoperative physical activity 2 weeks before the scheduled surgery was expressed as raw step count. Standardized z-scores were referenced to age- and sex-specific values of a control population from a large public database. Step counts were assessed for convergent validity with established patient-reported outcome measures, and impairment in activity was stratified into performance groups based on z-score cutoff values. RESULTS: Sixty-five patients (62% female) with a mean (±SD) age of 63.8 (±12.8) years had a mean preoperative daily step count of 5556 (±3978). Physical activity showed significant correlation with patient-reported outcome measures, including Oswestry disability index (r = -0.26, 95% CI: -0.47-0.01), 36-Item Short Form Survey Physical Component Summary score (r = 0.30, 95% CI: 0.06-0.51), and Patient-Reported Outcomes Measurement Information System Physical Function (r = 0.49, 95% CI: 0.27-0.65). "No," "Mild," "moderate," and "severe impairment" in activity performance were defined as corresponding z-scores of >0, 0 to -0.99, -1 to -1.99, and ≤-2, accounting for 22%, 34%, 40%, and 5% of the study population. Each one-step category increase in activity impairment resulted in increased subjective disability as measured by the Oswestry Disability Index, 36-Item Short Form Survey Physical Component Summary, and Patient-Reported Outcomes Measurement Information System Physical Function (all P -values <.05). CONCLUSION: We establish the first wearable objective measure of real-life physical activity for patients with DTD, with the first age- and sex-adjusted standard scores to enable clinicians and researchers to set treatment goals and directly compare activity levels between individual patients with DTD and normal controls.

Consensus on a standardised treatment pathway algorithm for lumbar spinal stenosis: an international Delphi study.

BACKGROUND: Lumbar spinal stenosis (LSS) is a common degenerative spinal condition in older adults associated with disability, diminished quality of life, and substantial healthcare costs. Individual symptoms and needs vary. With sparse and sometimes inconsistent evidence to guide clinical decision-making, variable clinical care may lead to unsatisfactory patient outcomes and inefficient use of healthcare resources. METHODS: A three-phase modified Delphi study comprising four consensus rounds was conducted on behalf of the International Taskforce for the Diagnosis and Management of LSS to develop a treatment algorithm based on multi-professional international expert consensus. Participants with expertise in the assessment and management of people with LSS were invited using an international distribution process used for two previous Delphi studies led by the Taskforce. Separate treatment pathways for patients with different symptom types and severity were developed and incorporated into a proposed treatment algorithm through consensus rounds 1 to 3. Agreement with the proposed algorithm was evaluated in the final consensus round. RESULTS: The final algorithm combines stratified and stepped approaches. When indicated, immediate investigation and surgery is advocated. Otherwise, a stepped approach is suggested when self-directed care is unsatisfactory. This starts with tailored rehabilitation, then more complex multidisciplinary care, investigations and surgery options if needed. Treatment options in each step depend on clinical phenotype and symptom severity. Treatment response guides pathway entrance and exit points. Of 397 study participants, 86% rated their agreement ≥ 4 for the proposed algorithm on a 0-6 scale, of which 22% completely agreed. Only 7% disagreed. Over 70% of participants felt that the algorithm would be useful for clinicians in public healthcare (both primary care and specialist settings) and in private healthcare settings, and that a simplified version would help patients in shared decision-making. CONCLUSIONS: International and multi-professional agreement was achieved for a proposed LSS treatment algorithm developed through expert consensus. The algorithm advocates different pathway options depending on clinical indications. It is not intended as a treatment protocol and will require evaluation against current care for clinical and cost-effectiveness. It may, however, serve as a clinical guide until evidence is sufficient to inform a fully stratified care model.

Variability among methods and timing of pain assessment tools for tracking improvement of lumbar stenosis patients after surgery.

BACKGROUND CONTEXT: Many different pain and functional outcomes are used to determine progress after surgical intervention for lumbar spinal stenosis (LSS); it is unknown how these different outcomes correlate, or whether timing of pain measurement is important. PURPOSE: The goal was to determine whether method and timing of pain measurement is important in the context of LSS surgical outcomes. STUDY DESIGN/SETTING: Cohort study. PATIENT SAMPLE: LSS patients (N=21). OUTCOME MEASURES: Self-report measures. METHODS: Each patient completed the 36-item Short Form, Oswestry Disability Index, and Swiss Spinal Stenosis Questionnaire 1 week presurgery and 6 months postsurgery. Objective function was measured using the Self-Paced Walking Test (SPWT). Low back and leg pain were assessed by visual analogue scale both immediately before the SPWT (prewalking pain) and at the symptom-limited endpoint (provoked pain). Pain was also assessed before and after surgery using the pain subscales of 36-item Short Form pain, Oswestry Disability Index, and Swiss Spinal Stenosis Questionnaire. RESULTS: Patients averaged 65.3 years of age with 15 being female. After surgery, all outcome measures improved significantly. Postwalking pain (provoked pain) demonstrating a strong relationship with objectively measured function (SPWT). Pain (visual analogue scale prewalk and postwalk) showed little correlation with reported changes in disability, general health or physical function. CONCLUSIONS: Our results suggest that for patients with LSS, the context of the pain measurement matters, and it is important to measure pain after walking (provoked pain). Results also suggest that when examining the relationship between pain and function, objective measures of function are preferable (eg, a walking test). Finally, given the lack of association between measures of pain, it is important to understand that each pain measure is addressing a different pain construct. Therefore, when conducting outcomes studies, it is imperative to compare the exact same pain measures across time points.

Objective activity tracking in spine surgery: a prospective feasibility study with a low-cost consumer grade wearable accelerometer.

Patient-reported outcome measures (PROMs) are commonly used to estimate disability of patients with spinal degenerative disease. Emerging technological advances present an opportunity to provide objective measurements of activity. In a prospective, observational study we utilized a low-cost consumer grade wearable accelerometer (LCA) to determine patient activity (steps per day) preoperatively (baseline) and up to one year (Y1) after cervical and lumbar spine surgery. We studied 30 patients (46.7% male; mean age 57 years; 70% Caucasian) with a baseline activity level of 5624 steps per day. The activity level decreased by 71% in the 1st postoperative week (p < 0.001) and remained 37% lower in the 2nd (p < 0.001) and 23% lower in the 4th week (p = 0.015). At no time point until Y1 did patients increase their activity level, compared to baseline. Activity was greater in patients with cervical, as compared to patients with lumbar spine disease. Age, sex, ethnic group, anesthesia risk score and fusion were variables associated with activity. There was no correlation between activity and PROMs, but a strong correlation with depression. Determining activity using LCAs provides real-time and longitudinal information about patient mobility and return of function. Recovery took place over the first eight postoperative weeks, with subtle improvement afterwards.

Digital biomarkers of spine and musculoskeletal disease from accelerometers: Defining phenotypes of free-living physical activity in knee osteoarthritis and lumbar spinal stenosis.

BACKGROUND CONTEXT: Lumbar spinal stenosis (LSS) and knee osteoarthritis (OA) are 2 of the leading causes of disability worldwide. In order to provide disease-specific prescriptions for physical activity, there is a clear need to better understand physical activity in daily life (performance) in these populations. PURPOSE: To discover performance phenotypes for LSS and OA by applying novel analytical methods to accelerometry data. Specific objectives include the following: (1) to identify characteristic features (phenotypes) of free-living physical activity unique to individuals with LSS and OA, and (2) to determine which features can best differentiate between these conditions. STUDY DESIGN AND SETTING: Leveraging data from 3 existing cross-sectional cohorts, accelerometry signal feature characterization and selection were performed in a computational laboratory. PATIENT SAMPLE: Data from a total of 4,028 individuals were analyzed from the following 3 datasets: LSS Accelerometry Database (n=75); OA Initiative (n=1950); and the 2003 to 2004 National Health and Nutrition Examination Survey (pain-free controls, n=2003). METHODS: In order to characterize the accelerometry signals, data were examined using (1) standard intervals for counts/minute from Freedson et al. and (2) the physical performance intervals for mobility-limited pain populations. From this, 42 novel accelerometry features were defined and evaluated for significance in discriminating between the groups (LSS, OA, and controls) in order to then determine which sparse set of features best differentiates between the groups. These sparse sets of features defined the performance phenotypes. OUTCOME MEASURES: Accelerometry features and their ability to differentiate between individuals with LSS, OA, and controls. RESULTS: Given age and gender, classification rates were at least 80% accurate (pairwise) between diseased and pain-free populations (LSS vs. controls and OA vs. controls). The most important features to distinguish between disease groups corresponded to measures in the light and sedentary activity intervals. The more subtle classification between diseased populations (LSS vs. OA) was 72% accurate, with light and moderate activity providing the prominent distinguishing features. CONCLUSIONS: We describe the discovery of performance phenotypes of LSS and OA from accelerometry data, revealed through a novel set of features that characterize daily patterns of movement in people with LSS and OA. These performance phenotypes provide a new method for analyzing free-living physical activity (performance) in LSS and OA, and provide the groundwork for more personalized approaches to measuring and improving function.

Objective measurement of function following lumbar spinal stenosis decompression reveals improved functional capacity with stagnant real-life physical activity.

BACKGROUND CONTEXT: Lumbar spinal stenosis (LSS) is a prevalent and costly condition associated with significant dysfunction. Alleviation of pain and improvement of function are the primary goals of surgical intervention. Although prior studies have measured subjective improvements in function after surgery, few have examined objective markers of functional improvement. PURPOSE: We aimed to objectively measure and quantify changes in physical capacity and physical performance following surgical decompression of LSS. STUDY DESIGN/SETTING: Prospective cohort study. PATIENT SAMPLE: Thirty-eight patients with LSS determined by the treating surgeon's clinical and imaging evaluation, and who were scheduled for surgical treatment, were consecutively recruited at two academic medical facilities, with 28 providing valid data for analysis at baseline and 6 months after surgery. OUTCOME MEASURES: Before surgery and at 6 months after surgery, participants provided 7 days of real-life physical activity (performance) using ActiGraph accelerometers; completed two objective functional capacity measures, the Short Physical Performance Battery and Self-Paced Walking Test; and completed three subjective functional outcome questionnaires, Oswestry Disability Index, Spinal Stenosis Symptom Questionnaire, and Short-Form 36. METHODS: Physical activity, as measured by continuous activity monitoring, was analyzed as previously described according to the 2008 American Physical Activity Guidelines. Paired t tests were performed to assess for postsurgical changes in all questionnaire outcomes and all objective functional capacity measures. Chi-square analysis was used to categorically assess whether patients were more likely to meet these physical activity recommendations after surgery. RESULTS: Participants were 70.1 years old (±8.9) with 17 females (60.7%) and an average body mass index of 28.4 (±6.2). All subjective measures (Oswestry Disability Index, Spinal Stenosis Symptom Questionnaire, and Short-Form 36) improved significantly at 6 months after surgery, as did objective functional measures of capacity including balance, gait speed, and ambulation distance (Short Physical Performance Battery, Self-Paced Walking Test). However, objectively measured performance (real-life physical activity) did not change following surgery. Although fewer participants qualified as inactive (54% vs. 71%), and more (11% vs. 4%) met the physical activity guideline recommendations at the 6-month follow-up, these differences were not statistically significant (p=.22) CONCLUSIONS: This is the first study, of which we are aware, to objectively evaluate changes in postsurgical performance (real-life physical activity) in people with LSS. We found that at 6 months after surgery for LSS, participants demonstrated significant improvements in self-reported function and objectively measured physical capacity, but not physical performance as measured by continuous activity monitoring. This lack of improvement in performance, despite improvements in self-reported function and objective capacity, suggests a role for postoperative rehabilitation focused specifically on increasing performance after surgery in the LSS population.

Physical performance analysis: A new approach to assessing free-living physical activity in musculoskeletal pain and mobility-limited populations.

BACKGROUND: Accurate measurement of physical performance in individuals with musculoskeletal pain is essential. Accelerometry is a powerful tool for this purpose, yet the current methods designed to evaluate energy expenditure are not optimized for this population. The goal of this study is to empirically derive a method of accelerometry analysis specifically for musculoskeletal pain populations. METHODS: We extracted data from 6,796 participants in the 2003-4 National Health and Nutrition Examination Survey (NHANES) including: 7-day accelerometry, health and pain questionnaires, and anthropomorphics. Custom macros were used for data processing, complex survey regression analyses, model selection, and statistical adjustment. After controlling for a multitude of variables that influence physical activity, we investigated whether distinct accelerometry profiles accompany pain in different locations of the body; and we identified the intensity intervals that best characterized these profiles. RESULTS: Unique accelerometry profiles were observed for pain in different body regions, logically clustering together based on proximity. Based on this, the following novel intervals (counts/minute) were identified and defined: Performance Sedentary (PSE) = 1-100, Performance Light 1 (PL1) = 101-350, Performance Light 2 (PL2) = 351-800, Performance Light 3 (PL3) = 801-2500, and Performance Moderate/Vigorous (PMV) = 2501-30000. The refinement of accelerometry signals into these new intervals, including 3 distinct ranges that fit inside the established light activity range, best captures alterations in real-life physical performance as a result of regional pain. DISCUSSION AND CONCLUSIONS: These new accelerometry intervals provide a model for objective measurement of real-life physical performance in people with pain and musculoskeletal disorders, with many potential uses. They may be used to better evaluate the relationship between pain and daily physical function, monitor musculoskeletal disease progression, gauge disease severity, inform exercise prescription, and quantify the functional impact of treatments. Based on these findings, we recommend that future studies of pain and musculoskeletal disorders analyze accelerometry output based on these new "physical performance" intervals.

Surgical Versus Nonsurgical Treatment for Lumbar Spinal Stenosis.

STUDY DESIGN: A systematic review. OBJECTIVES: The aim of this study is to evaluate the effectiveness of different types of surgery compared with different types of nonsurgical interventions in adults with symptomatic lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA: LSS is a debilitating condition associated with degeneration of the spine with aging. People with LSS experience a range of symptoms, including back pain, leg pain, numbness and tingling in the legs, and reduced physical function. Main treatment options are surgery, physical therapy, exercise, braces, and injections into the spine. METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, five other databases, and two trials registries up to February 2015, reference lists, and conference proceedings related to treatment of the spine. Randomized controlled trials (RCTs) compared surgical versus nonoperative treatments in participants with LSS.Outcomes included quality of life, disability, function, pain, complication rates, and side effects. RESULTS: From the 12,966 citations screened, we included five RCTs (643 participants).Three studies compared spine surgery versus various types of nonsurgical treatment. It is difficult to draw conclusions from these studies because nonsurgical treatments were inadequately described. One study that compared surgery versus bracing and exercise found no differences in pain. Another study compared surgery versus spinal injections and found better physical function with injections, and better pain relief with surgery at six weeks. Still another trial compared surgery with an implanted device versus nonsurgical care. This study reported favorable outcomes of surgery for symptoms and physical function. CONCLUSION: We cannot conclude on the basis of this review whether surgical or nonsurgical treatment is better for individuals with LSS. Nevertheless, we can report on the high rate of effects reported in three of five surgical groups, ranging from 10% to 24%. No side effects were reported for any of the conservative treatment options. LEVEL OF EVIDENCE: 1.

Surgical versus non-surgical treatment for lumbar spinal stenosis.

BACKGROUND: Lumbar spinal stenosis (LSS) is a debilitating condition associated with degeneration of the spine with aging. OBJECTIVES: To evaluate the effectiveness of different types of surgery compared with different types of non-surgical interventions in adults with symptomatic LSS. Primary outcomes included quality of life, disability, function and pain. Also, to consider complication rates and side effects, and to evaluate short-, intermediate- and long-term outcomes (six months, six months to two years, five years or longer). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, five other databases and two trials registries up to February 2015. We also screened reference lists and conference proceedings related to treatment of the spine. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing surgical versus non-operative treatments in participants with lumbar spinal stenosis confirmed by clinical and imaging findings. DATA COLLECTION AND ANALYSIS: For data collection and analysis, we followed methods guidelines of the Cochrane Back and Neck Review Group (Furlan 2009) and those provided in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). MAIN RESULTS: From the 12,966 citations screened, we assessed 26 full-text articles and included five RCTs (643 participants).Low-quality evidence from the meta-analysis performed on two trials using the Oswestry Disability Index (pain-related disability) to compare direct decompression with or without fusion versus multi-modal non-operative care showed no significant differences at six months (mean difference (MD) -3.66, 95% confidence interval (CI) -10.12 to 2.80) and at one year (MD -6.18, 95% CI -15.03 to 2.66). At 24 months, significant differences favoured decompression (MD -4.43, 95% CI -7.91 to -0.96). Low-quality evidence from one small study revealed no difference in pain outcomes between decompression and usual conservative care (bracing and exercise) at three months (risk ratio (RR) 1.38, 95% CI 0.22 to 8.59), four years (RR 7.50, 95% CI 1.00 to 56.48) and 10 years (RR 4.09, 95% CI 0.95 to 17.58).Low-quality evidence from one small study suggested no differences at six weeks in the Oswestry Disability Index for patients treated with minimally invasive mild decompression versus those treated with epidural steroid injections (MD 5.70, 95% CI 0.57 to 10.83; 38 participants). Zurich Claudication Questionnaire (ZCQ) results were better for epidural injection at six weeks (MD -0.60, 95% CI -0.92 to -0.28), and visual analogue scale (VAS) improvements were better in the mild decompression group (MD 2.40, 95% CI 1.92 to 2.88). At 12 weeks, many cross-overs prevented further analysis.Low-quality evidence from a single study including 191 participants favoured the interspinous spacer versus usual conservative treatment at six weeks, six months and one year for symptom severity and physical function.All remaining studies reported complications associated with surgery and conservative side effects of treatment: Two studies reported no major complications in the surgical group, and the other study reported complications in 10% and 24% of participants, including spinous process fracture, coronary ischaemia, respiratory distress, haematoma, stroke, risk of reoperation and death due to pulmonary oedema. AUTHORS' CONCLUSIONS: We have very little confidence to conclude whether surgical treatment or a conservative approach is better for lumbar spinal stenosis, and we can provide no new recommendations to guide clinical practice. However, it should be noted that the rate of side effects ranged from 10% to 24% in surgical cases, and no side effects were reported for any conservative treatment. No clear benefits were observed with surgery versus non-surgical treatment. These findings suggest that clinicians should be very careful in informing patients about possible treatment options, especially given that conservative treatment options have resulted in no reported side effects. High-quality research is needed to compare surgical versus conservative care for individuals with lumbar spinal stenosis.

Management of lumbar spinal stenosis.

Lumbar spinal stenosis (LSS) affects more than 200,000 adults in the United States, resulting in substantial pain and disability. It is the most common reason for spinal surgery in patients over 65 years. Lumbar spinal stenosis is a clinical syndrome of pain in the buttocks or lower extremities, with or without back pain. It is associated with reduced space available for the neural and vascular elements of the lumbar spine. The condition is often exacerbated by standing, walking, or lumbar extension and relieved by forward flexion, sitting, or recumbency. Clinical care and research into lumbar spinal stenosis is complicated by the heterogeneity of the condition, the lack of standard criteria for diagnosis and inclusion in studies, and high rates of anatomic stenosis on imaging studies in older people who are completely asymptomatic. The options for non-surgical management include drugs, physiotherapy, spinal injections, lifestyle modification, and multidisciplinary rehabilitation. However, few high quality randomized trials have looked at conservative management. A systematic review concluded that there is insufficient evidence to recommend any specific type of non-surgical treatment. Several different surgical procedures are used to treat patients who do not improve with non-operative therapies. Given that rapid deterioration is rare and that symptoms often wax and wane or gradually improve, surgery is almost always elective and considered only if sufficiently bothersome symptoms persist despite trials of less invasive interventions. Outcomes (leg pain and disability) seem to be better for surgery than for non-operative treatment, but the evidence is heterogeneous and often of limited quality.

Does physical activity influence the relationship between low back pain and obesity?

BACKGROUND CONTEXT: Evidence supporting an association between obesity and low back pain (LBP) continues to grow; yet little is known about the cause and effect of this relationship. Even less is known about the mechanisms linking the two. Physical activity is a logical suspect, but no study has demonstrated its role. PURPOSE: This study was designed to examine the interrelationship between physical activity, obesity, and LBP. The specific aims were to determine if obesity is a risk factor for LBP in the U.S. population, measure the strength of any observed association, and evaluate the role of physical activity in modulating this association. STUDY DESIGN/SETTING: A cross-sectional U.S. population-based study. PATIENT SAMPLE: A cohort of 6,796 adults from the 2003-2004 National Health and Nutrition Examination Survey. OUTCOME MEASURES: Demographic information, an in-depth health questionnaire, physical examination details, and 7-day free-living physical activity monitoring using accelerometry (ActiGraph AM-7164; ActiGraph, Pensacola, FL, USA). METHODS: LBP status was determined by questionnaire response. Body mass index (BMI) was calculated during physical examination and divided here into four groups (normal weight <25, overweight 25-30, obese 31-35, and ultraobese 36+). Summary measures of physical activity were computed based on intensity cutoffs, percentile intensities, and bout. Demographics, social history, and comorbid health conditions were used to build adjusted weighted logistic regression models constructed using Akaike Information Criterion. All displayed estimates are significant at level <.05. No external funding was received to support this study. None of the authors report conflicts of interest directly related to the specific subject matter of this manuscript. RESULTS: In the U.S. population, the risk of low LBP increases in step with BMI from 2.9% for normal BMI (20-25) to 5.2% for overweight (26-30), 7.7% for obese (31-35), and 11.6% for ultraobese (36+). Smoking is consistently the strongest predictor of LBP across the BMI spectrum (odds ratio 1.6-2.9). Physical activity also modulates these risks. In the overall model, the best physical activity predictors of LBP are in the moderate and high intensity ranges with small effects (odds ratio 0.98 and 0.996 per standard deviation increase, respectively). When broken down by BMI, time spent in sedentary and moderate activity ranges demonstrate more robust influences on LBP status in the overweight, obese, and ultraobese groups. CONCLUSIONS: Increased BMI is a risk factor for back pain in Americans. More important, the role of physical activity in mitigating back pain risk is shown to be of greater consequence in the overweight and obese populations.

Reliability of the clinical examination in the diagnosis of neurogenic versus vascular claudication.

BACKGROUND CONTEXT: As research increasingly challenges the diagnostic accuracy of advanced imaging for lumbar spinal stenosis, the impression gleaned from the office evaluation becomes more important. Neurogenic claudication is a hallmark of lumbar spinal stenosis, but the reliability of clinical impression of claudication has not been studied. PURPOSE: To determine the reliability of the clinical examination for neurogenic claudication in an idealized setting. STUDY DESIGN: Prospective masked controlled trial. PATIENT SAMPLE: Persons aged 55 to 90 years were recruited to form three groups: those offered surgery for spinal stenosis by academic spine surgeons, those who had peripheral vascular symptoms and positive ankle-brachial index (ABI), and those who were asymptomatic. All were extensively screened against confounding diseases. Forty-three neurogenic, 12 vascular, and 35 asymptomatic recruits were tested. OUTCOME MEASURES: Clinical impression of neurogenic claudication. METHODS: A neurosurgeon and a vascular surgeon, masked to each other's findings, imaging, and recruitment status, performed a codified but unconstrained comprehensive spine and vascular history and physical examination for each subject. The surgeon's impression was recorded. RESULTS: Masked surgeons strongly agreed with the recruitment diagnosis (neurosurgeon kappa 0.761, vascular surgeon kappa 0.803, both p<.001) and with each other (kappa 0.717, p<.001). However, disagreements did occur between examiners and recruitment diagnosis (neurosurgeon n=13 cases, vascular surgeon n=10) and between examiners (n=14 cases). Pain level and marginally some measures of disability related to the agreement, but specific aspects of the physical examination, showed poor interrater reliability and did not contribute to the agreement. CONCLUSIONS: The clinical impression of neurogenic claudication is a reliable construct. The history, but not the poorly reproduced physical examination, contributes to reliability. The level of disagreement between experts in this simplified, yet severely involved, population raises concern about the risk of misdiagnosis in individual cases. Thus, surgical and other consequential decisions about diagnosis may require ancillary tests such as electromyography or ABI.