Aman Sinha

Objective Measurement of Free-Living Physical Activity (Performance) in Lumbar Spinal Stenosis: Are Physical Activity Guidelines Being Met?

BACKGROUND Research suggests that people with lumbar spinal stenosis (LSS) would benefit from increased physical activity. Yet, to date, we do not have disease-specific activity guidelines for LSS, and the nature of free-living physical activity (performance) in LSS remains unknown. LSS care providers could endorse the 2008 United States Physical Activity Guidelines; however, we do not know if this is realistic. The goal of the present study was to determine the proportion of individuals with LSS meeting the 2008 Guidelines. A secondary goal was to better understand the nature of physical performance in this population. STUDY DESIGN Retrospective study. PATIENT SAMPLE People from the Lumbar Spinal Stenosis Accelerometry Database, all of whom have both radiographic and clinical LSS and are seeking various treatments for their symptoms. OUTCOME MEASURES Seven-day accelerometry (functional outcome) and demographics (self-reported). METHODS For the present study, we analyzed only baseline data that were obtained before any new treatments. Patients with at least 4 valid days of baseline accelerometry data were included. We determined the proportion of individuals with LSS meeting the 2008 US Physical Activity Guidelines of at least 150 minutes of moderate-vigorous (MV) physical activity per week in bouts of 10 minutes or more. We also used the novel Physical Performance analysis designed by our group to determine time spent in varying intensities of activity. There are no conflicts of interest to disclose. RESULTS We analyzed data from 75 individuals with a mean age of 68 (SD 9), 37% of whom were male. Three people (4%) were considered Meeting Guidelines (at least 150 MV minutes/week), and 56 (75%) were considered Inactive with not even 1 MV minute/week. With the 10-minute bout requirement removed, 10 of 75 (13%) achieved the 150-minute threshold. The average time spent in sedentary activity was 82%, and of time spent in nonsedentary activity, 99.6% was in the light activity range. CONCLUSIONS In conclusion, the present study confirms that people with symptomatic LSS, neurogenic claudication, walking limitations, and LSS-related disability are extremely sedentary and are not meeting guidelines for physical activity. There is an urgent need for interventions aimed at reducing sedentary behavior and increasing the overall level of physical activity in LSS, not only to improve function but also to prevent diseases of inactivity. The present study suggests that reducing sedentary time, increasing time spent in light intensity activity, and increasing time spent in higher intensities of light activity may be appropriate as initial goals for exercise interventions in people with symptomatic LSS and neurogenic claudication, transitioning to moderate activity when appropriate. Results of the present study also demonstrate the importance of employing disease-specific measures for assessment of performance in LSS, and highlight the potential value of these methods for developing targeted and realistic goals for physical activity. Physical activity goals could be personalized using objective assessment of performance with accelerometry. The present study is one step toward a personalized medicine approach for people with LSS, focusing on increasing physical 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 surgeons 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.

Poster 109: Discriminating Physical Performance Phenotypes of Patients with Chronic Low Back Pain

Disclosures: Amitabh Goel: I Have No Relevant Financial Relationships To Disclose Objective: To determine the relationship of psychosocial factors as measured by patient beliefs and catastrophizing levels with pain and disability measures during conservative treatment in acute back pain subjects. Design: Observational Cohort Study. Setting: Outpatient Pain Management and Rehabilitation Clinic in a multispecialty clinic in a suburban US setting. Participants: 100 subjects with acute back pain, electing to participate in the study, were recruited from consecutive patient referrals. Interventions: Not applicable. Main Outcome Measures: Numeric Pain scale (NPS), Oswestry Disability Index (ODI), Pain Beliefs Questionnaire (PBQ) and the Pain Catastrophizing Scale (PCS). Results: There was a significant positive correlation between NPS and PCS (p 1⁄4 .03), and ODI and PCS (p < .001) at baseline, as well as at completion of treatment (p 1⁄4 .03). There was also a significant positive correlation between NPS and the PBQ Organic subscale (p 1⁄4 .001), and ODI and PBQ Organic subscale (p 1⁄4 .001) at the outset of treatment. However, at completion of treatment only the ODI and the PBQ Organic subscale correlation was significant (p < .001). There were no significant correlations with the PBQ Psychological subscale. Conclusions: In acute back pain there is a strong correlation between psychosocial factors as measured by the PBQ and PCS and the clinical measures of pain and disability as measured by the NPS and ODI. These correlations are present at baseline and are maintained throughout the course of treatment. Level of Evidence: Level IV

Dynamic management of network risk from epidemic phenomena

Despite the recent popularity of analyzing epidemic phenomena over networks, the budgeted control and protection of networks from viral propagations is not widely understood. In this paper, we blend methods from control theory and robust optimization to create a framework for network protection from epidemic environments using a limited control budget. As our emphasis is on the application of these methods to realistic contexts, our approach is designed to work with arbitrary networks, and it incorporates both decentralization as well as robustness to uncertainties in network topology. We illustrate tradeoffs between efficiency, robustness, and decentralization with respect to network protection, and we discuss methods that could build upon our framework to mitigate these tradeoffs.