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 1$^{st}$ postoperative week (p < 0.001) and remained 37% lower in the 2$^{nd}$ (p < 0.001) and 23% lower in the 4$^{th}$ 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

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

Postoperative Complication Burden, Revision Risk, and Health Care Use in Obese Patients Undergoing Primary Adult Thoracolumbar Deformity Surgery

Study Design: This is a retrospective cohort study using a nationally representative administrative database. Objective: To identify the impact of obesity on postoperative outcomes in patients undergoing thoracolumbar adult spinal deformity (ASD) surgery. Background: The obesity rate in the United States remains staggering, with approximately one-third of all Americans being overweight or obese. However, the impact of elevated body mass index on spine surgery outcomes remains unclear. Methods: We queried the MarketScan database to identify patients who were diagnosed with a spinal deformity and underwent ASD surgery from 2007 to 2016. Patients were then stratified by whether or not they were diagnosed as obese at index surgical admission. Propensity score matching (PSM) was then utilized to mitigate intergroup differences between obese and nonobese patients. Patients <18 years and those with any prior history of trauma or tumor were excluded from this study. Baseline demographics and comorbidities, postoperative complication rates, and short- and long-term reoperation rates were determined. Results: A total of 7423 patients met the inclusion criteria of this study, of whom 597 (8.0%) were obese. Initially, patients with obesity had a higher 90-day postoperative complication rate than nonobese patients (46.1% vs 40.8%, P < .05); however, this difference did not remain after PSM. Revision surgery rates after 2 years were similar across the 2 groups following primary surgery (obese, 21.4%, vs nonobese, 22.0%; P = .7588). Health care use occurred at a higher rate among obese patients through 2 years of long-term follow-up (obese, $152 930, vs nonobese,$140 550; P < .05). Conclusion: Patients diagnosed with obesity who underwent ASD surgery did not demonstrate increased rates of complications, reoperations, or readmissions. However, overall health care use through 2 years of follow-up after index surgery was higher in the obesity cohort

Objective measures of functional impairment for degenerative diseases of the lumbar spine: a systematic review of the literature

BACKGROUND CONTEXT: The accurate determination of a patient's functional status is necessary for therapeutic decision-making and to critically appraise treatment efficacy. Current subjective patient-reported outcome measure (PROM)-based assessments have limitations and can be complimented by objective measures of function. PURPOSE: To systematically review the literature and provide an overview on the available objective measures of function for patients with degenerative diseases of the lumbar spine. STUDY DESIGN/SETTING: Systematic review of the literature. METHODS: The PRISMA guidelines were followed. Two reviewers independently searched the PubMed, Web of Science, EMBASE and SCOPUS databases for permutations of the words "objective", "assessment", "function", "lumbar" and "spine", including articles on human subjects with degenerative diseases of the lumbar spine that reported on objective measures of function, published until September 2018. No funding was received. The authors report no conflicts of interest. RESULTS: Of 2389 identified articles, 82 were included in the final analysis. There was a significant increase of 0.12 per year in the number of publications dealing with objective measures of function since 1989 (95% CI 0.08-0.16, p<0.001). Some publications studied multiple diagnoses and objective measures. The US was the leading nation in terms of scientific output for objective outcome measures (n=21; 25.6%), followed by Switzerland (n=17; 20.7%), Canada, Germany and the United Kingdom (each n=6; 7.3%). Our search revealed 21 different types of objective measures, predominantly applied to patients with lumbar spinal stenosis (n=67 publications; 81.7%), chronic/unspecific low back pain (n=28; 34.2%) and lumbar disc herniation (n=22; 26.8%). The Timed-Up-and-Go (TUG) test was the most frequently applied measure (n=26 publications; 31.7%; cumulative number of reported subjects: 5181), followed by the Motorized Treadmill Test (MTT; n=25 publications; 30.5%, 1499 subjects) and with each n=9 publications (11.0%) the Five-Repetition Sit-To-Stand test (5R-STS; 955 subjects), as well as accelerometry analyses (336 subjects). The reliability and validity of many of the less-applied objective measures was uncertain. There was profound heterogeneity in their application and interpretation of results. Risk of bias was not assessed. CONCLUSIONS: Clinical studies on patients with lumbar degenerative diseases increasingly employ objective measures of function, which offer high potential for improving the quality of outcome measurement in patient-care and research. This review provides an overview on available options. Our findings call for an agreement and standardization in terms of test selection, conduction and analysis to facilitate comparison of results across cohorts

Digital transformation in spine research and outcome assessment

Letter to the Editor Digital transformation in spine research and outcome assessmen

A Comparative Analysis of Patients Undergoing Fusion for Adult Cervical Deformity by Approach Type

Study Design: Retrospective cohort study. Objective: To provide insight into postoperative complications, short-term quality outcomes, and costs of the surgical approaches of adult cervical deformity (ACD). Methods: A national database was queried from 2007 to 2016 to identify patients who underwent cervical fusion for ACD. Patients were stratified by approach type—anterior, posterior, or circumferential. Patients undergoing anterior and posterior approach surgeries were additionally compared using propensity score matching. Results: A total of 6575 patients underwent multilevel cervical fusion for ACD correction. Circumferential fusion had the highest postoperative complication rate (46.9% vs posterior: 36.7% vs anterior: 18.5%, P < .0001). Anterior fusion patients more commonly required reoperation compared with posterior fusion patients (P < .0001), and 90-day readmission rate was highest for patients undergoing circumferential fusion (P < .0001). After propensity score matching, the complication rate remained higher in the posterior, as compared to the anterior fusion group (P < .0001). Readmission rate also remained higher in the posterior fusion group; however, anterior fusion patients were more likely to require reoperation. At index hospitalization, posterior fusion led to 1.5× higher costs, and total payments at 90 days were 1.6× higher than their anterior fusion counterparts. Conclusion: Patients who undergo posterior fusion for ACD have higher complication rates, readmission rates, and higher cost burden than patients who undergo anterior fusion; however, posterior correction of ACD is associated with a lower rate of reoperation

Timing of Adjuvant Radiation Therapy and Risk of Wound-Related Complications Among Patients With Spinal Metastatic Disease

Study Design: This was an epidemiological study using national administrative data from the MarketScan database. Objective: To investigate the impact of early versus delayed adjuvant radiotherapy (RT) on wound healing following surgical resection for spinal metastatic disease. Methods: We queried the MarketScan database (2007-2016), identifying patients with a diagnosis of spinal metastasis who also underwent RT within 8 weeks of surgery. Patients were categorized into “Early RT” if they received RT within 4 weeks of surgery and as “Late RT” if they received RT between 4 and 8 weeks after surgery. Descriptive statistics and hypothesis testing were used to compare baseline characteristics and wound complication outcomes. Results: A total of 540 patients met the inclusion criteria: 307 (56.9%) received RT within 4 weeks (Early RT) and 233 (43.1%) received RT within 4 to 8 weeks (Late RT) of surgery. Mean days to RT for the Early RT cohort was 18.5 (SD, 6.9) and 39.7 (SD, 7.6) for the Late RT cohort. In a 90-day surveillance period, n = 9 (2.9%) of Early RT and n = 8 (3.4%) of Late RT patients developed wound complications (P = .574). Conclusions: When comparing patients who received RT early versus delayed following surgery, there were no significant differences in the rates of wound complications. Further prospective studies should aim to identify optimal patient criteria for early postoperative RT for spinal metastases

Association between Physician Industry Payments and Cost of Anterior Cervical Discectomy and Fusion in Medicare Beneficiaries

BACKGROUND Neurosurgical spine specialists receive considerable amounts of industry support which may impact the cost of care. The aim of this study was to evaluate the association between industry payments received by spine surgeons and the total hospital and operating room (OR) costs of an anterior cervical discectomy and fusion (ACDF) procedure among Medicare beneficiaries. METHODS All ACDF cases were identified among the Medicare Carrier Files, from January 1, 2013, to December 31, 2014, and matched to the Medicare Inpatient Baseline File. The total hospital and OR charges were obtained for these cases. Charges were converted to cost using year-specific cost-to-charge ratios. Surgeons were identified among Open Payments database, which is used to quantify industry support. Analyses was performed to examine the association between industry payments received and ACDF costs. RESULTS Matching resulting in the inclusion of 2,209 ACDF claims from 2013-2014. In 2013 and 2014, the mean total cost for an ACDF was $21,798 and$21,008, respectively; mean OR cost was $5,878 and$6,064, respectively. Mann-Whitney U test demonstrated no significant differences in the mean total or OR cost for an ACDF based on quartile of general industry payment received (p=0.21 and p=0.54), and linear regression found no association between industry general payments, research support, or investments on the total hospital cost (p=0.41, p=0.13, and p=0.25), or OR cost for an ACDF (p=0.35, p=0.24, and p=0.40). CONCLUSIONS This study suggests that spine surgeons performing ACDF surgeries may receive industry support without impacting the cost of care