How Many Steps Per Day During the Early Postoperative Period are Associated With Patient-Reported Outcomes of Disability, Pain, and Opioid Use After Lumbar Spine Surgery?

OBJECTIVE: To investigate whether early postoperative walking is associated with "best outcome" and no opioid use at 1 year after lumbar spine surgery and establish a threshold for steps/day to inform clinical practice. DESIGN: Secondary analysis from randomized controlled trial. SETTING: Two academic medical centers in the United States. PARTICIPANTS: We enrolled 248 participants undergoing surgery for a degenerative lumbar spine condition (N=248). A total of 212 participants (mean age, 62.8±11.4y, 53.3% female) had valid walking data at baseline. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Disability (Oswestry Disability Index), back and leg pain (Brief Pain Inventory), and opioid use (yes vs no) were assessed at baseline and 1 year after surgery. "Best outcome" was defined as Oswestry Disability Index ≤20, back pain ≤2, and leg pain ≤2. Steps/day (walking) was assessed with an accelerometer worn for at least 3 days and 10 h/d at 6 weeks after spine surgery, which was considered as study baseline. Separate multivariable logistic regression analyses were conducted to determine the association between steps/day at 6 weeks and "best outcome" and no opioid use at 1-year. Receiver operating characteristic curves identified a steps/day threshold for achieving outcomes. RESULTS: Each additional 1000 steps/d at 6 weeks after spine surgery was associated with 41% higher odds of achieving "best outcome" (95% confidence interval [CI], 1.15-1.74) and 38% higher odds of no opioid use (95% CI, 1.09-1.76) at 1 year. Walking ≥3500 steps/d was associated with 3.75 times the odds (95% CI, 1.56-9.02) of achieving "best outcome" and 2.37 times the odds (95% CI, 1.07-5.24) of not using opioids. CONCLUSIONS: Walking early after surgery may optimize patient-reported outcomes after lumbar spine surgery. A 3500 steps/d threshold may serve as an initial recommendation during early postoperative counseling.

Role of psychosocial factors on the effect of physical activity on physical function in patients after lumbar spine surgery.

BACKGROUND: The purpose of this study was to investigate the longitudinal postoperative relationship between physical activity, psychosocial factors, and physical function in patients undergoing lumbar spine surgery. METHODS: We enrolled 248 participants undergoing surgery for a degenerative lumbar spine condition. Physical activity was measured using a triaxial accelerometer (Actigraph GT3X) at 6-weeks (6wk), 6-months (6M), 12-months (12M) and 24-months (24M) following spine surgery. Physical function (computerized adaptive test domain version of Patient-Reported Outcomes Measurement Information System) and psychosocial factors (pain self-efficacy, depression and fear of movement) were assessed at preoperative visit and 6wk, 6M, 12M and 24M after surgery. Structural equation modeling (SEM) techniques were utilized to analyze data, and results are represented as standardized regression weights (SRW). Overall SRW were computed across five imputed datasets to account for missing data. The mediation effect of each psychosocial factor on the effect of physical activity on physical function were computed [(SRW for effect of activity on psychosocial factor X SRW for effect of psychosocial factor on function) ÷ SRW for effect of activity on function]. Each SEM model was tested for model fit by assessing established fit indexes. RESULTS: The overall effect of steps per day on physical function (SRW ranged from 0.08 to 0.19, p<0.05) was stronger compared to the overall effect of physical function on steps per day (SRW ranged from non-existent to 0.14, p<0.01 to 0.3). The effect of steps per day on physical function and function on steps per day remained consistent after accounting for psychosocial factors in each of the mediation models. Depression and fear of movement at 6M mediated 3.4% and 5.4% of the effect of steps per day at 6wk on physical function at 12M, respectively. Pain self-efficacy was not a statistically significant mediator. CONCLUSIONS: The findings of this study suggest that the relationship between physical activity and physical function is stronger than the relationship of function to activity. However, future research is needed to examine whether promoting physical activity during the early postoperative period may result in improvement of long-term physical function. Since depression and fear of movement had a very small mediating effect, additional work is needed to investigate other potential mediating factors such as pain catastrophizing, resilience and exercise self-efficacy.

Early postoperative physical activity and function: a descriptive case series study of 53 patients after lumbar spine surgery.

BACKGROUND: The purpose of this prospective case series study was to compare changes in early postoperative physical activity and physical function between 6 weeks and 3 and 6 months after lumbar spine surgery. METHODS: Fifty-three patients (mean [95% confidence interval; CI] age = 59.2 [56.2, 62.3] years, 64% female) who underwent spine surgery for a degenerative lumbar condition were assessed at 6 weeks and 3- and 6-months after surgery. The outcomes were objectively-measured physical activity (accelerometry) and patient-reported and objective physical function. Physical activity was assessed using mean steps/day and time spent in moderate to vigorous physical activity (MVPA) over a week. Physical function measures included Oswestry Disability Index (ODI), 12-item Short Form Health Survey (SF-12), Timed Up and Go (TUG), and 10-Meter Walk (10 MW). We compared changes over time in physical activity and function using generalized estimating equations with robust estimator and first-order autoregressive covariance structure. Proportion of patients who engaged in meaningful physical activity (e.g., walked at least 4400 and 6000 steps/day or engaged in at least 150 min/week in MVPA) and achieved clinically meaningful changes in physical function were compared at 3 and 6 months. RESULTS: After surgery, 72% of patients initiated physical therapy (mean [95%CI] sessions =8.5 [6.6, 10.4]) between 6 weeks and 3 months. Compared to 6 weeks post-surgery, no change in steps/day or time in MVPA/week was observed at 3 or 6 months. From 21 to 23% and 9 to 11% of participants walked at least 4400 and 6000 steps/day at 3 and 6 months, respectively, while none of the participants spent at least 150 min/week in MVPA at these same time points. Significant improvements were observed on ODI, SF-12, TUG and 10 MW (p <  0.05), with over 43 to 68% and 62 to 87% achieving clinically meaningful improvements on these measures at 3 and 6 months, respectively. CONCLUSION: Limited improvement was observed in objectively-measured physical activity from 6 weeks to 6 months after spine surgery, despite moderate to large function gains. Early postoperative physical therapy interventions targeting physical activity may be needed.

Prediction of Oswestry Disability Index (ODI) using PROMIS-29 in a national sample of lumbar spine surgery patients.

PURPOSE: The primary purpose was to examine the measurement properties of the PROMIS-29 to better understand its use in patients undergoing spine surgery. A secondary objective was to calculate a predictive equation between PROMIS-29 and ODI, to allow clinicians and researchers to determine a predicted ODI score based on PROMIS short form scores. METHODS: 719 patients with PROMIS v2.0 and ODI responses were queried from the quality outcomes database. Validity was assessed using coefficient omega, ceiling/floor effects, and confirmatory factor analysis. Multivariable regression predicting ODI scores from PROMIS-29 domains was used to create a predictive equation. Predicted ODI scores were plotted against ODI scores to determine how well PROMIS-29 domains predicted ODI. RESULTS: Results showed good reliability and validity of PROMIS-29 in patients undergoing lumbar spine surgery: convergent and discriminant validity, low floor/ceiling effects, and unidimensional domains. The conversion equation used 6 PROMIS-29 domains (ODI% =  37.847- 1.475*[PFraw] + 1.842*[PAINraw] + 0.557*[SDraw] - 0.642*[SRraw] + 0.478*[PIraw] + 0.295*[DEPraw]). Correlation between the predicted and actual ODI scores was R = 0.88, R2 = 0.78, suggesting that the equation predicted ODI scores that are strongly correlated with actual ODI scores. CONCLUSIONS: Good measurement properties support the use of PROMIS-29 in spine surgery patients. Findings suggest accurate ODI scores can be derived from PROMIS-29 domains. Clinicians who want to move from ODI to PROMIS-29 can use this equation to obtain estimated ODI scores when only collecting PROMIS-29. These results support the idea that PROMIS-29 domains have the potential to replace disease-specific traditional PROMs.

A retrospective review comparing two-year patient-reported outcomes, costs, and healthcare resource utilization for TLIF vs. PLF for single-level degenerative spondylolisthesis.

PURPOSE: The purpose of this study was to compare patient-reported outcomes (PROs), morbidity, and costs of TLIF vs PLF to determine whether one treatment was superior in the setting of single-level degenerative spondylolisthesis. METHODS: Patients undergoing TLIF or PLF for single-level spondylolisthesis were included for retrospective analysis. EQ-5D, ODI, SF-12 MCS/PCS, NRS-BP/LP scores were collected at baseline and 24 months after surgery. 90-day post-operative complications, revision surgery rates, and satisfaction scores were also collected. Two-year resource use was multiplied by unit costs based on Medicare payment amounts (direct cost). Patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Total cost was used to assess mean total 2-year cost per QALYs gained after surgery. RESULTS: 62 and 37 patients underwent TLIF and PLF, respectively. Patients in the PLF group were older (p < 0.01). No significant differences were seen in baseline or 24-month PROs between the two groups. There was a significant improvement in all PROs from baseline to 24 months after surgery (p < 0.001). Both groups had similar rates of 90-day complications, revision surgery, satisfaction, and similar gain in QALYs and cost per QALYs gained. There was no significant difference in 24-month direct, indirect, and total cost. CONCLUSIONS: Overall costs and health care utilization were similar in both the groups. Both TLIF and PLF for single-level degenerative spondylolisthesis provide improvement in disability, pain, quality of life, and general health.

A predictive model and nomogram for predicting return to work at 3 months after cervical spine surgery: an analysis from the Quality Outcomes Database.

OBJECTIVEBack pain and neck pain are two of the most common causes of work loss due to disability, which poses an economic burden on society. Due to recent changes in healthcare policies, patient-centered outcomes including return to work have been increasingly prioritized by physicians and hospitals to optimize healthcare delivery. In this study, the authors used a national spine registry to identify clinical factors associated with return to work at 3 months among patients undergoing a cervical spine surgery.METHODSThe authors queried the Quality Outcomes Database registry for information collected from April 2013 through March 2017 for preoperatively employed patients undergoing cervical spine surgery for degenerative spine disease. Covariates included demographic, clinical, and operative variables, and baseline patient-reported outcomes. Multiple imputations were used for missing values and multivariable logistic regression analysis was used to identify factors associated with higher odds of returning to work. Bootstrap resampling (200 iterations) was used to assess the validity of the model. A nomogram was constructed using the results of the multivariable model.RESULTSA total of 4689 patients were analyzed, of whom 82.2% (n = 3854) returned to work at 3 months postoperatively. Among previously employed and working patients, 89.3% (n = 3443) returned to work compared to 52.3% (n = 411) among those who were employed but not working (e.g., were on a leave) at the time of surgery (p < 0.001). On multivariable logistic regression the authors found that patients who were less likely to return to work were older (age > 56-65 years: OR 0.69, 95% CI 0.57-0.85, p < 0.001; age > 65 years: OR 0.65, 95% CI 0.43-0.97, p = 0.02); were employed but not working (OR 0.24, 95% CI 0.20-0.29, p < 0.001); were employed part time (OR 0.56, 95% CI 0.42-0.76, p < 0.001); had a heavy-intensity (OR 0.42, 95% CI 0.32-0.54, p < 0.001) or medium-intensity (OR 0.59, 95% CI 0.46-0.76, p < 0.001) occupation compared to a sedentary occupation type; had workers' compensation (OR 0.38, 95% CI 0.28-0.53, p < 0.001); had a higher Neck Disability Index score at baseline (OR 0.60, 95% CI 0.51-0.70, p = 0.017); were more likely to present with myelopathy (OR 0.52, 95% CI 0.42-0.63, p < 0.001); and had more levels fused (3-5 levels: OR 0.46, 95% CI 0.35-0.61, p < 0.001). Using the multivariable analysis, the authors then constructed a nomogram to predict return to work, which was found to have an area under the curve of 0.812 and good validity.CONCLUSIONSReturn to work is a crucial outcome that is being increasingly prioritized for employed patients undergoing spine surgery. The results from this study could help surgeons identify at-risk patients so that preoperative expectations could be discussed more comprehensively.

Defining the minimum clinically important difference for grade I degenerative lumbar spondylolisthesis: insights from the Quality Outcomes Database.

OBJECTIVE Patient-reported outcomes (PROs) play a pivotal role in defining the value of surgical interventions for spinal disease. The concept of minimum clinically important difference (MCID) is considered the new standard for determining the effectiveness of a given treatment and describing patient satisfaction in response to that treatment. The purpose of this study was to determine the MCID associated with surgical treatment for degenerative lumbar spondylolisthesis. METHODS The authors queried the Quality Outcomes Database registry from July 2014 through December 2015 for patients who underwent posterior lumbar surgery for grade I degenerative spondylolisthesis. Recorded PROs included scores on the Oswestry Disability Index (ODI), EQ-5D, and numeric rating scale (NRS) for leg pain (NRS-LP) and back pain (NRS-BP). Anchor-based (using the North American Spine Society satisfaction scale) and distribution-based (half a standard deviation, small Cohen's effect size, standard error of measurement, and minimum detectable change [MDC]) methods were used to calculate the MCID for each PRO. RESULTS A total of 441 patients (80 who underwent laminectomies alone and 361 who underwent fusion procedures) from 11 participating sites were included in the analysis. The changes in functional outcome scores between baseline and the 1-year postoperative evaluation were as follows: 23.5 ± 17.4 points for ODI, 0.24 ± 0.23 for EQ-5D, 4.1 ± 3.5 for NRS-LP, and 3.7 ± 3.2 for NRS-BP. The different calculation methods generated a range of MCID values for each PRO: 3.3-26.5 points for ODI, 0.04-0.3 points for EQ-5D, 0.6-4.5 points for NRS-LP, and 0.5-4.2 points for NRS-BP. The MDC approach appeared to be the most appropriate for calculating MCID because it provided a threshold greater than the measurement error and was closest to the average change difference between the satisfied and not-satisfied patients. On subgroup analysis, the MCID thresholds for laminectomy-alone patients were comparable to those for the patients who underwent arthrodesis as well as for the entire cohort. CONCLUSIONS The MCID for PROs was highly variable depending on the calculation technique. The MDC seems to be a statistically and clinically sound method for defining the appropriate MCID value for patients with grade I degenerative lumbar spondylolisthesis. Based on this method, the MCID values are 14.3 points for ODI, 0.2 points for EQ-5D, 1.7 points for NRS-LP, and 1.6 points for NRS-BP.

Cost-utility of osteoarticular allograft versus endoprosthetic reconstruction for primary bone sarcoma of the knee: A markov analysis.

BACKGROUND: The most cost-effective reconstruction after resection of bone sarcoma is unknown. The goal of this study was to compare the cost effectiveness of osteoarticular allograft to endoprosthetic reconstruction of the proximal tibia or distal femur. METHODS: A Markov model was used. Revision and complication rates were taken from existing studies. Costs were based on Medicare reimbursement rates and implant prices. Health-state utilities were derived from the Health Utilities Index 3 survey with additional assumptions. Incremental cost-effectiveness ratios (ICER) were used with less than $100 000 per quality-adjusted life year (QALY) considered cost-effective. Sensitivity analyses were performed for comparison over a range of costs, utilities, complication rates, and revisions rates. RESULTS: Osteoarticular allografts, and a 30% price-discounted endoprosthesis were cost-effective with ICERs of $92.59 and $6 114.77. One-way sensitivity analysis revealed discounted endoprostheses were favored if allografts cost over $21 900 or endoprostheses cost less than $51 900. Allograft reconstruction was favored over discounted endoprosthetic reconstruction if the allograft complication rate was less than 1.3%. Allografts were more cost-effective than full-price endoprostheses. CONCLUSIONS: Osteoarticular allografts and price-discounted endoprosthetic reconstructions are cost-effective. Sensitivity analysis, using plausible complication and revision rates, favored the use of discounted endoprostheses over allografts. Allografts are more cost-effective than full-price endoprostheses.

The effect of NSAIDs on spinal fusion: a cross-disciplinary review of biochemical, animal, and human studies.

PURPOSE: Non-steroidal anti-inflammatory drugs (NSAIDs) play an important role in postoperative pain management. However, their use in the setting of spine fusion surgery setting has long been a topic of controversy. In this review we examined relevant research, including in vivo, animal, and clinical human studies, with the aim of understanding the effect of NSAIDs on spinal fusion. STUDY DESIGN/SETTING: Systematic review of study designs of all types from randomized controlled trials and meta-analyses to single-institution retrospective reviews. METHODS: A search of PubMed and Embase was conducted using the keywords: "spine," "spinal fracture," NSAIDs, anti-inflammatory non-steroidal agents, bone, bone healing, fracture, fracture healing, yielding a total of 110 studies. Other 28 studies were identified by cross-referencing, resulting in total 138 studies. RESULTS: There is no level I evidence from human studies regarding the use of NSAIDs on spinal fusion rates. The overall tone of the spine literature in the early 2000s was that NSAIDs increased the rate of non-union; however, nearly all human studies published after 2005 suggest that short-term (<2 weeks) postoperative use have no such effect. The dose dependency that is seen with a 2-week postoperative course is not present when NSAIDs are only used for 48 h after surgery. CONCLUSIONS: NSAID appear to have dose-dependent and duration-dependent effects on fusion rates. The short-term use of low-dose NSAIDs around the time of spinal fusion surgery is reasonable. Spine surgeons can consider the incorporation of NSAIDs into pain control regimens for spinal fusion patients with the goal of improving pain control and reducing the costs and complications associated with opioids.

Impact of old age on patient-report outcomes and cost utility for anterior cervical discectomy and fusion surgery for degenerative spine disease.

PURPOSE: With growing older population and increasing rates of cervical spinal surgery, it is vital to understand the value of cervical surgery in this population. We set forth to determine the cost utility following anterior cervical decompression and fusion (ACDF) for degenerative disease in older patients. METHODS: Patients undergoing ACDF for degenerative diseases were enrolled into prospective longitudinal registry. Patient-reported outcomes (PROs) were recorded at baseline, 1-year, and 2-year postoperatively. Two-year medical resource utilization, missed work, and health-state values [quality-adjusted life years (QALYs)] were assessed to compute cost per QALY gained. Patients were dichotomized based on age: <65 years (younger) and ≥65 years (older) to compare the cost utility in these age groups. RESULTS: Total 218 (87%) younger patients and 33 (13%) older patients who underwent ACDF were analyzed. Both the groups demonstrated a significant improvement in PROs 2-year following surgery. The older patients had a lower mean cumulative gain in QALYs compared to younger patients at 1 year (0.141 vs. 0.28, P = 0.05) and 2 years (0.211 vs. 0.424, P = 0.04). There was no significant difference in the mean total 2-year cost between older [$21,041 (95% CI $18,466-$23,616)] and younger [$22,669 (95% CI $$21,259-$24,079)] patients (P = 0.27). Two-year cost per QALY gained in older vs. younger patients was ($99,720/QALYs gained vs. ($53,464/QALYs gained, P = 0.68). CONCLUSION: ACDF surgery provided a significant gain in health-state utility in older patients with degenerative cervical pathology, with a mean cumulative 2-year cost per QALY gained of $99,720/QALY. While older patients have a slightly higher cost utility compared to their younger counterparts, surgery in the older cohort does provide a significant improvement in pain, disability, and quality-of-life outcomes.

Minimally invasive versus open fusion for Grade I degenerative lumbar spondylolisthesis: analysis of the Quality Outcomes Database.

OBJECTIVE Lumbar spondylolisthesis is a degenerative condition that can be surgically treated with either open or minimally invasive decompression and instrumented fusion. Minimally invasive surgery (MIS) approaches may shorten recovery, reduce blood loss, and minimize soft-tissue damage with resultant reduced postoperative pain and disability. METHODS The authors queried the national, multicenter Quality Outcomes Database (QOD) registry for patients undergoing posterior lumbar fusion between July 2014 and December 2015 for Grade I degenerative spondylolisthesis. The authors recorded baseline and 12-month patient-reported outcomes (PROs), including Oswestry Disability Index (ODI), EQ-5D, numeric rating scale (NRS)-back pain (NRS-BP), NRS-leg pain (NRS-LP), and satisfaction (North American Spine Society satisfaction questionnaire). Multivariable regression models were fitted for hospital length of stay (LOS), 12-month PROs, and 90-day return to work, after adjusting for an array of preoperative and surgical variables. RESULTS A total of 345 patients (open surgery, n = 254; MIS, n = 91) from 11 participating sites were identified in the QOD. The follow-up rate at 12 months was 84% (83.5% [open surgery]; 85% [MIS]). Overall, baseline patient demographics, comorbidities, and clinical characteristics were similarly distributed between the cohorts. Two hundred fifty seven patients underwent 1-level fusion (open surgery, n = 181; MIS, n = 76), and 88 patients underwent 2-level fusion (open surgery, n = 73; MIS, n = 15). Patients in both groups reported significant improvement in all primary outcomes (all p < 0.001). MIS was associated with a significantly lower mean intraoperative estimated blood loss and slightly longer operative times in both 1- and 2-level fusion subgroups. Although the LOS was shorter for MIS 1-level cases, this was not significantly different. No difference was detected with regard to the 12-month PROs between the 1-level MIS versus the 1-level open surgical groups. However, change in functional outcome scores for patients undergoing 2-level fusion was notably larger in the MIS cohort for ODI (-27 vs -16, p = 0.1), EQ-5D (0.27 vs 0.15, p = 0.08), and NRS-BP (-3.5 vs -2.7, p = 0.41); statistical significance was shown only for changes in NRS-LP scores (-4.9 vs -2.8, p = 0.02). On risk-adjusted analysis for 1-level fusion, open versus minimally invasive approach was not significant for 12-month PROs, LOS, and 90-day return to work. CONCLUSIONS Significant improvement was found in terms of all functional outcomes in patients undergoing open or MIS fusion for lumbar spondylolisthesis. No difference was detected between the 2 techniques for 1-level fusion in terms of patient-reported outcomes, LOS, and 90-day return to work. However, patients undergoing 2-level MIS fusion reported significantly better improvement in NRS-LP at 12 months than patients undergoing 2-level open surgery. Longer follow-up is needed to provide further insight into the comparative effectiveness of the 2 procedures.

Preoperative and surgical factors associated with postoperative intensive care unit admission following operative treatment for degenerative lumbar spine disease.

PURPOSE: Evaluate the factors associated with postoperative ICU admission in patients undergoing surgical management of degenerative lumbar spine disease. METHODS: Patients undergoing surgery for degenerative lumbar spine disease were enrolled into a prospective registry over a 2-year period. Preoperative variables (age, gender, ASA grade, ODI%, CAD, HTN, MI, CHF, DM, BMI, depression, anxiety) and surgical variables (instrumentation, arthrodesis, estimated blood loss, length of surgery) were collected prospectively. Postoperative ICU admission details were retrospectively determined from the electronic medical record. Student's t test (continuous variables) and Chi-square test (categorical variables) were used to determine the association of each preoperative and surgical variable with ICU admission. RESULTS: 808 Patients (273 laminectomy, 535 laminectomy and fusion) were evaluated. Forty-one (5.1%) patients were found to have postoperative ICU admissions. Reasons for admission included blood loss (12.2%), cardiac (29.3%), respiratory (19.5%), neurologic (31.7%), and other (7.3%). For preoperative variables, female gender (P < 0.001), history of CAD (P = 0.003), history of MI (P = 0.008), history of CHF (P = 0.001), age (P = 0.025), and ASA grade (P = 0.008) were significantly associated with ICU admission. For surgical variables, estimated blood loss (P < 0.001) and length of surgery (P < 0.001) were significantly associated with ICU admission. CONCLUSIONS: Age, female gender, ASA grade, cardiac comorbidities, intraoperative blood loss, and length of surgery were associated with increased risk of postoperative ICU admission. Knowledge of these factors can aid surgeons in patient selection and preoperative discussion with patients about potential need for unexpected admission to the ICU.

Can facet joint fluid on MRI and dynamic instability be a predictor of improvement in back pain following lumbar fusion for degenerative spondylolisthesis?

PURPOSE: To investigate the relationship between lumbar facet fluid and dynamic instability in degenerative spondylolisthesis (DS), as well as the relationship between facet fluid and patient-reported outcomes following a posterior lumbar fusion. METHODS: We analyzed consecutive patients with degenerative spondylolisthesis undergoing single level posterior lumbar fusion from December 2010 to January 2013 at a single academic institution. We investigated the relationship between fluid in the facet joint as measured on axial MRI and the presence of dynamic instability. We investigated the impact of facet fluid, Modic changes, and dynamic instability on patient-reported outcomes. RESULTS: There was a significant association between the amount of facet joint fluid and the presence of dynamic instability (p = 0.03); as facet fluid increases, the probability of dynamic instability also increases. For every 1 mm of facet fluid, there was a 41.6 % increase (95 % CI 1.8-97) in the odds of dynamic instability. A facet fluid amount less than 0.5 mm gave a 90 % probability that there was no dynamic instability. The presence of facet fluid and dynamic instability were associated with achieving minimal clinical important difference (MCID) in low back pain following lumbar fusion (p = 0.04 and 0.05, respectively). CONCLUSION: Facet joint fluid is associated with the presence of dynamic instability in DS. The presence of facet fluid and dynamic instability may predict increased likelihood of achieving MCID for improvement in back pain following posterior lumbar fusion.

Is obesity associated with worse patient-reported outcomes following lumbar surgery for degenerative conditions?

PURPOSE: To investigate whether obesity is associated with worse patient-reported outcomes following surgery for degenerative lumbar conditions. METHODS: We evaluated consecutive patients undergoing elective lumbar laminectomy or laminectomy with fusion for degenerative lumbar conditions. The Oswestry Disability Index (ODI), EuroQol-5D (EQ-5D), Short-Form 12 (SF-12), and NASS patient satisfaction were utilized. Chi-square tests and student t test assessed the association of obesity with PROs. Multivariate regression controlled for age, sex, smoking status, anxiety, depression, revision, preoperative narcotic use, payer status, and diabetes. RESULTS: A total of 602 patients were included. All PROs improved significantly in both groups. BMI ≥35 was associated with increased ODI at baseline (50.6 vs. 47.2 %, p = 0.012) and 12 months (30.5 vs. 25.7 %, p = 0.005). There was no difference in ODI change scores (21.2 vs. 19.4 %, p = 0.32). With multivariate analysis, BMI ≥35 was not predictive of worse ODI at 12 months (correlation coefficient 1.23, 95 % CI -0.225 to 2.676.) There was no significant difference between groups in percentage of patients achieving the minimum clinically important difference for ODI (59.6 vs. 64 %, p = 0.46) or patient satisfaction (80.5 vs. 78.9 %, p = 0.63). CONCLUSIONS: Body mass index ≥35 is associated with worse baseline and 12-month PROs, however, there was no difference in change scores across BMI groups. Controlling for important co-variables, BMI greater than 35 was not an independent predictor of worse PROs at 12 months.

Pain Sensitivity and Pain Catastrophizing Are Associated With Persistent Pain and Disability After Lumbar Spine Surgery.

OBJECTIVE: To examine whether pain sensitivity and pain catastrophizing are associated with persistent pain and disability after lumbar spine surgery. DESIGN: Prospective observational cohort study. SETTING: Academic medical center. PARTICIPANTS: Patients (N=68; mean age, 57.9±13.1y; 40 women [58.8%]) undergoing spine surgery for a degenerative condition from March 1, 2012 to April 30, 2013 were assessed 6 weeks, 3 months, and 6 months after surgery. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The main outcome measures were persistent back pain intensity, pain interference, and disability. Patients with persistent back pain intensity, pain interference, or disability were identified as those patients reporting Brief Pain Inventory scores ≥4 and Oswestry Disability Index scores ≥21 at all postoperative time points. RESULTS: From 6 weeks to 6 months after surgery, approximately 12.9%, 24.2%, and 46.8% of patients reported persistent back pain intensity, pain interference, or disability, respectively. Increased pain sensitivity at 6 weeks was associated with having persistent back pain intensity (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.0-4.1) after surgery. Increased pain catastrophizing at 6 weeks was associated with having persistent back pain intensity (OR, 1.1; 95% CI, 1.0-1.2), pain interference (OR, 1.1; 95% CI, 1.0-1.2), and disability (OR, 1.3; 95% CI, 1.1-1.4). An interaction effect was not found between pain sensitivity and pain catastrophizing on persistent outcomes (P>.05). CONCLUSIONS: The findings suggest the importance of early postoperative screening for pain sensitivity and pain catastrophizing to identify patients at risk for poor postoperative pain intensity, pain interference, and/or disability outcomes. Future research should consider the benefit of targeted therapeutic strategies for patients with these postoperative prognostic factors.

Characterization of symptomatic lumbar foraminal stenosis by conventional imaging.

PURPOSE: The preoperative identification of lumbar foraminal stenosis (LSFS) is important because a lack of recognition of this clinical entity is often associated with failed back surgery syndrome. Although magnetic resonance imaging (MRI) is widely used, and is considered by many as an appropriate tool for studying spine pathologies, there is limited data to suggest that MRI examinations are sufficiently sensitive or specific for the diagnosis of LSFS. There is a paucity of literature on the diagnostic performance of the combination of conventional diagnostic imaging methods. The purpose of this study is to determine the characteristics of conventional diagnostic imaging for symptomatic lumbar foraminal stenosis. METHODS: The characteristics of conventional diagnostic imaging of LSFS (X-ray, computed tomography (CT) and MRI) were assessed in 68 patients in whom the site of the stenosis was confirmed by means of selective decompression surgeries. RESULTS: Measurement of the foraminal width and height on CT imaging of the diseased side was significantly less than that on the intact side in the LSFS group. The grading scale for facet joint arthritis on the diseased side was significantly higher than that on the intact side in the LSFS group. The prevalence of the vacuum phenomenon and stage of intervertebral disk (IVD) pathology were higher in the L5-S1 spine of the LSFS group (95.2%) compared with the lumbar spinal canal stenosis (LCS) group (21.1%). MRI study revealed that the prevalence of Type 3 Modic changes was significantly higher in the LSFS group (39.3%) compared with the LCS group (7.7%). CONCLUSIONS: Our study demonstrates combination of conventional imaging techniques, to improve the detection of symptomatic foraminal stenosis.

Prediction model for outcome after low-back surgery: individualized likelihood of complication, hospital readmission, return to work, and 12-month improvement in functional disability.

OBJECT Lumbar spine surgery has been demonstrated to be efficacious for many degenerative spine conditions. However, there is wide variability in outcome after spine surgery at the individual patient level. All stakeholders in spine care will benefit from identification of the unique patient or disease subgroups that are least likely to benefit from surgery, are prone to costly complications, and have increased health care utilization. There remains a large demand for individual patient-level predictive analytics to guide decision support to optimize outcomes at the patient and population levels. METHODS One thousand eight hundred three consecutive patients undergoing spine surgery for various degenerative lumbar diagnoses were prospectively enrolled and followed for 1 year. A comprehensive patient interview and health assessment was performed at baseline and at 3 and 12 months after surgery. All predictive covariates were selected a priori. Eighty percent of the sample was randomly selected for model development, and 20% for model validation. Linear regression was performed with Bayesian model averaging to model 12-month ODI (Oswestry Disability Index). Logistic regression with Bayesian model averaging was used to model likelihood of complications, 30-day readmission, need for inpatient rehabilitation, and return to work. Goodness-of-fit was assessed via R(2) for 12-month ODI and via the c-statistic, area under the receiver operating characteristic curve (AUC), for the categorical endpoints. Discrimination (predictive performance) was assessed, using R(2) for the ODI model and the c-statistic for the categorical endpoint models. Calibration was assessed using a plot of predicted versus observed values for the ODI model and the Hosmer-Lemeshow test for the categorical endpoint models. RESULTS On average, all patient-reported outcomes (PROs) were improved after surgery (ODI baseline vs 12 month: 50.4 vs 29.5%, p < 0.001). Complications occurred in 121 patients (6.6%), 108 (5.9%) were readmitted within 30 days of surgery, 188 (10.3%) required discharge to inpatient rehabilitation, 1630 (88.9%) returned to work, and 449 (24.5%) experienced an unplanned outcome (no improvement in ODI, a complication, or readmission). There were 45 unique baseline variable inputs, derived from 39 clinical variables and 38 questionnaire items (ODI, SF-12, MSPQ, VAS-BP, VAS-LP, VAS-NP), included in each model. For prediction of 12-month ODI, R(2) was 0.51 for development and 0.47 for the validation study. For prediction of a complication, readmission, inpatient rehabilitation, and return to work, AUC values ranged 0.72-0.84 for development and 0.79-0.84 for validation study. CONCLUSIONS A novel prediction model utilizing both clinical data and patient interview inputs explained the majority of variation in outcome observed after lumbar spine surgery and reliably predicted 12-month improvement in physical disability, return to work, major complications, readmission, and need for inpatient rehabilitation for individual patients. Application of these models may allow clinicians to offer spine surgery specifically to those who are most likely to benefit and least likely to incur complications and excess costs.

Patient-reported outcomes 3 months after spine surgery: is it an accurate predictor of 12-month outcome in real-world registry platforms?

OBJECT The health care landscape is rapidly shifting to incentivize quality of care rather than quantity of care. Quality and outcomes registry platforms lie at the center of all emerging evidence-driven reform models and will be used to inform decision makers in health care delivery. Obtaining real-world registry outcomes data from patients 12 months after spine surgery remains a challenge. The authors set out to determine whether 3-month patient-reported outcomes accurately predict 12-month outcomes and, hence, whether 3-month measurement systems suffice to identify effective versus noneffective spine care. METHODS All patients undergoing lumbar spine surgery for degenerative disease at a single medical institution over a 2-year period were enrolled in a prospective longitudinal registry. Patient-reported outcome instruments (numeric rating scale [NRS], Oswestry Disability Index [ODI], 12-Item Short Form Health Survey [SF-12], EQ-5D, and the Zung Self-Rating Depression Scale) were recorded prospectively at baseline and at 3 months and 12 months after surgery. Linear regression was performed to determine the independent association of 3- and 12-month outcome. Receiver operating characteristic (ROC) curve analysis was performed to determine whether improvement in general health state (EQ-5D) and disability (ODI) at 3 months accurately predicted improvement and achievement of minimum clinical important difference (MCID) at 12 months. RESULTS A total of 593 patients undergoing elective lumbar surgery were included in the study. There was a significant correlation between 3-month and 12-month EQ-5D (r = 0.71; p < 0.0001) and ODI (r = 0.70; p < 0.0001); however, the authors observed a sizable discrepancy in achievement of a clinically significant improvement (MCID) threshold at 3 versus 12 months on an individual patient level. For postoperative disability (ODI), 11.5% of patients who achieved an MCID threshold at 3 months dropped below this threshold at 12 months; 10.5% of patients who did not meet the MCID threshold at 3 months continued to improve and ultimately surpassed the MCID threshold at 12 months. For ODI, achieving MCID at 3 months accurately predicted 12-month MCID with only 62.6% specificity and 86.8% sensitivity. For postoperative health utility (EQ-5D), 8.5% of patients lost an MCID threshold improvement from 3 months to 12 months, while 4.0% gained the MCID threshold between 3 and 12 months postoperatively. For EQ-5D (quality-adjusted life years), achieving MCID at 3 months accurately predicted 12-month MCID with only 87.7% specificity and 87.2% sensitivity. CONCLUSIONS In a prospective registry, patient-reported measures of treatment effectiveness obtained at 3 months correlated with 12-month measures overall in aggregate, but did not reliably predict 12-month outcome at the patient level. Many patients who do not benefit from surgery by 3 months do so by 12 months, and, conversely, many patients reporting meaningful improvement by 3 months report loss of benefit at 12 months. Prospective longitudinal spine outcomes registries need to span at least 12 months to identify effective versus noneffective patient care.

Quality analysis of anterior cervical discectomy and fusion in the outpatient versus inpatient setting: analysis of 7288 patients from the NSQIP database.

OBJECT In an era of escalating health care cost and universal pressure of improving efficiency and cost of care, ambulatory surgery centers (ASCs) have emerged as lower cost options for many surgical therapies. Anterior cervical discectomy and fusion (ACDF) is one of the most prevalent spine surgeries performed and is rapidly increasing with an expanding aging population. While ASCs offer cost advantages for ACDF, there is a scarcity of evidence that ASCs allow for equivalent quality and thus superior health care value. Therefore, the authors analyzed a nationwide, prospective quality improvement registry (National Surgical Quality Improvement Program [NSQIP]) to compare the quality of ACDF surgery performed in the outpatient ASC versus the inpatient hospital setting. METHODS Patients undergoing ACDF (2005-2011) were identified from the NSQIP database based on the primary Current Procedural Terminology codes. Patients were divided into 2 cohorts (outpatient vs inpatient) based on the acute care setting documented in the NSQIP database. All 30-day surgical morbidity and mortality rates were compared between the 2 groups. Propensity score matching and multivariate logistic regression analysis were used to adjust for confounding factors and to identify the independent association of outpatient ACDF with perioperative outcomes and morbidity. RESULTS A total of 7288 ACDF cases were identified (inpatient = 6120, outpatient = 1168). Unadjusted rates of major morbidity (0.94% vs 4.5%, p < 0.001) and return to the operating room (OR) within 30 days (0.3% vs 2.0%, p < 0.001) were significantly lower in outpatient versus inpatient ACDF. After propensity matching 1442 cases (inpatient = 650, outpatient = 792) based on baseline 32 covariates, rates of major morbidity (1.4% vs 3.1%, p = 0.03), and return to the OR (0.34% vs 1.4%, p = 0.04) remained significantly lower after outpatient ACDF. Adjusted comparison using multivariate logistic regression demonstrated that ACDF performed in the outpatient setting had 58% lower odds of having a major morbidity and 80% lower odds of return to the OR within 30 days. CONCLUSIONS An analysis of a nationwide, prospective quality improvement registry representing more than 250 hospitals demonstrates that 1- to 2-level ACDF can be safely performed in the outpatient ambulatory surgery setting in patients who are appropriate candidates. In an effort to decrease cost of care, surgeons can safely consider performing ACDF in an ASC environment.

Effect of complications within 90 days on patient-reported outcomes 3 months and 12 months following elective surgery for lumbar degenerative disease.

OBJECT There is a paradigm shift toward rewarding providers for quality rather than volume. Complications appear to occur at a fairly consistent frequency in large aggregate data sets. Understanding how complications affect long-term patient-reported outcomes (PROs) following degenerative lumbar surgery is vital. The authors hypothesized that 90-day complications would adversely affect long-term PROs. METHODS Nine hundred six consecutive patients undergoing elective surgery for degenerative lumbar disease over a period of 4 years were enrolled into a prospective longitudinal registry. The following PROs were recorded at baseline and 12-month follow-up: Oswestry Disability Index (ODI) score, numeric rating scales for back and leg pain, quality of life (EQ-5D scores), general physical and mental health (SF-12 Physical Component Summary [PCS] and Mental Component Summary [MCS] scores) and responses to the North American Spine Society (NASS) satisfaction questionnaire. Previously published minimum clinically important difference (MCID) threshold were used to define meaningful improvement. Complications were divided into major (surgicalsite infection, hardware failure, new neurological deficit, pulmonary embolism, hematoma and myocardial infarction) and minor (urinary tract infection, pneumonia, and deep venous thrombosis). RESULTS Complications developed within 90 days of surgery in 13% (118) of the patients (major in 12% [108] and minor in 8% [68]). The mean improvement in ODI scores, EQ-5D scores, SF-12 PCS scores, and satisfaction at 3 months after surgery was significantly less in the patients with complications than in those who did not have major complications (ODI: 13.5 ± 21.2 vs 21.7 ± 19, < 0.0001; EQ-5D: 0.17 ± 0.25 vs 0.23 ± 0.23, p = 0.04; SF-12 PCS: 8.6 ± 13.3 vs 13.0 ± 11.9, 0.001; and satisfaction: 76% vs 90%, p = 0.002). At 12 months after surgery, the patients with major complications had higher ODI scores than those without complications (29.1 ± 17.7 vs 25.3 ± 18.3, p = 0.02). However, there was no difference in the change scores in ODI and absolute scores across all other PROs between the 2 groups. In multivariable linear regression analysis, after controlling for an array of preoperative variables, the occurrence of a major complication was not associated with worsening ODI scores 12 months after surgery. There was no difference in the percentage of patients achieving the MCID for disability (66% vs 64%), back pain (55% vs 56%), leg pain (62% vs 59%), or quality of life (19% vs 14%) or in patient satisfaction rates (82% vs 80%) between those without and with major complications. CONCLUSIONS Major complications within 90 days following lumbar spine surgery have significant impact on the short-term PROs. Patients with complications, however, do eventually achieve clinically meaningful outcomes and report satisfaction equivalent to those without major complications. This information allows a physician to counsel patients on the fact that a complication creates frustration, cost, and inconvenience; however, it does not appear to adversely affect clinically meaningful long-term outcomes and satisfaction.