Clinical and Cost-Effectiveness of Lumbar Interbody Fusion Using Tritanium Posterolateral Cage (vs. Propensity-Matched Cohort of PEEK Cage)

Introduction

Surgical management of degenerative lumbar spine disorders is effective at improving patient pain, disability, and quality of life; however, obtaining a durable posterolateral fusion after decompression remains a challenge. Interbody fusion technologies are viable means of improving fusion rates in the lumbar spine, specifically various graft materials including autograft, structural allograft, titanium, and polyether ether ketone. This study assesses the effectiveness of Tritanium posterolateral cage in the treatment of degenerative disk disease.

Methods

Nearest-neighbor 1:1 matched control transforaminal lumbar interbody fusion with PEEK vs. Tritanium posterior lumbar (PL) cage interbody fusion patients were identified using propensity scoring from patients that underwent elective surgery for degenerative disk diseases. Line graphs were generated to compare the trajectories of improvement in patient-reported outcomes (PROs) from baseline to 3 and 12 months postoperatively. The nominal data were compared via the χ² test, while the continuous data were compared via Student's t-test.

Results

The two groups had no difference regarding either the 3- or 12-month Euro-Qol-5D (EQ-5D), numeric rating scale (NRS) leg pain, and NRS back pain; however, the Tritanium interbody cage group had better Oswestry Disability Index (ODI) scores compared to the control group of the PEEK interbody cage at both 3 and 12 months (p=0.013 and 0.048).

Conclusions

Our results indicate the Tritanium cage is an effective alternative to the previously used PEEK cage in terms of PROs, surgical safety, and radiological parameters of surgical success. The Tritanium cohort showed better ODI scores, higher fusion rates, lower subsidence, and lower indirect costs associated with surgical management, when compared to the propensity-matched PEEK cohort.

What Are the Primary Cues Used by Mammalian Predators to Locate Freshwater Turtle Nests? A Critical Review of the Evidence

Turtle biologists have long been interested in the biotic and abiotic factors that influence the detection of freshwater turtle nests by mammalian predators. Increased knowledge of nest predation dynamics may help develop conservation strategies to increase turtle nesting success by altering or reducing the signal strength of predominant nest location cues. However, despite this long-standing interest, the related research has produced inconsistent and sometimes conflicting results across studies. Here we review much of the existing literature on freshwater turtle nest predation by mammalian predators and attempt to synthesize some general, underlying themes. Available data suggest that raccoons (Procyon lotor) primarily use olfactory cues associated with nest cavity construction to locate turtle nests. However, some other predators, including red foxes (Vulpes vulpes) and other canids, may commonly use a wider array of cues, including scents from nesting turtles and their eggs as well as visual cues, while foraging. The literature also suggests that the length of the period turtle nests remain vulnerable to nest predation is dependent on the predator community, with raccoons exhibiting relatively short timelines relative to some other predators, including canids. This review has revealed a strong North American bias in published work, highlighting the need for additional studies of turtle nest predation dynamics in other areas of the world where chelonians are often imperiled elements of the biota.

A 3D-Printed Simulator and Teaching Module for Placing S2-Alar-Iliac Screws

BACKGROUND

The concept of the S2-alar-iliac (S2AI) screw was developed approximately one decade ago and has rapidly become an important component of spinal arthrodesis. Two challenges to placing S2AI screws are gaining an intuition for free-hand screw placement trajectory and acquisition of the appropriate radiograph to both guide screw placement and diagnose misplacement.

OBJECTIVE

To present the design and manufacture of an S2AI screw placement simulator and teaching module that addresses both challenges.

METHODS

This simulator involves using a 3D printer to create a life-sized pelvis. Participants first used this print to practice placing free-hand S2AI screws. Then participants used another print to practice taking radiographs showing the posterior superior iliac spine-anterior superior iliac spine corridor (teardrop) view.

RESULTS

The accuracy of screw placement increased from 17 to 80% on the left side and 7 to 100% on the right side. The number of radiographs taken by each participant to obtain the teardrop view decreased after practice with the simulator compared to baseline.

CONCLUSION

Practice with the S2AI simulator led to an improved intuition of an appropriate free-hand S2AI screw trajectory and a decrease in the number of radiographs needed for obtaining the correct diagnostic view.

Drivers of Variability in 90-Day Cost for Elective Laminectomy and Fusion for Lumbar Degenerative Disease

BACKGROUND

Considerable variability exists in the cost of surgery following spine surgery for common degenerative spine diseases. This variation in the cost of surgery can affect the payment bundling during the postoperative 90 d.

OBJECTIVE

To determine the drivers of variability in total 90-d cost for laminectomy and fusion surgery.

METHODS

A total of 752 patients who underwent elective laminectomy and fusion for degenerative lumbar conditions and were enrolled into a prospective longitudinal registry were included in the study. Total cost during the 90-d global period was derived as sum of cost of surgery, cost associated with postdischarge utilization. Multivariable regression models were built for total 90-d cost.

RESULTS

The mean 90-d direct cost was $29 295 (range, $28 612-$29 973). Based on our regression tree analysis, the following variables were found to drive the 90-d cost: age, BMI, gender, diagnosis, postop imaging, number of operated levels, ASA grade, hypertension, arthritis, preop and postop opioid use, length of hospital stay, duration of surgery, 90-d readmission, outpatient physical/occupational therapy, inpatient rehab, postop healthcare visits, postop nonopioid pain medication use nonsteroidal antiinflammatory drug (NSAIDs), and muscle relaxant use. The R2 for tree model was 0.64.

CONCLUSION

Utilizing prospectively collected data, we demonstrate that considerable variation exists in total 90-d cost, nearly 70% of which can be explained by those factors included in our modeling. Risk-adjusted payment schemes can be crafted utilizing the significant drivers presented here. Focused interventions to target some of the modifiable factors have potential to reduce cost and increase the value of care.

Initial Experience with Using a Structured Light 3D Scanner and Image Registration to Plan Bedside Subdural Evacuating Port System Placement

BACKGROUND

Chronic subdural hematoma evacuation can be achieved in select patients through bedside placement of the Subdural Evacuation Port System (SEPS; Medtronic, Inc., Dublin, Ireland). This procedure involves drilling a burr hole at the thickest part of the hematoma. Identifying this location is often difficult, given the variable tilt of available imaging and distant anatomic landmarks. This paper evaluates the feasibility and accuracy of a bedside navigation system that relies on visible light-based 3-dimensional (3D) scanning and image registration to a pre-procedure computed tomography scan. The information provided by this system may increase accuracy of the burr hole location.

METHODS

In Part 1, the accuracy of this system was evaluated using a rigid 3D printed phantom head with implanted fiducials. In Part 2, the navigation system was tested on 3 patients who underwent SEPS placement.

RESULTS

The error in registration of this system was less than 2.5 mm when tested on a rigid 3D printed phantom head. Fiducials located in the posterior aspect of the head were difficult to reliably capture. For the 3 patients who underwent 5 SEPS placements, the distance between anticipated SEPS burr hole location based on registration and actual burr hole location was less than 1cm.

CONCLUSIONS

A bedside cranial navigation system based on 3D scanning and image registration has been introduced. Such a system may increase the success rate of bedside procedures, such as SEPS placement. However, technical challenges such as the ability to scan hair and practical challenges such as minimization of patient movement during scans must be overcome.

Unique osmoregulatory morphology in primitive sharks: an intermediate state between holocephalan and derived shark secretory morphology

Discovery of an unusual rectal gland in the Atlantic sixgill shark Hexanchus vitulus led us to examine the rectal glands of 31 species of sharks to study diversity in rectal-gland morphology. Twenty-four of 31 species of sharks had digitiform glands (mean width-length ratio ± SD = 0.17 ± 0.04) previously assumed to be characteristic of all elasmobranchs regardless of habitat depth or phylogenetic age. Rectal glands from the family Somniosidae were kidney bean-shaped (mean width: length ± SD = 0.46 ± 0.05); whereas those from families Echinorhinidae and Hexanchidae were lobulate (mean width: length ± SD = 0.55 ± 0.06). Rectal gland width: length were different among species with digitiform morphology and lobulate morphology (ANOVA; R² = 0.9; df = 15, 386; 401, F = 219.24; P < 0.001). Histological and morphological characteristics of the digitiform morphology from deep-sea sharks were similar to those from shallow-water sharks. Histology of lobulate rectal glands from hexanchids were characterised by tubule bundles separated by smooth muscle around a central lumen. Additionally, we examined plasma chemistry of four species of sharks with digitiform rectal glands and two species with lobulate rectal-gland morphology to see if there were differences between morphologies. Plasma chemistry analysis showed that urea and trimethylamine N-oxide (TMAO) followed the piezolyte hypothesis, with TMAO being highest and urea being lowest in deep-sea sharks. Among electrolytes, Na⁺ was highest in species with lobulate rectal glands. Hexanchids and echinorhinids both have lobulate rectal glands similar to those of holocephalans, despite the more than 400 million years separating these two groups. The morphological similarities between the lobulate rectal-gland anatomy of primitive sharks and the secretory morphology of holocephalans may represent an intermediate state between Holocephali and derived shark species.

Drivers of Variability in 90-Day Cost for Elective Anterior Cervical Discectomy and Fusion for Cervical Degenerative Disease

BACKGROUND

Value-based episode of care reimbursement models is being investigated to curb unsustainable health care costs. Any variation in the cost of index spine surgery can affect the payment bundling during the 90-d global period.

OBJECTIVE

To determine the drivers of variability in cost for patients undergoing elective anterior cervical discectomy and fusion (ACDF) for degenerative cervical spine disease.

METHODS

Four hundred forty-five patients undergoing elective ACDF for cervical spine degenerative diagnoses were included in the study. The direct 90-d cost was derived as sum of cost of surgery, cost associated with postdischarge utilization. Multiple variable linear regression models were built for total 90-d cost.

RESULTS

The mean 90-d direct cost was $17685 ± $5731. In a multiple variable linear regression model, the length of surgery, number of levels involved, length of hospital stay, preoperative history of anticoagulation medication, health-care resource utilization including number of imaging, any complications and readmission encounter were the significant contributor to the 90-d cost. The model performance as measured by R2 was 0.616.

CONCLUSION

There was considerable variation in total 90-d cost for elective ACDF surgery. Our model can explain about 62% of these variations in 90-d cost. The episode of care reimbursement models needs to take into account these variations and be inclusive of the factors that drive the variation in cost to develop a sustainable payment model. The generalized applicability should take in to account the differences in patient population, surgeons' and institution-specific differences.

Development and validation of a predictive model for 90-day readmission following elective spine surgery

OBJECTIVE

Hospital readmissions lead to a significant increase in the total cost of care in patients undergoing elective spine surgery. Understanding factors associated with an increased risk of postoperative readmission could facilitate a reduction in such occurrences. The aims of this study were to develop and validate a predictive model for 90-day hospital readmission following elective spine surgery.

METHODS

All patients undergoing elective spine surgery for degenerative disease were enrolled in a prospective longitudinal registry. All 90-day readmissions were prospectively recorded. For predictive modeling, all covariates were selected by choosing those variables that were significantly associated with readmission and by incorporating other relevant variables based on clinical intuition and the Akaike information criterion. Eighty percent of the sample was randomly selected for model development and 20% for model validation. Multiple logistic regression analysis was performed with Bayesian model averaging (BMA) to model the odds of 90-day readmission. Goodness of fit was assessed via the C-statistic, that is, the area under the receiver operating characteristic curve (AUC), using the training data set. Discrimination (predictive performance) was assessed using the C-statistic, as applied to the 20% validation data set.

RESULTS

A total of 2803 consecutive patients were enrolled in the registry, and their data were analyzed for this study. Of this cohort, 227 (8.1%) patients were readmitted to the hospital (for any cause) within 90 days postoperatively. Variables significantly associated with an increased risk of readmission were as follows (OR [95% CI]): lumbar surgery 1.8 [1.1–2.8], government-issued insurance 2.0 [1.4–3.0], hypertension 2.1 [1.4–3.3], prior myocardial infarction 2.2 [1.2–3.8], diabetes 2.5 [1.7–3.7], and coagulation disorder 3.1 [1.6–5.8]. These variables, in addition to others determined a priori to be clinically relevant, comprised 32 inputs in the predictive model constructed using BMA. The AUC value for the training data set was 0.77 for model development and 0.76 for model validation.

CONCLUSIONS

Identification of high-risk patients is feasible with the novel predictive model presented herein. Appropriate allocation of resources to reduce the postoperative incidence of readmission may reduce the readmission rate and the associated health care costs.

Healthcare Resource Utilization and Patient-Reported Outcomes Following Elective Surgery for Intradural Extramedullary Spinal Tumors

BACKGROUND

Healthcare resource utilization and patient-reported outcomes (PROs) for intradural extramedullary (IDEM) spine tumors are not well reported.

OBJECTIVE

To analyze the PROs, costs, and resource utilization 1 year following surgical resection of IDEM tumors.

METHODS

Patients undergoing elective spine surgery for IDEM tumors and enrolled in a single-center, prospective, longitudinal registry were analyzed. Baseline and postoperative 1-year PROs were recorded. One-year spine-related direct and indirect healthcare resource utilization was assessed. One-year resource use was multiplied by unit costs based on Medicare national payment amounts (direct cost). Patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost).

RESULTS

A total of 38 IDEM tumor patients were included in this analysis. There was significant improvement in quality of life (EuroQol-5D), disability (Oswestry and Neck Disability Indices), pain (Numeric rating scale pain scores for back/neck pain and leg/arm pain), and general physical and mental health (Short-form-12 health survey, physical and mental component scores) in both groups 1 year after surgery (P < .0001). Eighty-seven percent (n = 33) of patients were satisfied with surgery. The 1-year postdischarge resource utilization including healthcare visits, medication, and diagnostic cost was $4111 ± $3596. The mean total direct cost was $23 717 ± $7412 and indirect cost was $5544 ± $4336, resulting in total 1-year cost $29 177 ± $9314.

CONCLUSION

Surgical resection of the IDEM provides improvement in patient-reported quality of life, disability, pain, general health, and satisfaction at 1 year following surgery. Furthermore, we report the granular costs of surgical resection and healthcare resource utilization in this population.

Timing of Operative Intervention in Traumatic Spine Injuries Without Neurological Deficit

BACKGROUND

Numerous studies have demonstrated the benefits of early decompression and stabilization in unstable spine injuries with incomplete neurological deficits. However, a clear consensus on timing to operative intervention still does not exist in those with a normal neurological exam and unstable spine.

OBJECTIVE

To determine the optimal timing of operative intervention in traumatic spine injuries without neurological deficit.

METHODS

Retrospective chart review at a single institution was performed including patients with traumatic spine injuries without neurological deficit admitted from December 2001 to August 2012. Estimated intraoperative blood loss (EBL), in-hospital complications, postoperative hospital length of stay (HLOS), intensive care unit length of stay (ICULOS), and ventilator days were recorded. Delayed surgery was defined as surgery 72 h after admission.

RESULTS

A total of 456 patients were included for analysis. There was a trend towards statistical significance between the time to operative intervention and EBL in bivariate analysis (P = .07). In the risk-adjusted multivariable analysis delayed vs early surgery was not associated with increased EBL or complications. Delayed surgery was associated with increased ICULOS (odds ratio [OR] = 2.19; 95% confidence interval [CI]: 1.38-3.51; P = .001), ventilator days (OR = 2.09; 95% CI: 1.28-3.43; P = .004), and increased postoperative HLOS (OR = 1.84; 95% CI: 1.22-2.76; P = .004).

CONCLUSION

Earlier operative intervention was associated with decreased ICULOS, ventilator days, and postoperative HLOS and did not show a statistically significant increase in EBL or complications. Earlier operative intervention for traumatic spine injuries without neurological deficit provides better outcomes compared to delayed surgery.

Bending the Cost Curve-Establishing Value in Spine Surgery

BACKGROUND

As publically promoted by all stakeholders in health care reform, prospective outcomes registry platforms lie at the center of all current evidence-driven value-based models.

OBJECTIVE

To demonstrate the variability in outcomes and cost at population level and individual patient level for patients undergoing spine surgery for degenerative diseases.

METHODS

Retrospective analysis of prospective longitudinal spine registry data was conducted. Baseline and postoperative 1-year patient-reported outcomes were recorded. Previously published minimal clinically important difference for Oswestry Disability Index (14.9) was used. Back-related resource utilization and quality-adjusted life years (QALYs) were assessed. Variations in outcomes and cost were analyzed at population level and at the individual patient level.

RESULTS

A total of 1454 patients were analyzed. There was significant improvement in patient-reported outcomes at postoperative 1 year ( P < .0001). For patients demonstrating health benefit at population level, 12.5%, n = 182 of patients experienced no gain from surgery and 38%, n = 554 failed to achieve minimal clinically important difference. Mean 1-year QALY-gained was 0.29; 18% of patients failed to report gain in QALY. For patients with 2-year follow-up, surgery resulted in 0.62 QALY-gained at average direct cost of $28 953. A wide variation in both QALY-gained and cost was observed.

CONCLUSION

Spine treatments that on average are cost-effective may have wide variability in value at the individual patient level. The variability demonstrated here represents an opportunity, through registries, to identify specific care that may be less effective, and refine patient-specific care delivery and indications to drive overall group-level treatment value. Understanding value of spine care at an individualized as well as population level will allow clinicians, and eventually payers, to better target resources for improving care for nonresponders, ultimately driving up the average health for the whole population.

An analysis from the Quality Outcomes Database, Part 2. Predictive model for return to work after elective surgery for lumbar degenerative disease

OBJECTIVE

Current costs associated with spine care are unsustainable. Productivity loss and time away from work for patients who were once gainfully employed contributes greatly to the financial burden experienced by individuals and, more broadly, society. Therefore, it is vital to identify the factors associated with return to work (RTW) after lumbar spine surgery. In this analysis, the authors used data from a national prospective outcomes registry to create a predictive model of patients’ ability to RTW after undergoing lumbar spine surgery for degenerative spine disease.

METHODS

Data from 4694 patients who underwent elective spine surgery for degenerative lumbar disease, who had been employed preoperatively, and who had completed a 3-month follow-up evaluation, were entered into a prospective, multicenter registry. Patient-reported outcomes—Oswestry Disability Index (ODI), numeric rating scale (NRS) for back pain (BP) and leg pain (LP), and EQ-5D scores—were recorded at baseline and at 3 months postoperatively. The time to RTW was defined as the period between operation and date of returning to work. A multivariable Cox proportional hazards regression model, including an array of preoperative factors, was fitted for RTW. The model performance was measured using the concordance index (c-index).

RESULTS

Eighty-two percent of patients (n = 3855) returned to work within 3 months postoperatively. The risk-adjusted predictors of a lower likelihood of RTW were being preoperatively employed but not working at the time of presentation, manual labor as an occupation, worker’s compensation, liability insurance for disability, higher preoperative ODI score, higher preoperative NRS-BP score, and demographic factors such as female sex, African American race, history of diabetes, and higher American Society of Anesthesiologists score. The likelihood of a RTW within 3 months was higher in patients with higher education level than in those with less than high school–level education. The c-index of the model’s performance was 0.71.

CONCLUSIONS

This study presents a novel predictive model for the probability of returning to work after lumbar spine surgery. Spine care providers can use this model to educate patients and encourage them in shared decision-making regarding the RTW outcome. This evidence-based decision support will result in better communication between patients and clinicians and improve postoperative recovery expectations, which will ultimately increase the likelihood of a positive RTW trajectory.

Is the use of minimally invasive fusion technologies associated with improved outcomes after elective interbody lumbar fusion? Analysis of a nationwide prospective patient-reported outcomes registry

BACKGROUND CONTEXT

Over the last decade, clinical investigators and biomedical industry groups have used significant resources to develop advanced technologies that enable less invasive spine fusions. These minimally invasive surgery (MIS) technologies often require increased expenditures by hospitals and payers. Although several small single center studies have suggested MIS technologies decrease surgical morbidity and reduce hospital stay, evidence documenting benefit from a patient perspective remains limited. Furthermore, MIS outcomes have yet to be evaluated from the perspective of multiple practice types representing the broad spectrum of US spine surgery.

PURPOSE

This study aimed to examine a population of patients who underwent one- or two-level interbody lumbar fusion diagnosed with lumbar stenosis or Grade 1 spondylolisthesis in an observational, prospective national registry for the purposes of determining how MIS and traditional open technologies affect postsurgical and patient-reported outcomes (PROs).

STUDY DESIGN/SETTING

This study used observational analysis of prospectively collected data.

PATIENT SAMPLE

The sample consisted of cases from the National Neurosurgery Quality and Outcomes Database (N²QOD).

OUTCOME MEASURES

Numeric rating scale for back and leg pain, Oswestry Disability Index, EuroQol-5D, return to work, and perioperative morbidity were the outcome measures.

METHODS

The N²QOD is a prospective PROs registry enrolling patients undergoing elective spine surgery from 60 hospitals in 27 US states via representative sampling. We analyzed the N²QOD aggregate dataset (2010-2014) to identify one- and two-level lumbar interbody fusion procedures performed for lumbar stenosis or Grade 1 spondylolisthesis with 12 months' follow-up where surgical instrumentation and implant types were clearly identified. Perioperative and 1-year outcomes were compared between cases performed with MIS enabling technologies versus traditional open technologies before and after propensity matching.

RESULTS

There were 467 (24%) patients who underwent elective interbody lumbar fusion using MIS enabling technologies whereas 1,480 (76%) underwent the procedure using traditional open technologies. The MIS patients were slightly healthier (American Society of Anesthesiologists grade), had private insurance more frequently, and underwent two-level fusion less frequently. Unmatched, the MIS cohort was associated with reduced blood loss, a 0.7-day reduction in mean length of hospital stay, and 5% reduced need for post-discharge inpatient rehabilitation, but equivalent 90-day safety measures. After propensity matching, the MIS cohort remained associated with reduced blood loss and a shorter length of stay for one-level fusion (p<.05) but had equivalent length of stay for two-level fusion. Outcomes in all other 90-day safety measures were similar. In both unadjusted and propensity-matched comparison, MIS versus open technologies were associated with equivalent return to work, patient-reported pain, physical disability, and quality of life at 3 and 12 months' follow-up.

CONCLUSIONS

In a representative sampling registry of elective interbody lumbar spine fusion procedures spanning 27 US states, nearly a quarter of procedures performed from 2010 to 2014 used minimally invasive enabling technologies. Regardless of approach, interbody lumbar fusion was associated with significant and sustained improvements in all measured health domains. When used in everyday care by a wide spectrum of spine surgeons in non-research settings, the use of MIS technologies was associated with reduced intraoperative blood loss but only a half-day reduction in mean length of hospital stay for one-level fusions. Minimally invasive surgery was not associated with any improved perioperative safety measures or 12-month outcomes. Although MIS enabling technologies may increase some in-hospital care efficiencies, MIS clinical outcomes are similar to open surgery for patients undergoing one- and two-level interbody lumbar fusions.

Predictors of extended length of stay, discharge to inpatient rehab, and hospital readmission following elective lumbar spine surgery: introduction of the Carolina-Semmes Grading Scale

OBJECTIVE Extended hospital length of stay (LOS), unplanned hospital readmission, and need for inpatient rehabilitation after elective spine surgery contribute significantly to the variation in surgical health care costs. As novel payment models shift the risk of cost overruns from payers to providers, understanding patient-level risk of LOS, readmission, and inpatient rehabilitation is critical. The authors set out to develop a grading scale that effectively stratifies risk of these costly events after elective surgery for degenerative lumbar pathologies. METHODS The Quality and Outcomes Database (QOD) registry prospectively enrolls patients undergoing surgery for degenerative lumbar spine disease. This registry was queried for patients who had undergone elective 1- to 3-level lumbar surgery for degenerative spine pathology. The association between preoperative patient variables and extended postoperative hospital LOS (LOS ≥ 7 days), discharge status (inpatient facility vs home), and 90-day hospital readmission was assessed using stepwise multivariate logistic regression. The Carolina-Semmes grading scale was constructed using the independent predictors for LOS (0-12 points), discharge to inpatient facility (0-18 points), and 90-day readmission (0-6 points), and its performance was assessed using the QOD data set. The performance of the grading scale was then confirmed separately after using it in 2 separate neurosurgery practice sites (Carolina Neurosurgery & Spine Associates [CNSA] and Semmes Murphey Clinic). RESULTS A total of 6921 patients were analyzed. Overall, 290 (4.2%) patients required extended LOS, 654 (9.4%) required inpatient facility care/rehabilitation on hospital discharge, and 474 (6.8%) were readmitted to the hospital within 90 days postdischarge. Variables that remained as independently associated with these unplanned events in multivariate analysis included age ≥ 70 years, American Society of Anesthesiologists Physical Classification System class > III, Oswestry Disability Index score ≥ 70, diabetes, Medicare/Medicaid, nonindependent ambulation, and fusion. Increasing point totals in the Carolina-Semmes scale effectively stratified the incidence of extended LOS, discharge to facility, and readmission in a stepwise fashion in both the aggregate QOD data set and when subsequently applied to the CNSA/Semmes Murphey practice groups. CONCLUSIONS The authors introduce the Carolina-Semmes grading scale that effectively stratifies the risk of prolonged hospital stay, need for postdischarge inpatient facility care, and 90-day hospital readmission for patients undergoing first-time elective 1- to 3-level degenerative lumbar spine surgery. This grading scale may be helpful in identifying patients who may require additional resource utilization within a global period after surgery.

An analysis from the Quality Outcomes Database, Part 1. Disability, quality of life, and pain outcomes following lumbar spine surgery: predicting likely individual patient outcomes for shared decision-making

OBJECTIVE Quality and outcomes registry platforms lie at the center of many emerging evidence-driven reform models. Specifically, clinical registry data are progressively informing health care decision-making. In this analysis, the authors used data from a national prospective outcomes registry (the Quality Outcomes Database) to develop a predictive model for 12-month postoperative pain, disability, and quality of life (QOL) in patients undergoing elective lumbar spine surgery. METHODS Included in this analysis were 7618 patients who had completed 12 months of follow-up. The authors prospectively assessed baseline and 12-month patient-reported outcomes (PROs) via telephone interviews. The PROs assessed were those ascertained using the Oswestry Disability Index (ODI), EQ-5D, and numeric rating scale (NRS) for back pain (BP) and leg pain (LP). Variables analyzed for the predictive model included age, gender, body mass index, race, education level, history of prior surgery, smoking status, comorbid conditions, American Society of Anesthesiologists (ASA) score, symptom duration, indication for surgery, number of levels surgically treated, history of fusion surgery, surgical approach, receipt of workers' compensation, liability insurance, insurance status, and ambulatory ability. To create a predictive model, each 12-month PRO was treated as an ordinal dependent variable and a separate proportional-odds ordinal logistic regression model was fitted for each PRO. RESULTS There was a significant improvement in all PROs (p < 0.0001) at 12 months following lumbar spine surgery. The most important predictors of overall disability, QOL, and pain outcomes following lumbar spine surgery were employment status, baseline NRS-BP scores, psychological distress, baseline ODI scores, level of education, workers' compensation status, symptom duration, race, baseline NRS-LP scores, ASA score, age, predominant symptom, smoking status, and insurance status. The prediction discrimination of the 4 separate novel predictive models was good, with a c-index of 0.69 for ODI, 0.69 for EQ-5D, 0.67 for NRS-BP, and 0.64 for NRS-LP (i.e., good concordance between predicted outcomes and observed outcomes). CONCLUSIONS This study found that preoperative patient-specific factors derived from a prospective national outcomes registry significantly influence PRO measures of treatment effectiveness at 12 months after lumbar surgery. Novel predictive models constructed with these data hold the potential to improve surgical effectiveness and the overall value of spine surgery by optimizing patient selection and identifying important modifiable factors before a surgery even takes place. Furthermore, these models can advance patient-focused care when used as shared decision-making tools during preoperative patient counseling.

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.

Effect of obesity on cost per quality-adjusted life years gained following anterior cervical discectomy and fusion in elective degenerative pathology

BACKGROUND

Obese patients have greater comorbidities along with higher risk of complications and greater costs after spine surgery, which may result in increased cost and lower quality of life compared with their non-obese counterparts.

PURPOSE

The aim of the present study was to determine cost-utility following anterior cervical discectomy and fusion (ACDF) in obese patients.

STUDY DESIGN

This study analyzed prospectively collected data.

PATIENT SAMPLE

Patients undergoing elective ACDF for degenerative cervical pathology at a single academic institution were included in the study.

OUTCOME MEASURES

Cost and quality-adjusted life years (QALYs) were the outcome measures.

METHODS

One- and two-year medical resource utilization, missed work, and health state values (QALYs) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national payment amounts (direct cost). Patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Total cost (direct+indirect) was used to compute cost per QALY gained. Patients were defined as obese for body mass index (BMI) ≥35 based on the WHO definition of class II obesity. A subgroup analysis was conducted in morbidly obese patients (BMI≥40).

RESULTS

There were significant improvements in pain (neck pain or arm pain), disability (Neck Disability Index), and quality of life (EuroQol-5D and Short Form-12) at 2 years after surgery (p<.001). There was no significant difference in post-discharge health-care resource utilization, direct cost, indirect cost, and total cost between obese and non-obese patients at postoperative 1-year and 2-year follow-up. Mean 2-year direct cost for obese patients was $19,225±$8,065 and $17,635±$6,413 for non-obese patients (p=.14). There was no significant difference in the mean total 2-year cost between obese ($23,144±$9,216) and non-obese ($22,183±$10,564) patients (p=.48). Obese patients had a lower mean cumulative gain in QALYs versus non-obese patients at 2-years (0.34 vs. 0.42, p=.32). Two-year cost-utility in obese ($68,070/QALY) versus non-obese patients ($52,816/QALY) was not significantly different (p=.11). Morbidly obese patients had lower QALYs gained (0.17) and higher cost per QALYs gained ($138,094/QALY) at 2 years.

CONCLUSIONS

Anterior cervical discectomy and fusion provided a significant gain in health state utility in obese patients, with a mean 2-year cost-utility of $68,070 per QALYs gained, which can be considered moderately cost-effective. Morbidly obese patients had lower cost-effectiveness; however, surgery does provide a significant improvement in outcomes. Obesity, and specifically morbid obesity, should to be taken into consideration as physician and hospital reimbursements move toward a bundled model.

Predictors of the efficacy of epidural steroid injections for structural lumbar degenerative pathology

BACKGROUND

Lumbar epidural steroid injection (LESI) is a valuable therapeutic option when administered to the appropriate patient, for the appropriate disease process, at the appropriate time. There is considerable variability in patient-reported outcomes (PROs) after LESI, creating uncertainty as to who will benefit from the therapy and who will not.

PURPOSE

We set out to identify patient attributes, which are important predictors for the achievement of a minimum clinically important difference (MCID) in the Oswestry Disability Index (ODI) after LESI.

STUDY DESIGN

A prospective cohort study was carried out.

PATIENT SAMPLE

A total of 239 consecutive patients undergoing LESI for back-related disability, back pain (BP), and leg pain (LP) associated with degenerative pathology comprised the patient sample.

OUTCOME MEASURES

Baseline and 3-month patient self-reported ODI, numeric rating scale-BP and LP, Euro-Qol-5D, and Short Form (SF)-12 scores were recorded.

METHODS

A total of 239 consecutive patients undergoing LESI for degenerative pathology over a period of 2 years who were enrolled into a prospective web-based registry were included in the study. Using the previously reported anchor-based approach, an MCID threshold of 7.1% was established for ODI after LESI. Each enrolled patient was then dichotomized as a "responder" (achieving MCID) or a "non-responder." Multiple logistic regression analysis was then performed, with the achievement of MCID serving as the outcome of interest. Candidate variables included in the regression analyses were age, gender, employment, insurance type, smoking status, preoperative ambulation, preinjection narcotic use, comorbidities, predominant LP or BP symptoms, symptom duration, diagnosis, number of levels, prior surgery, baseline PROs, type of stenosis (central, lateral recesses, or foraminal), injection route (transforaminal, interlaminar, or caudal), and number of injections. Subsequently, we also randomly selected 80% of the patients to serve as the training data for a multiple logistic regression model. Once this predictive model was built, it was validated using the remaining 20% of patients.

RESULTS

There were 124 (62%) patients who achieved MCID for ODI. The existence of central stenosis (p=.006), TF or IL injection route (p=.02) compared with caudal epidural steroid injection, higher baseline ODI (p=.00001), and a diagnosis of disc herniation (p=.02) increase the odds of achieving MCID for ODI at 3 months. Symptom duration for over a year (p=.006), prior surgery (p=.08), and preinjection anxiety (p=.001) decrease the odds of achieving MCID. The area under the curve (AUC) for our predictive model's receiver-operator characteristic was 0.81 when using the 80% training data set, and the AUC was 0.72 when using the 20% validation data.

CONCLUSION

We have identified patient attributes that are important predictors for the achievement of MCID in ODI 3 months after LESI. The use of these attributes, in the form of a predictive model for LESI efficacy, has the potential to improve decision making around LESI. Spine care providers can use the information to gain insight into the likelihood that a particular patient will experience a meaningful benefit from LESI.

Matched-pair cohort study of 1-year patient-reported outcomes following pelvic fixation

BACKGROUND CONTEXT

Pelvic fixation improves fusion and stability for thoracolumbar constructs that extend across the L5-S1 junction. No patient-reported outcomes have been published to evaluate patients' functional outcomes following these procedures compared with pelvis-sparing procedures.

PURPOSE

The goal of this study is to identify the effect of pelvic fixation on both objective and patient-reported outcomes.

STUDY DESIGN/SETTING

This was a retrospective, matched cohort study.

PATIENT SAMPLE

The sample comprised adult patients undergoing spine surgery at our institution who had complete 1-year postoperative follow-up.

OUTCOME MEASURES

Patient-reported outcome instruments (Oswestry Disability Index [ODI], Short-Form 12-item survey, and EuroQol-5D) and objective measures (length of hospital stay, discharge disposition, postoperative complications, and readmission rates) were considered.

METHODS

We identified patients in our outcomes registry undergoing instrumented spinal fusion involving the pelvis between October 2010 and May 2014 who had 1-year follow-up data. Nearest-neighbor 1:1 matched controls were identified using propensity scoring from the cohort of patients undergoing any spinal procedure which extended caudally to the lumbar spine or sacrum. Objective and patient-reported outcomes were compared between cases and controls.

RESULTS

There were 44 patients who underwent spinal procedures involving the pelvis and had 1-year follow-up data. An equal number of controls were identified and had similar baseline demographic and clinical characteristics. No significant differences were found among operative variables or objective complication rates. Patients undergoing pelvic fixation had moderately greater improvement at 3 months as measured by ODI, but this difference was not present at 1 year. Other patient-reported outcome measures were equivocal between groups.

CONCLUSIONS

This matched cohort study demonstrates that inclusion of the pelvis in spinal hardware constructs is not associated with increased complications and may slightly improve patient disability at 1 year. Given that pelvic fixation may reduce L5-S1 breakdown and improve biomechanics, surgeons should more readily include the pelvis in instrumented fusion procedures.

The present and future of quality measures and public reporting in neurosurgery

Quality measurement and public reporting are intended to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. However, regulatory implementation has created a complex network of reporting requirements for physicians and medical practices. These include Medicare’s Physician Quality Reporting System, Electronic Health Records Meaningful Use, and Value-Based Payment Modifier programs. The common denominator of all these initiatives is that to avoid penalties, physicians must meet “generic” quality standards that, in the case of neurosurgery and many other specialties, are not pertinent to everyday clinical practice and hold specialists accountable for care decisions outside of their direct control.

The Centers for Medicare and Medicaid Services has recently authorized alternative quality reporting mechanisms for the Physician Quality Reporting System, which allow registries to become subspecialty-reporting mechanisms under the Qualified Clinical Data Registry (QCDR) program. These programs further give subspecialties latitude to develop measures of health care quality that are relevant to the care provided. As such, these programs amplify the power of clinical registries by allowing more accurate assessment of practice patterns, patient experiences, and overall health care value. Neurosurgery has been at the forefront of these developments, leveraging the experience of the National Neurosurgery Quality and Outcomes Database to create one of the first specialty-specific QCDRs.

Recent legislative reform has continued to change this landscape and has fueled optimism that registries (including QCDRs) and other specialty-driven quality measures will be a prominent feature of federal and private sector quality improvement initiatives. These physician- and patient-driven methods will allow neurosurgery to underscore the value of interventions, contribute to the development of sustainable health care solutions, and actively participate in meaningful quality initiatives for the benefit of the patients served.

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.

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.

The National Neurosurgery Quality and Outcomes Database Qualified Clinical Data Registry: 2015 measure specifications and rationale

Meaningful quality measurement and public reporting have the potential to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. Recent developments in national quality reporting programs, such as the Centers for Medicare & Medicaid Services Qualified Clinical Data Registry (QCDR) reporting option, have enhanced the ability of specialty groups to develop relevant quality measures of the care they deliver. QCDRs will complete the collection and submission of Physician Quality Reporting System (PQRS) quality measures data on behalf of individual eligible professionals. The National Neurosurgery Quality and Outcomes Database (N2QOD) offers 21 non-PQRS measures, initially focused on spine procedures, which are the first specialty-specific measures for neurosurgery. Securing QCDR status for N2QOD is a tremendously important accomplishment for our specialty. This program will ensure that data collected through our registries and used for PQRS is meaningful for neurosurgeons, related spine care practitioners, their patients, and other stakeholders. The 2015 N2QOD QCDR is further evidence of neurosurgery’s commitment to substantively advancing the health care quality paradigm. The following manuscript outlines the measures now approved for use in the 2015 N2QOD QCDR. Measure specifications (measure type and descriptions, related measures, if any, as well as relevant National Quality Strategy domain[s]) along with rationale are provided for each measure.

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.

Cost-effectiveness of three treatment strategies for lumbar spinal stenosis: Conservative care, laminectomy, and the Superion interspinous spacer

BACKGROUND

Lumbar spinal stenosis is a painful and debilitating condition resulting in healthcare costs totaling tens of billions of dollars annually. Initial treatment consists of conservative care modalities such as physical therapy, NSAIDs, opioids, and steroid injections. Patients refractory to these therapies can undergo decompressive surgery, which has good long-term efficacy but is more traumatic and can be associated with high post-operative adverse event (AE) rates. Interspinous spacers have been developed to offer a less-invasive alternative. The objective of this study was to compare the costs and quality adjusted life years (QALYs) gained of conservative care (CC) and decompressive surgery (DS) to a new minimally-invasive interspinous spacer.

METHODS

A Markov model was developed evaluating 3 strategies of care for lumbar spinal stenosis. If initial therapies failed, the model moved patients to more invasive therapies. Data from the Superion FDA clinical trial, a prospective spinal registry, and the literature were used to populate the model. Direct medical care costs were modeled from 2014 Medicare reimbursements for healthcare services. QALYs came from the SF-12 PCS and MCS components. The analysis used a 2-year time horizon with a 3% discount rate.

RESULTS

CC had the lowest cost at $10,540, while Spacers and DS were nearly identical at about $13,950. CC also had the lowest QALY increase (0.06), while Spacers and DS were again nearly identical (.28). The incremental cost-effectiveness ratios (ICER) for Spacers compared to CC was $16,300 and for DS was $15,200.

CONCLUSIONS

Both the Spacer and DS strategies are far below the commonly cited $50,000/QALY threshold and produced several times the QALY increase versus CC, suggesting that surgical care provides superior value (cost / effectiveness) versus sustained conservative care in the treatment of lumbar spinal stenosis.

Quality of Life and General Health After Elective Surgery for Cervical Spine Pathologies

BACKGROUND:

As part of the Affordable Care Act, health utility metrics are being investigated to define a cost-effective, value-based health care model. EuroQOL-5D (EQ-5D) and Short Form-6D (SF-6D) are commonly used quality-of-life instruments. Domains in the EQ-5D questionnaire are thought to be less responsive in measuring quality of life after cervical surgery.

OBJECTIVE:

To evaluate the validity and responsiveness of SF-6D and EQ-5D in determining health and quality of life after elective cervical spine surgery.

METHODS:

A total of 420 patients undergoing elective cervical spine surgery over a period of 2 years were enrolled in a prospective longitudinal registry. Patient-reported outcomes Neck Disability Index (NDI), EQ-5D, and SF-12 were recorded. Based on previously published equations, SF-6D was calculated using NDI and SF-12 scores. Patients were asked whether “surgery met their expectations” (meaningful improvement). The validity and relative responsiveness of SF-6D (NDI), SF-6D (SF-12), and EQ-5D to discriminate between meaningful and nonmeaningful improvement were calculated.

RESULTS:

Sixty-six percent of patients (277) reported a level of improvement after surgery that met their expectations (meaningful improvement). SF-6D (NDI) (area under the curve [AUC] = 0.69) was a more valid discriminator of meaningful improvement compared with the SF-6D (SF-12) (AUC = 0.65) and EQ-5D (AUC = 0.62). SF-6D (NDI) was also a more responsive measure compared with SF-6D (SF-12) and EQ-5D (standardized response mean difference: 0.66, 0.48, and 0.44, respectively).

CONCLUSION:

SF-6D is a more valid and responsive measure of general health and quality of life compared with EQ-5D. SF-6D derived from disease-specific disability scores was more valid and responsive than that derived from the generic preference-based SF-12. Cost-effective studies should use SF-6D as a measure of QALY after cervical spine surgery.

Accurately measuring the quality and effectiveness of cervical spine surgery in registry efforts: determining the most valid and responsive instruments

BACKGROUND CONTEXT

There is a growing demand to measure the real-world effectiveness and value of care across all specialties and disease states. Prospective registries have emerged as a feasible way to capture real-world care across large patient populations. However, the proven validity of more robust and cumbersome patient-reported outcome instruments (PROi) must be balanced with what is feasible to apply in large-scale registry efforts. Hence, commercial registry efforts that measure quality and effectiveness of care in an attempt to guide quality improvement, pay for performance, or value-based purchasing should incorporate measures that most accurately represent patient-centered improvement.

PURPOSE

We set out to establish the relative validity and responsiveness of common PROi in accurately determining effectiveness of cervical surgery for neck and arm pain in registry efforts.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

Eighty-eight patients undergoing primary anterior cervical discectomy and fusion (ACDF) for neck and arm pain.

OUTCOME MEASURES

Patient-reported outcome measures for pain (numeric rating scale for neck pain [NRS-NP] and arm pain [NRS-AP]), disability (neck disability index [NDI]), general health (short-form 12-item survey physical component summary [SF-12 PCS] and mental component summary [SF-12 MCS]), and quality of life (Euro-Qol-5D [EQ-5D]) were assessed.

METHODS

Eighty-eight patients undergoing primary ACDF for neck and arm pain were entered into a Web-based prospective registry. Baseline and 12-month patient-reported outcomes (NRS-NP, NRS-AP, NDI, SF-12 PCS, SF-12 MCS, and EQ-5D) were assessed. Patients were also asked whether they experienced a level of improvement after ACDF that met their expectation (meaningful improvement). To assess the validity of NRS-NP, NRS-AP, and NDI (measures of pain and disability) to discriminate between meaningful and nonmeaningful improvement and the validity of SF-12 PCS, SF-12 MCS, and EQ-5D (measures of general health and quality of life) to discriminate between meaningful and nonmeaningful improvement, receiver-operating characteristic curves were generated for each outcome instrument. The greater the area under the curve (AUC), the more valid the discriminator. The difference between standardized response means (SRMs) in patients reporting meaningful improvement versus not was calculated to determine the relative responsiveness of each outcome instrument to changes in pain and QOL after surgery.

RESULTS

For pain and disability, both NDI (AUC=0.75) and NRS-AP (AUC=0.74) were valid discriminators of meaningful improvement. Numeric rating scale for neck pain (AUC=0.69) was a poor discriminator. Neck disability index was also most responsive to postoperative improvement (SRM difference 0.78), followed by NRS-AP (SRM difference 0.59) and NRS-NP (SRM difference 0.46). For general health and quality of life, SF-12 PCS (AUC=0.79) was the only valid discriminator of meaningful improvement. Euro-Qol-5D (AUC=0.68) and SF-12 MCS (AUC=0.44) were poor discriminators. Short-form 12 physical component summary (SRM difference 1.08) was also most responsive compared with EQ-5D (SRM difference 0.89) and SF-12 MCS (SRM difference 0.01).

CONCLUSIONS

For pain and disability, NDI is the most valid and responsive measure of improvement after surgery for neck and arm pain. Numeric rating scale for neck pain and NRS-AP are poor substitutes for NDI when measuring effectiveness of care in registry efforts. For health-related quality of life, only SF-12 PCS could accurately discriminate meaningful improvement after cervical surgery and was found to be most valid and responsive. Large-scale registry efforts aimed at measuring effectiveness of cervical spine surgery should use NDI and SF-12 to accurately assess improvements in pain, disability, and quality of life.

Incidence of Low Back Pain After Lumbar Discectomy for Herniated Disc and Its Effect on Patient-reported Outcomes

BACKGROUND

Long-term postdiscectomy degenerative disc disease and low back pain is a well-recognized disorder; however, its patient-centered characterization and quantification are lacking.

QUESTIONS/PURPOSES

We performed a systematic literature review and prospective longitudinal study to determine the frequency of recurrent back pain after discectomy and quantify its effect on patient-reported outcomes (PROs).

METHODS

A MEDLINE search was performed to identify studies reporting on the frequency of recurrent back pain, same-level recurrent disc herniation, and reoperation after primary lumbar discectomy. After excluding studies that did not report the percentage of patients with persistent back or leg pain more than 6 months after discectomy or did not report the rate of same level recurrent herniation, 90 studies, which in aggregate had evaluated 21,180 patients, were included in the systematic review portion of this study. For the longitudinal study, all patients undergoing primary lumbar discectomy between October 2010 and March 2013 were enrolled into our prospective spine registry. One hundred fifteen patients were more than 12 months out from surgery, 103 (90%) of whom were available for 1-year outcomes assessment. PROs were prospectively assessed at baseline, 3 months, 1 year, and 2 years. The threshold of deterioration used to classify recurrent back pain was the minimum clinically important difference in back pain (Numeric Rating Scale Back Pain [NRS-BP]) or Disability (Oswestry Disability Index [ODI]), which were 2.5 of 10 points and 20 of 100 points, respectively.

RESULTS SYSTEMATIC REVIEW

The proportion of patients reporting short-term (6-24 months) and long-term (> 24 months) recurrent back pain ranged from 3% to 34% and 5% to 36%, respectively. The 2-year incidence of recurrent disc herniation ranged from 0% to 23% and the frequency of reoperation ranged from 0% to 13%.

PROSPECTIVE STUDY

At 1-year and 2-year followup, 22% and 26% patients reported worsening of low back pain (NRS: 5.3 ± 2.5 versus 2.7 ± 2.8, p < 0.001) or disability (ODI%: 32 ± 18 versus 21 ± 18, p < 0.001) compared with 3 months.

CONCLUSIONS

In a systematic literature review and prospective outcomes study, the frequency of same-level disc herniation requiring reoperation was 6%. Two-year recurrent low back pain may occur in 15% to 25% of patients depending on the level of recurrent pain considered clinically important, and this leads to worse PROs at 1 and 2 years postoperatively.

Determination of the minimum improvement in pain, disability, and health state associated with cost-effectiveness: introduction of the concept of minimum cost-effective difference

BACKGROUND

Minimum clinical important difference (MCID) has been adopted as the smallest improvement in patient-reported outcome needed to achieve a level of improvement thought to be meaningful to patients.

OBJECTIVE

To use a common MCID calculation method with a cost-utility threshold anchor to introduce the concept of minimum cost-effective difference (MCED).

METHODS

Forty-five patients undergoing transforaminal lumbar interbody fusion for degenerative spondylolisthesis were included. Outcome questionnaires were administered before and 2 years after surgery. Total cost per quality-adjusted life-year (QALY) gained was calculated for each patient. MCED was determined from receiver-operating characteristic curve analysis with a cost-effective anchor of < $50,000/QALY and < $75,000/QALY. MCID was determined with the health transition item as the anchor.

RESULTS

Significant improvement was observed 2 years after transforaminal lumbar interbody fusion for all outcome measures. Mean total cost per QALY gained at 2 years was $42,854. MCED was greater than MCID for each outcome measure, meaning that a greater improvement was required to represent cost-effectiveness than a clinically meaningful improvement to patients. The area under the receiver-operating characteristic curve was consistently ≥ 0.70 with both cost-effective anchors, suggesting that outcome change scores were accurate predictors of cost-effectiveness. Mean cost per QALY gained was significantly lower for patients achieving compared with those not achieving an MCED in visual analog scale for leg pain ($43,560 vs $112,087), visual analog scale for back pain ($41,280 vs $129440), Oswestry Disability Index ($30,954 vs $121,750), and EuroQol 5D ($35800 vs $189412).

CONCLUSION

MCED serves as the smallest improvement in an outcome instrument that is associated with a cost-effective response to surgery. With the use of cost-effective anchor of < $50,000/QALY, MCED after transforaminal lumbar interbody fusion was 4 points for visual analog scale for low back pain, 3 points for visual analog scale for leg pain, 22 points for Oswestry Disability Index, and 0.31 QALYs for EuroQol 5D.