Inadequacy of 3-month Oswestry Disability Index outcome for assessing individual longer-term patient experience after lumbar spine surgery

2nd and 3rd generation full endoscopic lumbar spine surgery: clinical safety and learning curve

AIM

2nd and 3rd generation endoscopic spine surgery techniques offer visualisation of familiar inter-laminar anatomy to spinal surgeons. We have prospectively evaluated the clinical outcome, complications and learning curve associated with these techniques in patients with lumbar spine radiculopathy.

METHODS

This is a prospective study of 50 consecutive patients with radicular pain from disc herniation and/or lateral recess stenosis. In 6 patients, endoscopy couldn't be done. Operating times, PROM's (VAS, ODI and EQ-5D scores) and complication rates of 44 patients were evaluated after mean FU of 52 months (range 39-65). MRI was used to divide these into protrusions (n = 19), extrusions (n = 17) and lateral recess stenosis (n = 8). Evidence about the learning curve was gathered by curvilinear regression analyses.

RESULTS

Using a composite clinical success criterion, 95% patients had a successful outcome, with no major complications. ODI, VAS and EQ-5D scores had a statistically significant improvement and achieved MCID. Revision discectomy rate was only 4.5% (n = 2). MRI based grouping, case sequence and degree of difficulty influenced the duration of surgery and a learning curve was found for protrusions and lateral recess decompressions, but not for extrusions. A learning curve effect was also observed with respect to the ODI.

CONCLUSIONS

Although anatomy visualised in 2nd and 3rd generation endoscopy is familiar to spinal surgeons, our learning curve experience suggests a careful and MRI pathology based take up of this technique in clinical practice, despite its clinical safety in our series.

LEVEL OF EVIDENCE

Level 3, prospective cohort study.

Clinical Outcomes with and without Adherence to Evidence-Based Medicine Guidelines for Lumbar Degenerative Spondylolisthesis Fusion Patients

INTRODUCTION

Degenerative lumbar spondylolisthesis (DS) patients are treated with instrumented fusion, following EBM guidelines, and typically have excellent clinical outcomes. However, not all lumbar fusion procedures adhere to EBM guidelines, typically due to a lack of prospective data.

OBJECTIVE

This retrospective study compared outcomes of DS lumbar fusion patients treated according to EBM guidelines (EBM concordant) to lumbar fused patients with procedures that did not have clear EBM literature that supported this treatment, the goal being to examine the value of present EBM to guide clinical care.

METHODS

A total of 125 DS patients were considered EBM concordant, while 21 patients were EBM discordant. Pre- and postsurgical ODI scores were collected. Clinical outcomes were stratified into substantial clinical benefit (SCB ΔODI >10 points), minimal clinical importance benefit (MCID ΔODI ≥ 5 points), no MCID (ΔODI < 5 points), and a group that showed no change or worsening ODI. Fisher's exact and χ2 tests for categorical variables, Student's t-test for continuous variables, and descriptive statistics were used. Statistical tests were computed at the 95% level of confidence.

RESULTS

Analysis of 125 degenerative spondylolisthesis patients was performed comparing preoperative and postoperative (6 months) ODI scores. ODI improved by 8 points in the EBM concordant group vs. 2.1 points in the EBM discordant group (p = 0.002). Compliance with EBM guidelines was associated with an odds ratio (OR) of 2.93 for achieving MCID ([CI]: 1.12-7.58, p = 0.027).

CONCLUSIONS

Patients whose lumbar fusions met EBM criteria had better self-reported outcomes at six months than those who did not meet the requirements. A greater knowledge set is needed to help further support EBM-guided patient care.

Do Patient Outcomes Predict Loss to Long-Term Follow-Up After Spine Surgery?

OBJECTIVE

To determine if spine surgery patients with greater improvement in patient-reported outcomes measures (PROMs) at early postoperative follow-up are more likely to be lost to follow-up at the 1-year and 2-year postoperative visits.

METHODS

All patients older than 18 years who underwent primary or revision decompression or fusion surgery for degenerative spinal conditions at an academic institution were retrospectively identified. Univariate analysis compared patient demographics, surgical factors, and changes in short-term and long-term postoperative PROMs (Neck Disability Index, Oswestry Disability Index, visual analog scale [VAS] neck, VAS arm, VAS back, VAS leg, and Short-Form 12 Physical and Mental Component Scores) across groups with and without 1 year and 2 years follow-up. Logistic regression isolated predictors of loss to follow-up.

RESULTS

A total of 1412 patients were included. Younger patient age, primary surgery, and single surgical approach independently predicted loss at 1 year follow-up. Female sex predicted loss at 2 years follow-up, whereas multilevel fusion surgery predicted attendance at 2 years clinical follow-up. In patients lost at 1 year follow-up compared with those who attended, preoperative to 3-month Mental Component Score and VAS neck pain improvement was significantly greater. When comparing patients based on 2 years follow-up status, VAS back pain improvement at 1 year postoperatively was significantly greater in patients lost to 2 years follow-up. All other changes in PROMs did not differ significantly by 1 or 2 years follow-up attendance.

CONCLUSIONS

Overall patient outcomes were not found to affect loss to long-term follow-up after spine surgery. The general lack of association between postoperative follow-up status and clinical outcome may limit bias introduced in retrospective PROM studies.

Quality Outcomes Database Spine Care Project 2012-2020: milestones achieved in a collaborative North American outcomes registry to advance value-based spine care and evolution to the American Spine Registry

The Quality Outcomes Database (QOD), formerly known as the National Neurosurgery Quality Outcomes Database (N2QOD), was established by the NeuroPoint Alliance (NPA) in collaboration with relevant national stakeholders and experts. The overarching goal of this project was to develop a centralized, nationally coordinated effort to allow individual surgeons and practice groups to collect, measure, and analyze practice patterns and neurosurgical outcomes. Specific objectives of this registry program were as follows: "1) to establish risk-adjusted national benchmarks for both the safety and effectiveness of neurosurgical procedures, 2) to allow practice groups and hospitals to analyze their individual morbidity and clinical outcomes in real time, 3) to generate both quality and efficiency data to support claims made to public and private payers and objectively demonstrate the value of care to other stakeholders, 4) to demonstrate the comparative effectiveness of neurosurgical and spine procedures, 5) to develop sophisticated 'risk models' to determine which subpopulations of patients are most likely to benefit from specific surgical interventions, and 6) to facilitate essential multicenter trials and other cooperative clinical studies." The NPA has launched several neurosurgical specialty modules in the QOD program in the 7 years since its inception including lumbar spine, cervical spine, and spinal deformity and cerebrovascular and intracranial tumor. The QOD Spine modules, which are the primary subject of this paper, have evolved into the largest North American spine registries yet created and have resulted in unprecedented cooperative activities within our specialty and among affiliated spine care practitioners. Herein, the authors discuss the experience of QOD Spine programs to date, with a brief description of their inception, some of the key achievements and milestones, as well as the recent transition of the spine modules to the American Spine Registry (ASR), a collaboration between the American Association of Neurological Surgeons and the American Academy of Orthopaedic Surgeons (AAOS).

Endoscopic Transforaminal Lumbar Interbody Fusion With a Single Oblique PEEK Cage and Posterior Supplemental Fixation

BACKGROUND

To demonstrate the feasibility of an endoscopically assisted minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF) and to study clinical outcomes with the use of a static oblique bullet-shaped cannulated poly-ether-ether-ketone (PEEK) lumbar interbody fusion cage in conjunction with platelet enriched plasma infused allograft cancellous chips and posterior supplemental fixation.

METHODS

In this retrospective study of 43 patients who underwent endoscopically assisted MIS-TLIF for spondylolisthesis (53.5%) and stenosis (46.3%), the Oswestry Disability Index, the visual analog scale (VAS) for back and leg pain, and the modified Macnab criteria were used as primary clinical outcome measures. Clinical outcomes were cross-tabulated against fusion grade using the Bridwell classification of interbody fusion.

RESULTS

The majority of patients (90.7%) had excellent (8/43; 18.6%) and good (31/43; 72.1%) Macnab outcomes. There were significant VAS back score reductions from an average preoperative values of 8.9070 to a postoperative VAS score of 3.8605, and a score of 2.7674 at final follow-up (P < .0001). The reductions in the VAS leg scores were also significant from preoperative score of 5.58 to a postoperative value of 2.16, and a final follow-up score of 1.67 (P < .0001); the Oswestry Disability Index score went from a preoperative value of 54.4 to 23.3 postoperatively and 18.5 at the final follow-up (P < .0001). The vast majority of patients (92.9%) with Bridwell grade I fusion had excellent and good Macnab outcomes (P = .027).

CONCLUSIONS

The authors recommend the use of an endoscope as an adjunct to MIS-TLIF, a minimally invasive spinal surgery technique in which many surgeons may be well versed and have a great deal of experience. Clinical outcomes with the endoscopic interbody fusion procedure with a static PEEK cage in conjunction with platelet-enriched bone allograft were favorable.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Feasibility study.

Lumbar Endoscopic Bony and Soft Tissue Decompression With the Hybridized Inside-Out Approach: A Review And Technical Note

This study aimed to showcase the authors' preferred technique of a hybrid of modern "inside-out" and "outside-in" endoscopic decompression. A case series of 411 patients consisting of 192 females (46.7%) and 219 males (53.3%) with an average age of 54.84 ± 16.32 years and an average of 43.2 ± 26.53 months are presented. Patients underwent surgery for low-grade spondylolisthesis (13 of 411, 3.2%), herniated disc (135 of 411, 32.8%), foraminal spinal stenosis (101 of 411, 24.6%), or a combination of the latter 2 conditions (162 of 411, 39.4%). The preoperative Oswestry Disability Index (ODI) and visual analogue scale (VAS) for leg pain were 49.8 ± 17.65 and 7.9 ± 1.55, respectively. Postoperative ODI and VAS leg were 12.2 ± 9.34 and 2.41 ± 5 1.55 at final follow-up (p < 0.0001). MacNab outcomes were excellent in 134 (32.6%), good in 228 (55.5%), fair in 40 (9.7%), and poor in 9 patients (2.2%), respectively. There was end-stage degenerative vacuum disc disease in 304 of the 411 patients (74%) of which had 37.5% had excellent and 50% good MacNab outcomes. Patients without vacuum discs had excellent and good 18.7% and 71.0% of the time. Direct visualization of pain generators in the epidural- and intradiscal space is the authors' preferred transforaminal decompression technique and is supported by their reliable clinical outcomes.

Minimal Clinically Important Difference in Patient-Reported Outcome Measures with the Transforaminal Endoscopic Decompression for Lateral Recess and Foraminal Stenosis

Background

Patient-reported outcome measures (PROMs) have become widely used to better measure patients' judgment of treatment benefits from surgical spine care. The concept of determining the minimal clinically important differences (MCIDs) of PROMs is aimed at assessing the benefits of lumbar spine care that are meaningful to the patient. The goal of this study was to validate the utility of MCIDs of the visual analog score (VAS) and Oswestry Disability Index (ODI) in patients with sciatica-type low back and leg pain due to lateral recess and foraminal stenosis who were treated with directly visualized transforaminal outpatient endoscopic decompression.

Methods

The retrospective study population consisted of 406 patients on whom PROMs were obtained preoperatively, and again postoperatively at final follow-up. Employing an anchor-based approach with a patient satisfaction index based on the modified Macnab criteria, a receiver operating characteristics (ROC) and area under the curve (AUC) analysis was performed using IBM SPSS 25.0 to define the optimal MCID in VAS and ODI with the transforaminal endoscopy using the top-left-corner criteria and the Youden index. Improvements in walking endurance were recorded as an additional parameter of patient functioning and correlated with PROMs to test for statistical significance.

Results

The patients' average age was 41.08 years, ranging from 30 to 84 years. The mean follow-up was 33.59 months, ranging from 24 to 85 months, with a standard deviation of 12.79. The MCIDs for VAS and ODI were 2.5 to 3.5 and 15 to 16.5, respectively. Patients were dichotomized as improved (377/406; 92.9%) if they reported excellent (224/406; 55.2%), good (112/406; 27.6%), and fair (41/406; 10.1%) Macnab outcomes. Patients were dichotomized as failed if they reported poor (29/406; 7.1%) Macnab outcomes. Preoperatively, only 32.5% (132/406) of patients had unlimited walking endurance compared to 77.6% (315/406) of patients postoperatively. The ROC and AUC analysis showed better accuracy with the single-integer VAS score (0.926) than with the 10-item ODI score (0.751).

Conclusions

Transforaminal outpatient endoscopic decompression for symptomatic foraminal and lateral recess stenosis is an effective surgical treatment to alleviate sciatica-type and back symptoms in 92.9% of patients. Of the PROMs analyzed, the VAS provided a more meaningful and accurate reflection of patients' interpretation of outcome with the transforaminal endoscopic spinal decompression procedure than ODI. Understanding which patient expectations drive these MCIDs may aid in replacing open surgeries for sciatica-type low back and leg pain currently preferred by traditional spine surgeons with a personalized early-staged transforaminal endoscopic hybrid decompressive/ablative procedures favored by the authors. These may prove more cost effective by focusing on significant pain generators validated with a diagnostic interventional workup instead of employing image-based indication criteria for surgery.

Adding 3-month patient data improves prognostic models of 12-month disability, pain, and satisfaction after specific lumbar spine surgical procedures: development and validation of a prediction model

BACKGROUND CONTEXT

Prognostic models including early postoperative variables may provide optimal estimates of long-term outcomes and help direct postoperative care.

PURPOSE

To develop and validate prognostic models for 12-month disability, back pain, leg pain, and satisfaction among patients undergoing microdiscectomy, laminectomy, and laminectomy with fusion for degenerative lumbar conditions.

STUDY DESIGN/SETTING

Retrospective cohort study using the Quality Outcomes Database.

PATIENT SAMPLE

Patients receiving elective lumbar spine surgery due to degenerative spine conditions.

OUTCOME MEASURES

Oswestry Disability Index, pain numerical rating scale, and NASS Patient Satisfaction Index.

METHODS

Prognostic models were developed using proportional odds ordinal logistic regression using patient characteristics and baseline and 3-month patient-reported outcome scores. Models were fit for each outcome stratified by type of surgical procedure. Adjusted odds ratio and 95% confidence intervals were reported for all predictors by procedure. Models were internally validated using bootstrap resampling. Discrimination was reported as the c-index and calibration was presented using the calibration slope. We compared the performance of models with and without 3-month patient-reported variables. This research was supported by the Foundation for Physical Therapy's Center of Excellence in Physical Therapy Health Services, and Health Policy Research and Training grant.

RESULTS

The sample consisted of 5,840 patients receiving a microdiscectomy (n=2,085), laminectomy (n=1,837), or laminectomy with fusion (n=1,918). The 3-month Oswestry score was the strongest and most consistent predictor associated with 12-month outcomes. All prognostic models performed well with overfitting-corrected c-index values ranging from 0.718 to 0.795 and all optimism corrected calibration slopes over 0.92. The increase in c-index values ranged from 0.09 to 0.21 when adding 3-month patient-reported outcome scores.

CONCLUSIONS

Models had good discrimination and were well calibrated for estimating 12-month disability, back pain, leg pain, and satisfaction. Patient-reported outcomes at 3 months after surgery, especially 3-month Oswestry scores, improved the 12-month performance of all prognostic models beyond using only baseline variables.

Lumbar disc herniation surgery in adolescents and young adults

Aims

The purpose of this study was to investigate the risk of additional surgery in the lumbar spine and to describe long-term changes in patient-reported outcomes after surgery for lumbar disc herniation in adolescents and young adults.

Patients and Methods

We conducted a retrospective study design on prospectively collected data from a national quality register. The 4537 patients were divided into two groups: adolescents (≤ 18 years old, n = 151) and young adults (19 to 39 years old, n = 4386). The risk of additional lumbar spine surgery was surveyed for a mean of 11.4 years (6.0 to 19.3) in all 4537 patients. Long-term patient-reported outcomes were available at a mean of 7.2 years (5.0 to 10.0) in up to 2716 patients and included satisfaction, global assessment for leg and back pain, Oswestry Disability Index, visual analogue scale for leg and back pain, EuroQol five-dimension questionnaire (EQ-5D), and 36-Item Short-Form Health Survey (SF-36) Mental Component Summary and Physical Component Summary scores. Statistical analyses were performed with Cox proportional hazard regression, chi-squared test, McNemar’s test, Welch–Satterthwaite t-test, and Wilcoxon’s signed-rank test.

Results

Any type of additional lumbar spine surgery was seen in 796 patients (18%). Surgery for lumbar disc herniation accounted for more than half of the additional surgeries. The risk of any additional surgery was 0.9 (95% confidence interval (CI) 0.6 to 1.4) and the risk of additional lumbar disc herniation surgery was 1.0 (0.6 to 1.7) in adolescents compared with the young adult group. Both age groups improved their patient-reported outcome data after surgery (all p < 0.001). Changes between short- (mean 1.9 years (1.0 to 2.0)) and long-term follow-up (mean 7.2 years (5.0 to 10.0)) were small.

Conclusion

The risk of any additional lumbar spine surgery and additional lumbar disc herniation surgery was similar in adolescents and young adults. All patient-reported outcomes improved from preoperative to the short-term follow-up, while no likely clinically important differences between the short- and long-term follow-up were seen within both groups. Cite this article: Bone Joint J 2019;101-B:1534–1541

Predictors of loss of follow-up in a prospective registry: which patients drop out 12 months after lumbar spine surgery?

BACKGROUND CONTEXT

Long-term patient-reported outcomes (PROMs) are essential in clinical practice and research. Prospective trials and registries often struggle with high rates of loss of follow-up (LOFU), which may bias their findings. Little is known on risk factors for PROM nonresponse, especially for digitally mailed questionnaires.

PURPOSE

To elucidate which patients are at high risk for LOFU by identifying associated predictors.

STUDY DESIGN

Analysis of a prospective registry.

PATIENT SAMPLE

Patients that underwent surgery for degenerative lumbar disease were included.

OUTCOME MEASURES

Rate of PROM follow-up response at 12 months postoperatively.

METHODS

Preoperatively and at 12 months postoperatively, patients were asked to complete a range of PROM questionnaires using a web-based tool. All patients who successfully completed their baseline questionnaire were included. Patients were not actively reminded upon nonresponse. Univariate and independent predictors of LOFU at 12 months were identified.

RESULTS

We included 1,456 patients, of which 861 (59%) were lost to follow-up at 12 months. Univariately, lower age, American Society of Anesthesiologists (ASA) class 1, smoking, lack of prior surgery, higher pain scores and functional disability, and lower quality-of-life were associated with LOFU (all p<.05). Only lower age (OR: 0.98, p=.001), smoking (OR: 1.46, p=.019), lack of prior surgery (OR: 0.59, p=.019), and spondylolisthesis (OR: 0.47, p=.024) independently predicted LOFU.

CONCLUSIONS

In a prospective registry of lumbar spine surgery patients based on web-based outcome capturing, younger age, active smoking status, lack of prior surgery, and nonspondylolisthesis surgery were independent predictors of loss of follow-up. In the future, it may become possible to preoperatively identify patients at high-risk for study dropout. As the implementation of prospective registries and the use of automated follow-up methods are on the rise, it is crucial to ensure efficiency and reduce bias of the methods on which all clinical research is based on.

Future Studies and Directions for the Optimization of Outcomes for Lumbar Spondylolisthesis

Randomized prospective studies show clear benefits for operative versus nonoperative management of symptomatic lumbar spondylolisthesis, but there is no universally accepted surgical treatment. This article presents options for surgical management of lumbar spondylolisthesis, reviews the clinical trials delineating the role and type of surgical intervention, and explores the directions of future investigations. The next decade will add further clarity to the surgical management of spondylolisthesis, not by randomized prospective trials, but by surgical registries. The power of "big data" offered by registries will likely become the vehicle best suited to amass data on current and novel therapies.

Patient-reported outcomes unbiased by length of follow-up after lumbar degenerative spine surgery: Do we need 2 years of follow-up?

BACKGROUND

In modern clinical research, the accepted minimum follow-up for patient-reported outcome measures (PROMs) after lumbar spine surgery is 24 months, particularly after fusion. Recently, this minimum requirement has been called into question.

PURPOSE

We aim to quantify the concordance of 1- and 2-year PROMs to evaluate the importance of long-term follow-up after elective lumbar spine surgery.

STUDY DESIGN

Retrospective analysis of data from a prospective registry.

PATIENT SAMPLE

We identified all patients in our prospective institutional registry who underwent degenerative lumbar spine surgery with complete baseline, 12-month, and 24-month follow-up for ODI and numeric rating scales for back and leg pain (NRS-BP and NRS-LP).

OUTCOME MEASURES

Oswestry Disability Index (ODI) and NRS-BP and NRS-LP at 1 year and at 2 years.

METHODS

We evaluated concordance of 1- and 2-year change scores by means of Pearson's product-moment correlation and performed logistic regression to assess if achieving the minimum clinically important difference (MCID) at 12 months predicted 24-month MCID. Odds ratios (OR) and their 95% confidence intervals (CI), as well as model areas-under-the-curve were obtained.

RESULTS

A total of 210 patients were included. We observed excellent correlation among 12- and 24-month ODI (r = 0.88), NRS-LP (r = 0.76) and NRS-BP (r = 0.72, all p <.001). Equal results were obtained when stratifying for discectomy, decompression, or fusion. Patients achieving 12-month MCID were likely to achieve 24-month MCID for ODI (OR: 3.3, 95% CI: 2.4-4.1), NRS-LP (OR: 2.99, 95% CI: 2.2-4.2) and NRS-BP (OR: 3.4, 95% CI: 2.7-4.2, all p <.001) with excellent areas-under-the-curve values of 0.81, 0.77, and 0.84, respectively. Concordance rates between MCID at both follow-ups were 87.2%, 83.8%, and 84.2%. A post-hoc power analysis demonstrated sufficient statistical power.

CONCLUSIONS

Irrespective of the surgical procedure, 12-month PROMs for functional disability and pain severity accurately reflect those at 24 months. In support of previous literature, our results suggest that 12 months of follow-up may be sufficient for evaluating spinal patient care in clinical practice as well as in research.

Clinical outcomes research in spine surgery: what are appropriate follow-up times?

In BriefThe time course required for the patient-reported outcomes of pain, physical function, and mental health to reach a recovery plateau after elective lumbar spine surgery was assessed utilizing a prospectively maintained multicenter registry. The work is important as it demonstrates that specific health dimensions follow different recovery plateaus and it provides evidence that a 2-year postoperative follow-up is not required to accurately assess the treatment effect of established surgeries for lumbar spinal pathologies.

Thoracolumbar Fusion in Extreme Obesity: Complications and Patient-Reported Outcomes

Background

Extreme obesity (class III) is defined by the Centers for Disease Control as a body mass index (BMI) value ≥40. Recent studies suggest that obese patients have poor outcomes after thoracolumbar spinal fusions. The objective of this study was to analyze 30-day adverse events and patient-reported outcomes (PROs) for this population.

Patients and Methods

A retrospective chart review of spinal fusion surgeries performed at a single institution from 2006 to 2016 was executed. All patients had a preoperative BMI ≥40. Patient characteristics, including age, sex, BMI, American Society of Anesthesiologists (ASA) score, Charlson Comorbidity Index (CCI), and others, were collected. Thirty-day adverse events (complications, readmissions, reoperations, and mortality) and PROs (Oswestry Disability Index [ODI] and visual analog scale [VAS]) were recorded.

Results

Fifty-six patients were identified, including 30 men (54%). Mean age was 55.7 years (range, 31-74 years). Mean BMI was 44.2 (range, 40.0-54.7). Mean ASA was 2.7 (range, 2-3), and mean CCI was 1.1 (range, 0-6). Mean number of fused levels was 2.3 (range, 1-14). Mean length of stay was 4.4 ± 2.1 days. Mean number of complications was 0.7 ± 1.1, with 30.4% of patients having had at least 1 complication. The 30-day all-cause readmission rate was 5.4%, and 30-day reoperation rate was 3.6%. For 30 patients (54%) with 1-year PROs, mean preoperative ODI was 65.2 ± 11.1, and mean preoperative VAS was 6.6 ± 1.6. Mean ODI change was -19.9 ± 20.1 (P < .001), and mean VAS change was -2.6 ± 2.3 (P < .001). A total of 15 patients (50%) achieved the minimum clinically important difference in ODI (12.8), with a mean follow-up of 18.9 months.

Conclusions

Patients with extreme obesity who undergo thoracolumbar fusion have acceptable 30-day adverse events and potentially can achieve significant improvement in pain and disability.

Spine Registries: Where Do We Stand?

To curb the unsustainable rise in health care costs, novel payment models are being explored which focus on value rather than volume. Underlying this reform is an accurate understanding of costs and outcomes. The Patient Protection and Affordable Care Act, the Institute of Medicine, and the Agency for Healthcare Research and Quality have specifically advocated for the use of registries to help define the real-world effectiveness of surgical interventions to help guide health care reform. Registries can help define value by documenting surgical efficacy, and specifically by reporting patient-based outcome measures. Over the past 10 years, several spine registries have been initiated and some others have expanded. These are providing a repository of evidence for surgical value. Herein, we will review the components of a well-designed registry and provide examples of such registries and their impact on health care delivery.

Variability in the utility of predictive models in predicting patient-reported outcomes following spine surgery for degenerative conditions: a systematic review

OBJECTIVE

There is increasing emphasis on patient-reported outcomes (PROs) to quantitatively evaluate quality outcomes from degenerative spine surgery. However, accurate prediction of PROs is challenging due to heterogeneity in outcome measures, patient characteristics, treatment characteristics, and methodological characteristics. The purpose of this study was to evaluate the current landscape of independently validated predictive models for PROs in elective degenerative spinal surgery with respect to study design and model generation, training, accuracy, reliability, variance, and utility.

METHODS

The authors analyzed the current predictive models in PROs by performing a search of the PubMed and Ovid databases using PRISMA guidelines and a PICOS (participants, intervention, comparison, outcomes, study design) model. They assessed the common outcomes and variables used across models as well as the study design and internal validation methods.

RESULTS

A total of 7 articles met the inclusion criteria, including a total of 17 validated predictive models of PROs after adult degenerative spine surgery. National registry databases were used in 4 of the studies. Validation cohorts were used in 2 studies for model verification and 5 studies used other methods, including random sample bootstrapping techniques. Reported c-index values ranged from 0.47 to 0.79. Two studies report the area under the curve (0.71–0.83) and one reports a misclassification rate (9.9%). Several positive predictors, including high baseline pain intensity and disability, demonstrated high likelihood of favorable PROs.

CONCLUSIONS

A limited but effective cohort of validated predictive models of spine surgical outcomes had proven good predictability for PROs. Instruments with predictive accuracy can enhance shared decision-making, improve rehabilitation, and inform best practices in the setting of heterogeneous patient characteristics and surgical factors.

Correlation of 2-year SRS-22r and ODI patient-reported outcomes with 5-year patient-reported outcomes after complex spinal fusion: a 5-year single-institution study of 118 patients

OBJECTIVE

Patient-reported outcomes (PROs) are often measured up to 2 years after surgery; however, prospective collection of longitudinal outcomes for 5 years postoperatively can be challenging due to lack of patient follow-up. The aim of this study was to determine whether PROs collected at 2-year follow-up accurately predict long-term PROs 5 years after complex spinal fusion (≥ 5 levels).

METHODS

This was an ambispective study of 118 adult patients (≥ 18 years old) undergoing ≥ 5-level spinal arthrodesis to the sacrum with iliac fixation from January 2002 to December 2011. Patient demographics and radiographic parameters as well as intraoperative variables were collected. PRO instruments (Scoliosis Research Society [SRS]-22r function, self-image, mental health, pain, and Oswestry Disability Index [ODI]) were completed before surgery then at 2 and 5 years after surgery. Primary outcome investigated in this study was the correlation between SRS-22r domains and ODI collected at 2- and 5-year follow-up.

RESULTS

Of the 118 patients, 111 patients had baseline PROs, 105 patients had 2-year follow-up data, and 91 patients had 5-year follow-up PRO data with 72% undergoing revision surgery. The average pre- and postoperative major coronal curve Cobb angles for the cohort were 32.1° ± 23.7° and 19.8° ± 19.3°, respectively. There was a strong correlation between 2- and 5-year ODI (r2 = 0.80, p < 0.001) and between 2- and 5-year SRS-22r domains, including function (r2 = 0.79, p < 0.001), self-image (r2 = 0.82, p < 0.001), mental health (r2 = 0.77, p < 0.001), and pain (r2 = 0.79, p < 0.001). Of the PROs, ODI showed the greatest absolute change from baseline to 2- and 5-year follow-up (2-year Δ 17.6 ± 15.9; 5-year Δ 16.5 ± 19.9) followed by SRS-22r self-image (2-year Δ 1.4 ± 0.96; 5-year Δ 1.3 ± 1.0), pain (2-year Δ 0.94 ± 0.97; 5-year Δ 0.80 ± 1.0), function (2-year Δ 0.60 ± 0.62; 5-year Δ 0.49 ± 0.79), and mental health (2-year Δ 0.49 ± 0.77; 5-year Δ 0.38 ± 0.84).

CONCLUSIONS

Patient-reported outcomes collected at 2-year follow-up may accurately predict long-term PROs (5-year follow-up).

Does the severity of pain correlate with severity of functional disability? Factors influencing 'patient reported outcome measures' in spinal patients

Aims: To assess correlation between the Visual Analogue Scale (VAS) pain score and the Oswestry Disability Index (ODI) and which patient factors can influence patient-reported outcome measures (PROMs). This study also aims to assess the response to the sexual function question of the ODI.

Methods: Retrospective analysis of 200 consecutive patients undergoing a range of different lumbar spinal procedures between July 2012 and September 2015 was performed. Subgroup analysis was also performed on the 122 patients who underwent microdiscectomy and/or decompression procedures only. Data from notes and clinical letters from the patient's first clinic appointment were collected. In addition to these outcome measures, data were also extracted regarding patients' gender, age, smoking status, alcohol use, employment and mental health status.

Results: Significant correlation was found between VAS pain score and ODI (p = 0.002) and between VAS pain score and question 1 of ODI (p = 0.0001). A lower ODI score was reported at time of surgery by those in employment compared to those who are unemployed (p = 0.008). In addition to this, a lower ODI score was reported in those who are self-employed compared to those in employment (p = 0.048) in both cohorts. A significantly higher mean ODI score was shown within the subgroup analysis for current smokers (p = 0.02). None of the other patient factors that were analysed were found to affect PROMs. 65% of patients answered the sexual function question of the ODI.

Conclusions: Significant correlation was demonstrated between VAS pain score and ODI. Those who are in employment are far more likely to report a lower ODI score than those who are unemployed at the time of surgery. Self-employed patients were found to have reported a significantly lower ODI score than those who are in employment. Smoking cessation should be encouraged as those who are current smokers may be more likely to report a higher ODI. As 65% of patients decided to answer the sexual function question of the ODI, this supports its further use.

Association between preoperative activity level and functional outcome at 12 months following surgical decompression for lumbar spinal stenosis

OBJECTIVE

This study defines the association of preoperative physical activity level with functional outcomes at 3 and 12 months following surgical decompression for lumbar spinal stenosis.

METHODS

Data were collected as a prospective observational registry at a single institution from 2012 through 2015, and then analyzed with a retrospective cohort design. Patients who were able to participate in activities outside the home preoperatively were compared to patients who did not participate in such activities, with respect to 3-month and 12-month functional outcomes postintervention, adjusted for relevant confounders.

RESULTS

Ninety-nine patients were included. At baseline, sedentary/inactive patients (n = 55) reported greater back pain, lower quality of life, and higher disability than similarly treated patients who were active preoperatively. Both cohorts experienced significant improvement from baseline in back pain, leg pain, disability, and quality of life at both 3 and 12 months after lumbar decompression surgery. At 3 months postintervention, sedentary/inactive patients reported more leg pain and worse disability than patients who performed activities outside the home preoperatively. However, at 12 months postintervention, there were no statistically significant differences between the two cohorts in back pain, leg pain, quality of life, or disability. Multivariate analysis revealed that sedentary/inactive patients had improved disability and higher quality of life after surgery compared to baseline. Active patients experienced greater overall improvement in disability compared to inactive patients.

CONCLUSIONS

Sedentary/inactive patients have a more protracted recovery after lumbar decompression surgery for spinal stenosis, but at 12 months postintervention can expect to reach similar long-term outcomes as patients who are active/perform activities outside the home preoperatively.

Determination of minimally clinically important differences for JOABPEQ measure after discectomy in patients with lumbar disc herniation

Background

It is crucial to define if changes in patient-reported outcome (PRO) measure correspond to relevant clinical improvements. Aim of this study was to determine minimally clinically important differences (MCID) of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) in patients with lumbar disc herniation (LDH) to assess surgical success.

Methods

A total of 127 patients with LDH consecutively referred to our clinic were enrolled into this prospective study between March 2012 and August 2015. All participants completed the JOABPEQ and the Oswestry Disability Index (ODI) score before surgery, and at 1 year after surgery. Surgical success was defined based on clinical consensus of the team and be used as anchor. The MCID value of the JOABPEQ subscales were estimated using two anchor-based methods: (I) average change procedure (responsiveness); and (II) receiver operating characteristic (ROC) curve analysis.

Results

The mean age of patients was 51.2±9.4 years, and there were 68 (53.5%) male. A total of 83.5% (106 cases) showed improvement based on the clinical consensus of the spine surgeon team at last follow-up. To assess surgical success, the two MCID calculation methods generated two optimal prediction thresholds on the JOABPEQ subscales (low back pain: 19.1, 22.4; lumbar function: 21.3, 24.2; walking ability: 24.5, 27.9; social life function: 14.3, 17.1; and mental health: 12.8, 14.8) for ROC analysis and average change procedure, respectively (P<0.002 for all of subscales in two methods). For all five subscales, the sensitivity and specificity were between 61.2 and 81.1 with AUC greater than 0.70.

Conclusions

These findings support the value of the MCID to assess surgical success for the JOABPEQ subscales in patients with LDH. This estimate may be a useful tool in clinical practice.

How does patient-rated outcome change over time following the surgical treatment of degenerative disorders of the thoracolumbar spine?

PURPOSE

Patient-rated measures are considered the gold standard for assessing the outcome of spine surgery, but there is no consensus on the appropriate timing of follow-up. Journals often demand a minimum 2-year follow-up, but the indiscriminate application of this principle may not be warranted. We examined the course of change in patient outcomes up to 5 years after surgery for degenerative spinal disorders.

METHODS

The data were evaluated from 4287 consecutive patients (2287 women, 2000 men; aged 62 ± 15 years) with degenerative disorders of the thoracolumbar spine, undergoing first-time surgery at the given level between 01/01/2005 and 31/12/2011. The Core Outcome Measures Index (COMI; scored 0-10) was completed by 4012 (94%) patients preoperatively, 4008 (93%) at 3-month follow-up, 3897 (91%) at 1-year follow-up, 3736 (87%) at 2-year follow-up, and 3387 (79%) at 5-year follow-up. 2959 (69%) completed the COMI at all five time-points.

RESULTS

The individual COMI change scores from preoperatively to the various follow-up time-points showed significant correlations ranging from r = 0.50 (for change scores at the earliest vs the latest follow-up) to r = 0.75 (for change scores after 12- vs 24-month follow-up). Concordance with respect to whether the minimum clinically important change score was achieved at consecutive time-points was also good (70-82%). COMI decreased significantly (p < 0.05) from preop to 3 months (by 3.6 ± 2.8 points) and from 3 to 12 months (by 0.3 ± 2.4 points), then levelled off up to 5 years (0.04-0.05 point change; p > 0.05). The course of change up to 12 months differed slightly (p < 0.05) depending on pathology/whether fusion was carried out. For patients undergoing simple decompression, 3-month follow-up was sufficient; those undergoing fusion continued to show further slight but significant change up to 12 months.

CONCLUSIONS

Stable group mean COMI scores were observed for all patients from 12 months postoperatively onwards. The early postoperative results appeared to herald the longer term outcome. As such, a 'wait and see policy' in patients with a poor initial outcome at 3 months is not advocated. The insistence on a 2-year follow-up could result in a failure to intervene early to achieve better long-term outcomes.

Need for Two-Year Patient-Reported Outcomes Score for Lumbar Spine Surgery Is Procedure-Specific: Analysis From a Prospective Longitudinal Spine Registry

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

The aim of this study was to determine whether 1-year patient-reported outcomes (PROs) can accurately assess effective care for patients undergoing surgery for degenerative lumbar spine disease.

SUMMARY OF BACKGROUND DATA

Prospective longitudinal PROs registries provide a means to accurately assess outcomes and determine the relative effectiveness of various spine treatments. Obtaining long-term PROs can be costly and challenging.

METHODS

Patients enrolled into a prospective registry who underwent lumbar spine surgery for degenerative disease were included. Baseline, 1-year, and 2-year Oswestry Disability Index (ODI) scores were captured. Previously published minimum clinically important difference (MCID) for ODI (14.9) was used. Multivariable linear regression model was created to derive model-estimated 2-year ODI scores. Absolute differences between 1-year and 2-year ODI were compared to absolute differences between 2-year and model-estimated 2-year ODI. Concordance rates in achieving MCID at 1-year and 2-year and predictive values were calculated.

RESULTS

A total of 868 patients were analyzed. One-year ODI scores differed from 2-year scores by an absolute difference of 9.7 ± 8.9 points and predictive model-estimated 2-year scores differed from actual 2-year scores by 8.8 ± 7.3 points. The model-estimated 2-year ODI was significantly different than actual 1-year ODI in assessing actual 2-year ODI for all procedures (P = 0.001) except for primary (P = 0.932) and revision microdiscectomy (P = 0.978) and primary laminectomy (P = 0.267). The discordance rates of achieving or not achieving MCID for ODI ranged from 8% to 27%. Concordance rate was about 90% for primary and revision microdiscectomy. The positive and negative predictive value of 1-year ODI to predict 2-year ODI was 83% and 67% for all procedures and 92% and 67% for primary and 100% and 86% for revision microdiscectomy respectively.

CONCLUSION

One-year disability outcomes can potentially estimate 2-year outcomes for patient populations, but cannot reliably predict 2-year outcomes for individual patients, except for patients undergoing primary and revision microdiscectomy.

LEVEL OF EVIDENCE

4.

Defining the "Substantial Clinical Benefit" After Arthroscopic Treatment of Femoroacetabular Impingement

BACKGROUND

The minimal clinically important difference (MCID) has been defined in orthopaedics and is the smallest change that a patient considers meaningful. Less is known about improvements that the patient perceives as clinically considerable, or the substantial clinical benefit (SCB). For the young, highly functioning patient cohort with femoroacetabular impingement (FAI), the SCB is an important measure of clinical success.

PURPOSE

To derive the SCB for FAI treatment and identify outcome score thresholds and patient variables predictive of the SCB.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

The modified Harris Hip Score (mHHS), the Hip Outcome Score activities of daily living (HOS-ADL) and sport (HOS-Sport) subscales, and the international Hip Outcome Tool (iHOT-33) were prospectively administered to 364 patients with a minimum 1-year follow-up. At 1 year postoperatively, patients graded their hip function based on several anchor responses such as "no change" and "much improved." The SCB was defined as the change on each outcome tool that equated to the difference between "no change" and "much improved" on the health transition question. Receiver operating characteristic analysis with area under the curve (AUC) was used to identify optimal values that were most representative of the SCB. Multivariable analysis identified patient variables predictive of the SCB.

RESULTS

The net change in outcome scores corresponding to the SCB for the mHHS, HOS-ADL, HOS-Sport, and iHOT-33 was 19.8, 10.0, 29.9, and 24.5, respectively. The following postoperative outcome scores demonstrated excellent distinction (AUC >0.8) between "no change" and "much improved" and thus were considered absolute values for the postoperative SCB: 82.5 (mHHS), 93.3 (HOS-ADL), 84.4 (HOS-Sport), and 63.5 (iHOT-33). Preoperative scores on the HOS-ADL (83.3) and HOS-Sport (50.0) were significant threshold cutoffs, above which attaining the SCB became less likely. Younger age and lower Outerbridge grade were predictive of achieving the SCB.

CONCLUSION

The SCB has not been previously defined in the hip preservation literature and is complementary to the MCID as the upper bound for clinically significant improvement. We identified predictive preoperative and diagnostic postoperative outcome scores for the SCB that can be used to manage patient expectations and grade outcomes. These findings are objective criteria for defining clinical success after arthroscopic FAI treatment.

Trends in the use of patient-reported outcome instruments in neurosurgical adult thoracolumbar deformity and degenerative disease literature

Objective:

Shifting national healthcare trends place increased emphasis on patient-centered care and value-based outcomes, and thus, patient-reported outcome instruments (PROIs) are often used. We sought to characterize the trends in PROI use over the past decade with regard to thoracolumbar degenerative spine disease and spinal deformity in major neurosurgical journals.

Methods:

Articles were screened for PROI use through a PubMed search among five major neurosurgical journals from 2006 to 2016. Articles focusing on adult thoracolumbar deformity and degenerative disease were selected with stringent criteria to further characterize PROI use.

Results:

A total of 29 different PROIs were used among 102 articles identified from 2006 to 2016 using our search strategy. Journal of Neurosurgery: Spine contained the most articles utilizing PROIs with 35.3% of all articles meeting search criteria. The most frequently used PROIs were Oswestry Disability Index, visual analog scale, and the European Quality of Life Five-dimension questionnaire used in 79.4%, 59.8%, and 29.4% of articles, respectively. Linear regression identified a significant increase in the number of articles employing PROIs from 2006 to 2016 (Y = 1.85, R²= 0.77, P < 0.01). The total number of PROIs per article was relatively stagnant over time and did not significantly change (Y = 0.03, R²= 0.05, P = 0.51).

Conclusions:

PROI use as an outcome tool in the adult thoracolumbar disease literature has increased during the past decade, which may be an indicative of PROI use to define patient expectations. This may also represent a trend toward PROI use as a surrogate measure of value-based care.