Predictive value of 3-month lumbar discectomy outcomes in the NeuroPoint-SD Registry

Objective outcome measures may demonstrate continued change in functional recovery in patients with ceiling effects of subjective patient-reported outcome measures after surgery for lumbar degenerative disorders

BACKGROUND CONTEXT

The 6-minute walking test (6WT) has been previously shown to be a reliable and valid outcome measure. It is unclear if the 6WT may further help to detect differences in well performing patients that reach a ceiling effect in PROMs after surgery.

PURPOSE

To evaluate changes and timing of change in objective functional impairment (OFI) as measured with the smartphone-based 6WT in relation to patient-reported outcome measures (PROMs) after surgery for degenerative lumbar disorders (DLD).

STUDY DESIGN

Prospective observational cohort study.

PATIENT SAMPLE

Fifty consecutive patients undergoing surgery for DLD.

OUTCOME MEASURES

Patients self-determined their OFI using the 6WT application (6WT-app) and completed a set of paper-based PROMs before, 6 weeks and 3 months after surgery.

METHODS

Fifty patients undergoing surgery for DLD were assessed preoperatively (baseline), 6 weeks (6W) and 3 months (3M) postoperatively. Paired sample t-tests were used to establish significant changes in raw 6-minute walking distance (6WD) and standardized Z-scores, as well as PROMs. Pearson correlation coefficient was used to define the relationship between 6WT and PROMs. Floor and ceiling effects were assessed for each PROM (visual analogue scale [VAS], core outcome measure index [COMI], Zurich claudication questionnaire [ZCQ]).

RESULTS

Mean 6WT results improved from 377 m (standard deviation - SD 137; Z-score: 1.8, SD 1.8) to 490 m (SD 126; -0.7, SD 1.5) and 518 m (SD 112; -0.4, SD 1.41; all p<.05) at 6W and 3M follow-up. No significant improvement was observed between 6W and 3M for the ZCQ, VAS back and leg pain. While correlation between 6WT and all PROMs were weak at baseline, correlation coefficient increased to moderate at 3M. A considerable ceiling effect (best possible score) was observed, most notably for the ZCQ physical performance, VAS back and leg pain in 24%, 20%, and 16% of patient at 6W and in 30%, 24%, and 28% at 3M.

CONCLUSIONS

Objective functional tests can describe the continued change in the physical recovery of a patient and may help to detect differences in well performing groups as well as in cases where patients' PROM results cannot further improve because of a ceiling effect.

A Proposed Personalized Spine Care Protocol (SpineScreen) to Treat Visualized Pain Generators: An Illustrative Study Comparing Clinical Outcomes and Postoperative Reoperations between Targeted Endoscopic Lumbar Decompression Surgery, Minimally Invasive TLIF and Open Laminectomy

Background: Endoscopically visualized spine surgery has become an essential tool that aids in identifying and treating anatomical spine pathologies that are not well demonstrated by traditional advanced imaging, including MRI. These pathologies may be visualized during endoscopic lumbar decompression (ELD) and categorized into primary pain generators (PPG). Identifying these PPGs provides crucial information for a successful outcome with ELD and forms the basis for our proposed personalized spine care protocol (SpineScreen). Methods: a prospective study of 412 patients from 7 endoscopic practices consisting of 207 (50.2%) males and 205 (49.8%) females with an average age of 63.67 years and an average follow-up of 69.27 months was performed to compare the durability of targeted ELD based on validated primary pain generators versus image-based open lumbar laminectomy, and minimally invasive lumbar transforaminal interbody fusion (TLIF) using Kaplan-Meier median survival calculations. The serial time was determined as the interval between index surgery and when patients were censored for additional interventional and surgical treatments for low back-related symptoms. A control group was recruited from patients referred for a surgical consultation but declined interventional and surgical treatment and continued on medical care. Control group patients were censored when they crossed over into any surgical or interventional treatment group. Results: of the 412 study patients, 206 underwent ELD (50.0%), 61 laminectomy (14.8%), and 78 (18.9%) TLIF. There were 67 patients in the control group (16.3% of 412 patients). The most common surgical levels were L4/5 (41.3%), L5/S1 (25.0%), and L4-S1 (16.3%). At two-year f/u, excellent and good Macnab outcomes were reported by 346 of the 412 study patients (84.0%). The VAS leg pain score reduction was 4.250 ± 1.691 (p < 0.001). No other treatment during the available follow-up was required in 60.7% (125/206) of the ELD, 39.9% (31/78) of the TLIF, and 19.7% (12/61 of the laminectomy patients. In control patients, only 15 of the 67 (22.4%) control patients continued with conservative care until final follow-up, all of which had fair and poor functional Macnab outcomes. In patients with Excellent Macnab outcomes, the median durability was 62 months in ELD, 43 in TLIF, and 31 months in laminectomy patients (p < 0.001). The overall survival time in control patients was eight months with a standard error of 0.942, a lower boundary of 6.154, and an upper boundary of 9.846 months. In patients with excellent Macnab outcomes, the median durability was 62 months in ELD, 43 in TLIF, and 31 months in laminectomy patients versus control patients at seven months (p < 0.001). The most common new-onset symptom for censoring was dysesthesia ELD (9.4%; 20/206), axial back pain in TLIF (25.6%;20/78), and recurrent pain in laminectomy (65.6%; 40/61) patients (p < 0.001). Transforaminal epidural steroid injections were tried in 11.7% (24/206) of ELD, 23.1% (18/78) of TLIF, and 36.1% (22/61) of the laminectomy patients. The secondary fusion rate among ELD patients was 8.8% (18/206). Among TLIF patients, the most common additional treatments were revision fusion (19.2%; 15/78) and multilevel rhizotomy (10.3%; 8/78). Common follow-up procedures in laminectomy patients included revision laminectomy (16.4%; 10/61), revision ELD (11.5%; 7/61), and multilevel rhizotomy (11.5%; 7/61). Control patients crossed over into ELD (13.4%), TLIF (13.4%), laminectomy (10.4%) and interventional treatment (40.3%) arms at high rates. Most control patients treated with spinal injections (55.5%) had excellent and good functional outcomes versus 40.7% with fair and poor (3.7%), respectively. The control patients (93.3%) who remained in medical management without surgery or interventional care (14/67) had the worst functional outcomes and were rated as fair and poor. Conclusions: clinical outcomes were more favorable with lumbar surgeries than with non-surgical control groups. Of the control patients, the crossover rate into interventional and surgical care was 40.3% and 37.2%, respectively. There are longer symptom-free intervals after targeted ELD than with TLIF or laminectomy. Additional intervention and surgical treatments are more often needed to manage new-onset postoperative symptoms in TLIF- and laminectomy compared to ELD patients. Few ELD patients will require fusion in the future. Considering the rising cost of surgical spine care, we offer SpineScreen as a simplified and less costly alternative to traditional image-based care models by focusing on primary pain generators rather than image-based criteria derived from the preoperative lumbar MRI scan.

Spine surgery complexity score predicts outcomes in 671 consecutive spine surgery patients

Background:

The spine surgery complexity score (SSCS), previously reported by us, is a simple grading system to predict postoperative complications and hospital length of stay (LOS). This scale is based on the technical difficulty of the spinal procedures being performed.

Methods:

We performed a retrospective chart review to validate SSCS in 671 consecutive patients undergoing spine procedures at a quaternary academic hospital.

Results:

The SSCS was predictive of the hospital LOS and postoperative complications (defined by the ClavienDindo score), based on linear regression analysis (P < 0.001 for both).

Conclusion:

Categorizing procedures according to the SSCS may enable neurosurgeons to assess surgical risk and predict longer LOS courses after spine surgery. Thus, it may prove useful in preoperative patient evaluation/ education and determining a prognosis based on surgical complexity.

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.

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.

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.

Criteria for failure and worsening after surgery for lumbar disc herniation: a multicenter observational study based on data from the Norwegian Registry for Spine Surgery

PURPOSE

In clinical decision-making, it is crucial to discuss the probability of adverse outcomes with the patient. A large proportion of the outcomes are difficult to classify as either failure or success. Consequently, cutoff values in patient-reported outcome measures (PROMs) for "failure" and "worsening" are likely to be different from those of "non-success". The aim of this study was to identify dichotomous cutoffs for failure and worsening, 12 months after surgical treatment for lumbar disc herniation, in a large registry cohort.

METHODS

A total of 6840 patients with lumbar disc herniation were operated and followed for 12 months, according to the standard protocol of the Norwegian Registry for Spine Surgery (NORspine). Patients reporting to be unchanged or worse on the Global Perceived Effectiveness (GPE) scale at 12-month follow-up were classified as "failure", and those considering themselves "worse" or "worse than ever" after surgery were classified as "worsening". These two dichotomous outcomes were used as anchors in analyses of receiver operating characteristics (ROC) to define cutoffs for failure and worsening on commonly used PROMs, namely, the Oswestry Disability Index (ODI), the EuroQuol 5D (EQ-5D), and Numerical Rating Scales (NRS) for back pain and leg pain.

RESULTS

"Failure" after 12 months for each PROM, as an insufficient improvement from baseline, was (sensitivity and specificity): ODI change <13 (0.82, 0.82), ODI% change <33% (0.86, 0.86), ODI final raw score >25 (0.89, 0.81), NRS back-pain change <1.5 (0.74, 0.86), NRS back-pain % change <24 (0.85, 0.81), NRS back-pain final raw score >5.5 (0.81, 0.87), NRS leg-pain change <1.5 (0.81, 0.76), NRS leg-pain % change <39 (0.86, 0.81), NRS leg-pain final raw score >4.5 (0.91, 0.85), EQ-5D change <0.10 (0.76, 0.83), and EQ-5D final raw score >0.63 (0.81, 0.85). Both a final raw score >48 for the ODI and an NRS >7.5 were indicators for "worsening" after 12 months, with acceptable accuracy.

CONCLUSION

The criteria with the highest accuracy for defining failure and worsening after surgery for lumbar disc herniation were an ODI percentage change score <33% for failure and a 12-month ODI raw score >48. These cutoffs can facilitate shared decision-making among doctors and patients, and improve quality assessment and comparison of clinical outcomes across surgical units. In addition to clinically relevant improvements, we propose that rates of failure and worsening should be included in reporting from clinical trials.

Relationship between size of disc and early postoperative outcomes after lumbar discectomy

BACKGROUND

Previous studies suggest that patients with larger disc herniations (greater than 6 mm) will have better outcomes following discectomy. This has not been validated in a large series of patients.

PURPOSE

We sought to empirically evaluate this relationship in a series of patients who had data collected prospectively as part of a randomized trial.

METHODS

This retrospective review included 63 consecutive adult patients who underwent a single-level, primary lumbar discectomy. Outcomes were VAS for leg and back pain and the modified oswestry disability index (MODI). Statistical tests were used to compare patients using different cutoffs of preoperative disc diameters and disc volume removed. Regression analysis was performed to determine if there was a relationship between outcomes and the measured parameters.

RESULTS

While patients who achieved substantial clinical benefit (SCB) for MODI had larger disc diameters, this relationship was not found for leg or back pain for any of the measured parameters. Using 5, 6, 7, or 8 mm as a cutoff for disc diameter demonstrated no differences. Regression analysis did not demonstrate a significant relationship between disc volume removed and final MODI scores.

CONCLUSION

While patients with larger disc herniations on average might have a greater likelihood of superior clinical outcomes, the previously suggested "6 mm rule" was not supported.

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

OBJECTIVE Prospective longitudinal outcomes registries are at the center of evidence-driven health care reform. Obtaining real-world outcomes data at 12 months can be costly and challenging. In the present study, the authors analyzed whether 3-month outcome measurements sufficiently represent 12-month outcomes for patients with degenerative lumbar disease undergoing surgery. METHODS Data from 3073 patients undergoing elective spine surgery for degenerative lumbar disease were entered into a prospective multicenter registry (N(2)QOD). Baseline, 3-month, and 12-month follow-up Oswestry Disability Index (ODI) scores were recorded. The absolute differences between actual 12- and 3-month ODI scores was evaluated. Additionally, the authors analyzed the absolute difference between actual 12-month ODI scores and a model-predicted 12-month ODI score (the model used patients' baseline characteristics and actual 3-month scores). The minimal clinically important difference (MCID) for ODI of 12.8 points and the substantial clinical benefit (SCB) for ODI of 18.8 points were used based on the previously published values. The concordance rate of achieving MCID and SCB for ODI at 3-and 12-months was computed. RESULTS The 3-month ODI scores differed from 12-month scores by an absolute difference of 11.9 ± 10.8, and predictive modeling estimations of 12-month ODI scores differed from actual 12-month scores by a mean (± SD) of 10.7 ± 9.0 points (p = 0.001). Sixty-four percent of patients (n = 1982) achieved an MCID for ODI at 3 months in comparison with 67% of patients (n = 2088) by 12 months; 51% (n = 1731) and 61% (n = 1860) of patients achieved SCB for ODI at 3 months and 12 months, respectively. Almost 20% of patients had ODI scores that varied at least 20 points (the point span of an ODI functional category) between actual 3- and 12-month values. In the aggregate analysis of achieving MCID, 77% of patients were concordant and 23% were discordant in achieving or not achieving MCID at 3 and 12 months. The discordance rates of achieving or not achieving MCID for ODI were in the range of 19% to 27% for all diagnoses and treatments (decompression with and without fusion). The positive and negative predictive value of 3-months ODI to predict 12-month ODI was 86% and 60% for MCID and 82% and 67% for SCB. CONCLUSIONS Based on their findings, the authors conclude the following: 1) Predictive methods for functional outcome based on early patient experience (i.e., baseline and/or 3-month data) should be used to help evaluate the effectiveness of procedures in patient populations, rather than serving as a proxy for long-term individual patient experience. 2) Prospective longitudinal registries need to span at least 12 months to determine the effectiveness of spine care at the individual patient and practitioner level.