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OBJECTIVE Deficiency in patient education has been correlated with increased disease-related morbidity and decreased access to care. However, the associations between educational level, preoperative disease severity, and postoperative outcomes in patients with lumbar spondylolisthesis have yet to be explored. METHODS The spondylolisthesis dataset of the Quality Outcomes Database (QOD)—a cohort with prospectively collected data by the SpineCORe study team of the 12 highest enrolling sites with an 81% follow-up at 5 years —was utilized and stratified for educational level. Patients were classified into three categories (high school or less, graduate, or postgraduate). Patient-reported outcome measures (PROMs) documented at baseline and follow-up included Oswestry Disability Index (ODI) score, EQ-5D in quality-adjusted life years, and numeric rating scale (NRS) scores for back and leg pain. Disease severity was measured with PROMs. Postoperatively, patients also completed the North American Spine Society assessment to measure their satisfaction with surgery. Multivariable regression analysis was used to compare education level with disease severity and postoperative outcomes. RESULTS A total of 608 patients underwent analysis, with 260 individuals (42.8%) at an educational level of high school or less. On univariate analysis, baseline disease severity was worse among patients with lower levels of education. On multivariable regression analysis, patients with postgraduate level of education had significantly lower ODI scores (β = −3.75, 95% CI −7.31 to −0.2, p = 0.039) compared to graduates, while the other PROMs were not associated with significant differences at baseline. Five years postoperatively, patients from various educational backgrounds exhibited similar rates of minimal clinically important differences in PROMs. Nevertheless, patients with the lowest educational level had higher ODI scores (27.1, p < 0.01), lower EQ-5D scores (0.701, p < 0.01), and higher NRS leg pain (3.0, p < 0.01) and back pain (4.0, p < 0.01) scores compared to those with graduate or postgraduate levels of education. The odds for postoperative satisfaction were also comparable between cohorts at 5 years (reference, graduate level; high school or less, OR 0.87, 95% CI 0.46–1.64, p = 0.659; postgraduate, OR 1.6, 95% CI 0.7–3.65, p = 0.262). CONCLUSIONS Lower patient education level was associated with a greater baseline disease severity in patients with lumbar spondylolisthesis. Surgery demonstrated similar benefits irrespective of educational background; however, individuals with lower educational level reported lower outcomes overall. This emphasizes the need for enhanced health literacy to mitigate disparities for reported outcomes.

OBJECTIVE Spondylolisthesis is a common operative disease in the United States, but robust predictive models for patient outcomes remain limited. The development of models that accurately predict postoperative outcomes would be useful to help identify patients at risk of complicated postoperative courses and determine appropriate healthcare and resource utilization for patients. As such, the purpose of this study was to develop k-nearest neighbors (KNN) classification algorithms to identify patients at increased risk for extended hospital length of stay (LOS) following neurosurgical intervention for spondylolisthesis. METHODS The Quality Outcomes Database (QOD) spondylolisthesis data set was queried for patients receiving either decompression alone or decompression plus fusion for degenerative spondylolisthesis. Preoperative and perioperative variables were queried, and Mann-Whitney U-tests were performed to identify which variables would be included in the machine learning models. Two KNN models were implemented (k = 25) with a standard training set of 60%, validation set of 20%, and testing set of 20%, one with arthrodesis status (model 1) and the other without (model 2). Feature scaling was implemented during the preprocessing stage to standardize the independent features. RESULTS Of 608 enrolled patients, 544 met prespecified inclusion criteria. The mean age of all patients was 61.9 ± 12.1 years (± SD), and 309 (56.8%) patients were female. The model 1 KNN had an overall accuracy of 98.1%, sensitivity of 100%, specificity of 84.6%, positive predictive value (PPV) of 97.9%, and negative predictive value (NPV) of 100%. Additionally, a receiver operating characteristic (ROC) curve was plotted for model 1, showing an overall area under the curve (AUC) of 0.998. Model 2 had an overall accuracy of 99.1%, sensitivity of 100%, specificity of 92.3%, PPV of 99.0%, and NPV of 100%, with the same ROC AUC of 0.998. CONCLUSIONS Overall, these findings demonstrate that nonlinear KNN machine learning models have incredibly high predictive value for LOS. Important predictor variables include diabetes, osteoporosis, socioeconomic quartile, duration of surgery, estimated blood loss during surgery, patient educational status, American Society of Anesthesiologists grade, BMI, insurance status, smoking status, sex, and age. These models may be considered for external validation by spine surgeons to aid in patient selection and management, resource utilization, and preoperative surgical planning.

OBJECTIVE Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has been used to treat degenerative lumbar spondylolisthesis and is associated with expedited recovery, reduced operative blood loss, and shorter hospitalizations compared to those with traditional open TLIF. However, the impact of MI-TLIF on long-term patient-reported outcomes (PROs) is less clear. Here, the authors compare the outcomes of MI-TLIF to those of traditional open TLIF for grade I degenerative lumbar spondylolisthesis at 60 months postoperatively. METHODS The authors utilized the prospective Quality Outcomes Database registry and queried for patients with grade I degenerative lumbar spondylolisthesis who had undergone single-segment surgery via an MI or open TLIF method. PROs were compared 60 months postoperatively. The primary outcome was the Oswestry Disability Index (ODI). The secondary outcomes included the numeric rating scale (NRS) for back pain (NRS-BP), NRS for leg pain (NRS-LP), EQ-5D, North American Spine Society (NASS) satisfaction, and cumulative reoperation rate. Multivariable models were constructed to assess the impact of MI-TLIF on PROs, adjusting for variables reaching p < 0.20 on univariable analyses and respective baseline PRO values. RESULTS The study included 297 patients, 72 (24.2%) of whom had undergone MI-TLIF and 225 (75.8%) of whom had undergone open TLIF. The 60-month follow-up rates were similar for the two cohorts (86.1% vs 75.6%, respectively; p = 0.06). Patients did not differ significantly at baseline for ODI, NRS-BP, NRS-LP, or EQ-5D (p > 0.05 for all). Perioperatively, MI-TLIF was associated with less blood loss (108.8 ± 85.6 vs 299.6 ± 242.2 ml, p < 0.001) and longer operations (228.2 ± 111.5 vs 189.6 ± 66.5 minutes, p < 0.001) but had similar lengths of hospitalizations (MI-TLIF 2.9 ± 1.8 vs open TLIF 3.3 ± 1.6 days, p = 0.08). Discharge disposition to home or home health was similar (MI-TLIF 93.1% vs open TLIF 91.1%, p = 0.60). Both cohorts improved significantly from baseline for the 60-month ODI, NRS-BP, NRS-LP, and EQ-5D (p < 0.001 for all comparisons). In adjusted analyses, MI-TLIF, compared to open TLIF, was associated with similar 60-month ODI, ODI change, odds of reaching ODI minimum clinically important difference, NRS-BP, NRS-BP change, NRS-LP, NRS-LP change, EQ-5D, EQ-5D change, and NASS satisfaction (adjusted p > 0.05 for all). The 60-month reoperation rates did not differ significantly (MI-TLIF 5.6% vs open TLIF 11.6%, p = 0.14). CONCLUSIONS For symptomatic, single-level grade I degenerative lumbar spondylolisthesis, MI-TLIF was associated with decreased blood loss perioperatively, but there was no difference in 60-month outcomes for disability, back pain, leg pain, quality of life, or satisfaction between MI and open TLIF. There was no difference in cumulative reoperation rates between the two procedures. These results suggest that in appropriately selected patients, either procedure may be employed depending on patient and surgeon preferences.

OBJECTIVE Reduction of Meyerding grade is often performed during fusion for spondylolisthesis. Although radiographic appearance may improve, correlation with patient-reported outcomes (PROs) is rarely reported. In this study, the authors’ aim was to assess the impact of spondylolisthesis reduction on 24-month PRO measures after decompression and fusion surgery for Meyerding grade I degenerative lumbar spondylolisthesis. METHODS The Quality Outcomes Database (QOD) was queried for patients undergoing posterior lumbar fusion for spondylolisthesis with a minimum 24-month follow-up, and quantitative correlation between Meyerding slippage reduction and PROs was performed. Baseline and 24-month PROs, including the Oswestry Disability Index (ODI), EQ-5D, Numeric Rating Scale (NRS)–back pain (NRS-BP), NRS-leg pain (NRS-LP), and satisfaction (North American Spine Society patient satisfaction questionnaire) scores were noted. Multivariable regression models were fitted for 24-month PROs and complications after adjusting for an array of preoperative and surgical variables. Data were analyzed for magnitude of slippage reduction and correlated with PROs. Patients were divided into two groups: < 3 mm reduction and ≥ 3 mm reduction. RESULTS Of 608 patients from 12 participating sites, 206 patients with complete data were identified in the QOD and included in this study. Baseline patient demographics, comorbidities, and clinical characteristics were similarly distributed between the cohorts except for depression, listhesis magnitude, and the proportion with dynamic listhesis (which were accounted for in the multivariable analysis). One hundred four (50.5%) patients underwent lumbar decompression and fusion with slippage reduction ≥ 3 mm (mean 5.19, range 3 to 11), and 102 (49.5%) patients underwent lumbar decompression and fusion with slippage reduction < 3 mm (mean 0.41, range 2 to −2). Patients in both groups (slippage reduction ≥ 3 mm, and slippage reduction < 3 mm) reported significant improvement in all primary patient reported outcomes (all p < 0.001). There was no significant difference with regard to the PROs between patients with or without intraoperative reduction of listhesis on univariate and multivariable analyses (ODI, EQ-5D, NRS-BP, NRS-LP, or satisfaction). There was no significant difference in complications between cohorts. CONCLUSIONS Significant improvement was found in terms of all PROs in patients undergoing decompression and fusion for lumbar spondylolisthesis. There was no correlation with clinical outcomes and magnitude of Meyerding slippage reduction.

Abstract BACKGROUND Trials of lumbar spondylolisthesis are difficult to compare because of the heterogeneity in the populations studied. OBJECTIVE To define patterns of clinical presentation. METHODS This is a study of the prospective Quality Outcomes Database spondylolisthesis registry, including patients who underwent single-segment surgery for grade 1 degenerative lumbar spondylolisthesis. Twenty-four-month patient-reported outcomes (PROs) were collected. A k-means clustering analysis—an unsupervised machine learning algorithm—was used to identify clinical presentation phenotypes. RESULTS Overall, 608 patients were identified, of which 507 (83.4%) had 24-mo follow-up. Clustering revealed 2 distinct cohorts. Cluster 1 (high disease burden) was younger, had higher body mass index (BMI) and American Society of Anesthesiologist (ASA) grades, and globally worse baseline PROs. Cluster 2 (intermediate disease burden) was older and had lower BMI and ASA grades, and intermediate baseline PROs. Baseline radiographic parameters were similar ( P > .05). Both clusters improved clinically ( P < .001 all 24-mo PROs). In multivariable adjusted analyses, mean 24-mo Oswestry Disability Index (ODI), Numeric Rating Scale Back Pain (NRS-BP), Numeric Rating Scale Leg Pain, and EuroQol-5D (EQ-5D) were markedly worse for the high-disease-burden cluster (adjusted- P < .001). However, the high-disease-burden cluster demonstrated greater 24-mo improvements for ODI, NRS-BP, and EQ-5D (adjusted- P < .05) and a higher proportion reaching ODI minimal clinically important difference (MCID) (adjusted- P = .001). High-disease-burden cluster had lower satisfaction (adjusted- P = .02). CONCLUSION We define 2 distinct phenotypes—those with high vs intermediate disease burden—operated for lumbar spondylolisthesis. Those with high disease burden were less satisfied, had a lower quality of life, and more disability, more back pain, and more leg pain than those with intermediate disease burden, but had greater magnitudes of improvement in disability, back pain, quality of life, and more often reached ODI MCID.

OBJECTIVE The ideal surgical management of grade I lumbar spondylolisthesis has not been determined despite extensive prior investigations. In this cohort study, the authors used data from the large, multicenter, prospectively collected Quality Outcomes Database to bridge the gap between the findings in previous randomized trials and those in a more heterogeneous population treated in a typical practice. The objective was to assess the difference in patient-reported outcomes among patients undergoing decompression alone or decompression plus fusion. METHODS The primary outcome measure was change in 24-month Oswestry Disability Index (ODI) scores. The minimal clinically important difference (MCID) in ODI score change and 30% change in ODI score at 24 months were also evaluated. After adjusting for patient-specific and clinical factors, multivariable linear and logistic regressions were employed to evaluate the impact of fusion on outcomes. To account for differences in age, sex, body mass index, and baseline listhesis, a sensitivity analysis was performed using propensity score analysis to match patients undergoing decompression only with those undergoing decompression and fusion. RESULTS In total, 608 patients who had grade I lumbar spondylolisthesis were identified (85.5% with at least 24 months of follow-up); 140 (23.0%) underwent decompression alone and 468 (77.0%) underwent decompression and fusion. The 24-month change in ODI score was significantly greater in the fusion plus decompression group than in the decompression-only group (−25.8 ± 20.0 vs −15.2 ± 19.8, p < 0.001). Fusion remained independently associated with 24-month ODI score change (B = −7.05, 95% CI −10.70 to −3.39, p ≤ 0.001) in multivariable regression analysis, as well as with achieving the MCID for the ODI score (OR 1.767, 95% CI 1.058–2.944, p = 0.029) and 30% change in ODI score (OR 2.371, 95% CI 1.286–4.371, p = 0.005). Propensity score analysis resulted in 94 patients in the decompression-only group matched 1 to 1 with 94 patients in the fusion group. The addition of fusion to decompression remained a significant predictor of 24-month change in the ODI score (B = 2.796, 95% CI 2.228–13.275, p = 0.006) and of achieving the 24-month MCID ODI score (OR 2.898, 95% CI 1.214–6.914, p = 0.016) and 24-month 30% change in ODI score (OR 2.300, 95% CI 1.014–5.216, p = 0.046). CONCLUSIONS These results suggest that decompression plus fusion in patients with grade I lumbar spondylolisthesis may be associated with superior outcomes at 24 months compared with decompression alone, both in reduction of disability and in achieving clinically meaningful improvement. Longer-term follow-up is warranted to assess whether this effect is sustained.

Study Design. Retrospective analysis of a prospective registry. Objective. We utilized the Quality Outcomes Database (QOD) registry to investigate the “July Effect” at QOD spondylolisthesis module sites with residency trainees. Summary of Background Data. There is a paucity of investigation on the long-term outcomes following surgeries involving new trainees utilizing high-quality, prospectively collected data. Methods. This was an analysis of 608 patients who underwent single-segment surgery for grade 1 degenerative lumbar spondylolisthesis at 12 high-enrolling sites. Surgeries were classified as occurring in July or not in July (non-July). Outcomes collected included estimated blood loss, length of stay, operative time, discharge disposition, complications, reoperation and readmission rates, and patient-reported outcomes (Oswestry Disability Index [ODI], Numeric Rating Scale [NRS] Back Pain, NRS Leg Pain, EuroQol-5D [EQ-5D] and the North American Spine Society [NASS] Satisfaction Questionnaire). Propensity score-matched analyses were utilized to compare postoperative outcomes and complication rates between the July and non-July groups. Results. Three hundred seventy-one surgeries occurred at centers with a residency training program with 21 (5.7%) taking place in July. In propensity score-matched analyses, July surgeries were associated with longer operative times ( average treatment effect = 22.4 minutes longer, 95% confidence interval 0.9–449.0, P = 0.041). Otherwise, July surgeries were not associated with significantly different outcomes for the remaining perioperative parameters (estimated blood loss, length of stay, discharge disposition, postoperative complications), overall reoperation rates, 3-month readmission rates, and 24-month ODI, NRS back pain, NRS leg pain, EQ-5D, and NASS satisfaction score (P > 0.05, all comparisons). Conclusion. Although July surgeries were associated with longer operative times, there were no associations with other clinical outcomes compared to non-July surgeries following lumbar spondylolisthesis surgery. These findings may be due to the increased attending supervision and intraoperative education during the beginning of the academic year. There is no evidence that the influx of new trainees in July significantly affects long-term patient-centered outcomes. Level of Evidence: 3

OBJECTIVELumbar decompression without arthrodesis remains a potential treatment option for cases of low-grade spondylolisthesis (i.e., Meyerding grade I). Minimally invasive surgery (MIS) techniques have recently been increasingly used because of their touted benefits including lower operating time, blood loss, and length of stay. Herein, the authors analyzed patients enrolled in a national surgical registry and compared the baseline characteristics and postoperative clinical and patient-reported outcomes (PROs) between patients undergoing open versus MIS lumbar decompression.METHODSThe authors queried the Quality Outcomes Database for patients with grade I lumbar degenerative spondylolisthesis undergoing a surgical intervention between July 2014 and June 2016. Among more than 200 participating sites, the 12 with the highest enrollment of patients into the lumbar spine module came together to initiate a focused project to assess the impact of fusion on PROs in patients undergoing surgery for grade I lumbar spondylolisthesis. For the current study, only patients in this cohort from the 12 highest-enrolling sites who underwent a decompression alone were evaluated and classified as open or MIS (tubular decompression). Outcomes of interest included PROs at 2 years; perioperative outcomes such as blood loss and complications; and postoperative outcomes such as length of stay, discharge disposition, and reoperations.RESULTSA total of 140 patients undergoing decompression were selected, of whom 71 (50.7%) underwent MIS and 69 (49.3%) underwent an open decompression. On univariate analysis, the authors observed no significant differences between the 2 groups in terms of PROs at 2-year follow-up, including back pain, leg pain, Oswestry Disability Index score, EQ-5D score, and patient satisfaction. On multivariable analysis, compared to MIS, open decompression was associated with higher satisfaction (OR 7.5, 95% CI 2.41–23.2, p = 0.0005). Patients undergoing MIS decompression had a significantly shorter length of stay compared to the open group (0.68 days [SD 1.18] vs 1.83 days [SD 1.618], p < 0.001).CONCLUSIONSIn this multiinstitutional prospective study, the authors found comparable PROs as well as clinical outcomes at 2 years between groups of patients undergoing open or MIS decompression for low-grade spondylolisthesis.

OBJECTIVE Return to work (RTW) and satisfaction are important outcome measures after surgery for degenerative spine disease. The authors queried the prospective Quality Outcomes Database (QOD) to determine if RTW correlated with patient satisfaction. METHODS The QOD was queried for patients undergoing surgery for degenerative lumbar spondylolisthesis. The primary outcome of interest was correlation between RTW and patient satisfaction, as measured by the North American Spine Society patient satisfaction index (NASS). Secondarily, data on satisfied patients were analyzed to see what patient factors correlated with RTW. RESULTS Of 608 total patients in the QOD spondylolisthesis data set, there were 292 patients for whom data were available on both satisfaction and RTW status. Of these, 249 (85.3%) were satisfied with surgery (NASS score 1–2), and 224 (76.7%) did RTW after surgery. Of the 68 patients who did not RTW after surgery, 49 (72.1%) were still satisfied with surgery. Of the 224 patients who did RTW, 24 (10.7%) were unsatisfied with surgery (NASS score 3–4). There were significantly more people who had an NASS score of 1 in the RTW group than in the non-RTW group (71.4% vs 42.6%, p < 0.05). Failure to RTW was associated with lower level of education, worse baseline back pain (measured with a numeric rating scale), and worse baseline disability (measured with the Oswestry Disability Index [ODI]). CONCLUSIONS There are a substantial number of patients who are satisfied with surgery even though they did not RTW. Patients who were satisfied with surgery and did not RTW typically had worse preoperative back pain and ODI and typically did not have a college education. While RTW remains an important measure after surgery, physicians should be mindful that patients who do not RTW may still be satisfied with their outcome.

Abstract BACKGROUND The factors driving the best outcomes following minimally invasive surgery (MIS) for grade 1 degenerative lumbar spondylolisthesis are not clearly elucidated. OBJECTIVE To investigate the factors that drive the best 24-mo patient-reported outcomes (PRO) following MIS surgery for grade 1 degenerative lumbar spondylolisthesis. METHODS A total of 259 patients from the Quality Outcomes Database lumbar spondylolisthesis module underwent single-level surgery for degenerative grade 1 lumbar spondylolisthesis with MIS techniques (188 fusions, 72.6%). Twenty-four-month follow-up PROs were collected and included the Oswestry disability index (ODI) change (ie, 24-mo minus baseline value), numeric rating scale (NRS) back pain change, NRS leg pain change, EuroQoL-5D (EQ-5D) questionnaire change, and North American Spine Society (NASS) satisfaction questionnaire. Multivariable models were constructed to identify predictors of PRO change. RESULTS The mean age was 64.2 ± 11.5 yr and consisted of 148 (57.1%) women and 111 (42.9%) men. In multivariable analyses, employment was associated with superior postoperative ODI change (β-7.8; 95% CI [−12.9 to −2.6]; P = .003), NRS back pain change (β −1.2; 95% CI [−2.1 to −0.4]; P = .004), EQ-5D change (β 0.1; 95% CI [0.01-0.1]; P = .03), and NASS satisfaction (OR = 3.7; 95% CI [1.7-8.3]; P < .001). Increasing age was associated with superior NRS leg pain change (β −0.1; 95% CI [−0.1 to −0.01]; P = .03) and NASS satisfaction (OR = 1.05; 95% CI [1.01-1.09]; P = .02). Fusion surgeries were associated with superior ODI change (β −6.7; 95% CI [−12.7 to −0.7]; P = .03), NRS back pain change (β −1.1; 95% CI [−2.1 to −0.2]; P = .02), and NASS satisfaction (OR = 3.6; 95% CI [1.6-8.3]; P = .002). CONCLUSION Preoperative employment and surgeries, including a fusion, were predictors of superior outcomes across the domains of disease-specific disability, back pain, leg pain, quality of life, and patient satisfaction. Increasing age was predictive of superior outcomes for leg pain improvement and satisfaction.