Defining cervical spondylotic myelopathy surgical endotypes using comorbidity clustering: a Quality Outcomes Database cervical spondylotic myelopathy study.

Cervical spondylotic myelopathy (CSM) shows varying levels of improvement after surgical treatment. While some patients improve soon after surgery, others may take months to years to show any signs of improvement. The goal of this study was to evaluate postoperative improvement, patient-reported outcomes, and patient satisfaction up to 2 years after surgical treatment for CSM, which will help optimize the current treatment strategies and effectively manage patient expectations. This was a retrospective study of prospectively collected data using the Quality Outcomes Database. The primary outcomes of interest were achievement of the minimal clinically important difference (MCID) for the numeric rating scale for neck and arm pain, modified Japanese Orthopaedic Association, Neck Disability Index, and EQ-5D scores and postoperative satisfaction (North American Spine Society scale). Early and sustained improvement was defined as MCID achievement in at least one patient-reported outcome measure (PROM) at the 3-, 12-, and 24-month follow-ups. Transient improvement was defined as MCID achievement only at the 3-month and/or 12-month follow-up but not at the 24-month follow-up. Late improvement was defined as MCID achievement in at least one PROM only at the 24-month follow-up. There were 630 patients included in the comparative analysis. A total of 463 (73.5%) patients achieved early and sustained improvement, 105 (16.7%) patients experienced transient improvement with subsequent decline, 25 (4.0%) patients reported late improvement, and 37 (5.9%) patients did not report any clinically meaningful improvement after surgery. Patients with an anterior approach were more likely to be in the early and sustained improvement group. African American patients (OR 2.98, 95% CI 1.14-7.76; p = 0.03) were more likely to report late improvement when compared with White patients. The overall satisfaction rate at the 24-month follow-up was 87.8%. These findings indicate that 73.5% of patients achieve early and sustained improvement, and 87.8% of patients are satisfied with surgery 24 months postoperatively.

227. Continued improvement in functional gait and balance parameters to one year following decompression surgery for cervical spondylotic myelopathy

INTRODUCTION: Access to surgical subspeciality care is difficult to measure. Cervical spondylotic myelopathy (CSM) is a disease with high rate of progression without surgical intervention and, thus, longer symptom duration and initial symptom severity are surrogates for access to surgical care. The prospective Quality Outcomes Database (QOD) may provide insight into access to care for patients seeking surgery for CSM. METHODS: 1141 patients in the QOD with CSM underwent surgery. Access to care was measured by symptom duration (primary outcome) and baseline patient reported outcomes (PROs) including Neck Disability Index (NDI), Visual Analogue Scale-Neck Pain (VAS-NP), Visual Analogue Scale-Arm Pain (VAS-AP) and modified Japanese Orthopedic Association score (mJOA) (secondary outcomes). Multivariate logistic regression models including gender, race/ethnicity, insurance and socioeconomic status (SES) were created to predict symptom duration and baseline PROs. RESULTS: On multivariate modeling, prolonged symptom duration (>12m) was associated with Medicaid (OR 1.81, CI 1.08-3.08) and workers compensation (OR 0.39 CI 0.15-0.95). Similarly, modeling demonstrated an association between Medicaid and worse baseline NDI (β 0.37 CI 0.16-0.59), neck pain (β 0.23 CI 0.01-0.46) and mJOA (β -0.24 CI -0.47 to -0.01). Additionally, African-Americans (β 0.28 CI 0.13-0.43) were more likely to have a worse baseline NDI. Other variables associated with worse baseline PROs were SES for NDI (β -0.10 CI -0.15 to -0.04), VAS-NP (β -0.09 CI -0.14 to -0.03), VAS-AP (β -0.1 CI -0.15 to -0.04) and mJOA (β 0.08 CI 0.02-0.14) and educational level for NDI (β -0.18 CI -0.29 to -0.07), VAS-NP (β -0.26 CI -0.38 to -0.15), and VAS-AP (β -0.17 CI -0.28 to -0.05). CONCLUSIONS: For patients with CSM, disparities exist in access to care. Medicaid patients particularly suffer from prolonged symptom duration and worse baseline disease status before access to surgical care.

Recently identified prognostic variables among patients undergoing surgery for cervical spondylotic myelopathy (CSM) are limited to two large international data sets. To optimally inform shared clinical decision-making, the authors evaluated which preoperative clinical factors are significantly associated with improvement on the modified Japanese Orthopaedic Association (mJOA) scale by at least the minimum clinically important difference (MCID) 12 months after surgery, among patients from the Canadian Spine Outcomes and Research Network (CSORN). The authors performed an observational cohort study with data that were prospectively collected from CSM patients at 7 centers between 2015 and 2017. Candidate variables were tested using univariable and multiple binomial logistic regression, and multiple sensitivity analyses were performed to test assumptions about the nature of the statistical models. Validated mJOA MCIDs were implemented that varied according to baseline CSM severity. Among 205 patients with CSM, there were 64 (31%) classified as mild, 86 (42%) as moderate, and 55 (27%) as severe. Overall, 52% of patients achieved MCID and the mean change in mJOA score at 12 months after surgery was 1.7 ± 2.6 points (p < 0.01), but the subgroup of patients with mild CSM did not significantly improve (mean change 0.1 ± 1.9 points, p = 0.8). Univariate analyses failed to identify significant associations between achieving MCID and sex, BMI, living status, education, smoking, disability claims, or number of comorbidities. After adjustment for potential confounders, the odds of achieving MCID were significantly reduced with older age (OR 0.7 per decade, 95% CI 0.5-0.9, p < 0.01) and higher baseline mJOA score (OR 0.8 per point, 95% CI 0.7-0.9, p < 0.01). The effects of symptom duration (OR 1.0 per additional month, 95% CI 0.9-1.0, p = 0.2) and smoking (OR 0.4, 95% CI 0.2-1.0, p = 0.06) were not statistically significant. Surgery is effective at halting the progression of functional decline with CSM, and approximately half of all patients achieve the MCID. Data from the CSORN confirmed that older age is independently associated with poorer outcomes, but novel findings include that patients with milder CSM did not experience meaningful improvement, and that symptom duration and smoking were not important. These findings support a nuanced approach to shared decision-making that acknowledges some prognostic uncertainty when weighing the various risks, benefits, and alternatives to surgical treatment.

Workers' compensation (WC) status tends to negatively affect patient outcomes in spine surgery. This study aims to evaluate the potential effect of WC status on patient-reported outcomes (PROs) after cervical disc arthroplasty (CDR) at an ambulatory surgical center (ASC). A single-surgeon registry was retrospectively reviewed for patients who had undergone elective CDR at an ASC. Patients with missing insurance data were excluded. Propensity score-matched cohorts were generated by the presence or lack of WC status. PROs were collected preoperatively and at 6-week, 12-week, 6-month, and 1-year time points. PROs included the Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), visual analog scale (VAS) neck and arm pain, and Neck Disability Index. PROs were compared within and between groups. Minimum clinically important difference (MCID) achievement rates were compared between groups. Sixty-three patients were included, with 36 without WC (non-WC) and 27 with WC. The non-WC cohort demonstrated postoperative improvement in all PROs at all time points, with the exception of VAS arm past the 12-week point ( P ≤ 0.030, all). The WC cohort demonstrated postoperative improvement in VAS neck at 12-week, 6-month, and 1-year time points ( P ≤ 0.025, all). The WC cohort improved in VAS arm and Neck Disability Index at the 12-week and 1-year points as well ( P ≤ 0.029, all). The non-WC cohort reported superior PRO scores in every PRO at one or more postoperative time points ( P ≤ 0.046, all). The non-WC cohort demonstrated higher rates of minimum clinically important difference achievement in PROMIS-PF at 12 weeks ( P ≤ 0.024). Patients with WC status undergoing CDR at an ASC may report inferior pain, function, and disability outcomes compared with those with private or government-provided insurance. Perceived inferior disability in WC patients persisted into the long-term follow-up period (1 year). These findings may aid surgeons in setting realistic preoperative expectations with patients at risk of inferior outcomes.

Friday, September 28, 2018 10:30 AM–12:00 PM abstracts: complications of cervical spine surgery: 157. Risk factors associated with failure to reach minimum clinically important difference in patient-reported outcomes after anterior cervical discectomy and fusion

Retrospective cohort. The aim was to determine how neck pain and disability improve following anterior cervical discectomy and fusion among patients with myeloradiculopathy. Neck pain and disability have traditionally been assessed using the neck disability index (NDI) and visual analog scale (VAS). Few studies have investigated how neck pain/disability improve differently among patients with symptoms of both myelopathy and radiculopathy. Patients were identified through retrospective review of a prospective surgical database from 2013 to 2020. Patient-reported outcome measures (PROMs) collected included VAS neck and arm, NDI, 12-Item Short Form physical composite score (SF-12 PCS), Patient-Reported Outcomes Measurement Information System physical function (PROMIS PF), and Patient Health Questionnaire 9 (PHQ-9). PROMs were collected preoperatively and up to 1-year postoperatively. Patients were categorized by preoperative symptom severity: high VAS arm (>7); high NDI (>55); high VAS arm and NDI; and moderate symptoms. Linear and logistic regression evaluated the impact of preoperative symptom severity on PROM scores and achievement of minimum clinically important difference (MCID), respectively. A total of 187 patients were included, 98 with neither high VAS arm nor NDI (moderate group), 14 with high NDI, 46 with high VAS arm, and 29 with high NDI and VAS arm. Postoperatively, greater symptom severity was a significant predictor of VAS neck (all timepoints; P ≤0.002, all), VAS arm (6 weeks; P =0.007), NDI (6 weeks to 6 months; P <0.001, all), SF-12 PCS (6 months; P =0.004), P ROMIS PF (6 weeks; P =0.007), and PHQ-9 (6 weeks to 6 months; P <0.001, all). Mean postoperative improvement was different among the four severity groups for VAS arm, NDI, and VAS neck (except for 1-year) ( P ≤0.002, all). Overall MCID achievement rates were significantly greater among higher symptom severity groups across VAS arm and NDI ( P ≤0.003, both). PROM improvement and MCID achievement for NDI, VAS neck, and VAS arm differed based on symptom severity.

50. Sagittal parameters poorly predict clinical outcomes following anterior cervical discectomy and fusion

50. Re-emergence of depressive symptoms and associated risk factors in cervical spine patients

Treatment effectiveness following spine surgery is usually gauged with the help of patient-reported outcome (PRO) questionnaires. Although these questionnaires assess pain, disability, and general health state, their numerical scores lack direct, clinically significant meaning. Thus, the concept of minimum clinically important difference (MCID) has been introduced, which indicates the smallest change in an outcome measure that reflects clinically meaningful improvement to patients. The authors set out to determine anterior cervical discectomy and fusion (ACDF)-specific MCID values for the visual analog scale (VAS), Neck Disability Index (NDI), 12-Item Short-Form Health Survey (SF-12), and EQ-5D (the EuroQol health survey) in patients undergoing ACDF for cervical radiculopathy. Data on 69 patients who underwent ACDF for cervical radiculopathy were collected in the authors' web-based, prospective registry during the study enrollment period. Patient-reported outcome questionnaires (VAS-neck pain [NP]), VAS-arm pain [AP], NDI, SF-12, and EQ-5D) were administered preoperatively and 3 months postoperatively, allowing 3-month change scores to be calculated. Four established calculation methods were used to calculate anchor-based MCID values using the North American Spine Society (NASS) patient satisfaction scale as the anchor: 1) average change, 2) minimum detectable change (MDC), 3) change difference, and 4) receiver operating characteristic (ROC) curve analysis. Sixty-one patients (88%) were available at follow-up. At 3 months postoperatively, statistically significant improvement (p < 0.001) was observed for the following PROs assessed: VAS-NP (2.7 ± 3.3), VAS-AP (3.7 ± 3.6), NDI (23.2% ± 19.7%), SF-12 physical component score (PCS; 10.7 ± 9.7), and EQ-5D (0.20 ± 0.23 QALY). Improvement on the SF-12 mental component score (MCS) trended toward significance (3.4 ± 11.4, p = 0.07). The 4 MCID calculation methods generated a range of MCID values for each of the PROs: VAS-NP 2.6-4.0, VAS-AP 2.4-4.2, NDI 16.0%-27.6%, SF-12 PCS 7.0-12.2, SF-12 MCS 0.0-7.2, and EQ-5D 0.05-0.24 QALY. The maximum area under the curve (AUC) was observed for NDI (0.80), and the minimum AUC was observed for SF-12 MCS (0.66) and EQ-5D (0.67). Based on the MDC approach, the MCID threshold was 2.6 points for VAS-NP, 4.1 points for VAS-AP, 17.3% for NDI, 8.1 points for SF-12 PCS, 4.7 points for SF-12 MCS, and 0.24 QALY for EQ-5D. The mean improvement in patient scores at 3 months surpassed the MCID threshold for VAS-NP, NDI, and SF-12 PCS but not for VAS-AP, SF-12 MCS, and EQ-5D. The ACDF-specific MCID is highly variable depending on the calculation technique used. The MDC approach seems to be most appropriate for MCID calculations in the ACDF population, as it provided a threshold value above the 95% confidence interval of nonresponders (greater than the measurement error) and was closest to the average change of most PROs reported by responders. When the MDC method was applied with the NASS patient satisfaction scale as the anchor, the MCID thresholds were 2.6 points for VAS-NP, 4.1 points for VAS-AP, 17.3% for NDI, 8.1 points for SF-12 PCS, 4.7 points for SF-12 MCS, and 0.24 QALY for EQ-5D.

This is a prospective cohort study. To evaluate the effect of cervical decompression surgery on the biomechanics of the spine and lower extremities in cervical spondylotic myelopathy (CSM) patients and compare with asymptomatic controls. Difficulties with balance and gait are one of the most common manifestations of CSM. Patients with CSM have a slower gait speed, prolonged double support duration, and reduced cadence compared with healthy controls. Surgical decompression was found to improve clinical outcomes, but conflicting results are noted when examining function. In total, 25 subjects with symptomatic CSM underwent clinical gait analysis performed a week before (pre) and 3 months after the surgery (post). Clinical gait analysis was performed on 30 matched asymptomatic controls as well. Spine and lower extremity kinematics, spatiotemporal parameters, and clinical outcome were measured. CSM patients demonstrated slower walking speed (P=0.006), reduced cadence (P=0.001), longer step time (P=0.013) wider step width (P=0.001), greater ankle range of motion (ROM) (P=0.019), less hip ROM (P=0.050), increased pelvis (P=0.001), and lumbar spine (P=0.049) ROM compared with controls. Postoperatively CSM patients demonstrated a faster walking speed (P=0.002), increased cadence (P=0.029), longer step length (P=0.015), narrower step width (P=0.004), greater knee (P=0.043), and hip ROM (P=0.007), less pelvis (P=0.002), lumbar spine (P=0.035), and cervical spine (P=0.044) ROM, and improved clinical outcomes (neck pain disability index questionnaire, oswestry disability index, and visual analog scale; P=0.001) compared with their preoperative values. Postsurgical CSM patients did not present with any differences compared with controls, beside pelvis ROM (P=0.019). Preoperatively, CSM patients clearly showed altered gait parameters compared with controls. However, after cervical decompression surgery, CSM patients exhibited improved gait pattern, spatiotemporal parameters, spine and lower extremity ROM, as well as patient-reported outcomes. Postoperatively, CSM patients did not show major differences in gait when compared with matched asymptomatic controls.

BackgroundThe aim of this study was to determine the incidence of coexisting symptomatic lumbar canal stenosis (LCS) in patients after surgery for cervical spondylotic myelopathy (CSM) and identify possible predictive factors associated with it.Materials and methodsWe retrospectively reviewed patients with CSM at our institution between January 2005 and December 2015. Clinical and radiographic factors including age, gender, body mass index, Japanese Orthopedic Association scores, cervical alignment, anteroposterior diameter of cervical canal, number of levels with CSM, and percentage of cervical cord compression were investigated. Symptomatic LCS was defined as leg symptoms and a narrowing of the lumbar spinal canal at one level at least, which is confirmed by magnetic resonance images of the lumbar spine. Univariate and multivariate analyses were used to identify possible predictive factors. Pearson correlation analysis was also conducted to analyze the association between cervical parameters and percentage of LCS.ResultsA total of 317 patients with CSM met the criteria for inclusion. There were 39 patients (12.3%) with LCS after cervical surgery during a mean of 7.3 years’ follow-up. In the multivariate logistic regression analysis, narrow diameter of cervical canal (OR, 3.96; 95% CI, 1.20–13.04) was identified as the only independent predictor of symptomatic LCS in CSM patients. The correlation coefficient between anteroposterior diameter of cervical canal and severity of LCS indicated a significantly positive linear relationship with 0.536 (P<0.001).ConclusionWe found that narrow diameter of cervical canal was associated with symptomatic LCS in CSM patients. Patients with this risk factor should be informed the possibility of symptomatic LCS.

For laminectomy and posterior spinal fusion (LPSF) surgery for cervical spondylotic myelopathy (CSM), the evidence is unclear as to whether fusions should cross the cervicothoracic junction (CTJ). To compare LPSF outcomes between those with and without lower instrumented vertebrae (LIV) crossing the CTJ. A consecutive series of adults undergoing LPSF for CSM from 2012 to 2018 with a minimum of 12-mo follow-up were identified. LPSF with subaxial upper instrumented vertebrae and LIV between C6 and T2 were included. Clinical and radiographic outcomes were compared. A total of 79 patients were included: 46 crossed the CTJ (crossed-CTJ) and 33 did not. The mean follow-up was 22.2 mo (minimum: 12 mo). Crossed-CTJ had higher preoperative C2-7 sagittal vertical axis (cSVA) (33.3±16.0vs 23.8±12.4mm, P=.01) but similar preoperative cervical lordosis (CL) and CL minus T1-slope (CL minus T1-slope) (P > .05, both comparisons). The overall reoperation rate was 3.8% (crossed-CTJ: 2.2%vs not-crossed: 6.1%, P=.37). In adjusted analyses, crossed-CTJ was associated with superior cSVA (β = -9.7; P=.002), CL (β = 6.2; P=.04), and CL minus T1-slope (β = -6.6; P=.04), but longer operative times (β = 46.3; P=.001). Crossed- and not-crossed CTJ achieved similar postoperative patient-reported outcomes [Visual Analog Scale (VAS) neck pain, VAS arm pain, Nurick Grade, Modified Japanese Orthopedic Association Scale, Neck Disability Index, and EuroQol-5D] in adjusted multivariable analyses (adjusted P>.05). For the entire cohort, higher postoperative CL was associated with lower postoperative arm pain (adjusted Pearson's r -0.1, P=.02). No postoperative cervical radiographic parameters were associated with neck pain (P>.05). Subaxial LPSF for CSM that crossed the CTJ were associated with superior radiographic outcomes for cSVA, CL, and CL minus T1-slope, but longer operative times. There were no differences in neck pain or reoperation rate.

Improved Sagittal Alignment Is Associated with Early Postoperative Neck Disability and Pain-Related Patient-Reported Outcomes Following Posterior Cervical Decompression and Fusion for Myelopathy

Characterizing post-operative ICU admission after cervical spondylotic myelopathy surgery.