Contemporary trends in the incidence and timing of spinal metastases: A population-based study.

Background: Spinal metastases are a significant complication of advanced cancer. In this study, we assess temporal trends in the incidence and timing of spinal metastases and examine underlying patient demographics and primary cancer associations. Methods: In this population-based retrospective cohort study, health data from 2007 to 2019 in Ontario, Canada were analyzed (n = 37, 375 patients identified with spine metastases). Primary outcomes were annual incidence of spinal metastasis, and time to metastasis after primary diagnosis. Results: The age-standardized incidence of spinal metastases increased from 229 to 302 cases per million over the 13-year study period. The average annual percent change (AAPC) in incidence was 2.2% (95% CI: 1.4% to 3.0%) with patients aged ≥85 years demonstrating the largest increase (AAPC 5.2%; 95% CI: 2.3% to 8.3%). Lung cancer had the greatest annual incidence, while prostate cancer had the greatest increase in annual incidence (AAPC 6.5; 95% CI: 4.1% to 9.0%). Lung cancer patients were found to have the highest risk of spine metastasis with 10.3% (95% CI: 10.1% to 10.5%) of patients being diagnosed at 10 years. Gastrointestinal cancer patients were found to have the lowest risk of spine metastasis with 1.0% (95% CI: 0.9% to 1.0%) of patients being diagnosed at 10 years. Conclusions: The incidence of spinal metastases has increased in recent years, particularly among older patients. The incidence and timing vary substantially among different primary cancer types. These findings contribute to the understanding of disease trends and emphasize a growing population of patients who require subspecialty care.

Treatment of Acute Traumatic Central Cord Syndrome: A Study of North American Trauma Centers.

BACKGROUND AND OBJECTIVES: Central cord syndrome (CCS) is expected to become the most common traumatic spinal cord injury, yet its optimal management remains unclear. This study aimed to evaluate variability in nonoperative vs operative treatment for CCS between trauma centers in the American College of Surgeons Trauma Quality Improvement Program, identify patient- and hospital-level factors associated with treatment, and determine the association of treatment with outcomes. METHODS: Adults with CCS were identified from the Trauma Quality Improvement Program database (2014-2016). Mixed-effects modeling with a random intercept for trauma centers was used to examine the adjusted association of patient- and hospital-level variables with nonoperative treatment. The random-effects output of the model assessed the risk-adjusted variability in nonoperative treatment across centers. Outlier hospitals were identified, and the median odds ratio was calculated. The adjusted effect of nonoperative treatment on mortality, morbidity, and hospital length of stay (LOS) was examined at the patient and hospital level by mixed-effects regression. RESULTS: Three thousand, nine hundred twenty-eight patients across 255 centers were eligible; of these, 1523 (38.8%) were treated nonoperatively. Older age, noncommercial insurance (odds ratio [OR] 1.26, 95% CI 1.08-1.48, P = .004), absence of fracture (OR 0.58, 95% CI 0.49-0.68, P < .001), severe head injury (OR 1.41, 95% CI 1.09-1.82, P = .008), and comatose presentation (1.82, 95% CI 1.15-2.89, P = .011) were associated with nonoperative treatment. Twenty-eight hospitals were outliers, and the median odds ratio was 2.02. Patients receiving nonoperative treatment had shorter LOS (mean difference -4.65 days). Nonoperative treatment was associated with lesser in-hospital morbidity (OR 0.49, 95% CI 0.37-0.63, P < .001) at the patient level. There was no difference in mortality. CONCLUSION: Operative decision-making for CCS is influenced by patient factors. There remains substantial variability between trauma centers not explained by case-mix differences. Nonoperative treatment was associated with shorter hospital LOS and lesser inpatient morbidity.

Adverse effects of frailty on the outcomes of surgery for degenerative cervical myelopathy: results from a prospective multicenter international data set of 757 patients.

OBJECTIVE: The goal of this study was to determine the effect of the degree of frailty on long-term neurological and functional outcomes after surgery for degenerative cervical myelopathy (DCM). METHODS: A combined database of patients enrolled in the Cervical Spondylotic Myelopathy-North America and Cervical Spondylotic Myelopathy-International prospective international multicenter observational studies who underwent surgery for DCM was used as the source data. All patients underwent baseline and follow-up assessment at 2 years after surgery for functional, disability, and quality of life measurements (modified Japanese Orthopaedic Association [mJOA] scale, Neck Disability Index, SF-36 physical and mental component summary scores). Patients were separated into 4 groups according to their baseline modified frailty index 5-point scale score: not frail, pre-frail, frail, and severely frail. Differences among groups were analyzed at baseline and at 2 years after surgery, including change in scores (delta values) and the odds ratio of achieving the minimum clinically important difference (MCID) through univariate and multivariable logistic regression adjusting for age, approach, number of levels treated, and sex. RESULTS: A total of 757 patients (63% male) with a mean age of 56 (95% CI 55.5-57.2) years were included: 470 patients underwent an anterior approach, 310 had a posterior approach, and 23 had a combined anterior/posterior approach. A total of 50% (n = 378) of patients were classified as not frail, with 33% (n = 250) pre-frail, 13% (n = 101) frail, and 4% (n = 28) severely frail. The baseline mJOA score was significantly lower with increasing frailty (14.00 [95% CI 13.75-14.19] for not frail vs 9.71 [95% CI 9.01-10.42] for severely frail patients; p < 0.05), but the change at 2 years was not significantly different among all groups (2.43 [95% CI 2.16-2.71] for not frail vs 2.56 [95% CI 1.10-4.02] for severely frail). The SF-36 delta values were also not different among groups, but significantly worse at baseline with increasing frailty. The odds ratio of achieving MCID for mJOA was significantly higher in the not frail group (1.89 [95% CI 1.36-2.61]; p < 0.05) compared to the other frailty cohorts, which remained after adjusting for age, approach, levels treated, and sex. The odds ratio of achieving MCID for the SF-36 domains was similar among all frailty groups. CONCLUSIONS: Increasing frailty is associated with worse baseline functional and quality of life measures in patients undergoing surgery for DCM. Frailty does not affect the magnitude of improvement in outcome measures after surgery, but reduces the chance of achieving the MCID for functional impairment significantly. Preoperative frailty assessment can therefore help guide clinicians in managing expectations after surgery for DCM. Potentially modifiable factors should be optimized in frail patients preoperatively to enhance functional outcomes.

Prevalence of Neck Pain in Patients with Degenerative Cervical Myelopathy and Short-Term Response After Operative Treatment: A Cohort Study of 664 Patients From 26 Global Sites.

STUDY DESIGN: Ambispective cohort study. OBJECTIVES: 1) To define the prevalence of neck pain in patients with degenerative cervical myelopathy (DCM). 2) To identify associated factors of preoperative neck pain in patients with DCM. 3) To assess the neck pain response to surgical intervention. METHODS: 757 patients with DCM were enrolled at 26 global sites from 2005 to 2011. A total of 664 patients had complete neck pain scores preoperatively (Neck Disability Index, NDI). The prevalence and severity of neck pain preoperatively and at the 6-months follow-up was summarized. Functional assessments of individuals with and without pain were compared. Associations of preoperative neck pain and related factors were evaluated. RESULTS: Preoperatively, 79.2% of patients reported neck pain while 20.8% had no neck pain. Of individuals with neck pain, 20.2% rated their pain as very mild, 27.9% as moderate, 19.6% as fairly severe, 9.6% as very severe and 1.9% as the worst imaginable. Functional status (mJOA), number of stenotic levels, age, and duration of symptoms did not significantly differ in patients with and without pain. Factors associated with the presence of neck pain were female gender, BMI ≥27 kg/m2, rheumatologic and gastrointestinal comorbidities, and age <57 years. Neck pain improved significantly from the preoperative examination to the 6-months postoperative follow-up (P < .0001). CONCLUSION: Here, we demonstrate a high prevalence of neck pain in patients with DCM as well as a link between gender, body weight, comorbidity and age. We highlight a significant reduction in neck pain 6 months after surgery.

Early vs Late Surgical Decompression for Central Cord Syndrome.

Importance: The optimal clinical management of central cord syndrome (CCS) remains unclear; yet this is becoming an increasingly relevant public health problem in the face of an aging population. Objective: To provide a head-to-head comparison of the neurologic and functional outcomes of early (<24 hours) vs late (≥24 hours) surgical decompression for CCS. Design, Setting, and Participants: Patients who underwent surgery for CCS (lower extremity motor score [LEMS] - upper extremity motor score [UEMS] ≥ 5) were included in this propensity score-matched cohort study. Data were collected from December 1991 to March 2017, and the analysis was performed from March 2020 to January 2021. This study identified patients with CCS from 3 international multicenter studies with data on the timing of surgical decompression in spinal cord injury. Participants were included if they had a documented baseline neurologic examination performed within 14 days of injury. Participants were eligible if they underwent surgical decompression for CCS. Exposures: Early surgery was compared with late surgery. Main Outcomes and Measures: Propensity scores were calculated as the probability of undergoing early compared with late surgery using the logit method and adjusting for relevant confounders. Propensity score matching was performed in a 1:1 ratio by an optimal-matching technique. The primary end point was motor recovery (UEMS, LEMS, American Spinal Injury Association [ASIA] motor score [AMS]) at 1 year. Secondary end points were Functional Independence Measure (FIM) motor score and complete independence in each FIM motor domain at 1 year. Results: The final study cohort consisted of 186 patients with CCS. The early-surgery group included 93 patients (mean [SD] age, 47.8 [16.8] years; 66 male [71.0%]), and the late-surgery group included 93 patients (mean [SD] age, 48.0 [15.5] years; 75 male [80.6%]). Early surgical decompression resulted in significantly improved recovery in upper limb (mean difference [MD], 2.3; 95% CI, 0-4.5; P = .047), but not lower limb (MD, 1.1; 95% CI, -0.8 to 3.0; P = .30), motor function. In an a priori-planned subgroup analysis, outcomes were comparable with early or late decompressive surgery in patients with ASIA Impairment Scale (AIS) grade D injury. However, in patients with AIS grade C injury, early surgery resulted in significantly greater recovery in overall motor score (MD, 9.5; 95% CI, 0.5-18.4; P = .04), owing to gains in both upper and lower limb motor function. Conclusions and Relevance: This cohort study found early surgical decompression to be associated with improved recovery in upper limb motor function at 1 year in patients with CCS. Treatment paradigms for CCS should be redefined to encompass early surgical decompression as a neuroprotective therapy.

A Novel Method to Classify Cervical Incomplete Spinal Cord Injury Based on Potential for Recovery: A Group-Based Trajectory Analysis.

The outcomes of cervical incomplete spinal cord injury (SCI) are heterogeneous. This study sought to dissociate subgroups of cervical incomplete SCI patients with distinct longitudinal temporal profiles of recovery in upper limb motor function. Patients with cervical incomplete SCI (American Spinal Injury Association Impairment Scale [AIS] B-D; C1-C8) were identified from four prospective, multi-center SCI datasets. A group-based trajectory model was fit to longitudinal upper extremity motor scores out to 1 year. Multi-variable multinomial logistic regression was performed to identify features that characterize each trajectory group. A classification system for predicting trajectory group at baseline was developed by recursive partitioning. In total, 801 patients were eligible. Four distinct trajectory groups were identified: 1) "Poor outcome": Severe injury, very minimal recovery; 2) "Moderate recovery": Moderate-to-severe injury, moderate recovery; most recovery occurs by 6 months, with mild, gradual recovery continuing thereafter; 3) "Good recovery": Moderate injury, good recovery; most recovery occurs by 3 months, with mild, gradual recovery continuing thereafter; and 4) "Excellent outcome": Mild injury, recovery to normal/near-normal by 3 months. On adjusted analyses, older age was associated with lower likelihood of "excellent outcome" (p = 0.020). AIS C and D injuries were associated with "moderate recovery," "good recovery," and "excellent outcome" (p < 0.001). Mid-cervical injuries occurred more frequently in "moderate recovery," "good recovery," and "excellent outcome" (p < 0.001) groups. Early surgical decompression (< 24 h) was associated with increased propensity for "good recovery" (p = 0.039) and "excellent outcome" (p = 0.048). A classification model based on recursive partitioning could predict trajectory group using age, AIS grade, and neurological level with an area under the curve of 0.81. Patients with cervical incomplete SCI demonstrate distinct temporal profiles of recovery in upper limb motor function. The trajectory a patient is likely to follow may be predicted at baseline with fair accuracy.

Earlier Surgery Reduces Complications in Acute Traumatic Thoracolumbar Spinal Cord Injury: Analysis of a Multi-Center Cohort of 4108 Patients.

Early surgical intervention to decompress the spinal cord and stabilize the spinal column in patients with acute traumatic thoracolumbar spinal cord injury (TLSCI) may lessen the risk of developing complications and improve outcomes. However, there has yet to be agreement on what constitutes "early" surgery; reported thresholds range from 8 to 72 h. To address this knowledge gap, we conducted an observational cohort study using data from the American College of Surgeons (ACS) Trauma Quality Improvement Program (TQIP) from 2010 to 2016. The association between time from hospital arrival to surgical intervention and risk of major complications was assessed using restricted cubic splines. Propensity score matching was then used to assess the association between delayed surgery and risk of complications. Across 354 trauma centers 4108 adult TLSCI patients who underwent surgery were included. Median time-to-surgery was 18.8 h (interquartile range [IQR]: 7.4-40.9 h). The spline model suggests the risk of major complication rises consistently after a 12-h surgical wait-time. After propensity score matching, the odds of major complication were significantly lower for those receiving surgery within 12 h (odds ratio [OR] 0.77, 95% confidence interval [CI]: 0.64 to 0.94). This was also true for immobility-related complications (OR 0.79, 95% CI: 0.64 to 0.97). Patients in the early group spent 1.5 fewer days in the critical care unit on average (95% CI: -2.09 to -0.88). Although surgery within 12 h may not always be feasible, these data suggest that whenever possible surgeons should strive to reduce the amount of time between hospital arrival and surgical intervention, and health care systems should support this endeavor.

Spinal Cord Signal Change on Magnetic Resonance Imaging May Predict Worse Clinical In- and Outpatient Outcomes in Patients with Spinal Cord Injury: A Prospective Multicenter Study in 459 Patients.

Prognostic factors for clinical outcome after spinal cord (SC) injury (SCI) are limited but important in patient management and education. There is a lack of evidence regarding magnetic resonance imaging (MRI) and clinical outcomes in SCI patients. Therefore, we aimed to investigate whether baseline MRI features predicted the clinical course of the disease. This study is an ancillary to the prospective North American Clinical Trials Network (NACTN) registry. Patients were enrolled from 2005-2017. MRI within 72 h of injury and a minimum follow-up of one year were available for 459 patients. Patients with American Spinal Injury Association impairment scale (AIS) E were excluded. Patients were grouped into those with (n = 354) versus without (n = 105) SC signal change on MRI T2-weighted images. Logistic regression analysis adjusted for commonly known a priori confounders (age and baseline AIS). Main outcomes and measures: The primary outcome was any adverse event. Secondary outcomes were AIS at the baseline and final follow-up, length of hospital stay (LOS), and mortality. A regression model adjusted for age and baseline AIS. Patients with intrinsic SC signal change were younger (46.0 (interquartile range (IQR) 29.0 vs. 50.0 (IQR 20.5) years, p = 0.039). There were no significant differences in the other baseline variables, gender, body mass index, comorbidities, and injury location. There were more adverse events in patients with SC signal change (230 (65.0%) vs. 47 (44.8%), p < 0.001; odds ratio (OR) = 2.09 (95% confidence interval (CI) 1.31-3.35), p = 0.002). The most common adverse event was cardiopulmonary (186 (40.5%)). Patients were less likely to be in the AIS D category with SC signal change at baseline (OR = 0.45 (95% CI 0.28-0.72), p = 0.001) and in the AIS D or E category at the final follow-up (OR = 0.36 (95% CI 0.16-0.82), p = 0.015). The length of stay was longer in patients with SC signal change (13.0 (IQR 17.0) vs. 11.0 (IQR 14.0), p = 0.049). There was no difference between the groups in mortality (11 (3.2%) vs. 4 (3.9%)). MRI SC signal change may predict adverse events and overall LOS in the SCI population. If present, patients are more likely to have a worse baseline clinical presentation (i.e., AIS) and in- or outpatient clinical outcome after one year. Patients with SC signal change may benefit from earlier, more aggressive treatment strategies and need to be educated about an unfavorable prognosis.

Reality of Accomplishing Surgery within 24 Hours for Complete Cervical Spinal Cord Injury: Clinical Practices and Safety.

Substantial clinical data support an association between superior neurological outcomes and early (within 24 h) surgical decompression for those with traumatic cervical spinal cord injury (SCI). Despite this, much discussion persists around feasibility and safety of this time threshold, particularly for those with a complete cervical SCI. This study aims to assess clinical practices and the safety profile of early surgery across a large sample of North American trauma centers. Data were derived from the Trauma Quality Improvement Program database from 2010-2016. Adult patients with a complete cervical SCI (American Spinal Injury Association [ASIA] A) who underwent surgery were included. Patients were stratified into those receiving surgery at or before 24 h and those receiving delayed intervention. Risk-adjusted variability in surgical timing across trauma centers was investigated using mixed-effects regression. In-hospital adverse events including death, major complications, and immobility-related complications were compared between groups after propensity score matching. There were 2862 patients from 353 North American trauma centers included; 1760 (61.5%) underwent surgery within 24 h. Case-mix and hospital-level characteristics explained only 6% of the variability in surgical timing both between centers and within centers. No significant differences in adverse events were identified between groups. These findings suggest a relatively large proportion of patients are not receiving surgery within the recommended time frame, despite apparent safety. Moreover, patient and hospital-level characteristics explain little of the variability in time-to-surgery. Further knowledge translation is needed to increase the proportion of patients in whom surgery is performed before the 24-h threshold so patients might reach their greatest potential for neurological recovery.

Variability in time to surgery for patients with acute thoracolumbar spinal cord injuries.

There are limited data pertaining to current practices in timing of surgical decompression for acute thoracolumbar spinal cord injury (SCI). We conducted a retrospective cohort study to evaluate variability in timing between- and within-trauma centers in North America; and to identify patient- and hospital-level factors associated with treatment delay. Adults with acute thoracolumbar SCI who underwent decompressive surgery within five days of injury at participating trauma centers in the American College of Surgeons Trauma Quality Improvement Program were included. Mixed-effects regression with a random intercept for trauma center was used to model the outcome of time to surgical decompression and assess risk-adjusted variability in surgery timeliness across centers. 3,948 patients admitted to 214 TQIP centers were eligible. 28 centers were outliers, with a significantly shorter or longer time to surgery than average. Case-mix and hospital characteristics explained < 1% of between-hospital variability in surgical timing. Moreover, only 7% of surgical timing variability within-centers was explained by case-mix characteristics. The adjusted intraclass correlation coefficient of 12% suggested poor correlation of surgical timing for patients with similar characteristics treated at the same center. These findings support the need for further research into the optimal timing of surgical intervention for thoracolumbar SCI.

A deep learning model for detection of cervical spinal cord compression in MRI scans.

Magnetic Resonance Imaging (MRI) evidence of spinal cord compression plays a central role in the diagnosis of degenerative cervical myelopathy (DCM). There is growing recognition that deep learning models may assist in addressing the increasing volume of medical imaging data and provide initial interpretation of images gathered in a primary-care setting. We aimed to develop and validate a deep learning model for detection of cervical spinal cord compression in MRI scans. Patients undergoing surgery for DCM as a part of the AO Spine CSM-NA or CSM-I prospective cohort studies were included in our study. Patients were divided into a training/validation or holdout dataset. Images were labelled by two specialist physicians. We trained a deep convolutional neural network using images from the training/validation dataset and assessed model performance on the holdout dataset. The training/validation cohort included 201 patients with 6588 images and the holdout dataset included 88 patients with 2991 images. On the holdout dataset the deep learning model achieved an overall AUC of 0.94, sensitivity of 0.88, specificity of 0.89, and f1-score of 0.82. This model could improve the efficiency and objectivity of the interpretation of cervical spine MRI scans.

Clinical outcomes of nonoperatively managed degenerative cervical myelopathy: an ambispective longitudinal cohort study in 117 patients.

OBJECTIVE: Degenerative cervical myelopathy (DCM) is among the most common pathologies affecting the spinal cord but its natural history is poorly characterized. The purpose of this study was to investigate functional outcomes in patients with DCM who were managed nonoperatively as well as the utility of quantitative clinical measures and MRI to detect deterioration. METHODS: Patients with newly diagnosed DCM or recurrent myelopathic symptoms after previous surgery who were initially managed nonoperatively were included. Retrospective chart reviews were performed to analyze clinical outcomes and anatomical MRI scans for worsening compression or increased signal change. Quantitative neurological assessments were collected prospectively, including modified Japanese Orthopaedic Association (mJOA) score; Quick-DASH; graded redefined assessment of strength, sensation, and prehension-myelopathy version (GRASSP-M: motor, sensory, and dexterity); grip dynamometer; Berg balance scale score; gait stability ratio; and gait variability index. A deterioration of 10% was considered significant (e.g., a 2-point decrease in mJOA score). RESULTS: A total of 117 patients were included (95 newly diagnosed, 22 recurrent myelopathy), including 74 mild, 28 moderate, and 15 severe cases. Over a mean follow-up of 2.5 years, 57% (95% CI 46%-67%) of newly diagnosed patients and 73% (95% CI 50%-88%) of patients with recurrent DCM deteriorated neurologically. Deterioration was best detected with grip strength (60%), GRASSP dexterity (60%), and gait stability ratio (50%), whereas the mJOA score had low sensitivity (33%) in 50 patients. A composite score had a sensitivity of 81% and a specificity of 82%. The sensitivity of anatomical MRI was 28% (83 patients). CONCLUSIONS: DCM appears to have a poor natural history; however, prospective studies are needed for validation. Serial assessments should include mJOA score, grip strength, dexterity, balance, and gait analysis. The absence of worsening on anatomical MRI or in mJOA scores is not sufficient to determine clinical stability.

Frailty adversely affects outcomes of patients undergoing spine surgery: a systematic review.

BACKGROUND: With an aging population, there are an increasing number of elderly patients undergoing spine surgery. Recent literature in other surgical specialties suggest frailty to be an important predictor of outcomes. PURPOSE: The aim of this review was to examine the association between frailty and outcomes after spine surgery. STUDY DESIGN: A systematic review was performed. PATIENT SAMPLE: Electronic databases from 1946 to 2020 were searched to identify articles on frailty and spine surgery. OUTCOME MEASURES: The primary outcome was adverse events. Secondary outcomes included other measures of morbidity, mortality, and patient outcomes. METHODS: Sample size, mean age, age limitation, data source, study design, primary pathology, surgical procedure performed, follow-up period, assessment of frailty used, surgical outcomes, and impact of frailty on outcomes were extracted from eligible studies. Quality and bias were assessed using the PRISMA 27-point item checklist and the QUADAS-2 tool. RESULTS: Thirty-two studies were selected for review, with a total of 127,813 patients. There were eight different frailty indices/measures. Regardless of how frailty was measured, frailty was associated with an increased risk of adverse events, mortality, extended length of stay, readmission, and nonhome discharge. CONCLUSION: There is strong evidence that frailty is associated with an increased risk of morbidity and mortality in patients who received spine surgery. However, it remains inconclusive whether frailty impacts patient outcomes and quality of life after surgery.

Inter-rater Reliability of the Modified Japanese Orthopedic Association Score in Degenerative Cervical Myelopathy: A Cross-sectional Study.

STUDY DESIGN: Prospective cross-sectional blinded-assessor cohort study. OBJECTIVE: The aim of this study was to determine the inter-rater reliability of the modified Japanese Orthopaedic Association (mJOA) score in a large cohort of degenerative cervical myelopathy (DCM) patients. SUMMARY OF BACKGROUND DATA: The mJOA score is widely accepted as the primary outcome measure in DCM; it has been utilized in clinical practice guidelines and directly influences treatment recommendations, but its reliability has not been established. METHODS: A refined version of the mJOA was administered to DCM patients by two or more blinded clinicians. Inter-rater reliability was measured using intraclass correlation coefficient (ICC), agreement, and mean difference for mJOA total score and subscores. Data were also analyzed with analysis of variance for differences by mJOA severity (mild: 15-17, moderate: 12-14, severe: <12), assessor, assessment order, previous surgery, age, and sex. RESULTS: One hundred fifty-four DCM patients underwent 322 mJOA assessments (183 paired assessments). ICC was 0.88 for total mJOA, 0.79 for upper extremity (UE) motor, 0.84 for lower extremity (LE) motor, 0.63 for UE sensation, and 0.78 for urinary function subscores. Paired assessments were identical across all four subscores in 25%. The mean difference in mJOA was 0.93 points between assessors, and this differed by severity (mild: 0.68, moderate: 1.24, severe: 0.87, P = 0.001). Differences of ≥ 2 points occurred in 19%. Disagreement between mild and moderate severity occurred in 12% of patients. Other variables did not demonstrate significant relationships with mJOA scores. CONCLUSION: The inter-rater reliability of total mJOA and its subscores is good, except for UE sensory function (moderate). However, the vast majority of assessments differed between observers, indicating that this measure should be interpreted carefully, particularly when near the threshold between severity categories, or when a patient is reassessed for deterioration. Further efforts to educate clinicians on administration and to refine the UE sensory subscore may enhance the reliability of this tool.Level of Evidence: 1.

Propensity Score Matching: A Powerful Tool for Analyzing Observational Nonrandomized Data.

In using observational, nonrandomized data, there is often interest in studying the effect of a particular treatment on a specific outcome. However, the imbalance of potential confounding variables between the treatment groups can distort the relationship between treatment and outcome. Propensity score matching is one, increasingly utilized, method to help account for such imbalances, allowing for a more accurate estimation of the influence of treatment on outcome. In this paper, we provide the clinician with an overview of propensity score matching techniques and provide a practical example of how this has been used in clinical research relevant to spine surgery.

Prediction of independence in bowel function after spinal cord injury: validation of a logistic regression model.

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVES: Recently, logistic regression models were developed to predict independence in bowel function 1 year after spinal cord injury (SCI) on a multicenter European SCI (EMSCI) dataset. Here, we evaluated the external validity of these models against a prospectively accrued North American SCI dataset. SETTING: Twenty-five SCI centers in the United States and Canada. METHODS: Two logistic regression models developed by the EMSCI group were applied to data for 277 patients derived from three prospective multicenter SCI studies based in North America. External validation was evaluated for both models by assessing their discrimination, calibration, and clinical utility. Discrimination and calibration were assessed using ROC curves and calibration curves, respectively, while clinical utility was assessed using decision curve analysis. RESULTS: The simplified logistic regression model, which used baseline total motor score as the predictor, demonstrated the best performance, with an area under the ROC curve of 0.869 (95% confidence interval: 0.826-0.911), a sensitivity of 75.5%, and a specificity of 88.5%. Moreover, the model was well calibrated across the full range of observed probabilities and displayed superior clinical benefit on the decision curve. CONCLUSIONS: A logistic regression model using baseline total motor score as a predictor of independent bowel function 1 year after SCI was successfully validated against an external dataset. These findings provide evidence supporting the use of this model to enhance the care for individuals with SCI.

Machine learning algorithms for prediction of health-related quality-of-life after surgery for mild degenerative cervical myelopathy.

BACKGROUND: Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction worldwide. Current guidelines recommend management based on the severity of myelopathy, measured by the modified Japanese Orthopedic Association (mJOA) score. Patients with moderate to severe myelopathy, defined by an mJOA below 15, are recommended to undergo surgery. However, the management for mild myelopathy (mJOA between 15 and 17) is controversial since the response to surgery is more heterogeneous. PURPOSE: To develop machine learning algorithms predicting phenotypes of mild myelopathy patients that would benefit most from surgery. STUDY DESIGN: Retrospective subgroup analysis of prospectively collected data. PATIENT SAMPLES: Data were obtained from 193 mild DCM patients who underwent surgical decompression and were enrolled in the multicenter AOSpine CSM clinical trials. OUTCOME MEASURES: The mJOA score, an assessment of functional status, was used to isolate patients with mild DCM. The primary outcome measures were change from baseline for the Short Form-36 (SF-36) mental component summary (MCS) and physical component summary (PCS) at 1-year postsurgery. These changes were dichotomized according to whether they exceeded the minimal clinically important difference. METHODS: The data were split into training (75%) and testing (25%) sets. Model predictors included baseline demographic variables and clinical presentation. Seven machine learning algorithms and a logistic regression model were trained and optimized using the training set, and their performances were evaluated using the testing set. For each outcome (improvement in MCS or PCS), the machine learning algorithm with the greatest area under the curve (AUC) on the training set was selected for further analysis. RESULTS: The generalized boosted model (GBM) and earth models performed well in the prediction of significant improvement in MCS and PCS respectively, with AUCs of 0.72 to 0.78 on the training set. This performance was replicated on the testing set, in which the GBM and earth models showed AUCs of 0.77 and 0.78, respectively, as well as fair to good calibration across the predicted range of probabilities. Female patients with a low initial MCS were less likely to experience significant improvement in MCS than males. The presence of certain signs and symptoms (eg, lower limb spasticity, clumsy hands) were also predictive of worse outcome. CONCLUSIONS: Machine learning models showed good predictive power and provided information about the phenotypes of mild DCM patients most likely to benefit from surgical intervention. Overall, machine learning may be a useful tool for management of mild DCM, though external validation and prospective analysis should be performed to better solidify its role.

Safety and efficacy of riluzole in patients undergoing decompressive surgery for degenerative cervical myelopathy (CSM-Protect): a multicentre, double-blind, placebo-controlled, randomised, phase 3 trial.

BACKGROUND: Degenerative cervical myelopathy represents the most common form of non-traumatic spinal cord injury. This trial investigated whether riluzole enhances outcomes in patients undergoing decompression surgery for degenerative cervical myelopathy. METHODS: This multicentre, double-blind, placebo-controlled, randomised, phase 3 trial was done at 16 university-affiliated centres in Canada and the USA. Patients with moderate-to-severe degenerative cervical myelopathy aged 18-80 years, who had a modified Japanese Orthopaedic Association (mJOA) score of 8-14, were eligible. Patients were randomly assigned (1:1) to receive either oral riluzole (50 mg twice a day for 14 days before surgery and then for 28 days after surgery) or placebo. Randomisation was done using permuted blocks stratified by study site. Patients, physicians, and outcome assessors remained masked to treatment group allocation. The primary endpoint was change in mJOA score from baseline to 6 months in the intention-to-treat (ITT) population, defined as all individuals who underwent randomisation and surgical decompression. Adverse events were analysed in the modified intention-to-treat (mITT) population, defined as all patients who underwent randomisation, including those who did not ultimately undergo surgical decompression. This study is registered with ClinicalTrials.gov, NCT01257828. FINDINGS: From Jan 31, 2012, to May 16, 2017, 408 patients were screened. Of those screened, 300 were eligible (mITT population); 290 patients underwent decompression surgery (ITT population) and received either riluzole (n=141) or placebo (n=149). There was no difference between the riluzole and placebo groups in the primary endpoint of change in mJOA score at 6-month follow-up: 2·45 points (95% CI 2·08 to 2·82 points) versus 2·83 points (2·47 to 3·19), difference -0·38 points (-0·90 to 0·13; p=0·14). The most common adverse events were neck or arm or shoulder pain, arm paraesthesia, dysphagia, and worsening of myelopathy. There were 43 serious adverse events in 33 (22%) of 147 patients in the riluzole group and 34 serious adverse events in 29 (19%) of 153 patients in the placebo group. The most frequent severe adverse events were osteoarthrosis of non-spinal joints, worsening of myelopathy, and wound complications. INTERPRETATION: In this trial, adjuvant treatment for 6 weeks perioperatively with riluzole did not improve functional recovery beyond decompressive surgery in patients with moderate-to-severe degenerative cervical myelopathy. Whether riluzole has other benefits in this patient population merits further study. FUNDING: AOSpine North America.

The influence of timing of surgical decompression for acute spinal cord injury: a pooled analysis of individual patient data.

BACKGROUND: Although there is a strong biological rationale for early decompression of the injured spinal cord, the influence of the timing of surgical decompression for acute spinal cord injury (SCI) remains debated, with substantial variability in clinical practice. We aimed to objectively evaluate the effect of timing of decompressive surgery for acute SCI on long-term neurological outcomes. METHODS: We did a pooled analysis of individual patient data derived from four independent, prospective, multicentre data sources, including data from December, 1991, to March, 2017. Three of these studies had been published; of these, only one study previously specifically analysed the effect of the timing of surgical decompression. These four datasets were selected because they were among the highest quality acute SCI datasets available and contained highly granular data. Individual patient data were obtained by request from study authors. All patients who underwent decompressive surgery for acute SCI within these datasets were included. Patients were stratified into early (<24 h after spinal injury) and late (≥24 h after spinal injury) decompression groups. Neurological outcomes were assessed by American Spinal Injury Association (ASIA), or International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), examination. The primary endpoint was change in total motor score from baseline to 1 year after spinal injury. Secondary endpoints were ASIA Impairment Scale (AIS) grade and change in upper-extremity motor, lower-extremity motor, light touch, and pin prick scores after 1 year. One-stage meta-analyses were done by hierarchical mixed-effects regression adjusting for baseline score, age, mechanism of injury, AIS grade, level of injury, and administration of methylprednisolone. Effect sizes were summarised by mean difference (MD) for sensorimotor scores and common odds ratio (cOR) for AIS grade, with corresponding 95% CIs. As a secondary analysis, change in total motor score was regressed against time to surgical decompression (h) as a continuous variable, using a restricted cubic spline with adjustment for the same covariates as in the primary analysis. FINDINGS: We identified 1548 eligible patients from the four datasets. Outcome data at 1 year after spinal injury were available for 1031 patients (66·6%). Patients who underwent early surgical decompression (n=528) experienced greater recovery than patients who had late decompression surgery (n=1020) at 1 year after spinal injury; total motor scores improved by 23·7 points (95% CI 19·2-28·2) in the early surgery group versus 19·7 points (15·3-24·0) in the late surgery group (MD 4·0 points [1·7-6·3]; p=0·0006), light touch scores improved by 19·0 points (15·1-23·0) vs 14·8 points (11·2-18·4; MD 4·3 [1·6-7·0]; p=0·0021), and pin prick scores improved by 18·3 points (13·7-22·9) versus 14·2 points (9·8-18·6; MD 4·0 [1·5-6·6]; p=0·0020). Patients who had early decompression also had better AIS grades at 1 year after surgery, indicating less severe impairment, compared with patients who had late surgery (cOR 1·48 [95% CI 1·16-1·89]; p=0·0019). When time to surgical decompression was modelled as a continuous variable, there was a steep decline in change in total motor score with increasing time during the first 24-36 h after injury (p<0·0001); and after 36 h, change in total motor score plateaued. INTERPRETATION: Surgical decompression within 24 h of acute SCI is associated with improved sensorimotor recovery. The first 24-36 h after injury appears to represent a crucial time window to achieve optimal neurological recovery with decompressive surgery following acute SCI. FUNDING: None.