The Effects of Peri-Operative Adverse Events on Clinical and Patient-Reported Outcomes After Surgery for Degenerative Cervical Myelopathy: An Observational Cohort Study from the Canadian Spine Outcomes and Research Network.

BACKGROUND AND OBJECTIVES: There is a lack of data examining the effects of perioperative adverse events (AEs) on long-term outcomes for patients undergoing surgery for degenerative cervical myelopathy. We aimed to investigate associations between the occurrence of perioperative AEs and coprimary outcomes: (1) modified Japanese Orthopaedic Association (mJOA) score and (2) Neck Disability Index (NDI) score. METHODS: We analyzed data from 800 patients prospectively enrolled in the Canadian Spine Outcomes and Research Network multicenter observational study. The Spine AEs Severity system was used to collect intraoperative and postoperative AEs. Patients were assessed at up to 2 years after surgery using the NDI and the mJOA scale. We used a linear mixed-effect regression to assess the influence of AEs on longitudinal outcome measures as well as multivariable logistic regression to assess factors associated with meeting minimal clinically important difference (MCID) thresholds at 1 year. RESULTS: There were 167 (20.9%) patients with minor AEs and 36 (4.5%) patients with major AEs. The occurrence of major AEs was associated with an average increase in NDI of 6.8 points (95% CI: 1.1-12.4, P = .019) and reduction of 1.5 points for mJOA scores (95% CI: -2.3 to -0.8, P < .001) up to 2 years after surgery. Occurrence of major AEs reduced the odds of patients achieving MCID targets at 1 year after surgery for mJOA (odds ratio 0.23, 95% CI: 0.086-0.53, P = .001) and for NDI (odds ratio 0.34, 95% CI: 0.11-0.84, P = .032). CONCLUSION: Major AEs were associated with reduced functional gains and worse recovery trajectories for patients undergoing surgery for degenerative cervical myelopathy. Occurrence of major AEs reduced the probability of achieving mJOA and NDI MCID thresholds at 1 year. Both minor and major AEs significantly increased health resource utilization by reducing the proportion of discharges home and increasing length of stay.

Differences in the surgical management of degenerative lumbar spondylolisthesis based on self-reported sex: analysis of the CSORN prospective DLS study.

OBJECTIVE: Surgical treatment of degenerative lumbar spondylolisthesis (DLS) reliably improves patient-reported quality of life; however, patient population heterogeneity, in addition to other factors, ensures ongoing equipoise in choosing the ideal surgical treatment. Surgeon preference for fusion or decompression alone influences surgical treatment decision-making. Meanwhile, at presentation, patient-reported outcome measures (PROMs) differ considerably between females and males. The aims of this study were to determine whether there exists a difference in the rates of decompression and fusion versus decompression alone based on patient-reported sex, and to determine if widely accepted indications for fusion justify any observed differences or if surgeon preference plays a role. METHODS: This study is a retrospective cohort analysis of patients enrolled in the Canadian Spine Outcomes Research Network (CSORN) DLS study, a multicentered Canadian prospective study, investigating the surgical management and outcome of DLS. Decompression and fusion rates, patient characteristics, preoperative PROMs, and radiographic measures were compared between males and females before and after propensity score matching. RESULTS: In the unmatched cohort, female patients were more likely to undergo decompression and fusion than male patients. Females were more likely to have the recognized indications for fusion, including kyphotic disc angle, higher spondylolisthesis grade and slip percentage, and patient-reported back pain. Other radiographic findings associated with the decision to fuse, including facet effusion, facet distraction, or facet angle, were not more prevalent in females. After propensity score matching for demographic and radiographic characteristics, similar proportions of male and female patients underwent decompression and fusion and decompression alone. CONCLUSIONS: Although it remains unclear who should or should not undergo fusion, in addition to surgical decompression of DLS, female patients undergo fusion at a higher rate than their male counterparts. After matching baseline radiographic factors indicating fusion, this analysis showed that the decision to fuse was not biased by sex differences. Rather, the higher proportion of females undergoing fusion is largely explained by the radiographic and clinical indications for fusion, suggesting that specific clinical and anatomical features of this condition are indeed different between sexes.

Effectiveness of prophylactic intranasal photodynamic disinfection therapy and chlorhexidine gluconate body wipes for surgical site infection prophylaxis in adult spine surgery.

BACKGROUND: Current measures to prevent spinal surgical site infection (SSI) lack compliance and lead to antimicrobial resistance. We aimed to examine the effectiveness of bundled preoperative intranasal photodynamic disinfection therapy (nPDT) and chlorhexidine gluconate (CHG) body wipes in the prophylaxis of spine SSIs in adults, as well as determine our institutional savings attributable to the use of this strategy and identify adverse events reported with nPDT-CHG. METHODS: We performed a 14-year prospective observational interrupted time-series study in adult (age > 18 yr) patients undergoing emergent or elective spine surgery with 3 time-specific cohorts: before rollout of our institution's nPDT-CHG program (2006-2010), during rollout (2011-2014) and after rollout (2015-2019). We used unadjusted bivariate analysis to test for temporal changes across patient and surgical variables, and segmented regression to estimate the effect of nPDT-CHG on the annual SSI incidence rates per period. We used 2 models to estimate the cost of nPDT-CHG to prevent 1 additional SSI per year and the annual cumulative cost savings through SSI prevention. RESULTS: Over the study period, 13 493 patients (mean 964 per year) underwent elective or emergent spine surgery. From 2006 to 2019, the mean age, mean Charlson Comorbidity Index (CCI) score and mean Spine Surgical Invasiveness Index (SSII) score increased from 48.4 to 58.1 years, from 1.7 to 2.6, and from 15.4 to 20.5, respectively (p < 0.001). Unadjusted analysis confirmed a significant decrease in the annual number (74.6 to 26.8) and incidence (7.98% to 2.67%) of SSIs with nPDT-CHG (p < 0.001). After adjustment for mean age, mean CCI score and mean SSII score, segmented regression showed an absolute reduction in the annual SSI incidence rate of 3.36% per year (p < 0.001). The estimated annual cost to prevent 1 additional SSI per year was about $1350-$1650, and the estimated annual cumulative cost savings were $2 484 856-$2 495 016. No adverse events were reported with nPDT-CHG. CONCLUSION: Preoperative nPDT-CHG administration is an effective prophylactic strategy for spinal SSIs, with significant cost savings. Given its rapid action, minimal risk of antimicrobial resistance, broad-spectrum activity and high compliance rate, preoperative nPDT-CHG decolonization should be the standard of care for all patients undergoing emergent or elective spine surgery.

Design of an ultrasound-emitting drill guide for freehand pedicle screw navigation.

BACKGROUND: Accurate pedicle screw placement in spinal surgery is critical as inaccuracies can lead to morbidity and suboptimal outcomes. Navigation and robotics have reduced malplacement rates, but their adoption is limited by high costs, learning curves, surgical time, and radiation. The authors propose an ultrasound-emitting and self-localising drill guide for precise screw placement that overcomes the limitations of current techniques. MATERIALS AND METHODS: The preliminary configuration analysis involves systematically varying design parameters and assessing localization performance using lumbar spine MRI based simulations. The authors evaluate localization techniques based on accuracy and optimization capture range. RESULTS: Results suggest that feasible designs can accurately estimate position. A promising design features a 5 mm radius cannula with ten 35mm-long ultrasound strips, 32 elements per strip, and a fanned-out emission profile. A multi-start active-set optimization algorithm with six initial estimates ensures reliable and efficient localization. CONCLUSIONS: The simulation suggests that the proposed design can achieve sufficient localization accuracy for pedicle screw navigation. These findings will guide the fabrication of a novel ultrasound-emitting drill guide for further evaluation and physical testing.

Impact of Specialized Versus Non-Specialized Acute Hospital Care on Survival Among Patients With Acute Incomplete Traumatic Spinal Cord Injuries: A Population-Based Observational Study from British Columbia, Canada.

Given the complexity of care necessitated after an acute traumatic spinal cord injury (SCI), it seems intuitively beneficial for such care to be delivered at hospitals with specialized SCI expertise. Demonstrating these benefits is not straightforward, however. We sought to determine whether specialized acute hospital care influenced the most fundamental outcomes after SCI: mortality within the first year of injury. We compared survival among patients with incomplete tSCI admitted to a single quaternary-level trauma hospital with a specialized acute SCI program versus those admitted to trauma hospitals without specialized acute SCI care. We performed a population-based retrospective observational cohort study using administrative and clinical data linked from multiple sources in British Columbia (BC) from 2001 to 2017. Among a cohort of 1920 patients, there were 193 deaths within one year. We failed to identify a significant overall benefit for survival after adjusting for potential confounders, and the confidence intervals (CIs) were compatible with both benefit and harm (odds ratio [OR] 1.01, 95% CI 0.17 to 6.11, p = 0.99). Significant associations were observed with age greater than 65 (OR 4.92, 95% CI 1.66 to 14.57, p < 0.01), Charlson Comorbidity Index (OR 1.61, 95% CI 1.42 to 1.83, p < 0.01), Injury Severity Score (OR 1.08, 95% CI 1.06 to 1.11, p < 0.01), and traumatic brain injury (OR 2.12, 95% CI 1.32 to 3.41, p < 0.01). Among patients with acute tSCI, admission to a hospital with specialized acute SCI care was not associated with improved overall one-year survival. Subgroup analyses, however, suggested heterogeneity of effects, with little benefit for older patients with less polytrauma and substantial benefit for younger patients with greater polytrauma.

Functional outcomes correlate with sagittal spinal balance in degenerative lumbar spondylolisthesis surgery.

BACKGROUND CONTEXT: Degenerative lumbar spondylolisthesis (DLS) is a debilitating condition associated with poor preoperative functional status. Surgical intervention has been shown to improve functional outcomes in this population though the optimal surgical procedure remains controversial. The importance of maintaining and/or improving sagittal and pelvic spinal balance parameters has received increasing interest in the recent DLS literature. However, little is known about the radiographic parameters most associated with improved functional outcomes among patients undergoing surgery for DLS. PURPOSE: To identify the effect of postoperative sagittal spinal alignment on functional outcome after DLS surgery. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Two-hundred forty-three patients in the Canadian Spine Outcomes and Research Network (CSORN) prospective DLS study database. OUTCOME MEASURES: Baseline and 1-year postoperative leg and back pain on the 10-point Numeric Rating Scale and baseline and 1-year postoperative disability on the Oswestry Disability Index (ODI). METHODS: All enrolled study patients had a DLS diagnosis and underwent decompression in isolation or with posterolateral or interbody fusion. Global and regional radiographic alignment parameters were measured at baseline and 1-year postoperatively including sagittal vertical axis (SVA), pelvic incidence and lumbar lordosis (LL). Both univariate and multiple linear regression was used to assess for the association between radiographic parameters and patient-reported functional outcomes with adjustment for possible confounding baseline patient factors. RESULTS: Two-hundred forty-three patients were available for analysis. Among participants, the mean age was 66 with 63% (153/243) female with the primary surgical indication of neurogenic claudication in 197/243 (81%) of patients. Worse pelvic incidence-LL mismatch was correlated with more severe disability [ODI, 0.134, p<.05), worse leg pain (0.143, p<.05) and worse back pain (0.189, p<.001) 1-year postoperatively. These associations were maintained after adjusting for age, BMI, gender, and preoperative presence of depression (ODI, R2 0.179, ß, 0.25, 95% CI 0.08, 0.42, p=.004; back pain R2 0.152 (ß, 0.05, 95% CI 0.022, 0.07, p<.001; leg pain score R2 0.059, ß, 0.04, 95% CI 0.008, 0.07, p=.014). Likewise, reduction of LL was associated with worse disability (ODI, R2 0.168, ß, 0.04, 95% CI -0.39, -0.02, p=.027) and worse back pain (R2 0.135, ß, -0.04, 95% CI -0.06, -0.01, p=.007). Worsened SVA correlated with worse patient reported functional outcomes (ODI, R2 0.236, ß, 0.12, 95% CI 0.05, 0.20, p=.001). Similarly, an increase (worsening) in SVA resulted in a worse NRS back pain (R2 0.136, ß, 0.01, 95% CI .001, 0.02, p=.029) and worse NRS leg pain (R2 0.065, ß, 0.02, 95% CI 0.002, 0.02, p=.018) scores regardless of surgery type. CONCLUSIONS: Preoperative emphasis on regional and global spinal alignment parameters should be considered in order to optimize functional outcome in lumbar degenerative spondylolisthesis treatment.

Degenerative spinal conditions requiring emergency surgery: an evolving crisis in a publicly funded health care system.

BACKGROUND: Surgery for degenerative spine pathologies is typically performed on a scheduled basis; however, worsening symptoms may warrant emergency surgery. An increasing number of patients requiring emergency surgery has been observed (22.6% in 2006 to 34.8% in 2019). We sought to compare the outcomes of patients who received scheduled surgery and those who required emergency surgery. METHODS: All patients treated between Jan. 1, 2006, and Dec. 31, 2019, were included. Retrospective comparisons were made between patients who were scheduled (elective) for surgery and those requiring emergency surgery, patients who were scheduled for surgery and those who decompensated while on the surgical waitlist and patients who presented as de novo emergencies and those who decompensated while on the surgical waitlist. RESULTS: Among the 6217 patients with degenerative pathologies, 4654 (74.9%) patients were scheduled (elective) for surgery and 1563 (25.1%) were patients requiring emergency surgery. Compared with patients who were scheduled, patients requiring emergency surgery had a longer length of stay (LOS) in hospital (5.1 d, interquartile range [IQR] 2.7-11.2 v. 3.6 d, IQR 1.3-6.4, p < 0.001) and lower rate of home discharge (78.6% v. 94.2%, p < 0.001). Patients requiring emergency surgery were 1.34 times more likely to have any adverse events (95% confidence interval [CI] 1.06-1.68, p = 0.01). When compared with patients who were scheduled for surgery, those who decompensated while on the surgical waitlist had longer LOS (7.0 d, IQR 3.3-15.0 v. 3.6 d, IQR 1.3-6.4, p < 0.001), less home discharge (77.6% v. 94.2%, p < 0.001) and were 2.5 times more likely to have any adverse events (95% CI 1.5-4.1, p < 0.001). Patients who decompensated had a 2.1 times higher risk of having any adverse events than patients who presented as de novo emergencies (95% CI 1.2-3.6, p < 0.001). CONCLUSION: We observed worse perioperative outcomes for patients requiring emergency surgery for degenerative spinal conditions than for patients who were scheduled for surgery. Patients who decompensated while on the surgical waitlist had the worst outcomes.

The Role of Frailty and Sarcopenia in Predicting Major Adverse Events, Length of Stay and Reoperation Following En Bloc Resection of Primary Tumours of the Spine.

STUDY DESIGN: Retrospective observational cohort study. OBJECTIVE: En bloc resection for primary tumours of the spine is associated with a high rate of adverse events (AEs). The objective was to explore the relationship between frailty/sarcopenia and major perioperative AEs, length of stay (LOS), and unplanned reoperation following en bloc resection of primary spinal tumours. METHODS: This is a unicentre study consisting of adult patients undergoing en bloc resection for a primary spine tumor. Frailty was calculated with the modified frailty index (mFI) and spine tumour frailty index (STFI). Sarcopenia was quantified with the total psoas area/vertebral body area ratio (TPA/VB) at L3 and L4. Univariable regression analysis was used to quantify the association between frailty/sarcopenia and major perioperative AEs, LOS and unplanned reoperation. RESULTS: 95 patients met the inclusion criteria. The mFI and STFI identified a frailty prevalence of 3% and 18%. Mean CT TPA/VB ratios were 1.47 (SD ± .05) and 1.83 (SD ± .06) at L3 and L4. Inter-observer reliability was .93 and .99 for CT and MRI L3 and L4 TPA/VB ratios. Unadjusted analysis demonstrated sarcopenia and mFI did not predict perioperative AEs, LOS or unplanned reoperation. Frailty defined by an STFI score ≥2 predicted unplanned reoperation for surgical site infection (SSI) (P < .05). CONCLUSIONS: The STFI was only associated with unplanned reoperation for SSI on unadjusted analysis, while the mFI and sarcopenia were not predictive of any outcome. Further studies are needed to investigate the relationship between frailty, sarcopenia and perioperative outcomes following en bloc resection of primary spinal tumors.

Generic versus disease-specific adverse event reporting: a comparison of the NSQIP and SAVES databases for the identification of acute care adverse events in adult spine surgery.

OBJECTIVE: The accurate identification and reporting of adverse events (AEs) is crucial for quality improvement. A myriad of AE systems are utilized. There is a lack of understanding of the differences between prospective versus retrospective, disease-specific versus generic, and point-of-care versus chart-abstracted systems. The objective of this study was to compare the benefits and limitations between the prospective, disease-specific, point-of-care Spine Adverse Events Severity System (SAVES) and the retrospective, generic, and chart-abstracted National Surgical Quality Improvement Program (NSQIP) for the identification and reporting of AEs in adult patients undergoing spinal surgery. METHODS: The authors conducted an observational ambidirectional cohort study of adult patients undergoing spine surgery other than for trauma between 2011 and 2019 in a quaternary spine center. Patients were identified using Current Procedural Terminology codes in the NSQIP database and matched using unique medical record numbers to their corresponding record in SAVES. The incidence of AEs and per-patient AEs as recorded in NSQIP and SAVES was the primary outcome of interest. Comparable AEs were identified by matching NSQIP AEs to equivalent ones in SAVES. Chi-square tests were used to test for significant differences in the incidence of overall and comparable AEs between the databases. RESULTS: There were 2198 patients identified in NSQIP, of whom 2033 also had complete records in SAVES. SAVES identified 5342 individual AEs in 1484 patients (73%) compared with 1291 individual AEs in 807 patients (39.7%) with the NSQIP database (p < 0.001). SAVES identified 250 intraoperative and 422 postoperative spine-specific AEs that NSQIP did not record. NSQIP captured a greater number of AEs beyond 30 days, including prolonged length of stay > 30 days, unplanned readmission, unplanned reoperation, and death later than 30 days after surgery compared with SAVES. CONCLUSIONS: SAVES captures a greater incidence of peri- and intraoperative spine-specific AEs than NSQIP, while NSQIP identifies a greater number of AEs beyond 30 days. While a prospective, disease-specific, point-of-care AE system such as SAVES is specific for guiding quality improvement in spine surgery, it incurs greater time and financial costs. Conversely, a retrospective, generic, and chart-abstracted system such as NSQIP provides equivocal cross-institutional comparability with reduced time and financial costs. Specific contextual and aim-specific needs should guide the choice and implementation of an AE system.

Patient's expectations of surgery for lumbar degenerative spondylolisthesis: analysis by type of surgery and patient factors from the Canadian Spine Outcomes and Research Network (CSORN).

BACKGROUND CONTEXT: Preoperative expectations influence postoperative outcomes. Patients with lumbar degenerative spondylolisthesis have especially high expectations of pain relief and overall functional well-being compared to patients with lumbar stenosis. PURPOSE: The primary objective was to analyze preoperative expectations of lumbar DS patients with respect to the type of surgery proposed (decompression vs decompression and fusion). Secondarily, we aimed to assess the associations between preoperative expectations and patient and clinical factors as well as postoperative expectations fulfillment. STUDY DESIGN/SETTING: Patients were prospectively enrolled in a multicenter, prospective cohort study evaluating the assessment and management of degenerative spondylolisthesis utilizing the infrastructure of the Canadian Spine Outcomes and Research Network (CSORN) surgical registry. PATIENT SAMPLE: Patients with a diagnosis of degenerative spondylolisthesis with symptoms of neurogenic claudication or radiculopathy with or without back pain, unresponsive to nonoperative management over at least 3 months were included. Patients who underwent decompression, decompression and posterolateral fusion or decompression and interbody fusion at Canadian spine centers between January 2015 and September 2021 were included. OUTCOME MEASURES: The North American Spine Society Lumbar Spine Questionnaire was utilized for expectations measurement. The expectation questionnaire was completed following consent and before surgery and at 1 year. METHODS: Expectations for pain relief and improvements in overall functional well-being were rated on a scale of 0 to 100. Preoperative expectation in terms of pain relief and functional well-being score were calculated. Multivariate linear regression was used to evaluate the association between expected preoperative patient factors and pain relief and functional well-being. The factors associated with the most important expectation were evaluated using multivariable multinomial logistic regression. RESULTS: Three hundred fifty-two patients were included with 100 patients undergoing decompression and 252 patients also undergoing fusion. The seven items of preoperative expectations did not differ between the procedure groups nor did expected change. The mean pain relief and overall functional well-being expectation scores did not significantly differ between procedures. Higher expectations were associated with having more comorbidities [ß=-2.0 (SE 0.8), p=.020], being physically active [ß=8.4 (SE 3.2), p=.010] and having more leg pain [ß=1.6 (SE 0.7), p=.015]. Better perceived physical health measured by SF12 PCS was associated with lower expectation of pain relief [ß= -0.4 (SE 0.2), p=.039] and functional well-being [ß=-0.84 (SE 0.2), p=.001]. Better perceived mental health measured by SF12 MCS was associated with lower expectation of functional well-being [ß=-0.8 (SE 0.2), p=.001]. Postoperative expectations fulfillment did not differ between procedures. CONCLUSION: Preoperative expectations in terms of pain relief and functional well-being were similar between the two most common procedures performed, decompression ± fusion. Secondarily, higher preoperative expectations were associated with greater pain, disability and being physically active. Expectations fulfillment did not differ between procedures.

Patient, clinical, surgical, and institutional factors associated with length of stay in scheduled degenerative thoracolumbar spine surgery: National Multicenter Cohort Analysis from the Canadian Spine Outcomes and Research Network.

OBJECTIVE: Length of stay (LOS) is a contributor to costs and resource utilization. The primary goal of this study was to identify patient, clinical, surgical, and institutional variables that influence LOS after elective surgery for thoracolumbar degenerative pathology. The secondary objective was to examine variability in LOS and institutional strategies used to decrease LOS. METHODS: This is a retrospective study of prospectively collected data from a multicentric cohort enrolled in the Canadian Spine Outcomes and Research Network (CSORN) between January 2015 and October 2020 who underwent elective thoracolumbar surgery (discectomy [1 or 2 levels], laminectomy [1 or 2 levels], and posterior instrumented fusion [up to 5 levels]). Prolonged LOS was defined as LOS greater than the median. Logistic regression models were used to determine factors associated with prolonged LOS for each procedure. A survey was sent to the principal investigators of the participating healthcare institutions to understand institutional practices that are used to decrease LOS. RESULTS: A total of 3700 patients were included (967 discectomies, 1094 laminectomies, and 1639 fusions). The median LOSs for discectomy, laminectomy, and fusion were 0.0 (IQR 1.0), 1.0 (IQR 2.0), and 4.0 (IQR 2.0) days, respectively. On multivariable analysis, predictors of prolonged LOS for discectomy were having more leg pain, higher Oswestry Disability Index (ODI) scores, symptom duration more than 2 years, having undergone an open procedure, occurrence of an adverse event (AE), and treatment at an institution without protocols to reduce LOS (p < 0.05). Predictors of prolonged LOS for laminectomy were increased age, living alone, higher ODI scores, higher BMI, open procedures, longer operative time, AEs, and treatment at an institution without protocols to reduce LOS (p < 0.05). For posterior instrumented fusion, predictors of prolonged LOS were older age, living alone, more comorbidities, higher ODI scores, longer operative time, AEs, and treatment at an institution without protocols to reduce LOS (p < 0.05). The laminectomy group had the largest variability in LOS (SD 4.4 days, range 0-133 days). Three hundred fifty-four patients (22%) had an LOS above the 75th percentile. Ten institutions (53%) had either Enhanced Recovery After Surgery or standardized protocols in place. CONCLUSIONS: Among the factors identified in this study, worse baseline ODI scores, experiencing AEs, and treatment at an institution without protocols aimed at reducing LOS were predictive of prolonged LOS in all surgical groups. The laminectomy group had the largest variability in LOS.

Association of CSF and Serum Neurofilament Light and Glial Fibrillary Acidic Protein, Injury Severity, and Outcome in Spinal Cord Injury.

BACKGROUND AND OBJECTIVES: Traumatic spinal cord injury (SCI) is highly heterogeneous, and tools to better delineate pathophysiology and recovery are needed. Our objective was to profile the response of 2 biomarkers, neurofilament light (NF-L) and glial fibrillary acidic protein (GFAP), in the serum and CSF of patients with acute SCI to evaluate their ability to objectively characterize injury severity and predict neurologic recovery. METHODS: Blood and CSF samples were obtained from prospectively enrolled patients with acute SCI through days 1-4 postinjury, and the concentration of NF-L and GFAP was quantified using Simoa technology. Neurologic assessments defined the ASIA Impairment Scale (AIS) grade and motor score (MS) at presentation and 6 months postinjury. RESULTS: One hundred eighteen patients with acute SCI (78 AIS A, 20 AIS B, and 20 AIS C) were enrolled, with 113 (96%) completing 6-month follow-up. NF-L and GFAP levels were strongly associated between paired serum and CSF specimens, were both increased with injury severity, and distinguished among baseline AIS grades. Serum NF-L and GFAP were significantly (p = 0.02 to <0.0001) higher in AIS A patients who did not improve at 6 months, predicting AIS grade conversion with a sensitivity and specificity (95% CI) of 76% (61, 87) and 77% (55, 92) using NF-L and 72% (57, 84) and 77% (55, 92) using GFAP at 72 hours, respectively. Independent of clinical baseline assessment, a serum NF-L threshold of 170 pg/mL at 72 hours predicted those patients who would be classified as motor complete (AIS A/B) compared with motor incomplete (AIS C/D) at 6 months with a sensitivity of 87% (76, 94) and specificity of 84% (69, 94); a serum GFAP threshold of 13,180 pg/mL at 72 hours yielded a sensitivity of 90% (80, 96) and specificity of 84% (69, 94). DISCUSSION: The potential for NF-L and GFAP to classify injury severity and predict outcome after acute SCI will be useful for patient stratification and prognostication in clinical trials and inform communication of prognosis. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that higher serum NF-L and GFAP are associated with worse neurological outcome after acute SCI. TRIAL REGISTRATION INFORMATION: Registered on ClinicalTrials.gov: NCT00135278 (March 2006) and NCT01279811 (January 2012).

Factors contributing to a longer length of stay in adults admitted to a quaternary spinal care center.

BACKGROUND: Longer hospital length of stay (LOS) has been associated with worse outcomes and increased resource utilization. However, diagnostic and patient-level factors associated with LOS have not been well studied on a large scale. The goal was to identify patient, surgical and organizational factors associated with longer patient LOS for adult patients at a high-volume quaternary spinal care center. METHODS: We performed a retrospective analysis of 13,493 admissions from January 2006 to December 2019. Factors analyzed included age, sex, admission status (emergent vs scheduled), ASIA grade, operative vs non-operative management, mean blood loss, operative time, and adverse events. Specific adverse events included surgical site infection (SSI), other infection (systemic or UTI), neuropathic pain, delirium, dural tear, pneumonia, and dysphagia. Diagnostic categories included trauma, oncology, deformity, degenerative, and "other". A multivariable linear regression model was fit to log-transformed LOS to determine independent factors associated with patient LOS, with effects expressed as multipliers on mean LOS. RESULTS: Mean LOS for the population (SD) was 15.8 (34.0) days. Factors significantly (p < 0.05) associated with longer LOS were advanced patient age [multiplier on mean LOS 1.011/year (95% CI: 1.007-1.015)], emergency admission [multiplier on mean LOS 1.615 (95% CI: 1.337-1.951)], ASIA grade [multiplier on mean LOS 1.125/grade (95% CI: 1.051-1.205)], operative management [multiplier on mean LOS 1.211 (95% CI: 1.006-1.459)], and the occurrence of one or more AEs [multiplier on mean LOS 2.613 (95% CI: 2.188-3.121)]. Significant AEs included postoperative SSI [multiplier on mean LOS 1.749 (95% CI: 1.250-2.449)], other infections (systemic infections and UTI combined) [multiplier on mean LOS 1.650 (95% CI: 1.359-2.004)], delirium [multiplier on mean LOS 1.404 (95% CI: 1.103-1.787)], and pneumonia [multiplier on mean LOS 1.883 (95% CI: 1.447-2.451)]. Among the diagnostic categories explored, degenerative patients experienced significantly shorter LOS [multiplier on mean LOS 0.672 (95%CI: 0.535-0.844), p < 0.001] compared to non-degenerative categories. CONCLUSION: This large-scale study taking into account diagnostic categories identified several factors associated with patient LOS. Future interventions should target modifiable factors to minimize LOS and guide hospital resource allocation thereby improving patient outcomes and quality of care and decreasing healthcare-associated costs.

Muscle activity with 0.5 T upright MRI-DESS to measure T2 in biceps and triceps.

The purpose of this study was to determine if muscle activity of the biceps followed by isometric flexion changes T2 measured in the biceps. It is hypothesized that an increase in T2 will be observed in the biceps but not in the triceps after flexion exercise. Ten healthy volunteers were imaged with a one-channel neck coil while seated in a 0.5 T upright open magnetic resonance imaging (MRI) scanner using a three-dimensional double echo steady-state (DESS) sequence. Volunteers were imaged while relaxing their arm for 10, 20, and 30 min during an isometric biceps flexion immediately following performance of biceps curls to exhaustion, and again after relaxing for 10 and 20 min. Voxel-wise T2 was calculated by fitting to a DESS signal equation in regions segmented at muscle centers to determine mean T2 . During isometric biceps flexion immediately following biceps curls, mean T2 increased (average 33%, p < 0.05) in the biceps but not in the triceps. By 20 min after curls, mean T2 decreased (p < 0.05), and was near preactivity values. In contrast, there was no change in triceps T2 across any activity or postactivity time points. Intra-rater repeatability was excellent (ICC: 0.90-0.97). This study demonstrated that measuring T2 in an active muscle is feasible using a DESS sequence in an upright open MRI scanner. This could enable the study of muscle function while the muscle is working and weight-bearing, rather than of the "fatigue" of the muscles after activity. In comparison to electromyography, MRI also enables the study of deep muscles and allows simultaneous assessment of activity and function.

Pattern of neurological recovery in persons with an acute cervical spinal cord injury over the first 14 days post injury.

Introduction: Following a traumatic spinal cord injury (SCI) it is critical to document the level and severity of injury. Neurological recovery occurs dynamically after injury and a baseline neurological exam offers a snapshot of the patient's impairment at that time. Understanding when this exam occurs in the recovery process is crucial for discussing prognosis and acute clinical trial enrollment. The objectives of this study were to: (1) describe the trajectory of motor recovery in persons with acute cervical SCI in the first 14 days post-injury; and (2) evaluate if the timing of the baseline neurological assessment in the first 14 days impacts the amount of motor recovery observed. Methods: Data were obtained from the Rick Hansen Spinal Cord Injury Registry (RHSCIR) site in Vancouver and additional neurological data was extracted from medical charts. Participants with a cervical injury (C1-T1) who had a minimum of three exams (including a baseline and discharge exam) were included. Data on the upper-extremity motor score (UEMS), total motor score (TMS) and American Spinal Injury Association (ASIA) Impairment Scale (AIS) were included. A linear mixed-effect model with additional variables (AIS, level of injury, UEMS, time, time2, and TMS) was used to explore the pattern and amount of motor recovery over time. Results: Trajectories of motor recovery in the first 14 days post-injury showed significant improvements in both TMS and UEMS for participants with AIS B, C, and D injuries, but was not different for high (C1-4) vs. low (C5-T1) cervical injuries or AIS A injuries. The timing of the baseline neurological examination significantly impacted the amount of motor recovery in participants with AIS B, C, and D injuries. Discussion: Timing of baseline neurological exams was significantly associated with the amount of motor recovery in cervical AIS B, C, and D injuries. Studies examining changes in neurological recovery should consider stratifying by severity and timing of the baseline exam to reduce bias amongst study cohorts. Future studies should validate these estimates for cervical AIS B, C, and D injuries to see if they can serve as an "adjustment factor" to control for differences in the timing of the baseline neurological exam.

Network analysis of multimorbidity and health outcomes among persons with spinal cord injury in Canada.

Introduction: Multimorbidity, defined as the coexistence of two or more health conditions, is common in persons with spinal cord injury (SCI). Network analysis is a powerful tool to visualize and examine the relationship within complex systems. We utilized network analysis to explore the relationship between 30 secondary health conditions (SHCs) and health outcomes in persons with traumatic (TSCI) and non-traumatic SCI (NTSCI). The study objectives were to (1) apply network models to the 2011-2012 Canadian SCI Community Survey dataset to identify key variables linking the SHCs measured by the Multimorbidity Index-30 (MMI-30) to healthcare utilization (HCU), health status, and quality of life (QoL), (2) create a short form of the MMI-30 based on network analysis, and (3) compare the network-derived MMI to the MMI-30 in persons with TSCI and NTSCI. Methods: Three network models (Gaussian Graphical, Ising, and Mixed Graphical) were created and analyzed using standard network measures (e.g., network centrality). Data analyzed included demographic and injury variables (e.g., age, sex, region of residence, date, injury severity), multimorbidity (using MMI-30), HCU (using the 7-item HCU questionnaire and classified as "felt needed care was not received" [HCU-FNCNR]), health status (using the 12-item Short Form survey [SF-12] Physical and Mental Component Summary [PCS-12 and MCS-12] score), and QoL (using the 11-item Life Satisfaction questionnaire [LiSAT-11] first question and a single item QoL measure). Results: Network analysis of 1,549 participants (TSCI: 1137 and NTSCI: 412) revealed strong connections between the independent nodes (30 SHCs) and the dependent nodes (HCU-FNCNR, PCS-12, MCS-12, LiSAT-11, and the QoL score). Additionally, network models identified that cancer, deep vein thrombosis/pulmonary embolism, diabetes, high blood pressure, and liver disease were isolated. Logistic regression analysis indicated the network-derived MMI-25 correlated with all health outcome measures (p <0.001) and was comparable to the MMI-30. Discussion: The network-derived MMI-25 was comparable to the MMI-30 and was associated with inadequate HCU, lower health status, and poor QoL. The MMI-25 shows promise as a follow-up screening tool to identify persons living with SCI at risk of having poor health outcomes.

Dysfunctional paraspinal muscles in adult spinal deformity patients lead to increased spinal loading.

PURPOSE: Decreased spinal extensor muscle strength in adult spinal deformity (ASD) patients is well-known but poorly understood; thus, this study aimed to investigate the biomechanical and histopathological properties of paraspinal muscles from ASD patients and predict the effect of altered biomechanical properties on spine loading. METHODS: 68 muscle biopsies were collected from nine ASD patients at L4-L5 (bilateral multifidus and longissimus sampled). The biopsies were tested for muscle fiber and fiber bundle biomechanical properties and histopathology. The small sample size (due to COVID-19) precluded formal statistical analysis, but the properties were compared to literature data. Changes in spinal loading due to the measured properties were predicted by a lumbar spine musculoskeletal model. RESULTS: Single fiber passive elastic moduli were similar to literature values, but in contrast, the fiber bundle moduli exhibited a wide range beyond literature values, with 22% of 171 fiber bundles exhibiting very high elastic moduli, up to 20 times greater. Active contractile specific force was consistently less than literature, with notably 24% of samples exhibiting no contractile ability. Histological analysis of 28 biopsies revealed frequent fibro-fatty replacement with a range of muscle fiber abnormalities. Biomechanical modelling predicted that high muscle stiffness could increase the compressive loads in the spine by over 500%, particularly in flexed postures. DISCUSSION: The histopathological observations suggest diverse mechanisms of potential functional impairment. The large variations observed in muscle biomechanical properties can have a dramatic influence on spinal forces. These early findings highlight the potential key role of the paraspinal muscle in ASD.

Biomechanical Properties of Paraspinal Muscles Influence Spinal Loading-A Musculoskeletal Simulation Study.

Paraspinal muscles are vital to the functioning of the spine. Changes in muscle physiological cross-sectional area significantly affect spinal loading, but the importance of other muscle biomechanical properties remains unclear. This study explored the changes in spinal loading due to variation in five muscle biomechanical properties: passive stiffness, slack sarcomere length (SSL), in situ sarcomere length, specific tension, and pennation angle. An enhanced version of a musculoskeletal simulation model of the thoracolumbar spine with 210 muscle fascicles was used for this study and its predictions were validated for several tasks and multiple postures. Ranges of physiologically realistic values were selected for all five muscle parameters and their influence on L4-L5 intradiscal pressure (IDP) was investigated in standing and 36° flexion. We observed large changes in IDP due to changes in passive stiffness, SSL, in situ sarcomere length, and specific tension, often with interesting interplays between the parameters. For example, for upright standing, a change in stiffness value from one tenth to 10 times the baseline value increased the IDP only by 91% for the baseline model but by 945% when SSL was 0.4 µm shorter. Shorter SSL values and higher stiffnesses led to the largest increases in IDP. More changes were evident in flexion, as sarcomere lengths were longer in that posture and thus the passive curve is more influential. Our results highlight the importance of the muscle force-length curve and the parameters associated with it and motivate further experimental studies on in vivo measurement of those properties.

Preoperative Patient-reported Outcomes are not Associated With Sagittal and Spinopelvic Alignment in Degenerative Lumbar Spondylolisthesis.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim of this study was to evaluate whether sagittal and spinopelvic alignment correlate with preoperative patient-reported outcomes (PROs) in degenerative lumbar spondylolisthesis (DLS) with spinal stenosis. SUMMARY OF BACKGROUND DATA: Positive global sagittal balance and spinopelvic malalignment are strongly correlated with symptom severity in adult spinal deformity, but this correlation has not been evaluated in DLS. METHODS: Patients were enrolled in the Canadian Spine Outcomes Research Network (CSORN) prospective DLS study at seven centers between January 2015 and May 2018. Correlation was assessed between the following preoperative PROs: Oswestry Disability Index (ODI), numeric rating scale (NRS) leg pain, and NRS back pain and the following preoperative sagittal radiographic parameters SS, PT, PI, SVA, LL, TK, T1SPI, T9SPI, and PI-LL. Patients were further divided into groups based on spinopelvic alignment: Group 1 PI-LL<10°; Group 2 PI-LL ≥10° with PT <30°; and Group 3 PI-LL ≥10° with PT ≥30°. Preoperative PROs were compared among these three groups and were further stratified by those with SVA <50 mm and SVA ≥50 mm. RESULTS: A total of 320 patients (61% female) with mean age of 66.1 years were included. Mean (SD) preoperative PROs were: NRS leg pain 7.4 (2.1), NRS back pain 7.1 (2.0), and ODI 45.5 (14.5). Preoperative radiographic parameters included: SVA 27.1 (33.4) mm, LL 45.7 (13.4°), PI 57.6 (11.9), and PI-LL 11.8 (14.0°). Weak but statistically significant correlations were observed between leg pain and PT (r = -0.114) and PI (ρ = -0.130), and T9SPI with back pain ( r  = 0.130). No significant differences were observed among the three groups stratified by PI-LL and PT. No significant differences in PROs were observed between patients with SVA <50 mm compared to those with SVA ≥50 mm. CONCLUSION: Sagittal and spinopelvic malalignment do not appear to significantly influence baseline PROs in patients with DLS. LEVEL OF EVIDENCE: Prognostic level II.

The measurements of frailty and their possible application to spinal conditions: a systematic review.

BACKGROUND CONTEXT: Frailty is associated with an increased risk of postoperative adverse events (AEs) within the surgical spine population. Multiple frailty tools have been reported in the surgical spine literature. However, the applicability of these tools remains unclear. PURPOSE: Primary objective is to appraise the construct, feasibility, objectivity, and clinimetric properties of frailty tools reported in the surgical spine literature. Secondary objectives included determining the applicability and the most sensitive surgical spine population for each tool. STUDY DESIGN: Systematic Review. PATIENT SAMPLE: Studies reporting the use of a clinical frailty tool with a defined methodology in the adult surgical population (age ≥18 years). OUTCOME MEASURES: Postoperative adverse events (AEs) including mortality, major and minor morbidity, length of stay (LOS), unplanned readmission and reoperation, admission to the Intensive Care Unit (ICU), and adverse discharge disposition; postoperative patient-reported outcomes (health-related quality of life (HRQoL), functional, cognitive, and symptomatic); radiographic outcomes; and postoperative frailty trajectory. METHODS: This systematic review was registered with PROSPERO: CRD42019109045. Publications from January 1950 to December 2020 were identified by a comprehensive search of PubMed, Ovid, and Embase, supplemented by manual screening. Studies reporting and validating a frailty tool in the surgical spine population with a measurable outcome were included. Each tool and its clinimetric properties were evaluated using validated criteria and definitions. The applicability of each tool and its most sensitive surgical spine population was determined by panel consensus. Bias was assessed using the Newcastle-Ottawa Scale. RESULTS: 47 studies were included in the final qualitative analysis. A total of 14 separate frailty tools were identified, in which 9 tools assessed frailty according to the cumulative deficit definition, while 4 instruments utilized phenotypic or weighted frailty models. One instrument assessed frailty according to the comprehensive geriatric assessment (CGA) model. Twelve measures were validated as risk stratification tools for predicting postoperative AEs, while 1 tool investigated the effect of spine surgery on postoperative frailty trajectory. The modified frailty index (mFI), 5-item mFI, adult spinal deformity frailty index (ASD-FI), FRAIL Scale, and CGA had the most positive ratings for clinimetric properties assessed. CONCLUSIONS: The assessment of frailty is important in the surgical decision-making process. Cumulative deficit and weighted frailty instruments are appropriate risk stratification tools. Phenotypic tools are sensitive for capturing the relationship between spinal pathology, spine surgery, and prehabilitation on frailty trajectory. CGA instruments are appropriate screening tools for identifying health deficits susceptible to improvement and guiding optimization strategies. Studies are needed to determine whether spine surgery and prehabilitation are effective interventions to reverse frailty.