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.

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.

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.

Patient-Reported Outcomes Following Surgery for Lumbar Disc Herniation: Comparison of a Universal and Multitier Health Care System

STUDY DESIGN

Ambispective cohort study.

OBJECTIVE

Canada has a government-funded universal health care system. The United States utilizes a multitier public and private system. The objective is to investigate differences in clinical outcomes between those surgically treated for lumbar disc herniation in a universal health care and multitier health system.

METHODS

Surgical lumbar disc herniation patients enrolled in the Canadian Spine Outcome Research Network (CSORN) were compared with the surgical cohort enrolled in the Spine Patients Outcome Research Trial (SPORT) study. Baseline demographics and spine-related patient-reported outcomes (PROs) were compared at 3 months and 1 year post-operatively.

RESULTS

The CSORN cohort consisted of 443 patients; the SPORT cohort had 763 patients. Patients in the CSORN cohort were older (46.4 ± 13.5 vs 41.0 ± 10.8, P < .001) and were more likely to be employed (69.5% vs 60.3%, P = .003). The CSORN cohort demonstrated significantly greater rates of satisfaction after surgery at 3 months (87.2% vs 64.8%, P < .0001) and 1 year (85.6% vs 69.6%, P < .0001). Improvements in back and leg pain followed similar trajectories in the two cohorts, but there was less improvement on ODI in the CSORN cohort (P < .01). On multivariable logistic regression, the CSORN cohort was a significant independent predictor of patient satisfaction at 1-year follow-up (P < .001).

CONCLUSIONS

Despite less improvement on ODI, patients enrolled in CSORN, as part of a universal health care system, reported higher rates of satisfaction at 3 months and 1 year post-operatively compared to patients enrolled within a multitier health system.

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.

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).

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.

Surgical outcomes of patients who fail to reach minimal clinically important differences: comparison of minimally invasive versus open transforaminal lumbar interbody fusion

OBJECTIVE

Treatment of degenerative lumbar diseases has been shown to be clinically effective with open transforaminal lumbar interbody fusion (O-TLIF) or minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Despite this, a substantial proportion of patients do not meet minimal clinically important differences (MCIDs) in patient-reported outcomes (PROs). The objectives of this study were to compare the proportions of patients who did not meet MCIDs after O-TLIF and MIS-TLIF and to determine potential clinical factors associated with failure to achieve MCID.

METHODS

The authors performed a retrospective analysis of consecutive patients who underwent O-TLIF or MIS-TLIF for lumbar degenerative disorders and had been prospectively enrolled in the Canadian Spine Outcomes and Research Network. The authors analyzed the Oswestry Disability Index (ODI) scores, physical and mental component summary scores of SF-12, numeric rating scale (NRS) scores for leg and back pain, and EQ-5D scores of the patients in each group who did not meet the MCID of ODI at 2 years postoperatively.

RESULTS

In this study, 38.8% (137 of 353) of patients in the O-TLIF cohort and 41.8% (51 of 122) of patients in the MIS-TLIF cohort did not meet the MCID of ODI at 2 years postoperatively (p = 0.59). Demographic variables and baseline PROs were similar between groups. There were improvements across the PROs of both groups through 2 years, and there were no differences in any PROs between the O-TLIF and MIS-TLIF cohorts. Multivariable logistic regression analysis demonstrated that higher baseline leg pain score (p = 0.017) and a diagnosis of spondylolisthesis (p = 0.0053) or degenerative disc disease (p = 0.022) were associated with achieving the MCID at 2 years after O-TLIF, whereas higher baseline leg pain score was associated with reaching the MCID after MIS-TLIF (p = 0.038).

CONCLUSIONS

Similar proportions of patients failed to reach the MCID of ODI at 2 years after O-TLIF or MIS-TLIF. Higher baseline leg pain score was predictive of achieving the MCID in both cohorts, whereas a diagnosis of spondylolisthesis or degenerative disc disease was predictive of reaching the MCID after O-TLIF. These data provide novel insights for patient counseling and suggest that either MIS-TLIF or O-TLIF does not overcome specific patient factors to mitigate clinical success or failure in terms of the intermediate-term PROs associated with 1- to 2-level lumbar fusion surgical procedures for degenerative pathologies.

Development of a machine learning algorithm for predicting in-hospital and 1-year mortality after traumatic spinal cord injury

BACKGROUND CONTEXT

Current prognostic tools such as the Injury Severity Score (ISS) that predict mortality following trauma do not adequately consider the unique characteristics of traumatic spinal cord injury (tSCI).

PURPOSE

Our aim was to develop and validate a prognostic tool that can predict mortality following tSCI.

STUDY DESIGN

Retrospective review of a prospective cohort study.

PATIENT SAMPLE

Data was collected from 1245 persons with acute tSCI who were enrolled in the Rick Hansen Spinal Cord Injury Registry between 2004 and 2016.

OUTCOME MEASURES

In-hospital and 1-year mortality following tSCI.

METHODS

Machine learning techniques were used on patient-level data (n=849) to develop the Spinal Cord Injury Risk Score (SCIRS) that can predict mortality based on age, neurological level and completeness of injury, AOSpine classification of spinal column injury morphology, and Abbreviated Injury Scale scores. Validation of the SCIRS was performed by testing its accuracy in an independent validation cohort (n=396) and comparing its performance to the ISS, a measure which is used to predict mortality following general trauma.

RESULTS

For 1-year mortality prediction, the values for the Area Under the Receiver Operating Characteristic Curve (AUC) for the development cohort were 0.84 (standard deviation=0.029) for the SCIRS and 0.55 (0.041) for the ISS. For the validation cohort, AUC values were 0.86 (0.051) for the SCIRS and 0.71 (0.074) for the ISS. For in-hospital mortality, AUC values for the development cohort were 0.87 (0.028) and 0.60 (0.050) for the SCIRS and ISS, respectively. For the validation cohort, AUC values were 0.85 (0.054) for the SCIRS and 0.70 (0.079) for the ISS.

CONCLUSIONS

The SCIRS can predict in-hospital and 1-year mortality following tSCI more accurately than the ISS. The SCIRS can be used in research to reduce bias in estimating parameters and can help adjust for coefficients during model development. Further validation using larger sample sizes and independent datasets is needed to assess its reliability and to evaluate using it as an assessment tool to guide clinical decision-making and discussions with patients and families.

Time to return to work after elective lumbar spine surgery

OBJECTIVE

Time to return to work (RTW) after elective lumbar spine surgery is variable and dependent on many factors including patient, work-related, and surgical factors. The primary objective of this study was to describe the time and rate of RTW after elective lumbar spine surgery. Secondary objectives were to determine predictors of early RTW (< 90 days) and no RTW in this population.

METHODS

A retrospective analysis of prospectively collected data from the multicenter Canadian Spine Outcomes and Research Network (CSORN) surgical registry was performed to identify patients who were employed and underwent elective 1- or 2-level discectomy, laminectomy, and/or fusion procedures between January 2015 and December 2019. The percentage of patients who returned to work and the time to RTW postoperatively were calculated. Predictors of early RTW and not returning to work were determined using a multivariable Cox regression model and a multivariable logistic regression model, respectively.

RESULTS

Of the 1805 employed patients included in this analysis, 71% returned to work at a median of 61 days. The median RTW after a discectomy, laminectomy, or fusion procedure was 51, 46, and 90 days, respectively. Predictors of early RTW included male gender, higher education level (high school or above), higher preoperative Physical Component Summary score, working preoperatively, a nonfusion procedure, and surgery in a western Canadian province (p < 0.05). Patients who were working preoperatively were twice as likely to RTW within 90 days (HR 1.984, 95% CI 1.680-2.344, p < 0.001) than those who were employed but not working. Predictors of not returning to work included symptoms lasting more than 2 years, an increased number of comorbidities, an education level below high school, and an active workers' compensation claim (p < 0.05). There were fourfold odds of not returning to work for patients who had not been working preoperatively (OR 4.076, 95% CI 3.087-5.383, p < 0.001).

CONCLUSIONS

In the Canadian population, 71% of a preoperatively employed segment returned to work after 1- or 2-level lumbar spine surgery. Most patients who undergo a nonfusion procedure RTW after 6 to 8 weeks, whereas patients undergoing a fusion procedure RTW at 12 weeks. Working preoperatively significantly increased the likelihood of early RTW.

National adverse event profile after lumbar spine surgery for lumbar degenerative disorders and comparison of complication rates between hospitals: a CSORN registry study

OBJECTIVE

Previous works investigating rates of adverse events (AEs) in spine surgery have been retrospective, with data collection from administrative databases, and often from single centers. To date, there have been no prospective reports capturing AEs in spine surgery on a national level, with comparison among centers.

METHODS

The Spine Adverse Events Severity system was used to define the incidence and severity of AEs after spine surgery by using data from the Canadian Spine Outcomes and Research Network (CSORN) prospective registry. Patient data were collected prospectively and during hospital admission for those undergoing elective spine surgery for degenerative conditions. The Spine Adverse Events Severity system defined minor and major AEs as grades 1-2 and 3-6, respectively.

RESULTS

There were 3533 patients enrolled in this cohort. There were 85 (2.4%) individual patients with at least one major AE and 680 (19.2%) individual patients with at least one minor AE. There were 25 individual patients with 28 major intraoperative AEs and 260 patients with 275 minor intraoperative AEs. Postoperatively there were 61 patients with a total of 80 major AEs. Of the 487 patients with minor AEs postoperatively there were 698 total AEs. The average enrollment was 321 patients (range 47-1237 patients) per site. The rate of major AEs was consistent among sites (mean 2.9% ± 2.4%, range 0%-9.1%). However, the rate of minor AEs varied widely among sites-from 7.9% to 42.5%, with a mean of 18.8% ± 9.7%. The rate of minor AEs varied depending on how they were reported, with surgeon reporting associated with the lowest rates (p < 0.01).

CONCLUSIONS

The rate of major AEs after lumbar spine surgery is consistent among different sites but the rate of minor AEs appears to vary substantially. The method by which AEs are reported impacts the rate of minor AEs. These data have implications for the detection and reporting of AEs and the design of strategies aimed at mitigating complications.

The impact of frailty on patient-reported outcomes after elective thoracolumbar degenerative spine surgery

OBJECTIVE

Frailty has been shown to be a risk factor of perioperative adverse events (AEs) in patients undergoing various types of spine surgery. However, the relationship between frailty and patient-reported outcomes (PROs) remains unclear. The primary objective of this study was to determine the impact of frailty on PROs of patients who underwent surgery for thoracolumbar degenerative conditions. The secondary objective was to determine the associations among frailty, baseline PROs, and perioperative AEs.

METHODS

This was a retrospective study of a prospective cohort of patients older than 55 years who underwent surgery between 2012 and 2018. Data and PROs (collected with EQ-5D, Physical Component Summary [PCS] and Mental Component Summary [MCS] of SF-12, Oswestry Disability Index [ODI], and numeric rating scales [NRS] for back pain and leg pain) of patients treated at a single academic center were extracted from the Canadian Spine Outcomes and Research Network registry. Frailty was calculated using the modified frailty index (mFI), and patients were classified as frail, prefrail, and nonfrail. A generalized estimating equation (GEE) regression model was used to assess the association between baseline frailty status and PRO measures at 3 and 12 months.

RESULTS

In total, 293 patients with a mean ± SD age of 67 ± 7 years were included. Of these, 22% (n = 65) were frail, 59% (n = 172) were prefrail, and 19% (n = 56) were nonfrail. At baseline, the three frailty groups had similar PROs, except PCS (p = 0.003) and ODI (p = 0.02) were worse in the frail group. A greater proportion of frail patients experienced major AEs than nonfrail patients (p < 0.0001). However, despite the increased incidence of AEs, there was no association between frailty and postoperative PROs (scores on EQ-5D, PCS and MCS, ODI, and back-pain and leg-pain NRS) at 3 and 12 months (p ≥ 0.05). In general, PROs improved at 3 and 12 months (with most patients reaching the minimum clinically important difference for all PROs).

CONCLUSIONS

Although frailty predicted postoperative AEs, mFI did not predict PROs of patients older than 55 years with degenerative thoracolumbar spine after spine surgery.

Characterization of Cerebrospinal Fluid Ubiquitin C-Terminal Hydrolase L1 as a Biomarker of Human Acute Traumatic Spinal Cord Injury

A major obstacle for translational research in acute spinal cord injury (SCI) is the lack of biomarkers that can objectively stratify injury severity and predict outcome. Ubiquitin C-terminal hydrolase L1 (UCH-L1) is a neuron-specific enzyme that shows promise as a diagnostic biomarker in traumatic brain injury (TBI), but has not been studied in SCI. In this study, cerebrospinal fluid (CSF) and serum samples were collected over the first 72-96 h post-injury from 32 acute SCI patients who were followed prospectively to determine neurological outcomes at 6 months post-injury. UCH-L1 concentration was measured using the Quanterix Simoa platform (Quanterix, Billerica, MA) and correlated to injury severity, time, and neurological recovery. We found that CSF UCH-L1 was significantly elevated by 10- to 100-fold over laminectomy controls in an injury severity- and time-dependent manner. Twenty-four-hour post-injury CSF UCH-L1 concentrations distinguished between American Spinal Injury Association Impairment Scale (AIS) A and AIS B, and AIS A and AIS C patients in the acute setting, and predicted who would remain "motor complete" (AIS A/B) at 6 months with a sensitivity of 100% and a specificity of 86%. AIS A patients who did not improve their AIS grade at 6 months post-injury were characterized by sustained elevations in CSF UCH-L1 up to 96 h. Similarly, the failure to gain >8 points on the total motor score at 6 months post-injury was associated with higher 24-h CSF UCH-L1. Unfortunately, serum UCH-L1 levels were not informative about injury severity or outcome. In conclusion, CSF UCH-L1 in acute SCI shows promise as a biomarker to reflect injury severity and predict outcome.

Characterization of Hyperacute Neuropathic Pain after Spinal Cord Injury: A Prospective Study

There is currently a lack of information regarding neuropathic pain in the very early stages of spinal cord injury (SCI). In the present study, neuropathic pain was assessed using the Douleur Neuropathique 4 Questions (DN4) for the patient's worst pain within the first 5 days of injury (i.e., hyperacute) and on follow-up at 3, 6, and 12 months. Within the hyperacute time frame (i.e., 5 days), at- and below-level neuropathic pain were reported as the worst pain in 23% (n = 18) and 5% (n = 4) of individuals with SCI, respectively. Compared to the neuropathic pain observed in this hyperacute setting, late presenting neuropathic pain was characterized by more intense painful electrical and cold sensations, but less itching sensations. Phenotypic differences between acute and late neuropathic pain support the incorporation of timing into a mechanism-based classification of neuropathic pain after SCI. The diagnosis of acute neuropathic pain after SCI is challenged by the presence of nociceptive and neuropathic pains, with the former potentially masking the latter. This may lead to an underestimation of the incidence of neuropathic pain during the very early, hyperacute time points post-injury. TRIAL REGISTRATION: ClinicalTrials.gov (Identifier: NCT01279811) PERSPECTIVE: This article presents distinct pain phenotypes of hyperacute and late presenting neuropathic pain after spinal cord injury and highlights the challenges of pain assessments in the acute phase after injury. This information may be relevant to clinical trial design and broaden our understanding of neuropathic pain mechanisms after spinal cord injury.

Accuracy of hospital-based surveillance systems for surgical site infection after adult spine surgery: A Bayesian latent class analysis

BACKGROUND

Surgical site infections (SSIs) of the spine are morbid and costly complications. An accurate surveillance system is required to properly describe the disease burden and the impact of interventions that mitigate SSI risk. Unfortunately, uniform approaches to conducting SSI surveillance are lacking because of varying SSI case definitions, the lack of a perfect reference case definition and heterogeneous data sources.

AIM

We assessed the accuracy of 4 independent data sources that capture SSIs after spine surgery, with estimation of a measurement error-adjusted SSI incidence.

METHODS

A Bayesian latent class model assessed the sensitivity/specificity of each data source to identify SSI and to estimate a measurement-error adjusted incidence. The four data sources used were: the discharge abstract database (DAD), the National Surgical Quality Improvement Program (NSQIP) database, the Infection Prevention and Control Canada (IPAC) database, and the Spine Adverse Events Severity database.

FINDINGS

A total of 904 patients underwent spine surgery in 2017. The most sensitive data source was DAD (0.799, 95% CrI 0.597, 0.943), while the least sensitive was NSQIP (0.497, 95% CrI 0.308, 0.694). The most specific data source was IPAC (0.997, 95% CrI 0.993, 1.000) and the least specific was DAD (0.969, 95% CrI 0.956, 0.981). The measurement error-adjusted SSI incidence was 0.030 (95% CrI 0.019, 0.045). The crude incidence using the DAD over-estimated the incidence, and the 3 other data sources under-estimated it.

CONCLUSION

SSI surveillance in the spine surgery population is feasible using several data sources, provided that measurement error is considered.

Lumbar degenerative spondylolisthesis: factors associated with the decision to fuse

BACKGROUND CONTEXT

The indication to perform a fusion and decompression surgery as opposed to decompression alone for lumbar degenerative spondylolisthesis (LDS) remains controversial. A variety of factors are considered when deciding on whether to fuse, including patient demographics, radiographic parameters, and symptom presentation. Likely surgeon preference has an important influence as well.

PURPOSE

The aim of this study was to assess factors associated with the decision of a Canadian academic spine surgeon to perform a fusion for LDS.

STUDY DESIGN/SETTING

This study is a retrospective analysis of patients prospectively enrolled in a multicenter Canadian study that was designed to evaluate the assessment and surgical management of LDS.

PATIENT SAMPLE

Inclusion criteria were patients with: radiographic evidence of LDS and neurogenic claudication or radicular pain, undergoing posterior decompression alone or posterior decompression and fusion, performed in one of seven, participating academic centers from 2015 to 2019.

OUTCOME MEASURES

Patient demographics, patient-rated outcome measures (Oswestry Disability Index [ODI], numberical rating scale back pain and leg pain, SF-12), and imaging parameters were recorded in the Canadian Spine Outcomes Research Network (CSORN) database. Surgeon factors were retrieved by survey of each participating surgeon and then linked to their specific patients within the database.

METHODS

Univariate analysis was used to compare patient characteristics, imaging measures, and surgeon variables between those that had a fusion and those that had decompression alone. Multivariate backward logistic regression was used to identify the best combination of factors associated with the decision to perform a fusion.

RESULTS

This study includes 241 consecutively enrolled patients receiving surgery from 11 surgeons at 7 sites. Patients that had a fusion were younger (65.3±8.3 vs. 68.6±9.7 years, p=.012), had worse ODI scores (45.9±14.7 vs. 40.2±13.5, p=.007), a smaller average disc height (6.1±2.7 vs. 8.0±7.3 mm, p=.005), were more likely to have grade II spondylolisthesis (31% vs. 14%, p=.008), facet distraction (34% vs. 60%, p=.034), and a nonlordotic disc angle (26% vs. 17%, p=.038). The rate of fusion varied by individual surgeon and practice location (p<.001, respectively). Surgeons that were fellowship trained in Canada more frequently fused than those who fellowship trained outside of Canada (76% vs. 57%, p=.027). Surgeons on salary fused more frequently than surgeons remunerated by fee-for-service (80% vs. 64%, p=.004). In the multivariate analysis the clinical factors associated with an increased odds of fusion were decreasing age, decreasing disc height, and increasing ODI score; the radiographic factors were grade II spondylolisthesis and neutral or kyphotic standing disc type; and the surgeon factors were fellowship location, renumeration type and practice region. The odds of having a fusion surgery was more than two times greater for patients with a grade II spondylolisthesis or neutral and/or kyphotic standing disc type (opposed to lordotic standing disc type). Patients whose surgeon completed their fellowship in Canada, or whose surgeon was salaried (opposed to fee-for-service), or whose surgeon practiced in western Canada had twice the odds of having fusion surgery.

CONCLUSIONS

The decision to perform a fusion in addition to decompression for LDS is multifactorial. Although patient and radiographic parameters are important in the decision-making process, multiple surgeon factors are associated with the preference of a Canadian spine surgeon to perform a fusion for LDS. Future work is necessary to decrease treatment variability between surgeons and help facilitate the implementation of evidence-based decision making.

The Effect of Perioperative Adverse Events on Long-Term Patient-Reported Outcomes After Lumbar Spine Surgery

BACKGROUND

Perioperative adverse events (AEs) lead to patient disappointment and greater costs. There is a paucity of data on how AEs affect long-term outcomes.

OBJECTIVE

To examine perioperative AEs and their impact on outcome after lumbar spine surgery.

METHODS

A total of 3556 consecutive patients undergoing surgery for lumbar degenerative disorders enrolled in the Canadian Spine Outcomes and Research Network were analyzed. AEs were defined using the validated Spine AdVerse Events Severity system. Outcomes at 3, 12, and 24 mo postoperatively included the Owestry Disability Index (ODI), 12-Item Short-Form Health Survey (SF-12) Physical (PCS) and Mental (MCS) Component Summary scales, visual analog scale (VAS) leg and back, EuroQol-5D (EQ5D), and satisfaction.

RESULTS

AEs occurred in 767 (21.6%) patients, and 85 (2.4%) patients suffered major AEs. Patients with major AEs had worse ODI scores and did not reach minimum clinically important differences at 2 yr (no AE: 25.7 ± 19.2, major: 36.4 ± 19.1, P < .001). Major AEs were associated with worse ODI scores on multivariable linear regression (P = .011). PCS scores were lower after major AEs (43.8 ± 9.5, vs 37.7 ± 20.3, P = .002). On VAS leg and back and EQ5D, the 2-yr outcomes were significantly different between the major and no AE groups (<0.01), but these differences were small (VAS leg: 3.4 ± 3.0 vs 4.0 ± 3.3; VAS back: 3.5 ± 2.7 vs 4.5 ± 2.6; EQ5D: 0.75 ± 0.2 vs 0.64 ± 0.2). SF12 MCS scores were not different. Rates of satisfaction were lower after major AEs (no AE: 84.6%, major: 72.3%, P < .05).

CONCLUSION

Major AEs after lumbar spine surgery lead to worse functional outcomes and lower satisfaction. This highlights the need to implement strategies aimed at reducing AEs.

Effectiveness of silver alloy-coated silicone urinary catheters in patients with acute traumatic cervical spinal cord injury: Results of a quality improvement initiative

Patients with acute traumatic cervical spinal cord injury (ATCSCI) have an increased risk of catheter-associated urinary tract infection (CAUTI). The effectiveness of silver alloy-coated silicone urinary catheters (SACC) in preventing CAUTI in ATCSCI is unknown and was the objective of this study. We performed a quality improvement initiative in an attempt to reduce CAUTI in patients undergoing spine surgery at a single quaternary center. Prior to July 2015, all patients received a latex indwelling catheter (LIC). All patients with ATCSCI with limited hand function (AIS A,B, or C) received a SACC. Incidence of CAUTI, microbiology, duration of infection, antibiotic susceptibility, and catheter-associated adverse events were recorded prospectively. We studied 3081 consecutive patients over the three years, of whom 302 (9.8%) had ATCSCI; 63% of ATCSCI patients were ASIA Impairment Scale (AIS) A or B. The overall rate of CAUTI was 19% (585/3081), and was 38% (116/302) in patients with ATCSCI. Of 178 ATCSCI patients with LIC, 100 (56%) developed a CAUTI compared with 28 of 124 (23%) patients with SACC (p < 0.05). Poly-microbial and gram-positive infection was more common in LIC than in SACC (p < 0.05). Median duration of infection was 9 days in SACC group and 12 days in LIC group (p = 0.08). Resistance to trimethoprim (p < 0.001) and ciprofloxacin (p < 0.05) were more common in LIC group. There was no difference in catheter-associated adverse events or length of stay between the groups. This quality improvement initiative illustrates the effectiveness of antiseptic silver alloy-coated silicone urinary catheters in patients with ATCSCI. In our population, the use of SACC reduces the incidence and the complexity of CAUTI.

Sarcopenia, but not frailty, predicts early mortality and adverse events after emergent surgery for metastatic disease of the spine

BACKGROUND CONTEXT

Frailty and sarcopenia variably predict adverse events (AEs) in a number of surgical populations.

PURPOSE

The aim of this study was to investigate the ability of frailty and sarcopenia to independently predict early mortality and AEs following urgent surgery for metastatic disease of the spine.

STUDY DESIGN

A single institution, retrospective cohort study.

PATIENT SAMPLE

One hundred eight patients undergoing urgent surgery for spinal metastases from 2009 to 2015.

OUTCOME MEASURES

The incidence of AEs including 1- and 3-month mortality.

METHODS

Sarcopenia was defined using the L3 Total Psoas Area/Vertebral body Area (L3-TPA/VB) technique on CT. The modified Frailty Index (mFI), Metastatic Frailty Index (MSTFI) and the Bollen prognostic scales were calculated for each patient. Additional data included demographics, tumor type and burden, neurological status, the extent of surgical treatment and the use of radiation-therapy. Spearman correlation test, logistic regression and Kaplan-Meier were used to study the relation between the outcomes measures and potential predictors (L3-TPA/VB, MSTFI, mFI, and the Bollen prognostic scales).

RESULTS

Eighty-five percent of patients had at least one acute AE. Sarcopenia predicted the occurrence of at least one postop AE (L3-TPA/VB, 1.07±0.40 vs. 1.25±0.52; p=.031). Sarcopenia (L3-TPA/VB) and the degree of neurological impairment were predictive of postoperative AE but MFI or MSTFI were not. Sarcopenia predicted 3-month mortality, independent of primary tumor type (L3-TPA/VB: 0.86±0.27 vs. 1.12±0.41; p<.001). Kaplan-Meyer analysis showed L3-TPA/VB and the Bollen Scale to significantly discriminate patient survival.

CONCLUSIONS

Sarcopenia, easily measured by the L3-TPA/VB on conventional CT, predicts both early postoperative mortality and adverse events in patients undergoing urgent surgery for spinal metastasis, thus providing a practical tool for timely therapeutic decision-making in this complex patient population.

Perioperative adverse events following surgery for primary bone tumors of the spine and en bloc resection for metastases

OBJECTIVE

Surgical treatment of primary bone tumors of the spine and en bloc resection for isolated metastases are complex and challenging. Operative care is fraught with complications, though the true incidence and predictors of adverse events (AEs), length of stay (LOS), and mortality in this population remain poorly understood. The primary objective of this study was to describe the incidence and predictors of perioperative AEs in these patients. Secondary objectives included the determination of the incidence and predictors of admission to the intensive care unit (ICU), unanticipated reoperation during the same admission, hospital LOS, and mortality.

METHODS

In this retrospective analysis of prospectively collected data, the authors included consecutive patients at a single quaternary care referral center (January 1, 2009, to September 30, 2018) who underwent either surgery for a primary bone tumor of the spine or an en bloc resection for an isolated spinal metastasis. Information on perioperative AEs, demographic data, primary tumor histology, neurological status, surgical variables, pathological margins, Enneking appropriateness, LOS, ICU stay, reoperation during the same admission period, and in-hospital mortality was collected prospectively in the institutional database. The modified frailty score was extracted retrospectively.

RESULTS

One hundred thirteen patients met the inclusion criteria: 98 with primary bone tumors and 15 with isolated metastases. The cohort was 59% male, and the mean age was 49 years (SD 19 years). Overall, 79% of the patients experienced at least 1 AE. The median number of AEs per patient was 2 (IQR 0-4 AEs), and the median LOS was 16 days (IQR 9-32 days). No in-hospital deaths occurred in the cohort. Thirty-two patients (28%) required an ICU stay and 19% underwent an unanticipated second surgery during their admission. A longer surgical duration was associated with a higher likelihood of AEs (OR 1.21/hour, 95% CI 1.06-1.37, p = 0.005), longer ICU stay (OR 1.35/hour, 95% CI 1 1.20-1.52, p < 0.001), and reoperation (OR 1.001/hour, 95% CI 1.0003-1.003, p = 0.012). Longer hospital LOS was independently predicted by older age, female sex, upper cervical and sacral location of the tumor, surgical duration, preoperative neurological deficit, presence of AEs, and higher modified frailty index score.

CONCLUSIONS

Surgeries for primary bone tumors and en bloc resection for metastatic tumors are associated with a high incidence of perioperative AEs. Surgical duration predicts complications, reoperation, LOS, and ICU stay.

Development and Validation of a Novel Adult Spinal Deformity Surgical Invasiveness Score: Analysis of 464 Patients

BACKGROUND

A surgical invasiveness index (SII) has been validated in general spine procedures but not adult spinal deformity (ASD).

OBJECTIVE

To assess the ability of the SII to determine the invasiveness of ASD surgery and to create and validate a novel ASD index incorporating deformity-specific factors, which could serve as a standardized metric to compare outcomes and risk stratification of different ASD procedures for a given deformity.

METHODS

Four hundred sixty-four patients who underwent ASD surgery between 2009 and 2012 were identified in 2 multicenter prospective registries. Multivariable models of estimated blood loss (EBL) and operative time were created using deformity-specific factors. Beta coefficients derived from these models were used to attribute points to each component. Scoring was iteratively refined to determine the R2 value of multivariate models of EBL and operative time using adult spinal deformity-surgical (ASD-S) as an independent variable. Similarly, we determined weighting of postoperative changes in radiographical parameters, which were incorporated into another index (adult spinal deformity-surgical and radiographical [ASD-SR]). The ability of these models to predict surgical invasiveness was assessed in a validation cohort.

RESULTS

Each index was a significant, independent predictor of EBL and operative time (P < .001). On multivariate analysis, ASD-S and ASD-SR explained more variability in EBL and operative time than did the SII (P < .001). The ASD-SR explained 21% of the variation in EBL and 10% of the variation in operative time, whereas the SII explained 17% and 3.2%, respectively.

CONCLUSION

The ASD-SR, which incorporates deformity-specific components, more accurately predicts the magnitude of ASD surgery than does the SII.

Empirical targets for acute hemodynamic management of individuals with spinal cord injury

OBJECTIVE

To determine the hemodynamic conditions associated with optimal neurologic improvement in individuals with acute traumatic spinal cord injury (SCI) who had lumbar intrathecal catheters placed to measure CSF pressure (CSFP).

METHODS

Ninety-two individuals with acute SCI were enrolled in this multicenter prospective observational clinical trial. We monitored mean arterial pressure (MAP) and CSFP during the first week after injury and assessed neurologic function at baseline and 6 months after injury. We used relative risk iterations to determine transition points at which the likelihood of either improving neurologically or remaining unchanged neurologically was equivalent. These transition points guided our analyses in which we examined the linear relationships between time spent within target hemodynamic ranges (i.e., clinical adherence) and neurologic recovery.

RESULTS

Relative risk transition points for CSFP, MAP, and spinal cord perfusion pressure (SCPP) were linearly associated with neurologic improvement and directed the identification of key hemodynamic target ranges. Clinical adherence to the target ranges was positively and linearly related to improved neurologic outcomes. Adherence to SCPP targets, not MAP targets, was the best indicator of improved neurologic recovery, which occurred with SCPP targets of 60 to 65 mm Hg. Failing to maintain the SCPP within the target ranges was an important detrimental factor in neurologic recovery, particularly if the target range is set lower.

CONCLUSION

We provide an empirical, data-driven approach to aid institutions in setting hemodynamic management targets that accept the real-life challenges of adherence to specific targets. Our results provide a framework to guide the development of widespread institutional management guidelines for acute traumatic SCI.

Decision tree analysis to better control treatment effects in spinal cord injury clinical research

OBJECTIVE

The aim of this study was to use decision tree modeling to identify optimal stratification groups considering both the neurological impairment and spinal column injury and to investigate the change in motor score as an example of a practical application. Inherent heterogeneity in spinal cord injury (SCI) introduces variation in natural recovery, compromising the ability to identify true treatment effects in clinical research. Optimized stratification factors to create homogeneous groups of participants would improve accurate identification of true treatment effects.

METHODS

The analysis cohort consisted of patients with acute traumatic SCI registered in the Vancouver Rick Hansen Spinal Cord Injury Registry (RHSCIR) between 2004 and 2014. Severity of neurological injury (American Spinal Injury Association Impairment Scale [AIS grades A-D]), level of injury (cervical, thoracic), and total motor score (TMS) were assessed using the International Standards for Neurological Classification of Spinal Cord Injury examination; morphological injury to the spinal column assessed using the AOSpine classification (AOSC types A-C, C most severe) and age were also included. Decision trees were used to determine the most homogeneous groupings of participants based on TMS at admission and discharge from in-hospital care.

RESULTS

The analysis cohort included 806 participants; 79.3% were male, and the mean age was 46.7 ± 19.9 years. Distribution of severity of neurological injury at admission was AIS grade A in 40.0% of patients, grade B in 11.3%, grade C in 18.9%, and grade D in 29.9%. The level of injury was cervical in 68.7% of patients and thoracolumbar in 31.3%. An AOSC type A injury was found in 33.1% of patients, type B in 25.6%, and type C in 37.8%. Decision tree analysis identified 6 optimal stratification groups for assessing TMS: 1) AOSC type A or B, cervical injury, and age ≤ 32 years; 2) AOSC type A or B, cervical injury, and age > 32-53 years; 3) AOSC type A or B, cervical injury, and age > 53 years; 4) AOSC type A or B and thoracic injury; 5) AOSC type C and cervical injury; and 6) AOSC type C and thoracic injury.

CONCLUSIONS

Appropriate stratification factors are fundamental to accurately identify treatment effects. Inclusion of AOSC type improves stratification, and use of the 6 stratification groups could minimize confounding effects of variable neurological recovery so that effective treatments can be identified.

MicroRNA Biomarkers in Cerebrospinal Fluid and Serum Reflect Injury Severity in Human Acute Traumatic Spinal Cord Injury

Spinal cord injury (SCI) is a devastating condition with variability in injury mechanisms and neurologic recovery. Spinal cord impairment after SCI is measured and classified by a widely accepted standard neurological examination. In the very acute stages post-injury, however, this examination is extremely challenging (and often impossible) to conduct and has modest prognostic value in terms of neurological recovery. The lack of objective tools to classify injury severity and predict outcome is a barrier for clinical trials and thwarts development of therapies for those with SCI. Biological markers (biomarkers) represent a promising, complementary approach to these challenges because they represent an unbiased approach to classify injury severity and predict neurological outcome. Identification of a suitable panel of molecular biomarkers would comprise a fundamental shift in how patients with acute SCI are evaluated, stratified, and treated in clinical trials. MicroRNA are attractive biomarker candidates in neurological disorders for several reasons, including their stability in biological fluids, their conservation between humans and model mammals, and their tissue specificity. In this study, we used next-generation sequencing to identify microRNA associated with injury severity within the cerebrospinal fluid (CSF) and serum of human patients with acute SCI. The CSF and serum samples were obtained 1-5 days post-injury from 39 patients with acute SCI (24 American Spinal Injury Association Impairment Scale [AIS] A, 8 AIS B, 7 AIS C) and from five non-SCI controls. We identified a severity-dependent pattern of change in microRNA expression in CSF and identified a set of microRNA that are diagnostic of baseline AIS classification and prognostic of neurological outcome six months post-injury. The data presented here provide a comprehensive description of the CSF and serum microRNA expression changes that occur after acute human SCI. This data set reveals microRNA candidates that warrant further evaluation as biomarkers of injury severity after SCI and as key regulators in other neurological disorders.

Clinical outcomes research in spine surgery: what are appropriate follow-up times?

OBJECTIVE

There has been a generic dictum in spine and musculoskeletal clinical research that a minimum 2-year follow-up is necessary for patient-reported outcomes (PROs) to adequately assess the therapeutic effect of surgery; however, the rationale for this duration is not evidence based. The purpose of this study was to determine the follow-up time necessary to ensure that the effectiveness of a lumbar surgical intervention is adequately captured for three lumbar pathologies and three common PROs.

METHODS

Using the different PROs of pain, physical function, and mental quality of life from the Canadian Spine Outcomes and Research Network (CSORN) prospective database, the authors assessed the time course to the recovery plateau following lumbar spine surgery for lumbar disc herniation, degenerative spondylolisthesis, and spinal stenosis. One-way ANOVA with post hoc testing was used to compare scores on the following standardized PRO measures at baseline and 3, 12, and 24 months postoperatively: Disability Scale (DS), visual analog scale (VAS) for leg and back pain, and SF-12 Mental Component Summary (MCS) and Physical Component Summary (PCS).

RESULTS

Significant differences for all spine pathologies and specific PROs were found with one-way ANOVA (p < 0.0001). The time to plateaued recovery after surgery for lumbar disc herniation (661 patients), lumbar stenosis (913 patients), and lumbar spondylolisthesis (563 patients) followed the same course for the following PRO measures: VAS for back and leg pain, 3 months; DS, 12 months; PCS, 12 months; and MCS, 3 months. Beyond these time points, no further significant improvements in PROs were seen. Patients with degenerative spondylolisthesis or spinal stenosis who had undergone fusion surgery plateaued at 12 months on the DS and PCS, compared to 3 months in those who had not undergone fusion.

CONCLUSIONS

Specific health dimensions follow distinctly different recovery plateaus, indicating that a 2-year postoperative follow-up is not required for all PROs to accurately assess the treatment effect of lumbar spinal surgery. Ultimately, the clinical research question should dictate the follow-up time and the outcome measure utilized; however, there is now evidence to guide the specific duration of follow-up for pain, physical function, and mental quality of life dimensions.

Patient-reported outcomes following surgery for degenerative spondylolitshtesis: comparison of a universal and multitier health care system

STUDY DESIGN

Retrospective review of results from a prospectively collected Canadian cohort in comparison to published literature.

OBJECTIVES

(1) To investigate whether patients in a universal health care system have different outcomes than those in a multitier health care system in surgical management of degenerative spondylolisthesis (DS). (2) To identify independent factors predictive of outcome in surgical DS patients.

SUMMARY OF BACKGROUND DATA

Canada has a national health insurance program with unique properties. It is a single-payer system, coverage is universal, and access to specialist care requires referral by the primary care physician. The United States on the other hand is a multitier public/private payer system with more rapid access for insured patients to specialist care.

METHODS

Surgical DS patients treated between 2013 and 2016 in Canada were identified through the Canadian Spine Outcome Research Network (CSORN) database, a national registry that prospectively enrolls consecutive patients with spinal pathology from 16 tertiary care academic hospitals. This population was compared with the surgical DS arm of patients treated in the Spine Patients Outcome Research Trial (SPORT) study. We compared baseline demographics, spine-related, and health-related quality of life (HRQOL) outcomes at 3 months and 1 year. Multivariate analysis was used to identify factors predictive of outcome in surgical DS patients.

RESULTS

The CSORN cohort of 213 patients was compared with the SPORT cohort of 248 patients. Patients in the CSORN cohort were younger (mean age 60.1 vs. 65.2; p<.001), comprised fewer females (60.1% vs. 67.7%; p=.09), and had a higher proportion of smokers (23.3% vs. 8.9%; p<.001). The SPORT cohort had more patients receiving compensation (14.6% vs. 7.7%; p<.001). The CSORN cohort consisted of patients with slightly greater baseline disability (Oswestry disability index scores: 47.7 vs. 44.0; p=.008) and had more patients with symptom duration of greater than 6 months (93.7% vs. 62.1%; p<.001). The CSORN cohort showed greater satisfaction with surgical results at 3 months (91.1% vs. 66.1% somewhat or very satisfied; p<.01) and 1 year (88.2% vs. 71.0%, p<.01). Improvements in back and leg pain were similar comparing the two cohorts. On multivariate analysis, duration of symptoms, treatment group (CSORN vs. SPORT) or insurance type (public/Medicare/Medicaid vs. Private/Employer) predicted higher level of postoperative satisfaction. Baseline depression was also associated with worse Oswestry disability index at 1-year postoperative follow-up in both cohorts.

CONCLUSIONS

Surgical DS patients treated in Canada (CSORN cohort) reported higher levels of satisfaction than those treated in the United States (SPORT cohort) despite similar to slightly worse baseline HRQOL measures. Symptom duration and insurance type appeared to impact satisfaction levels. Improvements in other patient-reported health-related quality of life measures were similar between the cohorts.

Patients with Adult Spinal Deformity with Previous Fusions Have an Equal Chance of Reaching Substantial Clinical Benefit Thresholds in Health-Related Quality of Life Measures but Do Not Reach the Same Absolute Level of Improvement

BACKGROUND

Substantial clinical benefit (SCB) represents a threshold above which patients recognize substantial improvement and represents a rational target for defining clinical success. In adult spinal deformity (ASD) surgery, previous fusions may impact outcomes after deformity correction.

OBJECTIVE

To investigate the impact of previous spinal fusion on the likelihood of reaching SCB thresholds for 2-year health-related quality of life (HRQOL) after ASD surgery.

METHODS

We conducted a retrospective review comparing baseline demographic, HRQOL, and radiographic features for patients with ASD undergoing primary versus revision procedures. The primary outcome measure was reaching SCB threshold in Oswestry Disability Index (ODI), SF-36 Physical Component Summary (PCS), and back and leg pain (numeric rating scale). Secondary outcomes included absolute and change scores in ODI, PCS, and back and leg pain.

RESULTS

In total, 332 patients achieved 2-year follow-up (228 primary; 104 revision cases). Those undergoing revision surgery had similar demographic features (age 58.3/55.9, female 80.8%/82.9%) to patients undergoing primary surgery. They had worse baseline HRQOL (ODI 48.5/41.2, PCS 29.5/33.4, back 7.5/7.0, and leg pain 4.9/4.3; P < 0.001) and radiographic deformity (sagittal vertical axis 111.4/45.1, lumbopelvic mismatch 26.7/11.0, pelvic tilt 29.5/21.0; P < 0.0001). Nevertheless, the number of patients who reached SCB for ODI (38.3/36.3%), PCS (48.5/53.4%), back (53.1/60.5%), and leg pain numeric rating scale (28.6/36.9%) did not significantly differ. Revision patients had worse 2-year HRQOL for all measures.

CONCLUSIONS

Patients undergoing revision surgery have worse baseline HRQOL and deformity. Although they do not achieve the same absolute level of 2-year HRQOL outcome, they have a similar likelihood of reaching SCB threshold for improvement in 2-year HRQOL.

Radiographic Fusion Grade Does Not Impact Health-Related Quality of Life in the Absence of Instrumentation Failure for Patients Undergoing Posterior Instrumented Fusion for Adult Spinal Deformity

BACKGROUND

Pseudarthrosis and rod fracture (RF) remain significant concerns after fusion for adult spinal deformity (ASD). Although a radiographic system of fusion grade has been proposed, the correlation between fusion grade and health-related quality of life measures (HRQoL) is not known.

METHODS

In a retrospective review of a prospectively collected clinical database, patients that underwent ≥5-level posterior instrumented arthrodesis for ASD were evaluated. Fusion grade was determined on plain films using the Lenke criteria. Patients were grouped as 1) complete fusion (grade I or II at all levels), 2) incomplete fusion (grade 3 or 4 at any level), 3) rod fracture without revision (RF), and 4) rod fracture with revision (RFR). Outcome measures were the Oswestry Disability Index, Medical Outcomes Study 36-Item Short-Form Health Survey Physical and Mental Component Summaries, Scoliosis Research Society-22r total, and Lumbar Stiffness and Disability Index.

RESULTS

There were 205 (85%) patients who achieved the minimum 2-year follow-up and were included. Complete fusion was achieved in 115 patients (56.1%), 55% patients (26.8%) had incomplete fusion, and 35% patients (17.1%) had RF. Of the 35 patients with RF, 19 (17.1%; 19/205) underwent revision while 16 (7.8%; 16/205) had RF without revision. HRQoL measures were significantly worse in the RFR group, whereas no significant differences were found between groups 1, 2, and 3.

CONCLUSIONS

Radiographic fusion grade after ASD surgery did not significantly impact HRQoL in the absence of RF. RFR was associated with significantly worse clinical outcomes. Fusion grade may be less predictive of clinical outcomes than the occurrence of RF.

Frailty and sarcopenia do not predict adverse events in an elderly population undergoing non-complex primary elective surgery for degenerative conditions of the lumbar spine

BACKGROUND CONTEXT

Sarcopenia measured by normalized total psoas area (NTPA) has been shown to predict mortality and adverse events (AEs) in numerous surgical populations. The relationship between sarcopenia and postoperative outcomes after surgery for degenerative spine disease (DSD) has not been investigated.

PURPOSE

This study aimed to determine the relationships between sarcopenia, frailty, and postoperative AEs in the elderly DSD population. Secondary objectives were to describe the distribution and predictors of NTPA and to determine the relationship between sarcopenia, frailty, and length of stay, discharge to a facility, and in-hospital mortality.

STUDY DESIGN

This is an ambispective study from a quaternary care academic center.

PATIENT SAMPLE

A total of 102 patients over 65 years old who underwent elective thoracolumbar surgery for DSD between 2009 and 2013 were included in this study.

OUTCOME MEASURES

The primary outcome was a composite of perioperative AEs; the secondary outcomes were length of stay, discharge disposition, and in-hospital mortality.

METHODS

Total psoas area (TPA) at mid-L3 level on preoperative computed tomography scan adjusted for height (NTPA) defined sarcopenia. The modified frailty index (mFI) of 11 clinical variables defined frailty. The distribution and predictors of sarcopenia (NTPA) were determined. The association of NTPA with AEs, length of stay, discharge disposition to care facility, and mortality was analyzed, including adjusting for known and suspected confounders using multivariate regression.

RESULTS

Median Spine Surgical Invasiveness Index was 8 (interquartile range 2-10), and mean NTPA was 674 mm²/m² (293.21-1636.25). Using the mFI, 20.6% were pre-frail and 19.6% were frail. Inter- and intraobserver reliability for determining NTPA were near perfect with kappa 0.95-0.97 and 0.94-1.00, respectively. The NTPA was independently associated with patient gender and body mass index (BMI) but not frailty (mFI). Age, BMI, mFI, and American Anesthesiologists' Society score were not associated with incidence of postoperative AEs. The NTPA did not predict the occurrence of AE (odds ratio [OR] 1.06 per 100 mm²/m², 95% confidence interval [CI] 0.91-1.23, p=.45). Similarly, NTPA was not predictive of length of stay (rho=-0.04, p=.67), discharge home (OR 0.95 (95% CI 0.76-1.20) per 100 mm²/m², p=.70), or death (OR 1.12 (95% CI 0.83-1.53) per 100 mm²/m², p=.47). In contrast, increasing mFI was associated with increased risk of mortality (OR 3.12 (95% CI 1.21-8.03) per 0.1 increase in frailty score, p=.006).

CONCLUSIONS

In contrast to other surgical groups, sarcopenia (NTPA) or frailty (mFI) did not predict acute care complications in a selected population of elderly patients undergoing simple lumbar spine surgery for DSD. Although NTPA can be reliably measured in this population, it may be an inappropriate surrogate for sarcopenia given its anatomical relationship to spinal function.

An assessment of frailty as a tool for risk stratification in adult spinal deformity surgery

OBJECTIVE

The goal of this study was to analyze the value of an adult spinal deformity frailty index (ASD-FI) in preoperative risk stratification. Preoperative risk assessment is imperative before procedures known to have high complication rates, such as ASD surgery. Frailty has been associated with risk of complications in trauma surgery, and preoperative frailty assessments could improve the accuracy of risk stratification by providing a comprehensive analysis of patient factors that contribute to an increased risk of complications.

METHODS

Using 40 variables, the authors calculated frailty scores with a validated method for 417 patients (enrolled between 2010 and 2014) with a minimum 2-year follow-up in an ASD database. On the basis of these scores, the authors categorized patients as not frail (NF) (< 0.3 points), frail (0.3–0.5 points), or severely frail (SF) (> 0.5 points). The correlation between frailty category and incidence of complications was analyzed.

RESULTS

The overall mean ASD-FI score was 0.33 (range 0.0–0.8). Compared with NF patients (n = 183), frail patients (n = 158) and SF patients (n = 109) had longer mean hospital stays (1.2 and 1.6 times longer, respectively; p < 0.001). The adjusted odds of experiencing a major intraoperative or postoperative complication were higher for frail patients (OR 2.8) and SF patients ( 4.1) compared with NF patients (p < 0.01). For frail and SF patients, respectively, the adjusted odds of developing proximal junctional kyphosis (OR 2.8 and 3.1) were higher than those for NF patients. The SF patients had higher odds of developing pseudarthrosis (OR 13.0), deep wound infection (OR 8.0), and wound dehiscence (OR 13.4) than NF patients (p < 0.05), and they had 2.1 times greater odds of reoperation (p < 0.05).

CONCLUSIONS

Greater patient frailty, as measured by the ASD-FI, was associated with worse outcome in many common quality and value metrics, including greater risk of major complications, proximal junctional kyphosis, pseudarthrosis, deep wound infection, wound dehiscence, reoperation, and longer hospital stay.

Spinal cord perfusion pressure predicts neurologic recovery in acute spinal cord injury

OBJECTIVE

To determine whether spinal cord perfusion pressure (SCPP) as measured with a lumbar intrathecal catheter is a more predictive measure of neurologic outcome than the conventionally measured mean arterial pressure (MAP).

METHODS

A total of 92 individuals with acute spinal cord injury were enrolled in this multicenter prospective observational clinical trial. MAP and CSF pressure (CSFP) were monitored during the first week postinjury. Neurologic impairment was assessed at baseline and at 6 months postinjury. We used logistic regression, systematic iterations of relative risk, and Cox proportional hazard models to examine hemodynamic patterns commensurate with neurologic outcome.

RESULTS

We found that SCPP (odds ratio 1.039, p = 0.002) is independently associated with positive neurologic recovery. The relative risk for not recovering neurologic function continually increased as individuals were exposed to SCPP below 50 mm Hg. Individuals who improved in neurologic grade dropped below SCPP of 50 mm Hg fewer times than those who did not improve (p = 0.012). This effect was not observed for MAP or CSFP. Those who were exposed to SCPP below 50 mm Hg were less likely to improve from their baseline neurologic impairment grade (p = 0.0056).

CONCLUSIONS

We demonstrate that maintaining SCPP above 50 mm Hg is a strong predictor of improved neurologic recovery following spinal cord injury. This suggests that SCPP (the difference between MAP and CSFP) can provide useful information to guide the hemodynamic management of patients with acute spinal cord injury.

The Fate of Patients with Adult Spinal Deformity Incurring Rod Fracture After Thoracolumbar Fusion

OBJECTIVE

To report the outcome of adult spinal deformity (ASD) in patients with rod fracture (RF) after thoracolumbar fusion.

METHODS

Retrospective review of prospective, multicenter database. Operative patients with ASD ≥18 years old with RF after ASD surgery and with a minimum 6-month follow-up after RF were included. Health-related quality of life scores and radiographic alignment were compared with nonparametric paired and independent testing (P < 0.05).

RESULTS

A total of 51 of 343 patients with ASD (14.9%) sustained a RF, of whom 44 (86.3%) had at least 6-month follow up after RF (mean age = 61.2 years, mean body mass index = 29.6 kg/m²). Mean total follow-up was 37.8 months (range 24.5-66.7 months). Interbody fusion was used in 26 cases of RF (59.1%) (transforaminal lumbar interbody fusion, n = 17 [65.4%], anterior lumbar interbody fusion, n = 5 [19.2%]). RF was symptomatic in 26 of 44 (59.1%) of patients and discovered incidentally in 18 of 44 patients (40.9%). Overall, 28 RFs were revised (63.6%); 12 of 23 (52.2%) unilateral RF and 16 of 21 (76.2%) bilateral RF at last follow-up. Revision patients were significantly more likely to be symptomatic at the time of RF detection (78.6% vs. 25.0%, P = 0.0006), and had significantly worse Oswestry Disability Index and Scoliosis Research Society-22r pain scores.

CONCLUSIONS

RFs were detected in 14.9% of patients with ASD and were most common at the L4-L5 and L5-S1 levels. Approximately 63.6% of patients underwent revision surgery. The decision to perform revision surgery may be based predominantly on symptoms referable to the RF, pain, and perceived disability, as radiographic parameters at the time of RF did not differ significantly between patients who did and did not undergo revision.

The role of revision surgery and adjuvant therapy following subtotal resection of osteosarcoma of the spine: a systematic review with meta-analysis

OBJECTIVE Primary osteosarcoma of the spine is a rare osseous neoplasm. While previously reported retrospective studies have demonstrated that overall patient survival is impacted mostly by en bloc resection and chemotherapy, the continued management of residual disease remains to be elucidated. This systematic review was designed to address the role of revision surgery and multimodal adjuvant therapy in cases in which en bloc excision is not initially achieved. METHODS A systematic literature search spanning the years 1966 to 2015 was performed on PubMed, Medline, EMBASE, and Web of Science to identify reports describing outcomes of patients who underwent biopsy alone, neurological decompression, or intralesional resection for osteosarcoma of the spine. Studies were reviewed qualitatively, and the clinical course of individual patients was aggregated for quantitative meta-analysis. RESULTS A total of 16 studies were identified for inclusion in the systematic review, of which 8 case reports were summarized qualitatively. These studies strongly support the role of chemotherapy for overall survival and moderately support adjuvant radiation therapy for local control. The meta-analysis revealed a statistically significant benefit in overall survival for performing revision tumor debulking (p = 0.01) and also for chemotherapy at relapse (p < 0.01). Adjuvant radiation therapy was associated with longer survival, although this did not reach statistical significance (p = 0.06). CONCLUSIONS While the initial therapeutic goal in the management of osteosarcoma of the spine is neoadjuvant chemotherapy followed by en bloc marginal resection, this objective is not always achievable given anatomical constraints and other limitations at the time of initial clinical presentation. This systematic review supports the continued aggressive use of revision surgery and multimodal adjuvant therapy when possible to improve outcomes in patients who initially undergo subtotal debulking of osteosarcoma. A limitation of this systematic review is that lesions amenable to subsequent resection or tumors inherently more sensitive to adjuvants would exaggerate a therapeutic effect of these interventions when studied in a retrospective fashion.

Factors predictive of topographical accuracy in spine level localization

BACKGROUND

Pre-operative spine level localization by palpation of anatomical landmarks (ribs, spinous processes) in posterior approaches for surgeries from T4 to L2 is often inaccurate. This can lead to ineffective utilization of procedural time, increased radiation dose, potentially longer skin incision and wrong level surgery. Factors affecting topographical accuracy includes body mass index (BMI) of the patient, congenital or acquired deformity and knowledge of topographical anatomy.

METHODS

All patients had the presumed location of their pathology marked on the skin using anatomical landmarks prior to application of the Target Tape^® (Vancouver, BC, Canada) and verification using an anterior-posterior radiograph. Potential factors predictive of accurate pre-operative spine level localization such as age, gender, BMI, palpable deformity, pathology related interspinous distance (ISPD) and pathology related skin to spinous process distance were evaluated.

RESULTS

A prospective study was performed with 30 consecutive patients undergoing posterior spine surgery (T4 to L2). Accuracy of pathology related spine level localization using anatomical landmarks was only 40%. Pathology related ISPDs of more than 10 mm and palpable deformity was significantly correlated with successful determination of spine levels using anatomical landmarks.

CONCLUSIONS

This study showed that poor spine level localization using anatomical landmarks was associated with pathology related ISPDs of less than 10 mm. Conversely, patients with palpable spinal deformity have their levels easily localized.