Abstract 45. Determining clinically important improvement following surgery for degenerative conditions of the spine: analysis of the Canadian Spine Outcomes and Research Network (CSORN) Registry
Background
There is significant variability in clinically important improvement (CII) criteria for spinal surgery that suggest population- and diagnosis-specific thresholds are required to determine surgical success using patient-reported outcome measures (PROMs). This study establishes surgical CII thresholds for 4 common lumbar degenerative spinal diagnoses using accepted anchor-based methodology and commonly used PROMs.
Methods
CII analysis was conducted using baseline and 1-year data from participants in the Canadian Spine Outcomes and Research Network (CSORN) registry who underwent surgery for lumbar spinal stenosis (LSS), degenerative spondylolisthesis (DS), disc herniation (DH) or degenerative disc (DD) from 2015 to 2018. One-year CII thresholds were determined for the Oswestry Disability Index (ODI), and back and leg Numeric Pain Rating Scales (NPRS). At 1 year, patients reported whether they were much better, better, the same, worse or much worse compared with before their surgery. This was used as the anchor (improved: ≥ “better” v. not improved: ≤ “same”) to determine CII thresholds for absolute change and percentage change for PROMs using a receiver operating characteristic (ROC) curve approach, with maximization of the Youden index as primary criterion. Correct classification rates were determined.
Results
There were 856 participants with LSS (39.1% female, mean age 65.8 yr), 591 with DS (64.1% female, mean age 65.8 yr), 520 with DH (47.5% female, mean age 46.8 yr) and 185 with DD (43.8% female, mean age 50.9 yr). CII for ODI change ranged from −10.0 (DD) to −16.9 (DH). CII for back and leg NPRS change was −2 to −3 for each group. CII for percentage change varied by PROM and pathology group, ranging from −11.1% (ODI for DD) to −50.0% (leg NPRS for DH). Correct classification rates for all CII thresholds ranged from 72.1% to 89.4%.
Conclusion
This work quantifies Canadian CII thresholds for the ODI and back and leg NPRS for 4 common lumbar spinal surgery cohorts, with high classification accuracy. Our results suggest that use of generic CII across different diagnoses in spine surgery is not advised. This study establishes the first comprehensive set of responder criteria in Canada for broader application and specificity in clinical and research settings and for surgical prognostic work.
Abstract 31. Cost-utility analysis of microdiscectomy versus nonoperative management for the treatment of chronic radiculopathy secondary to lumbar disc herniation
Background
The objective of this study was to evaluate costutility when comparing early surgery with 6 months of conservative management at the 2-year follow-up point.
Methods
A decision tree model was created and parameterized using data from a single-centre randomized controlled trial, augmented with institutional cost data. The cost-utility analysis was from the payer perspective. Cost-effectiveness was assessed using the incremental cost-utility ratio (ICUR) and a threshold of willingness to pay (WTP) of Can$50 000 per quality-adjusted life year (QALY). Sensitivity analysis involved probabilistic sensitivity analysis (PSA) and 1-way sensitivity analyses. The results from the PSA were used to construct the 95% confidence interval (CI) around the estimates.
Results
One hundred and twenty-eight patients were included in the study, accounting for potential outcomes and crossover rates between treatment groups. Patients in the surgical group had relatively higher expected costs but had better expected health outcomes. The ICUR was Can$5816 (95% CI $3029–$30 461) per QALY gained. Probabilistic sensitivity analysis demonstrated that the likelihood that early surgical treatment is cost-effective was 0.99 (9848/10 000 from 10 000 Monte Carlo simulations) at the WTP threshold.
Conclusion
Early surgery is cost-effective when compared with nonsurgical care. Decision-makers should ensure timely access to surgical care especially in single-payer systems given the extremely favourable cost-utility ratio.
Abstract 44. Impact of undergoing thoracolumbar spine surgery on patient psychosocial health
Background
The objective of this study was to investigate the impact of thoracolumbar spine surgery on patients’ psychosocial profiles.
Methods
This prospective observational study of consecutive thoracolumbar spine surgeries used patients enrolled in the Canadian Spine Outcomes and Research Network (CSORN) registry at a single tertiary care centre. Measures of interest were collected from 2014 to 2018 at baseline and 24 months postoperatively. These included the Pain Catastrophizing Scale (PCS), Tampa Scale of Kinesiophobia (TSK), Chronic Pain Acceptance Questionnaire (CPAQ), Multidimensional Scale of Perceived Social Support (MSPSS), the Mental Component Summary (MCS) of the SF-12, and patient expectations for surgery impacts on mental well-being. A repeated-measures analysis of variance (ANOVA) was run (α = 0.05). Patients were then divided into cohorts on the basis of whether or not successful improvement in back pain, leg pain and disability was achieved. The parameters for success were a 30% decrease at 24-month follow-up in numerical rating scores for back pain (NRS-B), leg pain (NRS-L) and Oswestry Disability Index (ODI) score or 24-month follow-up scores below the minimal pain (NRS ≤ 3) and disability (ODI ≤ 22) values. Mixed measures ANOVAs were run (α = 0.05).
Results
Data from 214 patients (52.2% female; mean age 57.57 [standard deviation 14.7] yr) were analyzed. The majority of patients (90.7%) expected surgery to improve their mental well-being. On average patients showed significant improvements in PCS, TSK and CPAQ scores (p < 0.05), but not in MCS and MSPSS scores (p > 0.05), and 72.5% reported that surgery met their mental health expectations. Patients belonging to the cohorts who did not meet parameters for success (29.7% for NRS-L, 30.8% for NRS-B and 40.7% for ODI) showed no change on any psychosocial measure of interest (p < 0.05) and were half as likely to report fulfillment of their mental well-being expectations compared with the successful cohort.
Conclusion
Spine surgery results in significant improvement in pain-related psychosocial variables for the majority of patients. While these improvements were not present in patients who did not meet postoperative parameters of successful reduction in pain and disability, it is notable that worsening of psychosocial health was not evident.
Abstract 70. A comparison of functional and quality of life improvement in 6 different types of surgery
Background
More than half a billion people suffer from low back pain, which significantly affects their quality of life. The objective of this study is to compare the outcomes of common lumbar spinal surgeries with each other, and with other successful orthopedic procedures.
Methods
EuroQol 5-dimension (EQ-5D) and Oswestry Disability Index (ODI) improvements of 6 lumbar surgical indications in the Canadian Spine Outcomes and Research Network (CSORN) database were examined. These surgeries were (1) discectomy for radiculopathy, (2) artificial disc for degenerative disc disease (DDD), (3) spinal fusion for DDD, (4) decompression and fusion for degenerative spondylolisthesis, (5) decompression for spinal stenosis and (6) spinal fusion for degenerative scoliosis. Improvements from baseline were assessed at 3, 12 and 24 months. Paired t tests were used to determine patient improvement. EQ-5D outcomes were compared with published data for hip and knee replacement.
Results
A total of 997 patients were identified. All surgical groups had statistically significant improvement from baseline; however, there was large variability within groups. All groups achieved a clinically significant improvement in their functional status (15-point improvement in ODI) except the scoliosis group (ODI score improvements at 24 mo per group were 29.6, 20.3, 17.8, 21.5, 19.1 and 14.7 points, respectively). Comparing quality of life improvement (EQ-5D), all groups improved from baseline and achieved clinically significant improvement (0.1 improvement). At 24 months, improvement was 0.31, 0.21, 0.22, 0.25, 0.22 and 0.29, respectively. Discectomy achieved EQ-5D improvement similar to that achieved by a hip replacement (0.31 v. 0.31). Fusion for DDD, decompression and fusion for spondylolisthesis, decompression for spinal stenosis, and spinal fusion for degenerative scoliosis achieved an equal or greater EQ-5D improvement than that achieved with knee replacement (0.22, 0.25, 0.22 and 0.29 v. 0.22, respectively).
Conclusion
Five lumbar surgeries in this cohort achieved statistical and clinically significant improvement in patients’ function and quality of life. Degenerative scoliosis correction may not result in clinically significant improvement in function but can result in clinically significant improvement in quality of life. The majority of spine surgeries in our list produced results similar to hip and knee arthroplasty.
Abstract 54. The role of frailty and sarcopenia in predicting adverse events and mortality following en bloc resection of primary bone tumours and isolated metastases of the spine
Background
En bloc resection of primary bone tumour and isolated metastases in the spine is associated with high rates of adverse events (AEs). The objectives of this study were 2-fold: (1) to determine whether sarcopenia measured by the ratio of the psoas to vertebral body (VB) and frailty measured by the Spine Tumor Frailty Index (STFI) were predictors of AEs, mortality and length of stay (LOS) and (2) to compare the ratio of psoas to VB measured at L3 and L4 in terms of their ability to predict AEs and mortality.
Methods
In this retrospective analysis of a prospectively collected cohort, patients at a single quaternary care referral centre (January 2009 to December 2019) who underwent an en bloc resection of an isolated spinal metastases or a primary bone tumour were included. Peri-operative AEs, demographic data, primary tumour histology, neurologic status, surgical variables, pathologic margins, Enneking appropriateness, LOS and mortality were all collected in our institutional database. The ratio of the psoas to VB was measured on the computed tomographic (CT) scan at L3 and L4. The association between sarcopenia and frailty measurements and any AEs and 1-year mortality was assessed using logistic regression models. The association between sarcopenia and frailty measurements and LOS was assessed using linear regression analyses.
Results
A total of 112 patients were included in the study. Only 75 patients had sarcopenia measurements available for analysis. The CT measurement at L3 predicted AEs (odds ratio 0.29 per 1 point increase, 95% confidence interval [CI] 0.001–0.74; area under the receiver operating characteristic curve [AUC] 0.85). The CT measurement at L4 performed similarly. The STFI was useful for predicting 1-year mortality in this patient population (OR 5.95, 95% CI 1.21–29.18; AUC 0.80). Sarcopenia measurements and frailty indices were not significant predictors of LOS in hospital.
Conclusion
Sarcopenia measurements, the ratio of psoas to VB at L3 and L4, and STFI are useful predictors of AEs and mortality following an en bloc resection of spine tumours.
Abstract 27. Feasibility of achieving planned surgical margins in primary spine tumour: a PTRON study
Background
Appropriate oncologic resection of primary spine tumours is associated with lower recurrence rates. Even in the most experienced hands, however, executing a meticulously drafted plan sometimes fails. The goal of this study was to determine how successful surgical teams are at achieving planned surgical margins and how successful surgeons are at assessing margins intraoperatively. A secondary objective was to identify factors that might influence successful execution of the planned resection.
Methods
Primary Tumor Research and Outcome Network (PTRON) is a multicentre international prospective registry for the management of primary tumours of the spine. Using this registry, the primary end points of the present study were to compare (1) the planned surgical margin and (2) intraoperative assessment of the margin by the surgeon to the postoperative assessment of the margin by the pathologist. Univariate analyses were used to assess factors associated with successful execution of the planned resection.
Results
A total of 258 patients were included. Successful achievement of the surgical plan was attained in 193 patients (74.8%). Margins achieved intraoperatively were correctly assessed in 206 patients (79.8%) compared with the final pathologist assessment. On univariate analysis, the location of the tumour and the number of stages had a statistically significant influence on successful achievement of planned margins.
Conclusion
To our knowledge, this is the largest study to assess how successful experienced surgical teams are at achieving their surgical plans. We showed that even in high-volume cancer centres, planned surgical margin can only be achieved in three-quarters of cases. The morbidity of the proposed intervention has to be seen in the context of the expected rate of success to optimize patient management and surgical decision-making.
Abstract 32. Care providers’ perspectives on potential expansion of medical assistance in dying criteria to persons with acute spinal cord injury: a qualitative study
Background
Provision of medical assistance in dying (MAiD) under Bill C-14 currently requires the patient to have a reasonably foreseeable death. Legislative changes are anticipated to remove this requirement in response to a recent ruling in Quebec. Patients with traumatic spinal cord injuries (tSCI) have higher rates of suicidal ideation and self-harm for some time after the injury. Providing access to MAiD might, therefore, result in premature death before postinjury adaptation can take place. This project explored the perspectives of care providers of people with tSCI concerning end-of-life decisions, the impact of expanding MAiD criteria, and the role of care providers in cultivating hope.
Methods
We conducted an interpretive descriptive qualitative study. Semistructured interviews were conducted with 19 multidisciplinary team members of the surgery and rehabilitation teams that care for patients with tSCI. Interviews were recorded and transcribed and thematic analysis was conducted.
Results
Participants described variability in how people with tSCI initially responded to their injury. These responses included shock, denial, an inability to comprehend their life changes, depressive symptoms and occasional suicidal ideation or actions. Participants had various responses to the potential broadening of the criteria for MAiD. Some were highly concerned about premature death, while others expressed confidence that the existing processes would protect against impulsive decision-making.
Conclusion
Expanding the criteria for MAiD may provide a greater range of choices for people with tSCI but could also increase premature deaths. Recommendations include increased involvement of eligibility assessors with expertise in spinal cord injury as well as a longer mandatory waiting period, especially in young, vulnerable people with an acute tSCI.
Abstract 22. Does wait time for transfer from acute care to rehabilitation affect the outcomes following a traumatic spinal cord injury? A prospective cohort study
Background
Delay in transfer from acute care to inpatient functional rehabilitation (IFR) after an acute traumatic spinal cord injury (tSCI) is not uncommon. To this day, its impact on the length of rehabilitation and functional outcomes remains unknown, especially for vulnerable groups of SCI patients. The first objective was to determine whether the delay in transfer from acute care (no. of elapsed days between rehabilitation readiness and discharge from acute care) affects the IFR length of stay and functional status following IFR. The secondary objective was to further investigate this relationship with respect to age (< 65 yr v. ≥ 65 yr) and the severity of the tSCI (American Spinal Injury Association Impairment Scale grade A, B, C and D), when accounting for confounding factors.
Methods
A prospective cohort study including 277 patients admitted to a single level 1 SCI trauma centre was conducted. Partial correlations were performed between the delay in transfer, IFR length of stay and the Spinal Cord Independence Measure (SCIM) at follow-up, adjusting for relevant confounding variables. The same analyses were carried out after stratifying on the basis of age group and the severity of the tSCI.
Results
The mean delay in transfer from acute care was 7.3 (standard deviation 6.4) days (median 6 d; interquartile range 2–10 d). Delay in transfer was not associated with the IFR length of stay or functional status when adjusted for covariables. However, people aged 65 years and older with a severe injury had lower functional status when exposed to a longer delay in transfer (r = −0.87, p = 0.02). A delay in transfer from specialized acute SCI care up to 29 days had no impact on the IFR length of stay and functional outcome following tSCI.
Conclusion
A multidisciplinary acute rehabilitation team in a specialized SCI centre may be able to minimize negative effects of delayed admission to IFR. However, more attention should be given to elderly people who have sustained severe SCI when they face delays in transfer from acute care.
Abstract 86. Investigating and validating quantitative MRI biomarkers for demyelination, axon integrity and inflammation after traumatic spinal cord injury
Background
Traumatic spinal cord injuries (SCI) are heterogeneous in severity, neurologic level and injury mechanism. Specific aspects of tissue damage, such as axon loss, demyelination, inflammation and edema, vary spatially and over time after injury. Empirical in vivo measurements of SCI damage would be very useful for prognosis and as a biomarker for clinical trials. Our overall objective is to establish magnetic resonance imaging (MRI) biomarkers for damage after traumatic SCI by leveraging our unique opportunity to correlate quantitative MRI measures with both the underlying pathology of SCI and clinical neurologic impairment.
Methods
Eleven whole formalin-fixed spinal cords from the International Spinal Cord Injury Biobank underwent high-field advanced MRI scans sensitive to a range of tissue components including myelin, axons, edema and inflammation. Injury–death interval (IDI) ranged from 1 to 112 days. After MRI, the cord was sectioned and stained with histopathologic stains for myelin phospholipids, myelin proteins, axons and inflammatory cells. MRI and histology in ascending sensory and descending motor white matter tracts were quantitatively compared.
Results
Three MRI metrics sensitive to myelin (myelin water fraction [MWF], inhomogeneous magnetization transfer [ihMT] and radial diffusivity [RD] from diffusion tensor imaging) were found to significantly correlate with Luxol fast blue (LFB) staining for myelin phospholipids in the injury epi-centre. RD had the strongest correlation with LFB (R = −0.719), followed by MWF (R = 0.675) and then ihMT (R = 0.650). We saw evidence for Wallerian degeneration in MRI biomarkers for myelin, axons and inflammation in the 2 cords with IDI greater than 60 days but not in cords with shorter IDI. Histopathologic data analysis is ongoing as well as MRI biomarker correlation with neurologic impairment.
Conclusion
The 3 myelin-sensitive MRI metrics investigated were validated as myelin biomarkers in human SCI. Initial analysis establishes a time frame for the detection of Wallerian degeneration with these MRI methods. Further analysis of this exciting data set will validate additional MRI metrics and give insight into the histopathology of SCI.
Abstract 23. Does participating in a national spinal cord injury registry improve actual patient outcomes?
Background
Maintaining patient registries is both costly and time consuming, and it is therefore important to assess their actual benefits for patient-centred care to justify their continued use. The aim of this study is to determine if participating in a national spinal cord injury (SCI) registry improves actual patient outcomes and continuum of care.
Methods
This cohort study compared the outcomes of 444 patients who participated in the Rick Hansen Spinal Cord Injury Registry and 140 patients who declined to participate. Multivariable regression analyses were performed to assess the association between patient participation and outcomes, while accounting for covariables. The main outcomes were compliance with 12-month follow-up, admission to inpatient rehabilitation, inpatient length of stay, 1-year mortality and acute complications.
Results
Participating in the registry was the only significant predictor of improved compliance with follow-up (adjusted odds ratio [OR] 23.40, 95% confidence interval [CI] 13.25–41.32). It was also associated with reduced 1-year mortality (OR 0.08, 95% CI 0.03–0.22), decreased occurrence of pressure injury (OR 0.39, 95% CI 0.24–0.64) and increased admission to inpatient rehabilitation (OR 2.42, 95% CI 1.53–3.84). Participating in the registry was not associated with pneumonia, nor with the acute or rehabilitation length of stay.
Conclusion
This study demonstrates the existence of actual patient-centred benefits in terms of outcomes and continuum of care when patients consent to participate in a national SCI registry. There is a need to improve the outcomes of patients declining to participate in a SCI registry.
Abstract 79. Can individuals expect normal quality of life following traumatic spinal cord injury? A cohort study compared with Canadian normative data
Background
This study aims to describe the expectations to achieve normal quality of life (QoL) among Canadian traumatic spinal cord injury (tSCI) patients when compared with Canadian normative QoL values based on age and sex. It also aims to determine the effect of older age and severity of SCI on achieving normal QoL. We defined normal QoL as a score within 2 standard deviations of the mean of one’s sex and age group.
Methods
A review of prospectively collected data was conducted on patients admitted acutely at a single level 1 trauma centre. We included patients older than 18 years of age with a baseline level of injury between C1 and S2. We assessed QoL using the SF-36 physical and mental component summary (PCS and MCS) scores obtained within 1 year after injury.
Results
Of the 264 individuals included in the study, 38.3% displayed normal PCS, whereas 77.8% displayed normal MCS. The proportion of patients who displayed normal PCS was significantly higher in individuals aged 65 years or older (61.3% v. 31.2%; χ2 = 17.5; p < p < 0.001) and in patients with less severe SCI (χ2 = 38.7; p < 0.001). We noted no differences in MCS across age groups or grades of severity for SCI. When we adjusted for potential confounders, age group was no longer significantly associated with achieving normal PCS following tSCI.
Conclusion
Accounting for age-related QoL variations in the normal population is important when counselling patients after tSCI. More severe SCI are associated with a decreased likelihood of reaching normal PCS, while the likelihood of achieving normal MCS is not affected. Geriatric tSCI patients are as likely as younger patients to experience normal QoL, and a patient’s age should not influence clinicians when discussing long-term expectations for QoL.
Abstract 79. Is the conversion of the American Spinal Injury Association Impairment Scale grade clinically meaningful for functional recovery in all patients with traumatic spinal cord injury?
Background
The objective of this study was to determine whether the conversion of the American Spinal Injury Association Impairment Scale (AIS) or the achievement of a specific grade better reflects functional status and independence 1 year after a traumatic spinal cord injury (tSCI).
Methods
Using data from a prospective cohort of patients with tSCI managed at a single level 1 trauma centre, we assessed the impact of the conversion of AIS grade and the final AIS grade achieved on the 1-year Spinal Cord Independence Measure (SCIM) score and the recovery of functional independence.
Results
The conversion of 1 AIS grade was associated with improvement in the SCIM score only in individuals with an initial AIS grade C or D. Regardless of their initial grade, individuals who achieved a final AIS grade D had a significantly higher SCIM score at 1 year than those who did not reach AIS D (89.3 ± 15.2 and 52.1 ± 20.4 respectively, p < 0.001); they also were more likely to reach functional independence than those who could not achieve AIS D (68.5% and 3.6%, respectively, p < 0.001) irrespective of the number of grades converted. In multivariable analysis, significant predictors of the SCIM were final AIS grades D (β 3.716, 95% confidence interval [CI] 2.77–4.66) and E (β 4.422, 95% CI 2.91–5.93).
Conclusion
Achieving AIS grade D or better 1 year after tSCI is associated with improved function and is more clinically meaningful than AIS grade conversion. Conversion of 1 AIS grade is meaningful for individuals with initial AIS grades C or D and less clinically useful for those with initial AIS grades A and B.
Abstract 101. Predicting massive intraoperative blood loss in adult spinal deformity surgery
Background
Because of inherent patient and surgical factors, some adult spinal deformity (ASD) patients are at higher risk of larger blood loss. This is associated with increased risks of complications, coagulopathy and higher requirements for blood component replacement intraoperatively. This study aims to develop and validate a model based on patient characteristics and surgical strategies to predict which patients undergoing ASD surgery are at greater risk of massive intraoperative blood loss.
Methods
This was a retrospective analysis of a multicentre prospective ASD database. Massive blood loss (mEBL) was defined as an intraoperative blood loss greater than 7% of a patient’s ideal body weight. Multivariate logistic regression modelling was used to build a prediction model of mEBL. Potential predictors were identified using univariate analysis. The model was built using a combination of backward elimination and bootstrap selection. Model fit was assessed using the Hosmer–Lemeshow test and the receiver operating characteristic (ROC) curve. Split sample internal cross-validation was performed. The impact of mEBL on complications and intensive care unit (ICU) stay was assessed through multivariate Poisson and logistic regression, adjusting for baseline patient demographics and magnitude of surgery.
Results
A total of 1205 patients met the inclusion criteria, and mEBL occurred in 7.8% (94/1205) of cases. In this cohort, mEBL was an independent risk factor for major complications (incidence rate ratio 2.89, p < 0.001) and postoperative ICU stay (odds ratio [OR] 4.68, p = 0.001). Predictors of mEBL included revision surgery (OR 1.66, p = 0.05), performing a 3-column osteotomy (OR 2.65, p < 0.001), number of levels fused (OR 1.19, p < 0.001), number of levels decompressed (OR 1.15, p = 0.004) and number of direct lateral interbody fusion (DLIF) interbodies (OR 0.69, p = 0.066). The predictive model had a good discrimination (ROC curve 0.76) and good calibration (Hosmer–Lemeshow p = 0.39), which held true when we performed split-sample cross-validation.
Conclusion
We built and validated a model to predict massive intraoperative blood loss in ASD surgery. This tool would be of particular help to members of the anesthesia team, allowing them to identify preoperatively which patients are at greater risk and plan intraoperative care and fluid management accordingly.
Abstract 102. Use of preoperative opioids is a risk factor for persistent chronic postoperative opioid use in adult spinal deformity patients
Background
Opioid use in surgical patients is widespread. A majority of patients wish to undergo surgery to stop medication use. This study examines persistent chronic postoperative opioid use in adult spinal deformity (ASD) patients and the impact on chronic preoperative opioid dependence in this patient population.
Methods
This was a single-centre study of consecutive ASD patients. Patients were enrolled in a prospective registry. Data on opioid use were collected through chart reviews and converted to oral morphine equivalent per day (MED). Patients were divided into 2 groups on the basis of preoperative opioid use (opioid naive and chronic opioid). The 2 groups were compared in terms of baseline demographics, radiographic parameters, surgical parameters, revision surgery and opioid use 1 and 2 years following surgical intervention.
Results
A total of 142 patients were included at baseline (opioid naive n = 51, and chronic opioid n = 91). One-year opioid data were available for 86.6% of patients. Two-year opioid data were available for 71.1% of patients. The 2 groups were similar in terms of baseline demographics, baseline radiographic parameters and surgical invasiveness. Revision rate for the overall cohort was 30.7% at 2 years, with no statistically significant difference between the 2 groups. One year after surgery, 62.7% of those on chronic opioids before surgical intervention continued to use opioids, versus only 14% in the opioid naive cohort (p < 0.001). One-year postoperative average opioid use was 55.3 MED for the chronic preoperative opioid group versus 7.44 MED for the preoperative opioid naive group (p = 0.005). Two-year data showed similar results, with 59.4% persistent opioid use among those on chronic opioids before surgery (v. 12.9% in those who were opioid naive before surgical intervention, p < 0.001). Two-year postoperative average opioid use was 47.42 versus 3.49 MED (p = 0.014).
Conclusion
Sixty-four percent of ASD patients were on chronic opioid analgesia before surgery. The majority (60%) of these patients continued to use opioids 2 years after surgical intervention.
Abstract 102. Comparison of a general (NSQIP) and spine specific (SAVES) database for the identification of spine surgery acute care adverse events
Background
This project compares the general National Surgical Quality Improvement Program (NSQIP) and spine surgery specific Spine Adverse Events Severity System (SAVES) for identification of adverse events (AE’s) and per-patient rates for AEs for adult patients undergoing major spine surgery.
Methods
All patients, excluding trauma patients, from 2011 to 2018 were identified using Current Procedural Terminology codes in the NSQIP database and matched in SAVES.
Results
Analysis identified 1460 patients in NSQIP with complete records in SAVES. The average age of included patients was 57.6 (standard deviation 15.8) yr and 54.3% of patients were male. Indications for surgery were varied, with 63.5% of procedures performed electively. Baseline demographic analysis revealed that 45.8% of patients had severe systemic disease, 18% were smokers, 9.8% had diabetes and 5.8% had metastatic cancer. Average length of stay was 13.7 days postoperatively, with 97 patients (6.6%) staying for more than 30 days. NSQIP identified 1008 AEs in 580 patients (39.7%) while SAVES identified 2759 individual AEs in 776 patients (53.1%). Analysis of the 2011–2018 patient cohort revealed that SAVES identified a larger number of adverse events and a larger number of patients who suffered multiple adverse events than NSQIP. SAVES and NISQIP demonstrated 6 specific comparable AEs. SAVES captured 2.28 as many directly comparable adverse events (426) as NISQIP (187) events in these categories. SAVES specific categories identified 178 intraoperative events (e.g., dural tear) not captured by NSQIP. NSQIP specific categories identified 749 medical interventions in 473 patients (32.4%).
Conclusion
SAVES identified more AEs and more AEs per person than NSQIP. Furthermore, SAVES identified spine surgery specific intraoperative and postoperative complications of direct relevance to patient outcomes. This study highlights the value of specialty-specific AE databases in the accurate capture of adverse events specific to a specialty or subspeciality field. Accurate capture of AEs is essential to the identification of risk factors for poor outcome in spine surgical patients and highlights the importance of appropriate database selection and adoption in surgical quality improvement.
Abstract 55. Trends in length of stay at a quaternary spinal care centre from 2006–2020
Background
Length of stay (LOS) is used by the Canadian Institutes of Health Research as a surrogate for care complexity and is a critical determinant of bed occupancy, capacity and service provision. Over the past 15 years we have undertaken numerous initiatives to reduce LOS of select spine surgical populations. The primary goal of this study was to assess changes in and determinants of LOS at a high-volume quaternary care spine centre. Secondary goals were to identify opportunities for improvement and determinants of future service planning.
Methods
Data were prospectively collected on all consecutive patients from 2006 to 2020 and included diagnostic category (degenerative, oncology, deformity, trauma, other), mean, median and standard deviation (SD) LOS.
Results
A total of 14 673 patients were included. Mean age increased from 48.4 years in 2006 to 58.2 years in 2020. The proportion of patients with oncologic disease increased from 6.7% in 2007 to 12.3% in 2020. The proportion of patients with degenerative disease increased from 35.6% in 2014 to 44.3% in 2020. Despite this, overall mean LOS decreased from a mean of 19.5 (SD 43.4) days in 2006 to 10.7 (SD 13.8) days in 2020. Mean LOS for patients with degenerative disease increased from 3.9 (SD 6.0) days in 2006 to 6.8 (SD 23.4) days in 2020. Mean LOS for patients with oncologic disease increased from 15.0 (SD 19.5) days in 2006 to 20.5 (SD 12.2) days in 2019. Proportions and mean LOS for patients with deformity (14.6%, 10.2 d) and trauma (22.7%, 24.6 d) remained stable over time.
Conclusion
This is the first study to comprehensively analyze trends in LOS over time in spinal surgery. Total population LOS has decreased in the last 15 years because of multiple efforts to enhance peri-operative care. However, increasing numbers of patients treated for degenerative and oncologic disease are staying longer in hospital with significant variability in LOS. These findings provide opportunities for intervention and improvement, targeted at specific populations, to reduce length of hospital admission.
Abstract 89. The impact of the COVID-19 pandemic on scheduled adult spine surgery in Toronto academic health sciences centres (AHSC): a wave 1 through early wave 2 experience
Background
The pandemic continues to have a significant impact on scheduled surgery. Quantifying the surgical backlog and demand for quality-based procedures is necessary to advocate for resources supporting spinal health for Canadians. This study determined the backlog of adult spine surgeries across Toronto academic health sciences centres (AHSCs), compared activity to common degenerative joint conditions and described our local and regional health system approach in managing demand.
Methods
Surgical activity was quantified through available local regional and provincial administrative databases.
Results
Fiscal year-to-date data (April–October) demonstrated that 588 patients were waiting for spine surgery (with an estimated 86-case backlog compared with the same period last year). The median wait was 9 months. Year-to-date volumes were 438 cases (17% reduction compared with the same time last year, range −25% to 23% across 4 adult centres; during this time 1 centre recruited an additional spine surgeon). Year-to-date hip and knee surgical volumes were 1105 and 1961, respectively (−35% and −48% reduction); 990 and 1947 patients awaited surgery, with a backlog of −149 and −397 compared with last year. Compared with 2019, surgery in Ontario ramped up 60% in the weeks leading up to Provincial Directive 2 in mid-March, dropping approximately 90% by mid-April and by approximately 80% by surgical restart of late May, peaking at approximately 15% above 0% in early August and trending between −5% and −30% throughout the fall. In late September, the province issued a 1-time targeted funding initiative for hospitals to prioritize and address surgical backlog including quality-based procedures (QBP) cases.
Conclusion
A significant reduction in scheduled adult spine surgery was noted during the first 6 months of the fiscal year, with a significant ongoing backlog. Scheduled surgical activity was significantly curtailed during wave 1 of the pandemic to create and protect hospital capacity for COVID-related care. A decrease in referral volumes, in part, may explain the observed negative backlog estimates for hip and knee procedures compared with 2019. From the wave 1 experience, most AHSCs are implementing a staged reduction plan during wave 2 that aims to better protect scheduled surgical activity.
Abstract 60. Patient acceptance and satisfaction with virtual care in Ontario during and after COVID-19 lockdown restrictions
Background
COVID-19 closures significantly reduced available outpatient services and management resources for patients with low back pain (LBP). In response, Rapid Access Clinics for Low Back Pain in Ontario implemented virtual care (VC) to minimize anticipated backlog and patient deterioration. To optimize rapid implementation, we needed to understand patients’ preferences related to VC in the context of an assessment by an unknown health care provider. Objectives of this study were to determine (1) rates and reasons for accepting or declining an initial virtual LBP assessment and (2) satisfaction with VC for LBP.
Methods
A mixed-methods approach was used. Telephone surveys were completed to determine accept–decline VC rates with reasons during the lockdown period of the pandemic (no in-person option available) and following the lockdown period (both in-person and VC options available). For those who participated in VC an electronic questionnaire with fixed response options and opportunities for open-ended comments was distributed via email. Descriptive statistics and qualitative thematic analysis were applied to the data.
Results
During lockdown (April and May), 63 survey patients were offered VC and 34 (54%) accepted. Following lockdown (July and August), 102 survey patients were offered either VC or in-person assessment. Sixty-four (63%) accepted VC. During both periods, the main reasons for declining VC were no video, email, computer or Internet (17%), lack of confidence with technology (24%) and preference for in person (8%). A total of 147 postassessment VC satisfaction questionnaires were completed (June–November). Based on a 5-point Likert scale (5 most positive), overall satisfaction with virtual low back assessment was 4.7 and the likelihood of participating in VC again was 4.7. Qualitative analysis revealed 3 main themes: the importance of human connection, patient-perceived virtual physical examination limitations and VC efficiencies.
Conclusion
Presented with a choice of onsite or VC for LBP after the pandemic lockdown, the majority of patients chose VC. The reasons for declining VC were predominantly related to technologic limitations regardless of timing and assessment type offered. With a high satisfaction rate, VC represents an efficient, patient-centric option for initial assessment and management of LBP.
Abstract 39. Prospective randomized control study to evaluate the role of injection Cerebrolysin in operated cases of degenerative cervical myelopathy
Background
Cerebrolysin is a product obtained by the enzymatic degradation of fat free pig brain and is said to have neuroprotective, neurotrophic and neuroregenerative properties. It has been studied with variable success in a variety of neurodegenerative disorders. The aim of this study was to compare the effects of Cerebrolysin in operated cases of degenerative cervical myelopathy (DCM).
Methods
This prospective randomized controlled trial was conducted at a tertiary care institute in Mumbai. Sixty operated cases of DCM were randomly divided into 2 groups. All cases were operated by the same surgical team. The first group was given injection Cerebrolysin 5 mL diluted in 100 mL normal saline over 30 minutes once a day for 21 days postoperatively. The second group was given a placebo for the same duration. Modified Japanese Orthopedic Association (mJOA) scores and visual analogue scale (VAS) scores were used to document functional outcomes at 3 weeks, 3 months, 6 months and 1 year. Recovery of hand function was separately accessed by improvement in hand power and sensations. ASIA (American Spinal Injury Association) scores were used to study postoperative neurologic recovery.
Results
Preoperative mJOA and VAS scores were comparable between the 2 groups (p < 0.05). Both groups showed significant improvement in both mJOA and VAS scores at 3 weeks, 3 months, 6 months and 1 year follow-up (p < 0.01). On comparing the 2 groups, there was no difference in improvement in mJOA and VAS scores. However, the Cerebrolysin group showed significant improvement in hand function at 1 year compared with the placebo group (p = 0.03). Postoperative neurologic recovery was better in the Cerebrolysin group, with 66.7% patients showing complete neurologic recovery compared with 56.7% for the placebo group, but this difference was not statistically significant (p = 0.32). No patient had any adverse reactions to Cerebrolysin.
Conclusion
Use of Cerebrolysin in postoperative cases of DCM is safe and can result in improved neurologic recovery.
Abstract 47. Association between patient-reported outcomes and construct length in posterior cervical instrumentation for cervical spine myelopathy
Background
In multilevel posterior instrumented fusion, crossing the cervicothoracic (CT) junction has been associated with decreased rate of reoperation and pseudarthrosis while resulting in longer surgeries with increased blood loss. However, the impact on patient-reported outcomes remains unknown. The objectives were to determine (1) whether crossing the CT junction influenced patient-reported outcomes (PROs) at 12 months after surgery and (2) the association with intraoperative blood loss (IOBL), length of stay (LOS) and perioperative adverse events (AEs).
Methods
This is a retrospective study of a prospectively multicentric followed cohort of patients enrolled in the cervical spine myelopathy study between April 2015 and October 2020. Patients who underwent a posterior instrumented fusion greater than 4 levels (between C2 and T2) with 12 months of follow-up were included. Patient demographics, comorbidities, PROs, surgical details, adverse events and length of stay were abstracted.
Results
Data for a total of 152 patients were analyzed (75 did not cross the CT junction and 77 did). At baseline, patients who underwent a construct crossing the CT junction had more comorbidities, were more likely to be female and had worse modified Japanese Orthopedic Association (mJOA), EQ-5D and Neck Disability Index (NDI) scores (p < 0.05). Surgical duration was longer in the group crossing the CT junction (160 v. 188 min, p < 0.01). IOBL, perioperative AEs and LOS were not statistically different between groups (p > 0.05). When adjusted for baseline scores, there was no statically significant difference in NDI, MJOA, mental component score (MCS), physical component score (PCS) and arm and neck pain NRS change between the groups at 12 months. Adjusted EQ-5D changes were 0.09 and 0.16 in those whose underwent a construct crossing and those who did not, respectively (p = 0.044).
Conclusion
In this cohort of patients with posterior instrumented fusion, crossing the CT junction was associated with longer surgical duration but similar IOBL, LOS and AEs. Improvements in PROs were not significantly different at 12 months between the groups, except for EQ-5D.
Abstract 52. Rate of revision surgery at adjacent and same segment for cervical disc replacement versus anterior cervical discectomy and fusion
Background
In recent years, cervical disc replacement (CDR) has gained popularity. The superiority of CDR over anterior cervical discectomy and fusion (ACDF) in terms of rates of secondary surgeries has not been demonstrated in long-term follow-up. This study compares the rates of reoperation in CDR and ACDF for treatment of cervical degenerative disc disease.
Methods
A population-based cohort study was conducted using health administrative databases including patients undergoing ACDF or CDR between October 2005 and March 2018. Patients receiving CDR versus ACDF were identified using physician claims recorded in the Ontario Health Insurance Program database. Additional details of surgical procedure were obtained from the Canadian Institute for Health Information hospital Discharge Abstract Database. The primary outcome measured was the presence of revision surgery in the cervical spine, defined as an operation more than 30 days from the index procedure. Secondary outcomes were immediate–acute complications within the first 30 days of the index operation.
Results
A total of 5207 patients were included. Mean follow-up was 2728 days for CDR and 2542 days for ACDF. The rate of revision surgery was 7.5% for ACDF and 8.9% for CDR (p = 0.41). CDR trended toward being a risk factor for time to revision in multilevel surgeries (hazard ratio 2.277, 95% confidence interval [CI] 0.993–5.223, p = 0.05). ACDF had higher rates of acute complications (7.6% v. 3.3%, p < 0.01). Multilevel surgery was a predictor of acute complications (odds ratio [OR] 1.329, 95% CI 1.064–1.660, p = 0.012) including dural tears (OR 2.496, 95% CI 1.489–4.184, p < 0.001) but not infections. CDR was associated with shorter length of hospital stay (1.42 ± 0.87 v. 2.00 ± 3.08 d, p < 0.005).
Conclusion
The study did not demonstrate superiority of CDR over ACDF in terms of revision rates at index or adjacent level of the cervical spine for single-and multi-level procedures. CDR may have advantages over ACDF in the acute postoperative phase, with shorter length of hospital stay and lower overall complication rates within 30 days.
Abstract 104. Analysis of complication rates in cervical spine surgery between older patients and younger cohorts using the CSORN registry: Is age just a number?
Background
An ambispective review was conducted of consecutive cervical spine surgery patients enrolled by the Canadian Spine Outcomes and Research Network (CSORN) between January 2015 and September 2019. The objective was to compare complication rates between elderly patients and younger cohorts in the intraoperative, perioperative, 3-month postoperative and 1-year postoperative periods.
Methods
The incidence of degenerative spine disease is increasing, and hence more elderly people are having surgeries. Few studies have examined the temporal nature of complications of cervical spine surgery in the geriatric age group when compared with younger cohorts.
Results
A total of 860 patients met our study review criteria. There were 195 (22.7%) aged 65 years and older and 665 (77.3%) aged less than 65 years. Intraoperative adverse events between the 2 study groups did not differ significantly (3.9% in patients aged < 65 yr v. 5.6% in patients aged ≥ 65 yr). Perioperatively, the elderly group had more adverse events: 46 (23.6%) versus 83 (12.5%). The most common adverse events were urinary retention (2.3% in the < 65 yr group v. 5.1% in the ≥ 65 yr group), dysphagia (2.1% in the < 65 yr group v. 3.1% in the ≥ 65 yr group) and postoperative pain prolonging hospital stay or requiring readmission (1.2% in the < 65 yr group v. 1.5% in the ≥ 65 yr group). Adverse events at 3 months and 6 months after surgery did not differ significantly between the 2 groups. When we conducted covariate regression analysis, only intraoperative blood loss was associated with not having an intraoperative adverse event (p < 0.001). In the perioperative period, more operated levels, less operating time, shorter length of hospital stay and age less than 65 years were associated with not having a perioperative adverse event. At 3-month and 1-year follow-up, there were no statistically significant factors associated with not having adverse events between the 2 study arms.
Conclusion
In the 2 age groups, cervical spine surgery is associated with a comparable rate of adverse events in the intraoperative period and the 3-month to 1-year postoperative period. In the 1 month following surgery, elderly patients have significantly more adverse events. Modifiable risk factors that could increase the incidence of adverse events include number of comorbidities, surgical level, surgical approach, intraoperative blood loss and length of hospital stay.
Abstract 49. Factors associated with increased length of stay in degenerative cervical spine surgery: cohort analysis from the Canadian Spine Outcomes and Research Network (CSORN)
Background
Prolonged length of stay (LOS) following spine surgery incurs an increased risk and cost for patients and hospitals. Only small studies have investigated the association of patient, surgical and preoperative factors with LOS following commonly performed cervical spine procedures. The objectives were to report on the variability and determine factors associated with prolonged LOS in Canada following anterior cervical discectomy and fusion (ACDF) of less than 3 levels and posterior cervical fusion (PCF).
Methods
This is a retrospective study of prospectively collected multicentre data consisting of patients enrolled in the Canadian Spine Outcomes and Research Network (CSORN) between January 2015 and October 2020. Patient demographics, cervical pathology, symptom duration and severity, preoperative patient-reported outcomes, surgical centre, perioperative adverse events (AEs) and LOS were abstracted. Multivariable logistic regression analysis was performed to determine the association and odds ratio for risk-adjusted factors on prolonged postoperative LOS, defined as greater than the median LOS per procedure. Bootstrapping statistical techniques were used to internally validate the prediction models.
Results
A total of 1085 patients were included (ACDF n = 670, PCF n = 415). Mean LOS for the ACDF cohort was 2.0 days (standard deviation [SD] 2.5 d) whereas it was 5.7 days (SD 4.9 d) for the PCF cohort. Median ACDF LOS was 1.0 day (interquartile range [IQR] 0–45 d) and 5.0 days (IQR 1–57 d) for the PCF cohort. Predictors of prolonged LOS following ACDF were female sex (p = 0.013), longer operation time (p < 0.001), greater intraoperative blood loss (p = 0.032) and the occurrence of any perioperative AEs (p < 0.001). Predictors of prolonged LOS following PCF included the occurrence of any perioperative AEs (p < 0.001), nonmarital status (p = 0.013), having no more than a high school education (p = 0.02) and nonsmoking status (p = 0.032). Internal validation receiver operating characteristic (ROC) curves yielded high correct classification values.
Conclusion
Our study identified several patient, surgical and procedural factors predictive of prolonged LOS following ACDF or PCF. Further studies are needed to determine if quality improvement strategies targeted at enhanced recovery after surgery improve patient care quality and reduce LOS.
Abstract 51. Association between preoperative sagittal alignment and radiographic measures of decompression following cervical laminectomy
Background
This study aimed to determine the association between preoperative cervical sagittal alignment and the extent of radiographic postoperative cord decompression following laminectomy. Other objectives included an assessment of the correlation between laminectomy and increasing numbers of levels decompressed on the change in alignment, as well as the effect of laminectomy on preexisting spinal cord signal abnormality.
Methods
This retrospective cohort study included patients who underwent cervical laminectomies, without fusion, between 2015 and 2020. Chart review was used to collect baseline variables and to measure radiographic changes using preoperative and postoperative magnetic resonance imaging (MRI) scans. Cervical sagittal alignment in the form of the C2–C7 Cobb angle, the width of the spinal cord and the cerebrospinal fluid (CSF) space in front of and behind the cord was measured preoperatively and postoperatively. The correlation between change in measured parameters and preoperative cervical sagittal alignment was assessed using the Spearman correlation.
Results
Thirty-five patients were included. Their average age was 65.29 (standard deviation [SD] 10.98) years. The majority of patients (80%) underwent laminectomies at 3–4 levels. Average preoperative sagittal alignment determined by the Cobb angle was 6.05° (SD 14.17°), while the average postoperative Cobb angle was 3.15° (SD 16.64°) and the change was not statistically significant (p = 1.0). Eleven patients (32%) had preoperative kyphotic sagittal alignment. The average time from surgery to postoperative MRI scan was 20.44 (SD 13.18) months (range 3–39 mo, median 18.5 mo, interquartile range 23.5 mo). Laminectomy was associated with increased cord width and increased space in front of and behind the cord (p values < 0.001). There was no statistically significant association between increasing levels of decompression and change in cervical spine sagittal alignment (p = 0.55). Spinal cord signal abnormality persisted after decompression. There was a moderate correlation between lordotic preoperative cervical sagittal alignment and change in space in front of the cord (correlation coefficient 0.337350, p = 0.048) and change in cord width (correlation coefficient 0.389, p = 0.021).
Conclusion
Severity of preoperative kyphotic sagittal alignment is associated with decreased extent of decompression and spinal cord drift. The preoperative sagittal alignment is not significantly associated with the change in alignment. Increasing number of levels decompressed does not worsen alignment.
Abstract 3. Analysis of the morphometric change in the uncinate process of cervical spondylosis patients: a study of radiologic anatomy
Background
Although there has been much research focusing on the relationship between the vertebral artery and uncinate process (UP), there are no publications concerning the difference in the dimensions of the UP between the normal spine and degenerative spine, especially in Chinese patients. The purpose of this study was to determine the anatomic parameters that can be used as a guide for the procedure in intervertebral foramen decompression and for analysis of the morphometric change in the UP of patients with cervical spondylosis.
Methods
Forty patients from January 2016 to January 2019 were enrolled in this study. Three-dimensional computed tomographic scans of the cervical spine were performed. The patients were divided into 2 groups: a nondegenerative cervical spine group (20 cases) and a degenerative cervical spine group (20 cases). Six parameters concerning the height, width and angle of the UP were measured.
Results
In the nondegenerative group, the average pedicle width was 3.63–5.91 mm from C3 to C7. The average width of safe UP resection will be 3.06 mm at C3, 3.12 mm at C4, 3.28 mm at C5, 2.74 mm at C6 and 2.01 mm at C7. The average safe depth will be 6.04 mm at C3, 6.52 mm at C4, 7.61 mm at C5, 6.07 mm at C6 and 5.09 mm at C7. There were statistically significant differences between the degenerative group and the nondegenerative group, especially for the minimum height of UP, maximum height of UP, medial border’s distance of UP and lateral border’s distance of UP.
Conclusion
In patients with cervical spondylosis, intervertebral foraminotomy decompression resecting part of the UP can be performed. The safe range within the spinal column was up to 6.73 mm of width between the inferior vertebral end plate and the superior end plate in intervertebral space and up to 5.09 mm of depth from the medial border of UP to the lateral side at C3 to C7 without interfering with the spinal nerve root.
Abstract 4. Does body mass index affect outcomes after vertebral body tethering surgery?
Background
The objective of this study was to determine the effect of body weight and body mass index (BMI) on curve correction and on risk of postoperative complications after vertebral body tethering (VBT) surgery.
Methods
BMI in children has been defined as follows: underweight (< 5th percentile for age), normal (5th to 85th percentile) and overweight (> 85th percentile). This was a retrospective review of prospectively collected study group data. Patients with juvenile or adolescent idiopathic scoliosis with VBT with 2 years of follow-up from a multicentre early-onset scoliosis database were evaluated preoperatively, first erect, and at 2 years postoperatively. Analysis of variance was used to compare the 3 categories of BMI with significance as per Tukey–Kramer honestly significant difference post hoc test. Risk of scoliosis progression was analyzed with mid-P exact test.
Results
A total of 121 patients (51 underweight, 58 normal weight, 12 overweight; mean age 12.5 ± 1.6 yr; BMI 18.8 ± 4.6) were identified. After VBT, scoliosis improved over time (51° preoperatively, 29° 1st erect, 28° 2 yr postoperatively; p < 0.05). When we compared the underweight, normal and overweight groups, the mean preoperative age (13 yr, 13 yr, 12 yr), preoperative scoliosis (52°, 50°, 52°), preoperative kyphosis (29°, 28°, 33°), perioperative scoliosis correction (44%, 42%, 46%) and complications by 2 years follow-up (23%, 24%, 17%) were similar between the groups. There was 1 broken tether in each of the underweight and normal weight groups. Change in scoliosis percent correction from 1st erect to 2 years postoperatively was not significantly different between the groups; however, the risk ratio for scoliosis progression during this period was 4.74 (1.02–22.02, p = 0.04) for overweight patients.
Conclusion
Overweight patients treated with VBT had similar perioperative scoliosis correction and a similar risk of complications as compared with underweight and normal weight patients. Compared with other patients, overweight patients had a risk ratio of 4.7 for progression of scoliosis during the first 2 years postoperatively.
Abstract 5. Congenital kyphosis: progressive correction with an instrumented posterior epiphysiodesis
Background
Congenital kyphosis is a rare condition. In this case series we sought to identify the outcomes and complications of posterior instrumented fusion and the resultant epiphysiodesis effect in uniplanar congenital kyphosis in patients aged 5 years and under.
Methods
Patients were included if they were treated for a uniplanar congenital kyphotic deformity treated with posterior instrumented spinal fusion while aged under 5 years between October 2006 and August 2017, with a minimum of 2 years of follow-up. Patients were excluded if a coronal deformity greater than 10° was present.
Results
Six patients met the inclusion criteria. Mean age at surgery was 3.6 years. The mean kyphotic deformity before surgery was 49.7°. All patients underwent posterior instrumented fusion with autogenous iliac crest graft and a cast or brace postoperatively. One patient showed a loss of motor evoked potential on prone positioning, which returned to normal on supine positioning. No patient showed any postoperative neurologic deficits. One patient was diagnosed with a wound infection, which was successfully treated with oral antibiotics. By a follow-up of 5.4 years (range 2.2–10.9 yr) there was no failure of instrumentation. An epiphysiodesis effect (a difference of ≥ 5° in the kyphotic deformity measured between the immediate post-operative and final follow-up lateral whole spine x-ray) of 16.2° (range 7.2°–30.9°) was seen in 5 patients. The mean annual epiphysiodesis effect was 2.7° (95% confidence interval 1.4°–4.1°). No kyphosis proximal to the instrumentation was observed for the duration of follow-up.
Conclusion
Posterior instrumented fusion and epiphysiodesis is safe and effective. The epiphysiodesis effect occurs in 80% of cases, and the procedure is associated with an acceptable blood loss and a low incidence of neurologic complications.
Abstract 6. The use of halo gravity traction in severe, stiff scoliosis
Background
The correction of severe, stiff scoliosis in children is challenging because of the risks to the neural structures through acutely stretching the cord and its associated circulation. One method used to reduce the risk is preoperative halogravity traction (HGT) creating a gradual corrective force that is reversible if a patient’s condition deteriorates. In this study, we define the safety of HGT and characterize the chronology of the correction seen.
Methods
Consecutive pediatric patients with major curves exceeding 80° treated with HGT before definitive correction and posterior instrumented fusion were included. A standard traction protocol was employed in each case with the daily addition of weight until 50% of body weight force had been reached at 3 weeks. Traction remained in place until a neurologic complication or 6 weeks, whichever occurred sooner.
Results
A total of 24 patients were included with a mean age of 11.8 years. The majority of patients showed idiopathic deformities with major thoracic curves with a mean size of 122.5°, a deformity angular ration (DAR) of 16.7° and T1–L5 height of 234 mm. Mean duration of traction was 42 days with a mean improvement in height of 71.5 mm with 82.1% occurring over the first 3 weeks. The improvement in DAR reached 71.5% at 3 weeks. One patient showed a cranial nerve palsy prompting early surgery and 8 patients showed pin loosening, 1 of which required revision of their halo. One patient underwent a slower progression of traction because of urinary disturbance.
Conclusion
HGT is a safe treatment for severe, stiff scoliosis. It can respond to the patient’s neurologic status in real time. In contrast, acute intraoperative correction has a higher risk of neurologic injury because of the stretch applied to both the cord and spinal circulation. Eighty percent of the correction in spinal height and 70% of the angular correction occur in the first 3 weeks according to Hooke’s law, with the remaining 20% being due to a viscoelastic effect.
Abstract 7. Fusing to the pelvis in the correction of scoliosis associated with Rett syndrome
Background
Rett syndrome is a rare disorder characterized by severe scoliosis in 80% of cases. Posterior spinal fusion has been the mainstay of treatment. Fusing to the pelvis has been shown to influence the function of the spinopelvic relationship, which has been hypothesized to reduce the ability of these patients to ambulate. In this study, we show the results of the treatment of scoliosis in Rett syndrome and analyze the impact of fusing to the pelvis on ambulation.
Methods
A retrospective case series was used to analyze the radiographic, clinical and functional outcomes of consecutive patients treated for Rett syndrome scoliosis between the ages of 10 and 8 years in a single tertiary pediatric spinal unit. Cases were identified through departmental and neurophysiologic records, and patients were excluded if the diagnosis of Rett syndrome was not confirmed.
Results
Seven eligible cases were identified. The mean coronal Cobb angle was 90.9°, the mean sagittal Cobb angle was 72.0° and pelvic obliquity 24.5°. The mean postoperative improvement in coronal Cobb was 53.2° and pelvic obliquity was not significantly improved. These did not change during a mean follow-up of 2.7 years. None of the patients showed any postoperative complications and of the 4 patients fused to the pelvis, only 1 was able to ambulate preoperatively, and this ability was lost postoperatively.
Conclusion
Our data suggest that with modern technology, severe curves can be safely treated and that fusion to the pelvis is not necessary to prevent curve progression, which may be important in preserving patient mobility postoperatively.
Abstract 8. Tuberculosis of the craniovertebral junction: its altered biomechanics and treatment strategy
Background
We have designed a protocol-based management strategy for tuberculosis (TB) of the craniovertebral junction (CVJ). This study will assess functional outcomes of patients with CVJ Koch who were treated using this protocol.
Methods
A total of 108 patients with TB of the CVJ were managed at a tertiary care university hospital in India over a period of 12 years. Patients were divided radiologically into 3 grades depending on the severity of involvement. Patients were treated either conservatively or surgically using the treatment algorithm. Conservative management strategies included antituberculosis chemotherapy, orthosis and traction. Surgeries performed included occipitocervical fixation and fusion, transarticular screw fixation and fusion, C1–C2 separate fixation (pedicle screw, lateral mass screw, laminar screw).
Results
Sixty patients were treated conservatively, 28 patients required occipitocervical fusion, 18 patients needed transarticular screws and 2 patients were treated with C1–C2 separate fixation. Six patients had clinically appreciable tilt and 10 patients had axial settling in the conservatively treated group. However, there was no functional impairment. There was no neurologic deterioration in any conservatively treated patient. In the surgically treated group of 48 patients, not a single patient had neurologic deterioration. Out of the 8 patients who were clinically grade 3, 7 patients were ambulatory at 18 months follow-up. One patient remained paraplegic. Fusion was achieved in all cases.
Conclusion
Although the bacteria and the chemotherapy are the same, TB of the CVJ needs special attention because of the complex anatomy of the region and the presence of vital structures in the vicinity. Early detection, initial rigid orthosis for adequate healing and protocol-based surgical intervention when warranted will give a long-lasting fruitful outcome.
Abstract 9. Anatomic considerations and functional outcomes of endoscopic transiliac approach for access to L5–S1 disc and foramen
Background
Transforaminal endoscopic disc surgery has several advantages compared with open surgery. However, the efficacy of the procedure is in doubt when the conventional transforaminal approach is obstructed by anatomic barriers. One such difficult-to-access location is the L5–S1 disc. The purpose of the present study is to analyze the functional outcomes of endoscopic discectomy with the transiliac approach at the L5–S1 level and also provide details of the surgical technique.
Methods
This study was carried out over a period of 3 years (2015–2018) at a tertiary care spine hospital. Patients with a disc herniation at the L5–S1 level were classified as per the method described by the same authors that has been previously published. Only those patients requiring the transiliac approach were included in the study. To ensure no bias, all patients were operated by the same surgeon, who is also the lead author of this paper. We report the functional outcome data obtained during the 2-year postoperative follow-up period using visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores.
Results
Transforaminal endoscopic discectomy was performed through the transiliac approach in 62 patients. The VAS score improved, from 8.31 to 2.25 (p < 0.05). The ODI score also improved, from 70.23 to 17.71 (p < 0.05). No patient deteriorated neurologically, 1 patient had recurrence at the same level managed using selective nerve root block and 1 patient had recurrent disc herniation managed using the interlaminar approach.
Conclusion
Difficulty in using the transforaminal approach to the L5–S1 space is because of multiple anatomic barriers. Advantages of the transiliac approach include easy removal of central, foraminal or up-migrated disc fragment, no damage to the S1 end plate, reduced risk of injury to exiting nerve root, ease of foraminoplasty, and access to the epidural space. Transiliac endoscopic discectomy is safe and effective for lumbosacral disc pathologies. It can be performed with marking under fluoroscopy with simple orthopedic instruments under local anesthesia. It negates limitations of the transforaminal approach for the L5–S1 disc.
Abstract 10. Five-year revision rates for elective multilevel lumbar instrumented fusions in the elderly: an analysis of state databases
Background
Revisions following multilevel lumbar fusion surgery create substantial burden on patient quality of life and health care costs. We sought to evaluate 5-year revision rates as well as indications and modifiable risk factors for revisions following elective multilevel lumbar instrumented fusions in elderly patients.
Methods
Elderly patients (> 60 yr) who underwent multilevel (≥ 3) lumbar instrumented fusions, based upon International Classification of Diseases, 9th Revision (ICD-9) coding, were identified in the Healthcare Cost and Utilization Project (HCUP) state inpatient databases from Florida (2005–2014) and California (2005–2011). Operations for nonelective indications (i.e., fractures, tumour, infections) were excluded. Patients were followed for 5 years for subsequent revision operations and associated indications for revisions (degenerative disease [adjacent segment disease, spondylosis, degenerative disc disease], infection, mechanical failure [including pseudarthrosis], postlaminectomy syndrome, stenosis) using ICD-9 coding. Cox proportional hazards multivariate analyses were performed to determine risks associated with revisions for each diagnostic cause.
Results
A total of 5636 patients (3285 female; average age at index operation 71.6 yr) were included for analysis. For index operations, the majority were 3–7 levels (97.4%) and mean length of stay was 5.40 days. Overall 5-year revision rate was 16.5%. The most common causes of revision at 5 years were degenerative disease (DD) (50.7%), mechanical failure (32.2%) and stenosis (8.0%). Revision procedure coded at index operation was associated with increased risk of revision for DD (hazard ratio [HR] 1.59, 95% confidence interval [CI] 1.29–1.98, p < 0.001) and mechanical failure (HR 1.56, 95% CI 1.19–2.04, p = 0.020). Posterolateral spine fusion (PSF) and transforaminal lumbar interbody fusion (TLIF) plus PSF were associated with lower revision risk, compared with anterior lumbar interbody fusion (ALIF) plus PLF (PSF: HR 0.39, 95% CI 0.27–0.55, p < 0.001; TLIF + PSF: HR 0.56, 95% CI 0.40–0.79, p = 0.02). Male sex was associated with reduced revision risk for DD (HR 0.75, 95% CI 0.62–0.91, p = 0.04). Age, race, Charlson Comorbidity Index score, and physician and hospital fusion volumes had no effect on risk of revision.
Conclusion
Five-year revision rates were 16.5% following elective multilevel lumbar instrumented fusions in elderly patients. Degenerative disease and mechanical failure were the most common causes of revisions. These data may benefit preoperative counselling and shared decision-making of patients considering undergoing multilevel lumbar instrumented fusion.
Abstract 11. Lumbar PLIF without inpatient admission. Results of a standardized care protocol in over 100 selected patients treated over a 5-year period
Background
Resource limitations in health care argue for a continued evolution of “doing more with less.” The author’s hospital has set policy allowing for only 1 admitted scheduled care spine surgery case per day, which has potential to have an adverse impact on wait times and care. A standard care path used in decompression surgery was adapted to accommodate more invasive mono- and bi-segmental reconstructions starting in 2015 and has been followed forward comprehensively with a view to determining the success rate in managing these cases with only an overnight stay in the recovery room.
Methods
Qualifying cases were 1- and 2-level reconstructions in ambulatory patient