Publications by authors named "Jean-Marc Mac-Thiong"

173 Publications

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

J Pain 2021 Jul 21. Epub 2021 Jul 21.

International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada; Hugill Centre for Anesthesia, Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address:

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.
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http://dx.doi.org/10.1016/j.jpain.2021.06.013DOI Listing
July 2021

Are early clinical manifestations of spasticity associated with long-term functional outcome following spinal cord injury? A retrospective study.

Spinal Cord 2021 Jul 6. Epub 2021 Jul 6.

Research Center, Centre intégré universitaire de santé et services sociaux du Nord-de-l'Île-de-Montréal (Hopital du Sacré-Coeur de Montréal), Montreal, QC, H4J 1C5, Canada.

Study Design: Retrospective study of a prospective cohort of patients with traumatic spinal cord injury (SCI).

Objectives: Determine the relationship between the occurrence of early spasticity, defined as the development of signs and/or symptoms of spasticity during the hospitalization in traumatology, and the functional outcome 6-12 months following a SCI. Secondly, to determine the specific impact of early clonus, velocity-dependent hypertonia and/or muscle spasms on the functional outcome at the same timepoint.

Setting: Single trauma center specialized in SCI care.

Methods: One hundred sixty-two patients sustaining an acute traumatic SCI were included in the analyses. Comparative analysis was performed to describe the characteristics of patients with early spasticity. Correlations were performed to determine the relationship between the clinical signs of spasticity and the Spinal Cord Independence Measure (SCIM) scores collected 6-12 months after SCI.

Results: 51.9% of the cohort developed clinical signs of spasticity during the hospitalization in traumatology (29.7 days) following SCI. These showed a significantly lower total SCIM score and subscores compared to individuals without early spasticity at follow-up (p < 0.05). After adjusting for confounding factors, the occurrence of early spasms was only clinical sign of spasticity significantly associated with a decreased mobility at follow-up (r = -0.17, p = 0.04).

Conclusions: The development of signs and symptoms of spasticity, in particular the occurrence of spasms in the first month following the injury may be associated with decreased functional outcome and mobility. Early assessment of spasticity following SCI is thus recommended.
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http://dx.doi.org/10.1038/s41393-021-00661-1DOI Listing
July 2021

Early Predictors of Neurological Outcomes After Traumatic Spinal Cord Injury: A Systematic Review and Proposal of a Conceptual Framework.

Am J Phys Med Rehabil 2021 07;100(7):700-711

From the Hôpital du Sacré-Cœur de Montréal, Montreal, Quebec, Canada (PMM, AR-D, J-MM-T); Department of Surgery, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada (MB, J-MM-T); Sainte-Justine University Hospital Research Center, Montreal, Quebec, Canada (MB, J-MM-T); Department of Community Health Sciences, Faculty of Medicine and Health Sciences, Centre de recherche Charles-Le Moyne Saguenay-Lac-St-Jean sur les innovation de santé, Université de Sherbrooke, Longueuil, Quebec, Canada (MB); and Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada (AR-D).

Background: Neurological outcomes after traumatic spinal cord injury are variable and depend on patient-, trauma-, and treatment-related factors as well as on spinal cord injury characteristics, imaging, and biomarkers.

Objective: The aims of the study were to identify and classify the early predictors of neurological outcomes after traumatic spinal cord injury.

Data Sources: The Medline, PubMed, Embase, and the Cochrane Central Database were searched using medical subject headings. The search was extended to the reference lists of identified studies.

Study Eligibility Criteria: The study eligibility criteria were assessment of neurological outcomes as primary or secondary outcome, predictors collected during the acute phase after traumatic spinal cord injury, and multivariate design.

Participants: The participants were adult patients with traumatic spinal cord injury followed at least 3 mos after injury.

Study Appraisal And Synthesis Methods: The quality of studies was assessed by two independent reviewers using the Study Quality Assessment Tools for Observational Cohort and Cross-sectional Studies. The studies' narrative synthesis relied on a classification of the predictors according to quantity, quality, and consistency of the evidence. Results were summarized in a conceptual framework.

Results: Forty-nine articles were included. The initial severity of traumatic spinal cord injury (American Spinal Injury Association Impairment Scale, motor score, and neurological level of injury) was the strongest predictor of neurological outcomes: patients with more severe injury at admission presented poor neurological outcomes. Intramedullary magnetic resonance imaging signal abnormalities were also associated with neurological outcomes, as the presence of intramedullary hemorrhage was a factor of poor prognosis. Other largely studied predictors, such as age and surgical timing, showed some inconsistency in results depending on cutoffs. Younger age and early surgery were generally associated with good outcomes. Although widely studied, other factors, such as vertebral and associated injuries, failed to show association with outcomes. Cerebrospinal fluid inflammatory biomarkers, as emerging factors, were significantly associated with outcomes.

Conclusions: This study provides a comprehensive review of predictors of neurological outcomes after traumatic spinal cord injury. It also highlights the heterogeneity of outcomes used by studies to assess neurological recovery. The proposed conceptual framework classifies predictors and illustrates their relationships with outcomes.
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http://dx.doi.org/10.1097/PHM.0000000000001701DOI Listing
July 2021

Proteomic Portraits Reveal Evolutionarily Conserved and Divergent Responses to Spinal Cord Injury.

Mol Cell Proteomics 2021 Jun 12;20:100096. Epub 2021 Jun 12.

Division of Neurosurgery, University of British Columbia, Vancouver, British Columbia, Canada.

Despite the emergence of promising therapeutic approaches in preclinical studies, the failure of large-scale clinical trials leaves clinicians without effective treatments for acute spinal cord injury (SCI). These trials are hindered by their reliance on detailed neurological examinations to establish outcomes, which inflate the time and resources required for completion. Moreover, therapeutic development takes place in animal models whose relevance to human injury remains unclear. Here, we address these challenges through targeted proteomic analyses of cerebrospinal fluid and serum samples from 111 patients with acute SCI and, in parallel, a large animal (porcine) model of SCI. We develop protein biomarkers of injury severity and recovery, including a prognostic model of neurological improvement at 6 months with an area under the receiver operating characteristic curve of 0.91, and validate these in an independent cohort. Through cross-species proteomic analyses, we dissect evolutionarily conserved and divergent aspects of the SCI response and establish the cerebrospinal fluid abundance of glial fibrillary acidic protein as a biochemical outcome measure in both humans and pigs. Our work opens up new avenues to catalyze translation by facilitating the evaluation of novel SCI therapies, while also providing a resource from which to direct future preclinical efforts.
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http://dx.doi.org/10.1016/j.mcpro.2021.100096DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260874PMC
June 2021

Clinical judgment is a cornerstone for validating and using clinical prediction rules: a head-to-head study on ambulation outcomes for spinal cord injured patients.

Spinal Cord 2021 May 7. Epub 2021 May 7.

Université de Montréal, Faculty of Medicine, Montréal, QC, Canada.

Study Design: Retrospective comparative study.

Objective: Clinical prediction rules (CPRs) are an effervescent topic in the medical literature. Recovering ambulation after a traumatic spinal cord injury (tSCI) is a priority for patients and multiple CPRs have been proposed for predicting ambulation outcomes. Our objective is to confront clinical judgment to an established CPR developed for patients with tSCI.

Settings: Level one trauma center specialized in tSCI and its affiliated rehabilitation center.

Method: In this retrospective comparative study, six physicians had to predict the ambulation outcome of 68 patients after a tSCI based on information from the acute hospitalization. Ambulation was also predicted according to the CPR of van Middendorp (CPR-vM). The success rate of the CPR-vM and clinicians to predict ambulation was compared using criteria of 5% for defining clinical significance, and a level of statistical significance of 0.05 for bilateral McNemar tests.

Results: There was no statistical difference between the overall performance of physicians (success rate of 79%) and of the CPR-vM (81%) for predicting ambulation. The differences between the CPR-vM and physicians varied clinically and significantly with the level of experience, clinical setting, and field of expertise.

Conclusion: Confronting CPRs with the judgment of a group of clinicians should be an integral part of the design and validation of CPRs. Head-to-head comparison of CPRs with clinicians is also a cornerstone for defining the optimal strategy for translation into the clinical practice, and for defining which clinician and specific clinical context would benefit from using the CPR.
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http://dx.doi.org/10.1038/s41393-021-00632-6DOI Listing
May 2021

Assessing head acceleration to identify a motor threshold to galvanic vestibular stimulation.

J Neurophysiol 2021 Jun 21;125(6):2191-2205. Epub 2021 Apr 21.

School of Rehabilitation, Université de Montréal, Montreal, Canada.

Galvanic vestibular stimulation (GVS) is used to assess vestibular system function, but vestibulospinal responses can exhibit variability depending on protocols or intensities used. Here, we measured head acceleration in healthy subjects to identify an objective motor threshold on which to base GVS intensity when assessing standing postural responses. Thirteen healthy right-handed subjects stood on a force platform, eyes closed, and head facing forward. An accelerometer was placed on the vertex to detect head acceleration, and electromyography activity of the right soleus was recorded. GVS (200 ms; current steps 0.5, from 1 mA to 4 mA) was applied in a binaural and bipolar configuration. ) GVS induced a biphasic accelerometer response at a latency of 15 ms. Based on response amplitude, we constructed a recruitment curve for all participants and determined the motor threshold. In parallel, the method of limits was used to devise a more rapid approach to determine motor threshold. ) We observed significant differences between motor threshold based on a recruitment curve and all perceptual thresholds reported either by the subject (sensation of movement) or a standing experimenter observing the participant (perception of movement). No significant difference was observed between the motor threshold based on the method of limits and perceptual thresholds of movement. ) Using orthogonal polynomial contrasts, we observed a linear progression between multiples of the objective motor threshold (0.5, 0.75, 1, 1.5× motor threshold) and the 95% confidence ellipse area, the first peak of center of pressure displacement velocity, and the short and medium latency responses in the soleus. Hence, an objective motor threshold for GVS based on head acceleration was identified in standing participants and a recruitment curve could be constructed for all participants. These novel approaches could enable better understanding of changes in the vestibular system in different conditions or over time. Galvanic vestibular stimulation (GVS) has been used to assess the vestibular system, but the significant interindividual variability in the responses makes it difficult to quantitatively compare them between individuals or conditions. Using an accelerometer to quantify head movement induced by GVS, we were able to determine an objective motor threshold and construct a recruitment curve for all participants. These methods could help assess changes in the vestibular system under different conditions.
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http://dx.doi.org/10.1152/jn.00254.2020DOI Listing
June 2021

An evaluation of the representativeness of a national spinal cord injury registry: a population-based cohort study.

Spinal Cord 2021 Apr 7. Epub 2021 Apr 7.

Hôpital du Sacré-Cœur de Montréal, Montréal, QC, Canada.

Study Design: Population-based cohort study for the western part of Quebec.

Objectives: To determine the impact of declining to participate in a national spinal cord injury (SCI) registry on patient outcomes and continuum of care.

Setting: Level-1 trauma center specialized in SCI care in Montreal, Canada.

Methods: This cohort study compared the outcomes of 444 patients who were enrolled in the Rick Hansen SCI registry and 140 patients who refused. Logistic regression analyses were performed to assess the association between voluntary participation and the outcomes, while adjusting for confounding factors. The main outcomes were: attendance to follow-up 6- to 12-month post injury, 1-year mortality, and the occurrence of pressure injury during acute care.

Results: Declining to be enrolled in the registry was a significant predictor of lower attendance to specialized follow-up (adjusted odds ratio [OR] 0.04, 95% confidence interval [CI] 0.02-0.08). It was also associated with a higher 1-year mortality rate (OR 12.50, CI 4.50-33.30) and higher occurrence of pressure injury (OR 2.56, CI 1.56-4.17).

Conclusions: This study sheds invaluable insight on individuals that researchers and clinicians are usually blind to in SCI cohort studies. This study suggests that decline to participate in a registry during the care hospitalization may be associated with worsened health, poorer outcomes, and reduced follow-up to specialized care. Declining the enrollment to voluntary registry could represent a potential prognostic factor for future research.
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http://dx.doi.org/10.1038/s41393-021-00622-8DOI Listing
April 2021

A Sensitive and Fast Fiber Bragg Grating-Based Investigation of the Biomechanical Dynamics of In Vitro Spinal Cord Injuries.

Sensors (Basel) 2021 Mar 1;21(5). Epub 2021 Mar 1.

École de Technologie Supérieure, 1100 Notre-Dame Street West, Montreal, QC H3C 1K3, Canada.

To better understand the real-time biomechanics of soft tissues under sudden mechanical loads such as traumatic spinal cord injury (SCI), it is important to improve in vitro models. During a traumatic SCI, the spinal cord suffers high-velocity compression. The evaluation of spinal canal occlusion with a sensor is required in order to investigate the degree of spinal compression and the fast biomechanical processes involved. Unfortunately, available techniques suffer with drawbacks such as the inability to measure transverse compression and impractically large response times. In this work, an optical pressure sensing scheme based on a fiber Bragg grating and a narrow-band filter was designed to detect and demonstrate the transverse compression inside a spinal cord surrogate in real-time. The response time of the proposed scheme was 20 microseconds; a five orders of magnitude enhancement over comparable schemes that depend on costly and slower optical spectral analyzers. We further showed that this improvement in speed comes with a negligible loss in sensitivity. This study is another step towards better understanding the complex biomechanics involved during a traumatic SCI, using a method capable of probing the related internal strains with high-spatiotemporal resolution.
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http://dx.doi.org/10.3390/s21051671DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7957506PMC
March 2021

Finite element assessment of a disc-replacement implant for treating scoliotic deformity.

Clin Biomech (Bristol, Avon) 2021 Apr 17;84:105326. Epub 2021 Mar 17.

Department of Neurosurgery, University of Virginia, Charlottesville, VA 22903, USA; Department of Neurosurgery, Children's National Hospital, Washington, DC 20010, USA. Electronic address:

Background: Bracing and spinal fusion surgery have long been the primary methods for idiopathic scoliosis correction; however, there exist multiple limitations with both techniques. Growth modulation techniques have recently been attempted, but are typically performed across multiple vertebral elements. The aim of this study was to quantify the corrective abilities of a dual-angled, wedge shaped, rigid disc implant designed to correct spinal deformity.

Methods: The 3D spinal geometry of four patients was reconstructed using calibrated radiographs, from which personal finite element models were created. Coronal and sagittal Cobb angles and axial stress distribution were calculated pre- and post- simulation of device implantation at the apical vertebral element.

Findings: Insertion of a rigid wedged implant resulted in up to 90.1% coronal correction with kyphotic normalization, and reduced axial stress differential within adjacent vertebrae by up to 83.3%. This correction in axial stress differential was seen to propagate to subjacent vertebrae in both rostral and caudal directions. Insertion of two implants yielded greater correction with respect to all three measures.

Interpretation: Local Cobb angle correction, increased kyphotic angle, and a decrease in axial stress differential with adjacent and subjacent vertebral levels demonstrate a potential for deformity correction from within the disc space. The decrease in axial stress differential demonstrates a capacity for growth modulation and reversal of the Heuter-Volkmann principle. Based on qualitative views of spinal shape following device implantation, the wedged implant proved more efficacious in correcting single thoracic curves than double major curves.
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http://dx.doi.org/10.1016/j.clinbiomech.2021.105326DOI Listing
April 2021

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

J Neurotrauma 2021 May 3. Epub 2021 May 3.

International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada.

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.
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http://dx.doi.org/10.1089/neu.2020.7352DOI Listing
May 2021

Real-time biomechanics using the finite element method and machine learning: Review and perspective.

Med Phys 2021 Jan 7;48(1):7-18. Epub 2020 Dec 7.

ETS Montreal, University of Quebec, 1100 Notre-Dame West, Montreal, QC, Canada.

Purpose: The finite element method (FEM) is the preferred method to simulate phenomena in anatomical structures. However, purely FEM-based mechanical simulations require considerable time, limiting their use in clinical applications that require real-time responses, such as haptics simulators. Machine learning (ML) approaches have been proposed to help with the reduction of the required time. The present paper reviews cases where ML could help to generate faster simulations, without considerably affecting the performance results.

Methods: This review details the ML approaches used, considering the anatomical structures involved, the data collection strategies, the selected ML algorithms, with corresponding features, the metrics used for validation, and the resulting time gains.

Results: A total of 41 references were found. ML algorithms are mainly trained with FEM-based simulations in 32 publications. The preferred ML approach is neural networks, including deep learning in 35 publications. Tissue deformation is simulated in 18 applications, but other features are also considered. The average distance error and mean squared error are the most frequently used performance metrics, in 14 and 17 publications, respectively. The time gains were considerable, going from hours or minutes for purely FEM-based simulations to milliseconds, when using ML.

Conclusions: ML algorithms can be used to accelerate FEM-based biomechanical simulations of anatomical structures, possibly reaching real-time responses. Fast and real-time simulations of anatomical structures, generated with ML algorithms, can help to reduce the time required by FEM-based simulations and accelerate their adoption in the clinical practice.
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http://dx.doi.org/10.1002/mp.14602DOI Listing
January 2021

Clinical Protocol for Identifying and Managing Bladder Dysfunction during Acute Care after Traumatic Spinal Cord Injury.

J Neurotrauma 2021 Mar 3;38(6):718-724. Epub 2020 Dec 3.

Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada.

Bladder dysfunction is widespread following traumatic spinal cord injury (TSCI). Early diagnosis of bladder dysfunction is crucial in preventing complications, determining prognosis, and planning rehabilitation. We aim to suggest the first clinical protocol specifically designed to evaluate and manage bladder dysfunction in TSCI patients during acute care. A retrospective cohort study was conducted on 101 patients admitted for an acute TSCI between C1 and T12. Following spinal surgery, presence of voluntary anal contraction (VAC) was used as a criterion for removal of indwelling catheter and initiating trial of void (TOV). Absence of bladder dysfunction was determined from three consecutive post-void bladder scan residuals ≤200 mL without incontinence. All patients were reassessed 3 months post-injury using the Spinal Cord Independence Measure (SCIM). A total of 74.3% were diagnosed with bladder dysfunction during acute care, while 57.4% had a motor-complete TSCI. Three months later, 94.7% of them reported impaired bladder function. None of the patients discharged from acute care after a functional bladder was diagnosed reported impaired bladder function at the 3-month follow-up. A total of 95.7% patients without VAC had persisting impaired bladder function at follow-up. The proposed protocol is specifically adapted to the dynamic nature of neurogenic bladder function following TSCI. The assessment of VAC into the protocol provides major insight on the potential for reaching adequate bladder function during the subacute phase. Conducting TOV using bladder scan residuals in patients with VAC is a non-invasive and easy method to discriminate between a functional and an impaired bladder following acute TSCI.
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http://dx.doi.org/10.1089/neu.2020.7190DOI Listing
March 2021

Building models for prediction: are we good at it?

Spinal Cord 2020 11 13;58(11):1147-1149. Epub 2020 Oct 13.

Department of Surgery, Faculty of Medicine, University of Montreal, Montreal, QC, Canada.

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http://dx.doi.org/10.1038/s41393-020-00563-8DOI Listing
November 2020

Factors associated with discharge destination following inpatient functional rehabilitation in patients with traumatic spinal cord injury.

Spinal Cord 2021 Jun 5;59(6):642-648. Epub 2020 Sep 5.

Faculty of Medicine, University of Montreal, Pavillon Roger-Gaudry, S-749, C.P. 6128, succ. Centre-ville, Montreal, QC, H3C 3J7, Canada.

Study Design: Retrospective review of data from a prospective database of a Level 1 trauma center.

Objectives: This project aims to identify factors collected during the acute and rehabilitative care following a traumatic spinal cord injury (TSCI) associated with success and failure to return home after inpatient intensive functional rehabilitation (IFR).

Setting: Level 1 trauma center specialized in TSCI care in Montreal, Canada.

Methods: All eligible patients from our prospective database were separated into two groups according to discharge destination following IFR. Clinical variables collected during the acute and rehabilitative care as well as demographic variables were compared between patients who managed to return home (Group 1) and those who were discharged elsewhere (Group 2). Multivariable regression analyses were conducted with variables that were significant at the univariate level.

Results: Out of the 193 patients included, 22 (11%) failed to return home following IFR. Six variables were associated with failure to return home at the univariate level: longer acute length of stay (LOS), longer rehabilitation LOS, living alone, higher neurological level of injury, having comorbidities, and having a pressure injury (PI) during acute care. Three variables remained significant at the multivariate level: living alone, increasing acute LOS and presenting a high cervical (C1-C4) neurological level of injury.

Conclusions: It is important that acute care clinicians recognize the aforementioned factors early after TSCI in order to optimize patients for community reintegration.
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http://dx.doi.org/10.1038/s41393-020-00542-zDOI Listing
June 2021

Patient outcomes in idiopathic scoliosis are associated with biological endophenotypes: 2020 SOSORT award winner.

Eur Spine J 2021 05 29;30(5):1125-1131. Epub 2020 Aug 29.

Viscogliosi Laboratory in Molecular Genetics of Musculoskeletal Diseases, Sainte-Justine University Hospital Research Center, Université de Montréal, Montreal, QC, Canada.

Purpose: Bracing is the treatment of choice for idiopathic scoliosis (IS), unfortunately factors underlying brace response remain unknown. Clinicians are currently unable to identify patients who may benefit from bracing, and therefore, better molecular stratification is critically needed. The aim of this study is to evaluate IS patient outcomes at skeletal maturity in relation to biological endophenotypes, and determine specific endophenotypes associated to differential bracing outcomes. This is a retrospective cohort with secondary cross-sectional comparative studies.

Methods: Clinical and radiological data were collected from 563 IS patients, stratified into biological endophenotypes (FG1, FG2, FG3) based on a cell-based test. Measured outcomes were maximum Cobb angle at skeletal maturity, and if severe, spinal deformity (≥ 45°) or surgery was attained. Treatment success/failure was determined by standard progression thresholds (Cobb ≥ 45° or surgery; Cobb angle progression ≥ 6°). Multivariable analyses were performed to evaluate associations between endophenotypes and clinical outcome.

Results: Higher Cobb angles at maturity for FG1 and FG2 patients were observed (p = 0.056 and p = 0.05), with increased likelihood of ≥ 45° and/or surgery for FG1 (OR = 2.181 [1.002-4.749] and FG2 (OR = 2.141 [1.038-4.413]) compared to FG3. FG3 was 9.31 [2.58-33.61] and 5.63 [2.11-15.05] times more likely for bracing success at treatment termination and based on the < 6° progression criterion, respectively, compared to FG1.

Conclusion: Associations between biological endophenotypes and outcomes suggest differences in progression and/or bracing response among IS patients. Outcomes were most favorable in FG3 patients. The results pave the way for establishing personalized treatments, distinguishing who may benefit or not from treatment.
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http://dx.doi.org/10.1007/s00586-020-06579-1DOI Listing
May 2021

In-Hospital Mortality for the Elderly with Acute Traumatic Spinal Cord Injury.

J Neurotrauma 2020 11 26;37(21):2332-2342. Epub 2020 Aug 26.

Department of Orthopaedics, Vancouver Spine Surgery Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.

As the incidence of traumatic spinal cord injury (tSCI) in the elderly rises, clinicians are increasingly faced with difficult discussions regarding aggressiveness of management, likelihood of recovery, and survival. Our objective was to outline risk factors associated with in-hospital mortality in elderly surgical and non-surgical patients following tSCI and to determine those unlikely to have a favorable outcome. Data from elderly patients (≥ 65 years of age) in the Canadian Rick Hansen SCI Registry from 2004 to 2017 were analyzed using descriptive analysis. Survival and mortality groups in each of the surgical and non-surgical group were compared to explore factors associated with in-hospital mortality and their impact, using logistical regression. Of 1340 elderly patients, 1018 had surgical data with 826 having had surgery. In the surgical group, the median time to death post-injury was 30 days with 75% dying within 50 days compared with 7 days and 20 days, respectively, in the non-surgical group. Significant predictors for in-hospital mortality following surgery are age, comorbidities, neurological injury severity (American Spinal Injury Association [ASIA] Impairment Scale [AIS]), and ventilation status. The odds of dying 50 days post-surgery are six times higher for patients ≥77 years of age versus those 65-76 years of age, five times higher for those with AIS A versus those with AIS B/C/D, and seven times higher for those who are ventilator dependent. An expected probability of dying within 50 days post-surgery was determined using these results. In-hospital mortality in the elderly after tSCI is high. The trend with age and time to death and the significant predictors of mortality identified in this study can be used to inform clinical decision making and discussions with patients and their families.
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http://dx.doi.org/10.1089/neu.2019.6912DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7585611PMC
November 2020

Opioid Poisoning and Opioid Use Disorder in Older Trauma Patients.

Clin Interv Aging 2020 27;15:763-770. Epub 2020 May 27.

Centre d'Étude en Médecine d'Urgence, Hôpital du Sacré-Coeur de Montréal, Montréal, Quebec, Canada.

Background: Patients hospitalized following a traumatic injury will be frequently treated with opioids during their stay and after discharge. We examined the relationship between acute phase (<3 months) opioid use after discharge and the risk of opioid poisoning or use disorder in older trauma patients.

Methods: In a retrospective multicenter cohort study conducted on registry data, we included all patients ≥65 years admitted (hospital stay >2 days) for injury in 57 trauma centers in the province of Quebec (Canada) between 2004 and 2014. We searched for opioid poisoning and opioid use disorder from ICD-9 to ICD-10 code diagnosis after their initial injury. Patients that filled an opioid prescription within a 3-month period after sustaining the trauma were compared to those who did not, using Cox proportional hazards regressions.

Results: A total of 70,314 admissions were retained for analysis; median age was 82 years (IQR: 75-87), 68% were women, and 34% of the patients filled an opioid prescription within 3 months of the initial trauma. During a median follow-up of 2.6 years (IQR: 1-5), 192 participants (0.27%; 95% CI: 0.23%-0.31%) were hospitalized for opioid poisoning and 73 (0.10%; 95% CI: 0.08%-0.13%) were diagnosed with opioid use disorder. Having filled an opioid prescription within 3 months of injury was associated with an increased hazard ratio of opioid poisoning (2.8; 95% CI: 2.1-3.8) and opioid use disorder (4.2; 95% CI: 2.4-7.4) after the injury. However, history of opioid poisoning (2.6; 95% CI: 1.1-5.8), of substance use disorder (4.3; 95% CI: 2.4-7.7), or of the opioid prescription filled (2.8; 95% CI: 2.2-3.6) before the trauma, was also related to opioid poisoning or opioid use disorder after the injury.

Conclusion: Opioid poisoning and opioid use disorder are rare events after hospitalization for trauma in older patients. However, opioids should be used cautiously in patients with a history of substance use disorder, opioid poisoning or opioid use.
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http://dx.doi.org/10.2147/CIA.S252849DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7266327PMC
November 2020

Contribution of injured posterior ligamentous complex and intervertebral disc on post-traumatic instability at the cervical spine.

Comput Methods Biomech Biomed Engin 2020 Sep 28;23(12):832-843. Epub 2020 May 28.

Department of Mechanical Engineering, Ecole de technologie superieure, Montreal, Canada.

Posterior ligamentous complex (PLC) and intervertebral disc (IVD) injuries are common cervical spine flexion-distraction injuries, but the residual stability following their disruption is misknown. The objective of this study was to evaluate the effect of PLC and IVD disruption on post-traumatic cervical spine stability under low flexion moment (2 Nm) using a finite element (FE) model of C2-T1. The PLC was removed first and a progressive disc rupture (one third, two thirds and complete rupture) was modeled to simulate IVD disruption at C2-C3, C4-C5 and C6-C7. At each step, a non-traumatic flexion moment was applied and the change in stability was evaluated. PLC removal had little impact at C2-C3 but increased local range of motion (ROM) at the injured level by 77.2% and 190.7% at C4-C5 and C6-C7, respectively. Complete IVD rupture had the largest impact on C2-C3, increasing C2-C3 ROM by 181% and creating a large antero-posterior displacement of the C2-C3 segment. The FE analysis showed PLC and disc injuries create spinal instability. However, the PLC played a bigger role in the stability of the middle and lower cervical spine while the IVD was more important at the upper cervical spine. Stabilization appears important when managing patients with soft tissue injuries.
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http://dx.doi.org/10.1080/10255842.2020.1767776DOI Listing
September 2020

Morphological features of thoracolumbar burst fractures associated with neurological outcome in thoracolumbar traumatic spinal cord injury.

Eur Spine J 2020 10 19;29(10):2505-2512. Epub 2020 May 19.

Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.

Purpose: To identify specific morphological characteristics in thoracolumbar burst fractures associated with neurological outcome after severe traumatic spinal cord injury (TSCI).

Methods: We retrospectively analyzed the clinical and radiological (CT scan morphological characteristics) data of 25 consecutive patients admitted for TSCI secondary to a burst fracture at levels from T11 to L2 between 2010 and 2017 in single level-1 trauma center. We included severe TSCI, defined as American Spinal Injury Association Impairment Scale (AIS) grade A, B or C.

Results: Among the 25 patients with severe TSCI, 14 were AIS A, 5 were AIS B, and 6 were AIS C upon initial preoperative neurological evaluation. The AIS grade and the burden of associated injuries (Injury Severity Score, ISS) were the only clinical factors significantly associated with poor neurological recovery. The trauma level of energy was not associated with neurological outcome. Several fractures parameters were independently related to neurological recovery: the postero-inferior corner translation, presence of retropulsed fragment comminution and complete lamina fracture. The magnitude of sagittal kyphosis angle, vertebral kyphosis index and vertebral body comminution were not associated with the neurological outcome.

Conclusions: Morphological features of the bony structures involving the spinal canal in thoracolumbar burst fractures with severe TSCI are associated with the chronic neurological outcome and could provide more insight than the AIS clinical grading. The fracture pattern may better reflect the actual level of energy transferred to the spinal cord than distinguishing between low- and high-energy trauma.
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http://dx.doi.org/10.1007/s00586-020-06420-9DOI Listing
October 2020

Numerical investigation of the relative effect of disc bulging and ligamentum flavum hypertrophy on the mechanism of central cord syndrome.

Clin Biomech (Bristol, Avon) 2020 04 18;74:58-65. Epub 2020 Feb 18.

Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; International Laboratory on Spine Imaging and Biomechanics (iLab-Spine), France. Electronic address:

Background: The pathogenesis of the central cord syndrome is still unclear. While there is a consensus on hyperextension as the main traumatic mechanism leading to this condition, there is yet to be consensus in studies regarding the pathological features of the spine (intervertebral disc bulging or ligamentum flavum hypertrophy) that could contribute to clinical manifestations.

Methods: A comprehensive finite element model of the cervical spine segment and spinal cord was used to simulate high-speed hyperextension. Four stenotic cases were modelled to study the effect of ligamentum flavum hypertrophy and intervertebral disc bulging on the von Mises stress and strain.

Findings: During hyperextension, the downward displacement of the ligamentum flavum and a reduction of the spinal canal diameter (up to 17%) led to a dynamic compression of the cord. Ligamentum flavum hypertrophy was associated with stress and strain (peak of 0.011 Mpa and 0.24, respectively) in the lateral corticospinal tracts, which is consistent with the histologic pattern of the central cord syndrome. Linear intervertebral disc bulging alone led to a higher stress in the anterior and posterior funiculi (peak 0.029 Mpa). Combined with hypertrophic ligamentum flavum, it further increased the stress and strain in the corticospinal tracts and in the posterior horn (peak of 0.023 Mpa and 0.35, respectively).

Interpretation: The stenotic typology and geometry greatly influence stress and strain distribution resulting from hyperextension. Ligamentum flavum hypertrophy is a main feature leading to central cord syndrome.
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http://dx.doi.org/10.1016/j.clinbiomech.2020.02.008DOI Listing
April 2020

Decreasing pressure injuries and acute care length of stay in patients with acute traumatic spinal cord injury.

J Spinal Cord Med 2020 Feb 11:1-9. Epub 2020 Feb 11.

Faculty of Medicine, Department of Medicine, University of Montreal, Montreal, Quebec, Canada.

Identifying factors associated with the occurrence of pressure injuries (PI) during acute care and with longer length of stay (LOS), focusing on modifiable factors that can be addressed and optimized by the acute rehabilitation team. Prospective cohort study. A single Level-1 trauma center specialized in SCI care. A cohort of 301 patients with acute TSCI was studied. The primary outcome was the occurrence of PI during acute care stay. The secondary outcome was acute care LOS. Bivariate and multivariate logistic or linear regression analyses were performed to determine the association between non-modifiable factors and outcomes (PI of any stage and acute LOS), whereas bivariate and hierarchical multivariate logistic or linear regression analyses were used for modifiable factors. When controlling for the level and severity of the TSCI, the occurrence of pneumonia (OR = 2.1, CI = 1.1-4.1) was significantly associated with the occurrence of PI. When controlling for the level and severity of the TSCI, the occurrence of medical complications (PI, urinary tract infection and pneumonia) and lesser daily therapy resulted in significantly longer acute care LOS (P < .001). Prevention of PI occurrence and the optimization of the acute care LOS represent crucial challenges of the acute rehabilitation team, as they are significantly associated with higher functional outcomes. Patients who develop pneumonia may benefit from more aggressive prevention strategies to reduce PI occurrence. Systematic protocols for the prevention of complications as well as greater volume of therapy interventions should be considered to optimize the acute care LOS.
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http://dx.doi.org/10.1080/10790268.2020.1718265DOI Listing
February 2020

The Functional Impact of the Absence of a Bulbocavernosus Reflex in the Postoperative Period After a Motor-Complete Traumatic Spinal Cord Injury.

Am J Phys Med Rehabil 2020 08;99(8):712-718

From the Faculty of Medicine, Department of Medicine, University of Montreal, Montreal, Quebec, Canada (NG, B-HN, AR-D); Hôpital du Sacré-Cœur de Montréal, Montreal, Quebec, Canada (J-MM-T, AR-D); Sainte-Justine University Hospital Research Center, Montréal, Quebec, Canada (J-MM-T); Faculty of Medicine, Department of Surgery, University of Montreal, Montreal, Quebec, Canada (J-MM-T); and Institut de réadaptation Gingras-Lindsay de Montréal, Montréal, Quebec, Canada (B-HN).

Objective: The aim of the study was to investigate the impact of the absence of a bulbocavernosus reflex in the postoperative period on the neurological and functional recovery 6-12 mos after a motor-complete traumatic spinal cord injury.

Design: A retrospective review of a prospective database was completed among 66 patients. The functional and neurological statuses between individuals with and without a bulbocavernosus reflex were compared. A general linear model was used to investigate the association between the postoperative bulbocavernosus reflex status and the functional outcome, using the Spinal Cord Independence Measure.

Results: Forty percent of the cohort had no bulbocavernosus reflex 5 days after trauma. Individuals with a bulbocavernosus reflex showed a higher rate of American Spinal Injury Association Impairment Scale grade conversion, improvement of the level of injury, and higher functional scores; however, it did not reach a significant level. The bulbocavernosus reflex status in the postoperative period was not significantly associated with the functional status 6-12 mos after injury.

Conclusions: Late recovery of the bulbocavernosus reflex in the postoperative period may be associated with poorer neurological and functional outcome for individuals sustaining a motor-complete traumatic spinal cord injury, for which the prognosis estimation is limited. A prospective study including a larger number of patients is necessary to confirm results of this study.
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http://dx.doi.org/10.1097/PHM.0000000000001398DOI Listing
August 2020

Towards a new 3D classification for adolescent idiopathic scoliosis.

Spine Deform 2020 06 5;8(3):387-396. Epub 2020 Feb 5.

CHU Sainte-Justine, Montréal, Canada.

Study Design: Retrospective analysis of consecutive cases.

Objectives: To identify clinically relevant three-dimensional (3D) sub-groups for adolescent idiopathic scoliosis (AIS). Classifications for AIS are developed to assist surgeons in surgical planning and therapeutic management. However, current systems are based on two-dimensional (2D) parameters that do not completely describe the 3D deformity. Hence, variations in surgical results based on pre-operative 2D classifications may be attributed to the lack of 3D description.

Methods: Subjects from a multicenter database of AIS patients were included in this study. All patients had bi-planar radiographs and 3D reconstruction of the entire spine. A clustering algorithm based on fuzzy c-means was utilized to identify sub-groups based on the following ten parameters measured on 3D reconstructions of the spine: Cobb angle, orientation of the plane of maximum curvature of the proximal thoracic, mid-thoracic (MT) and thoracolumbar (TLL) levels, axial rotation of the apical vertebra of the MT and TLL segments, T4-T12 thoracic kyphosis, and L1-S1 lumbar lordosis. Da Vinci views were also generated and analyzed for each patient in the study. A panel of four experienced spine surgeons from the SRS 3D Scoliosis Committee reviewed and evaluated each group to determine if cluster groups were clinically distinct from each other.

Results: The clustering algorithm was able to detect 11 sub-groups. The population size for each cluster varied from 11 to 290. Statistically significant differences were seen between the parameters for each group. Four spine surgeons reviewed the three most representative cases of each group and unanimously agreed that each cluster group represents a sub-group that was not defined in current classifications.

Conclusions: This study presents a new method of classifying AIS based on a fuzzy clustering algorithm using parameters describing the 3D characteristics of the deformity. Further clinical validation is needed to confirm the usefulness of this classification system.

Level Of Evidence: IV.
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http://dx.doi.org/10.1007/s43390-020-00051-2DOI Listing
June 2020

The use of classification and regression tree analysis to identify the optimal surgical timing for improving neurological outcomes following motor-complete thoracolumbar traumatic spinal cord injury.

Spinal Cord 2020 Jun 28;58(6):682-688. Epub 2020 Jan 28.

Department of Surgery, Hôpital du Sacré-Coeur de Montréal, 5400 Boulevard Gouin O, Montreal, QC, H4J 1C5, Canada.

Study Design: Observational cohort study.

Objectives: To identify the optimal surgical timing for improving neurological outcomes in patients that sustained a motor-complete traumatic spinal cord injury (TSCI) secondary to a thoracolumbar injury.

Setting: Level 1 trauma center specialized in TSCI care.

Methods: We prospectively analyzed clinical data of 35 patients admitted for motor-complete TSCI secondary to a thoracolumbar injury. We quantified neurological recovery with three different outcomes: the improvement of at least one grade on the American Spinal Injury Association Impairment Scale (AIS), of at least one neurological level of injury (NLI), and of at least 10-points on the motor score (MS). Classification and regression tree analysis was used to identify outcome predictors and to provide cutoff values of surgical timing associated with recovery.

Results: The proportion of the patients improving by at least one AIS grade was higher in the group undergoing early surgery within 25.7 h of the TSCI (46% vs 0%). The proportion of patients that improved by at least one NLI was also higher in the group undergoing early surgery within 21.5 h of the TSCI (71% vs 18%). Lastly, 25% of the AIS grade A patients undergoing early surgery within 25.6 h of the TSCI improved 10 MS points or more as compared with 0% in the other group.

Conclusions: Earlier surgery was effective in improving neurological outcome in motor-complete TSCI at the thoracolumbar levels. Performing surgery within 21.5 h from the traumatic event in these patients increases the likelihood of improving the neurological recovery.

Sponsorship: This study was supported by the Fonds de Recherche du Québec-Santé (FRQS), Department of the Army-United States Army Medical Research Acquisition Activity, Rick Hansen Spinal Cord Injury Registry and Medtronic research chair in spinal trauma at Université de Montréal.
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http://dx.doi.org/10.1038/s41393-020-0412-zDOI Listing
June 2020

Dynamics of spinal cord compression with different patterns of thoracolumbar burst fractures: Numerical simulations using finite element modelling.

Clin Biomech (Bristol, Avon) 2020 02 24;72:186-194. Epub 2019 Dec 24.

Department of Mechanical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; International Laboratory on Spine Imaging and Biomechanics (iLab-Spine), Canada. Electronic address:

Background: In thoracolumbar burst fractures, spinal cord primary injury involves a direct impact and energy transfer from bone fragments to the spinal cord. Unfortunately, imaging studies performed after the injury only depict the residual bone fragments position and pattern of spinal cord compression, with little insight on the dynamics involved during traumas. Knowledge of underlying mechanisms could be helpful in determining the severity of the primary injury, hence the extent of spinal cord damage and associated potential for recovery. Finite element models are often used to study dynamic processes, but have never been used specifically to simulate different severities of thoracolumbar burst fractures.

Methods: Previously developed thoracolumbar spine and spinal cord finite element models were used and further validated, and representative vertebral fragments were modelled. A full factorial design was used to investigate the effects of comminution of the superior fragment, presence of an inferior fragment, fragments rotation and velocity, on maximum Von Mises stress and strain, maximum major strain, and pressure in the spinal cord.

Findings: Fragment velocity clearly was the most influential factor. Fragments rotation and presence of an inferior fragment increased pressure, but rotation decreased both strains outputs. Although significant for both strains outputs, comminution of the superior fragment isn't estimated to influence outputs.

Interpretation: This study is the first, to the authors' knowledge, to examine a detailed spinal cord model impacted in situ by fragments from burst fractures. This numeric model could be used in the future to comprehensively link traumatic events or imaging study characteristics to known spinal cord injuries severity and potential for recovery.
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http://dx.doi.org/10.1016/j.clinbiomech.2019.12.023DOI Listing
February 2020

Defining criteria for optimal lumbar curve correction following the selective thoracic fusion surgery in Lenke 1 adolescent idiopathic scoliosis: developing a decision tree.

Eur J Orthop Surg Traumatol 2020 Apr 23;30(3):513-522. Epub 2019 Nov 23.

Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada.

Objective: The aim of this study was to identify the range of optimal versus suboptimal rates of spontaneous lumbar Cobb correction (SLCC%) and the factors predicting such outcomes in a cohort of Lenke 1 adolescent idiopathic scoliosis (AIS) after posterior spinal fusion surgery.

Methods: Seventy-one consecutive Lenke1 B and C AIS patients with a fusion level to L1 and higher with two-year follow-up were included. Thoracic kyphosis (T1-T4 and T4-T12 TK), lumbar lordosis (L1-S1 LL), thoracic and lumbar Cobb angles, thoracic and lumbar apical vertebral rotations and translations (AVR and AVT), pelvic incidence, sacral slope, and sagittal and frontal balances were measured at preoperative, early postoperative, and two-year follow-up. The SLCC% was calculated between preoperative and two-year follow-up. A clustering analysis determined the subgroups of patients with significantly higher and lower (optimal versus suboptimal) rate of SLCC% in the cohort at two-year follow-up. The cutoff values of the preoperative and early postoperative radiographic parameters that significantly predicted the optimal and suboptimal SLCC% were determined using a decision tree.

Results: The averages of the optimal versus suboptimal range of SLCC% in the cohort were 72% [55%, 105%] versus 39% [- 7%, 42%]. Preoperative and early postoperative spinal parameters predicted the optimal versus suboptimal SLCC% with an accuracy of 82%, 95%CI [0.73-0.94]. Preoperative AVT < 10 mm was a predictor of optimal SLCC%. In patients with a preoperative AVT > 10 mm, early postoperative T4-T12 TK < 24° (but not less than 17°) accompanied by - 5° < AVR < 5° were the main predictors of optimal SLCC% in our cohort.

Conclusion: Quantitative clustering of the SLCC% into optimal and suboptimal groups allowed identifying the cutoff values of preoperative (AVT) and early postoperative (T4-T12 TK and AVR) spinal parameters that can predict the optimal range of SLCC% at two-year postoperative in our cohort of Lenke 1 AIS.

Level Of Evidence: IV.
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http://dx.doi.org/10.1007/s00590-019-02596-zDOI Listing
April 2020

A Predictive Model of Progression for Adolescent Idiopathic Scoliosis Based on 3D Spine Parameters at First Visit.

Spine (Phila Pa 1976) 2020 May;45(9):605-611

CHU Sainte-Justine, Montréal, Québec, Canada.

MINI: The aim of this prospective cohort study was to improve the prediction of curve progression in AIS. By adding the 3D morphology parameters at first visit, the predictive model explains 65% of the variability. It is one of the greatest advances in the understanding of scoliosis progression in the last 30 years.

Study Design: Prospective cohort study.

Objective: The objective of the present study was to design a model of AIS progression to predict Cobb angle at full skeletal maturity, based on curve type, skeletal maturation, and 3D spine parameters available at first visit.

Summary Of Background Data: Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity that affects 1% of adolescents. Curve severity is assessed using the Cobb angle. Prediction of scoliosis progression remains challenging for the treating physician and is currently based on curve type, severity, and maturity. The objective of this study was to develop a predictive model of final Cobb angle, based on 3D spine parameters at first visit, to optimize treatment.

Methods: A prospective cohort of AIS patients at first orthopedic visit was enrolled between 2006 and 2010, all with 3D reconstructions. Measurements of five types of descriptors were obtained: angle of plane of maximum curvature, Cobb angles, 3D wedging, rotation, and torsion. A general linear model analysis with backward selection was done with final Cobb angle (either just before surgery or at skeletal maturity) as outcome and 3D spine parameters and clinical parameters as predictors.

Results: Of 195 participants, 172 (88%) were analyzed; average age at presentation was 12.5 ± 1.3 years and mean follow-up to outcome, 3.2 years. The final model includes significant predictors: initial skeletal maturation, curve type, frontal Cobb angle, angle of plane of maximal curvature, and 3D disk wedging (T3-T4, T8-T9) and achieved a determination coefficient (R) = 0.643. Positive and negative predictive values to identify a curve of 35 degrees are 79% and 94%.

Conclusion: This study developed a predictive model of spinal curve progression in scoliosis based on first-visit information. The model will help the treating physician to initiate appropriate treatment at first visit.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003316DOI Listing
May 2020

Patterns and predictors of functional recovery from the subacute to the chronic phase following a traumatic spinal cord injury: a prospective study.

Spinal Cord 2020 Jan 28;58(1):43-52. Epub 2019 Aug 28.

Faculty of Medicine, Department of medicine, University of Montreal, Pavillon Roger-Gaudry, S-749, C.P. 6128, succ. Centre-ville, Montreal, QC, H3C 3J7, Canada.

Study Design: Prospective cohort study.

Objectives: To determine the extent of functional recovery between 6 and 12 months following a traumatic spinal cord injury (TSCI) and to identify individuals achieving a small clinical functional improvement during this period.

Setting: A single level-1 trauma center specialized in SCI care.

Methods: A cohort of 125 patients sustaining TSCI was studied. The Spinal Cord Independence Measure (SCIM) version III at 6 and 12 months post injury was used as the main outcome measure.

Results: The observed functional improvement for the final cohort did not reach a clinically significant level between 6 and 12 months post injury. However, 30.4% of individuals achieved this level (≥4 points in the SCIM-III total score). This group showed a higher proportion of motor-complete TSCI (AIS grade A or B) and showed a tendency toward older age and higher trauma severity. Longer duration of intensive functional rehabilitation was the single factor associated with reaching a small clinically important improvement in the SCIM-III total score.

Conclusions: Functional status between 6 and 12 months following a TSCI may be considered clinically similar, regardless of the level of injury. However, 30% may reach a small clinical functional improvement in the subacute to chronic phase following TSCI, particularly individuals sustaining severe deficits and older age, which may highlight the importance of functional compensation during this period for these patients.
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http://dx.doi.org/10.1038/s41393-019-0341-xDOI Listing
January 2020

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

Neurology 2019 09 13;93(12):e1205-e1211. Epub 2019 Aug 13.

From the International Collaboration on Repair Discoveries (J.W.S., C.R.W., B.K.K.); MD/PhD Training Program (J.W.S.), School of Kinesiology (C.R.W.), and Department of Orthopaedics (R.C.-M., J.S., T.A., S. Paquette, N.D., C.G.F., M.F.D.), University of British Columbia; Vancouver Spine Program (L.M.B., A.T., L.R.), Vancouver General Hospital, British Columbia; Department of Surgery (J.-M.M.-T., S. Parent), Hôpital du Sacré-Coeur de Montréal, and Chu Sainte-Justine (S.C.), Department of Surgery, Université de Montréal, Quebec; Division of Orthopaedic Surgery (C.B.), London Health Sciences Centre, University of Western Ontario, Canada; Department of Neurological Surgery (S.D.), University of California, San Francisco; Vancouver Spine Surgery Institute (R.C.-M., J.S., T.A., S. Paquette, N.D., C.G.F., M.F.D., B.K.K.); and Division of Neurosurgery (B.K.K.), University of British Columbia, Blusson Spinal Cord Centre, Vancouver, Canada.

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.
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http://dx.doi.org/10.1212/WNL.0000000000008125DOI Listing
September 2019

Traumatic Spinal Cord Injuries with Fractures in a Québec Level I Trauma Center.

Can J Neurol Sci 2019 11;46(6):727-734

Department of Mechanical Engineering, École de technologie supérieure, Montreal, Quebec, Canada.

Background: Traumatic spinal cord injuries (TSCI) have devastating consequences on patients' quality of life. More specifically, TSCI with spinal fractures (TSCIF) have the most severe neurological impairment, although limited data are available. This study aimed at providing data and analyzing TSCIF in a level I trauma center in the province of Québec, Canada.

Methods: Two hundred eighty-two TSCIF were reviewed. Spinal injuries and neurological impairment were assessed with AO classification and AIS, respectively. Variables included age, sex, cause, location, mechanism of injury (MOI), and severity of TSCIF. Chi-squared Pearson determined significant associations (p < 0.05).

Results: Male-to-female ratio was 3.21:1. Patients were 42.5 ± 18.7 years. The leading causes of TSCIF were high-energy falls (28.4%), cars (26.2%) and vehicle without restraint system (motorcycle, all-terrain vehicle, snowmobile, and bicycle) (21.3%). Vehicle collisions, pooling cars and unrestrained vehicles, mostly affected the 20-49-year population (62.2%). The main MOI was distraction in males (47.9%), and axial compression in females (44.8%). There were significant associations between causes and injured spinal level, as well as between MOI and injured spinal level, sex, and TSCIF severity. Most patients involved in unrestrained vehicle accidents sustained a thoracolumbar spine distraction with complete motor deficit. A severe neurologic deficit affected most patients following car accidents that caused cervical spine distraction or axial torsion.

Conclusions: In Québec, most TSCIF caused by vehicle collisions affect a young population and have severe neurological impairments. Future efforts should focus on better understanding accidents involving the unrestrained vehicle category to further improve preventive measures.
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http://dx.doi.org/10.1017/cjn.2019.252DOI Listing
November 2019
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