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"Martin, Allan R."
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Traumatic and nontraumatic spinal cord injury: pathological insights from neuroimaging
by
Cohen-Adad, Julien
,
Gergely, David
,
Martin, Allan R
in
Medical imaging
,
Pathology
,
Spinal cord injuries
2019
Pathophysiological changes in the spinal cord white and grey matter resulting from injury can be observed with MRI techniques. These techniques provide sensitive markers of macrostructural and microstructural tissue integrity, which correlate with histological findings. Spinal cord MRI findings in traumatic spinal cord injury (tSCI) and nontraumatic spinal cord injury — the most common form of which is degenerative cervical myelopathy (DCM) — have provided important insights into the pathophysiological processes taking place not just at the focal injury site but also rostral and caudal to the spinal injury. Although tSCI and DCM have different aetiologies, they show similar degrees of spinal cord pathology remote from the injury site, suggesting the involvement of similar secondary degenerative mechanisms. Advanced quantitative MRI protocols that are sensitive to spinal cord pathology have the potential to improve diagnosis and, more importantly, predict outcomes in patients with tSCI or nontraumatic spinal cord injury. This Review describes the insights into tSCI and DCM that have been revealed by neuroimaging and outlines current activities and future directions for the field.
Journal Article
Symptomatic spinal metastasis: A systematic literature review of the preoperative prognostic factors for survival, neurological, functional and quality of life in surgically treated patients and methodological recommendations for prognostic studies
by
Choi, David
,
Nater, Anick
,
Martin, Allan R.
in
Analysis
,
Back surgery
,
Biology and Life Sciences
2017
While several clinical prediction rules (CPRs) of survival exist for patients with symptomatic spinal metastasis (SSM), these have variable prognostic ability and there is no recognized CPR for health related quality of life (HRQoL). We undertook a critical appraisal of the literature to identify key preoperative prognostic factors of clinical outcomes in patients with SSM who were treated surgically. The results of this study could be used to modify existing or develop new CPRs.
Seven electronic databases were searched (1990-2015), without language restriction, to identify studies that performed multivariate analysis of preoperative predictors of survival, neurological, functional and HRQoL outcomes in surgical patients with SSM. Individual studies were assessed for class of evidence. The strength of the overall body of evidence was evaluated using GRADE for each predictor.
Among 4,818 unique citations, 17 were included; all were in English, rated Class III and focused on survival, revealing a total of 46 predictors. The strength of the overall body of evidence was very low for 39 and low for 7 predictors. Due to considerable heterogeneity in patient samples and prognostic factors investigated as well as several methodological issues, our results had a moderately high risk of bias and were difficult to interpret.
The quality of evidence for predictors of survival was, at best, low. We failed to identify studies that evaluated preoperative prognostic factors for neurological, functional, or HRQoL outcomes in surgical patients with SSM. We formulated methodological recommendations for prognostic studies to promote acquiring high-quality evidence to better estimate predictor effect sizes to improve patient education, surgical decision-making and development of CPRs.
Journal Article
Monitoring for myelopathic progression with multiparametric quantitative MRI
by
Crawley, Adrian
,
Tetreault, Lindsay
,
Kalsi-Ryan, Sukhvinder
in
Anisotropy
,
Assessments
,
Atrophy
2018
Patients with mild degenerative cervical myelopathy (DCM) are often managed non-operatively, and surgery is recommended if neurological progression occurs. However, detection of progression is often subjective. Quantitative MRI (qMRI) directly measures spinal cord (SC) tissue changes, detecting axonal injury, demyelination, and atrophy. This longitudinal study compared multiparametric qMRI with clinical measures of progression in non-operative DCM patients.
26 DCM patients were followed. Clinical data included modified Japanese Orthopedic Association (mJOA) and additional assessments. 3T qMRI data included cross sectional area, diffusion fractional anisotropy, magnetization transfer ratio, and T2*-weighted white/grey matter signal ratio, extracted from the compressed SC and above/below. Progression was defined as 1) patients' subjective impression, 2) 2-point mJOA decrease, 3) ≥3 clinical measures worsening ≥5%, 4) increased compression on MRI, or 5) ≥1 of 10 qMRI measures or composite score worsening (p < 0.004, corrected).
Follow-up (13.5 ± 4.9 months) included mJOA in all 26 patients, MRI in 25, and clinical/qMRI in 22. 42.3% reported subjective worsening, compared with mJOA (11.5%), MRI (20%), comprehensive assessments (54.6%), and qMRI (68.2%). Relative to subjective worsening, qMRI showed 100% sensitivity and 53.3% specificity compared with comprehensive assessments (75%, 60%), mJOA (27.3%, 100%), and MRI (18.2%, 81.3%). A decision-making algorithm incorporating qMRI identified progression and recommended surgery for 11 subjects (42.3%).
Quantitative MRI shows high sensitivity to detect myelopathic progression. Our results suggest that neuroplasticity and behavioural adaptation may mask progressive SC tissue injury. qMRI appears to be a useful method to confirm subtle myelopathic progression in individual patients, representing an advance toward clinical translation of qMRI.
Journal Article
Recent advances in managing a spinal cord injury secondary to trauma
by
Ahuja, Christopher S.
,
Fehlings, Michael G
,
Martin, Allan R.
in
Developmental & Pediatric Neurology
,
Motor Systems
,
Neurobiology of Disease & Regeneration
2016
Traumatic spinal cord injuries (SCIs) affect 1.3 million North Americans, producing devastating physical, social, and vocational impairment. Pathophysiologically, the initial mechanical trauma is followed by a significant secondary injury which includes local ischemia, pro-apoptotic signaling, release of cytotoxic factors, and inflammatory cell infiltration. Expedient delivery of medical and surgical care during this critical period can improve long-term functional outcomes, engendering the concept of “Time is Spine”. We emphasize the importance of expeditious care while outlining the initial clinical and radiographic assessment of patients. Key evidence-based early interventions (surgical decompression, blood pressure augmentation, and methylprednisolone) are also reviewed, including findings of the landmark Surgical Timing in Acute Spinal Cord Injury Study (STASCIS). We then describe other neuroprotective approaches on the edge of translation such as the sodium-channel blocker riluzole, the anti-inflammatory minocycline, and therapeutic hypothermia. We also review promising neuroregenerative therapies that are likely to influence management practices over the next decade including chondroitinase, Rho-ROCK pathway inhibition, and bioengineered strategies. The importance of emerging neural stem cell therapies to remyelinate denuded axons and regenerate neural circuits is also discussed. Finally, we outline future directions for research and patient care.
Journal Article
Degenerative Cervical Myelopathy: Development and Natural History AO Spine RECODE-DCM Research Priority Number 2
by
Schaller, Karl
,
Molliqaj, Granit
,
Cheng, Joseph S.
in
Clinical deterioration
,
Natural history
,
Special Issue
2022
Study Design:
Narrative review.
Objectives:
To discuss the current understanding of the natural history of degenerative cervical myelopathy (DCM).
Methods:
Literature review summarizing current evidence pertaining to the natural history and risk factors of DCM.
Results:
DCM is a common condition in which progressive arthritic disease of the cervical spine leads to spinal cord compression resulting in a constellation of neurological symptoms, in particular upper extremity dysfunction and gait impairment. Anatomical factors including cord-canal mismatch, congenitally fused vertebrae and genetic factors may increase individuals’ risk for DCM development. Non-myelopathic spinal cord compression (NMSCC) is a common phenomenon with a prevalence of 24.2% in the healthy population, and 35.3% among individuals >60 years of age. Clinical radiculopathy and/or electrophysiological signs of cervical cord dysfunction appear to be risk factors for myelopathy development. Radiological progression of incidental Ossification of the Posterior Longitudinal Ligament (OPLL) is estimated at 18.3% over 81-months and development of myelopathy ranges between 0-61.5% (follow-up ranging from 40 to 124 months between studies) among studies. In patients with symptomatic DCM undergoing non-operative treatment, 20-62% will experience neurological deterioration within 3-6 years.
Conclusion:
Current estimates surrounding the natural history of DCM, particularly those individuals with mild or minimal impairment, lack precision. Clear predictors of clinical deterioration for those treated with non-operative care are yet to be identified. Future studies are needed on this topic to help improve treatment counseling and clinical prognostication.
Journal Article
Assessing the diagnostic accuracy of symptoms and signs of degenerative cervical myelopathy: A prospective study
by
Roberto, Rolando F.
,
Ortuno, Omar
,
Tetreault, Lindsay
in
692/617/375/1824
,
692/617/375/364
,
Adult
2025
Degenerative cervical myelopathy (DCM) is a clinical diagnosis based on history, physical exam, and imaging, but standardized criteria have not been established, contributing to diagnostic delays. We conducted a prospective study of DCM and healthy subjects that comprehensively evaluated symptoms, patient-reported and clinician-administered outcome measures, and physical assessments of motor and sensory function.Diagnostic utility was evaluated using Youden’s Index (YI=sensitivity+specificity-1). 139 DCM patients and 108 age-matched healthy subjects were compared. Distinguishing symptoms included neck pain (YI=63%), upper extremity (UE) numbness (YI=57%), hand clumsiness (YI=50%), walking imbalance (YI=50%), and UE weakness (YI=46%). Questionnaires performed well including mJOA (YI=72%), NDI (YI=63%), and EQ-5D (YI=57%). Physical testing showed best results with UE reflexes (YI=54%), strength in 5 UE muscle groups (YI=53%), Berg Balance scale (YI=50%), self-paced walking velocity (YI=48%), and tandem gait assessment (YI=40%). Hand dexterity, strength dynamometry, and testing of 5 sensory modalities demonstrated poor diagnostic utility. Diagnosis of DCM is challenging, but key symptoms include neck pain, UE weakness, and those captured by the mJOA (particularly UE numbness, hand clumsiness, and walking imbalance). Physical testing of reflexes, manual motor testing, and gait/balance are useful to confirm the diagnosis. These findings offer guidance for clinicians and the development of diagnostic criteria.
Journal Article
Imaging and Electrophysiology for Degenerative Cervical Myelopathy AO Spine RECODE-DCM Research Priority Number 9
by
Rahimi-Movaghar, Vafa
,
Tetreault, Lindsay
,
Harrop, James S.
in
Magnetic resonance imaging
,
Special Issue
,
Spinal cord
2022
Study Design
Narrative review.
Objective
The current review aimed to describe the role of existing techniques and emerging methods of imaging and electrophysiology for the management of degenerative cervical myelopathy (DCM), a common and often progressive condition that causes spinal cord dysfunction and significant morbidity globally.
Methods
A narrative review was conducted to summarize the existing literature and highlight future directions.
Results
Anatomical magnetic resonance imaging (MRI) is well established in the literature as the key imaging tool to identify spinal cord compression, disc herniation/bulging, and inbuckling of the ligamentum flavum, thus facilitating surgical planning, while radiographs and computed tomography (CT) provide complimentary information. Electrophysiology techniques are primarily used to rule out competing diagnoses. However, signal change and measures of cord compression on conventional MRI have limited utility to characterize the degree of tissue injury, which may be helpful for diagnosis, prognostication, and repeated assessments to identify deterioration. Early translational studies of quantitative imaging and electrophysiology techniques show potential of these methods to more accurately reflect changes in spinal cord microstructure and function.
Conclusion
Currently, clinical management of DCM relies heavily on anatomical MRI, with additional contributions from radiographs, CT, and electrophysiology. Novel quantitative assessments of microstructure, perfusion, and function have the potential to transform clinical practice, but require robust validation, automation, and standardization prior to uptake.
Journal Article
Degenerative Cervical Myelopathy: A Practical Approach to Diagnosis
2022
Study Design
Narrative Review.
Objectives
The objective of this review is to provide a stepwise approach to the assessment of patients with potential symptoms of degenerative cervical myelopathy (DCM).
Methods
N/A
Results
DCM is an overarching term used to describe progressive compression of the cervical spinal cord by age-related changes to the spinal axis. These alterations to normal anatomy narrow the spinal canal, reduce the space available for the spinal cord, and may ultimately compress the ascending and descending neural tracts. Patients with DCM present with a wide range of symptoms that can significantly impact quality of life, including bilateral hand numbness and paresthesia, gait impairment, motor weakness of the upper and lower extremities, and bladder and bowel dysfunction. Unfortunately, DCM is often misdiagnosed, resulting in delayed assessment and management by the appropriate specialist. The proper evaluation of a patient with suspected DCM includes obtaining a detailed patient history, conducting a comprehensive neurological examination, and ordering appropriate tests to rule in or out other diagnoses.
Conclusion
This review summarizes a stepwise approach to the diagnosis of patients with DCM.
Journal Article
Augmented Reality Navigation for Extreme Lateral Interbody Fusion with Posterior Instrumentation: Feasibility, Outcomes, and Surgical Technique
by
Cranick, Matileen G.
,
Castillo, Jose A.
,
Price, Richard L.
in
Accuracy
,
Augmented Reality
,
Bone surgery
2025
Background: Extreme lateral interbody fusion (XLIF) is a minimally invasive spine procedure that traditionally relies on fluoroscopy and neuromonitoring for safe disc space access and instrumentation. Augmented reality (AR) navigation offers real-time anatomical visualization and may reduce fluoroscopy use. This is the first description of applying augmented reality to lateral spine surgery. Methods: We conducted a case series of five patients who underwent AR-guided LLIF between May 2024 and July 2025. Surgery was performed in either lateral decubitus or prone transpsoas (PTP) orientation. AR navigation was performed using the Augmedics xvision Spine System, with intraoperative CT–based registration and optical tool tracking. Clinical and operative data, including operative time, estimated blood loss (EBL), length of stay (LOS), radiation exposure, instrumentation accuracy, and postoperative outcomes, were collected and analyzed. Results: Five patients (4 female, 1 male; age > 65; BMI range 20.7–37.2) underwent AR-guided XLIF across 8 levels (L2–L5). The mean operative time was 5 h 1 min (range: 2 h 8 min–6 h 45 min), and mean EBL was 94 mL. Mean LOS was 5.85 days (range: 2–10). Mean radiation exposure was 21.73 mGy, significantly lower than published averages for fluoroscopy-guided XLIF (108.6 mGy). At follow-up, all patients reported pain reduction, with 4/5 achieving complete symptom resolution. Instrumentation accuracy was confirmed radiographically in all cases. Conclusions: This clinical series demonstrates the first clinical application of AR to lateral lumbar interbody fusion. AR navigation was feasible, safe, and effective, providing accurate disc space access and instrumentation with markedly reduced radiation exposure. These findings support AR as a promising adjunct to improve safety, efficiency, and workflow in lateral spine surgery.
Journal Article
The Role of Magnetic Resonance Imaging to Inform Clinical Decision-Making in Acute Spinal Cord Injury: A Systematic Review and Meta-Analysis
by
Mayank Kaushal
,
Stefan F Lange
,
Lindsay Tetreault
in
4.2 Evaluation of markers and technologies
,
Bias
,
Biomedical Imaging
2021
The clinical indications and added value of obtaining MRI in the acute phase of spinal cord injury (SCI) remain controversial. This review aims to critically evaluate evidence regarding the role of MRI to influence decision-making and outcomes in acute SCI. A systematic review and meta-analysis were performed according to PRISMA methodology to identify studies that address six key questions (KQs) regarding diagnostic accuracy, frequency of abnormal findings, frequency of altered decision-making, optimal timing, and differences in outcomes related to obtaining an MRI in acute SCI. A total of 32 studies were identified that addressed one or more KQs. MRI showed no adverse events in 156 patients (five studies) and frequently identified cord compression (70%, 12 studies), disc herniation (43%, 16 studies), ligamentous injury (39%, 13 studies), and epidural hematoma (10%, two studies), with good diagnostic accuracy (seven comparative studies) except for fracture detection. MRI findings often altered management, including timing of surgery (78%, three studies), decision to operate (36%, 15 studies), and surgical approach (29%, nine studies). MRI may also be useful to determine the need for instrumentation (100%, one study), which levels to decompress (100%, one study), and if reoperation is needed (34%, two studies). The available literature consistently concluded that MRI was useful prior to surgical treatment (13 studies) and after surgery to assess decompression (two studies), but utility before/after closed reduction of cervical dislocations was unclear (three studies). One study showed improved outcomes with an MRI-based protocol but had a high risk of bias. Heterogeneity was high for most findings (I2 > 0.75). MRI is safe and frequently identifies findings alter clinical management in acute SCI, although direct evidence of its impact on outcomes is lacking. MRI should be performed before and after surgery, when feasible, to facilitate improved clinical decision-making. However, further research is needed to determine its optimal timing, effect on outcomes, cost-effectiveness, and utility before and after closed reduction.
Journal Article