Anick Nater | University of Toronto (original) (raw)
Papers by Anick Nater
The Spine Journal, Sep 1, 2019
The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases.... more The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases. The data were cleaned and then analyzed using recursive feature elimination analysis, stability selection analysis, and principal component analysis to determine the correlations between the DSIC scheme parameters and the DSIC scheme grade, between the DSIC scheme parameters and the surgical treatment, and between selected parameters and the surgical treatment of DLS. Machine learning models (support vector machine and logistic regression) built using Python-based libraries were used to test the strength of the correlations found. RESULTS: For the DSIC scheme classification and associated treatment, most cases of DLS were classified as being Type II (potentially unstable) (52%). However, most cases (61%) were treated with a 360˚fusion regardless of their stability. In fact, only 18% of cases were classified as being Type III and thus demanding the TLIF/PLIF procedure. For Type I cases, the surgical treatment corresponding to Type I was employed 41% of the time. The use of appropriate surgical treatment was much lower for Type II (17%). For Type III, 91% of cases were treated with the recommended procedure. Dynamic translation was the parameter found to be the most correlated with the DSIC grade, with an r value of 0.475. Meyerding Grade and Disc Angle Standing were the two parameters most correlated with treatment decision-making, with respective first principal components of 0.374 and 0.332. CONCLUSIONS: This study presented the demographics of DLS classification and treatment, which demonstrated that most surgeons are choosing the most extensive surgical procedure, 360˚fusion, even when not indicated by the DSIC scheme. The study also found important correlations between patient and surgeon parameters and DLS classification and treatment, eg, dynamic translation influencing the classification and Meyerding Grade influencing the treatment. A larger data set would likely provide even better correlation results. Further efforts are needed to develop a new scoring algorithm that would serve to classify the stability of DLS based on the correlations found in this study. This new scoring algorithm would be extremely clinically significant as it would be more comprehensible and reproducible than the DSIC scheme and able to guide the treatment of DLS. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Advances in Experimental Medicine and Biology, 2023
The Spine Journal, Oct 1, 2016
Global Spine Journal, May 1, 2019
Study Design: Review. Objectives: The objectives of this review are to (a) summarize the role of ... more Study Design: Review. Objectives: The objectives of this review are to (a) summarize the role of clinical practice guidelines (CPGs), (b) outline the methodology involved in formulating CPGs, (c) provide an illustration of these principles using a CPG developed for degenerative cervical myelopathy, and (d) highlight the importance of knowledge translation. Methods: A review of the literature was conducted to summarize current standards in CPG development and implementation. Results: CPGs are systematically developed statements intended to affect decisions made by health care providers, policy makers, and patients. The main objectives of CPGs are to synthesize and translate evidence into recommendations, optimize patient outcomes, standardize care, and facilitate shared decision making among physicians, patients, and their caregivers. The main steps involved in the development of CPGs include defining the clinical problem, assembling a multidisciplinary guideline development group and systematic review team, conducting a systematic review of the literature, translating the evidence to recommendations, critically appraising the CPG and updating the document when new studies arise. The final step in developing a CPG is to implement it into clinical practice; this step requires an assessment of the barriers to implementation and the formulation of effective dissemination strategies. Conclusion: CPGs are an important component in the teaching and practice of medicine and are available for a wide spectrum of diseases. CPGs, however, can only be used to influence clinical practice if the recommendations are informed by a systematic review of the literature and developed using rigorous methodology. The opportunity to transform clinical management of spinal conditions is an attractive outcome of the application of high-quality CPGs.
Neurosurgery Clinics of North America, Apr 1, 2015
Although it is intuitive that any neurosurgeon would seek to consistently apply the best availabl... more Although it is intuitive that any neurosurgeon would seek to consistently apply the best available evidence to patient management, the application of evidence-based medicine (EBM) principles and clinical practice guidelines (CPGs) remains variable. This article reviews the origin and process of EBM, and the development, assessment, and applicability of EBM and CPGs in neurosurgical care, aiming to demonstrate that CPGs are one of the valid available options that exist to improve quality of care. CPGs are not intended to define the standard of care but to compile dynamic advisory statements, which need to be updated as new evidence emerges.
World Neurosurgery, Sep 1, 2017
We conducted a survey to understand how specific pathologic features on magnetic resonance imagin... more We conducted a survey to understand how specific pathologic features on magnetic resonance imaging (MRI) influence surgeons toward an anterior or posterior surgical approach in degenerative cervical myelopathy (DCM). A questionnaire was sent out to 6179 AOSpine International members via e-mail. This included 18 questions on a 7-point Likert scale regarding how MRI features influence the respondent's decision to perform an anterior or posterior surgical approach. Influence was classified based on the mean and mode. Variations in responses were assessed by region and training. Of 513 respondents, 51.7% were orthopedic surgeons, 36.8% were neurosurgeons, and the remainder were fellows, residents, or other. In ascending order, multilevel bulging disks, cervical kyphosis, and a high degree of anterior cord compression had a moderate to strong influence toward an anterior approach. A high degree of posterior cord compression had a moderate to strong influence, whereas multilevel compression, ossification of the posterior longitudinal ligament, ligamentum flavum enlargement, and congenital stenosis had a moderate influence toward a posterior approach. Neurosurgeons chose anterior approaches more and posterior approaches less in comparison with orthopedic surgeons (P < 0.01). Of note, 59.8% of respondents were equally comfortable performing multilevel (3 or more levels) anterior and posterior procedures, whereas 61.5% did not feel comfortable in determining the surgical approach based on MRI alone. Specific DCM pathology influences the choice for anterior or posterior surgical approach. These data highlight factors based on surgeon experience, training, and region of practice. They will be helpful in defining future areas of investigation in an effort to provide individualized surgical strategies and optimize patient outcomes.
The Spine Journal, Oct 1, 2016
Global Spine Journal, May 1, 2015
The Spine Journal, Oct 1, 2016
Investigating the relationship between Modic changes and chronic lower back pain in patients rece... more Investigating the relationship between Modic changes and chronic lower back pain in patients receiving surgical therapy for lumbar disc herniation: a retrospective chart review
Aizheng, Mar 16, 2016
Background: High quality studies have been challenging to undertake in patients with metastatic e... more Background: High quality studies have been challenging to undertake in patients with metastatic epidural spinal cord compression. Nonetheless, in the article "Survival and Clinical Outcomes in Surgically Treated Patients With Metastatic Epidural Spinal Cord Compression: Results of the Prospective Multicenter AOSpine Study" recently published in the Journal of Clinical Oncology, our team provided convincing evidence that spinal surgery improves overall quality of life in patients with this potentially devastating complication of cancer. Considering that metastatic spinal lesions treated with surgery have the highest mean cost among all oncological musculo-skeletal issues, it is essential to provide high quality data to optimize the therapeutic approaches and cost-effective use of health care resources. Main body: Although the AOSpine Study provided high quality prospective data, it was primarily limited by the lack of non-operative controls and the relatively small sample size. Given the dearth of medical equipoise and the fundamental difference between patients deemed to be adequate surgical candidates and those who are not amenable to operative intervention, conducting a randomized controlled trial in this patient population was not felt to be ethically or medically feasible. Consequently, the optimal option to overcome limitations of both the lack of controls and the relatively small sample size is through collection of large prospective datasets through rigorously developed and maintained registries. Conclusions: With the alarming increase in the incidence of cancer in China and China's parallel growing cancer control efforts, China would offer a fantastic platform to set up a national metastatic spinal lesion registry. Such registry would not only enhance metastatic epidural spinal cord compression translational research but also optimize patient care.
Benzel's Spine Surgery, 2-Volume Set, 2017
This chapter reviews the imaging armamentarium, including conventional radiograph, computerized t... more This chapter reviews the imaging armamentarium, including conventional radiograph, computerized tomography, magnetic resonance, nuclear medicine, and molecular imaging, and the evidence supporting their usage for the diagnosis, evaluation, and staging of primary and metastatic spinal tumors and the assessment of the overall tumor burden. In addition, special imaging considerations after surgical or radiotherapy treatment, as well as upcoming imaging technologies, in the evaluation and staging of adult spine tumors are discussed.
The Spine Journal, 2019
The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases.... more The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases. The data were cleaned and then analyzed using recursive feature elimination analysis, stability selection analysis, and principal component analysis to determine the correlations between the DSIC scheme parameters and the DSIC scheme grade, between the DSIC scheme parameters and the surgical treatment, and between selected parameters and the surgical treatment of DLS. Machine learning models (support vector machine and logistic regression) built using Python-based libraries were used to test the strength of the correlations found. RESULTS: For the DSIC scheme classification and associated treatment, most cases of DLS were classified as being Type II (potentially unstable) (52%). However, most cases (61%) were treated with a 360˚fusion regardless of their stability. In fact, only 18% of cases were classified as being Type III and thus demanding the TLIF/PLIF procedure. For Type I cases, the surgical treatment corresponding to Type I was employed 41% of the time. The use of appropriate surgical treatment was much lower for Type II (17%). For Type III, 91% of cases were treated with the recommended procedure. Dynamic translation was the parameter found to be the most correlated with the DSIC grade, with an r value of 0.475. Meyerding Grade and Disc Angle Standing were the two parameters most correlated with treatment decision-making, with respective first principal components of 0.374 and 0.332. CONCLUSIONS: This study presented the demographics of DLS classification and treatment, which demonstrated that most surgeons are choosing the most extensive surgical procedure, 360˚fusion, even when not indicated by the DSIC scheme. The study also found important correlations between patient and surgeon parameters and DLS classification and treatment, eg, dynamic translation influencing the classification and Meyerding Grade influencing the treatment. A larger data set would likely provide even better correlation results. Further efforts are needed to develop a new scoring algorithm that would serve to classify the stability of DLS based on the correlations found in this study. This new scoring algorithm would be extremely clinically significant as it would be more comprehensible and reproducible than the DSIC scheme and able to guide the treatment of DLS. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Neurosurgery, 2019
INTRODUCTION Surgery is generally considered for patients with metastatic epidural spinal cord co... more INTRODUCTION Surgery is generally considered for patients with metastatic epidural spinal cord compression (MESCC) with life expectancy >3 mo. No existing clinical prognostic models (CPMs) of survival are consistently used, and no CPMs exist which predict quality of life (QoL) following surgical treatment. These knowledge gaps are important given the challenges involved in managing MESCC. METHODS Using TRIPOD guidelines and data from 258 patients (AOSpine North America (NA) MESCC study and Nottingham MESCC registry), we created 1-yr survival and QoL CPMs using Cox model and logistic regression with manual backward elimination. The outcome measure for QoL was the minimal clinical important difference (MCID) in EQ5D scores. Internal validation involved 200 bootstrap iterations; calibration and discrimination were evaluated. RESULTS Higher SF-36 physical component score (PCS) (HR: 0.96) was associated with longer survival whereas primary tumor other than breast, thyroid, and prostat...
The Spine Journal, 2017
(1) Hirabayashi recovery ratio, (2) a dichotomized mJOA score of <16 and ≥16 at 2-years represent... more (1) Hirabayashi recovery ratio, (2) a dichotomized mJOA score of <16 and ≥16 at 2-years representing a suboptimal and optimal neurological outcome, respectively. RESULTS: MRIs were categorized by T1WI and T2WI signal change: no signal change (28.9%), T2WI hyperintensity-only (T2WI-only, 51.8%), and T2WI-hyperintensity and T1WI-hypointensity (T1WI+T2WI, 19.3%). T2WIhyperintensity was present at multiple levels in 27% of patients overall. There was moderate to substantial agreement (Fleiss Kappa: 0.60) for T2WI hyperintensity, and fair agreement for T1WI hypointensity (Fleiss Kappa: 0.31) among 3 raters for 317 subjects. Baseline severity increased from no signal change to T2WI-only to T2WI+T1WI (p<.0001), and there was an incremental increase in the frequency of signs/symptoms. There were no differences in outcomes between no signal change and T2WI-only groups. The presence of T1WI-hypointensity correlated with reduced recovery ratio (p=.03) and likelihood of an optimal surgical outcome (p=.005), adjusting for baseline mJOA. A greater number of T2WI-hyperintensity levels was also associated with worse baseline severity (p<.0001) and recovery ratio (p=.001). CONCLUSIONS: This analysis of a global cohort of DCM patients shows a stepwise trend toward increasing impairment from no signal change to T2WI hypertensity to T1WI hypointensity. T1WI signal change indicates more permanent injury, portending decreased functional recovery. T2WI hyperintensity alone does not predict outcomes. Multiple levels of T2WI hyperintensity suggest additional tissue injury, correlating with worse clinical impairment and recovery potential.
Spine, 2017
To report the global prevalence of specific degenerative cervical pathologies in patients with DC... more To report the global prevalence of specific degenerative cervical pathologies in patients with DCM through detailed review of MRIs Summary of Background Data: Degenerative Cervical Myelopathy (DCM) encompasses a spectrum of age-related conditions that result in progressive spinal cord injury. Methods: MRIs of 458 patients (age 56.4 +/-11.8, 285 Male, 173 Female) patients were reviewed for specific degenerative features, directionality of cord compression, levels of spinal cord compression, and signal changes on T2WI and T1WI.Data were analyzed for differences between sex using Chi-square tests and geographic variations using Kruskal-Wallis tests. Results: Spondylosis was frequently present (89.7%) and was commonly accompanied by enlargement of the ligamentum flavum (LF) (59.9%). Single level disc pathology, Ossification of posterior longitudinal ligament (OPLL) and spondylolisthesis had a prevalence of ~10% each. OPLL was accompanied by spondylosis in 91.7%. Klippel-Feil Syndrome was observed in 2.0%. The Asia-Pacificregion had more OPLL (29%, p=3x10-11) and less spondylolisthesis (1.9%, p=0.002). Females presented more commonly with single level disc pathology (13.9% vs. 6.7%; p=0.013), and males with spondylosis (92.3% vs. 85.6%; p=0.02) and enlargement of LF (61.4% vs. 49.1%; p=0.01). C5-6 was the most frequent maximum compressed site (39.5%) and region for T2WI hyperintensity (38.9%). T2WI hyperintensity more commonly presented in males (82.4% vs. 66.7%; p<0.001). Conclusion: This isthe largest report on the prevalence and spectrum of pathology in patients with DCM. Herein it has been demonstrated thatdegenerative features are highly interrelated,that females presented with milder MRI evidence of DCM, and that variations exist in the prevalence of pathologies between geographical regions.
World Neurosurgery, 2017
We conducted a survey to understand how specific pathologic features on magnetic resonance imagin... more We conducted a survey to understand how specific pathologic features on magnetic resonance imaging (MRI) influence surgeons toward an anterior or posterior surgical approach in degenerative cervical myelopathy (DCM). A questionnaire was sent out to 6179 AOSpine International members via e-mail. This included 18 questions on a 7-point Likert scale regarding how MRI features influence the respondent's decision to perform an anterior or posterior surgical approach. Influence was classified based on the mean and mode. Variations in responses were assessed by region and training. Of 513 respondents, 51.7% were orthopedic surgeons, 36.8% were neurosurgeons, and the remainder were fellows, residents, or other. In ascending order, multilevel bulging disks, cervical kyphosis, and a high degree of anterior cord compression had a moderate to strong influence toward an anterior approach. A high degree of posterior cord compression had a moderate to strong influence, whereas multilevel compression, ossification of the posterior longitudinal ligament, ligamentum flavum enlargement, and congenital stenosis had a moderate influence toward a posterior approach. Neurosurgeons chose anterior approaches more and posterior approaches less in comparison with orthopedic surgeons (P < 0.01). Of note, 59.8% of respondents were equally comfortable performing multilevel (3 or more levels) anterior and posterior procedures, whereas 61.5% did not feel comfortable in determining the surgical approach based on MRI alone. Specific DCM pathology influences the choice for anterior or posterior surgical approach. These data highlight factors based on surgeon experience, training, and region of practice. They will be helpful in defining future areas of investigation in an effort to provide individualized surgical strategies and optimize patient outcomes.
Global Spine Journal, 2015
New Approaches to the Management of Primary and Secondary CNS Tumors, 2017
Over the past two decades, increased global incidence of malignancy, improved systemic disease tr... more Over the past two decades, increased global incidence of malignancy, improved systemic disease treatment with prolonged survival, and increased central nervous system (CNS) surveillance in cancer patients have all contributed to a rise in cerebral metastatic disease. As many patients retain good neurologic function, the approach to their management has shifted markedly; a pre-terminal prognosis and palliative treatment have been replaced by individualized care plans to prolong functional survival. However, the rapid shifts in disease characteristics, treatment options and emerging evidence can be challenging to navigate, and a rational approach to brain metastases is needed. We discuss the changing epidemiology of brain metastases and consider approaches to prognostic classification. We review current treatment modalities and discuss the significant studies pertaining to each, with emphasis on Level 1 evidence when available and cooperative group trials, as well as studies on adverse effects. To integrate the information presented, we offer case scenarios that highlight pertinent decision-making factors. The shift in care goal for cerebral metastases from symptom palliation to prolongation of survival is not only feasible, but in many cases indicated. The appropriate application of various treatment modalities must be considered in the context of individual patients and their primary cancer.
The Spine Journal, Sep 1, 2019
The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases.... more The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases. The data were cleaned and then analyzed using recursive feature elimination analysis, stability selection analysis, and principal component analysis to determine the correlations between the DSIC scheme parameters and the DSIC scheme grade, between the DSIC scheme parameters and the surgical treatment, and between selected parameters and the surgical treatment of DLS. Machine learning models (support vector machine and logistic regression) built using Python-based libraries were used to test the strength of the correlations found. RESULTS: For the DSIC scheme classification and associated treatment, most cases of DLS were classified as being Type II (potentially unstable) (52%). However, most cases (61%) were treated with a 360˚fusion regardless of their stability. In fact, only 18% of cases were classified as being Type III and thus demanding the TLIF/PLIF procedure. For Type I cases, the surgical treatment corresponding to Type I was employed 41% of the time. The use of appropriate surgical treatment was much lower for Type II (17%). For Type III, 91% of cases were treated with the recommended procedure. Dynamic translation was the parameter found to be the most correlated with the DSIC grade, with an r value of 0.475. Meyerding Grade and Disc Angle Standing were the two parameters most correlated with treatment decision-making, with respective first principal components of 0.374 and 0.332. CONCLUSIONS: This study presented the demographics of DLS classification and treatment, which demonstrated that most surgeons are choosing the most extensive surgical procedure, 360˚fusion, even when not indicated by the DSIC scheme. The study also found important correlations between patient and surgeon parameters and DLS classification and treatment, eg, dynamic translation influencing the classification and Meyerding Grade influencing the treatment. A larger data set would likely provide even better correlation results. Further efforts are needed to develop a new scoring algorithm that would serve to classify the stability of DLS based on the correlations found in this study. This new scoring algorithm would be extremely clinically significant as it would be more comprehensible and reproducible than the DSIC scheme and able to guide the treatment of DLS. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Advances in Experimental Medicine and Biology, 2023
The Spine Journal, Oct 1, 2016
Global Spine Journal, May 1, 2019
Study Design: Review. Objectives: The objectives of this review are to (a) summarize the role of ... more Study Design: Review. Objectives: The objectives of this review are to (a) summarize the role of clinical practice guidelines (CPGs), (b) outline the methodology involved in formulating CPGs, (c) provide an illustration of these principles using a CPG developed for degenerative cervical myelopathy, and (d) highlight the importance of knowledge translation. Methods: A review of the literature was conducted to summarize current standards in CPG development and implementation. Results: CPGs are systematically developed statements intended to affect decisions made by health care providers, policy makers, and patients. The main objectives of CPGs are to synthesize and translate evidence into recommendations, optimize patient outcomes, standardize care, and facilitate shared decision making among physicians, patients, and their caregivers. The main steps involved in the development of CPGs include defining the clinical problem, assembling a multidisciplinary guideline development group and systematic review team, conducting a systematic review of the literature, translating the evidence to recommendations, critically appraising the CPG and updating the document when new studies arise. The final step in developing a CPG is to implement it into clinical practice; this step requires an assessment of the barriers to implementation and the formulation of effective dissemination strategies. Conclusion: CPGs are an important component in the teaching and practice of medicine and are available for a wide spectrum of diseases. CPGs, however, can only be used to influence clinical practice if the recommendations are informed by a systematic review of the literature and developed using rigorous methodology. The opportunity to transform clinical management of spinal conditions is an attractive outcome of the application of high-quality CPGs.
Neurosurgery Clinics of North America, Apr 1, 2015
Although it is intuitive that any neurosurgeon would seek to consistently apply the best availabl... more Although it is intuitive that any neurosurgeon would seek to consistently apply the best available evidence to patient management, the application of evidence-based medicine (EBM) principles and clinical practice guidelines (CPGs) remains variable. This article reviews the origin and process of EBM, and the development, assessment, and applicability of EBM and CPGs in neurosurgical care, aiming to demonstrate that CPGs are one of the valid available options that exist to improve quality of care. CPGs are not intended to define the standard of care but to compile dynamic advisory statements, which need to be updated as new evidence emerges.
World Neurosurgery, Sep 1, 2017
We conducted a survey to understand how specific pathologic features on magnetic resonance imagin... more We conducted a survey to understand how specific pathologic features on magnetic resonance imaging (MRI) influence surgeons toward an anterior or posterior surgical approach in degenerative cervical myelopathy (DCM). A questionnaire was sent out to 6179 AOSpine International members via e-mail. This included 18 questions on a 7-point Likert scale regarding how MRI features influence the respondent's decision to perform an anterior or posterior surgical approach. Influence was classified based on the mean and mode. Variations in responses were assessed by region and training. Of 513 respondents, 51.7% were orthopedic surgeons, 36.8% were neurosurgeons, and the remainder were fellows, residents, or other. In ascending order, multilevel bulging disks, cervical kyphosis, and a high degree of anterior cord compression had a moderate to strong influence toward an anterior approach. A high degree of posterior cord compression had a moderate to strong influence, whereas multilevel compression, ossification of the posterior longitudinal ligament, ligamentum flavum enlargement, and congenital stenosis had a moderate influence toward a posterior approach. Neurosurgeons chose anterior approaches more and posterior approaches less in comparison with orthopedic surgeons (P < 0.01). Of note, 59.8% of respondents were equally comfortable performing multilevel (3 or more levels) anterior and posterior procedures, whereas 61.5% did not feel comfortable in determining the surgical approach based on MRI alone. Specific DCM pathology influences the choice for anterior or posterior surgical approach. These data highlight factors based on surgeon experience, training, and region of practice. They will be helpful in defining future areas of investigation in an effort to provide individualized surgical strategies and optimize patient outcomes.
The Spine Journal, Oct 1, 2016
Global Spine Journal, May 1, 2015
The Spine Journal, Oct 1, 2016
Investigating the relationship between Modic changes and chronic lower back pain in patients rece... more Investigating the relationship between Modic changes and chronic lower back pain in patients receiving surgical therapy for lumbar disc herniation: a retrospective chart review
Aizheng, Mar 16, 2016
Background: High quality studies have been challenging to undertake in patients with metastatic e... more Background: High quality studies have been challenging to undertake in patients with metastatic epidural spinal cord compression. Nonetheless, in the article "Survival and Clinical Outcomes in Surgically Treated Patients With Metastatic Epidural Spinal Cord Compression: Results of the Prospective Multicenter AOSpine Study" recently published in the Journal of Clinical Oncology, our team provided convincing evidence that spinal surgery improves overall quality of life in patients with this potentially devastating complication of cancer. Considering that metastatic spinal lesions treated with surgery have the highest mean cost among all oncological musculo-skeletal issues, it is essential to provide high quality data to optimize the therapeutic approaches and cost-effective use of health care resources. Main body: Although the AOSpine Study provided high quality prospective data, it was primarily limited by the lack of non-operative controls and the relatively small sample size. Given the dearth of medical equipoise and the fundamental difference between patients deemed to be adequate surgical candidates and those who are not amenable to operative intervention, conducting a randomized controlled trial in this patient population was not felt to be ethically or medically feasible. Consequently, the optimal option to overcome limitations of both the lack of controls and the relatively small sample size is through collection of large prospective datasets through rigorously developed and maintained registries. Conclusions: With the alarming increase in the incidence of cancer in China and China's parallel growing cancer control efforts, China would offer a fantastic platform to set up a national metastatic spinal lesion registry. Such registry would not only enhance metastatic epidural spinal cord compression translational research but also optimize patient care.
Benzel's Spine Surgery, 2-Volume Set, 2017
This chapter reviews the imaging armamentarium, including conventional radiograph, computerized t... more This chapter reviews the imaging armamentarium, including conventional radiograph, computerized tomography, magnetic resonance, nuclear medicine, and molecular imaging, and the evidence supporting their usage for the diagnosis, evaluation, and staging of primary and metastatic spinal tumors and the assessment of the overall tumor burden. In addition, special imaging considerations after surgical or radiotherapy treatment, as well as upcoming imaging technologies, in the evaluation and staging of adult spine tumors are discussed.
The Spine Journal, 2019
The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases.... more The patient data was collected by CSORN between 2015 and 2018 and included 224 DLS surgery cases. The data were cleaned and then analyzed using recursive feature elimination analysis, stability selection analysis, and principal component analysis to determine the correlations between the DSIC scheme parameters and the DSIC scheme grade, between the DSIC scheme parameters and the surgical treatment, and between selected parameters and the surgical treatment of DLS. Machine learning models (support vector machine and logistic regression) built using Python-based libraries were used to test the strength of the correlations found. RESULTS: For the DSIC scheme classification and associated treatment, most cases of DLS were classified as being Type II (potentially unstable) (52%). However, most cases (61%) were treated with a 360˚fusion regardless of their stability. In fact, only 18% of cases were classified as being Type III and thus demanding the TLIF/PLIF procedure. For Type I cases, the surgical treatment corresponding to Type I was employed 41% of the time. The use of appropriate surgical treatment was much lower for Type II (17%). For Type III, 91% of cases were treated with the recommended procedure. Dynamic translation was the parameter found to be the most correlated with the DSIC grade, with an r value of 0.475. Meyerding Grade and Disc Angle Standing were the two parameters most correlated with treatment decision-making, with respective first principal components of 0.374 and 0.332. CONCLUSIONS: This study presented the demographics of DLS classification and treatment, which demonstrated that most surgeons are choosing the most extensive surgical procedure, 360˚fusion, even when not indicated by the DSIC scheme. The study also found important correlations between patient and surgeon parameters and DLS classification and treatment, eg, dynamic translation influencing the classification and Meyerding Grade influencing the treatment. A larger data set would likely provide even better correlation results. Further efforts are needed to develop a new scoring algorithm that would serve to classify the stability of DLS based on the correlations found in this study. This new scoring algorithm would be extremely clinically significant as it would be more comprehensible and reproducible than the DSIC scheme and able to guide the treatment of DLS. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Neurosurgery, 2019
INTRODUCTION Surgery is generally considered for patients with metastatic epidural spinal cord co... more INTRODUCTION Surgery is generally considered for patients with metastatic epidural spinal cord compression (MESCC) with life expectancy >3 mo. No existing clinical prognostic models (CPMs) of survival are consistently used, and no CPMs exist which predict quality of life (QoL) following surgical treatment. These knowledge gaps are important given the challenges involved in managing MESCC. METHODS Using TRIPOD guidelines and data from 258 patients (AOSpine North America (NA) MESCC study and Nottingham MESCC registry), we created 1-yr survival and QoL CPMs using Cox model and logistic regression with manual backward elimination. The outcome measure for QoL was the minimal clinical important difference (MCID) in EQ5D scores. Internal validation involved 200 bootstrap iterations; calibration and discrimination were evaluated. RESULTS Higher SF-36 physical component score (PCS) (HR: 0.96) was associated with longer survival whereas primary tumor other than breast, thyroid, and prostat...
The Spine Journal, 2017
(1) Hirabayashi recovery ratio, (2) a dichotomized mJOA score of <16 and ≥16 at 2-years represent... more (1) Hirabayashi recovery ratio, (2) a dichotomized mJOA score of <16 and ≥16 at 2-years representing a suboptimal and optimal neurological outcome, respectively. RESULTS: MRIs were categorized by T1WI and T2WI signal change: no signal change (28.9%), T2WI hyperintensity-only (T2WI-only, 51.8%), and T2WI-hyperintensity and T1WI-hypointensity (T1WI+T2WI, 19.3%). T2WIhyperintensity was present at multiple levels in 27% of patients overall. There was moderate to substantial agreement (Fleiss Kappa: 0.60) for T2WI hyperintensity, and fair agreement for T1WI hypointensity (Fleiss Kappa: 0.31) among 3 raters for 317 subjects. Baseline severity increased from no signal change to T2WI-only to T2WI+T1WI (p<.0001), and there was an incremental increase in the frequency of signs/symptoms. There were no differences in outcomes between no signal change and T2WI-only groups. The presence of T1WI-hypointensity correlated with reduced recovery ratio (p=.03) and likelihood of an optimal surgical outcome (p=.005), adjusting for baseline mJOA. A greater number of T2WI-hyperintensity levels was also associated with worse baseline severity (p<.0001) and recovery ratio (p=.001). CONCLUSIONS: This analysis of a global cohort of DCM patients shows a stepwise trend toward increasing impairment from no signal change to T2WI hypertensity to T1WI hypointensity. T1WI signal change indicates more permanent injury, portending decreased functional recovery. T2WI hyperintensity alone does not predict outcomes. Multiple levels of T2WI hyperintensity suggest additional tissue injury, correlating with worse clinical impairment and recovery potential.
Spine, 2017
To report the global prevalence of specific degenerative cervical pathologies in patients with DC... more To report the global prevalence of specific degenerative cervical pathologies in patients with DCM through detailed review of MRIs Summary of Background Data: Degenerative Cervical Myelopathy (DCM) encompasses a spectrum of age-related conditions that result in progressive spinal cord injury. Methods: MRIs of 458 patients (age 56.4 +/-11.8, 285 Male, 173 Female) patients were reviewed for specific degenerative features, directionality of cord compression, levels of spinal cord compression, and signal changes on T2WI and T1WI.Data were analyzed for differences between sex using Chi-square tests and geographic variations using Kruskal-Wallis tests. Results: Spondylosis was frequently present (89.7%) and was commonly accompanied by enlargement of the ligamentum flavum (LF) (59.9%). Single level disc pathology, Ossification of posterior longitudinal ligament (OPLL) and spondylolisthesis had a prevalence of ~10% each. OPLL was accompanied by spondylosis in 91.7%. Klippel-Feil Syndrome was observed in 2.0%. The Asia-Pacificregion had more OPLL (29%, p=3x10-11) and less spondylolisthesis (1.9%, p=0.002). Females presented more commonly with single level disc pathology (13.9% vs. 6.7%; p=0.013), and males with spondylosis (92.3% vs. 85.6%; p=0.02) and enlargement of LF (61.4% vs. 49.1%; p=0.01). C5-6 was the most frequent maximum compressed site (39.5%) and region for T2WI hyperintensity (38.9%). T2WI hyperintensity more commonly presented in males (82.4% vs. 66.7%; p<0.001). Conclusion: This isthe largest report on the prevalence and spectrum of pathology in patients with DCM. Herein it has been demonstrated thatdegenerative features are highly interrelated,that females presented with milder MRI evidence of DCM, and that variations exist in the prevalence of pathologies between geographical regions.
World Neurosurgery, 2017
We conducted a survey to understand how specific pathologic features on magnetic resonance imagin... more We conducted a survey to understand how specific pathologic features on magnetic resonance imaging (MRI) influence surgeons toward an anterior or posterior surgical approach in degenerative cervical myelopathy (DCM). A questionnaire was sent out to 6179 AOSpine International members via e-mail. This included 18 questions on a 7-point Likert scale regarding how MRI features influence the respondent's decision to perform an anterior or posterior surgical approach. Influence was classified based on the mean and mode. Variations in responses were assessed by region and training. Of 513 respondents, 51.7% were orthopedic surgeons, 36.8% were neurosurgeons, and the remainder were fellows, residents, or other. In ascending order, multilevel bulging disks, cervical kyphosis, and a high degree of anterior cord compression had a moderate to strong influence toward an anterior approach. A high degree of posterior cord compression had a moderate to strong influence, whereas multilevel compression, ossification of the posterior longitudinal ligament, ligamentum flavum enlargement, and congenital stenosis had a moderate influence toward a posterior approach. Neurosurgeons chose anterior approaches more and posterior approaches less in comparison with orthopedic surgeons (P < 0.01). Of note, 59.8% of respondents were equally comfortable performing multilevel (3 or more levels) anterior and posterior procedures, whereas 61.5% did not feel comfortable in determining the surgical approach based on MRI alone. Specific DCM pathology influences the choice for anterior or posterior surgical approach. These data highlight factors based on surgeon experience, training, and region of practice. They will be helpful in defining future areas of investigation in an effort to provide individualized surgical strategies and optimize patient outcomes.
Global Spine Journal, 2015
New Approaches to the Management of Primary and Secondary CNS Tumors, 2017
Over the past two decades, increased global incidence of malignancy, improved systemic disease tr... more Over the past two decades, increased global incidence of malignancy, improved systemic disease treatment with prolonged survival, and increased central nervous system (CNS) surveillance in cancer patients have all contributed to a rise in cerebral metastatic disease. As many patients retain good neurologic function, the approach to their management has shifted markedly; a pre-terminal prognosis and palliative treatment have been replaced by individualized care plans to prolong functional survival. However, the rapid shifts in disease characteristics, treatment options and emerging evidence can be challenging to navigate, and a rational approach to brain metastases is needed. We discuss the changing epidemiology of brain metastases and consider approaches to prognostic classification. We review current treatment modalities and discuss the significant studies pertaining to each, with emphasis on Level 1 evidence when available and cooperative group trials, as well as studies on adverse effects. To integrate the information presented, we offer case scenarios that highlight pertinent decision-making factors. The shift in care goal for cerebral metastases from symptom palliation to prolongation of survival is not only feasible, but in many cases indicated. The appropriate application of various treatment modalities must be considered in the context of individual patients and their primary cancer.