Cause Of Spinal Cord Dysfunction Research Articles

Socioeconomic and regional differences in the treatment of cervical spondylotic myelopathy.

Background:Cervical spondylotic myelopathy (CSM) is the leading cause of spinal cord dysfunction in the world. Surgical treatment is both medically and economically advantageous, and can be achieved through multiple approaches, with or without fusion. We used the Nationwide Inpatient Sample (NIS) database to better elucidate regional and socioeconomic variances in the treatment of CSM.Methods:The NIS database was queried for elective admissions with a primary diagnosis of CSM (ICD-9 721.1). This was evaluated for patients who also carried a diagnosis of anterior (ICD-9 81.02) or posterior cervical fusion (ICD-9 81.03), posterior cervical laminectomy (ICD 03.09), or a combination. We then investigated variances including regional trends and disparities according to hospital and insurance types.Results:During 2002–2012, 50605 patients were electively admitted with a diagnosis of CSM. Anterior fusions were more common in Midwestern states and in nonteaching hospitals. Fusion procedures were used more frequently than other treatments in private hospitals and with private insurance. Median hospital charges were also expectedly higher for fusion procedures and combined surgical approaches. Combined approaches were found to be significantly greater in patients with concurrent diagnoses of ossification of the posterior longitudinal ligament (OPLL) and CSM. Ultimately, there has been an increased utilization of fusion procedures versus nonfusion treatments, over the past decade, for patients with cervical myelopathy.Conclusions:Fusion surgery is being increasingly used for the treatment of CSM. Expensive procedures are being performed more frequently in both private hospitals and for those with private insurance, whereas the most economical procedure, posterior cervical laminectomy, was underutilized.

Hyperbaric oxygen therapy and comprehensive orthopedic treatment for incomplete traumatic spinal cord injury on the qinghai-tibet plateau: Study protocol for an open-label randomized controlled clinical trial

Background: Apoptosis secondary to ischemia and hypoxia is the main cause of spinal cord dysfunction. Because of the decrease in atmospheric pressure, patients living on the Qinghai-Tibet Plateau are in a hypoxic environment, which is very unfavorable for the recovery of spinal cord injury. Hyperbaric oxygen therapy can improve the postoperative function of patients with incomplete spinal cord injury, and its effect is better on the plateau than at normal altitudes. We performed a prospective randomized controlled clinical trial to observe the effect of hyperbaric oxygen therapy on traumatic spinal cord injury in patients living on the Qinghai-Tibet Plateau and are currently analyzing the results. Methods/Design: This prospective, open-label, randomized controlled clinical trial was performed at the Department of Spine Surgery, Affiliated Hospital of Qinghai University, China. In total, 164 patients with incomplete traumatic spinal cord injury were equally and randomly assigned to a control group and a hyperbaric oxygen therapy group. Patients in the control group were treated with pedicle screw fixation and decompressive laminectomy. In addition to the surgical treatment performed in the control group, patients in the hyperbaric oxygen group underwent hyperbaric oxygen therapy at 0.2 MPa once a day for four treatment courses. Ten treatment sessions constituted one course, and each course was separated by a 5- to 7-day rest interval. The primary outcome was the modified Barthel index to assess activities of daily living. The secondary outcomes were the American Spinal Injury Association (ASIA) impairment scale grade, sensory score, and motor score. The partial results demonstrated that after four treatment courses (55–61 days), the modified Barthel index and ASIA tactile, pain, and motor scores were higher in the hyperbaric oxygen group than in the control group. The ASIA grades were significantly different between the hyperbaric oxygen group and control group. The proportion of patients with ASIA grades D and E was higher in the hyperbaric oxygen group than in the control group. Discussion: The study design was finished in May 2012. Patient recruitment began in June 2012 and finished until February 2016.Data analysis will be finished in December 2017. In this trial, we aim to determine the efficacy of hyperbaric oxygen therapy on the treatment of incomplete traumatic spinal cord injury in patients living on the plateau and to provide clinical evidence for treating incomplete traumatic spinal cord injury in these patients. Trial registration: ClinicalTrials.gov identifier: NCT03112941. Ethics: The study protocol has been approved by Ethics Committee, Affiliated Hospital of Qinghai University, China in April 2012 (approval number: QHC011K). Informed consent: Written informed consent was obtained from relatives or legal representatives.

Proportion recovery and times to ambulation for non-ambulatory dogs with thoracolumbar disc extrusions treated with hemilaminectomy or conservative treatment: A systematic review and meta-analysis of case-series studies

Thoracolumbar intervertebral disc extrusion is a common cause of spinal cord dysfunction in dogs. Peer-reviewed studies reporting treatment of predominantly chondrodystrophic dogs with disc extrusion with loss of ambulation with either hemilaminectomy or conservative treatment (rest, analgesics and anti-inflammatories) were evaluated in a systematic review of the literature.Generally, the level of evidence available was low with no controlled studies and only case series available. In the meta-analysis, there was a clear trend to a greater proportion of dogs recovering and returning faster to ambulation for dogs treated with hemilaminectomy than for conservatively treated dogs. The mean proportions that recovered for neurological grades 3, 4 and 5 were 93, 93 and 61% for those treated with hemilaminectomy, and 79, 62 and 10% for those treated conservatively (Grade 3 – non-ambulatory paraparetic dogs; grade 4 – paraplegic dogs with intact deep pain perception; grade 5 – paraplegic dogs without intact deep pain perception). Due to the use of case series, these results represent between-study comparisons, thereby increasing the risk of selection bias and other biases. Data presented in this review support the current recommendations for surgical management of non-ambulatory dogs with disc-extrusion, but controlled clinical studies comparing outcomes are necessary to confirm these findings.

Management of degenerative cervical myelopathy - An update.

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction in adult patients. Patients generally present with a slow, progressive neurological decline or a stepwise deterioration pattern. In this paper, we discuss the most important factors involved in the management of DCM, including a discussion about the surgical approaches. The authors performed an extensive review of the peer-reviewed literature addressing the aforementioned objectives. Although the diagnosis is clinical, magnetic resonance imaging (MRI) is the study of choice to confirm stenosis and also to exclude the differential diagnosis. The severity the clinical symptoms of DCM are evaluated by different scales, but the modified Japanese Orthopedic Association (mJOA) and the Nürick scale are probably the most commonly used. Spontaneous clinical improvement is rare and surgery is the main treatment form in an attempt to prevent further neurological deterioration and, potentially, to provide some improvement in symptoms and function. Anterior, posterior or combined cervical approaches are used to decompress the spinal cord, with adjunctive fusion being commonly performed. The choice of one approach over the other depends on patient characteristics (such as number of involved levels, site of compression, cervical alignment, previous surgeries, bone quality, presence of instability, among others) as well as surgeon preference and experience. Spine surgeons must understand the advantages and disadvantages of all surgical techniques to choose the best procedure for their patients. Further comparative studies are necessary to establish the superiority of one approach over the other when multiple options are available.

Myelopathic signs and functional outcome following cervical decompression surgery: a proposed myelopathy scale.

OBJECTIVE Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction in adults. In spite of this, the impact of the changes in myelopathic signs following cervical decompression surgery and their relationship to functional outcome measures remains unclear. The main goals of our study were to prospectively assess changes in myelopathic signs with a functional outcome scale (the modified Japanese Orthopaedic Association [mJOA] scale) following cervical decompression surgery and to objectively test a proposed new myelopathy scale (MS). METHODS Between 2008 and 2011, 36 patients with CSM were observed following cervical decompression surgery. Patient data including mJOA and MS scores were prospectively collected and analyzed preoperatively and at 1 year after surgery. RESULTS In this cohort, reflex, Babinski, and proprioception signs showed statistically significant improvement following surgery at 1 year (p = < 0.001, p = 0.008, and p = 0.015, respectively). A lesser degree of improvement was observed with the Hoffman sign (p = 0.091). No statistically significant improvement in clonus occurred (p = 0.368). There was a significant improvement in mJOA (p ≤ 0.001) and MS (p ≤ 0.001) scores at 1 year compared with the preoperative scores. The results showed an inverse correlation between MS and mJOA scores both pre- and postoperatively (Spearman's correlation coefficient = -0.202 preoperatively and -0.361 postoperatively). CONCLUSIONS Improvement in myelopathic signs was noted following cervical decompression surgery in patients with CSM. The newly devised MS scale demonstrated these findings, and the new MS scale correlates with improvement in mJOA scores in this patient cohort.

Surgical Decompression for Degenerative Cervical Myelopathy

Degenerative cervical myelopathy remains the most common cause of spinal cord dysfunction in adults worldwide and is one of the most common causes of

Hybrid Decompression and Fixation Technique for the Treatment of Multisegmental Cervical Spondylotic Myelopathy.

Cervical spondilotic myelopathy (CSM) is defined as the compromise of the spinal cord due to degenerative changes of the cervical spine. It is the most common cause of spinal cord dysfunction in patients over 55 years. An early surgical management it is paramount to achieve better neurological outcome. There is still controversy regarding the appropriate surgical treatment for multisegmental CSM involving three or more levels. The hybrid decompression and fixation technique combines one or two level corpectomy and a single level discectomy in order to obtain optimum decompression and fixation in patients with multilevel cervical myelopathy. A prospective case-control study was made between 2011 and 2013. A total of 15 patients with diagnosis of CSM received surgical treatment with an anterior hybrid decompression and fixation technique procedure. Inclusion criteria were myelopathy confirmed by radiographic studies, magnetic resonance image (MRI) and electromyography. During the 2010-2013 period 15 patients were managed by hybrid decompression and fixation technique. Average age 64.8 years SD9.4. The follow up period was 29.6 SD ± 9.8 months. The JOA score improved significantly to 13.8 +/- 1.9 points at follow-up (paired t test, P = 0.001), Nurick Scale preoperative was 3.3 and improved to 2.4 mean, was significantly (Wilcoxon signed rank test p=0.006) The mean C2-C7 lordosis angle was 10.8° +/- 8.9 before surgery, and 14.3° +/- 8.8 at follow-up, there was no significant loss of lordosis angle between the preoperative and follow-up measurements (Wilcoxon signed rank test, P =0.149); At follow-up, graft non fusion was seen in 1 patient (7%, k=1). In this small number, single surgeon, prospective series the use of a single level corpectomy and an adjacent discectomy was shown to provide similar outcomes and complication rates as alternative surgical techniques. The authors thus consider this a viable surgical alternative with some perceived advantages, a low rate of complications and a high rate of spinal fusion. Level of Evidence: IV. This study was approved by the authors' Institutional Review Board and all patients were given informed consent prior to participation in the study.

Sensitivity of Pyramidal Signs in Patients with Cervical Spondylotic Myelopathy.

Study DesignThis was a retrospective study.PurposeThe purpose of this study was to study the relationship between prevalence of pyramidal signs and the severity of cervical myelopathy. The study is focused on patients having increased signal intensity in T2-weighted magnetic resonance imaging.Overview of LiteratureCervical spondylotic myelopathy is the most common cause of spinal cord dysfunction in elderly population. It is the consequence of spondylotic changes leading to cervical cord injury with resulting clinical deficits. Diagnosis in such patients is made based on clinical and radiographic features. A patient must have both symptoms and signs consistent with cervical cord injury as well as radiographic evidence of damage to spondylotic cord.MethodsForty-six patients with complaint of cervical spondylotic myelopathy with increased signal intensity in T2-weighted magnetic resonance imaging were included in the study. The neurological finding of the patients was reviewed for the presence of pyramidal signs. The prevalence of each pyramidal sign was calculated and correlated to severity of cervical myelopathy. The motor function scores of the upper and lower extremities for cervical myelopathy set by the Japanese Orthopedic Association (motor Japanese Orthopaedic Association score, m-JOA) scores were used to assess severity of myelopathy.ResultsThe most prevalent signs were hyperreflexia (89.1%), Hoffmann reflex (80.4%), Babiniski sign (56.5%), and ankle clonus (39.1%). Babiniski sign, ankle clonus, and Hoffmann reflex showed significant association with the lower m-JOA score.ConclusionsIn patients with cervical myelopathy, hyperreflexia exhibited highest sensitivity whereas ankle clonus demonstrated lowest sensitivity. The prevalence of the pyramidal signs is correlated with increasing severity of myelopathy.

Surgery vs Conservative Care for Cervical Spondylotic Myelopathy: Surgery Is Appropriate for Progressive Myelopathy.

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction.1 The condition presents insidiously and is defined in terms of its clinical symptoms (gait instability, bladder dysfunction, fine finger motor difficulties) and signs (hyperreflexia, weakness, alteration of joint position sense). CSM is caused by dynamic repeated compression of the spinal cord from degenerative arthritis of the cervical spine.2 Proposed mechanisms include axonal stretch-associated injury2 and spinal cord ischemia from compression of larger vessels and impaired microcirculation.3,4 Surgery to decompress and stabilize the spine is often advocated for severe or progressive symptoms, with mixed results. About two-thirds of patients improve with surgery, while surgery does not result in improvement in 15%-30%.5 Over 112,400 cervical spine operations for degenerative spondylosis are performed annually in the US (100% increase over the past decade),6 with CSM accounting for nearly 20% of cervical spine operations in the US.7 Annual hospital charges for CSM surgery exceeds 2 billion dollars per year.6 In addition, CSM is associated with substantial postoperative outpatient expenses (e.g., physician visits, imaging, physical therapy, medications). Recently, the Institute of Medicine designated CSM as one of the top 100 national health research priorities for comparative effectiveness research.8 There is a great need for modern prospective studies with validated outcomes tools to assess the effectiveness of surgical treatments for CSM. Most American cervical spine experts (both orthopaedic and neurological surgeons) believe that there is sufficient clinical equipoise to support a comparative randomized clinical trial (RCT) if the study population is carefully defined.9 Most experts feel that surgery can prevent the progression of spinal cord dysfunction and can, in many cases, improve the symptoms of cervical spondylotic myelopathy. It is unclear, however, what the optimal surgical technique might be (ventral versus dorsal), and in up to 30% of cases the clinical outcome is not satisfactory.5 Furthermore, the complication rate for CSM surgery is high (17% in a recent prospective study),10 particularly in patients over 74 years of age,11 which is a growing segment of the US population.12 Lastly, the 5-year re-operation rate following surgery for CSM is nearly 15%.13

Does Magnetic Resonance Imaging Improve the Predictive Performance of a Validated Clinical Prediction Rule Developed to Evaluate Surgical Outcome in Patients With Degenerative Cervical Myelopathy?

Ambispective study. To determine whether MRI parameters improve the predictive performance of a validated clinical prediction rule used to assess functional outcomes in surgical patients with DCM. Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction in the elderly worldwide. A clinical prediction rule was developed to discriminate between patients with mild myelopathy postoperatively (mJOA ≥ 16) and those with substantial residual neurological impairment (mJOA < 16). Recently, a separate magnetic resonance imaging (MRI)-based prediction model was created. However, a model exploring the combined predictive value of imaging and clinical variables does not exist. One hundred and fourteen patients with MRIs were examined from a cohort of 278 patients enrolled in the AOSpine CSM-North America Study. Ninety-nine patients had complete preoperative imaging and postoperative outcome data. MRIs were evaluated for the presence/absence of signal change on T2- and T1-weighted images. Quantitative analysis of the T2 signal change was conducted and maximum canal compromise and cord compression were calculated. The added predictive performance of each MRI parameter to the clinical model was evaluated using receiver operator characteristic curves. The model developed on our subsample yielded an area under the receiver operator curve (AUC) of 0.811 (95% CI: 0.726-0.896). The addition of imaging variables did not significantly improve the predictive performance. Small improvements in prediction were obtained when sagittal extent of T2 hyperintensity (AUC: 0.826, 95% CI: 0.743-0.908, 1.35% increase) or Wang ratio (AUC: 0.823, 95% CI: 0.739-0.907, 1.21%) was added. Anatomic characteristics, such as maximum canal compromise and maximum cord compression, did not improve the discriminative ability of the clinical prediction model. In our sample of surgical patients, with clinical and image-evidence of DCM, MRI parameters do not significantly add to the predictive performance of a previously published clinical prediction rule. It remains plausible that combinations of the strongest clinical and MRI predictors may yield a similar or a superior prediction model. 3.

Myelopathy associated with microorganisms.

This article reviews the common infectious etiologies of spinal cord dysfunction that span the globe epidemiologically and vary pathophysiologically. Many microorganisms have the ability to directly or indirectly result in spinal cord dysfunction. These agents may have the ability to infect the spinal cord itself, but frequently cause indirect damage by parainfectious or postinfectious immune-mediated destruction or external compression of the spinal cord. Infectious myelopathies can pose diagnostic difficulty but are potentially reversible causes of spinal cord dysfunction. The often complex relationship among the infectious agent, the immune system, and the neuraxis can create a difficult management conundrum whereby immune modulation may be the preferred approach.

Cervical spondylotic myelopathy surgical trial: randomized, controlled trial design and rationale.

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction in the world. There are significant practice variation and uncertainty as to the optimal surgical approach for treating CSM. To determine whether ventral surgery is associated with superior Short Form-36 Physical Component Summary outcome at the 1-year follow-up compared with dorsal (laminectomy/fusion or laminoplasty) surgery for the treatment of CSM, to investigate whether postoperative sagittal balance is an independent predictor of overall outcome, and to compare health resource use for ventral and dorsal procedures. The study is a randomized, controlled trial with a nonrandomized arm for patients who are eligible but decline randomization. Two hundred fifty patients (159 randomized) with CSM from 11 sites will be recruited over 18 months. The primary outcome is the Short Form-36 Physical Component Summary score. Secondary outcomes include disease-specific outcomes, overall health-related quality of life (EuroQOL 5-dimension questionnaire), and health resource use. This will be the first randomized, controlled trial to compare directly the health-related quality-of-life outcomes for ventral vs dorsal surgery for treating CSM. A National Institutes of Health-funded (1R13AR065834-01) investigator meeting was held before the initiation of the trial to bring multiple stakeholders together to finalize the study protocol. Study investigators, coordinators, and major stakeholders were able to attend and discuss strengths of, limitations of, and concerns about the study. The final protocol was approved for funding by the Patient-Centered Outcomes Research Institute (CE-1304-6173). The trial began enrollment on April 1, 2014.

A New Experimental Animal Model of Chronic Cervical Compressive Myelopathy

Introduction Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction among adults over the age of 55?In China the morbidity of CSM is 10%. However, the pathobiology of CSM is still unclear which limits therapeutic advances for this common cause of neurological dysfunction. The clinical course of the disease remains unpredictable. The lack of reliable animal models of CSM has been a restriction to advancing the field. Up to now, various animal model of CSM have been made. Although some of these studies have impressive progress, they also have significant defects. Many of these models fail to model the chronic and progressive nature of the disease since they do not accurately reproduce the main human neuropathological and clinical features of CSM, In this study we report a new model of CSM in sheep. It is more accurate and stable than previous models. Moreover, the entire course of compression is digitized. Materials and Methods A Silicone sealed compression device is assembled with a stepping motor, gear reducer and a push rod. The compression device is connected to a circuit board which contains a bluetooth module and a control chip. Power supply is a lithium battery. Circuit board is also well sealed with silicone. It is controlled via an Android cellphone in vitro. Six male small tailed han sheep were divided into two groups randomly, four in experimental group and two in control group. The compression device was implanted into intervertebral space of C4/C5 and fixed. Circuit board was implanted subcutaneously. The control group ran no compression after surgery. Animals of each group were carried on a routine CT inspection right after the surgery. The front end of the push rod was adjusted to the posterior edge of the cervical vertebral. The experimental group pushed 0.4 mm each week while awake. Tarlov scores were assessed in each group before and after push. Results In the course of the experiment, one sheep of the experimental group appeared malfunction of the circuit board subskin. The dysfunctional board was replaced during an extra operation. The Tarlov sores of the experimental group didn't change before and after each time of push. No behavioral changes were noted in control group. While sheep in the experimental group showed gradually changes of gait. The final Tarlov score was four in three sheep and three in one sheep of the experimental group and the final radiological findings showed that the average spinal canal encroachment rate was 60.6% in the experimental group after 18 weeks’ observation. Conclusion This animal model can be used to generate controllable compression to spine operated by a digitized system. No invasive procedures were applied during the experiment. In next stage of experiment we could get specimens and run pathological tests. Disclosure of Interest None declared

Pathobiology of cervical spondylotic myelopathy

In this narrative review, we aim to outline what is currently known about the pathophysiology of cervical spondylotic myelopathy (CSM), the most common cause of spinal cord dysfunction. In particular, we note the unique factors that distinguish it from acute spinal cord injury. Despite its common occurrence, the reasons why some patients develop severe symptomatology while others have few or no symptoms despite radiographic evidence confirming similar degrees of compression is poorly understood. Neither is there a clear understanding of why certain patients have a stable clinical myelopathy and others present with only mild myelopathy. Moreover, the precise molecular mechanisms which contribute to the pathogenesis of the disease are incompletely understood. The current treatment method is decompression of the spinal cord but a lack of clinically relevant models of CSM have hindered the understanding of the full pathophysiology which would aid the development of new therapeutic avenues of investigation. Further elucidation of the role of ischemia, currently a source of debate, as well as the complex cascade of biomolecular events as a result of the unique pathophysiology in this disease will pave the way for further neuroprotective strategies to be developed to attenuate the physiological consequences of surgical decompression and augment its benefits.

Application of magnetic resonance imaging in cervical spondylotic myelopathy.

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction and is caused by static or dynamic repeated compression of the spinal cord resulting from degenerative arthritis of the cervical spine and some biological injuries to the cervical spine. The T2 signal change on conventional magnetic resonance imaging (MRI) is most commonly associated with neurological deficits. Diffusion tensor imaging and MR spectroscopy show altered microstructure and biochemistry that reflect patient-specific pathogenesis and can be used to predict neurological outcome and response to intervention. Functional MRI can help to assess the neurological functional recovery after decompression surgery for CSM.

Association of Myelopathy Scores With Cervical Sagittal Balance and Normalized Spinal Cord Volume

Post hoc analysis of prospectively collected data. Development of methods to determine in vivo spinal cord dimensions and application to correlate preoperative alignment, myelopathy, and health-related quality-of-life scores in patients with cervical spondylotic myelopathy (CSM). CSM is the leading cause of spinal cord dysfunction. The association between cervical alignment, sagittal balance, and myelopathy has not been well characterized. This was a post hoc analysis of the prospective, multicenter AOSpine North America CSM study. Inclusion criteria for this study required preoperative cervical magnetic resonance imaging (MRI) and neutral sagittal cervical radiography. Techniques for MRI assessment of spinal cord dimensions were developed. Correlations between imaging and health-related quality-of-life scores were assessed. Fifty-six patients met inclusion criteria (mean age = 55.4 yr). The modified Japanese Orthopedic Association (mJOA) scores correlated with C2-C7 sagittal vertical axis (SVA) (r = -0.282, P = 0.035). Spinal cord volume correlated with cord length (r = 0.472, P < 0.001) and cord average cross-sectional area (r = 0.957, P < 0.001). For all patients, no correlations were found between MRI measurements of spinal cord length, volume, mean cross-sectional area or surface area, and outcomes. For patients with cervical lordosis, mJOA scores correlated positively with cord volume (r = 0.366, P = 0.022), external cord area (r = 0.399, P = 0.012), and mean cross-sectional cord area (r = 0.345, P = 0.031). In contrast, for patients with cervical kyphosis, mJOA scores correlated negatively with cord volume (r = -0.496, P = 0.043) and mean cross-sectional cord area (r = -0.535, P = 0.027). This study is the first to correlate cervical sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment. It is interesting to note that sagittal balance but not kyphosis is tied to myelopathy score. Future work will correlate alignment changes to cord morphology changes and myelopathy outcomes. SUMMARY STATEMENTS: This is the first study to correlate sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment.

Pathophysiology and Natural History of Cervical Spondylotic Myelopathy

This study is a combination of narrative and systematic review. Clinicians who deal with cervical spondylotic myelopathy (CSM) should be up-to-date with the emerging knowledge related to the cascade of pathobiological secondary events that take place under chronic cervical spinal cord compression. Moreover, by performing a systematic review, we aim to (1) describe the natural history and (2) determine potential risk factors that affect the progression of CSM. The pathophysiology, natural history, as well as the factors associated with clinical deterioration have not been fully described in CSM. For the first part of the study, a literature review was performed. To answer key questions 1 and 2 of the second goal, a systematic search was conducted in PubMed and the Cochrane Collaboration Library for articles published between January 1, 1956, and November 7, 2012. We included all articles that described the progression and outcomes of CSM for which no surgical intervention was given. By performing a narrative literature review, we found that the assumption that acute traumatic spinal cord injury and CSM share a similar series of cellular and molecular secondary injury events was made in the past. However, recent advances in basic research have shown that the chronic mechanical compression results in secondary injury mechanisms that have distinct characteristics regarding the nature and the temporal profile compared with those of spinal cord injury. For the purpose of the systematic review, 10 studies yielding 16 publications met inclusion criteria for key questions 2 and 3. Moderate-strength evidence related to the natural history of CSM suggests that 20% to 60% of patients will deteriorate neurologically over time without surgical intervention. Finally, there is low-strength evidence indicating that the area of circumferential compression is associated with deteriorating neurological symptoms. CSM has unique pathobiological mechanisms that mainly remain unexplored. Although the natural history of CSM can be mixed, surgical intervention eliminates the chances of the neurological deterioration. EVIDENCE-BASED CLINICAL RECOMMENDATIONS: Evidence concerning the natural history of CSM suggests that 20% to 60% of patients will deteriorate neurologically over time without surgical intervention. Therefore, we recommend that patients with mild CSM be counseled regarding the natural history of CSM and have the option of surgical decompression explained. Moderate. Strong. SUMMARY STATEMENTS: Chronic compression of the spinal cord results in progressive neural cell loss related to secondary mechanisms including apoptosis, neuroinflammation, and vascular disruption.

Introduction: Cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction.7 The condition presents insidiously and is defined in terms of its clinical symptoms (gait instability, bladder dysfunction, fine finger motor difficulties) and signs (hyperreflexia, weakness, alteration of joint position sense). Cervical spondylotic myelopathy is caused by dynamic repeated compression of the spinal cord from degenerative arthritis of the cervical spine.2 Proposed mechanisms include axonal stretch-associated injury3 and spinal cord ischemia from compression of larger vessels and impaired microcirculation.1,2 Surgery to decompress and stabilize the spine often is advocated for severe or progressive symptoms, with mixed results. About two-thirds of patients improve with surgery, while surgery is not successful in 15%–30% of cases.5 Over 112,400 cervical spine operations for degenerative spondylosis are performed annually in the US. This represents a 100% increase over the previous decade.4 Cervical spondylotic myelopathy accounts for nearly 20% of cervical spine operations in the US,6 with annual hospital charges for CSM surgery exceeding 2 billion dollars per year.4 In addition, CSM is associated with substantial postsurgical outpatient expenses (for example, physician visits, imaging, physical therapy, medications). Cervical spondylotic myelopathy represents a major health burden in our society and there is a need for more original research to guide our clinical approach to this underdiagnosed condition. In this issue, we are pleased to include 11 original manuscripts that add to our understanding of CSM in several unique ways. First, we begin with a manuscript that discusses the challenge in diagnosing this clinical entity. We include manuscripts that discuss new insights that are related to imaging, monitoring, epidemiology, and minimally invasive approaches. An evidence-based review on the management of central cord syndrome is also included. The major debate in the literature over the last 50 years has been the choice of approach: ventral versus dor sal. We include a comparative study on this topic that examines ventral fusion versus laminoplasty and also a comprehensive review of the literature that compares ventral fusion to dorsal fusion for CSM. Unfortunately, randomized controlled trials for CSM have yet to be performed. Nevertheless, there exists valuable information in the original manuscripts presented here. We hope that each will provide both interest and value to the reader and that the care of patients with CSM will be improved by the information transmitted. (http://thejns.org/doi/abs/10.3171/2013.5.FOCUS13211)

The Prevalence and Phenotype of Activated Microglia/Macrophages within the Spinal Cord of the Hyperostotic Mouse (twy/twy) Changes in Response to Chronic Progressive Spinal Cord Compression: Implications for Human Cervical Compressive Myelopathy

BackgroundCervical compressive myelopathy, e.g. due to spondylosis or ossification of the posterior longitudinal ligament is a common cause of spinal cord dysfunction. Although human pathological studies have reported neuronal loss and demyelination in the chronically compressed spinal cord, little is known about the mechanisms involved. In particular, the neuroinflammatory processes that are thought to underlie the condition are poorly understood. The present study assessed the localized prevalence of activated M1 and M2 microglia/macrophages in twy/twy mice that develop spontaneous cervical spinal cord compression, as a model of human disease.MethodsInflammatory cells and cytokines were assessed in compressed lesions of the spinal cords in 12-, 18- and 24-weeks old twy/twy mice by immunohistochemical, immunoblot and flow cytometric analysis. Computed tomography and standard histology confirmed a progressive spinal cord compression through the spontaneously development of an impinging calcified mass.ResultsThe prevalence of CD11b-positive cells, in the compressed spinal cord increased over time with a concurrent decrease in neurons. The CD11b-positive cell population was initially formed of arginase-1- and CD206-positive M2 microglia/macrophages, which later shifted towards iNOS- and CD16/32-positive M1 microglia/macrophages. There was a transient increase in levels of T helper 2 (Th2) cytokines at 18 weeks, whereas levels of Th1 cytokines as well as brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and macrophage antigen (Mac) −2 progressively increased.ConclusionsSpinal cord compression was associated with a temporal M2 microglia/macrophage response, which may act as a possible repair or neuroprotective mechanism. However, the persistence of the neural insult also associated with persistent expression of Th1 cytokines and increased prevalence of activated M1 microglia/macrophages, which may lead to neuronal loss and demyelination despite the presence of neurotrophic factors. This understanding of the aetiopathology of chronic spinal cord compression is of importance in the development of new treatment targets in human disease.

Dynamic MRI Reveals Soft-Tissue Compression Causing Progressive Myelopathy in Postlaminectomy Patients: A Report of Three Cases.

Cervical spondylotic myelopathy has been reported as the most common cause of spinal cord dysfunction in individuals older than age fifty-five, although the rate of occurrence is blurred by the difficulty of making a precise and timely diagnosis. The symptoms that patients present with can be inconsistent and show high variability from patient to patient1-4. Magnetic resonance imaging (MRI) has been a beneficial tool for evaluating anteroposterior sagittal diameter, the compression ratio, and the canal-occupying ratio5,6. According to numerous biomechanical and cadaveric studies, cervical flexion results in tension forces on the spinal cord and can cause ventral spinal cord compression against osteophytes and discs. In neck extension, the cervical cord shortens, and there is an increase in the cross-sectional area of the anteroposterior diameter of the spinal cord. In addition, the space available to the spinal cord is reduced as the ligamentum flavum folds inward7,8. We report three cases of progressive myelopathy. The first patient had undergone a previous multilevel cervical laminectomy. Although an initial MRI with the neck in the neutral position showed no spinal cord compression, the patient subsequently underwent dynamic MRI with the neck in extension, which revealed flattening of the spinal cord by soft tissues buckling into the laminectomy defect. The second patient had undergone a previous cervical laminectomy and arthrodesis with lateral mass internal fixation. He presented with progressive myelopathy and exhibited cord flattening on extension MRI, similar to that seen in the first patient. The third patient presented with myelopathic symptoms, had undergone a prior multilevel laminectomy, and had been followed for a syrinx; a cervical MRI with the neck in extension revealed severe stenosis. All three patients were informed that data concerning their cases would be submitted for publication, and they …