Early neurological changes in aging cervical spine: insights from PROMIS mobility assessment

Many studies have shown that the prevalence of degenerative spinal cord compression increases with age. However, most cases at early stages are asymptomatic, and their diagnosis remains challenging. Asymptomatic cervical spinal cord compression (ASCC) patients are more likely to experience annular tears, herniated disks, and later develop symptomatic compression. Asymptomatic individuals do not typically undergo spinal cord imaging; therefore, an assessment test that is both sensitive and specific in diagnosing ASCC may be helpful. It has been demonstrated that the Patient Reported Outcome Measure Information System (PROMIS) mobility test is sensitive in detecting degenerative cervical myelopathy (DCM) symptoms. We investigated the use of the PROMIS mobility test in assessing clinical dysfunction in ASCC. In this study, 51 DCM patients and 42 age-matched healthy control (HC) were enrolled. The degree of cervical spinal cord compression was assessed using the high-resolution cervical spinal cord T2 Weighted (T2w) MRIs, which were available for 14 DCM patients. Measurements of the spinal cords anterior-posterior (AP) diameter at the region(s) that were visibly compressed as well as at different cervical spine levels were used to determine the degree of compression. The age-matched HC cohort had a similar MRI to establish the normal range for AP diameter. Twelve (12) participants in the HC cohort had MRI evidence of cervical spinal cord compression; these individuals were designated as the ASCC cohort. All participants completed the PROMIS mobility, PROMIS pain interference (PI), PROMIS upper extremity (UE), modified Japanese orthopedic association (mJOA), and neck disability index (NDI) scoring scales. We examined the correlation between the AP diameter measurements and the clinical assessment scores to determine their usefulness in the diagnosis of ASCC. Furthermore, we examine the sensitivity and specificity of PROMIS mobility test and mJOA. Compared to the HC group, the participants in the ASCC and DCM cohorts were significantly older (p = 0.006 and p < 0.0001, respectively). Age differences were not observed between ASCC and DCM (p > 0.999). Clinical scores between the ASCC and the HC group were not significantly different using the mJOA (p > 0.99), NDI (p > 0.99), PROMIS UE (p = 0.23), and PROMIS PI (p = 0.82). However, there were significant differences between the ASCC and HC in the PROMIS mobility score (p = 0.01). The spinal cord AP diameter and the PROMIS mobility score showed a significant correlation (r = 0.44, p = 0.002). Decreasing PROMIS mobility was significantly associated with a decrease in cervical spinal cord AP diameter independent of other assessment measures. PROMIS mobility score had a sensitivity of 77.3% and specificity of 79.4% compared to 59.1% and 88.2%, respectively, for mJOA in detecting cervical spinal cord compression. Certain elements of ASCC are not adequately captured with the traditional mJOA and NDI scales used in DCM evaluation. In contrast to other evaluation scales utilized in this investigation, PROMIS mobility score shows a significant association with the AP diameter of the cervical spinal cord, suggesting that it is a sensitive tool for identifying early disability associated with degenerative change in the aging spine. In a comparative analysis of PROMIS mobility test against the standard mJOA, the PROMIS mobility demonstrated higher sensitivity for detecting cervical spinal cord compression. These findings underscore the potential use of PROMIS mobility score in clinical evaluation of the aging spine.

Anatomical damages in the spinal nerve roots and the spinal cord after brachial plexus injury: descriptive study from a cohort of consecutive patients who underwent DREZ-lesioning for pain-practical implications

BACKGROUND

Systematic descriptions of anatomical damage after brachial plexus injury (BPI) at the intradural level have been scarcely reported in detail. However, considering these damages, not only in the spinal nerve roots but also in the spinal cord itself, is crucial in determining the appropriate surgical approach to restore upper limb function and address refractory pain. Therefore, the authors present a descriptive study focusing on intradural findings observed during microsurgical DREZ-lesioning.

METHODS

This study enrolled 19 consecutive patients under the same protocol. Microsurgical observation through exposure of C4 to Th1 medullary segments allowed to describe the lesions in spinal nerve roots, meninges, and spinal cord. Electrical stimulation of the ventral roots checked the muscle responses.

RESULTS

Extensive damage was observed among the 114 explored roots (six roots per patient), with only 21 (18.4%) ventral (VR) and 17 (14.9%) dorsal (DR) roots retaining all rootlets intact. Damage distribution varied, with the most frequent impairments in C6 VRs (18 patients) and the least in Th1 VRs (14 patients), while in all the 19 patients for the C6 DRs (the most frequently impaired) and in 14 patients for Th1 DRs (the less impaired). C4 roots were found damaged in 12 patients. Total or partial avulsions affected 63.3% and 69.8% of DRs and VRs, respectively, while 15.8% and 14.0% of the 114 DRs and VRs were atrophic, maintaining muscle responses to stimulation in half of those VRs. Pseudomeningoceles were present in 11 patients but absent in 46% of avulsed roots. Adhesive arachnoiditis was noted in 12 patients, and dorsal horn parenchymal alterations in 10.

CONCLUSIONS

Knowledge of intradural lesions post-BPI helps in guiding surgical indications for repair and functional neurosurgery for pain control.

Contrast-enhanced ultrasound imaging detects anatomical and functional changes in rat cervical spine microvasculature with normal aging

Normal aging is associated with significant deleterious cerebrovascular changes; these have been implicated in disease pathogenesis and increased susceptibility to ischemic injury. While these changes are well documented in the brain, few studies have been conducted in the spinal cord. Here, we utilize specialized contrast-enhanced ultrasound (CEUS) imaging to investigate age-related changes in cervical spinal vascular anatomy and hemodynamics in male Fisher 344 rats, a common strain in aging research. Aged rats (24-26 mo., N=6) exhibited significant tortuosity in the anterior spinal artery and elevated vascular resistance compared to adults (4-6 mo., N=6; tortuosity index 2.20±0.15 vs 4.74±0.45, p<0.05). Baseline blood volume was lower in both larger vessels and the microcirculation in the aged cohort, specifically in white matter (4.44e14±1.37e13 vs 3.66e14±2.64e13 CEUS bolus AUC, p<0.05). To elucidate functional differences, animals were exposed to a hypoxia challenge; whereas adult rats exhibited significant functional hyperemia in both gray and white matter (GM: 1.13±0.10-fold change from normoxia, p<0.05; WM: 1.16±0.13, p<0.05), aged rats showed no response. Immunohistochemistry revealed reduced pericyte coverage and activated microglia behavior in aged rats, which may partially explain the lack of vascular response. This study provides the first in vivo description of age-related hemodynamic differences in the cervical spinal cord.

The biomechanical effect of different types of ossification of the ligamentum flavum on the spinal cord during cervical dynamic activities

Ossification of the ligamentum flavum (OLF) is thought to be an influential etiology of myelopathy, as thickened ligamentum flavum causes the stenosis of the vertebral canal, which could subsequently compress the spinal cord. Unfortunately, there was little information available on the effects of cervical OLF on spinal cord compression, such as the relationship between the progression of cervical OLF and nervous system symptoms during dynamic cervical spine activities. In this research, a finite element model of C1-C7 including the spinal cord featured by dynamic fluid-structure interaction was reconstructed and utilized to analyze how different types of cervical OLF affect principal strain and stress distribution in spinal cord during spinal activities towards six directions. For patients with cervical OLF, cervical extension induces higher stress within the spinal cord among all directions. From the perspective of biomechanics, extension leads to stress concentration in the lateral corticospinal tracts or the posterior of gray matter. Low energy damage to the spinal cord would be caused by the high and fluctuating stresses during cervical movements to the affected side for patients with unilateral OLF at lower grades.

Longitudinal multiparametric MRI of traumatic spinal cord injury in animal models

Multi-parametric MRI (mpMRI) technology enables non-invasive and quantitative assessments of the structural, molecular, and functional characteristics of various neurological diseases. Despite the recognized importance of studying spinal cord pathology, mpMRI applications in spinal cord research have been somewhat limited, partly due to technical challenges associated with spine imaging. However, advances in imaging techniques and improved image quality now allow longitudinal investigations of a comprehensive range of spinal cord pathological features by exploiting different endogenous MRI contrasts. This review summarizes the use of mpMRI techniques including blood oxygenation level-dependent (BOLD) functional MRI (fMRI), diffusion tensor imaging (DTI), quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST) MRI in monitoring different aspects of spinal cord pathology. These aspects include cyst formation and axonal disruption, demyelination and remyelination, changes in the excitability of spinal grey matter and the integrity of intrinsic functional circuits, and non-specific molecular changes associated with secondary injury and neuroinflammation. These approaches are illustrated with reference to a nonhuman primate (NHP) model of traumatic cervical spinal cord injuries (SCI). We highlight the benefits of using NHP SCI models to guide future studies of human spinal cord pathology, and demonstrate how mpMRI can capture distinctive features of spinal cord pathology that were previously inaccessible. Furthermore, the development of mechanism-based MRI biomarkers from mpMRI studies can provide clinically useful imaging indices for understanding the mechanisms by which injured spinal cords progress and repair. These biomarkers can assist in the diagnosis, prognosis, and evaluation of therapies for SCI patients, potentially leading to improved outcomes.

Finite element modeling of the human cervical spinal cord and its applications: A systematic review

Background Context

Finite element modeling (FEM) is an established tool to analyze the biomechanics of complex systems. Advances in computational techniques have led to the increasing use of spinal cord FEMs to study cervical spinal cord pathology. There is considerable variability in the creation of cervical spinal cord FEMs and to date there has been no systematic review of the technique. The aim of this study was to review the uses, techniques, limitations, and applications of FEMs of the human cervical spinal cord.

Methods

A literature search was performed through PubMed and Scopus using the words finite element analysis, spinal cord, and biomechanics. Studies were selected based on the following inclusion criteria: (1) use of human spinal cord modeling at the cervical level; (2) model the cervical spinal cord with or without the osteoligamentous spine; and (3) the study should describe an application of the spinal cord FEM.

Results

Our search resulted in 369 total publications, 49 underwent reviews of the abstract and full text, and 23 were included in the study. Spinal cord FEMs are used to study spinal cord injury and trauma, pathologic processes, and spine surgery. Considerable variation exists in the derivation of spinal cord geometries, mathematical models, and material properties. Less than 50% of the FEMs incorporate the dura mater, cerebrospinal fluid, nerve roots, and denticulate ligaments. Von Mises stress, and strain of the spinal cord are the most common outputs studied. FEM offers the opportunity for dynamic simulation, but this has been used in only four studies.

Conclusions

Spinal cord FEM provides unique insight into the stress and strain of the cervical spinal cord in various pathological conditions and allows for the simulation of surgical procedures. Standardization of modeling parameters, anatomical structures and inclusion of patient-specific data are necessary to improve the clinical translation.

Machine-learning-based video analysis of grasping behavior during recovery from cervical spinal cord injury

Comprehensive characterizations of hand grasping behaviors after cervical spinal cord injuries are fundamental for developing rehabilitation strategies to promote recovery in spinal-cord-injured primates. We used the machine-learning-based video analysis software, DeepLabCut, to sensitively quantify kinematic aspects of grasping behavioral deficits in squirrel monkeys with C5-level spinal cord injuries. Three squirrel monkeys were trained to grasp sugar pellets from wells of varying depths before and after a left unilateral lesion of the cervical dorsal column. Using DeepLabCut, we identified post-lesion deficits in kinematic grasping behavior that included changes in digit orientation, increased variance in vertical and horizontal digit movement, and longer time to complete the task. While video-based analyses of grasping behavior demonstrated deficits in fine-scale digit function that persisted through at least 14 weeks post-injury, traditional end-point behavioral analyses showed a recovery of global hand function as evidenced by recovery of the proportion of successful retrievals by approximately 14 weeks post-injury. The combination of traditional end-point and video-based kinematic analyses provides a more comprehensive characterization of grasping behavior and highlights that global grasping performance may recover despite persistent fine-scale kinematic deficits in digit function. Machine-learning-based video analysis of kinematic digit function, in conjunction with traditional end-point behavioral analyses of grasping behavior, provide sensitive and specific indices for monitoring recovery of fine-grained hand sensorimotor behavior after spinal cord injury that can aid future studies that seek to develop targeted therapeutic interventions for improving behavioral outcomes.

Role of diffusion kurtosis imaging in evaluating microstructural changes in spinal cord of patients with cervical spondylosis

STUDY DESIGN

Analytical cross-sectional study.

PURPOSE

To study the role of diffusion kurtosis imaging (DKI) in evaluating microstructural changes in patients with cervical spondylosis.

OVERVIEW OF LITERATURE

Cervical spondylosis is a common progressive degenerative disorder of the spine. Conventional magnetic resonance imaging (MRI) can only detect the changes in the spinal cord once there are visual signal changes; hence, it underestimates the extent of the injury. Newer imaging techniques like Diffusion Tensor and Kurtosis Imaging can evaluate the microstructural changes in cervical spinal cord before the obvious signal changes appear.

METHODS

Conventional MRI, diffusion tensor imaging (DTI), and DKI scans were performed for 90 cervical spondylosis patients on 1.5-T MR Siemens Magnetom aera after obtaining informed consent. Eight patients were excluded due to poor image quality. Fractional anisotropy (FA) colour maps and diffusion kurtosis (DK) maps corresponding to spinal cord cross sections at C2-C3 intervertebral disc level (control) and at the most stenotic levels were obtained. Modified Japanese Orthopaedic Association (mJOA) scoring was used for clinical assessment of the spinal cord function. The changes in DTI and DKI parameters and their correlation with mJOA scores were analysed by SPSS 23 software.

RESULTS

In our study, mean FA and mean kurtosis (MK) values at the stenotic level (0.54, 1.02) were significantly lower than values at the non-stenotic segment (0.70, 1.27). The mean diffusivity (MD) value at the stenotic segment (1.25) was significantly higher than in the non-stenotic segment (1.09). We also observed a strong positive correlation between mJOA score and FA and MK values and a negative correlation between mJOA score and MD values, suggesting a correlation of FA, MK, and MD with the clinical severity of the disease.

CONCLUSION

Addition of DTI and DKI sequences helps in early identification of the disease without any additional cost incurred by the patient.

A sheep model of chronic cervical compressive myelopathy via an implantable wireless compression device

PURPOSE

This study aimed to establish an animal model in which we can precisely displace the spinal cord and therefore mimic the chronic spinal compression of cervical spondylotic myelopathy.

METHODS

In vivo intervertebral compression devices (IVCDs) connected with subcutaneous control modules (SCCMs) were implanted into the C2-3 intervertebral disk spaces of sheep and connected by Bluetooth to an in vitro control system. Sixteen sheep were divided into four groups: (Group A) control; (Group B) 10-week progressive compression, then held; (Group C) 20-week progressive compression, then held; and (Group D) 20-week progressive compression, then decompression. Electrophysiological analysis (latency and amplitude of the N1-P1-N2 wave in somatosensory evoked potentials, SEP), behavioral changes (Tarlov score), imaging test (encroachment ratio (ER) of intraspinal invasion determined by X-ray and CT scan), and histological examinations (hematoxylin and eosin, Nissl, and TUNEL staining) were performed to assess the efficacy of our model.

RESULTS

Tarlov scores gradually decreased as compression increased with time and partially recovered after decompression. The Pearson correlation coefficient between ER and time was r = 0.993 (p < 0.001) in Group B at 10 weeks and Groups C and D at 20 weeks. And ER was negatively correlated with the Tarlov score (r = -0.878, p < 0.001). As compression progressed, the SEP latency was significantly extended (p < 0.001), and the amplitude significantly decreased (p < 0.001), while they were both partially restored after decompression. The number of abnormal motor neurons and TUNEL-positive cells increased significantly (p < 0.001) with compression.

CONCLUSION

Our implantable and wireless intervertebral compression model demonstrated outstanding controllability and reproducibility in simulating chronic cervical spinal cord compression in animals.

DCE-MRI detected vascular permeability changes in the rat spinal cord do not explain shorter latency times for paresis after carbon ions relative to photons

BACKGROUND AND PURPOSE

Radiation-induced myelopathy, an irreversible complication occurring after a long symptom-free latency time, is preceded by a fixed sequence of magnetic resonance- (MR-) visible morphological alterations. Vascular degradation is assumed the main reason for radiation-induced myelopathy. We used dynamic contrast-enhanced (DCE-) MRI to identify different vascular changes after photon and carbon ion irradiation, which precede or coincide with morphological changes.

MATERIALS AND METHODS

The cervical spinal cord of rats was irradiated with iso-effective photon or carbon (¹²C-)ion doses. Afterwards, animals underwent frequent DCE-MR imaging until they developed symptomatic radiation-induced myelopathy (paresis II). Measurements were performed at certain time points: 1 month, 2 months, 3 months, 4 months, and 6 months after irradiation, and when animals showed morphological (such as edema/syrinx/contrast agent (CA) accumulation) or neurological alterations (such as, paresis I, and paresis II). DCE-MRI data was analyzed using the extended Toft's model.

RESULTS

Fit quality improved with gradual disintegration of the blood spinal cord barrier (BSCB) towards paresis II. Vascular permeability increased three months after photon irradiation, and rapidly escalated after animals showed MR-visible morphological changes until paresis II. After ¹²C-ion irradiation, vascular permeability increased when animals showed morphological alterations and increased further until animals had paresis II. The volume transfer constant and the plasma volume showed no significant changes.

CONCLUSION

Only after photon irradiation, DCE-MRI provides a temporal advantage in detecting early physiological signs in radiation-induced myelopathy compared to morphological MRI. As a generally lower level of vascular permeability after ¹²C-ions led to an earlier development of paresis as compared to photons, we conclude that other mechanisms dominate the development of paresis II.

High-fidelity diffusion tensor imaging of the cervical spinal cord using point-spread-function encoded EPI

Diffusion tensor imaging (DTI) of the spinal cord is technically challenging due to the size of its structure and susceptibility-induced field inhomogeneity, which impedes clinical applications. This study aimed to achieve high-fidelity spinal cord DTI with reasonable SNR and practical acquisition efficiency. Particularly, a distortion-free multi-shot EPI technique, namely point-spread-function encoded EPI (PSF-EPI), was adopted for diffusion imaging of the cervical spinal cord (CSC). The shot number can be reduced to six for sagittal scans through titled-CAIPI acceleration and partial Fourier undersampling, consequently rendering this technique beneficial in clinics. Fifteen healthy volunteers and seven patients with metallic implants underwent sagittal scans using tilted-CAIPI PSF-EPI at 3T. Unsuppressed fat signals were further removed by retrospective water/fat separation using the intrinsic chemical-shift encoded signals. Compared with multi-shot interleaved EPI method, highly accelerated PSF-EPI method provided evidently improved distortion reduction and higher consistency with anatomical references even with metallic implants. Additionally, axial DTI scans using PSF-EPI were also evaluated quantitatively, and the measured DTI metrics are similar to those obtained from the zonal oblique multi-slice EPI (ZOOM-EPI) method and reported values. The high anatomical consistency, practical scan time and quantitative reliability indicate PSF-EPI's clinical potential for CSC diffusion imaging.

Longitudinal MRI study after carbon ion and photon irradiation: shorter latency time for myelopathy is not associated with differential morphological changes

BACKGROUND

Radiation-induced myelopathy is a severe and irreversible complication that occurs after a long symptom-free latency time if the spinal cord was exposed to a significant irradiation dose during tumor treatment. As carbon ions are increasingly investigated for tumor treatment in clinical trials, their effect on normal tissue needs further investigation to assure safety of patient treatments. Magnetic resonance imaging (MRI)-visible morphological alterations could serve as predictive markers for medicinal interventions to avoid severe side effects. Thus, MRI-visible morphological alterations in the rat spinal cord after high dose photon and carbon ion irradiation and their latency times were investigated.

METHODS

Rats whose spinal cords were irradiated with iso-effective high photon (n = 8) or carbon ion (n = 8) doses as well as sham-treated control animals (n = 6) underwent frequent MRI measurements until they developed radiation-induced myelopathy (paresis II). MR images were analyzed for morphological alterations and animals were regularly tested for neurological deficits. In addition, histological analysis was performed of animals suffering from paresis II compared to controls.

RESULTS

For both beam modalities, first morphological alterations occurred outside the spinal cord (bone marrow conversion, contrast agent accumulation in the musculature ventral and dorsal to the spinal cord) followed by morphological alterations inside the spinal cord (edema, syrinx, contrast agent accumulation) and eventually neurological alterations (paresis I and II). Latency times were significantly shorter after carbon ions as compared to photon irradiation.

CONCLUSIONS

Irradiation of the rat spinal cord with photon or carbon ion doses that lead to 100% myelopathy induced a comparable fixed sequence of MRI-visible morphological alterations and neurological distortions. However, at least in the animal model used in this study, the observed MRI-visible morphological alterations in the spinal cord are not suited as predictive markers to identify animals that will develop myelopathy as the time between MRI-visible alterations and the occurrence of myelopathy is too short to intervene with protective or mitigative drugs.

High-b diffusivity of MS lesions in cervical spinal cord using ultrahigh-b DWI (UHb-DWI)

PURPOSE

The purpose of this study was to investigate UHb-rDWI signal in white matter tracts of the cervical spinal cord (CSC) and compare quantitative values between healthy control WM with both MS NAWM and MS WM lesions.

METHODS

UHb-rDWI experiments were performed on (a) 7 MS patients with recently active or chronic lesions in CSC and on (b) 7 healthy control of similar age range and gender distribution to MS subjects. All MRI data were acquired using clinical 3T MRI system. Axial high-b diffusion images were acquired using 2D single-shot DW stimulated EPI with reduced FOV and a CSC-dedicated 8 channel array coil. High-b diffusion coefficient DH was estimated by fitting the signal-b curve to a double or single-exponential function.

RESULTS

The high-b diffusivity DH values were measured as (0.767 ± 0.297) × 10-3 mm2/s in the posterior column lesions, averaged over 6 MS patients, and 0.587 × 10-3 mm2/s in the corticospinal tract for another patient. The averaged DH values of the 7 healthy volunteers from the posterior and lateral column were (0.0312 ± 0.0306) × 10-3 and (0.0505 ± 0.0205) × 10-3 mm2/s, respectively. UHb-rDWI signal-b curves of the MS patients revealed to noticeably behave differently to that of the healthy controls. The patient signal-b curves decayed with greater high-b decay constants to reach lower signal intensities relative to signal-b curves of the healthy controls.

CONCLUSION

UHb-DWI of the CSC reveals a marked difference in signal-b-curves and DH values in MS lesions compared to NAWM and healthy control WM. Based on physical principles, we interpret these altered observations of quantitative diffusion values to be indicative of demyelination. Further studies in animal models will be required to fully interpret UHb-DWI quantitative diffusion values during demyelination and remyelination.

Effects of a contusion load on spinal cord with different curvatures

The cervical spine injury is a complicated procedure in the combination of different injury loads and postures. The aim of this study is to investigate the injury mechanism considering different types of cervical curvatures subjected to contusion loads. A finite element model of a cervical spinal cord was constructed. Gray matter, white matter and pia matter were modeled and hyperelastic material properties were assigned. Convergence analysis and validation analysis were carried out. The model was simulated in 3 different spinal curvatures and loaded by 2 directions with 4 compression degrees. The maximum von Mises stress in the whole model was concentrated in the pia matter in all loading cases. When investigating spinal cord injury, the pia matter must be considered. For all three curvatures, the stress in the gray matter and white matter was higher in front-to-back loading condition than that in back-to-front loading condition. The front-to-back impact may cause a larger damage. A back-to-front load damaged the structure around the central canal and a front-to-back contusion load damaged the anterior horn of the spinal cord at most time. From the view of the maximum stress, the lordotic curvature did not show significant buffering effect. However, the pathological curvature had large areas affected and the lordotic curvature showed some benefits to some degree from the view of stress distribution.

Idiopathic Hypertrophic Spinal Pachymeningitis with Spinal Cord Lesion: A Case Report

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a rare, diffuse inflammatory fibrosis of the dura mater that can lead to spinal cord compression. Though the optimal treatment is controversial, some reports recommend decompressive surgery and postoperative steroid therapy. However, we encountered a case of pachymeningitis that worsened after decompressive surgery. A 79-year-old woman presented with gait disturbance and bilateral lower extremity weakness that began 6 months prior. She had radiating pain on the C5 and T1 dermatomes and clumsiness in both hands. Magnetic resonance imaging (MRI) revealed diffuse thickening of the posterior longitudinal ligament of C6 to T4/5 and ligamentum flavum of C3/4 to T4/5, causing central canal stenosis and compressive myelopathy. She underwent posterior decompressive laminectomy from C4 to T1 total (T2 subtotal) and cervicothoracic screw fixation. During surgery, we found severe adhesion of the posterior longitudinal ligament and ligamentum flavum to the dura mater. Chronic inflammation with fibrosis and lymphoplasmacytic infiltration were present. After surgery, the patient's motor weakness worsened. Despite steroid treatment, her symptom severity fluctuated. Follow-up MRI obtained 3 months postoperation revealed high signal intensity from C5 to T2, possibly indicating aggravated compressive myelopathy. Thus, in this case, decompressive surgery and steroid therapy were detrimental.

Evaluation of microstructural changes in spinal cord of patients with degenerative cervical myelopathy by diffusion kurtosis imaging and investigate the correlation with JOA score

Background

To explore the feasibility of the metrics of diffusion kurtosis imaging (DKI) for investigations of the microstructural changes of spinal cord injury in patients with degenerative cervical myelopathy (DCM) and the correlation between Japan Orthopaedic Association (JOA) scores and DKI metrics.

Methods

Fifty-seven patients with DCM and 38 healthy volunteers underwent 3.0 T magnetic resonance (MR) imaging with routine MRI sequences and DKI from echo-planar imaging sequence. Based on the JOA score, DCM patients were divided into four subgroups. DKI metrics of the DCM group and control group were obtained and compared, separately for the white matter (WM) and the gray matter (GM).

Results

The FA values in WM were significantly lower (P = 0.020) in the DCM group than in the control group. The MK values in GM were lower (P = 0.011) in the DCM group than in the control group. The MD values in WM were significantly higher (P = 0.010) in the DCM group than in the control group. In GM, the JOA score was positively correlated with the MK values (r = 0.768, P < 0.05). In the WM, the JOA score was positively correlated with the FA values (r = 0.612, P < 0.05).

Conclusion

DKI provides quantitive evaluation to the characters of microstructure of the spinal cord damage in patients with DCM compared to conventional MR. MK values can reflect microstructural abnormalities of gray matter of the cervical spinal cord and provide more information beyond that obtained with routine diffusion metrics. In addition, MK values of GM and FA values of WM may as a be highly sensitive biomarker for the degree of cervical spinal cord damage.

Anterior Approach Combined with Endoscopic Fluorescence Video Angiography for a Cervical Perimedullary Arteriovenous Fistula

BACKGROUND

Perimedullary arteriovenous fistulas (pAVFs) of the anterior cervical spinal cord are rare and difficult to eradicate by surgery because of the limitations of the approach routes. Because of the anatomic relationships, an anterior approach with corpectomy can provide direct observation. However, a narrow corridor to the lesion is the drawback of this approach. Therefore, to overcome this limitation, we introduced angled endoscopes integrated with fluorescence video angiography to observe the real-time blood flow.

CASE DESCRIPTION

A 47-year-old woman was incidentally found to have a pAVF fed by multiple radicular arteries, and she underwent direct surgery via the anterior approach. Although observation of the entire lesion was difficult with the microscope alone, the introduction of the angled endoscope made it possible to observe the lateral portion of the spinal cord hidden behind the dura mater. Furthermore, endoscopic fluorescein video angiography visualized residual fine feeding arteries that were then electrocoagulated, which contributed to complete obliteration of the shunt.

CONCLUSIONS

The anterior approach with endoscopic assistance is a reasonable strategy for the treatment of ventrally located cervical pAVFs. Furthermore, integration of a fluorescence video angiography system with the endoscope enables confirmation of the complicated real-time hemodynamics of the pAVFs, contributing to reliable treatment.

Nasogastric tube in anterior cervical spine surgery, is it necessary?

Background:

The aim of this article was to verify the utility of nasogastric (NG) tube in primary anterior cervical surgeries. Palpating and identifying the NG tube introduced during induction is one of the ways of preventing esophageal injuries during surgery. It may also be used as a conduit for postoperative feeding. However, the use of NG tube is not without complications. Esophageal perforation is one of them, with an incidence of 0.3%.

Materials and Methods:

A retrospective observational study was performed of patients who underwent a primary anterior cervical spine surgery from January 2007 to July 2017 by a single surgeon. The indications were degenerative, trauma, infection, and neoplasia. NG tube was avoided in all cases. The patients were followed for 6 months.

Results:

Our study included 356 patients (201 males and 155 females), with a mean age of 43.6 years (18–92 years) and a mean follow-up of 6 months. We had only one case of esophageal perforation (0.28%) attributed to a traumatic burst fracture.

Conclusions:

This study indicates that the use of a NG tube in primary anterior cervical spine surgery can be avoided. Comprehensive knowledge of anatomy and meticulous dissection may avoid the disastrous complication of esophageal rupture. This way the discomfort and complications associated with NG tube can be avoided.

Intramedullary Metastasis to the Cervical Spinal Cord from Malignant Pleural Mesothelioma: Review of the Literature and Case Reports

Context:

Malignant mesothelioma is an aggressive tumor; median survival of patients following diagnosis is 12 months.

Aims:

Pleural malignant mesothelioma tends to spread along preexisting tissue planes and has the rare ability to spread along the nerve root into the spinal cord. In our case, there is an evidence of exceptional direct hematogenous spread to the spinal cord by the spinal branch of the intercostal arteries or the veins of Batson's plexus.

Settings and Design:

The authors report a case of intramedullary hematogenous metastasis to the cervical spinal cord from malignant mesothelioma, with a review of the literature.

Materials and Methods:

A 68-year-old male was admitted to our department because of a slowly progressive mild weakness of both low extremities, more pronounced on the left side. The patient has been treated for a malignant mesothelioma with left thoracotomy and subsequently underwent radiotherapy. Magnetic resonance imaging of the cervical-thoracic spine revealed a contrast-enhancing intramedullary expansive lesion of the left half of the spinal cord at the C6–C7 level.

Results:

The patient underwent surgical treatment through a C6–C7 laminectomy. Through a median posterior spinal cord incision, an intramedullary grayish lesion was completely removed. The paraparesis progressively improved and 20 days after surgery, the patient had regained normal lower extremity function.

Conclusions:

Malignant mesothelioma can spread to the spinal canal by the direct extension through the intervertebral foramina, by hematogenous spread to the spinal meninges, and by perineural growth along a single nerve root. The cleavage plane of the tissue may determine whether a successful gross total resection can be achieved with a good outcome for the patient.

Respiratory resetting elicited by single pulse spinal stimulation

Intraspinal microstimulation (ISMS) can effectively activate spinal motor circuits, but the impact on the endogenous respiratory pattern has not been systematically evaluated. Here we delivered ISMS in spontaneously breathing adult rats while simultaneously recording diaphragm and external intercostal electromyography activity. ISMS pulses were delivered from C2-T1 along two rostrocaudal tracts located 0.5 or 1 mm lateral to midline. A tungsten electrode was incrementally advanced from the dorsal spinal surface and 300μs biphasic pulses (10-90 μA) were delivered at depth increments of 600 μm. Dorsal ISMS often produced fractionated inspiratory bursting or caused early termination of the inspiratory effort. Conversely, ventral stimulation had no discernable impact on respiratory resetting. We conclude that ISMS targeting the ventral spinal cord is unlikely to directly alter the respiratory rhythm. Dorsal ISMS, however, may terminate the inspiratory burst through activation of spinobulbar pathways. We suggest that respiratory patterns should be included as an outcome variable in preclinical studies of ISMS.

Differences in distribution of anterior segmental medullary arteries in the cervical and thoracolumbar spinal cord: the "inseln" were characteristics in the cervical spinal cord

Anterior segmental medullary arteries cause spinal cord infarction due to circulatory disturbance, but are difficult to identify in diagnostic images. This study investigated the arterial distribution from the cervical to lumbar segments of the dissecting spinal cord in 100 cadavers. The 488 arteries were distributed from C2 to L2, of which 252 arteries from C2 to C8 were slightly dominant on the right side, but 236 arteries from Th1 to L2 were obviously dominant on the left side. This change occurred at the C8 and Th1 segments. Of the 252 arteries, 37.30% (94 arteries) were divided into ascending and descending branches. Both branches formed loops by anastomosis with the anterior spinal arteries. The loops, called "insel", have an unclear distribution and form. We focused on the features of inseln and found 63 of them in the cervical spinal cord of 45 cadavers. Their numbers and forms differed depending on whether the 94 arteries were bilateral (type A) or unilateral (type B), but the long axis of the insel was limited to one cervical segment. 90.63% of type A were bilateral at the same level, and 70% of type B were on the right side. The former always formed the insel. Further, 94 arteries were distributed from C2 to C7, 82.98% of which were concentrated at C3-C5. Therefore, the arterial blood supply of the spinal cord may differ between the cervical spinal cord and the thoracolumbar cord.

Effect of segmentation from different diffusive metric maps on diffusion tensor imaging analysis of the cervical spinal cord

Background

Segmentation is a crucial and necessary step in diffusion tensor imaging (DTI) analysis of the cervical spinal cord. In existing studies, different diffusive metric maps [B0, fractional anisotropy (FA) and axial diffusivity (AD) maps] have been involved in the segmentation of tissues of the cervical spinal cord. The selection of a diffusive metric map for segmentation may affect the accuracy of segmentation and then affect the validity and effectiveness of the extracted diffusive features. However, there are few discussions on this problem. Therefore, this study would like to examine the effect of segmentation based on different diffusive metric maps for DTI analysis of the cervical spinal cord.

Methods

Twenty-nine healthy subjects and thirty patients with cervical spondylotic myelopathy (CSM) were finally included in this study. All subjects accepted DTI scanning at cervical levels from C2 to C7/T1. For healthy subjects, all cervical levels were included for analysis; while, for each patient, only one compressed cervical level was included. After DTI scanning, DTI metrics including B0, FA, AD, radial diffusivity (RD) and mean diffusivity (MD) were calculated. The evaluation was performed to B0, FA and AD maps from two aspects. First, the accuracy of segmentation was evaluated via a comparison between segmentation based on each diffusive metric map and segmentation based on an average image, which was acquired by averaging B0, FA, AD, RD and MD maps. The segmentation was achieved by a semi-automatic segmentation process, and the similarity between two segmentation results was denoted by the intersection of the union (IOU). Second, the diversity of extracted diffusive features was equalized as their performance in the classification of image pixels of different regions of interest (ROIs) and then was evaluated by mutual information (MI) and area under the curve (AUC). One-way ANOVA and Bonferroni's post hoc tests were applied to compare the evaluation results.

Results

One-way ANOVA suggested that there were differences (P<0.001) in IOU, MI and AUC values among the three diffusive metric maps for both healthy subjects and patients. The post-hoc tests further indicated that FA performed the best (P<0.001), i.e., the most substantial accuracy of segmentation and the highest diversity in extracted diffusive features.

Conclusions

Different evaluation results had been observed for segmentation based on different diffusive metric maps, suggesting the necessity of selection of diffusive metric maps for segmentation in DTI analysis of the cervical spinal cord. Moreover, FA map is suggested for segmentation due to its best performance in the evaluation.

Synergistic influences of sensory and central stimuli on non-voluntary rhythmic arm movements

In recent years, neuromodulation of the cervical spinal circuitry has become an area of interest for investigating rhythmogenesis of the human spinal cord and interaction between cervical and lumbosacral circuitries, given the involvement of rhythmic arm muscle activity in many locomotor tasks. We have previously shown that arm muscle vibrostimulation can elicit non-voluntary upper limb oscillations in unloading body conditions. Here we investigated the excitability of the cervical spinal circuitry by applying different peripheral and central stimuli in healthy humans. The rationale for applying combined stimuli is that the efficiency of only one stimulus is generally limited. We found that low-intensity electrical stimulation of the superficial arm median nerve can evoke rhythmic arm movements. Furthermore, the movements were enhanced by additional peripheral stimuli (e.g., arm muscle vibration, head turns or passive rhythmic leg movements). Finally, low-frequency transcranial magnetic stimulation of the motor cortex significantly facilitated rhythmogenesis. The findings are discussed in the general framework of a brain-spinal interface for developing adaptive central pattern generator-modulating therapies.

Intramedullary cervical abscess mimicking a spinal cord tumor in a 10-year-old girl: a case-based review

BACKGROUND

Intramedullary spinal cord abscesses (ISCA) are a rare pathological entity with very few cases reported in the world and may be confused with an intramedullary tumor. Cervical location is the least frequently affected, except for cryptogenic spread, mostly seen in adult patients. Meticulous study of contrast-enhanced MRI pictures has a key role in the diagnosis.

METHOD AND RESULTS

We present a case of a spontaneous cervical ISCA, mimicking a spinal cord tumor, in a pediatric patient with good outcome. A review of the literature shows that this is a life-threatening condition with high chances of rupture and subsequent meningitis.

CONCLUSIONS

We point out that if a solitary cervical spinal cord lesion is surrounded by significant medullar edema associated with fast onset of symptoms, fever, and elevation of WBC, the possibility of a spinal cord abscess should be considered prior to surgery.

Structural and functional identification of two distinct inspiratory neuronal populations at the level of the phrenic nucleus in the rat cervical spinal cord

The diaphragm is driven by phrenic motoneurons that are located in the cervical spinal cord. Although the anatomical location of the phrenic nucleus and the function of phrenic motoneurons at a single cellular level have been extensively analyzed, the spatiotemporal dynamics of phrenic motoneuron group activity have not been fully elucidated. In the present study, we analyzed the functional and structural characteristics of respiratory neuron population in the cervical spinal cord at the level of the phrenic nucleus by voltage imaging, together with histological analysis of neuronal and astrocytic distribution in the cervical spinal cord. We found spatially distinct two cellular populations that exhibited synchronized inspiratory activity on the transversely cut plane at C4–C5 levels and on the ventral surface of the mid cervical spinal cord in the isolated brainstem–spinal cord preparation of the neonatal rat. Inspiratory activity of one group emerged in the central portion of the ventral horn that corresponded to the central motor column, and the other appeared in the medial portion of the ventral horn that corresponded to the medial motor column. We identified by retrogradely labeling study that the anatomical distributions of phrenic and scalene motoneurons coincided with optically detected central and medial motor regions, respectively. Furthermore, we anatomically demonstrated closely located features of putative motoneurons, interneurons and astrocytes in these regions. Collectively, we report that phrenic and scalene motoneuron populations show synchronized inspiratory activities with distinct anatomical locations in the mid cervical spinal cord.

Endoscopic partial corpectomy using anterior decompression for cervical myelopathy

Symptomatic ventral cervical cord compressions have been treated by anterior discectomy with fusion, anterior corpectomy and fusion, discectomy with an artificial disc, and minimally invasive techniques. There are complications associated with the fusion procedure, especially when a long segment fusion is undertaken. Partial removal of the vertebral body without fusion could help in avoiding fusion and its associated complications. We are describing the detailed surgical technique, indications, limitations, and early results of endoscopic partially corpectomy. The detailed endoscopic technique of how to remove minimal portion of the anterior and middle part of the vertebra with the removal of compressing posterior portion is described. To the best of the author's knowledge, this procedure has not been described in the literature till date. This technique has the advantages of preservation of most of the vertebral body and disc. The stability of the spine is maintained without the patient having to undergo the additional procedure of spinal fusion. There is a shorter length of hospital stay. The technique can also be used in special conditions, such as when a migrated disc behind the vertebral body or any bony compression opposite the vertebral body is encountered. It avoids injury to the longus colli muscles and damage to most of the annulus fibrosis. It preserves motion segments at the operated and adjacent segments without any significant decrease in the disc and vertebral height. A relatively short follow-up and the experience in a relatively small number of patients till now, are the limitations to the widespread use of this technique. Although long-term follow-up of this procedure in a large number of patients is not currently available, endoscopic partial corpectomy seems to be an effective and an alternative method for dealing with anteriorly located cervical compression. Long-term follow-up in a large number of patients is required to assess for the safety and effectiveness of the procedure.

High Cervical Spinal Cord Compression Associated with Anomaly of Bilateral Vertebral Arteries

BACKGROUND

Anomalies of the vertebral arteries are rare and usually detected incidentally. However, very rarely, they can manifest with clinical symptoms. We describe such a symptomatic case of high cervical spinal cord compression associated with persistent C2 segmental arteries.

CASE DESCRIPTION

A 67-year-old man presented with a 5-year history of worsening left-sided weakness and gait disturbance. Magnetic resonance imaging, 3-dimensional computed tomography, and digital subtraction angiography revealed anomalous courses of the vertebral arteries, which compressed the cervical spinal cord at the C1 level from both sides. Interestingly, the left vertebral artery had fenestration, which supposedly reflected that the intradural paramedian longitudinal axis had developmentally persisted until more distally on the left. Microvascular decompression was performed to transpose the offending vertebral arteries. With vascular tapes made of polyglycolic acid sheets and fascia, the vertebral arteries compressing the cervical spine were anchored to the dura mater of the vertebral arch. This maneuver effectively relieved the neurovascular conflict created by the bilateral anomalous vertebral arteries, and the patient's myelopathy improved after surgery. To our knowledge, this is the first report to clearly demonstrate this combination of vertebral artery anomalies causing clinical symptoms and its successful treatment by microvascular decompression.

CONCLUSIONS

Transposition of the vertebral artery by anchoring to the dura mater of the vertebral arch could be an effective and safe option for these disease conditions.

Proton Density Fat Suppressed MRI in 3T Increases the Sensitivity of Multiple Sclerosis Lesion Detection in the Cervical Spinal Cord

PURPOSE

Considering the number of multiple sclerosis (MS) patients referred for clinical spinal cord imaging, the optimization of imaging protocols plays a crucial role. We aimed to evaluate the use of proton density (PD) turbo spin-echo (TSE) with spectral attenuated inversion recovery (SPAIR) fat suppression and compare it with the currently recommended T2-TSE-SPAIR in sagittal plane in cervical spinal cord imaging.

METHODS

In this study 35 MS patients with clinically suspected or known spinal cord lesions were scanned on a 3.0T magnetic resonance imaging (MRI) system. In addition to the routine protocol, PD-TSE-SPAIR sequences were obtained to quantitatively and qualitatively evaluate lesion detectability and image quality compared to T2-TSE-SPAIR sequences. Quantitative analysis was based on measurements of lesion-to-cord contrast ratio (LCCR), lesion contrast-to-noise ratio (LCNR) and lesion dimensions and the qualitative analysis on ranking with a predetermined score scale. The presence of lesions in these sequences was verified in axial T2 multi-echo gradient echo images.

RESULTS

In quantitative analysis, the lesions on PD-TSE-SPAIR had statistically significantly higher contrast (p < 0.05), according to the statistical test of LCCR, LCNR calculated contrast and measured lesion dimensions. Qualitative analyses were congruent with quantitative results; the median rank of PD-TSE-SPAIR was significantly higher than T2-TSE-SPAIR (p < 0.05). Of the 34 detected lesions 9 (26%) were not visualized in T2-TSE-SPAIR sequence.

CONCLUSION

Considering its superiority in contrast ratios and lesion dimensions when compared to T2-TSE-SPAIR in both qualitative and quantitative analyses, we therefore recommend PD-TSE-SPAIR as a pivotal sequence to evaluate demyelinating spinal cord lesions at 3T.

Spinal cord microstructure integrating phase-sensitive inversion recovery and diffusional kurtosis imaging

PURPOSE

The aim of this prospective study was to determine the feasibility in terms of repeatability and reproducibility of diffusional kurtosis imaging (DKI) for microstructural assessment of the normal cervical spinal cord (cSC) using a phase-sensitive inversion recovery (PSIR) sequence as the anatomical reference for accurately defining white-matter (WM) and gray-matter (GM) regions of interests (ROIs).

METHODS

Thirteen young healthy subjects were enrolled to undergo DKI and PSIR sequences in the cSC. The repeatability and reproducibility of kurtosis metrics and fractional anisotropy (FA) were calculated in GM, WM, and cerebral-spinal-fluid (CSF) ROIs drawn by two independent readers on PSIR images of three different levels (C1-C4). The presence of statistically significant differences in DKI metrics for levels, ROIs (GM, WM, and CSF) repeatability, reproducibility, and inter-reader agreement was evaluated.

RESULTS

Intra-class correlation coefficients between the two readers ranged from good to excellent (0.75 to 0.90). The inferior level consistently had the highest concordance. The lower values of scan-rescan variability for all DKI parameters were found for the inferior level. Statistically significant differences in kurtosis values were not found in the lateral white-matter bundles of the spinal cord.

CONCLUSION

The integration of DKI and PSIR sequences in a clinical MR acquisition to explore the regional microstructure of the cSC in healthy subjects is feasible, and the results obtainable are reproducible. Further investigation will be required to verify the possibility to translate this method to a clinical setting to study patients with SC involvement especially in the absence of MRI abnormalities on standard sequences.

Clinical Outcomes of Cervical Laminoplasty: Results at Two Years

BACKGROUND

Laminoplasty is an established treatment for cervical myelopathy. Multiple variations have emerged, many advocating the use of allograft, but controversy persists.

OBJECTIVE

To assess medium-term clinical outcomes in patients who underwent laminoplasty with autograft at our institution.

METHODS

Thirty-two consecutive patients (19 male, 13 female, average age 66 yr) from our prospective outcome registry that underwent cervical laminoplasty between 2009 and 2013 were reviewed. Computed tomography (CT) scan was performed immediately postoperatively and at 6-mo follow-up. Parameters included patient perception of outcome, Nurick score, Neck Disability Index (NDI), visual analog scale for neck pain, and SF-36.

RESULTS

On retrospective analysis, all patients felt improved at 3 mo postoperatively; at 2 yr, this rate was 91%. Improvements were seen in Nurick scores, from 3.16 ± 0.9 preoperatively to 1.94 ± 0.8 at 2 yr; NDI score from 28.7% ± 9% preoperatively to 20.8% ± 9.6% at 2 yr; visual analog scale from 2.8 ± 1.2 preoperatively to 1.7 ± 0.9 at 2 yr; and SF-36 physical component summary from 27.9 ± 10 preoperatively to 37.8 ± 11.9 at 2 yr. All values reached significance at all follow-up points ( P < .05) with the exception of 6-mo NDI values ( P = .062). No C5 palsy, graft complications, or reclosure was observed in any patient during the follow-up period.

CONCLUSION

Laminoplasty with autograft is a safe and effective method to treat cervical myelopathy, with good medium-term clinical outcome. No reclosures were observed. Bony fusion was seen in all cases on CT scan. Our study found good outcomes in the performance of open-door laminoplasty without hardware, in the treatment of cervical stenosis.

Analysis of the diffusion tensor imaging parameters of a normal cervical spinal cord in a healthy population

BACKGROUND

Diffusion tensor imaging (DTI) shows great advantage in the diagnosis of brain diseases, including cervical spinal cord (CSC) disease. This study aims to obtain the normal values of the DTI parameters for a healthy population and to establish a baseline for CSC disease diagnosis using DTI.

METHODS

A total of 36 healthy adults were subjected to magnetic resonance imaging (MRI) for the entire CSC using the Siemens 3.0 T MR System. Sagittal DTI acquisition was carried out with a single-shot spin-echo echo-planar imaging (EPI) sequence along 12 non-collinear directions. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were determined at different cervical levels using a region of interest (ROI) method, following which they were correlated with parameters, like age and sex. Further, diffusion tensor tracking (DTT) was carried out to reconstruct the white matter fiber bundles of the CSC.

RESULTS

The full and complete fiber bundle structure of a normal CSC was confirmed in both the T2-weighted and DTI images. The FA and ADC values were significantly negatively correlated with each other and showed strongly negative and positive correlations with age, respectively, but not with sex. Additionally, there was no significant difference between the FA and the ADC values at different cervical levels.

CONCLUSION

The DTI technique can act as an important supplement to the conventional MRI technique for CSC observation. Moreover, the FA and ADC values can be used as sensitive parameters in the DTI study on the CSC by taking the effects of age into consideration.

Axial MR diffusion tensor imaging and tractography in clinical diagnosed and pathology confirmed cervical spinal cord astrocytoma

OBJECTIVE

To evaluate the diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) features of cervical spinal cord astrocytoma.

METHODS

Eleven patients with cervical spinal cord astrocytomas and 10 healthy volunteers were recruited in this study. Conventional magnetic resonance imaging (MRI) and axial DTI were performed on a 3.0T MRI system. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values for the lesions were measured. DTT was performed using the principal diffusion direction method.

RESULTS

ADC values of the lesions and the normal-appearing tissue around the tumour (NATAT) on T2-weighted imaging (T2WI) increased. The ADC values of the lesions were higher. The FA values of the lesions and the NATAT decreased significantly, with the lesions having lower FA values. The RD value (1.36±0.49) of the tumours was significantly higher than those found in the healthy controls, but similar for the AD value (1.84±0.56). There were no differences in ADC or FA values between lesions and NATAT in McCormick Type I vs. Type II patients. Based on the DTT, 7 patients with solid mass tumours were classified as Type I. One patient with a solid mass, 2 patients with cystic degeneration inside the lesions, and 1 patient with a cyst around the mass were classified as Type II.

CONCLUSIONS

FA values of the cervical spinal cord astrocytoma decreased, but the ADC values increased. DTI was sensitive for the evaluation of pathological changes that could not be visualized on T2WI. Our preliminary study indicates that DTT can be used to guide operation planning, and that axial images of DTT may be more valuable.

Factors affecting outcome of acute cervical spine injury: A prospective study

Background:

Injury to the spine and spinal cord is one of the common cause of disability and death. Several factors affect the outcome; but which are these factors (alone and in combination), are determining the outcomes are still unknown. The aim of the study was to evaluate the factors influencing the outcome following acute cervical spine injury.

Materials and Methods:

A prospective observational study at single-center with all patients with cervical spinal cord injury (SCI), attending our hospital within a week of injury during a period of October 2011 to July 2013 was included for analysis. Demographic factors such as age, gender, etiology of injury, preoperative American Spinal Injury Association (ASIA) grade, upper (C2-C4) versus lower (C5-C7) cervical level of injury, imageological factors on magnetic resonance imaging (MRI), and timing of intervention were studied. Change in neurological status by one or more ASIA grade from the date of admission to 6 months follow-up was taken as an improvement. Functional grading was assessed using the functional independence measure (FIM) scale at 6 months follow-up.

Results:

A total of 39 patients with an acute cervical spine injury, managed surgically were included in this study. Follow-up was available for 38 patients at 6 months. No improvement was noted in patients with ASIA Grade A. Maximum improvement was noted in ASIA Grade D group (83.3%). The improvement was more significant in lower cervical region injuries. Patient with cord contusion showed no improvement as opposed to those with just edema wherein; the improvement was seen in 62.5% patients. Percentage of improvement in cord edema ≤3 segments (75%) was significantly higher than edema with >3 segments (42.9%). Maximum improvement in FIM score was noted in ASIA Grade C and patients who had edema (especially ≤3 segments) in MRI cervical spine.

Conclusions:

Complete cervical SCI, upper-level cervical cord injury, patients showing MRI contusion, edema >3 segments group have worst improvement in neurological status at 6 months follow-up.

Scissors stab wound to the cervical spinal cord at the craniocervical junction

BACKGROUND CONTEXT

Stab wounds resulting in spinal cord injury of the craniocervical junction are rare. A scissors stab wound to the cervical spinal cord has been reported only once in the literature.

PURPOSE

This paper aimed to report a case of Brown-Séquard-plus syndrome in an 8-year-old boy secondary to a scissors stab wound at the craniocervical junction.

STUDY DESIGN

Case report and review of the literature.

PATIENT SAMPLE

Case report of an 8-year-old boy accidentally stabbed in the neck by scissors, which were thrown as a dart.

METHODS

The case study of an 8-year-old boy who was hospitalized because of a scissors stab wound at the craniocervical junction. The patient developed Brown-Séquard-plus syndrome on the left side of the body. Magnetic resonance imaging revealed a laceration of the spinal cord at the craniocervical junction with cerebrospinal fluid leakage. Careful cleansing and interrupted sutures of the wounds were performed to prevent cerebrospinal fluid leakage. Rehabilitation therapy was performed 2 days later.

RESULTS

A follow-up examination revealed complete recovery of the neurologic deficit 8 months post-injury.

CONCLUSION

Treatment of scissors stab wounds to the cervical spinal cord, whether conservative management or thorough surgical exploration, should be individualized based on history, examination, and imaging. As shown in this case report, despite conservative management, complete recovery, which was unexpected, was attributed to the initial mild laceration of the spinal cord and ipsilateral spinal cord functional compensation.

Cervical Spine Chondroma Compressing Spinal Cord: A Case Report and Literature Review

Chondromas are benign tumor of cartilaginous tissue that is rarely found in spine. The authors document a rare case of a 72 year old male patient with a cervical spinal chondroma compressing the spinal cord. The patient had symptoms of motor and sensory deficits, dysphagia and dysarthria. C1 and C2 laminotomy was done and the spinal tumor was removed. The patient gradually recovered from his previous symptom after the surgery.

Short-latency afferent inhibition in chronic spinal cord injury

Background

Short-latency afferent inhibition (SAI) results when somatosensory afferent input inhibits the corticospinal output from primary motor cortex (M1). The present study examined SAI in the flexor carpi radialis (FCR) muscle in individuals with spinal cord injury (SCI) and uninjured controls.

Methods

Short-latency afferent inhibition (SAI) was evoked by stimulating the median nerve at the elbow at intervals of 15, 20 and 25 ms in advance of a transcranial magnetic stimulation (TMS) pulse over M1. SAI was tested with the FCR at rest and also during ~20% of maximum voluntary contraction. Corticospinal output was assessed through measuring both motor thresholds and motor evoked potential (MEP) recruitment curves. The afferent volley was assessed via the N20–P25 amplitude of the somatosensory evoked potential (SEP) and the amplitude of sensory nerve action potentials (SNAP) recorded over the median nerve at the elbow.

Results

SAI is reduced in SCI in both the contracted and non-contracted FCR muscle. MEP recruitment curves and thresholds were decreased in SCI only in the active state and not the resting state. N20–P25 amplitude was similar between groups in both the resting and active states although SNAP was significantly reduced in SCI at rest.

Conclusions

We conclude that reduced SAI in SCI is likely attributed to neuroplasticity altering the intrinsic M1 circuitry mediating SAI and/or reduced afferent input traversing a direct thalamocortical route to M1. These data provide a new avenue of research aimed at identifying therapeutic approaches to alter SAI to improve upper limb function in individuals with SCI.

The possible meaning of fractional anisotropy measurement of the cervical spinal cord in correct diagnosis of amyotrophic lateral sclerosis

Diagnosis of amyotrophic lateral sclerosis (ALS) is based on clinical criteria and electrophysiological tests (electromyography, and transcranial magnetic stimulation). In the search for ALS biomarkers, the role of imaging procedures is currently emphasized, especially modern MR techniques. MR procedures were performed on 15 ALS patients and a sex- and age-matched control group. The MR examinations were performed with a 1.5-T MR unit, and the protocol consisted of sagittal T1-weighed images, sagittal and axial T2-weighed images, and sagittal T2-weighed FAT SAT images followed by an axial diffusion tensor imaging (DTI) sequence of the cervical spinal cord. FA values in individual segments of the cervical spinal cord were decreased in the ALS group in comparison with the control group. After comparing FA values for anterior, posterior, and lateral corticospinal columns, the greatest difference was observed between the C2 and C5 segments. Spinal cord assessment with the use of FA measurements allows for confirmation of the motor pathways lesion in ALS patients. The method, together with clinical criteria, could be helpful in ALS diagnosis, assessment of clinical course, or even the effects of new drugs. The results also confirmed the theory of the generalized character of ALS.

Role of MK2 signaling pathway in the chronic compression of cervical spinal cord

OBJECTIVE

In this study, chronic compression of cervical spinal cord was introduced into twy/twy mice and the role of MK2 signaling pathway was investigated in this disease.

METHODS

twy/twy mice aged 6-24 weeks were used and the inflammatory response in the cervical spinal cord was observed. The Institute of Cancer Research (ICR) mice were used as controls. MK2 inhibitor (PF-3644022, 30 mg/kg) was administered intragastrically to twy/twy mice. The motor behavior was firstly observed in these three groups by Catwalk gait analysis. And the cervical spinal cord between C2 and C3 of vertebral segments was analyzed by MRI and Western blot assay.

RESULTS

The stride length of paws and interlimb coordination reduced in twy/twy mice. However, at 4 weeks after PF-3644022 treatment, a marked improvement was observed in the motor function. The expressions of inflammation related factors (such as IL-1β, NF-κB, TNF-α, MK2 and p-MK2) and apoptosis related proteins (such as cleaved caspase-8 and bax/bcl-2) in the spinal cord of twy/twy mice significantly increased as compared to controls, but 4-week treatment with PF-3644022 markedly reduced the expressions of these factors and apoptotic proteins in the cervical spinal cord.

CONCLUSION

MK2 signaling pathway is involved in the chronic compression induced inflammation of the cervical spinal cord. Thus, to inhibit the MK2 pathway may used to improve the outcome and prevent the deterioration of neurological dysfunction.

Normal Values of Diffusion Tensor Magnetic Resonance Imaging Parameters in the Cervical Spinal Cord

Study Design

Prospective study.

Purpose

We evaluated the usefulness of diffusion tensor imaging (DTI) in diagnosing patients with cervical myelopathy by determining the accuracy of normal DTI parameter values.

Overview of Literature

DTI can visualize white matter tracts in vivo and quantify anisotropy. DTI is known to be more sensitive than conventional magnetic resonance imaging (MRI) in detecting subtle pathological changes of the spinal cord.

Methods

A total of 31 normal subjects (13 men and 18 women; age, 23-87 years; mean age, 46.0 years) were included in this study. The patients had no symptoms of myelopathy or radiculopathy. A Philips Achieva 3-Tesla MRI with SE-type Single Shot EPI was used to obtain diffusion tensor images. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured as DTI parameters on axial sections of several cervical levels. Subjects were divided into two groups: >40 years (n=16) and ≤40 years (n=15). A paired t-test was used to compare significant differences between the groups. ADC and FA values were most stable on axial sections.

Results

For all subjects, mean ADC and FA values were 1.06±0.09×10^-3 mm²/sec and 0.68±0.05, respectively. ADC was significantly higher in subjects >40 years of age than in those ≤40 years. There was no significant difference in FA values between the two groups. The mean ADC value was significantly higher in normal subjects >40 years of age than in those ≤40 years.

Conclusions

It is important to consider age when evaluating cervical myelopathy by DTI.

GLT1 overexpression in SOD1(G93A) mouse cervical spinal cord does not preserve diaphragm function or extend disease

Amyotrophic lateral sclerosis (ALS) is characterized by relatively rapid degeneration of both upper and lower motor neurons, with death normally occurring 2-5years following diagnosis primarily due to respiratory paralysis resulting from phrenic motor neuron (PhMN) loss and consequent diaphragm denervation. In ALS, cellular abnormalities are not limited to MNs. For example, decreased levels and aberrant functioning of the major central nervous system (CNS) glutamate transporter, GLT1, occur in spinal cord and motor cortex astrocytes of both humans with ALS and in SOD1(G93A) rodents, a widely studied ALS animal model. This results in dysregulation of extracellular glutamate homeostasis and consequent glutamate excitotoxicity, a primary mechanism responsible for MN loss in ALS animal models and in the human disease. Given these observations of GLT1 dysfunction in areas of MN loss, as well as the importance of testing therapeutic strategies for preserving PhMNs in ALS, we evaluated intraspinal delivery of an adeno-associated virus type 8 (AAV8)-Gfa2 vector to the cervical spinal cord ventral horn of SOD1(G93A) ALS mice for focally restoring intraspinal GLT1 expression. AAV8 was specifically injected into the ventral horn bilaterally throughout the cervical enlargement at 110days of age, a clinically-relevant time point coinciding with phenotypic/symptomatic disease onset. Intraspinal delivery of AAV8-Gfa2-GLT1 resulted in robust transduction primarily of GFAP(+) astrocytes that persisted until disease endstage, as well as a 2-3-fold increase in total intraspinal GLT1 protein expression in the ventral horn. Despite this robust level of astrocyte transduction and GLT1 elevation, GLT1 overexpression did not protect PhMNs, preserve histological PhMN innervation of the diaphragm NMJ, or prevent decline in diaphragmatic respiratory function as assessed by phrenic nerve-diaphragm compound muscle action potential (CMAP) recordings compared to control AAV8-Gfa2-eGFP injected mice. In addition, AAV-Gfa2-GLT1 did not delay forelimb disease onset, extend disease duration (i.e. time from either forelimb or hindlimb disease onsets to endstage) or prolong overall animal survival. These findings suggest that focal restoration of GLT1 expression in astrocytes of the cervical spinal cord using AAV delivery is not an effective therapy for ALS.

Biomechanical characteristics of the porcine denticulate ligament in different vertebral levels of the cervical spine-preliminary results of an experimental study

BACKGROUND

Few studies exist on the mechanical properties of denticulate ligaments and none report the variation in these properties at different levels of the spine. The aim of this study was to perform an experimental determination of load-extension and stress-strain characteristics of the denticulate ligament and to establish if their properties change at different vertebral levels of the cervical spine.

METHOD

The study was carried out on a total of 98 porcine denticulate ligament samples dissected from seven fresh porcine cervical spinal cord specimens. All of the samples were subjected to an uniaxial tensile test at a speed of 2mm/min, during which the load-extension characteristics were registered.

RESULTS

The analysis revealed a decrease of the failure force in the caudal orientation indicated by significant differences between the C1 (1.04±0.41N) and C7 (0.55±0.12N) vertebral levels (P=0.037). The average ultimate force that broke the denticulate ligaments was 0.88N. The mean value of Young׳s modulus was 2.06MPa with a minimum of 1.31MPa for C7 and maximum of 2.46MPa for C5.

CONCLUSIONS

The values of the denticulate ligament failure force in samples from different cervical vertebrae levels differ significantly. The presented data should be taken into consideration during numerical modelling of the human cervical spinal cord.

Complete cervical spinal cord injury above C6 predicts the need for tracheostomy

BACKGROUND

Failed extubation and delayed tracheostomy contribute to poor outcomes in patients with a traumatic spinal cord injury (SCI). We determined if the level and completeness of SCI predict the need for tracheostomy.

METHODS

Data from 256 patients with SCI between C1 and T3 with or without tracheostomy were retrospectively analyzed. Logistic regression identified predictors for tracheostomy. Data are presented as raw percentage or odds ratio (OR) with 95% confidence interval. P < .05 indicates significance.

RESULTS

Complete spinal cord injuries were common in patients requiring tracheostomy (55% vs 18%, P < .05), and predicted the need for tracheostomy (OR: 6.4 (3.1 to 13.5), P < .05). An injury above C6 predicted the need for tracheostomy in patients with complete injury (OR: 3.7 (1 to 11.9), P < .05), but not incomplete injury (OR: .7 (.3 to 1.9); P = .53).

CONCLUSION

Tracheostomy is unlikely in patients with incomplete SCI, regardless of the level of injury. Patients with complete SCI above C6 are likely to require tracheostomy.