【作者】 张鹏；

【导师】 申勇；

【作者基本信息】 河北医科大学 ， 外科学， 2014， 博士

【摘要】 第一部分颈脊髓MRI高信号与神经细胞凋亡的相关性研究目的： MRI是目前公认的对慢性脊髓压迫性疾病最有价值的诊断方法之一，在临床实践中常可于患者MRI T2加权像发现局部或较广泛信号增强的区域，许多基础和临床工作者针对此MRI信号的改变，就MRI信号代表的临床症状和预后等问题进行了大量研究，但尚未得出统一的结论。特别对于MRI T2高信号的形成机制及其病理变化的相关实验研究较多，但是到目前仍存在着争议，现在越来越多的学者认为，神经细胞的凋亡在脊髓病变的发病机制中起着非常重要的作用，并对此进行了大量的研究。但是不同强度的颈脊髓MRI T2高信号与神经细胞凋亡之间是否存在着某种联系，目前针对此问题的相关研究比较少见，本研究通过慢性压迫性颈脊髓损伤动物模型的建立，观察并记录在慢性压迫状态下的颈脊髓MRI信号的变化，同时进行神经细胞凋亡的相关检测，从而探讨这两者之间的关系。方法：将实验用新西兰白兔32只，随机挑选8只做为对照组，余为实验组，实验组按文献要求建立兔脊髓型颈椎病动物模型。术后6个月将所有实验动物进行MRI检查并计算MRIT2与T1信号比值。MRI检测完毕后将所有实验动物处死并取受压迫脊髓部位行HE染色光镜观察；并行Bcl-2、Bax免疫组织化学染色，细胞内有棕黄色粗颗粒分布，或者棕黄色细腻颗粒弥漫分布者，记为阳性反应，以阳性细胞染色的平均光密度值来表示抗原表达量。结果：实验组可见MRI T2高信号的信号强度不等，T2/T1信号强度比值计算结果为2.52~12.03；对照组均未观察到明显高信号。随着MRI T2/T1信号比值增加，实验组细胞形态及Bax，Bcl-2表达量均发生不同程度的变化；Bax表达增多，胞质棕黄色程度加深；Bcl-2细胞棕黄色出现向核内转染；随着MRI T2/T1信号比值逐渐增大，Bax光密度值逐渐加大，Bcl-2光密度值逐渐减小。MRI信号比值与灰质及白质Bax表达量成正相关，与灰质及白质Bcl-2表达量成负相关。结论：本文通过量化脊髓MRI信号并取T2与T1加权像图像强度比值的方法分析了高信号与脊髓内的组织细胞凋亡之间的关系，结果显示随着脊髓内的组织细胞凋亡率会随着信号比值的增大而出现增高,相比与对照组，Bax因子的表达量增多，而Bcl-2的表达量却出现减少，颈脊髓MRI T2加权像上高信号可能与细胞的凋亡有一定的关系。第二部分MRI信号强度比值判断脊髓型颈椎病预后的意义目的：脊髓型颈椎病是一种常见的退行性疾病，是因颈椎间盘本身退变，及继发相邻骨与软组织退变，导致脊髓血供障碍或脊髓本身受压，从而引起的临床症候群，40岁-60岁人群中多见。脊髓型颈椎病临床表现多样，主要表现为四肢麻木、无力，走路不稳，有“踩棉花”感及胸腹部“束带”感，严重者可出现截瘫、大小便功能障碍，其进展快慢及转归因人而异，该病的诊断及治疗结果也因患者及医生对其的认识不同而不同。脊髓型颈椎病的影像学诊断方法包括颈椎X线片、CT、CT造影等，而MRI是目前公认的对脊髓型颈椎病最有价值的诊断方法，因为MRI不仅可以显示脊髓受压程度，而且可以显示脊髓内部变化的一些细节，检查结果常令人满意。另外，临床工作人员认为对于那些接受手术治疗的脊髓型颈椎病患者而言，术前MRI所显示的数据，比如脊髓受压迫的程度、椎管的横截面积以及脊髓内的信号变化，可能与术后患者的恢复情况相关联。近几年来针对MRI T2加权像高信号与患者预后的关系的研究较多，但是尚未形成统一观点，关于高信号的出现是否预示着患者在接受手术治疗后效果不佳目前尚有争议。本文在前期研究的基础上，进一步利用信号强度比值的方法探讨MRI T2加权像高信号与脊髓型颈椎病手术预后之间的关系。方法：2007年9月至2009年2月于我科行颈椎手术治疗脊髓型颈椎病患者52例，其中男30例，女22例；年龄45-67岁，平均56.3岁；病程3-34月，平均23个月；单节段受压23例，多节段受压29例；手术方式主要有颈椎前路椎间盘切除植骨融合内固定术、颈椎前路椎体次全切减压植骨融合内固定术、颈椎后路椎板切除减压术及颈椎后路椎管成形术；行颈椎前路手术治疗31例，行颈椎后路手术治疗19例。术前所有患者均行高分辨率1.5T MRI (Siemens, Berlin, Germany)。颈髓矢状面成像T1加权像采用自旋回波序列，T2加权像采用快速自旋回波序列。扫描使用颈椎线圈，层厚4mm，采集矩阵512×256。序列参数为T1加权像重复时间612ms，回波时间13ms。T2加权像重复时间2400ms，回波时间114ms。如果患者T2加权像存在信号强度增加的区域则测量此区域信号强度值，同时于T1加权像测量与T2加权像高信号区域处于相同节段的脊髓信号强度值，两者测量所取面积相近，操作均于MRI工作台上进行。T2加权像信号强度值与T1加权像信号强度值的比值为本文研究的T2/T1比值。无T2加权像高信号的患者归为组1，有T2加权像高信号的患者以T2/T1比值的中位数分为组2和组3。于术后第3、6、12、24个月对患者进行随访，每次随访均进行JOA评分，并与术前比较，计算改善率。结果：所有患者中，16例无T2加权像高信号(组1)；其他36例均有T2加权像高信号，T2/T1比值范围为1.18-2.77，其中位数为1.77，18例归为组2(T2/T1比值范围为1.18-1.74)，18例归为组3(T2/T1比值范围为1.79-2.77)。所有患者接受手术治疗后脊髓功能得到不同程度的改善，术前平均JOA评分为10.1，术后末次随访时平均JOA评分为12.4。无高信号的患者的术前JOA评分、术后JOA评分及改善率与有高信号的患者相比较，差异有统计学意义(P<0.05)，有高信号的患者的年龄、病程的平均数都相对较大(P<0.05)。经方差分析发现组1、组2和组3三组之间在术前JOA评分、术后JOA评分及脊髓功能改善率等指标间差异都有统计学意义(P<0.05)；进一步经Student-Newman-Keuls检验发现：术前JOA评分在组1、2之间，组1、3之间，组2、3之间差异也都有统计学意义(P<0.05)。术后JOA评分在组1、2之间，组1、3之间，组2、3之间差异有统计学意义(P<0.05)。改善率在组1、2之间，在组1、3之间，组2、3之间差异有统计学意义(P<0.05)。对36例有高信号的患者的资料进行多元线性回归分析，结果显示脊髓功能改善率与JOA评分及、程及T2/T1比值有线性回归关系(R2=-0.540，P<0.05)，并且与信号比值呈负相关。结论：本文通过对前期研究方法进行改良进一步探讨了脊髓型颈椎病患者T2加权像高信号与手术治疗效果的关系，通过分析发现有高信号的患者其术前病情较重，手术治疗效果较差，并且随着信号强度的增加，这一趋势更加明显。脊髓高信号可以做为判断脊髓型颈椎病预后的一项指标。第三部分MRI局灶性信号强度改变对单节段脊髓型颈椎病前路减压手术预后的意义目的：脊髓型颈椎病是一种常见的退行性疾病，是因颈椎间盘本身退变，及继发相邻骨与软组织退变，导致脊髓血供障碍或脊髓本身受压，从而引起的临床症候群，40岁-60岁人群中多见。脊髓型颈椎病临床表现多样，主要表现为四肢麻木、无力，走路不稳，有“踩棉花”感及胸腹部“束带”感，严重者可出现截瘫、大小便功能障碍，其进展快慢及转归因人而异，该病的诊断及治疗结果也因患者及医生对其的认识不同而不同，颈前路减压植骨融合内固定术是一种经典并且有效的术式，但是术后很多患者仍有症状，其效果被认为与术前多种因素相关，所以目前有大量研究专注于可用于预判手术长期效果的因素。MRI不仅可以显示脊髓受压程度，而且可以显示脊髓内部变化的一些细节，比如脊髓内的高信号可能代表脊髓长期受压引起的神经胶质瘤或脊髓软化。尽管现在许多文章在研究脊髓高信号与手术效果的关系，但是对于高信号与术后效果的影响目前尚有争议。一些作者报道术前脊髓高信号是术后效果较差的一个判断指标。但是也有一些作者认为髓内高信号与手术效果并无明显的联系。同时还有一些研究认为出现MRI T2局灶性高信号的脊髓型颈椎病患者在功能恢复方面和其他患者并无明显的差别。在这些研究中作者并没有提及脊髓受压节段以及手术节段是否与脊髓高信号所处节段相同。据我们所知，目前还没有关于局灶性信号强度改变对单节段脊髓型颈椎病前路减压预后的意义的结论性研究。本文的目的在于进一步探讨局灶性信号强度改变与单节段脊髓型颈椎病前路减压术后效果的关系。方法：2005年1月至2008年3月于我科行颈椎前路减压植骨融合内固定手术治疗的单节段脊髓型颈椎病患者59例，其中男36例，女23例；手术时年龄42-73岁，平均53.8岁；病程5-48月，平均21.3个月；所有患者均随访两年以上。术前所有患者均行高分辨率1.5T MRI (Siemens, Berlin, Germany)。颈髓矢状面成像T1加权像采用自旋回波序列，T2加权像采用快速自旋回波序列。扫描使用颈椎线圈，层厚4mm，采集矩阵512×256。序列参数为T1加权像重复时间612ms，回波时间13ms。T2加权像重复时间2400ms，回波时间114ms。测量所有患者T2加权像存在信号强度增加的区域的信号强度值，同时于T1加权像测量与T2加权像高信号区域处于相同节段的脊髓信号强度值，两者测量所取面积相近，操作均于MRI工作台上进行。T2加权像信号强度值与T1加权像信号强度值的比值为本文研究的T2/T1比值。根据系统聚类分析方法将所有患者分为3组。脊髓压迫率于MRI T2轴位像上测量。所有的数据由一位人员收集以及分析，所有的数据测量两次，取其平均值做为分析数据。于术后第3、6、12、24个月对患者进行随访，每次随访均进行JOA评分，并与术前比较，计算改善率。结果：所有患者的T2/T1比值范围为1.26-2.85，其中20例归为组1(T2/T1比值范围为1.28-1.63)，16例归为组2(T2/T1比值范围为1.7-2.18)，23例归为组3(T2/T1比值范围为2.25-2.85)。手术节段分布如下：C3-C4的患者15例，C4-C5的患者22例，C5-C6的患者13例，C6-C7的患者9例。椎体间以自体三皮质髂骨块进行融合的有21例，椎体间以填有自体碎骨的椎间融合器进行融合的有38例。所有患者接受手术治疗后脊髓功能得到不同程度的改善，术前平均JOA评分为9.6，术后末次随访时的平均JOA评分为12.7，末次随访时平均脊髓功能恢复率为45.7%。经方差分析发现组1、组2和组3三组之间在年龄、病程、术前JOA评分、术后JOA评分及脊髓功能改善率等指标间差异都有统计学意义(P<0.05)，但是三组间的脊髓压迫率差异无统计学意义（P=0.102）；进一步经Student-Newman-Keuls检验发现：年龄、病程、术前JOA评分及术后JOA评分在组1、2之间，组1、3之间，组2、3之间差异也都有统计学意义(P<0.05)。改善率在组1、3之间差异有统计学意义(P<0.05)，在组1、3之间，组2、3之间差异有统计学意义(P值分别为0.199，0.227)。对59例有高信号的患者的资料进行Spearman秩相关分析，结果显示T2/T1比值与年龄(rs=0.577，P<0.001)、病程(rs=0.652，P<0.001)、脊髓压迫率（rs=0.416，P=0.001）呈正相关，与术前JOA评分(rs=-0.759，P<0.001)、术后JOA评分(rs=-0.732，P<0.001)及脊髓功能改善率(rs=-0.564，P<0.001)呈负相关。逐步回归分析结果显示手术效果的变化与术前JOA评分及病程有线性回归关系。结论：本文通过对前期研究方法进行改良进一步探讨了单节段脊髓型颈椎病患者T2加权像高信号与手术治疗效果的关系，从结果来看，高信号预示着患者术前病情较重，手术治疗后改善较差，并且随着信号强度的增加这一趋势也较为明显对于接受单节段颈前路减压植骨融合内固定手术治疗的脊髓型颈椎病患者而言，术前局灶性MRI T2加权像高信号可以预判其手术效果。做为一项小样本回顾性研究，其结论需要多中心大样本前瞻性研究进一步证实。更多还原

【Abstract】 Part one Correlation between increased signal intensity on MRI of cervical spinal cord and nerve cell apoptosisObjective: To explore the correlation between different MRI T2signal change and nerve cell apoptosis in chronic cervical spinal cord compressive disease.Methods: Thirty-two New Zealand white rabbits were randomly divided into two groups: control group (n=8), experimental group (n=24). Experimental group was operated on to set up the animal model of cervical spondylotic myelopathy. Six months after surgery, MRI examinations were performed, in which signal intensity ratio was calculated. HE staining, and Bcl-2, Bax immunohistochemical staining of spinal cord specimens were studied in all animals.Results: Increased signal on MRI T2images were observed in the experimental group, and the signal intensity ratio ranged from2.52to12.03. Few Bax and Bcl-2positive cells were observed in control group; in experimental group, Bax expressions increased, and the brown color darkened in cell plasms, Bcl-2expressions increased in cell nucleus. The statistical results showed that the correspondent optical density of Bax became larger and optical density of Bcl-2became smaller in white matter and gray matter with the increasing of MRI signal intensity ratio.Conclusion: MRI T2increased signal intensity was significantly related to cell apoptosis in chronic cervical spinal cord compression. With the increasing of signal intensity ratio, there were more cell apoptosis, more Bax expression, and fewer Bcl-2expression. Part two Significance of Increased S ignal Intensity on MRI in Prognosisafter Surgical InterventionObjective: Cervical spondylotic myelopathy (CSM) is a common spinal disease, the main pathological mechanism of which was chronic spinal cord compression that resulted in spinal cord degeneration and a series of clinical syndromes, which often occurs in people aged40-60years. Some patients may have history of trauma. Spinal cord can be compressed ventrally by the nucleus pulposus, vertebral osteophytes, hypertrophic ligamentum flavum or dorsally by the ossified posterior longitudinal ligament, which mainly leads to numbness and weakness of limbs, unsteady gait, and paresthesia, even paraplegia, bowel and bladder dysfunction in some severe cases. Some of the patients with CSM need surgical treatment, and the outcone is associated with many preoperative factors. Recently, magnetic resonance imaging (MRI) of the cervical spine, which not only reveals anatomic spinal cord compression, but also reflects the pathologic changes in the spinal cord, has become extremely valuable for this diagnosis, usually with satisfactory results. In addition, some scholars believe that several predictive parameters obtained by MRI, such as the compression rate of the spinal cord, the transverse area of the spinal cord, and signal intensity change of the spinal cord, may be related to the post-operative recovery of patients who undergo surgical treatments for CSM. However, there is controversy over the predictive effect of these imaging parameters, especially in regards to the signal intensity change of the spinal cord on T2-weighted MRI: the increased signal intensity (ISI) of the spinal cord on T2-weighted MRI and the decreased signal intensity on T1-weighted MRI are considered to predict a poor outcome. The controversy arises partly because the intensity change has been assessed only qualitatively, but not quantitatively. Several authors concluded that patients with focal area of high intensity change on T2-weighted MRI would have the same functional recovery as those without high intensity change. However, the number of compressed and operated levels of spinal cord was not mentioned clearly for patients with focal ISI in thses reports. As far as we know, there has not yet conclusive reports that depicted the significance of focal signal intensity changes on T2-weighted MRI in patients with single-level CSM. The purpose of the present study was to determine whether signal intensity changes demonstrated on T2-weighted MRI can help to predict the prognosis after anterior cervical decompression and fusion for patients with single-level CSM by means of measuring the ratio of T2/T1signal intensity.Methods: Between January2005and March2008,59patients (36men and23women) who underwent anterior cervical decompression and fusion for single-level CSM were included. Their mean age was53.8years (range,42-73years) at the time of surgery, and the mean duration of disease was21.3months (range,5-48months). All the patients were followed up for a minimum of2years. All patients underwent high-resolution MRI with a1.5-Tesla Siemens MAGNETOM Symphony (Siemens, Berlin, Germany) imager before surgery. Sagittal T1-weighted and T2-weighted images of the cervical cord were obtained using a spin echo sequence system for T1-weighted MRI and a fast spin echo sequence system for T2-weighted MRI. A cervical coil was used. The slice width was4mm, and the acquisition matrix was512×256. The sequence parameters for T1-weighted images was a repetition time (TR) of612ms and an echo time (TE) of13ms; and for T2-weighted images, a TR of2400ms and a TE of114ms was used. For patients with an ISI on T2-weighted MRI, the T2:T1ratio at the same spinal cord level, and over an area roughly equivalent to the ISI area on T2-weighted MRI, was calculated by computer. Patients were divided into3groups by hierarchical clustering analysis according to T2/T1ratio. Compression rate was measured at the target level of the spinal cord on T2-weighted axial image. All of the data were collected and reviewed by an independent observer. Two-time measurements of the data were performed and the mean value was used for analysis. Neurological status was assessed according to the Japan Orthopaedic Association (JOA) score, before and after surgery; and recovery rate, which was calculated.Results: Overall postoperative clinical outcome revealed significant improvement. The mean preoperative JOA score was10.1and was12.4at the final follow-up visit. No patient required additional cervical decompressive surgery for recurrent or residual symptoms. Of the52patients, no ISI was detected on the T2WIs in16patients (group1). The36patients with ISI were older, had a longer duration of disease, a worse postoperative JOA score, and a worse postoperative recovery rate than those without ISI. The T2/T1ratios for patients with ISI on T2WI ranged from1.18to2.77. These patients were subdivided into two groups, split by the median T2/T1ratio (1.77): there were18in group2(T2/T1ratio range:1.18-1.74) and18in group3(T2/T1ratio range:1.79-2.77). The analysis of variance showed significant differences in the preoperative (P<0.001) and preoperative JOA scores (P<0.001) and the recovery rate (P<0.001) among three different groups. In addition, the Student-Newman-Keuls (SNK) test for the preoperative JOA score showed significant differences between groups1and2(P<0.05), groups1and3(P<0.05), and groups2and3(P<0.05). Significant differences for the final JOA score were noted between groups1and2(P<0.05), groups1and3(P<0.05), and groups2and3(P<0.05). When comparing the T2/T1ratio and recovery rates for the three different groups, significant differences were found between groups1and2(P<0.05), groups1and3(P<0.05), and groups2and3(P<0.05).Conclusion: Patients with ISI and higher T2/T1ratio tend to have relatively severe preoperative state of illness and poor prognosis after surgical intervention. Spinal cord signal intensity change on T2-weighted MRI might be a predictor of a poor outcome in terms of functional recovery rate in patients underwent operations for multi-level CSM.Part three Prognosis significance of focal signal intensity change on MRI after anterior decompression for single-level cervical spondylotic myelopathyObjective: Cervical spondylotic myelopathy (CSM) is a common spinal disease, the main pathological mechanism of which was chronic spinal cord compression that resulted in spinal cord degeneration and a series of clinical syndromes, which often occurs in people aged40-60years. Some patients may have history of trauma. Spinal cord can be compressed ventrally by the nucleus pulposus, vertebral osteophytes, hypertrophic ligamentum flavum or dorsally by the ossified posterior longitudinal ligament, which mainly leads to numbness and weakness of limbs, unsteady gait, and paresthesia, even paraplegia, bowel and bladder dysfunction in some severe cases. Some of the patients with CSM need surgical treatment, and the outcone is associated with many preoperative factors. Magnetic resonance imaging (MRI) can not only show the degree of compression of the spinal cord but also reflect the changes within the spinal cord in detail, for instance, increased signal intensity (ISI) might reflect myelomalacia or gliosis due to long-term compression of the spinal cord. The significance of ISI for prognosis remains controversial, though many studies had investigated the association between ISI and surgical outcome. Some authors reported that ISI is a predictor of poor prognosis after surgery. However, others found no correlation between surgical outcome and intramedullary ISI. Several authors concluded that patients with focal area of high intensity change on T2-weighted MRI would have the same functional recovery as those without high intensity change. However, the number of compressed and operated levels of spinal cord was not mentioned clearly for patients with focal ISI in thses reports. As far as we know, there has not yet conclusive reports that depicted the significance of focal signal intensity changes on T2-weighted MRI in patients with single-level CSM. The purpose of the present study was to determine whether signal intensity changes demonstrated on T2-weighted MRI can help to predict the prognosis after ACDF for patients with single-level CSM by means of measuring the ratio of T2/T1signal intensity.Methods: The participants in this study were59patients who underwent anterior cervical decompression and fusion for single-level CSM. There were36men and24women (mean age at the surgery,53.8years; range,42-73years). The symptom duration of these patients ranged from5to48months; with a mean symptom duration of21.3months. All patients underwent high-resolution MRI with a1.5-Tesla Siemens MAGNETOM Symphony (Siemens, Berlin, Germany) imager before surgery. Sagittal T1-weighted and T2-weighted images of the cervical cord were obtained using a spin echo sequence system for T1-weighted MRI and a fast spin echo sequence system for T2-weighted MRI. A cervical coil was used. The slice width was4mm, and the acquisition matrix was512×256. The sequence parameters for T1-weighted images was a repetition time (TR) of612ms and an echo time (TE) of13ms; and for T2-weighted images, a TR of2400ms and a TE of114ms was used. The T2:T1ratio at the same spinal cord level, and over an area roughly equivalent to the ISI area on T2-weighted MRI, was calculated by computer. Patients with ISI were subdivided into3groups by hierarchical clustering analysis according to T2/T1ratio. Neurological status was assessed according to the Japan Orthopaedic Association (JOA) score, before and after surgery; and recovery rate, which was calculated.Results: Anterior decompression was performed at C3-C415in patients, C4-C5in22patients, C5-C6in13patients and C6-C7in9patients. Fusion was achieved with tricortical iliac crest graft in21patients, titanium cage filled with bone in38patients. Overall postoperative clinical outcome showed significant improvement. The mean preoperative JOA score was9.6, and12.7at the final follow-up visit, it had improved to a mean score of3.1. The mean recovery rate was45.7%at the final follow-up visit. The range of T2/T1ratio of59patients was from1.26to2.85. Twenty patients were divided into group1(ratio range,1.26-1.67),16into group2(ratio range,1.7-2.18) and23into group3(ratio range,2.25-2.85). Analysis of variance showed significant difference in age at surgery (P<0.001), duration of disease (P<0.001), recovery rate (P=0.036), pre (P<0.001) and preoperative JOA score (P<0.001) among three different groups, but there was no significant difference in compression rate (P=0.102). Student-Newman-Keuls (SNK) test of age showed significant difference between groups1and2(P<0.05), groups1and3(P<0.05), and groups2and3(P<0.05). SNK test of duration of disease showed significant difference between groups1and2(P<0.05), groups1and3(P<0.05), and groups2and3(P<0.05). In addition, SNK test of pre and postoperative JOA score showed significant difference between groups1and3(P<0.05), groups1and3(P<0.05), and groups2and3(P<0.05). No significant difference in recovery rate was observed between groups1and2(P=0.199), and between Groups2and3(P=0.227), though there was significant difference between Groups1and3(P<0.05). Spearman’s rank correlation showed that T2/T1ratio was correlated with age at surgery (rs=0.577, P<0.001), duration of disease (rs=0.652, P<0.001), compression rate (rs=0.416, P=0.001), pre (rs=-0.759, P<0.001) and postoperative JOA score (rs=-0.732, P<0.001), and recovery rate (rs=-0.564, P<0.001). Stepwise regression analysis showed that the best combination of surgical outcome predictors included preoperative JOA score and duration of disease..Conclusion: Patients with higher T2/T1ratio tend to have relatively poor prognosis after surgical intervention. Focal spinal cord signal intensity change on T2-weighted MRI might be a predictor of a poor outcome in terms of functional recovery rate in patients underwent operations for single-level CSM.更多还原