椎板切除对颈脊髓前部受压减压效果的生物力学探讨

目的；观察椎板切除对颈脊髓前部受压的减压效果。方法：采用新鲜成年尸体的完整脊柱７具，将小型压力传感器置入椎管，对颈脊膜脊髓由前向后致压，致压深度分别为椎管矢状径的２０％、３０％和４０％，记录颈椎椎板切除前后不同致压深度下脊膜脊髓受压压力的变化以及硬膜囊的位移。结果：传感器致压深度达到椎管矢状径的４０％，脊膜脊髓的前部受压压力３．８６ｋＰａ，硬后壁上测得的压力为０．３８ｋＰａ；椎板切除后颈脊膜脊髓受     

颈脊髓损伤MRI的诊断分型(附66例手术所见分析)

本文报告66例急性颈髓损伤,通过MRI检查,有三种压迫颈髓情况:1.单纯椎间盘突出,2.椎间盘与骨折块一起压迫颈髓;3.单独骨折块压迫颈髓。在脊髓成像上显示的病理变化;1.硬脊膜与脊髓水肿,在T_2—wis上为明亮的高信号成像;2.脊髓信号呈暗淡的低信号成像;3.脊髓信号变化的脊段没有脊髓受压现象。在治疗上:单纯椎间盘突出患者效果比较满意,椎间盘与骨折块同时压迫者或单独骨折块压迫者效果比较差;脊髓信号变化与受压平面不一致者,可给予保守治疗,必要时,手术能获得满意效果。     

颈脊髓后方致压三维运动下生物力学分析

目的研究颈黄韧带病变对颈脊髓后方致压,颈脊髓所受压力与致压深度、颈脊柱三维运动的关系,为探讨黄韧带病变所致颈脊髓病的发病机制提供运动学、生物力学依据。方法采用5具新鲜成人尸体颈脊柱标本(C2～C7)通过后方C4～5间骨窗伸入直径9．58 mm的半球形致压物模拟颈椎黄韧带病变时对颈脊髓后方所形成的压迫。实验对颈脊髓由后向前致压,致压深度分别为椎管中矢径的10％～60％、依次增加10％。分别测量各运动位置,不同致压深度下,颈脊膜脊髓后方所受压力。结果 (1)随致压深度的增加颈脊髓脊膜后方所受压力明显加大,两者呈非线性关系。(2)颈脊髓后方致压时,测得颈脊髓脊膜后方所受压力,在前屈后伸运动中,20％～60％各相邻致压深度两两比较,差异有统计学意义(P<0．05);在中立位、左右侧弯、左右旋转运动中运动中 30％～60％各相邻致压深度两两比较,差异有统计学意义(P<0．05);(3)左右侧弯、左右旋转时, 相同致压深度,两侧侧弯、旋转各自比较差异无统计学意义(P>0．05)。予以合并取均数分别命名为侧弯30°位、旋转15°位。(4)在各运动位置,不同致压深度颈脊髓脊膜后方所受压力变化比较, 30％～60％致压深度时,前屈30°位>侧弯30°位>后伸30°位>中立位>旋转15°位。10％～20％致压深度时,侧弯30°位>后伸30°位>前屈30°中立位>旋转15°位。结论颈脊髓后方所受压力与致压深度和颈脊柱运动有着密切联系。所受压力随致压深度增加而增大,深度超出30％临界值后有统计学意义。相同致压深度颈脊髓后方所受压力大小随运动方向不同而改变,前屈后伸运动对颈脊髓的压力影响最大。     

脊髓的生物力学特性及测量的研究进展

脊髓是由灰质和白质构成, 被硬脊膜、蛛网膜、软脊膜、齿状韧带和脑脊液所环绕。脊髓及其周围不同解剖结构的生物力学特性相关研究已证实脊髓属于非线性黏弹性介质, 灰质和白质均具有超弹性材料的特性, 在单轴拉伸和机械压缩实验方面的力学性能各异。人体脊髓在全长上呈粗细不均匀的状态, 而各节段的硬脊膜表现出明显的异向性, 其弹性模量自颈髓至腰髓逐渐减小。尽管对蛛网膜生物力学行为的研究较少, 但其对提升脊柱有限元模型的预测准确性具有非常大的潜力。关于人软脊膜生物力学行为的研究尚无文献报道。脊髓浸润在脑脊液中, 脑脊液可作为脊髓的震动缓冲器, 因此在讨论脊髓的生物力学行为时不应忽视脑脊液的重要作用。当脑脊液压力升高时, 脊髓的应力也会升高, 反之亦然。齿状韧带的强度自上至下逐渐减弱。脊髓组织柔软, 在受损时常发生拉伸、压缩和扭转等混合力学变化。脊髓的测量方法包括磁共振弹性成像(magnetic resonance elastography, MRE)、原子力显微镜、微压痕技术和脊髓造影等。MRE在脊髓形态学研究方面具有一定的优势。脊髓变形损伤时准确测量其力学参数难度大, 通过应用影像学技术显示脊髓的动...     

颈椎后路联合硬脊膜切开治疗严重颈脊髓损伤

目的 探讨严重颈脊髓损伤行后路加硬脊膜减压的治疗效果.方法 对16例严重颈脊髓损伤采用后路椎板切除、侧块钉-棒系统内固定的同时行硬脊膜减压.结果 本组获6～36个月的随访.完全性损伤及不完全损伤患者肌力、感觉均恢复明显.结论 严重的颈脊髓损伤患者,后路行硬脊膜切开能提供广泛有效的减压.不完全性损伤的恢复效果优于完全损伤者.     

脊髓造影加CT与MRI对颈椎病及后纵韧带骨化诊断价值的比较

本文通过对３８例脊髓型颈椎病术前脊髓造影加ＣＴ和ＭＲＩ结果的比较分析，就此二种检查方法的诊断价值做出了评价。结果提示在显示颈椎间盘突出方面，ＭＲＩ明显优于脊髓造影加ＣＴ；在显示颈椎骨质增生、ＯＰＬＬ、颈神经很受压方面，ＭＲＩ不如脊髓造影加ＣＴ；在显示颈椎管狭窄蛛网膜下腔和脊髓受压方面，ＭＲＩ和脊髓造影加ＣＴ无明显差异。     

神经肌肉兴奋性测定对颈椎病诊断及康复价值的探讨

神经肌肉兴奋性测定对颈椎病诊断及康复价值的探讨黄国志，梁东辉，向群，米改荣颈椎病是在颈椎间盘退行性改变的基础上，受应力作用，椎体及附件的骨质增生，韧带、关节囊等软组织退行性变，引起颈神经根、颈段脊髓、椎动脉、颈交感神经受刺激或／和受压的继发性改变，出...     

腰骶部脊髓脊膜膨出症两种术式的疗效分析

目的 分析腰骶部脊髓脊膜膨出症两种术式与近期疗效之间的关系。方法 回顾性分析1989年2月-2003年6月期间，采用两种术式治疗的腰骶部脊髓脊膜膨出症患儿38例，年龄范围介于7d-4月。其中2例伴有大小便失禁和双下肢弛缓性瘫痪。术前均摄取腰骶椎X线片，23例曾做了MRI检查，21例表现为脊髓圆锥低位或膨出于囊内。手术方法为单纯脊膜修补术18例和椎管扩大探查、脊髓拴系松解、脊膜修补术20例。对大小便失禁者分别采用Kelly评分法及Bruskewize评分法。结果 38例患儿术后平均随访3年，原有大小便失禁和双下肢弛缓性瘫痪的2例患者无明显恢复。单纯脊膜修补手术者，术后4例发生脊髓拴系综合征(Tethered cord syndrome，TCS)，Mill显示脊髓圆锥在原位粘连。椎管扩大探查、脊髓拴系松解、脊膜修补术后未发生TCS病例。结论 治疗腰骶部脊髓脊膜膨出，推荐选择椎管扩大探查、脊髓拴系松解、脊膜修补术。单纯脊膜修补术术后极易导致TCS的发生。     

病程5年以上平山病的临床与颈椎磁共振影像特点

目的研究病程5年以上平山病的临床与颈椎磁共振影像特点。方法对病程5年以上平山病16例和病程小于5年的平山病20例,行颈椎中立位及屈曲位磁共振扫描,观察颈段硬膜囊和脊髓的动态变化,以20例健康志愿者作为对照。结果 10例发病超过5年的患者肌肉萎缩仍在缓慢进展,颈椎屈曲位MRI可见硬脊膜前移、脊髓压迫和硬膜外血管扩张等;6例肌肉萎缩进展不明显者,颈椎屈曲位MRI见脊髓受压不明显;20例健康志愿者脊髓无异常。结论平山病肌肉萎缩3~5年后,部分患者病情仍在发展;病程5年以上的患者,颈椎屈曲位MRI显示脊髓仍受压者,肌肉萎缩仍可进展,需给予积极治疗。     

一次性颈椎后路椎管扩大成形术加经硬脊膜入路髓核摘除术治疗脊髓钳夹型颈椎病

目的 探讨采用一次性颈椎后路单开门椎管成形术加经硬脊膜入路椎间盘髓核摘除术治疗脊髓钳夹型颈椎病的手术方法及观察其近期手术疗效.方法 本组6例脊髓钳夹型颈椎病患者术前均行X线片、CT和MRI检查确诊.手术方法均采用颈后路单开门椎管扩大成形术,然后在颈椎间盘突出相应的硬脊膜的位置上纵行切开硬脊膜,显露颈髓和上、下神经根及齿状韧带,切开纤维环取出髓核组织.结果 本组6例均获随访,按JOA评分标准平均提高3-6分,肌力平均提高2-3级,术前症状基本消失或缓解.术后予以X线片及MRI复查,无明显并发症,钳夹节段的颈髓均显示压迫解除.结论 一次性颈椎后路单开门椎管扩大成形术加经硬脊膜入路椎间盘髓核摘除术是治疗脊髓钳夹型颈椎病的一种可行有效的手术方法.它可避免多次手术的痛苦.     

The biomechanics of decompressive laminectomy

The biomechanical effect of laminectomy as a means of relieving compression of the spinal cord-meningeal complex by an anterior mass was studied in ten grossly normal human cadaver spines. The basic experimental set-up involved drilling a sagittal plane hole transversely across a vertebral body to provide direct access to the anterior aspect of the neural canal. After securing a probe and linearly variable differential transformer (LVDT) assembly at each site to be tested, the probe was gently pushed into the neural canal; contact force against the tip of the probe as well as the depth of probe penetration was measured and recorded. Laminectomy did not alter the resulting contact force/anterior penetration plots at the fifth cervical, seventh thoracic, 12th thoracic, or third lumbar vertebra. Using the probe/LVDT assembly to measure anterior dural displacement and a cantilever displacement device to measure posterior dural displacement after laminectomy at the 12th thoracic vertebra, the authors found that although the anterior dura underwent gross displacement as the probe was pushed into the neural canal, the posterior dura displaced to a minimal degree. The extent of the laminectomy was not a factor. The study did not demonstrate any possible mechanism by which laminectomy could reduce the pressure exerted on the dura and neural elements by an anterior mass in a spine with otherwise normal neural canal dimensions.     

A biomechanical study of thoracolumbar spine fractures with bone in the canal. Part III. Mechanical properties of the dura and its tethering ligaments

Experiments were performed to determine some mechanical properties of the spinal cord-meningeal (SCM) complex and its tethering elements with reference to factors contributing to contact pressure of an anterior mass on the SCM complex with spinal fracture and the development of some means to relieve the pressure. Measurements were made using a combined microload cell and displacement transducer that was passed posteriorly through a hole drilled in vertebra T12 through the interpedicular space and contacted the cord. Loss of nerve roots and anterior ligaments as dural tethers in the lumbar region permitted the SCM complex to fall out of the lordosis of the canal and fail to resist transverse loading. Head and neck flexion increased contact force for a given depth of penetration, particularly in the cervical region. This was consistent with measurements of strain along the dura that was greatest in the cervical region. The dura was found to be elastic, having a failure strain averaging 34% but was uniform in thickness, stiffness, and elastic modulus along its length. The study did not delineate any surgical manipulation other than removal of the anterior mass that would be beneficial when there is anterior compression of the spinal cord.     

A biomechanical study of thoracolumbar spinal fractures with bone in the canal. Part I. The effect of laminectomy

A simulation of thoracolumbar spinal fractures with bone in the canal was performed using fresh cadaver spines. In the study, a hole was drilled anterior to posterior in vertebral body T12 to accommodate a microload cell and displacement transducer that was then manually pushed into the canal to simulate the compressive effect of retropulsed bone on the spinal cord. In this part of the study, measurements were made pre- and postlaminectomy. The results indicated that laminectomy had no decompressive effect with up to 35% occlusion of the canal. Measurements of dural wall deflection during penetration of the load cell indicated that the anterior wall deformed locally due to penetration of the load cell with minimal displacement of the posterior wall occurring.     

腰椎狭窄软性椎管的应力改变分析

目的 探讨腰椎软性椎管改变与椎管狭窄的关系。方法 在本研究52例中分为椎管狭窄组和对照组，2003年1月至2007年12月，推管狭窄组从因腰椎管狭窄病行后路椎板减压术的患者中取黄韧带标本对照组黄韧带标本共为10例，取自青年腰椎骨折行后路椎板减压术患者，后纵韧带标本共4例取自腰椎爆裂骨折前路椎体减压术患者。分别观察两组标本切片镜下的表现并加以分析。结果 在腰椎管狭窄病组，黄韧带及后纵韧带镜下表现为纤维肥大，基质内可见脂肪及小囊肿；对照组则表现为纤维细胞排列规则、无纤维化表现。结论 腰椎管软性椎管的应力改变及退行性变，是导致腰椎管狭窄的一个因素。     

后路椎体间融合术防治下腰椎不稳

作者报告兼施后路椎体间融合术防治下腰椎不稳28例,除2例植骨块脱出再手术,均取得满意疗效。手术成功的关键有5:(1)下腰椎体间(L_4～S_1)手术;(2)植人骨柱比椎体间骨孔直径大1～2mm;(3)稍大坚质片嵌塞骨孔;(4)术后石膏制动;(5)手术面宽敞,采用椎板后移回植术显露。笔者认为本手术对腰椎间盘突出症摘除突出物后潜在的脊柱不稳是一种重要的防治措施。     

带蒂复合体回植成形术治疗腰椎管狭窄症

为避免椎板切除术后产生腰椎不稳和瘢痕粘连，作者采用带蒂复合体回植成形术治疗严重腰椎狭窄症３６例。方法是把椎板，棘突及其间的韧带作为复合体掀起显露椎管，复合体两侧植骨或劈开棘突后回植成形扩大椎管。随访８个月以上者３３例，优２７例，良５例，差１例。术后腰椎后部结构得到重建，有利于腰椎稳定和正常活动，避免术后硬脊膜外瘢痕粘连。     

Gunshot injury of the spinal cord

108 pigs were shot at the level of lumbar 1 to investigate the changes of spinal cord in relation to the speed of shooting and the trajectory through which the bullet passed. The cord lesions of the specimens could be divided, according to its severity, into 4 grades: (1) transection in 41; (2) complete destruction in 43; both lesion 1&2 resulted in permanent paraplegia; (3) incomplete destruction in 13, those resulted in incomplete paraplegia eventually recovered; (4) mild damage, that was concussion in 11, resumed perfectly. Through a transducer sealed into the spinal canal, the intracanal pressure was recorded: (1) Shooting through spinal canal with a pressure over 5 kg caused cord transection. (2) shooting through canal wall with a pressure of 2.5 to 5; 0 kg caused complete cord destruction. (3) shooting nearby the outer margin of vertebra with a pressure less than 1.0 kg caused mild cord damage. It was found that the speed of bullet, the trajectory with relation to cord and the grade of cord lesion are in agreement with each other. The mutual effects among them would make one think it reasonable to classify cord injury as follows: 1. Injury from bullet through spinal canal or vertebral body usually causes cord transaction; 2. Injury from bullet through canal wall at high speed would make a chance of complete destruction in 94%; at low speed, a chance of either complete or incomplete lesion in 50% each. 3. Injury nearby vertebra, high speed bullet would cause a chance of complete cord lesion in 86%; low speed one would make a chance of incomplete lesion in 1/3 and mild lesion in 2/3.     

胸腰椎爆裂骨折椎管内骨片侵入倾向与对策

根据98例中获得随访的39例的X线、CT和MRI(24例)影像学资料,分析胸腰椎爆裂骨折椎管内骨片侵入倾向及对策。将爆裂骨折侵入椎管分为四类八型,宜采用Harrington器械钢丝或椎弓根螺钉钢板轴向撑开系统,使骨折复位,椎管容积恢复,毋需行后路椎管减压。本组取得良好效果。仅对骨片游离型需要切开椎管直接摘除骨片。     

胸腰椎骨折椎管狭窄与神经功能的关系

对106例连续性胸腰椎爆裂骨折进行回顾性研究,探讨椎管狭窄与神经功能的关系。按自行设计的改良Frankel法将神经功能分六级,将椎管分脊髓圆锥段和马尾神经段,用直线回归相关法分析椎管狭窄与神经损伤程度之间的关系,用等级相关法分析椎管狭窄与发生神经损伤可能性之间的关系。结果表明:无论在脊髓圆锥段或马尾神经段,椎管狭窄与神经损伤程度、损伤可能性之间均存在相关性(r或r_s=0.38～0.90,P<0.05),且脊髓圆锥段的相关程度较高;相同程度椎骨狭窄致神经危害性在脊髓圆锥段较大。发生神经损伤的最小椎管狭窄在脊髓圆锥段为38％,在马尾神经段为63％(?)认为胸腰椎骨折椎管狭窄是神经损伤的主要因素,X-CT扫描可较好地预测神经损伤程度和损伤可能性。