短节段椎弓根螺钉置入内固定椎体成形治疗胸腰椎骨折的生物力学检测☆

背景：为避免单纯椎弓根螺钉置入内固定治疗胸腰段骨折出现的内固定物松动、断裂,及合并植骨时出现的骨折不愈合、后凸畸形丢失,而发展的短节段椎弓根螺钉合并椎体成形技术治疗胸腰段骨折,临床已有应用,但其生物力学方面鲜有研究。 目的：观察应用椎弓根螺钉置入内固定椎体成形治疗胸腰椎骨折的生物力学变化。 方法：12个冻存的新鲜胸腰段脊椎(T12~L2)标本,用于制备胸腰椎骨折模型,备测试。分为3组,经皮椎体成形术组：给予经单侧椎弓根注入低黏度的含对比剂骨水泥5~7 mL;椎弓根螺钉内固定组：于T12、L2椎弓根置入螺钉;强化组：行椎弓根螺钉内固定的同时行伤椎骨水泥椎体成形术,测试各组静态最大抗压强度及刚度。 结果与结论：骨水泥分布面积皆大于50%,经皮椎体成形术组和椎弓根螺钉内固定组最大静态抗压强度与刚度均小于强化组最大强度和刚度(P < 0.05)。椎弓根螺钉内固定组椎弓根螺钉较小强度下出现弯曲,而强化组在达到极性轴向压缩强度时才出现弯曲。提示应用短节段椎弓根钉置入内固定椎体成形治疗胸腰椎骨折提高了固定的强度及刚度,并且维持了复位伤椎高度,提高了稳定性,减少了椎弓根螺钉的并发症。     

伤椎椎弓根置钉治疗胸腰椎压缩性骨折的三维有限元分析*

背景：有文献报道伤椎置钉技术较传统4钉跨阶段固定具有更强的牢固性,可有效避免内固定的松动断裂,但其生物力学机制研究尚显不足。 目的：构建脊柱胸腰椎单纯压缩性骨折的三维有限元模型,探讨伤椎附加椎弓根螺钉置入治疗胸腰椎压缩性骨折的生物力学效应。 方法：将一T12椎体压缩性骨折患者脊柱胸腰段超薄CT扫描数据输入Mimics软件中,构建T12椎体压缩性骨折的有限元模型,在此模型基础上模拟伤椎置6钉和跨节段4钉内固定,对两个模型分别施加垂直压缩、前屈、后伸、左屈及右旋载荷。 结果与结论：两组固定模式各种载荷下的应力均集中在螺钉根部,在垂直载荷下,螺钉的应力最小,右旋和左屈载荷下的应力最大;在垂直压缩、前屈、后伸、左侧弯及右旋运动下,上位螺钉较下位螺钉应力大(P < 0.05)。伤椎置6钉固定组螺钉应力较跨节段4钉固定组小(P < 0.05)。两组T11椎体最大位移无差别。表明伤椎附加椎弓根螺钉置入可以优化内固定的载荷,减少断钉率。     

无神经症状单节段胸腰椎爆裂型骨折行后路短节段椎弓根螺钉内固定置入186例

背景：胸腰椎骨折治疗方法众多,但是对于无神经症状的爆裂型骨折,采用简单的手术方法治疗,是否在减少创伤的同时能够取得较好的疗效,从而避免手术的扩大化尚不清楚。 目的：观察采用单纯后路短节段椎弓根螺钉系统置入治疗无神经症状的单节段胸腰椎爆裂型骨折的疗效。 方法：选择2003-09/2008-01苏州大学附属第一医院骨科收治的无神经症状单节段胸腰椎爆裂型骨折患者186例,男152例,女34例,年龄18~65岁。均采用单纯后路短节段椎弓根螺钉内固定置入治疗,椎管内骨块占位采用间接复位。于置入前、置入后及置入后1年余取内固定前摄以伤椎为中心的X射线正侧位片和CT,对X射线平片和CT进行测量,统计伤椎前缘高度、伤椎横截面积内骨块的占有率。 结果与结论：伤椎前缘置入前高度平均为正常的42%,术后为98%,内固定取出术前伤椎前缘高度为正常高度的98%。伤椎横截面积内骨块占有率,术前平均为34%,术后平均为13%,内固定取出术前为8%。提示应用后路短节段椎弓根螺钉系统治疗无神经症状的胸腰椎爆裂型骨折,能够提供脊柱足够的稳定性,有效恢复椎体高度、生理弧度和椎管容积。     

伤椎后路椎弓根螺钉置入并椎体内植骨重建胸腰椎椎体的高度

背景：后路短节段经椎弓根内固定器械可使骨折达到近似解剖复位效果,明显提高疗效,但远期随访矫形度数丢失、内固定失败等并发症较普遍。 目的：探讨经伤椎椎弓根螺钉置入固定结合经椎弓根植骨治疗胸腰椎骨折的可行性。 方法：对73例胸腰椎骨折应用椎弓根钉棒系统后路伤椎一侧椎弓根螺钉置入内固定,对侧经椎弓根通道采用自体骨和同种异体骨行椎体内植骨。 结果与结论：73例随访6个月内均获骨性愈合,脊柱植骨融合率100%,无螺钉松动、折断。1例Frankel分级C级无变化,1例D级无变化,其余患者神经功能及腰背痛明显改善;置入后6个月损伤节段后凸平均Cobb角、伤椎椎体前缘高度、椎管前后径残留程度均较治疗前明显恢复。表明经伤椎椎弓根钉置入内固定结合经椎弓根植骨治疗骨折可获得满意复位,重建椎体高度,增强脊柱的抗压稳定性,减少内固定因应力过大造成的断钉、矫正丢失等并发症。     

1000/胸腰段单节段骨折经椎弓根植骨结合短节段固定临床疗效评价

目 的 评价胸腰段单节段骨折经椎弓根植骨结合不同节段固定的临床治疗效果。方 法 自2005.1～2009.1年,资料完整并得到随访患者14例。所有患者骨折位置在T11～L2之间,椎体A型骨折,没有严重神经功能障碍。所有患者按照年龄分为A、B两组,A组：青壮年,平均年龄30.5岁（18～50岁）,7例,随访时间平均13.7个月（10～26个月）;B组：高龄组,平均年龄为65.9岁（51～79岁）,7例,随访时间平均14.4个月（11～24个月）。采用胸腰段后路经过椎弓根植骨及椎弓根螺钉系统内固定治疗,按照固定范围分为长节段固定和短节段固定。比较A、B两组患者手术时间、出血量、并发症及手术前,术后1周内,术后1年后骨折椎体高度及骨折节段后凸角度变化。结 果 所有患者术后脊柱后凸角度均得到明显矫正,骨折椎体高度得到明显恢复。随访1年后,A、B两组采用短节段固定者均发生一定程度的矫正角度丢失,但两组之间没有明显统计学差异。在A组虽然长、短节段固定组之间存在不同程度的矫正角度丢失,但无统计学差异;在B组采用长、短节段固定之间存在显著差异,P＜0.05。结 论 青壮年单节段胸腰段骨折患者后路经椎弓根植骨结合短节段固定临床疗效满意;高龄患者选择经椎弓根植骨结合长节段固定疗效更为理想。     

椎弓根螺钉和椎板钩选择性融合治疗胸椎青少年特发性脊柱侧弯的差异

背景：既往的文献多报道用椎板钩或联合椎弓根螺钉治疗特发性脊柱侧弯或讨论融合节段的选择。 目的：比较椎弓根螺钉和椎板钩治疗青少年特发性脊柱侧弯临床疗效的差异，并行影像学评价。 方法：选择66例连续观察的青少年特发性脊柱侧弯(胸段主弯、腰段代偿弯)患者，均行后路内固定融合，末端融合到T12或L1椎体。其中32例行椎板钩内固定，34例行椎弓根螺钉内固定，内固定后最少随访2年。 结果与结论：椎弓根螺钉组患者内固定后胸段Cobb角矫正程度及腰段Cobb角自发矫正程度明显大于椎板钩组(P < 0.001)。椎板钩组内固定后13例患者冠状面朝左侧失代偿大于20 mm(参照C7铅垂线)，而椎弓根内固定组仅4例，差异有显著性意义(P < 0.005)。两组患者均无并发症发生。提示后路选择性融合治疗特发性脊柱侧弯(胸段主弯、腰段代偿弯)，与椎板钩相比，椎弓根螺钉有更好的矫正效果且内固定后冠状面失代偿发生率低。     

短节段椎弓根钉内固定治疗胸腰段脊柱骨折脱位临床分析

目的探讨短节段椎弓根钉内固定治疗胸腰段脊柱骨折脱位的临床疗效。方法我院诊治30例胸腰段脊柱骨折脱位患者短节段椎弓根钉内固定治疗。分别于术前、术后2周和6个月X线正侧位片检查,观察患者椎体复位、植骨融合以是否发生椎弓根钉松动、断裂等情况。结果术后2周和6个月伤椎椎体前缘高度与术前相比（53.1%）均明显升高（97.9%和95.3%）,差异均有统计学意义（P〈0.05）;术后2周和6个月Cobbs角与术前相比（25.3°）均明显降低（4.7°和5.0°）,差异均有统计学意义（P〈0.05）。手术过程中未出现严重并发症。结论对于胸腰段脊柱骨折脱位患者,短节段椎弓根钉内固定是一种有效的手术方法,能够明显提高临床疗效,且并发症少,值得临床推广应用。     

E经后路椎弓根钉固定结合硫酸钙椎体成形术治疗胸腰椎压缩性骨折的生物力学研究

背景：经后路复位椎弓根螺钉固定治疗胸腰椎压缩性骨折,常遗留脊柱前柱骨质缺损,其结果可导致术后内固定的松动、断裂及椎体高度的丢失。为避免此类并发症的发生,骨折椎体的强化必须的。目前临床应用硫酸钙骨水泥进行椎体成形术是一新的治疗方法,有必要对其治疗中的生物力学特性进行研究。 目的：探讨经后路椎弓根螺钉固定结合硫酸钙椎体成形术治疗胸腰椎压缩性骨折的生物力学性能。 设计、时间及地点：随机对照研究,2009年3月在上海大学生物力学研究所进行实验。 材料：15具新鲜小牛脊柱标本,分割成功能节段T11-L1,剔除肋骨及附着的肌肉组织,保留椎间韧带及关节突完整。脊柱穿刺针（美国Wright公司）,针芯直径3.2mm,其尾部可与配套注射器连接;硫酸钙骨充填物为美国Wright医疗器械公司的MIIG-X3系列;万能材料试验机及其他必要的测量仪器由上海大学生物力学研究所提供。 方法： 15具新鲜小牛T11-L1脊柱功能单位（Function spine unit FSU）,随机分3组：正常完整标本组（A组）,后路复位椎弓根钉固定组（B组）,后路复位椎弓根钉固定结合硫酸钙椎体成形组（C组）。B、C组标本制成T12椎体屈曲压缩性骨折模型,分别采用后路复位椎弓根钉固定及后路复位椎弓根钉固定结合硫酸钙椎体成形。3组标本在WE-10型万能材料试验机进行生物力学测试。收集实验数据进行统计学处理,进行组间比较。 主要观察指标：加载不同级别载荷,在轴向压缩、屈曲、伸展、侧屈4重工况下检测FSU的载荷-应变关系、载荷-位移关系、强度、刚度及抗扭等生物力学性能,收集实验数据。 结果： 胸腰椎载荷-应变及载荷-位移关系呈线性变化,C组的椎体和椎间盘平均应变比B组低14%和12%,比A组的低21%和13%;3组标本位移比较,C组位移分别比B、A组减少25%和37%。胸腰椎FSU的椎体和椎间盘的强度,C组比B组高14%和24%,比A组高13%和20%;胸腰椎刚度,C组比B、A分别高44%和53%。胸腰椎FSU最大抗扭强度,C组分别比B、A组高18%和30%,扭转刚度C组分别比B、A组高30%和40%。以上数据经统计学处理,差异均具有统计学意义（P＜0.05）。 结论：经后路椎弓根螺钉固定结合硫酸钙椎体成形术治疗胸腰椎压缩性骨折的生物力学性能是优越的,不但强度、刚度大,而且术后的胸腰椎体稳定,有利于减轻内植物的应力负荷,进而降低螺钉的松动、折断发生率及术后椎体高度的丢失。     

后路及单侧椎间孔和前路腰椎椎体间融合并置入椎弓根螺钉后相邻节段的生物力学变化

目的：比较经后路、单侧椎间孔、前路腰椎椎体间融合及附加椎弓根螺钉后相邻节段的力学性能。 方法：新鲜的雄性小牛L1~L5节段脊柱标本15具。随机取5只标本作为正常对照组,在非破坏状况下测试其力学指标后,再将15只标本随机分为3组,按要求制作L4/5前路椭圆形碳纤维Cage 1枚融合（前路腰椎椎体间融合组）、后路长方体碳纤维椎间Cage 2枚融合（后路腰椎椎体间融合组）和侧方椎间钛合金Cage 1枚融合（单侧椎间孔腰椎椎体间融合组）模型。测试完成后,每个标本附加L4/5节段双侧Moss-miamiTM椎弓根螺钉测试。 结果：3种融合方法在附加内固定前后应变和位移都高于正常对照组,强度低于正常对照组（P<0.01）,3组间以单侧椎间孔腰椎椎体间融合组变化最大,后路腰椎椎体间融合组最小（P<0.05）;在内固定前后配对比较,附加内固定后各组应变、位移增加,强度降低（P<0.05）。 结论：3种融合方法在附加内固定前后都有加速上位相邻节段退变的趋势,附加内固定比单纯融合更易导致相邻节段退变,单侧椎间孔腰椎椎体间融合退变趋势更加明显,后路腰椎椎体间融合的趋势相对较小。     

不同治疗方案对胸腰椎体骨折疗效和神经损伤的影响

目的探讨不同治疗方案对胸腰椎体骨折疗效和神经损伤的影响。方法 50例胸腰椎体骨折根据治疗方式不同分为观察组和对照组。对照组接受传统的剥离伤椎椎旁肌肉治疗方式,观察组接受后路椎弓根Schanz螺钉内固定术部分剥离伤椎椎旁肌肉的治疗方式。对比2组手术时间、术中出血量、术后出血量、术前和术后1周疼痛视觉模拟量表评分(VAS)、椎体高度矫正率以及后凸Cobb角矫正率。结果观察组术中出血量和术后出血量明显低于对照组,手术时间明显短于对照组,差异均有统计学意义(P0.05);2组椎体高度矫正率及后凸Cobb角矫正率差异均无统计学意义(P0.05);观察组术后1周后VAS评分明显低于对照组,差异有统计学意义(P0.05)。结论与传统后路手术方法相比,后路椎弓根Schanz螺钉内固定术部分剥离伤椎椎旁肌肉治疗胸腰椎骨折出血量少,手术时间短,疼痛程度低,恢复快,对神经损伤修复好,值得临床推广。     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.     

Summary of Legislation of 1933 of interest to the Department of Mental Hygiene

Psychiatric Quarterly -