经皮RTS钉固定与常规椎弓根固定在胸腰段压缩骨折中的疗效比较

目的:分析和比较使用经皮RTS钉固定与常规椎弓根固定在胸腰段骨折中的临床疗效和安全性。方法:对2017年6月至2018年6月在我院住院,经诊断为胸腰段骨折,且经纳入及排除标准筛选后的共计74例患者进行回顾性分析。根据不同的手术方式和选择,将纳入的患者分为经皮RTS钉固定组(观察组;40例)和常规椎弓根螺钉固定组(对照组;34例)。在术后的3天,1月及1年比较两组患者的疼痛评分及功能评分;并通过其影像学指标(伤椎高度恢复,cobb角恢复等)比较两组的影像学疗效;比较两组患者的手术时间,出血量,切口长度等手术指标;比较两组患者的并发症等情况。结果:在术后3天时,观察组患者的VAS评分显著优于对照组(P0.05),而在术后1月及1年时,两组患者未见显著差异(P0.05)。两组患者的Cobb角及前缘高度百分比较术前均有显著改善(P0.05),且两组间均有显著差异(P0.05)。两组患者在手术时间,切口长度,透视次数,出血量,出院时间等均有显著差异(P0.05)。两组患者在并发症的比较中并无统计学差异(P0.05)。结论:与常规的开放椎弓根螺钉固定相比,对于胸腰椎压缩骨折,RTS螺钉能够有效的恢复影像学指标,特别是在前缘高度及Cobb角恢复,并且能够有效地减少创伤及出血,加快功能恢复,在临床中可以进一步推广。     

骨质疏松性脊柱内固定技术进展

骨质疏松症是一种以骨量减少,骨强度下降而脆性增加,骨折风险增加为特征的骨骼疾病。随着人口老龄化日趋严重,骨质疏松症已成为我国面临的重要公共健康问题。这些患者往往并存多种疾病,其中椎体骨折最为突出,危害较大。由于此类患者的虚弱的体质和较低的骨密度,实施手术治疗十分困难。新型的手术方式的开发和内固定植入物的设计明显降低了内固定失败率,提升了内固定稳定性。这些技术综合考虑了生物材料学、生物学和生物力学等多方面,在临床应用上获得了较好的疗效。本综述旨在总结脊柱内固定失败的机制和现存的新型手术技术与内固定植入物设计,并对未来脊柱内固定手术的发展方向加以展望。     

脊柱椎弓根螺钉生物力学研究进展

椎弓根螺钉内固定术是目前临床上治疗脊柱骨折的常用手术方式。生物力学特别是脊柱生物力学方面的研究是其内固定器设计和研制的基础,也是评价其固定的稳定性及实用价值性的具体标准。因此,运用生物力学的理论知识来全面分析脊柱的力学改变及内固定器的作用机制,对于合理使用内固定器械以取得最满意矫形和固定效果具有重要意义。但现有实验条件及实验方法依然存在缺陷。例如,所有现有的实验均为体外实验,仅能反映即可实验结果,而且不能反映椎弓根螺钉在体内的长期力学特性。因此,本文通过椎弓根螺钉的自身设计、螺钉的植入技术、椎弓根螺钉的强化以及其他辅助椎弓根螺钉稳定性的辅助系统来全面分析脊柱椎弓根螺钉的生物力学。     

Biomechanical analysis of lumbar interbody fusion cages with various lordotic angles: a finite element study

Inappropriate lordotic angle of lumbar fusion cage could be associated with cage damage or subsidence. The biomechanical influence of cage lordotic angle on lumbar spine has not been fully investigated. Four surgical finite element models were constructed by inserting cages with various lordotic angles at L3-L4 disc space. The four motion modes were simulated. The range of motion (ROM) decreased with increased lordotic angle of cage in flexion, extension, and rotation, whereas it was not substantially changed in bending. The maximum stress in cage decreased with increased lordotic angle of cage in all motion modes. The maximum stress in endplate at surgical level increased with increased lordotic angle of cage in flexion and rotation, whereas it was not substantially changed in extension and bending. The facet joint force (FJF) was much smaller than that for the intact conditions in extension, bending, and rotation, while it was not substantially changed in flexion. In conclusion, the ROM, stresses in the cage and endplate at surgical level are sensitive to the lordotic angle of cage. The increased cage lordotic angle may provide better stability and reduce the risk of cage damage, whereas it may increase the risk of subsidence in flexion and rotation.     

腰椎管狭窄症脊椎融合术适应症研究进展

腰椎管狭窄症主要由腰椎关节强硬引起。腰椎狭窄症的临床表现分为两类:一类为局域性症状,如下腰痛,僵硬等,一类为神经根症状,如神经性跛行。适当保护性治疗可以改善这些症状,但是一些顽固病例仍需手术治疗。单纯腰椎管减压术适用于以神经根症状为初发表现并且脊椎生物力学稳定的患者。术前评估时如出现背部手术失败综合征,退行性不稳定,严重畸形,有症状的椎骨脱离,难治性退行性椎间盘疾病,以及邻近节段病的患者可行腰椎融合术。术中评估出现广泛椎体压缩合并椎间隙大或者骨储存量不足的患者可行腰椎融合术。     

An upper bound computational model for investigation of fusion effects on adjacent segment biomechanics of the lumbar spine

Abstract

Prediction of the biomechanical effects of fusion surgery on adjacent segments is a challenge in computational biomechanics of the spine. In this study, a two-segment L3-L4-L5 computational model was developed to simulate the effects of spinal fusion on adjacent segment biomechanical responses under a follower load condition. The interaction between the degenerative segment (L4-5) and the adjacent segment (L3-4) was simulated using an equivalent follower spring. The spring stiffness was calibrated using a rigid fusion of a completely degenerated disc model at the L4-5 level, resulting in an upper bound response at the adjacent (L3-4) segment. The obtained upper bound equivalent follower spring was used to simulate the upper bound biomechanical responses of fusion of the disc with different degeneration grades. It was predicted that as the disc degeneration grade at the degenerative segment decreased, the effect on the adjacent segment responses decreased accordingly after fusion. The data indicated that the upper bound computational model can be a useful computational tool for evaluation of the interaction between segments and for investigation of the biomechanical mechanisms of adjacent segment degeneration after fusion.     

Postural control of trunk during unstable sitting

A method for quantifying postural control of the lumbar spine during unstable sitting was developed. The unstable seat apparatus was equipped with leg and foot supports to isolate the control of the lumbar spine and trunk from the adjustments in the lower body joints. Polyester resin hemispheres with decreasing diameters were attached to the bottom of the seat to achieve increasing levels of task difficulty. The seat was placed on a force plate at the edge of a table and the participating subjects were instructed to maintain their balance while sitting on the seat. Coordinates of center of pressure (CoP) were recorded and quantified with summary statistics and random walk analysis. The CoP movement increased significantly with increased seat instability (task difficulty) (p<0.01). Stabilogram plots of the CoP movement revealed short and long-term regions consistent with the hypothesis that the two regions reflect open and closed-loop postural control mechanisms. Repeatability of the CoP parameters was excellent for the summary statistics and the short-term random walk coefficients (0.77<R<0.96). It was fair for the long-term diffusion coefficients (0.56<R<0.57) and poor for the long-term scaling exponents (0.14<R<0.40). Summary statistics of the CoP movement were positively correlated with body weight (0.69<R<0.73) and the T9 to L4/L5 distance (0.43<R<0.54) of the subjects. This method can be applied to study the deficits in postural control of the lumbar spine in low-back pain population.     

经皮与开放手术椎体椎弓根固定术治疗多椎体压缩性骨折的临床疗效比较

目的:研究和比较经皮椎体椎弓根固定术与开放手术治疗多椎体压缩性骨折的临床疗效及安全指标。方法:回顾性分析我科自2013.06至2015.06诊断为多椎体压缩性骨折并行内固定外科手术治疗的共计56例患者。根据手术方法的不同,分为实验组(经皮椎弓根固定组,32例)和对照组(开放手术固定组,24例)。对患者在术前即术后的各项临床指标进行随访和统计,对其VAS疼痛指标、JOA功能评分及患椎的前缘高度比进行比较。并比较两组患者的切口愈合,内固定松动等并发症。并比较两组患者的手术时间,出血量、下地时间等围手术期指标。结果:本次研究结果显示:经皮和开放椎体椎弓根固定术治疗的患者在术后及6月,12月的VAS及JOA评分中均获得了良好的改善,且两组之间并无统计学差异。在椎体前缘高度比值的比较中,术后开放组优于经皮固定组,但两者之间并无统计学差异。在并发症的比较中,经皮固定组显著优于开放手术组。在围手术期指标的比较中,经皮手术组在手术时间,出血量,下地时间等指标中都显著优于开放手术组。结论:对于多椎体压缩性骨折,经皮椎体椎弓根固定术能够达到与开放手术相似的临床治疗效果,但能够有效的减少并发症,并在手术时间,出血量,下地时间等指标中充分体现微创手术的优势。在多椎体骨折的治疗中可以进一步的进行推广。     

腰椎弹性固定进展研究

对于腰椎退变和不稳的治疗,传统方法是采用后路减压、椎弓根螺钉固定同时行植骨术(僵硬固定)。然而,僵硬固定存在加速周围椎体的退变等缺点。因而,人们逐步把目光投向腰椎弹性固定。最近几年,腰椎弹性固定因具有利于应力分散,防止周围节段退行性变,降低应力遮挡等优点,越来越多地被用于临床。大多数临床资料显示相较于传统坚强固定,弹性固定疗效相当,而固定节段骨萎缩、骨质疏松以及邻近节段退变的发生率显著降低,更利于脊柱生理特性。该文就腰椎弹性固定的发展过程、各种类型弹性固定的工作原理以及临床效果等作一综述。     

Activity of deep abdominal muscles increases during submaximal flexion and extension efforts but antagonist co-contraction remains unchanged

Lumbo-pelvic stability relies, amongst other factors, on co-contraction of the lumbo-pelvic muscles. However, during submaximal trunk flexion and extension efforts, co-contraction of antagonist muscles is limited. It was predicted that activity of the deeper lumbo-pelvic muscles that are often excluded from analysis (transversus abdominis (TrA) and the deep fascicles of multifidus (DM)), would increase with load in each direction. In eleven healthy subjects, electromyographic activity (EMG) was recorded from eight trunk muscles using surface and fine-wire electrodes. Subjects performed isometric flexion and extension efforts to submaximal loads of 50, 100, 150 and 200 N and a maximal voluntary contraction (MVC). Loading tasks were then repeated in trials in which subjects knew that the load would release at an unpredictable time. Compared to the starting position, EMG of all muscles, except DM, increased during MVC efforts in both directions. During the flexion and extension submaximal tasks, there was no increased co-contraction of antagonist muscles. However, TrA EMG increased in both directions. In the unpredictable trials, EMG of all lumbo-pelvic muscles except TrA was decreased. These findings provide further support for a contribution of TrA to lumbo-pelvic stability. In submaximal tasks, TrA activation may enhance stability as a strategy to improve trunk stiffness without requiring a concurrent increase in activity of the larger torque producing trunk muscles.     

经椎间孔腰椎融合术在腰椎翻修手术中应用的临床疗效

目的:探讨经椎间孔腰椎融合术(TLIF)在腰椎翻修手术中应用的临床疗效和安全性。方法:回顾性分析2008年10月至2012年5月38例腰椎术后需要翻修的患者接受TLIF手术治疗后的临床资料。结果:38例患者随访(22.6±4.4)个月;术前下肢疼痛和背部疼痛VAS评分分别为(8.2±1.6)分、(7.2±1.4)分,术后18个月下肢疼痛和背部疼痛VAS评分为(1.8±0.8)分,(1.5±0.7)分,术前和术后18个月相比较有统计学差异(P0.05)。功能障碍指数为24.3±8.2,较术前明显下降(P0.05),JOA评分为(25.5±7.6)分,较术前显著上升(P0.05);术后改善率和优良率均为86.8%;术前椎间高度和椎间移动幅度分别为(7.5±1.2)mm,(8.7±2.1)°,经TLIF技术治疗后相应指标依次为(10.6±1.9)mm,(1.8±0.7)°,差异显著(P0.05);骨融合率100%。结论:经椎间孔腰椎融合术(TLIF)治疗翻修的腰椎手术患者的临床疗效可靠,并发症少,值得推广。     

腰椎间融合器植入术治疗腰椎退行性疾病的临床疗效

目的:观察腰椎融合术结合腰椎间融合器植入对腰椎退行性疾病的治疗效果及对预后评估。方法:选择我院2013年1月至2014年1月收治的54例腰椎退行性疾病患者为研究对象,随机将其分为两组,对照组患者行单纯椎间植骨融合术,实验组患者给予腰椎融合术结合腰椎间融合器植入治疗,对两组患者的手术时间、手术失血量、住院天数、融合率及并发症情况进行观察,同时对术前、术后三个月均应用VAS评分、ODI评分评估患者恢复情况。结果:实验组融合率明显高于对照组,但实验组手术时间较对照组长,差异具有统计学意义(P0.05);两组术中出血量及住院天数无统计学意义(P0.05);与术前比较,两组患者VAS评分、ODI评分均明显降低,差异具有统计学意义(P0.05);与对照组比较,实验组术后VAS评分和ODI评分降低更明显,差异具有统计学意义(P0.05);疗效与并发症比较,实验组优于对照组(P0.05)。结论:腰椎融合术结合腰椎间融合器植入治疗腰椎退行性疾病临床疗效显著且安全性高,对患者预后较好。     

Pedicle screw-based posterior dynamic stabilisation of the lumbar spine: in vitro cadaver investigation and a finite element study

Pedicle screw-based dynamic constructs either benefit from a dynamic (flexible) interconnecting rod or a dynamic (hinged) screw. Both types of systems have been reported in the literature. However, reports where the dynamic system is composed of two dynamic components, i.e. a dynamic (hinged) screw and a dynamic rod, are sparse. In this study, the biomechanical characteristics of a novel pedicle screw-based dynamic stabilisation system were investigated and compared with equivalent rigid and semi-rigid systems using in vitro testing and finite element modelling analysis. All stabilisation systems restored stability after decompression. A significant decrease in the range of motion was observed for the rigid system in all loadings. In the semi-rigid construct the range of motion was significantly less than the intact in extension, lateral bending and axial rotation loadings. There were no significant differences in motion between the intact spine and the spine treated with the dynamic system (P>0.05). The peak stress in screws was decreased when the stabilisation construct was equipped with dynamic rod and/or dynamic screws.     

The role of trunk muscles in sitting balance control in people with low back pain

The purpose of this study was to examine the muscular activities and kinetics of the trunk during unstable sitting in healthy and LBP subjects. Thirty-one healthy subjects and twenty-three LBP subjects were recruited. They were sat on a custom-made chair mounted on a force plate. Each subject was asked to regain balance after the chair was tilted backward at 20°, and then released. The motions of the trunk and trunk muscle activity were examined. The internal muscle moment and power at the hip and lumbar spine joints were calculated using the force plate and motion data. No significant differences were found in muscle moment and power between healthy and LBP subjects (p > 0.05). The duration of contraction of various trunk muscles and co-contraction were significantly longer in the LBP subjects (p < 0.05) when compared to healthy subjects, and the reaction times of the muscles were also significantly reduced in LBP subjects (p < 0.05). LBP subjects altered their muscle strategies to maintain balance during unstable sitting, but these active mechanisms appear to be effective as trunk balance was not compromised and the internal moment pattern remained similar. The changes in muscle strategies may be the causes of LBP or the result of LBP with an attempt to protect the spine.     

Spinal stiffness in asymptomatic subjects

The objective of the study was to measure postero-anterior stiffness of thoracolumbar spine from normal asymptomatic subjects at T₄, T₉, and L₂ levels using a standardized device and protocol. Sixteen volunteer subjects (eight males and eight females) meeting the inclusion and exclusion criteria were recruited for the study. Their T₄, T₉, and L₂ spinous processes were identified and marked. These spinous processes were cyclically loaded with 22.5 N, 45 N, 90 N, and 135 N fixed forces at 0.1 Hz in postero-anterior direction by a computer controlled and operated Therapeutic Spinal Mobilizer (TSM) for five cycles to the level of subject’s acceptance of the load magnitude. The magnitude of the force and displacement experienced at the spinal level were recorded using a load cell and linear variable differential transducer. The stiffness was obtained from the slope of the load/deformation curve. The stiffness values were subjected to analysis of variance to determine the effect of independent variables. The stiffness at different levels was significantly different (p < 0.0001) and it was significantly affected by the testing load (p < 0.0001). The age, sex, height and weight were not significantly associated with the stiffness, neither were the cycles at the same load. The postero-anterior stiffness of the thoracolumbar spine is different at different spinal levels and varies with testing loads.