胸腰椎椎弓根螺钉固定技术的研究进展

20世纪70年代Roy—camille首先应用椎弓根螺钉固定治疗胸腰椎骨折，30年来椎弓根螺钉固定技术发展迅速，已广泛应用于多种脊柱疾病的治疗。由于置入螺钉与周围组织，如脊髓、神经、血管等关系密切，存在一定风险和并发症，直到1999年美国FDA才正式批准该项技术为经典的脊柱后路固定方法之一。近些年在应用解剖、螺     

椎弓根劈裂对内固定稳定性影响的生物力学研究

目的探讨椎弓根螺钉内固定时椎弓根皮质劈裂对骨折椎体稳定性的影响。方法取新鲜成年羊胸腰椎脊柱标本(T14~L2)20具,随机分为A、B两组。在A组和B组标本的L1椎体上分别制作单椎体压缩骨折模型,再单独对B组标本T14胸椎任意一侧的椎弓根行外侧(1/4~1/2)切除,作为椎弓根劈裂椎体骨折模型。然后对A、B两组分别置钉,进钉深度为钉道全长。标本模型固定后,在HY-3080微机控制电子万能材料试验机上,以频率为1.5 Hz的载荷对两组标本模型行10 000次疲劳实验,分别测量疲劳实验后两组标本前屈、后伸、左侧弯、右侧弯4个方向运动范围的大小和疲劳实验后两组标本模型螺钉拔出力大小,并比较两组差异。结果疲劳实验后A组各个方向活动范围:前屈(1.81±0.14)mm,后伸(1.68±0.37)mm,左侧弯(4.08±0.41)mm,右侧弯(4.18±0.12)mm;B组各个方向活动范围大小:前屈(4.49±0.40)mm,后伸(3.72±0.51)mm,左侧弯(6.67±0.64)mm,右侧弯(6.73±0.58)mm;A组各个方向活动范围均小于B组(P0.01)。疲劳实验后A组螺钉最大拔出力为(252.34±51.27)N,B组螺钉最大拔出力为(115.50±36.74)N,最大拔出力A组大于B组(P0.01)。结论椎弓根皮质劈裂将严重影响骨折椎体内固定的稳定性。     

经椎弓根内固定的形态与生物力学研究

目的：提高临床医师对椎弓根内固定技术的理论认识。方法：应用直径４．５ｍｍ,５．５ｍｍ,６．２５ｍｍ和７．０ｍｍ４种不同直径的椎弓根螺钉１６具Ｔ６～Ｓ１节段的新鲜尸体脊柱标本上观察：（１）穿钉失败率;（２）椎弓根膨胀变形率;（３）椎弓根螺钉把持力;（４）椎弓根椎体损伤分类。结果：穿钉失败率与操作技术和椎弓根横径相关,在下胸椎失败率高主要与椎弓根横径密切相关,没有发生穿钉失败的椎弓根膨胀率２８．６％～     

胸腰椎椎弓根螺钉内固定系统的设计进展

椎弓根螺钉内固定系统由于具有牢固的三维固定效果、良好的生物力学稳定性以及较好的复位和矫正畸形作用,被广泛用于脊柱外科,如骨折、退行性变及后凸畸形矫形等治疗,有力地推动了脊柱外科的发展.     

脊柱单节段前中柱切除后不同节段椎弓根螺钉内固定的稳定性测试

目的:比较脊柱单节段前中柱切除后不同节段椎弓根螺钉内固定的稳定性,探讨单节段固定在前中柱病变手术中的可行性。方法:10具小牛新鲜脊柱标本(T10～L5),先测试完整状态下的运动范围(ROM),再模拟L1～L2前中柱病变切除手术:切除L1/2椎间盘和邻近终板共2cm高,行自体髂骨支撑植骨,后路依次用单节段短钉、单节段长钉、短节段和长节段椎弓根内固定系统进行固定,在不同固定方式下测试模型在轴向压缩、侧弯、屈伸和扭转方向上的ROM,计算相对运动范围(RROM)。结果:不同加载方向长节段固定组、短节段固定组的RROM均小于单节段短钉固定组和单节段长钉固定组(P0.05);单节段短钉固定组和单节段长钉固定组的RROM比较无显著性差异(P0.05);单节段短钉固定组和单节段长钉固定组的ROM均小于完整组(P0.05)。结论:小牛新鲜脊柱标本前中柱切除后植骨单节段椎弓根螺钉固定的稳定性低于短节段和长节段固定,但是高于完整状态;脊柱前中柱支撑植骨后,单节段短钉固定与单节段长钉固定的即刻稳定性相近。     

椎弓根螺钉固定的生物力学研究进展

椎弓根螺钉固定性的生物力学研究对提高其固定技术、增强固定的稳定性、减少并发症和改进固定器械起着重要的促进作用。椎弓根的结构特点是椎弓根螺钉固定的解剖基础。螺钉的大小、形状、疲劳特性和椎体的骨密度是影响强度的主要因素,螺道的准备、螺钉的植入点和植入方向以及辅助的椎板钩、骨水泥的应用、合理的植骨是影响固定强度不可忽视的技术因素。椎弓根螺钉固定的体外试验不能很好的反映器械与人体相互作用的生物力学特性,体内研究有待进一步开展。     

椎弓根内固定系统生物力学实验研究

取20具成人尸体腰段脊柱,模拟最严重前中柱损伤模型,通过测定加载方向应变和位移或角度值,比较短节段Roy—Camille、Steffee、Dick、C—D和TPRF5种椎弓根内固定系统在轴向压缩、侧弯、前屈和扭转试验的生物力学稳定性。实验结果表明:器械的稳定程度与椎弓根螺钉直径、螺钉固定装置等结构密切相关。本实验条件下,以TPRF的稳定性最好,但各种器械均不能完全恢复正常脊柱的稳定性。     

椎弓根螺钉内固定技术失误及并发症

目的：探讨胸腰段椎弓螺钉植入失败的原因,预防措施及处理方法。通过回顾性分析椎弓根螺钉手术技术失误及并发症,分析手术技术失误的原因及术后并发症的可能原因,提出预防椎弓根螺钉失败的措施。结果：本组127例。术中操作失误主要是：错位固定2例,椎弓根定位错误5例,复位欠佳3例,骨折过度复位2例,神经损伤2例,术后并发症;螺钉断裂6例,连杆断裂2例,假关节形成2例,矫正度丢失4例,切口裂开2例,占25.2%。结论：椎弓根螺钉技术失误及术后并发症的预防,要求术者具有良好的脊柱解剖知识及脊柱外科手术经验,熟练掌握器材的性能及使用技术要求,椎弓根螺钉的准确定位及准确植入是手术成功的关键。术后配带支具及扶拐功能锻炼,恰当的植骨技术,可减少断钉率及提高植骨融合率。     

椎弓根螺钉内固定治疗腰椎滑脱

１　临床资料１１　一般资料　本组８５例,男５４例,女３１例,年龄３５～６０岁。症状及体征　本组均有顽固性腰痛,间歇性跛行２０例,一侧下肢放射痛５０例,伴一侧大腿酸痛２５例,两侧小腿酸痛１４例。体征：腰椎前凸臀部后凸增加,腰骶部压痛２０例,棘突呈台阶状６８例,直腿抬高试验阳性２３例,膝反射减弱１０例,跟腱反射减弱２５例。Ｘ线片示：腰４双侧椎弓峡部崩裂伴滑脱４５例,腰５双侧弓峡部崩裂伴滑脱３９例,腰５退行性滑脱１例,术前椎体滑脱率最轻为５％,最重为５５％,平均为３０５％。治疗　本组采用Ｓｔｅｆｆ…     

Influence of bone mineral density on pedicle screw fixation : a study of pedicle screw fixation augmenting posterior lumbar interbody fusion in elderly patients

BACKGROUND CONTEXT: Some biomechanical studies have demonstrated that bone mineral density of the lumbar spine (BMD) affects the stability of pedicle screws in vitro. PURPOSE: To investigate influence of BMD on loosening and related failure of pedicle screws in vivo. STUDY DESIGN/SETTING: A clinical study of 52 patients who underwent pedicle screw fixation augmenting posterior lumbar interbody fusion (PLIF). PATIENT SAMPLE: There were 13 men and 39 women, with an average age of 63 years (range, 45-76 years) at the time of operation. The mean follow-up period was 2.8 years (range, 2-6 years). OUTCOME MEASURES: Relationship between BMD, screw loosening, and its related failures were statistically analyzed. METHODS: BMD was measured by the dual energy X-ray absorptiometry (DEXA) method. Radiographic assessments were done by the first author and independently by another orthopedist who was not informed of the values of BMD. RESULTS: The mean BMD of all patients was 0.879 +/- 0.215 (mean +/- S.D.) g/cm2. The mean BMD in patients with and without screw loosening was 0.720 +/- 0.078 g/cm2 (n=11) and 0.922 +/- 0.221 g/cm2 (n=41). There was a significant difference between the mean BMD of patients with and without screw loosening (P<.01). The mean BMD of patients with "union," "nonunion" and "undetermined union" was 0.934 +/- 0.210 g/cm2 (n=40), 0.674 +/- 0.104 g/cm2 (n=4) and 0.710 +/- 0.116 g/cm2 (n=8), respectively. The mean BMD of patients with "union" was significantly greater than those with "nonunion" and "undetermined union" (P<.05). CONCLUSION: It could be concluded that BMD has a close relation with the stability of pedicle screws in vivo, and BMD value below 0.674 +/- 0.104 g/cm2 suggests a potential increased risk of "nonunion" when pedicle screw fixation is performed in conjunction with PLIF.     

体积骨密度与椎弓根螺钉稳定性的相关性及磷酸钙陶瓷的强化效应

目的探讨椎体松质骨体积骨密度对椎弓根螺钉稳定性的影响,以及添加磷酸钙陶瓷的效应.方法用pQCT测定16个腰椎的体积骨密度,将USS椎弓根螺钉分别置人两侧椎弓根,植入螺钉前随机在其中一侧钉道内添加磷酸钙陶瓷;测试螺钉最大轴向拔出力（F-max）,计算骨螺钉界面的剪切应力（η）.结果随体积骨密度提高,F-max和η亦逐次增加.无论是否添加磷酸钙陶瓷,F-max和体积骨密度始终呈较强的正相关关系（r=0.9056和0.9585,P＜0.05）.添加磷酸钙陶瓷后F-max和η均增加了约80%（Wilcoxon＇s test,P＜0.01）.结论椎弓根螺钉的稳定性与体积骨密度紧密相关,磷酸钙陶瓷有明显的强化效应.     

增加载荷分享的动力内固定对椎体骨量和骨结构的影响

目的分析比较动力椎弓根螺钉内固定与相对坚强内固定对固定区椎体骨密度和骨结构的影响,探讨增加载荷分享的意义。方法24只山羊随机分为四组,每组6只。对照组:仅行脊柱椎旁肌剥离;单纯植骨融合组:切除L3后部结构,行后外侧植骨融合;坚强固定融合组:在脊柱不稳模型上行相对坚强内固定及后外侧植骨融合;动力固定融合组:在脊柱不稳模型上行动力椎弓根螺钉内固定及后外侧植骨融合。术后24周处死动物,取腰椎标本。采用定量计算机断层扫描法(QCT)测定腰椎标本固定区椎体松质骨的骨密度。在普通显微镜下观察固定区椎体骨小梁结构;并行骨形态计量学分析,计算骨小梁体积比、平均骨小梁间距、平均骨小梁厚度和骨矿化沉积速度。结果与对照组比较,坚强固定融合组的骨密度明显下降(P< 0.01);而动力固定融合组与对照组比较差异无显著性。与对照组和单纯植骨融合组比较, 坚强固定融合组的骨小梁体积比、平均骨小梁厚度和骨矿化沉积速度均明显下降(P< 0.01),平均骨小梁间距明显增加(P< 0.05);而动力固定融合组与对照组比较各项参数的差异无显著性。光镜下可观察到坚强固定融合组固定区椎体有骨质疏松改变。结论坚强内固定对固定区椎体有应力遮挡效应;而动力椎弓根螺钉固定器能增加载荷分享,有效缓解应力遮挡效应。     

The insertional torque of a pedicle screw has a positive correlation with bone mineral density in posterior lumbar pedicle screw fixation

In patients with osteoporosis there is always a strong possibility that pedicle screws will loosen. This makes it difficult to select the appropriate osteoporotic patient for a spinal fusion. The purpose of this study was to determine the correlation between bone mineral density (BMD) and the magnitude of torque required to insert a pedicle screw. To accomplish this, 181 patients with degenerative disease of the lumbar spine were studied prospectively. Each underwent dual-energy x-ray absorptiometry (DEXA) and intra-operative measurement of the torque required to insert each pedicle screw. The levels of torque generated in patients with osteoporosis and osteopenia were significantly lower than those achieved in normal patients. Positive correlations were observed between BMD and T-value at the instrumented lumbar vertebrae, mean BMD and mean T-value of the lumbar vertebrae, and mean BMD and mean T-value of the proximal femur. The predictive torque (Nm) generated during pedicle screw insertion was [-0.127 + 1.62 × (BMD at the corresponding lumbar vertebrae)], as measured by linear regression analysis. The positive correlation between BMD and the maximum torque required to insert a pedicle screw suggests that pre-operative assessment of BMD may be useful in determining the ultimate strength of fixation of a device, as well as the number of levels that need to be fixed with pedicle screws in patients who are suspected of having osteoporosis.     

骨水泥修复颈椎前路椎体螺钉钉道的生物力学研究

目的 评价聚甲基丙烯酸甲酯(Polymethylmethacrylate,PMMA)修复颈椎前路椎体螺钉钉道的生物力学效果。方法 防腐成人颈椎标本(C_3~7)共30个,分3组:正常骨密度组(A组)、骨质疏松组(B组),骨质疏松修复组(C组),各组10个标本,测试疲劳前后的最大轴向拔出力。A、B对照组椎体二侧钉孔均放置4 mm的椎体螺钉,随机选择一侧行即时最大拔出力实验,另一侧在疲劳实验(2 Hz,20 000次)后行最大拔出力实验。C组(实验前需进行螺钉拔松实验)注入PMMA 0.6~1.0 mL,并拧入螺钉,随机选择一侧进行即时和疲劳后最大拔出力实验。结果 A、B、C组即时拔出力明显高于疲劳后拔出力,差异具有统计学意义(P< 0.05),C组疲劳后与A组即时拔出力比较,差异无统计学意义(P >0.05),但高于B组即时拔出力,差异具有统计学意义(P< 0.05)。即时拔出力C组 >A组 >B组,差异均有统计学意义(P< 0.05)。疲劳后拔出力C组 >A组 >B组,差异均有统计学意义(P< 0.05)。PMMA注射后未发现钉道渗漏。结论 PMMA钉道修复能够明显增强椎体螺钉的即时稳定性和抗疲劳能力, 并且安全有效,适用于螺钉松动和拔出的修复固定。     

滑动椎弓根钉系统稳定性体外生物力学测试

[目的]对滑动椎弓根钉系统(SPSS)与通用椎弓根钉系统(USS)在脊柱侧凸固定强度、刚度和稳定性等方面进行生物力学比较,以测试滑动椎弓根螺钉内固定系统稳定性的生物力学性能.[方法]采用12具猪新鲜脊柱标本,随机分成两组分别测量不同工况下T12椎体的位移,并计算其强度和刚度进行比较.[结果]滑动组和通用组无论在轴向压缩、前屈、后伸、侧屈情况下,主应变、位移变化及固定强度、刚度均无显著性差异(P>0.05).[结论]滑动椎弓根钉系统治疗脊柱侧凸同样能够达到通用椎弓根钉系统相同的矫形效果及生物力学稳定性,同时它不影响青少年生长发育.     

可注射硫酸钙MIIGX3与医用骨水泥对椎弓根钉固定作用的比较研究

[目的]用可注射硫酸钙M IIGX3(m in im ally invasive in jectab le graft X3,以下简称M IIGX3)及医用骨水泥分别强化猪腰椎椎弓根钉内固定,测定椎弓根钉最大轴向拔出力,比较两种材料对椎弓根钉固定强度的影响。[方法]8个新鲜猪腰椎作为实验对象,在同一椎体双侧椎弓根制作钉道,一侧在固定螺钉前加用M IIGX3(M IIGX3组),另一侧加用骨水泥(骨水泥组)。24 h后行轴向拔出力测试。[结果]最大轴向拔出力,M IIGX3组1915±375 N,骨水泥组3625±775 N,二者配对t检验有显著差异(P<0.01)。[结论]骨水泥对椎弓根钉的固定作用大于M IIGX3。当存在脊柱滑脱需较大提拉力量或椎弓根钉需承受较大拔出力的节段,使用骨水泥进行强化更为合适。     

A biomechanical study on fixation stability with twin hook or lag screw in artificial cancellous bone

The twin hook has been developed as an alternative to the conventional lag screw to be combined with a barrelled side-plate in the treatment of trochanteric hip fractures. With two oppositely directed apical hooks introduced into the subchondral bone of the femoral head, the twin hook provides different stabilising properties to the lag screw. The femoral head purchase of the twin hook and the lag screw were compared in a biomechanical study using artificial cancellous bone, and responses to axial and torsional loading was determined. A distinct yield point in load and torque was noted for the lag screw, representing failure of the laminas supporting the threads. For the twin hook, gradual increase of load and torque occurred during impaction of the bone supporting the hooks. The peak loads and torques were higher for the lag screw, but were similar for both devices after 8 mm deformation. The stiffness was higher for the lag screw, but in counter-clockwise rotation the stiffness for the lag screw was negligible. The twin hook appeared to provide fixation stability comparable to that offered by the lag screw, but with conceivable advantages in terms of a deformation response involving bone impaction and gradually increasing stability.     

椎弓根螺钉设计与其生物力学稳定性的研究进展

<正>椎弓根螺钉内固定术是治疗脊柱疾病的主要方式之一[1],而螺钉松动是椎弓根螺钉内固定术的常见并发症[2],骨质疏松是引起螺钉松动的重要因素之一,其发生率高达60%[3]。有研究报道,当胸腰椎的骨密度时,椎弓根螺钉的生物力学稳定性明显下降[4]。测试椎弓根螺钉的生物力学稳定性指标主要有抗拔出力、疲劳强度、刚度、拧入扭矩[5-9]等。有研究表明,用聚甲基丙