【作者】 付索超；

【导师】 雷伟；

【作者基本信息】 第四军医大学 ， 外科学， 2010， 博士

【摘要】 椎弓根螺钉因具有三柱固定、固定牢靠、利于维持重建脊柱序列等特点,已经在世界范围内被广泛的应用于脊柱疾病的治疗。随着老龄化社会的来临,骨质疏松症发病率逐渐增多。骨质疏松患者并发椎体骨折、感染、退行性变或肿瘤等需椎弓根螺钉内固定时,常因骨质条件差,术中难于稳定、术后容易松动脱落,最终导致内固定的失败。如何提高骨质疏松条件下椎弓根螺钉的稳定性,已成为当今骨科学界的一大难题。我们通过自行设计不同孔数的强化材料注射器(由不同孔数的侧孔或直孔鞘和推杆组成),对骨质疏松条件下生物力学测试模块和新鲜人体腰椎标本进行钉道局部和整体强化,比较不同孔数强化剂注射器对钉道强化的作用,寻找最佳解决方案,以期提高椎弓根螺钉的把持力。实验一不同孔数强化剂注射器联合应用丙烯酸树脂骨水泥(acrylic bone cement, ABC)对骨质疏松椎弓根钉道强化的研究目的:比较不同孔数强化剂注射器联合ABC注射对骨质疏松椎弓根钉道的强化作用。方法:采用美国Pacific Research Laboratory公司生产的聚氨酯(polyurethane,PU)生物力学测试模块模拟人骨质疏松松质骨的力学性能。利用自行设计的不同孔数的侧孔和直孔骨水泥注射装置,对椎弓根钉道分别施行不同形式的强化,分为4孔、6孔、8孔侧孔鞘局部钉道强化组、直孔鞘全钉道强化组和空白对照组。对所有力学试验模块采用直径3.5mm手钻常规制备钉道,深度45mm。侧孔组沿钉道插入侧孔鞘至45mm,向鞘内推注2.5ml已调制呈膏体状的ABC骨水泥,以推杆将鞘内残存骨水泥完全推至鞘外,全钉道组沿钉道插入直孔鞘后,边向鞘内推注骨水泥,边退出鞘,用推杆将鞘内残留骨水泥完全推至钉道中。待骨水泥未完全硬化时,使用扭矩扳手以3转/分匀速旋入CD HORIZON M8椎弓根螺钉(规格:6.5mm×45mm)。对照组不注射任何材料,直接旋入螺钉。各组旋入螺钉均为6枚。记录最大植入扭矩。常规行X线、CT检查,24小时后用MTS858型万能材料试验机行螺钉轴向拔出力试验。数据结果采用SPSS11.5统计软件包进行分析。结果:不同强化组的骨水泥分布不同,呈现规律性。4孔组骨水泥大致位于螺钉尾侧1/3,6孔组位于螺钉中间1/3,8孔组位于螺钉头侧1/3及以远,全钉道组沿钉体全长环形分布。侧孔及全钉道强化组螺钉的最大轴向拔出力较空白组均有显著增加,8孔组拔出力低于4孔、6孔及全钉道组,差别具有统计学意义。4孔、6孔及全钉道组组间差别无统计学意义。旋入扭矩在各强化组两两之间无差别,均较对照组有显著增加,差别具有统计学意义。螺钉拔出后骨水泥与聚氨酯材料的界面发生断裂,而与螺钉形成致密包裹。结论:不同孔数的强化剂注射器联合ABC骨水泥注射,可显著提高螺钉最大拔出力,8孔鞘容易发生渗漏,缺乏安全性,且拔出力相对较小。4孔、6孔鞘局部强化均可起到与全钉道强化相似的的作用。实验二不同孔数强化剂注射器联合应用磷酸钙骨水泥(calcium phasphite cement,CPC)对骨质疏松椎弓根钉道强化的研究目的:比较不同孔数强化剂注射器联合CPC注射对骨质疏松椎弓根钉道的强化作用。方法:采用美国Pacific Research Laboratory公司生产的PU模块模拟人骨质疏松松质骨的力学性能。利用自行设计的不同孔数的侧孔和直孔骨水泥注射装置,对椎弓根钉道分别施行不同形式的强化,分为4孔、6孔、8孔侧孔鞘局部钉道强化组、直孔鞘全钉道强化组和空白对照组。每组样本量均为6个。对所有力学试验模块采用直径3.5mm手钻常规制备钉道,深度45mm。侧孔组沿钉道插入侧孔鞘至45mm,向鞘内推注2.5ml已调制呈膏体状的CPC骨水泥,以推杆将鞘内残存骨水泥完全推至鞘外,全钉道组沿钉道插入直孔鞘后,边向鞘内推注骨水泥,边退出鞘,用推杆将鞘内残留骨水泥完全推至钉道中。待骨水泥未完全硬化时,使用扭矩扳手以3转/分匀速旋入CD HORIZON M8椎弓根螺钉(规格:6.5mm×45mm)。对照组不注射任何材料,直接旋入螺钉。记录最大植入扭矩。常规行X线、CT检查,24小时后用MTS858型万能材料试验机行螺钉轴向拔出力试验。数据结果采用SPSS11.5统计软件包进行分析。结果:不同强化组的骨水泥分布不同,且呈现规律性。4孔组骨水泥大致位于螺钉头侧1/3,6孔组位于螺钉中间1/3,8孔组位于螺钉尾侧1/3,全钉道组沿钉体全长分布。侧孔及全钉道强化组螺钉的最大轴向拔出力较空白组均有显著增加,8孔组拔出力低于4孔、6孔及全钉道组,差别具有统计学意义。4孔、6孔及全钉道组组间差别无统计学意义。旋入扭矩在各强化组两两之间无差别,均较对照组有显著增加,差别具有统计学意义。螺钉拔出后骨水泥与聚氨酯材料的界面发生断裂,而与螺钉形成紧密包裹。结论:不同孔数的强化剂注射器联合CPC骨水泥注射,可显著提高螺钉最大拔出力,8孔组拔出力较小,相对容易发生强化材料渗漏,缺乏使用安全性。4孔、6孔鞘局部强化均可起到与全钉道强化相似的的作用。实验三同种侧孔强化剂注射器应用ABC及CPC对骨质疏松椎弓根钉道局部强化的对比研究目的:比较孔数相同的侧孔强化剂注射器应用ABC及CPC对PU模块椎弓根钉道局部强化的作用。方法:采用美国Pacific Research公司生产的PU模块。按强化方式分成6组,4孔鞘注射ABC、CPC组,6孔鞘注射ABC、CPC组,8孔鞘注射ABC、CPC组。常规制备直径3.5mm钉道,分别置入自制4孔、6孔及8孔侧孔鞘,连接5ml注射器,注射已调制呈膏体的ABC或CPC骨水泥2.5ml,进行钉道的局部强化。24小时后用MTS858型万能材料试验机行螺钉最大轴向拔出力测试。数据分析采用SPSS11.5统计软件。结果:使用相同孔数的侧孔注射器进行注射,骨水泥在螺钉周围的分布具有相似性。对于相同孔数的侧孔鞘,联合注射ABC较之CPC对钉道产生更好的强化作用,椎弓根螺钉具有更大的轴向拔出力。4孔、6孔及8孔鞘组各组间统计学上均存在差异。结论:使用侧孔强化材料注射器联合应用ABC与CPC均可增加骨质疏松条件下椎弓根螺钉的轴向拔出力,但是使用相同孔数的强化注射器,ABC具有更好的强化作用。实验四不同孔数强化剂注射器应用ABC和CPC对新鲜人骨质疏松标本腰椎椎弓根钉道的强化研究目的:基于前述实验结果,比较4、6侧孔和直孔强化剂注射器联合ABC和CPC注射对新鲜人腰椎骨质疏松标本椎弓根钉道的强化作用。方法:从9具人新鲜冰冻尸体标本(年龄46~67岁),获取可用腰椎标本42个。经双能X线吸收法(DEXA法)检测证实骨密度介于0.63~0.78g/cm2之间。按照完全随机化设计,将所有椎体分为A、B两组,每组再随机化分为ABC+4侧孔组、ABC+6侧孔组、ABC+全钉道组、CPC+4侧孔组、CPC+6侧孔组、CPC+全钉道组和空白对照组。各组间骨密度值无显著差别(P>0.05)。按照“人字嵴”顶点法,常规制备钉道,直径3.5mm,深度45mm。侧孔强化组及全钉道注射组注射牙膏状ABC或CPC,每侧椎弓根注射量约2.5ml,置钉后对椎体行X线检查、CT三维重建。常温下保存24小时后于MTS 858万能试验机上进行椎弓根螺钉轴向拔出和周期抗屈试验。结果:X线、CT重建发现其4孔组骨水泥位于椎体内,6孔组位于椎体和椎弓根部,全钉道组形成完全包绕。使用强化材料注射器强化过程中,所有椎体均未见骨水泥明显返流渗出等情况。使用ABC和CPC组,6孔组螺钉最大轴向拔出力均与全钉道灌注组无统计学上的差别,均高于4孔组,明显高于空白组,差异具有统计学意义。周期抗屈试验表明,经过10,000个周期循环加载后,ABC组,6孔与4孔和全钉道组两两间无统计学差别,均明显强于空白组;CPC组有类似的结果。结论:6孔强化剂注射器,无论联合使用ABC还是CPC骨水泥,对骨质疏松椎体均能起到强化椎弓根钉道的作用,具有较大的轴向拔出力,同时具有良好的周期抗屈能力,保留了钉-骨界面,可以代替全钉道灌注应用于骨质疏松条件下的椎弓根钉道强化。更多还原

【Abstract】 The pedicle screw has been used world widely in the treatment of spinal disorders currently for its characteristic of 3-dimensional column fixation, convincing stabilization and maintaining the reconstructed spinal alignment. With the advent of an aging society, the amount of patients suffering from osteoporosis has been rapidly increasing. The population suffering from spinal fractures, infections, degeneration, tumors and so on, with osteoporosis who need to have vertebrae internal fixation will usually encounter such an embarrassing condition that the bone bed was too poor to have pedicle screw fixation done. Thus, how to augment the stability of a pedicle screw fixation seems an urgent and necessary problem to be tackled. In this study, we attempted to use the self-designed enhancer-injector with different number of holes to augment conventional pedicle screws’stability, to compare the differences among different groups, first on mechanical test blocks then further on the cadaveric lumbar specimen,and finally to find a better soluble method to augment the pedicle fixation in osteoporosis condition.. 1 The study of a pedicle screw channel augmentation with acrylic bone cement by enhancer-injectors with different number of holesObjective: To compare the effects of enhancer-injectors with different number of holes on the pedicle screw channel augmention. and to select a better one. Methods: The biomechanical test blocks (The Pacific Research Laboratory Corp. USA) were used in our study as a simulation of the biomechanical character of human osteoporotic cancellous bone. To use the enhancer-injector with different number of holes to augement a pedicle screw channel in different ways. The experimental groups can be divided into the following five groups as a 4-sided-hole, 6-sided-hole, 8-sided-hole, local augmentation groups, and a full-length augmentation group respectively. The control group referred to is that where pedicle screws were inserted without any cement augmentation. A 3.5 mm diameter hand drill was used to prepare the pedicle screw channel in the biomechanical test blocks to the upper surface with a depth of 45 mm. In the experimental groups, the novel sided-holes or straight-hole were inserted into the block along the prepared channel. In the sided-hole groups, the sheath was inserted along the prepared channel, and 2.5ml of ABC was injected into the sheath. Then a steel-rod was put into the cannulated sheath to push out the remainder of the cement to the testing block. In the full-length group, the straight-hole sheath was inserted into the channel along the prepared hole and to inject the cement as withdrawing. Before the cement was hardened, the CD HORIZON M8 pedicle screw (size: length 45mm, diameter 6.5mm; Sofamor Danek Corp.) was inserted into the channel with a manual torque wrench at a rate of 3 rev/min evenly. The pedicle in the control group was inserted into the block without any cement injection. The maximum insertion torque was recorded. The pedicle screw’s maximum axial pullout strength in each group was tested by a MTS 858 machine after 24 hours. Results: The pedicle screw’s maximum pullout strength of each group augmented by a 4-sided-hole, 6-sided-hole, 8-sided-hole, and a full-length novel device, which was respectively higher than that of the control group. Among the experimental groups, the 8-sided-hole group had lower screw pullout strength than the other threes, and the difference was statistically significant. There were no differences between the 4-sided-hole, 6-sided-hole and the full-length groups each. There also was no difference between the insertion torque. The distribution of the ABC injected by enhancer-injector with different number of holes presented regularity. The cement of the 4-sided-hole group distributed along the distal one third length of the screw. And in the 6-sided-hole group, the ABC distributed from the proximal one-third point of the screw to the distance, and in the 8-sided-hole group, the ABC distributed along the proximal one third length. Conclusion: The enhancer-injectors with different number of holes can be used to augment the pedicle screw channel by combining with ABC. The pedicle screw augmented by a 4-or 6-sided-hole sheath may have similar maximum axial pullout strength as the full-length cement injection with the same amount of 2.5ml cement. However, the 8-sided-hole enhancer-injector may result in relatively lower pullout strength and has the possibility of cement extravasation as well as cement solidarization near the screw head. Both the 4 and 6-sided-hole novel devices could be used to augment the pedicle screw channel.2 The study of a pedicle screw channel augmentation with calcium phasphite cement by enhancer-injectors with different number of holesObjective: To evaluate the effects of enhancer-injectors with different number of holes on the pedicle screw channel augmentation. Methods: The biomechanical test blocks (The Pacific Research Laboratory Corp. USA) were used in our study as a simulation of the biomechanical character of human osteoporotic cancellous bone. To use the enhancer-injector with different number of holes to augement a pedicle screw channel in different ways. The experimental groups can be divided into the following five groups as a 4-sided-hole, 6-sided-hole, 8-sided-hole, local augmentation groups, and a full-length augmentation group respectively. The control group referred to is that where pedicle screws were inserted without any cement augmentation. The 3.5 mm diameter hand drill was used to prepare the pedicle screw channel in the biomechanical test blocksrly to the upper surface with a depth of 45 mm. In the experimental groups, the novel sided-holes or straight-hole were inserted into the block along the prepared channel. In the sided-hole groups, the sheath was inserted along the prepared channel, and 2.5ml of CPC was injected into the sheath. Then a steel-rod was put into the cannulated sheath to push out the remainder of the cement to the testing block. In the full-length group, the straight-hole sheath was inserted into the channel along the prepared channel and to inject the cement as removing. Before the cement was hardened, the CD HORIZON M8 pedicle screw (size: length 45mm, diameter 6.5mm; Sofamor Danek Corp.) was inserted into the channel with a manual torque wrench at a rate of 3 rev/min evenly. The pedicle in the control group was inserted into the block without any cement injection. The maximum insertion torque was recorded. The pedicle screws’maximum axial pullout strength in each group was tested by a MTS 858 machine after 24 hours. Results: The distribution of the CPC injected by enhancer-injector with different number of holes present regularity. The cement of the 4-sided-hole group distributed along the distal one third length of the screw. And in the 6-sided-hole group, the CPC distributed from the one third point of the screw to the distance. In the 8-sided-hole group, the CPC distributed along proximal one third length. The pedicle screw’s mean maximum pullout strength of each group augmented by a 4-sided-hole, 6-sided-hole, 8-sided-hole, and a full-length novel device, which was respectively higher than that of the control group. Among the experimental groups, the 8-sided-hole group had lower screw pullout strength than the other threes, and the difference was statistically significant. There were no differences between the 4-sided-hole, 6-sided-hole and the full-length groups each. There also was no difference between the insertion torque. Conclusion: The enhancer-injector with device can be used to augment the pedicle screw channel by combining with CPC, a pedicle screw, and augmented by a 4-or 6-sided-hole. They all have similar maximum axial pullout strength as the full-length cement injection with the same amount of cement which was 2.5 ml. However, the 8-sided-hole novel device may result in a lower pullout strength and has the possibility of cement extravasation as well as cement solidarization near the screw head. Both the 4 and 6-sided-hole novel devices could be used to augment the pedicle screw channel.3 The evaluation of axial pullout strength of the pedicle screw augmented with ABC and CPC by sided-holes enhancer-injector of the same type.Objective: To compare the effects of a pedicle screw fixation augmented locally with ABC and CPC cement via enhancer-injector of the same sided-holes number .Methods: The osteoporotic biomechanical test blocks made in the USA by the Pacific Research Corp. were used here as a simulation for the biomechanical characteristics of an osteoporotic cancellous vertebral bone. Pedicle screws were augmented by a novel 4-sided-hole, 6-sided-hole, 8-sided-hole device with ABC and CPC respectively. A 3.5 mm diameter hand drill was used to drill into the biomechanical test blocks and all of the blocks in our test were drilled to a depth of 45 mm. The sided-hole novel devices were inserted into the block perpendicularly to the block upper-surface along the prepared channels, and then were connected to a 5 ml capacity syringe. Having mixed ABC cement to a tooth-paste state, 2.5ml of cement was injected into the novel device, then the syringe was removed and the use of a custom-designed rod to push the remainder of the cement. CPC cement was injected into the biomechanical test blocks with the same procedures of the ABC cement. Results: The pedicle screws’maximum pullout strength of the groups augmented with ABC cement had a respective statistical difference than with groups augmented by CPC cement with a 4-sided-hole, 6-sided-hole, 8-sided-hole novel device. SPSS 11.5 statistical software package was used to analyze the data. Conclusion: Both ABC and CPC can be used to augment the pedicle screw via enhancer-injector and by the same type of the novel sided-hole device, a pedicle screw locally augmented with ABC had higher mean maximum axial pullout strength than CPC.4 The biomechanical study of a pedicle screw fixation augmented by ABC and CPC respectively on fresh-frozen cadaveric osteoporotic vertebrae by enhancer-injectorObjective: To study the effects of the enhancer-injectors with different number of holes on pedicle screw fixation augmentation by ABC and CPC on the cadaveric osteoporotic vertebrae. Methods: Forty-two lumbar vertebrae from 9 human fresh-frozen, donated corpses were collected. Discs and soft tissues were removed completely and the 3 vertebrae with severe deformation were excluded. The BMD was also examined by DEXA. The total of 42 vertebrae was randomized into two groups. One group was ready to test the axial pullout strength, and the other group was ready to do the cephaladcaudal cyclic fatigue test. For each group, they were randomized into seven subgroups even further. Among the groups, the BMD value showed no stastically different each. (P>0.05)The experimental groups were augmented with ABC by 4-sided-holes, 6-sided-holes, full-channel-length, and with CPC by 4-sided-holes, 6-sided-holes, full-channel-length. The control group was referred to by that group where the pedicle screws were inserted without any cement. According to the“Chevron pointing”method, the pedicle screw channel of a 45 mm length was conventionally prepared by a 3.5 mm diameter hand drill. The sided-hole sheath was inserted into the pedicle screw channel, and a total of 2.5 ml ABC or CPC was injected into each pedicle via the novel side-hole device. The full-length pedicle screw channel augmentation was carried out by the straight-hole sheath by injection as withdrawing. The X-ray and CT renconstruction were carried out. After 24 hours conservation at room temperature, the maximum axial pullout strength and cephalocaudal cyclic fatigue test were carried out by MTS 858 machine. Results: By X-ray and CT renconstruction, it can be seen that the cement of the 4-sided-hole group mainly distributed in the vertevrae body, and in the 6-sided-hole group, the cement distributed both in the latter of the vertebral body and the pedicle, in the full-channel group, it distributed along the whole channel. In the axial pullout test, the 6-sided-hole group had a significant higher pullout strength than that of the 4-sided-hole group and it showed no statistical difference between 6-sided-hole group and full-length group. In the CPC augmentation group, we got the similar results from the CPC augmentation group. In the cephalocaudal cyclic fatigue test, the pedicle screws augmented by 6-sided-hole novel device had the highest mean maximum axial pullout strength among the ABC augmentation groups, and it was similar in the CPC cement augmentation groups. In the cephalocaudal cyclic fatigue test, the 6-sided-hole group had the least displacement of pedicle screw head, and had showed a significant difference from the other groups. Conclusion: The 6-sided-hole enhancer-injector could provide as stable as the full-length-channel group, and has the higher axial pullout strength. It has also remained the screw-bone interface, and can be recommeded as an effective way to augment the screw channel, especially in the osteoporotic conditions, either with ABC or CPC.更多还原