节段开窗髓核摘除对腰椎稳定性的影响

目的 本研究观察了腰椎椎板节段开窗髓核摘除对腰椎稳定性的影响。方法 ７具新鲜腰骶椎标本头尾端固定,模拟人体行屈曲,侧弯和旋转活动,随后顺序进行Ｌ３－Ｓ１椎板节段开窗及Ｌ４－５,Ｌ５,Ｓ１髓核摘除,对比观察术前和多节段椎板双侧开窗及髓核摘除术后腰椎各节段在三维空间的位移变化,结果 单纯多节段开窗后屈江活动时Ｌ４,５前后水平和轴向位移分别增加１８％和１６％,Ｌ５Ｓ１则分别增加１９％和４５％,椎板开窗加     

椎间盘的解剖与理化性能（一）

椎间盘的解剖与理化性能（一）郭世绂椎间盘自Ｃ（２～３）直到Ｌ５～Ｓ１均存在，与相邻上下椎体形成运动节段。椎间盘自上向下逐渐增厚。颈、腰部活动多，椎间盘较厚。全部椎间盘的厚度约占脊柱全长的１／３，腰部椎间盘最厚，几占全部椎间盘厚度的一半。Ｌ５～Ｓ１的椎...     

腰椎髓核摘除术后椎间隙炎8例报告

腰椎髓核摘除术后椎间隙炎８例报告郑州河南省武警总队医院骨科（４５００５２）吴宝全自１９８８～１９９３年共行腰椎髓核摘除术２４６例，术后合并椎间隙炎８例。其中男５例，女３例。年龄３２～５９岁，平均４６岁。部位Ｌ４．５４例，Ｌ５Ｓ１３例，Ｌ４．５Ｌ５Ｓ１...     

PLD与APLD治疗腰椎间盘突出症比较

现对我院１９９３年～１９９５年间采用ＰＬＤ与ＡＰＬＤ切割治疗腰椎间盘突出症患者９６例进行分析、比较。临床资料ＰＬＤ组：５１例中男３７例，女１４例；年龄２０～５８岁；病程１月～１２年，其中３年以内４２例，３年以上９例；病变节段１节椎间盘突出者４５例，２节突出者５例，３节突出者１例；Ｌ_（３～４）椎间盘３节，Ｌ_（３～４）；椎间盘４３节，Ｌ_５～Ｓ_１椎间盘１３节（共５９节椎间盘）。ＡＰＬＤ组：４５例中男３１例，女１４例；年龄２３～６１岁；病程２周～８年，其中３年以内４１例，３年以上３例；病变节段１节椎…     

腰椎间盘转移性腺癌4例报告

腰椎间盘转移性腺癌４例报告郑文忠，林其仁，马国棣，郑季南１９８０年以来，我们施行腰髓核摘除术８７０例，其中４例为腰椎间盘转移性腺癌，现报告如下。１临床资料４例均为男性，年龄５６～７０岁，平均６０岁。病变位于Ｌ４～５椎间盘２例，Ｌ５～Ｓ１椎间盘２例；左...     

腰神经根解剖及其在经皮穿刺腰椎间盘摘除术中的临床意义

目的加深对腰神经根周围解剖的认识,选择经皮穿刺最佳途径。方法对３０具成人尸体腰神经根周围结构进行解剖学观察、测量和摹拟穿刺。结果测量三角工作区面积（ｍｍ２）：Ｌ４～５为１０４６５±２３６６,Ｌ５～Ｓ１为９１８１±１６７８;直视下穿刺针进入角度（°）：Ｌ４～５为４５３３±１８１,Ｌ５～Ｓ１为４０４３±３４９,外区为４８４±２５６;穿刺点距后中线距离（ｍｍ）：Ｌ４～５为６９８±５７,Ｌ５～Ｓ１为６０６±７０,外区为９７１±９９;闭合穿刺成功率：Ｌ４～５为１００％,Ｌ５～Ｓ１为９０％,外区为６０％。结论经三角工作区穿刺是经皮后外侧入路腰椎间盘摘除术的最佳途径;对Ｌ５～Ｓ１间隙穿刺有困难时,可经三角工作区的外区进行穿刺手术。     

腰椎矢状面固定角度对相邻椎间盘内压的影响

目的通过体外生物力学实验评价腰椎矢状面固定角度对上位相邻椎间盘内压的影响。方法10具人新鲜尸体腰椎标本L3～S2用于实验。完整脊柱测试后,在每个标本的L4/L5椎间用椎弓根钉随机顺序地进行矢状面三种角度的固定:①原位(前凸10°)。②后凸位(后凸5°)。③超前凸位(前凸25°)。每组分别行载荷量为6N·m的前-后屈曲试验,记录相邻节段L3/L4椎间盘内压,并加以比较。结果在前屈试验中,所有固定组的相邻间盘内压均显著高于完整脊柱组,后凸位固定组的椎间盘内压最高。在后屈试验中,后凸位固定的L3/L4椎间盘内压显著高于其他固定组;但完整脊柱、原位固定和超前凸固定组间无显著差异。结论脊柱固定可导致相邻节段的应力增加,并且矢状面异常固定角度会更加破坏其生物力学环境。在腰椎稳定重建中,应该获得正常椎间前凸角。     

经皮弧式椎间盘切除器械治疗腰5骶1椎间盘突出症初步报告

采用经皮弧式椎间盘切除器械治疗Ｌ_５～Ｓ_１椎间盘突出症２２例，２１例成功。术后优良率为８６．４％。该器械能够避开髂嵴阻挡进入Ｌ_５～Ｓ_１椎间隙，并增加椎间盘切除量，提高经皮Ｌ_５～Ｓ_１椎间盘切除成功率。定位正确是成功的关键。     

胸腰段僵硬性角状后凸畸形对下腰椎的影响及外科治疗

目的 探讨胸腰段僵硬性后凸畸形对腰椎的影响及其临床意义。方法 测量１４例后凸畸形截骨手术治疗前后的胸腰段后凸角和Ｌ２－５、Ｌ２～Ｓ１、Ｌ２－３、Ｌ３－４、Ｌ４－５、Ｌ５～Ｓ１的前凸角以及椎体滑移的情况,对所得结果与正常组进行对比分析。结果畸形组腰椎前凸及Ｌ２－３、Ｌ３－４、Ｌ４－５前凸角明显大于正常组,而且Ｌ２－３、Ｌ３－４前凸增加幅度更大,术后腰椎过度前凸有明显矫正,但仍然大于正常组;畸形组有     

椎间盘摘除术后残留间盘组织再脱出至椎管梗阻1例报告

椎间盘摘除术后残留间盘组织再脱出至椎管梗阻１例报告李建民，邢继平，毛岩，刘成患者，男，３８岁。左腰椎间盘摘除术后８个月，腰腿痛复发４个月。患者于１９９２年４月２０日行Ｌ５－Ｓ１椎间盘摘除术，术后恢复良好。１９９２年１２月５日，患者咳嗽后觉左腰骶部剧烈...     

Stability of the whole lumbar spine after multilevel fenestration and discectomy.

STUDY DESIGN: An investigation of the in vitro biomechanical effects of multilevel fenestrations and discectomies on the behavior of whole lumbar spine motion, using a material testing system (Instron 1341, Instron Limited, High Wycombe, England) and Elite three-dimensional motion analysis system (BTS, Milano, Italy). OBJECTIVES: To investigate the effects of multilevel fenestrations and discectomies on the stability of the whole lumbar spine, including segmental stiffness and sagittal (horizontal and vertical) translation. SUMMARY OF BACKGROUND DATA: In the management of lumbar spinal stenosis, wide decompressive laminectomy with partial or total facetectomy has been the standard procedure for multilevel nerve decompression. Main complications with these procedures have been instability and chronic pain syndrome. Multilevel fenestration with undermining enlargement of the spinal canal has been selected for multilevel nerve decompression in recent years. However, the biomechanical effects of multilevel fenestration and discectomy have been controversial and difficult to validate. This study investigated the in vitro biomechanical effects of multilevel fenestrations and discectomies on motion behavior of the whole lumbar spine. METHODS: Seven fresh human specimens from L1 to sacrum were used in this study. The fenestrations and discectomies consisted of L3-L4 bilateral fenestration, L4-L5 bilateral fenestration, L5-S1 bilateral fenestration, L4-L5 discectomy, and L5-S1 discectomy. Flexion, lateral bending, and axial rotation (torsion) loading were applied. Ranges of motion were determined two-dimensionally by the Elite system with an infrared camera. The postoperation results were compared with the intact conditions. RESULTS: After multiple fenestrations, the sagittal ranges of motion at L4-L5 increased by 18% anteroposteriorly and 16% vertically under the flexion loads. At L5-S1, the motions increased by 19% and 45%, respectively. After fenestrations and discectomies, the ranges of motion in the sagittal plane increased by 28% horizontally and 71% vertically at L4-L5, and 14% and 166% at L5-S1. Motion increases were statistically significant (P < 0.05) in vertical translations. However, after the multilevel surgeries, no significant motions were found in each of the lumbar segments during lateral bending and axial rotation. CONCLUSIONS: The results demonstrate that multilevel fenestrations and discectomies affect lumbar spinal stability in flexion, but have no effect on the stability of the lumbar spine in lateral bending or axial rotation.     

Kinematics of the whole lumbar spine. Effect of discectomy

The biomechanical effects of discectomy on the motion behavior of whole lumbar spine are investigated using a Selspot II system. Fresh human ligamentous specimens were potted at the sacrum and clinically relevant loads (flexion/extension, right/left lateral bending, and right/left axial torsion moments) applied through a loading frame attached rigidly to the topmost vertebra of the specimen. The resulting three-dimensional motions of each vertebra for the intact specimen were recorded. The specimen was injured sequentially on the right side of the L4-5 level: partial laminectomy, partial facetectomy, subtotal discectomy, and total discectomy. The motion behavior of the specimen after each injury was recorded. The results of the injured tests were normalized with respect to the corresponding intact results. The normalized data for eight specimens were pooled for statistical analysis. Subtotal discectomy induced significantly less motion at the injury site than total discectomy, in all loading modes. At L3-4, the motion segment above the injury level, anteroposterior translation in flexion and lateral translation in left lateral bending show significant increases irrespective of the amount of nucleus excised. The clinical relevance of these findings are discussed.     

Changes in posterior disc bulging and intervertebral foraminal size associated with flexion-extension movement: a comparison between L4-5 and L5-S1 levels in normal subjects.

BACKGROUND CONTEXT: No previous study has used magnetic resonance imaging (MRI) to evaluate changes of posterior disc bulging and intervertebral foraminal size in the normal spine with flexion-extension movement, comparing L4-5 versus L5-S1 intervertebral levels. PURPOSE: To determine changes in posterior disc bulging and intervertebral foraminal size with flexion-extension movement, comparing L4-5 versus L5-S1 intervertebral levels. STUDY DESIGN: An in vivo study of magnetic resonance kinematics with spine flexion extension. METHODS: Spines of three volunteers with no history of low back pain were scanned in neutral, flexion, and extension positions in a vertically open MRI system. MRI was repeated after 6 hours of normal activity and an additional 4 hours of heavy activity with a weighted vest. Posterior bulging of the intervertebral disc and the size of intervertebral foramen were measured at the L4-5 and L5-S1 levels. RESULTS: With spine flexion, posterior bulging of the discs increased at L4-5 in eight of nine measurements (three different spine-loading states for each of three subjects) and L5-S1 discs in six of nine measurements. In most cases, posterior bulging decreased with extension. No significant difference was noted in the degree of disc bulge between levels. Foraminal size at L4-5 increased with flexion and decreased with extension, and the extent of these changes was greater at the L4-5 level than at L5-S1. CONCLUSIONS: This pilot study demonstrates two distinct behavior characteristics of the normal spine with flexion-extension movement.     

Distribution of in vivo and in vitro range of motion following 1-level arthroplasty with the CHARITE artificial disc compared with fusion

OBJECT: One of the goals of lumbar arthroplasty is to restore and maintain range of motion (ROM) and to protect adjacent levels from abnormal motion, which may be a factor in transition syndrome following arthrodesis. In this study, in vitro ROM results were compared with in vivo, 2-year postoperative radiographic ROM evaluations. METHODS: Radiographs of patients enrolled in the CHARITE investigational device exemption study were analyzed at baseline and at 2 years postoperatively. The ROM in flexion/extension at the implanted and adjacent levels was measured, normalized, and compared with ROM results obtained using cadaver (in vitro) evaluations. RESULTS: Preoperative ROM distributions in patients enrolled for arthroplasty or fusion at the L4-5 level was as follows: 28% motion was observed at L3-4, 35% at L4-5 and 37% at L5-S1. Following a one-level arthroplasty at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 36% at L3-4, 30% at L4-5 and 35% at L5-S1. Following a one-level fusion with BAK and pedicle screws at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 45% at L3-4, 9% at L4-5 and 46% at L5-S1. CONCLUSIONS: The baseline as well as the 2-year in vivo data confirmed previously published in vitro data. One-level arthroplasty was shown herein to replicate the normal distribution of motion of the intact spine.     

Biomechanics of two-level Charité artificial disc placement in comparison to fusion plus single-level disc placement combination.

BACKGROUND CONTEXT: Biomechanical studies of artificial discs that quantify parameters such as load sharing and stresses have been reported in literature for single-level disc placements. However, literature on the effects of using the Charité artificial disc (ChD) at two levels (2LChD) as compared with one-level fusion (using a cage [CG] and a pedicle screw system) plus one-level artificial disc combination (CGChD) is sparse. PURPOSE: To determine the effects of the 2LChD and CGChD across the implanted and adjacent segments. STUDY DESIGN: A finite element model of a L3-S1 segment was used to compare the biomechanical effects of the ChD placed at two lower levels (2LChD model) with L5-S1 fusion (using a CG and a pedicle screw system) plus L4-L5 level ChD placement combination (CGChD model). METHODS: We used our recently published and experimentally validated L3-S1 finite element model for the present study. The intact model was subjected to 400 N axial compression and 10.6 Nm of flexion/extension moments. The experimental constructs described above were then subjected to 400 N axial compression and a moment that produced overall motion equal to the intact model predictions (hybrid testing protocol). Resultant motion, loads across facets, and other parameters were analyzed at the experimental and adjacent levels. RESULTS: In flexion, the bending moments for the CGChD and 2LChD models were 15.4 Nm (fusion effect) and 7.3 Nm (increase in flexibility effect), respectively in comparison to 10.6 Nm for the intact model. The corresponding values in the extension mode were 11.2 Nm and 7.2 Nm. The predicted flexion rotations across the L5-S1 segment for the CGChD decreased by 76% (fusion effect), and increased at the L4-L5 and the L3-L4 levels by 68.5% and 28%, respectively. In the extension mode, motion across the L5-S1 segment decreased by 96.4% whereas it increased 74.6% and 18.2% across the L4-L5 and L3-L4 levels, respectively. For the 2LChD model, the flexion rotation across the L5-S1 segment increased by 28.2%. The motions across the L4-L5 and L3-L4 segments decreased by 12% and 24%, respectively. In extension, the corresponding changes were 10% increase, 10% increase, and 21% decrease at the L5-S1, L4-L5, and L3-L4 levels, respectively. The facet loads were in line with the changes in motion, except for the 2LChD case. CONCLUSIONS: The changes at L3-L4 level for both of the cases were of similar magnitude (approximately 25%), although in the CGChD model it increased and in the 2LChD model it decreased. The changes in motion at the L4-L5 level were large for the CGChD model as compared with the 2LChD model predictions (approximately 70% increase vs. 10% increase). It is difficult to speculate if an increase in motion across a segment, as compared with the intact case, is more harmful than a decrease in motion.     

Radiographic analysis of lumbar motion in relation to lumbosacral stability. Investigation of moderate and maximum motion

STUDY DESIGN: This in vivo study was performed to examine active lumbar motion without any support. OBJECTIVES: To establish the behavior of segmental flexibility according to the degree of whole lumbar motion and to clarify the correlation between bony characteristics of the lumbosacral junction and stability in the segment. SUMMARY OF BACKGROUND DATA: In previous studies, the full mobility of the lumbar segments has been investigated. The details of motion commonly seen with the activities of daily living have not been clarified. It has been reported that the iliolumbar ligaments have an influence on lumbosacral stability and that the relative thickness of the transverse process of L5 could indicate the functional strength of the iliolumbar ligaments. However, the effects of the iliolumbar ligaments on the lumbosacral range of motion have not been studied in vivo. METHODS: Ninety adults, aged 20-39 years, were requested to perform motion commonly associated with activities of daily living, defined as moderate motions of the lumbar spine. The subjects then were asked to perform maximal motion of the lumbar spine. The segmental ranges of motion, segmental flexion, and extension at every level of the lumbar spine were calculated by using functional radiographs. The correlation between the relative thickness of the transverse process of L5 and the motion seen at the lumbosacral junction was also determined. RESULTS: The greatest segmental range of motion was found at L2-L3 in moderate motion and at L4-L5 in maximal motion. It shifted gradually from the upper to lower lumbar levels with the increase in total lumbar motion. With an increase in lumbar spine motion, maximum segmental flexion shifted from L2-L3 to L3-L4, then to L4-L5. Segmental extension changed only at L5-S1, increasing with total lumbar spine motion. There was an inverse statistical correlation between lumbosacral motion and relative thickness of the L5 transverse process. CONCLUSIONS: The greatest segmental flexibility induced by the moderate lumbar motion, usually seen with the activities of daily living, occurred more in the upper segments of the lumbar spine, especially in flexion. Further, the iliolumbar ligaments regulate lumbosacral motion especially flexion.     

Transdiscal L5-S1 screws for the fixation of isthmic spondylolisthesis: a biomechanical evaluation

The current study is a biomechanical study using a cadaveric model of L5-S1 spondylolisthesis. The purpose of the current study was to compare, in a cadaveric model of simulated L5-S1 spondylolisthesis, the biomechanical stiffness of transdiscal fixation with traditional pedicle screw fixation, and transdiscal fixation with combined interbody/pedicle screw fixation. The surgical management of L5-S1 spondylolisthesis is a challenge because of the difficulties in achieving a reliable arthrodesis in the face of high mechanical forces. A method of lumbosacral fixation that has been used successfully in moderate grades of spondylolisthesis at our institution involves the use of transdiscal S1 pedicle screws. With this technique, S1 pedicle screws are placed through the S1 pedicle, through the superior endplate of S1, through the inferior endplate of L5, to terminate in the L5 body. Eighteen fresh human cadaveric (age 59-88 years) L5-S1 motion segments were obtained. The end of each intact motion segment was potted up to its midbody in a 10-cm-diameter polyvinylchloride end-cap using dental cement. The intact specimen was then biomechanically tested as follows: 1) axial compression (500 N), 2) flexion (10 Nm), 3) extension (10 Nm), 4) right lateral bending (10 Nm), and 5) left lateral bending (10 Nm). Stiffness values were calculated from the load-deflection curves obtained. Spondylolisthesis was then simulated by displacing L5 on S1 (% slip average = 41.3%) after performing a radical L5-S1 discectomy, L5 laminectomy, and bilateral L5-S1 facetectomies. The 18 motion segments were divided into two groups. Group I (n = 10) was biomechanically tested (as above) after pedicle screw fixation and again after replacing the S1 pedicle screws with transdiscal screws. Group II (n = 8) was biomechanically tested (as above) after combined interbody/pedicle screw fixation and again after fixation with transdiscal screws. Load-deflection curves were obtained each time, and stiffness values were calculated from the curves. Transdiscal fixation was 1.6-1.8 times stiffer than pedicle screw fixation (p < 0.05) in all loading modes tested. There were no differences in stiffness between transdiscal fixation and combined interbody/pedicle screw fixation. In a cadaveric model of simulated L5-S1 spondylolisthesis, transdiscal L5-S1 fixation produced a 1.6-1.8 times stiffer construct than traditional pedicle screw fixation. Further, the stiffness of the transdiscal fixation was equal to that of a combined interbody/pedicle screw fixation.     

The effect of injury on rotational coupling at the lumbosacral joint. A biomechanical investigation.

The lumbosacral joint is frequently indicated as a source of low-back pain, a cause of which may be abnormal patterns of vertebral motions. The goal of this study was to describe the influence of injury on the coupled motions of the L5-S1 joint in a human cadaveric model. Nine whole lumbosacral spine specimens were studied under the application of flexion, extension, left/right axial torque and right/left lateral bending pure moments. Injuries to the posterior ligaments, intervertebral disc, and articular facets at L5-S1 were produced, and the motion at L5-S1 was determined after each sequential injury. No significant coupled rotations were observed under flexion or extension moments. Under axial torque, lateral rotation at L5-S1 occurred to the same side as the applied torque and increased significantly only after injury to the intervertebral disc. Also coupled to axial torque was flexion rotation in the intact specimen, which became extension rotation after facetectomy. Under lateral bending moments, coupled axial rotation was to the opposite side of the applied moment and increased significantly only after removal of the facets of L5. Based on these results, it was concluded that intervertebral disc most resisted the coupled motion of lateral rotation under the application of axial torque, whereas the articular facets most resisted the coupled axial rotation under the application of lateral bending at the lumbosacral joint. Also, the facets were the structures that produced the flexion rotation of L5 on S1 under axial torque loading.     

Effects of specimen length on the monosegmental motion behavior of the lumbar spine

STUDY DESIGN: An in vitro biomechanical analysis of the segmental motion behavior of the same segments in polysegmental (five segments), bisegmental, and monosegmental specimens using sheep lumbosacral spines. OBJECTIVES: To investigate the effect of specimen length on monosegmental motion behavior. These data may be helpful in planning in vitro tests and in comparing results of studies using specimens of different lengths. SUMMARY OF BACKGROUND DATA: The length of spinal specimens used for in vitro stability tests varies greatly, depending on the purpose of the study. Some investigators prefer testing specimens with one adjacent segment on either end of the region of interest. Others favor specimens as short as possible. METHODS: In a first step, seven sheep spine specimens, L3-S1 (note that sheep spines normally have seven lumbar vertebrae), each were tested without preload in a spine-loading apparatus. Alternating sequences of pure lateral bending, flexion/extension, and axial rotation moments (+/-3.75 Nm) were applied continuously. The motion in each single segment was measured simultaneously. Then, these polysegmental specimens were cut into two bisegmental specimens, L3-L5 and L6-S1, and tested in the same way. Finally, another vertebra was removed to obtain two monosegmental specimens, L3-L4 and L7-S1, and to test them as described. RESULTS: In general, the range of motion at L3-L4 and L7-S1 was smaller when tested in polysegmental than in monosegmental specimens. In polysegmental specimens (five segments), the range of motion at L3-L4 and L7-S1 was approximately 80% (range, 70.6-92.5%) and in bisegmental specimens approximately 95% (range, 66.7-100%) of their range of motion measured in monosegmental specimens. Neutral zone and coupled motions showed the inverse behavior. Significant differences were found. However, they were not consistent with either the loading direction or with the specimen length. CONCLUSIONS: For comparison of results, the specimen length should be kept constant within one experiment. Segmental motion behavior of specimens with different lengths should be compared only qualitatively.