Kinematics of the thoracic spine in trunk lateral bending: in vivo three-dimensional analysis

Background contextIn vivo three-dimensional kinematics of the thoracic spine in trunk lateral bending with an intact rib cage and soft tissues has not been well documented. There is no quantitative data in the literature for lateral bending in consecutive thoracic spinal segments, and there has not been consensus on the patterns of coupled motion with lateral bending.PurposeTo demonstrate segmental ranges of motion (ROMs) in lateral bending and coupled motions of the thoracic spine.Study designIn vivo three-dimensional biomechanics study of the thoracic spine.Patient sampleFifteen healthy male volunteers.Outcome measuresComputed analysis by using voxel-based registration.MethodsParticipants underwent computed tomography of the thoracic spine in three supine positions: neutral, right maximum lateral bending, and left maximum lateral bending. The relative motions of vertebrae were calculated by automatically superimposing an image of vertebrae in a neutral position over images in bending positions, using voxel-based registration. Mean values of lateral bending were compared among the upper (T1–T2 to T3–T4), the middle-upper (T4–T5 to T6–T7), the middle-lower (T7–T8 to T9–T10), and the lower (T10–T11 to T12–L1) parts of the spine.ResultsAt lateral bending, the mean ROM (±standard deviation) of T1 with respect to L1 was 15.6°±6.3° for lateral bending and 6.2°±4.8° for coupled axial rotation in the same direction as lateral bending. The mean lateral bending of each spinal segment with respect to the inferior adjacent vertebra was 1.4°±1.3° at T1–T2, 1.3°±1.2° at T2–T3, 1.4°±1.3° at T3–T4, 0.9°±0.9° at T4–T5, 0.8°±1.0° at T5–T6, 1.1°±1.1° at T6–T7, 1.7°±1.2° at T7–T8, 1.3°±1.2° at T8–T9, 1.6°±0.7° at T9–T10, 1.8°±0.8° at T10–T11, 2.3°±1.0° at T11–T12, and 2.2°±0.8° at T12–L1. The smallest and the largest amounts of lateral bending were observed in the middle-upper and the lower parts, respectively. There was no significant difference in lateral bending between the upper and the middle-lower parts. Coupled axial rotation of each segment was generally observed in the same direction as lateral bending. However, high variability was found at the T2–T3 to T5–T6 segments. Coupled flexion was observed at the upper and middle parts, and coupled extension was observed at the lower part.ConclusionsThis study revealed in vivo three-dimensional motions of consecutive thoracic spinal segments in trunk lateral bending. The thoracolumbar segments significantly contributed to lateral bending. Coupled axial rotation generally occurred in the same direction with lateral bending. However, more variability was observed in the direction of coupled axial rotation at T2–T3 to T5–T6 segments in the supine position. These results are useful for understanding normal kinematics of the thoracic spine.     

Rip hump correction and rotation of the lumbar spine after selective thoracic fusion

In this study a series of 32 patients with idiopathic scoliosis, managed with selective thoracic fusion, was reviewed. Classified according to King and instrumented with the H-frame, the patients were evaluated for curve correction, rib hump correction and postoperative shift in lumbar rotation. Age and follow-up averaged 19.4 and 2.4 years, respectively. The 32 patients had an average primary and lumbar curve correction of, respectively, 66% (6.0% correction loss) and 53% (3.4% correction loss). The respective values for postoperative rib hump correction and shift in apical lumbar rotation averaged 8° and 9.4° in type II King curves, 4.4° and 3.5° in type III and 11° and-5° in Type IV. Significant differences were noted between the curve types in rib hump correction and shift in lumbar rotation. The study showed that en bloc postoperative rotation of the compensatory lumbar segment, directed towards the rib hump, positively influences rib hump correction. This en bloc rotation of the unfused lumbar segments is induced by the correcting forces applied by the instrumentation. The unfused lumbar spine of a patient with a King type II curve shows a larger lumbar rotation shift and subsequent rib hump correction than that of a patient with a King type III curve. Together with factors such as lateral angulation, rib-vertebra angles and structural limitations, the rotational dynamics of the unfused lumbar spine seem to form an important component in the understanding and surgical management of scoliosis.     

Kinematics of the lumbar spine in trunk rotation: in vivo three-dimensional analysis using magnetic resonance imaging

In vivo three-dimensional (3D) kinematics of the lumbar spine has not been well evaluated by the conventional methods because of their methodological limitations, while 3D intervertebral motions have been quantitatively determined by cadaver studies. We thus developed a novel 3D analyzing system for the relative motions of individual vertebrae using 3D magnetic resonance imaging (MRI) and analyzed in vivo 3D intervertebral motions of the lumbar spine during trunk rotation. Ten healthy volunteers underwent 3D MRI of the lumbar spine in nine positions with 15° increments during trunk rotation (0°, 15°, 30°, 45°, and maximum). Relative motions of the lumbar spine were calculated by automatically superimposing a segmented 3D MRI of the vertebra in the neutral position over images of each position using the voxel-based registration method. These 3D motions were represented with 6 degrees of freedom by Euler angles and translations on the coordinate system. The mean axial rotation of ten healthy volunteers of each lumbar spinal segment in 45° trunk rotation to each side ranged from 1.2° to 1.7°. Coupled flexion with axial rotation was observed at the segments from L1/2 to L5/S1. Coupled lateral bending of the segments from L1/2 to L4/5 was in the opposite direction of the trunk rotation, while that of T12/L1 and L5/S1 was in the same direction. The direction of the coupled lateral bending in the present study was different from that in the previous cadaver study only at L4/5. This difference might result from the non-load state of the supine position in the current study and/or the non-physiological state in the cadaver study. Our system has two limitations: (1) the study was conducted with each volunteer in the supine position, and (2) because the rotation device regulated trunk rotation, trunk rotation might not have been physiological. In vivo 3D intervertebral motions of the lumbar spine during trunk rotation were evaluated using our novel motion analysis system. These data may be useful for the optimal orthopaedic management of lumbar spinal disorders. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of increased axial rotation angle on bone mineral density measurements of the lumbar spine

Background contextOsteoporosis frequently occurs in elderly people and is commonly associated with neuromuscular diseases or severe cerebral palsy. Osteoporosis can cause pain via compression fractures or secondary neurologic deficits; thus, accurate evaluation of bone mineral density (BMD) is essential for the prevention and treatment of osteoporosis. However, spinal axial rotation caused by scoliosis may affect the outcome of BMD tests, such that BMD measurements may be significantly greater than actual BMD in patients with severe scoliosis of the spine.PurposeWe investigated the effect of axial rotation angle on BMD measurements of the phantom spine.Study design/settingInvestigation for the effect of axial rotation with aluminum phantom spine.MethodsA GE-Lunar Aluminum Spine Phantom was used to assess BMD. Bone mineral content (BMC), BMD, and cross-sectional area were measured 100 times at L1–L4 using a GE Lunar Prodigy Vision system. Dual-energy X-ray absorptiometry was performed at axial rotation angles of 0° to 25° (5° intervals).ResultsCross-sectional area decreased and BMD values increased as the axial rotation angle increased, whereas BMC did not change significantly. A fitting function was obtained to evaluate the relationships among axial rotation angle, cross-sectional area, and BMD. We obtained an equation to estimate BMD at L1–L4: 1.000?0.001674x+0.0001043x²?0.000005333x³, where x denotes the axial rotation angle. We found that the observed BMD needed adjustment when the angle was more than 5°.ConclusionsBone mineral density values may be overestimated in patients with even slight (>5°) axial rotation. When osteoporosis is suspected in a clinical setting, the degree of axial rotation should be measured on a lumbar spine X-ray.     

Lenke 1AL型青少年特发性脊柱侧凸腰椎代偿弯中顶椎旋转度的影响因素分析

[目的]通过分析Lenke 1型AIS患者冠状位及矢状位的术前影像学资料,探讨影响代偿性腰弯顶椎旋转畸形的影像学参数.[方法]回顾性分析2004～2011年58例以右胸弯为主弯的Lenke 1AL型AIS患者术前站立正、侧位X线像,测量冠状面及矢状面Cobb角,L4椎体倾斜度,骨盆旋转度,胸弯与腰弯的顶椎旋转度及腰弯顶椎节段所在节段等指标并进行相关分析.[结果]腰弯顶椎旋转度与冠状位腰弯Cobb角度(P＜0.001),胸弯Cobb角度(P=0.012),L4椎体倾斜度(P ＜0.001)及骨盆旋转度(P=0.003)存在明显的相关关系,而控制腰弯Cobb角后胸弯顶椎旋转度(P=0.014)代替了胸弯Cobb角的相关性.[结论]Lenke 1AL型AIS代偿性腰弯顶椎旋转度受到冠状面及上下节段水平面轴向旋转畸形的影响,而与矢状面之间的关系无统计学意义.     

自控腰椎纵轴加压器诊断隐匿性腰椎退行性变

目的探讨自控腰椎纵轴加压器对隐匿性腰椎退行性变的诊断价值。方法采用自制"自控腰椎纵轴加压器"对120例腰腿痛(98例坐骨神经痛、22例腰痛)患者行腰椎纵轴加压CT/MR检查,所加压力不超过患者体质量的50%,并与常规腰椎CT/MR检查进行比较,硬膜囊面积减小(>15mm2)并降至75mm2以下、侧隐窝狭窄、椎间盘突出或程度增加等异常征像为腰椎纵轴加压检查的附加有效信息(AVI)。结果 120例中43例存在AVI,包括硬膜囊面积减小33例,椎间盘突出11例和突出程度增加15例,侧隐窝或椎间孔狭窄12例。98例坐骨神经痛患者中40例(40/98,40.82%)出现AVI,22例腰痛患者中仅3例(3/22,13.64%)出现AVI(P<0.05)。结论腰椎纵轴加压CT/MR检查对显示腰椎及椎管的隐匿性退行性变具有重要临床价值。     

Rasterstereographic analysis of axial back surface rotation in standing versus forward bending posture in idiopathic scoliosis

The forward bending test according to Adams and rib hump quantification by scoliometer are common clinical examination techniques in idiopathic scoliosis, although precise data about the change of axial surface rotation in forward bending posture are not available. In a pilot study the influence of leg length inequalities on the back shape of five normal subjects was clarified. Then 91 patients with idiopathic scoliosis with Cobb-angles between 20° and 82° were examined by rasterstereography, a 3D back surface analysis system. The axial back surface rotation in standing posture was compared with that in forward bending posture and additionally with a scoliometer measurement in forward bending posture. The changes of back shape in forward bending posture were correlated with the Cobb-angle, the level of the apex of the scoliotic primary curve and the age of the patient. Averaged over all patients, the back surface rotation amplitude increased from 23.1° in standing to 26.3° in forward bending posture. The standard deviation of this difference was high (6.1°). The correlation of back surface rotation amplitude in standing with that in forward bending posture was poor (R ²=0.41) as was the correlation of back surface rotation in standing posture with the scoliometer in forward bending posture measured rotation (R ²=0.35). No significant correlation could be found between the change of back shape in forward bending and the degree of deformity (R ²=0.07), likewise no correlation with the height of the apex of the scoliosis (R ²=0.005) and the age of the patient (R ²=0.001). Before forward bending test leg length inequalities have to be compensated accurately. Compared to the standing posture, forward bending changes back surface rotation. However, this change varies greatly between patients, and is independent of the type and degree of scoliosis. Furthermore remarkable differences were found between scoliometer measurement of the rib hump and rasterstereographic measurement of the vertebral rotation. Therefore the forward bending test and the identification of idiopathic scoliosis rotation by scoliometer can be markedly different compared to rasterstereographic surface measurement in the standing posture.     

Abnormalities of the lumbar spine in the coronal plane on plain abdominal radiographs

The main objective of this study is to determine the prevalence of coronal abnormalities of the lumbar spine in a large population of patients with respect to their age and sex. Lumbar degenerative disease is associated with degenerative scoliosis. Degenerative scoliosis and lateral listhesis are important features to identify before decompressive surgery as deformity may not be seen on magnetic resonance imaging scans. Scoliosis and lateral listhesis may be important in the development of symptoms especially in an ageing population. All abdominal and plain kidney–ureter–bladder radiographs performed over a 10-month period were reviewed. 2,765 radiographs were assessed for scoliosis (Cobb angle greater then 10°), lateral listhesis and evidence of osteoarthritis. The prevalence of scoliosis, lateral listhesis and osteoarthritis of the lumbar spine increased with age. Scoliosis and lateral listhesis were significantly more prevalent in women. Deformity starts to occur after the age of 50 and steadily increases with age. By the ninth decade nearly a quarter of patients have evidence of scoliosis and lateral listhesis. As the adult lumbar spine ages, the prevalence of lateral listhesis and degenerative scoliosis increases. It is important to appreciate these coronal abnormalities in patients undergoing decompressive surgery for spinal stenosis. This increase in deformity may have a greater impact as the population continues to age.     

Motion in lumbar functional spine units during side bending and axial rotation moments depending on the degree of degeneration

STUDY DESIGN: Human lumbar spine specimens were tested in axial rotation and side bending. Motion was related to the grade of degeneration. OBJECTIVES: To determine the degree to which degeneration with fissure formation in the disc affects axial rotation of the lumbar functional spine unit. SUMMARY OF BACKGROUND DATA: There is controversy in the literature regarding the influence of severe degeneration and fissures of the disc on the range of axial rotation. METHODS: Thirty-six lumbar spine specimens were tested in axial rotation and side bending, by applying pure moments in an unconstrained setting. The motion in 6 df was recorded by dial gauges. The grade of degeneration was established by the grading schemes of Nachemson, Thompson, Adams, and Mimura. RESULTS: A significant increase of axial rotation and lateral translation under torque was found. This increase mainly took place between Grade 3 according to the schemes of Nachemson, Thompson, and Adams (no fissure formation) and the higher grades of degeneration (defined by fissure formation). Reduced disc height was always associated with fissures. CONCLUSIONS: A reduced lumbar disc height in radiographs seems to be associated with fissure formation in the disc. In this case, the range axial rotation after torque is increased in comparison with cases with less degeneration.     

Placement of pedicle screws using three-dimensional fluoroscopy-based navigation in lumbar vertebrae with axial rotation

Despite potential advantages of three-dimensional fluoroscopy-based navigation, there still remain a lot of controversies about the indications of this technology, especially whether it is worthy of being used in placement of pedicle screws in lumbar spine. However, according to the inconsistent conclusions reported in the literature and our experiences, the traditional method relying on anatomical landmarks and fluoroscopic views to guide lumbar pedicle screw insertion is unable to meet the requirement of precise screw placement. Based on our observation, screw malposition seems to occur concomitant with vertebral axial rotation which is a ubiquitous phenomenon. Three-dimensional fluoroscopy-based navigation can provide the most valuable axial images in real-time, so it may be useful for placement of pedicle screws in lumbar spine. This study was intended to evaluate the effect of axial rotation of lumbar vertebrae on the accuracy of pedicle screw placement using the traditional method, as well as assess the value of three-dimensional fluoroscopy-based navigation in improving the accuracy. Sixteen lumbar simulation models at different degrees of axial rotation (0°, 5°, 10°, and 20°), with every four assigned the same degree, were equally divided into two groups (traditional method group and three-dimensional fluoroscopy-based navigation group). Random placement of pedicle screws was carried out, followed by CT scan postoperatively. Then the outer pedicle cortex contours were depicted from reconstructed sectional pedicle images using Photoshop. The accuracy of pedicle screw placement was evaluated by determining the interrelationship between screw trajectory and pedicle cortex (quality), and measuring the shortest distance from pedicle screw axis to outer cortex of the pedicle (quantity). Eighty pedicle screws were implanted, respectively, in each group. In traditional method group, statistical difference existed in the accuracy of pedicle screw placement at different axial rotational degrees (P < 0.05). With degrees increasing, the accuracy declined. The accuracy of three-dimensional fluoroscopy-based navigation group was higher than traditional method group in vertebrae with axial rotation (P < 0.01). In qualitative evaluation, the accuracy of the two methods had statistical difference when the degree was 20°, and in quantitative evaluation, statistical difference existed in 5°, 10°, and 20° of vertebral axial rotation.     

经椎间孔入路腰椎体间融合治疗下腰椎退变

目的总结经椎间孔入路腰椎体间融合治疗下腰椎退变的临床效果。方法采用半椎板或全椎板切除、经椎间孔入路腰椎体间融合、椎弓根螺钉固定治疗下腰椎退变患者26例。结果26例随访4~28个月,平均11个月。临床评价:优13例,良12例,尚可1例。无1例出现永久性神经损伤手术并发症。术后X线片显示植骨密度随术后时间的延长而加深,钛网融合器无下陷,椎间隙高度无丢失,椎弓根螺钉系统无断裂和移位。结论经椎间孔入路腰椎体间融合治疗下腰椎退变创伤小,并发症少,临床效果较好。     

坐位下腰椎前屈后伸时轴向载荷对下腰椎在体运动的影响

【摘要】 目的：研究坐位下轴向载荷对腰椎前屈后伸时下腰椎节段运动的影响。方法：招募10名志愿者进行研究,其中男性5例,女性5例,年龄31（26,34）岁,体质指数（body mass index,BMI）22.5（22.0,23.4）kg/m2。用CT扫描获取受试者仰卧位时L3~S椎体的影像并进行三维重建。在双透视成像系统中采集受试者坐位L3~S1在中立、最大前屈及最大后伸姿势时的瞬时影像。在Rhinoceros软件环境中将不同坐位姿势的瞬时影像与三维模型配准。测量由仰卧位变化为中立坐位时椎体的相对位移距离和相对旋转角度;在生理条件下和额外轴向载荷（背负10kg特制背心）的坐位下,比较两种状态下最大前屈到最大后伸运动中椎体的活动度（range of motion,ROM）,由中立坐位到最大前屈、后伸坐位姿势时腰椎活动度的差异。结果：生理坐位下,由仰卧位变成中立坐位,L5相对于S1向背侧位移1.4（0.6,2.4）mm,前屈旋转11.4°（10.2°,17.9°）,L3/4、L4/5在矢状面上旋转0.8°（-2.1°,3.8°）、4.4°（-1.0°,8.9°）,旋转幅度较L5/S1无显著性差异（P>0.05）;在前屈后伸过程中,L3~S1各节段在左右方向位移分别为2.0（1.6,2.5）mm、1.8（1.0,2.4）mm、5.9（3.7,6.4）mm;近远端方向位移分别为1.0（0.7,1.2）mm、0.7（0.6,1.3）mm、3.3（1.7,4.0）mm,L5/S1在左右方向及近远端方向的位移较L3/4、L4/5有显著性差异（P<0.05）;在由中立坐位到最大后伸坐位运动过程中,L3~S1各节段在左右方向上的位移分别为0.7（0.3,1.4）mm、0.5（0.3,0.6）mm、2.6（1.3,3.8）mm;在矢状面上的旋转角度分别为4.2°（1.1°,5.6°）、2.2°（1.4°,3.3°）、9.5°（4.6°,12.2°）。加载额外轴向载荷后,与生理坐位相比,由仰卧位变成中立坐位,L5/S1在矢状面上旋转减小1.2°、在头尾方向上压缩1.5mm;前屈后伸运动中,L5/S1在前后、左右及近远端方向的位移分别减少2.8、4.1、1.3mm;中立到最大后伸坐位运动过程中,L5/S1的旋转范围减小6.1°（P=0.038）。结论：由仰卧位转换为中立坐位,下腰椎偏向前屈位置。生理坐位前屈后伸运动中,L5/S1有较大的活动度。伴随着额外轴向载荷的加载,L5/S1活动度减少。相比较于L5/S1,有或无加载额外轴向载荷对L3/4、L4/5在坐位前屈后伸中运动学参数影响较小。     

Thoracic spine centers of rotation in the sagittal plane

The purpose of this study was to determine in vitro the centers of rotation of thoracic functional spinal units in the sagittal plane. The center of rotation is a convenient concept and part of a precise method of documenting the kinematics of a joint moving in a plane. Fresh cadaver functional spinal units from the thoracic region were utilized. Six load types were used that produced motions only in the sagittal plane, namely anterior and posterior shear forces, flexion and extension moments, and compression and distraction forces. The resulting motion with three degrees of freedom was measured with dial gauges. Statistical methods were used to analyze data from the viewpoint of vertebral level, load magnitude, and load type. Only the load type was found to be significantly related to the location of the centers of rotation. Although there was significant variability in the centers of rotation, there were definite locations related to each load type. The average center of rotation was 15–45 mm directly below the geometric center of the moving vertebra. The results of the present study may be helpful in the clinical interpretation of spinal kinematic studies.     

一种新型腰椎动态固定系统的初步生物力学分析

目的设计一种后路腰椎椎弓根动态固定系统,并对其进行生物力学试验,从而为其临床应用提供一定可行性依据。方法选取新鲜小牛腰椎(L2~5),将标本分成4组:A组(正常试验组)、B组(腰椎减压非固定组)、C组(动态系统固定组)、D组(传统坚强钉棒系统固定组),5个标本按一定顺序依次在指定力学测试机器上进行生物力学试验,测定给定载荷下(500、1 000、2 000、3 000、4 000、5 000 N)小牛腰椎标本的形变量,并对相关数据进行统计学分析。结果首先对500 N载荷下的形变量进行统计学分析,500 N载荷下各组样本所在总体的方差齐(Levene值为1.923,P=0.1690.05),ANOVA分析结果显示500 N的负荷下各组形变量不全相同(F=90.251,P0.05),SNK法分析结果显示4组中任意2组之间的差异有统计学意义(P0.05)。测量结果显示在给定压力下B组标本形变量值均大于A组,C、D组标本的形变量值均大于A、B组,C组形变量均大于D组对应值,差异有统计学意义(P0.05)。对4组在1 000 N、2 000 N、3 000 N、4 000 N、5 000 N载荷下也做了同样的比较分析,得到类似的结果。结论新设计的动态固定系统分散了应力的集中,稳定了腰椎,一定程度保留了固定腰椎节段的运动,承载了部分固定邻近节段的负荷,固定有效。     

In vivo study of the kinematics in axial rotation of the lumbar spine after total intervertebral disc replacement: long-term results: a 10–14 years follow up evaluation

Introduction: We did not find any in vivo study of spinal segment kinematics after disc replacement, especially over the long term. In vitro studies did show that it restores almost normal kinematics except for axial rotation. The goal of this study is to develop a new technique in order to analyse axial rotation of a spinal segment, in vivo, after total disc replacement. Materials and methods: A comparative retrospective study of motion in axial rotation at L4L5 level was carried out on 17 patients with artificial discs versus six healthy volunteers. Five patients carried one prostheses at L4L5 level and 12 carried two prosthesis at L4L5 and L5S1 levels. The follow up ranged from 10.8 to 14.3 years (average 12.4±1, median 12.6). Dynamic radiographs in axial rotation were made using a special protocol. A new technique associating a stereographic method and image processing software was developed in order to evaluate the range of motion in axial rotation as well as the mechanical coupling. Results: The standard deviation of angular measurements was 1.8°. Eleven (65%) patients had a normal mobility in torsion, identical to those of the volunteers and of the literature, whereas six (35%) had an abnormal increased mobility. If only one disc was replaced, mobility in torsion was identical to that of the volunteers, in the case of two replaced discs, 50% (6/12) of the patients had an abnormal increased mobility. In the sub-group of normal mobility, the coupling was identical to that of the volunteers. In the sub-group of increased mobility, the coupling was different with a strong flexion (10°), increased by about 7° (P<0.001). Conclusion: The implementation of only one discal prosthesis SB Charité seems to restore kinematics close to that of the healthy volunteers and comparable to the literature. The implementation of two adjacent prostheses does not restore normal kinematics in 50% of the cases. It is probable that the existence of active stabilizing elements explains the difference with the in vitro studies carried out beforehand.     

Neurological deficit in injuries of the thoracic and lumbar spine

Summary Seventy consecutive patients with injuries of the thoracic and lumbar spine accompanied by neurological deficit were prospectively studied and followed-up.In 40 of these patients with a burst fracture, the degree of involvement of the cross-sectional area of the spinal canal, as revealed on first CT after admission, was not correlated with the type and degree of initial neurological deficit.In patients with injuries of the lumbar spine, neurological deficit may be mild, although the sagittal diameter of the spinal canal may be reduced by as much as 90%.We cannot establish a difference in neurological recovery between those cases who were managed conservatively and those in whom a surgical decompression and stabilization procedure was performed.Surgical stabilizing procedures, however, result in immediate stabilization of the spine, they diminish pain, facilitate nursing care and allow more rapid mobilization and earlier active rehabilitation.If major extraspinal injuries form a relative contra-indication to surgical decompression of the cord and stabilization of the spine injury, the patient can quite well be treated conservatively without endangering neurological recovery.     

Transpedicular screw fixation of the lumbar spine: “How I Do It”

The technique of lumbar vertebral body screw insertion is described in detail. The exposure, starting point determination, and direction of insertion are all discussed. The specifics of the use of the joystick or gear shift followed by the nuances of the insertion of the screw itself are detailed.     

退行性腰椎侧凸合并冠状位整体失平衡矫形方式的初步研究

目的 :探索伴腰骶段畸形的退行性侧凸畸形的手术策略,以实现其冠状位失平衡的术中良好矫正,进而达到术后即刻的整体冠状位平衡。方法:2018年5月～2018年9月,对收治的5例伴腰骶段畸形的退变性脊柱侧凸患者行矫形手术。以患者术中俯卧位足跟连线中点、臀沟、C7棘突三个标记点作为矫形参考,腰段及腰骶段顶椎凹凸双侧充分松解,首先矫正主弯,而后利用体位垫复位作用,配合内固定整体把持矫形力,进行腰骶段畸形的矫正,实现三标记点共线。测量患者矫形前后站立位脊柱全长X线片的冠、矢状位脊柱骨盆参数,并进行比较。结果:5例患者均顺利完成手术,未发生严重并发症。患者术前冠状位失平衡距离、腰段主弯Cobb角、腰骶段代偿弯Cobb角、矢状位整体失平衡距离、骨盆入射角、骨盆倾斜角、腰椎前凸角、胸腰段后凸角、胸段后凸角分别为:3.9±1.1cm、35.3°±13.1°、24.5°±7.3°、11.0±9.2cm、49.8°±20.7°、33.8°±12.8°、8.7°±16.6°、11.3°±19.5°、14.4°±6.8°;术后分别为:-0.1±1.0cm、11.5°±10.3°、3.3°±4.0°、3.7±6.4cm、49.8°±19.1°、22.6°±7.7°、32.3°±9.0°、2.2°±18.0°、23.5°±2.7°。患者术后冠状位及矢状位整体平衡良好,较术前明显改善(P0.05)。结论:术中俯卧位足跟连线中点、臀沟、C7棘突三标记点的共线可作为术中冠状位是否平衡简单而实用的参考;凹凸双侧充分松解,体位复位及配合内固定的整体复位可实现腰骶椎畸形的良好矫正,进而恢复冠状位即刻的整体平衡。     

单纯椎板减压治疗退变性椎管狭窄症并腰椎侧凸的疗效及其影响因素

目的：探讨单纯椎板减压治疗退变性椎管狭窄症并腰椎侧凸的效果及其影响因素。方法：1996年-2000年我科收治的资料完整的退变性椎管狭窄症合并腰椎侧凸患者57例，均采用单纯腰椎椎板减压术治疗。使用JOA评分标准进行疗效评价，根据JOA评分恢复率（recoverrate，RR）将患者分为效果满意组（RR≥50％）和效果不满意组（RR〈50％），对腰椎前凸角、侧凸角、腰椎活动度以及L4椎体倾斜率和侧向位移等影像学参数与l临床治疗效果的关系进行统计分析。结果：本组随访3～7年，平均5．1年，效果满意者42例，不满意者15例，统计分析显示腰椎前凸、活动度、L4椎体的倾斜率和手术减压节段对手术效果有显著影响（P〈0．05），与效果不满意组相比，疗效满意组患者术前腰椎前凸小，活动度低，L4椎体倾斜率不明显，需要手术减压的节段少。结论：对腰椎前凸较小、活动度低和L4椎体倾斜率较小的椎管狭窄症合并腰椎侧凸的患者使用短节段全椎板减压可以获得满意的疗效。     

腰椎体积CT值对诊断骨质疏松症的应用价值

目的 评估基于双层光谱CT腰椎扫描获得的椎体体积HU值在骨质疏松诊断中的应用价值。方法 回顾性收集2022年10月至2023年3月北京积水潭医院脊柱外科门诊患者91例。所有患者均接受过腰椎双层光谱CT扫描,包括QCT。同时测量纳入患者L1和L2椎体的体积HU值和基于QCT扫描的体积骨密度值。依据腰椎QCT骨密度诊断骨质疏松症的标准将研究对象分为骨量正常组、低骨量组和骨质疏松组,比较3组患者的一般情况,分析体积HU值与QCT测量的体积骨密度的关系。使用ROC曲线分别计算体积HU值诊断骨量减少和骨质疏松最佳诊断阈值以及使用逻辑回归模型确定性别、年龄和体积HU值与骨质疏松发生的关系。结果 L1和L2的平均体积HU值与QCT测量的BMD之间有极好的相关性（r= 0.941, P<0.001）;ROC诊断骨量减少和骨质疏松的最佳阈值分别为154.73 HU（灵敏度为92.9 %）和106.52 HU（灵敏度为86.6 %）;年龄和基于双层光谱CT测量的体积HU值与骨质疏松的发生显著相关（P<0.001）,OR值分别为1.172和0.928。结论 基于双层光谱CT测量的体积HU值和QCT测量的体积BMD之间有较好的相关性;基于腰椎体积HU值的阈值能准确预测骨量异常减低和骨质疏松,因此,体积HU值可以作为临床机会性筛查骨质疏松的补充手段。