胸腰椎经皮椎弓根螺钉置钉的准确性分析

目的:分析胸腰椎经皮椎弓根螺钉固定术的置钉准确性.方法:回顾分析2010年7月～2012年12月我院53例胸腰椎经皮椎弓根螺钉固定术患者,男31例,女22例;年龄18～73岁,平均51.2岁.腰椎退变性疾病24例,胸腰椎骨折29例.置钉节段为T8～S1.根据术后CT轴位扫描图像以及患者是否出现椎弓根螺钉相关并发症,将椎弓根螺钉位置分级:0级,螺钉位于椎弓根皮质内;1级,螺钉突破椎弓根骨壁但≤2mm;2级,螺钉突破椎弓根骨壁＞2mm,但无神经受压等症状;3级,出现螺钉相关并发症.结果:共置入椎弓根螺钉212枚,平均4.0枚/例.212枚螺钉中,0级175枚(82.5％);1级32枚(15.1％);2级4枚(1.9％);3级1枚(0.5％),患者出现神经受压症状,行翻修术.37枚位置不佳的螺钉中,24枚向内侧切出椎弓根,13枚向外侧切出.结论:胸腰椎经皮椎弓根螺钉固定技术虽置钉位置欠佳率较高,但很少发生2级以上置钉位置不佳者.     

导航辅助腰椎椎弓根螺钉置入的误差分析

目的：探讨导航辅助腰椎椎弓根螺钉置入的准确性和误差产生的原因。方法：16例腰椎疾病的患者，在导航辅助下置人76枚椎弓根螺钉，手术后行X线和CT检查，在矢状位测量螺钉与椎弓根上缘的相对位置、与椎体上缘的角度；横断位测量螺钉与椎弓根内壁的相对位置、与椎体中线的角度。并与手术导航图像的对应数值进行统计学比较。结果：有2枚螺钉偏头侧出椎弓根，术中纠正，1枚螺钉造成椎弓根外壁缺损而被取出，2枚螺钉偏外侧出椎弓根。其余螺钉手术后CT与手术中导航图像显示的位置角度比较没有显著性差异。导航可能产生两种偏差，一种是因为椎体之间的距离缩短，常见于腰椎骨折和腰椎不稳定的患者，手术过程中腰椎前凸加大，螺钉出椎弓根上缘或下缘；另一种是扩椎弓根时图像晃动，或者开路锥在椎弓根内调整位置时产生的虚假图像误导手术者判断错误。结论：在使用导航过程中要采取措施避免腰椎的前凸加大，根据静止的图像做出判断，以减小误差。     

An analysis of the anatomic features of the cervical spine using computed tomography to select safer screw insertion techniques

Purpose

The purpose of the present study was to evaluate the anatomic features of the cervical spine using computed tomography (CT) to select safer screw insertion techniques, particularly emphasizing the location of the transverse foramen.

Methods

Fifty patients who underwent multiplanar CT reconstruction were evaluated. There were 34 males and 16 females with an average age of 67 years. The parameters included the following measurements: foramen width (the size of the transverse foramen FW), foramen height (the size of the transverse foramen FH), pedicle width (PW), foramen angle (FA the position of the transverse foramen), pedicle transverse angle (PTA) and lateral mass angle (LMA).

Results

The mean FW ranged from 6.2 to 6.3 mm (n.s). The mean FH ranged from 5.0 to 5.7 mm, with significant differences between each vertebra, except for the FH between C4 and C5 and the FH between C5 and C6. The mean PW ranged from 5.4 to 6.1 mm. There were significant differences between each vertebra, except for the PW between C3 and C4 and the PW between C3 and C5. The mean FA ranged from 18.8° to 20.5°. There were significant differences between each vertebra, except for the FA between C3 and C6 and the FA between C4 and C5. The mean PTA ranged from 37.1° to 45.4°. There were significant differences between each vertebra, except for the PTA between C3 and C5. The mean LMA ranged from 1.0° to 5.3°. There were significant differences between each vertebra, except for the LMA between C4 and C5. The FW and FH exhibited no correlations with PW, PTA or LMA. FA was found to be positively correlated with both PTA and LMA. There was also a positive correlation between PTA and LMA.

Conclusions

We suggest that in cases in which pedicle screw insertion is difficult, lateral mass screws (LMS) can be inserted safely and longer sizes can be selected. In contrast, in cases in which LMS insertion is difficult, the insertion of pedicle screws can be performed relatively easy.     

Potential contribution of pedicle screw design to loosening rate in patients with degenerative diseases of the lumbar spine: An observational study

BACKGROUNDThe majority of published data report the results of biomechanical tests of various design pedicle screw performance. The clinical relevance and relative contribution of screw design to instrumentation stability have been insufficiently studied.AIMTo estimate the contribution of screw design to rate of pedicle screw loosening in patients with degenerative diseases of the lumbar spine.METHODSThis study is a prospective evaluation of 175 patients with degenerative diseases and instability of the lumbar spine segments. Participants underwent spinal instrumentation employing pedicle screws with posterior only or transforaminal interbody fusion. Follow-up was for 18 mo. Patients with signs of pedicle screw loosening on computed tomography were registered; logistic regression analysis was used to identify the factors that influenced the rate of loosening.RESULTSParameters included in the analysis were screw geometry, type of thread, external and internal screw diameter and helical pitch, bone density in Hounsfield units, number of levels fused, instrumentation without anterior support, laminectomy, and unilateral and bilateral total facet joint resection. The rate of screw loosening decreased with the increment in outer diameter, decrease in core diameter and helical pitch. The rate of screw loosening correlated positively with the number of fused levels and decreasing bone density. Bilateral facet joint removal significantly favored pedicle screw loosening. The influence of other factors was insignificant.CONCLUSIONScrew parameters had a significant impact on the loosening rate along with bone quality characteristics, the number of levels fused and the extensiveness of decompression. The significance of the influence of screw parameters was comparable to those of patient- and surgery-related factors. Pedicle screw loosening was influenced by helical pitch, inner and outer diameter, but screw geometry and thread type were insignificant factors.     

The feasibility of transpedicular screw fixation of the subaxial cervical spine in the Arab population: a computed tomography-based morphometric study

Background

Transpedicular screw fixation of the cervical spine provides excellent biomechanical stability. The feasibility of inserting a 3.5-mm screw in the pedicle requires a minimum pedicle diameter of 4.5 mm. This diameter allows at least 0.5 mm bony bridge medially and laterally in order to avoid pedicle violation which can result in neurovascular complications. We aim to evaluate the feasibility of this technique in Arab people since no data are available about this population.

Materials and methods

This cross-sectional study involved a retrospective review of computed tomography scans of normal cervical spines of 99 Arab adults. Ten morphometric measurements were obtained. Data were analyzed using a p value of ≤0.05 as the cut-off level of statistical significance.

Results

Our sample included 63 (63.6 %) males and 36 (36.4 %) females, with a mean age of 35.5 ± 16.5 years. The morphometric parameters of C3–C7 spine pedicles were larger in males than in females. The outer pedicle width (OPW) was <4.5 mm in >25 % of all subjects at C3–C6 vertebrae. Statistically significant differences in the OPW between males and females were noted at C3 (p = 0.032) and C6 (p = 0.004).

Conclusions

Inserting pedicle screws in the subaxial cervical spine is feasible among the majority of Arab people.

Level of evidence

Level 3.

     

三维CT重建模拟三种腰椎椎弓根螺钉置入方法的安全性分析

目的：通过计算机三维CT重建，测量三种腰椎椎弓根螺钉置入方法的置钉参数，探讨其安全适用节段。方法：在40例腰椎CT三维重建图像上应用人字嵴顶点法、Magerl法及Roy-Camille法模拟置钉．测量进钉点至椎弓根轴线的距离及置钉水平面角的安全范围．比较三种方法在腰椎各节段安全性的差异。结果：在L1～L4。“人字嵴顶点法”的进钉点到椎弓根轴线距离小于它其两种方法（P〈0．05）；在L5，Magerl法的距离最短（P〈0．05）。在L1、L2．三种方法置钉水平面角（TSA）的安全范围无显著性差异（P〉0．05）；在L3、L4，“人字嵴顶点法”与Magerl法的置钉TSA的安全范围大于Roy-Camille法（P〈0．01）．但两者之间无显著性差异（P〉0．05）；在L5．Magerl法的安全范围最大（P〈0．05）。结论：在L1～L4，“人字嵴顶点法”是理想置钉方法：在L5，Magerl法是理想置钉方法：Roy-Camille法仅适合于L1、L2．不推荐在L3～L5应用。     

Translaminar screw fixation in the lumbar spine: technique, indications, results

Translaminar screw fixation of the lumbar spine represents a simple and effective technique for short segment fusion in the degenerative spine. Clinical experience with 173 patients who underwent translaminar screw fixation revealed a fusion rate of 94%. The indications for translaminar screw fixation as a primary fixation procedure are: segmental dysfunction, lumbar spinal stenosis with painful degenerative changes, segmental revision surgery after discectomies, and painful disc-related syndromes such as internal disc disruption and lumbar disc herniation with concomitant degenerative changes. As an additional stabilization procedure, translaminar screws can be used to augment anterior fusion or reinforce pedicle systems. Translaminar screw fixation achieves as high fusion rate provided the biomechanical principles of the lumbar spine with an intact anterior column are respected and a meticulous operative technique is employed to enhance bony ingrowth of the graft. Received: 12 January 1998 Revised: 18 March 1998 Accepted: 6 April 1998     

Complications of transpedicular screw fixation in the cervical spine

Today, posterior stabilization of the cervical spine is most frequently performed by lateral mass screws or spinous process wiring. These techniques do not always provide sufficient stability, and anterior fusion procedures are added secondarily. Recently, transpedicular screw fixation of the cervical spine has been introduced to provide a one-stage stable posterior fixation. The aim of the present prospective study is to examine if cervical pedicle screw fixation can be done by low risk and to identify potential risk factors associated with this technique. All patients stabilized by cervical transpedicular screw fixation between 1999 and 2002 were included. Cervical disorders included multisegmental degenerative instability with cervical myelopathy in 16 patients, segmental instability caused by rheumatoid arthritis in three, trauma in five and instability caused by infection in two patients. In most cases additional decompression of the spinal cord and bone graft placement were performed. Pre-operative and post-operative CT-scans (2-mm cuts) and plain X-rays served to determine changes in alignment and the position of the screws. Clinical outcome was assessed in all cases. Ninety-four cervical pedicle screws were implanted in 26 patients, most frequently at the C3 (26 screws) and C4 levels (19 screws). Radiologically 66 screws (70%) were placed correctly (maximal breach 1 mm) whereas 20 screws (21%) were misplaced with reduction of mechanical strength, slight narrowing of the vertebral artery canal (<25%) or the lateral recess without compression of neural structures. However, these misplacements were asymptomatic in all cases. Another eight screws (9%) had a critical breach. Four of them showed a narrowing of the vertebral artery canal of more then 25%, in all cases without vascular problems. Three screws passed through the intervertebral foramen, causing temporary paresis in one case and a new sensory loss in another. In the latter patient revision surgery was performed. The screw was loosened and had to be corrected. The only statistically significant risk factor was the level of surgery: all critical breaches were seen from C3 to C5. Percutaneous application of the screws reduced the risk for misplacement, although this finding was not statistically significant. There was also a remarkable learning curve. Instrumentation with cervical transpedicular screws results in very stable fixation. However, with the use of new techniques like percutaneous screw application or computerized image guidance there remains a risk for damaging nerve roots or the vertebral artery. This technique should be reserved for highly selected patients with clear indications and to highly experienced spine surgeons.     

A new lumbar fixation device alternative to pedicle-based stabilization for lumbar spine: In vitro cadaver investigation

Context: To evaluate the stability provided by a new bilateral fixation technique using an in vitro investigation for posterior lumbar segmental instrumentation.

Design: Experimental cadaver study. In this study, we propose an alternative technique for a posterior lumbar fixation technique called “inferior-oblique transdiscal fixation” (IOTF).

Setting: Study performed at Engineering Center for Orthopedic Research Exellence (ECORE) in Toledo University-Ohio.

Participants: Six human lumbar cadaveric specimen used in this study.

Interventions: In this study, we propose an alternative technique for a posterior lumbar fixation technique called “inferior-oblique transdiscal fixation” (IOTF). As a novel contribution to the classical technique, the entry point of the screw is the supero-lateral point of the intersecting line drawn between the corpus and the pedicle of the upper vertebra. This approach enables the fixation of two adjacent vertebrae using a single screw on each side without utilizing connecting rods.

Outcome Measures: Flexion (Flex), extension (Ext), right and left lateral bending (LB & RB), and right and left axial rotation (LR & RR), and the position data were captured at each load step using the Optotrak motion measurement system and compared for IOTF and posterior transpedicular stabilization.

Results: The Posterior stabilization system (PSS) and IOTF significantly reduced the ROM of L4-L5 segment compared to intact segment’s ROM. During axial rotation (AR) IOTF fused index segment more than PSS. Besides this, addition of transforaminal lumbar interbody fusion (TLIF) cage improved the stabilization of IOTF system during flexion, extension and lateral bending. Whereas, PSS yielded better fusion results during extension compared to IOTF with and without interbody fusion cages.

Conclusions: We hypothesized that the new posterior bilateral system would significantly decrease motion compared to the intact spine. This cadaver study showed that the proposed new posterior fusion technique IOTF fused the index segment in a similar fashion to the classical pedicle screw fusion technique.     

Abdu手术（经椎弓根椎体间内固定）治疗腰椎滑脱症

目的 应用Abdu手术（经椎弓根椎体间内固定）治疗腰椎滑脱症。方法 采用一种治疗腰椎滑脱症的新方法“经椎弓根椎体间内固定系统”（PTSF），其特点在于两枚骶骨螺钉从骶1椎弓根进入，向上、内、前方穿过骶岬、L5、S1椎间盘，进入L5椎体内，不穿透其前缘，结合两枚L4椎弓根螺钉，以具有防止螺钉轴向滑移功能的棘齿槽式钢板、垫片连接 ，构成PTSF内固定系统对腰骶椎的坚持固定。结果 临床应用6例，获随访5例，平均随访5－8月，按Henderson标准评价；优四例，良一例，无严重并发症。结论 经椎弓椎体间内固定系统（PTSF）具有内固定坚强、安全、有效的特点，近期随访临床疗效满意。     

Electromyography stimulation compared with intraoperative O-arm imaging for evaluating pedicle screw breaches in lumbar spine surgery: a prospective analysis of 1006 screws in 164 patients

Background context

Lumbar pedicle screw placement can be technically challenging. Malpositioned screws occur in up to 15% of patients and could result in radiculopathy or instrumentation failure.

胸腰椎椎弓根螺钉植入技术的研究进展

胸腰椎椎弓根螺钉内固定技术的开展，有力地推动了脊柱外科的发展。该技术的关键是，螺钉的植入必须位于三维空间中唯一的一个正确通道上，即按照正确的矢状面角及水平面角，沿椎弓根的长轴穿过椎弓根这一狭小的骨性管道达惟体内。近年来，胸腰椎椎弓根螺钉植入技术的研究取得了很大发展，尤其是术中监测手段，已从传统的X线透视或摄片监测定位发展到计算机辅助技术进行可视化监测。本文结合国内外研究成果，对胸腰椎椎弓根螺钉植入技术的研究进展进行概述。     

Translaminar screw fixation in lumbar spine pathology

Summary Two technical variations of the method of translaminar screw fixation for unstable lumbar and lumbosacral segments are presented. Distraction-arthrodesis with intraarticular bone grafts allows definitive enlargement of narrowed foramina with consecutive root decompression as well as repositioning and intracanalicular decompression in cases of instability after lumbar disc surgery and in degenerative spondylolisthesis. Reconstruction of a hemilamina after hemilaminectomy and facet reduction allows reconstitution of the spinal canal and its posterior parts as well as direct treatment of intraforaminal pathology.     

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.     

How to interpret computed tomography of the lumbar spine

Computed tomography (CT) of the spine has remained an important tool in the investigation of spinal pathology. This article helps to explain the basics of CT of the lumbar spine to allow the clinician better use of this diagnostic tool.     

New parameters to represent the position of the aorta relative to the spine for pedicle screw placement

Parameters of the position of the aorta in previous reports were determined for anterior surgery. This study evaluated the relative position of the aorta to the spine by new parameters, which could enhance the safety of pedicle screw placement. Three parameters were defined in a new Cartesian coordinate system. We selected an entry point of a left pedicle screw as the origin. The transverse plane was determined to include both the bases of the superior facet and to be parallel to the upper endplate of the vertebral body. A line connecting the entry points of both sides was defined as the X-axis. The angle formed by the Y-axis and a line connecting the origin and the center of the aorta was defined as the left pedicle–aorta angle. The length of a line connecting the origin and the aorta edge was defined as the left pedicle–aorta distance. Distance from the edge of the aorta to the X-axis was defined as the pedicular line–aorta distance. These parameters were measured preoperatively in 293 vertebral bodies of 24 patients with a right thoracic curve. We simulated the placement of the pedicle screw with variable length and with some direction error. We defined a warning pedicle as that when the aorta enters the expected area of the screw. Sensitivity analysis was performed to find the warning pedicle ratio in 12 scenarios. The left pedicle–aorta angle averaged 29.7° at the thoracic spine and −16.3° at the lumbar spine; the left pedicle–aorta distance averaged 23.7 and 55.2 mm; the pedicular line–aorta distance averaged 18.3 and 51.0 mm, respectively. The ratio of warning pedicles was consistently high at T4–5 and T10–12. When a left pedicle screw perforates an anterior/lateral wall of the vertebral body, the aorta may be at risk. These new parameters enable surgeons to intuitively understand the position of the aorta in surgical planning or in placement of a pedicle screw.     

应用TSRH椎弓根钉系统治疗腰椎不稳症

目的：评价ＴＳＲＨ椎弓根钉系统在治疗腰椎不稳症中效果。方法：对２１例腰椎不稳症患者行ＴＳＲＨ椎根钉系统内固定手术,术后随诊分析。结果：２１例获平均２０．９个月的随访,植骨晤率为９５．２％,疗效满意。结论：ＴＳＲＨ椎弓根钉系统简单、固定牢靠,适用于腰椎不稳症的手术治疗。     

透视及导航下颈椎椎弓根螺钉内固定术的临床应用经验

目的　报告使用透视下及无线主动式红外诱导计算机导航引导下进行颈椎椎弓根钉固定手术的经验 ,分析手术成功的要素。方法　自 2 0 0 1年 10月至 2 0 0 2年 12月共行颈椎椎弓根螺钉 -AXIS钛板内固定 2 9例 ,男性 18例 ,女性 11例。年龄 2 6岁～ 76岁 ,平均年龄 4 9.4岁。使用C形臂X线透视下螺钉置入 2 5例 ,无线主动式红外诱导计算机导航下椎弓根内固定 4例。共置入椎弓根螺钉 174枚。结果　 174枚螺钉中有 15 5枚 (89% )位置正确。 19枚螺钉存在不同程度的偏差 ,均为内倾不够 ,1例出现一过性神经根合并症。计算机导航置入螺钉 2 4枚 ,位置正确率 10 0 %。术前颈椎后凸者固定节段曲度平均- 12 .1°术后平均 - 0 .6° ,明显得到纠正。术后 3个月和 6个月的随诊 ,颈椎曲度和固定节段椎体高度均维持 ,没有出现内固定物松动 ,螺钉断裂等情况。结论　颈椎椎弓根钉固定手术是颈椎获得牢固固定的方法 ,为颈椎后路手术提供了更广的操作空间 ,免去部分同时前路手术的需要 ,而且可以用于颈椎后凸的矫正。但是结构的复杂性和变异性及周围的神经血管使手术难度加大 ,在透视下可以比较安全地置入螺钉 ,更好的方法是使用计算机导航技术。这一技术具有良好的临床应用前景。     

Pedicle screw insertion accuracy with different assisted methods: a systematic review and meta-analysis of comparative studies

Studies revealed that navigation systems that provided intraoperative assistance might improve pedicle screw insertion accuracy, and also implied that different systems provided different pedicle screw insertion accuracy. A systematic review and meta-analysis was conducted to focus on the pedicle screw insertion accuracy with or without the assistance of image-guided system, and the variance among the different navigation systems. Comparative studies were searched on pedicle screw insertion accuracy between conventional and navigated method, and among different navigation systems. A total of 43 papers, including 28 clinical, 14 cadaveric and 1 model studies, were included in the current study. For clinical articles, there were 3 randomized clinical trials, 4 prospective comparative studies and 21 retrospective comparative studies. The incidence of pedicle violation among computer tomography-based navigation method group was statistically significantly less than that observed among the conventional group (OR 95% CI, in vivo: 0.32–0.60; in vitro: 0.24–0.75 P < 0.01). Two-dimensional fluoroscopy-based navigation system (OR 95% CI, in vivo: 0.27–0.48; in vitro: 0.43–0.88 P < 0.01) and three-dimension fluoroscopy-based navigation system (OR 95% CI, in vivo: 0.09–0.38; in vitro: 0.09–0.36 P < 0.01) also obtained significant reduced screw deviation rate over traditional methods. Between navigated approaches, statistically insignificant individual and pooled RR values were observed for all in vivo subgroups. Pooled estimate of in vitro studies show that computer tomography-based and three-dimension fluoroscopy-based navigation system provided more accurate pedicle screw insertion over two-dimension fluoroscopy-based navigation system. Our review showed that navigation provided a higher accuracy in the placement of pedicle screws compared with conventional methods. The superiority of navigation systems was obvious when they were applied to abnormal spinal structure. Although no strong in vivo evidence has detected significantly different pedicle screw placement accuracy among the three major navigation systems, meta-analysis revealed the variance in pedicle screw insertion accuracy with different navigation methods.