In vivo study of extracellular matrix coating enhancing fixation of the pedicle screw-bone’s interface

Background  Based on in vivo research on the effect of the coating of the extracellular matrix composition of pedicle screws on the conduction and induction of bone formation in young sheep, the aim of this study was to investigate the application of coated pedicle screws in sheep with scoliosis whose spines are under constant development.
Methods  Four groups of pedicle screws were randomly implanted into bilateral L2–L5 pedicles of 2.5- to 3-month-old sheep. A static experiment was performed on one side and a loading test was performed on the other side by implanting connecting rods at the L2–L3 and L4–L5 segments. The changes in the force on the coated screws and the combination of the surface of the coated screws with the surrounding bone in the growth process of young sheep’s spines with aging were observed. After 3 months, the lumbar vertebrae with the screws were removed and examined by micro-CT, histological, and biomechanical analyses.
Results  Under nonloading conditions, there is bone formation around the surfaces of coated screws. The bone forming on the surface of collagen/chondroitin sulfate/hydroxyapatite coating of pedicle screws is the most, the one of the collagen / chondroitin sulfate coating and hydroxyapatite coating is followed, and no significant difference between the two groups. In terms of the trabecular bone morphology parameters of the region of interest around the surface of the pedicle screws, such as bone mineral content, bone mineral density, tissue mineral content, tissue bone mineral density, bone volume fraction, and connection density, those associated with collagen/chondroitin sulfate/hydroxyapatite coatings are largest and those unassociated with coatings are smallest. Under nonloading conditions, the pullout strength of the collagen/chondroitin sulfate/hydroxyapatite-coated screws was largest, and that of the uncoated screws was minimal (P <0.01). Under loading conditions, the maximum pullout strength of each group of pedicle screws was less than that of the pedicle screws in the nonloading state (P <0.01) with no significant difference between the groups (P >0.05).  
Conclusions  Under nonloading conditions, the coatings of both organic and inorganic components of the extracellular matrix of titanium pedicle screws can conduct or induce bone formation around the surface of the screws. The ability of collagen/chondroitin sulfate/hydroxyapatite coatings to induce bone formation is stronger; under loading conditions, a large amount of connective tissue formed around the surfaces of the screws in each group. No significant differences were found between the groups.

     

Lumbus dosal spine

<正>209195 Biomechanical analysis of a novel perfusional pedicle screw augmentation with bone cement in osteoporotic vertebra/Yang Huilin(Dept Orthopaed First Affil Hosp Soochow Univ Suzhou 215006)…∥Chin J Orthop.-2009,29(3).-241~247Objective To clarify the biomechanical stability of novel perfusional pedicle screw(NPPS) in spinal vertebrae with osteoporosis.Methods Forty-two vertebrae(T11 to L5) obtained from 6 formalin preserved cadavers (5 males and 1 females; mean age,73 years) were used.The mean bone mineral density was (0.696±0.14)g/cm2.The NPPS was inserted into one pedicle of each vertebra,then early-doughtime cement 2 ml was perfused with the bone cement pusher and perfusion tube under X-ray into the vertebra body through the hollow part of NPPS,and the control screw,an improved CD2 screw,was inserted into the contralateral pedicle.Three vertebrae were chosen to observe the distribution of cement,and the other 39 vertebrae were randomly divided into three groups to make the pull-out test,rotation-out torque test,and cyclic bending resistance test respectively.Ten novel perfusional pedicle screws and ten control screws were respectively examined by three-point bend test.Results Cement perfused around the side holes of the distal screw in all vertebral body and no cement leakage occured.The mean maximum force at pull-out was (760±178) N for the NPPS and (355±87)N for the control screw.The mean maximum rotating-out torque was (1.34±0.377)N·m for the NPPS and (0.488±0.205) N·m for the control screw.In cyclic bending resistance test,the NPPS was found to with stand a greater number of cycles or greater loading before loosening.About 30.8%(4/13) of the NPPS became loosing (displacement>2.000 mm),the mean load of the loosening screws was (150±46)N and the mean displacement of the non-loosening screws was (0.661±0.289) mm.All of the control screws were loosening among 50-200 N before 800 cycles.Conclusion The manipulation of NPPS is simple with the application of cement pusher and pe     

Biomechanical comparison of cervical transfacet pedicle screws versus pedicle screws

Background Transfacet pedicle screws provide another alternative for standard pedicle screw placement for plate fixation in the lumbar spine. However, few studies looking at transfacet pedicle screw fixation in the cervical spine are available. Therefore, cervical transfacet pedicle screw fixation and standard pedicle screw fixation techniques were biomechanically compared in this study. Methods Ten fresh human cadaveric cervical spines were harvested. On one side, transfacet pedicle screws were placed at the C3-4, C5-6, and C7-T1 levels. On the other side, pedicle screws were placed at the C3, C5, and C7 levels. The screw insertion technique at each level was randomized for right or left. The starting point for the transfacet pedicle screw insertion was located at the midpoint of the inferolateral quadrant of the lateral mass and the direction of the screw was about 50° caudally in the sagittal plane and about 45° toward the midline in the axial plane. Screws were placed from the inferior articular process, across the facet complex and the pedicle into the body of the caudal vertebra. The entry point for the pedicle screw was located at the midpoint of the superolateral quadrant of the lateral mass, and the direction of the screw was about 45° toward the midline in the axial plane and toward the upper third of the vertebral body in the sagittal plane. After screw placement we performed axial pullout testing. Results All the cervical transfacet pedicle screws and the pedicle screws were inserted successfully. The mean pullout strength for the transfacet pedicle screws was 694 N, while for the pedicle screws 670 N （P=0.013）. In all but six instances （10%）, the pedicle screw pullout values exceeded the values for the transfacet pedicle screws; this occurred three times at the C3/C4 level, twice at the C5/C6 level and once at the C7/T1 level. The greatest pullout strength difference at a single level was observed at the C5/C6 level, with a mean difference of 38 N （t=-1.557, P=0.154）. The C7/T1 level h     

Lumbar spine superior-level facet joint violations: percutaneous versus open pedicle screw insertion using intraoperative 3-dimensional computer-assisted navigation

Background Percutaneous pedicle screw use has a high rate of cranial facet joint violations （FVs） because of the facet joint being indirectly visualized.Computer-assisted navigation shows the anatomic structures clearly,and may help to lower the rate of FVs during pedicle screw insertion.This study used computed tomography （CT） to evaluate and compare the incidence of FVs between percutaneous and open surgeries employing computer-assisted navigation for the implantation of pedicle screw instrumentation during lumbar fusions.Methods A prospective study,including 142 patients having lumbar and lumbosacral fusion,was conducted between January 2013 and April 2014.All patients had bilateral posterior pedicle screw-rod instrumentation （top-loading screws） implanted by the same group of surgeons; intraoperative 3-dimensional computer navigation was used during the procedures.All patients underwent CT examinations within 6 months postoperation.The CT scans were independently reviewed by three reviewers blinded to the technique used.Results The cohort comprised 68 percutaneous and 74 open cases （136 and 148 superior-level pedicle screw placements,respectively）.Overall,superior-level FVs occurred in 20 patients （20/142,14.1％）,involving 27 top screws （27/284,9.5％）.The percutaneous technique （7.4％ of patients,3.7％ of top screws） had a significantly lower violation rate than the open procedure （20.3％ of patients,14.9％ of top screws）.The open group also had significantly more serious violations than did the percutaneous group.Both groups had a higher violation rate when the cranial fixation involved the L5.A 1-level open procedure had a higher violation rate than did the 2-and 3-level surgeries.Conclusions With computer-assisted navigation,the placement of top-loading percutaneous screws carries a lower risk of adjacent-FVs than does the open technique; when FVs occur,they tend to be less serious.Performing a single-level open lumbar fusion,or the fusion of the L5-S1 segment,requires     

Comparison of the clinical accuracy of cervical (C2–C7) pedicle screw insertion assisted by fluoroscopy, computed tomography- based navigation, and intraoperative three-dimensional C-arm navigation

Background The complicated anatomy of the cervical spine and the variation among pedicles reduces the accuracy and increases the risk of neurovascular complications associated with screw implantation in this region. In this study, we compared the accuracy of cervical （C2-C7） pedicle screw fixation assisted by X-ray fluoroscopy, computed tomography （CT）-based navigation, or intraoperative three-dimensional （3D） C-arm navigation.Methods This prospective cohort study was performed in 82 consecutive patients who underwent cervical pedicle screw fixation. The accuracy of screw insertion was assessed by postoperative CT scan with 3D reconstruction. The accuracy of screw insertion was assessed as： excellent （screw completely within pedicle）; acceptable （≤ 1 mm screw outside pedicle cortex）; poor （〉1 mm screw outside pedicle cortex）.Results A total of 145 screws were inserted in 24 patients who underwent C-arm fluoroscopy. Of these, 96 screws （66.2%） were excellent, 37 （25.5%） were acceptable, and 12 （8.3%） were poor. One hundred and fifty-nine screws were inserted in 29 patients in the CT-based navigation group. Among these, 141 （88.7%） were excellent, 14 （8.8%） were acceptable, and 4 （2.5%） were poor. A total of 140 screws were inserted in 29 patients in the intraoperative 3D C-arm navigation group, of which 127 （90.7%） were excellent, and 13 （9.3%） were acceptable. No severe or permanent neurovascular complications associated with screw insertion were observed in any patient.Conclusione CT-based and intraoperative 3D C-arm navigation were similarly accurate, and were both significantly more accurate than C-arm fluoroscopy for guiding cervical pedicle screw fixation. They were able to accurately guide the angle and depth of screw placement using visual 3D images. These two techniques are therefore preferable for high-risk cervical pedicle screw fixation. The ease and convenience of intraoperative 3D C-arm navigation suggests that it may replace virtual-fluoroscopy and CT-based navigation systems in future clinical applications.     

Position and complications of pedicle screw insertion with or without image-navigation techniques in the thoracolumbar spine：a meta-analysis of comparative studies

Computer-navigated pedicle screw insertion is applied to the thoracic and lumbar spine to attain high insertion accuracy and a low rate of screw-related complications.However,some in vivo and in vitro studies have shown that no advantages are gained with the use of navigation techniques compared to conventional techniques.Additionally,inconsistent conclusions have been drawn in various studies due to different population characteristics and methods used to assess the accuracy of screw placement.Moreover,it is not clear whether pedicle screw insertion with navigation techniques decreases the incidence of screw-related complications.Therefore,this study was sought to perform a meta-analysis of all available prospective evidence regarding pedicle screw insertion with or without navigation techniques in human thoracic and lumbar spine.We considered in vivo comparative studies that assessed the results of pedicle screw placement with or without navigation techniques.PubMed,Ovid MEDLINE and EMBASE databases were searched.Three published randomized controlled trials（RCTs） and nine retrospective comparative studies met the inclusion criteria.These studies included a total of 732 patients in whom 4,953 screws were inserted.In conclusion,accuracy of the position of grade I,II,III and IV screws and complication rate related to pedicle screw placement were significantly increased when navigation techniques were used in comparison to conventional techniques.Future research in this area should include RCTs with well-planned methodology to limit bias and report on validated,patient-based outcome measures.     

Study of Bone-screw Surface Fixation in Lumbar Dynamic Stabilization

Background:We aimed to use the animal model of dynamic fixation to examine the interaction of the pedicle screw surface with surrounding bone,and determine whether pedicle screws achieve good mechanica...     

Positioning study of cervical vertebra pedicle axial line projective point by computed tomography image reconstruction

Background  Safe placement of the screws is a critical aspect of trans-pedicle internal fixation, and little information on in vivo morphology of the cervical vertebrae pedicle measured with imaging methods is available. The aim of this study was to measure the dimensions of cervical vertebrae C3 to C7 and provide screw length, screw diameter and tilt angle for clinical cervical vertebra trans-pedicle internal fixation.

Methods  Thirty Chinese men and women underwent high-speed spiral computed tomography measurements to obtain data for C3 to C7, and the morphology of the cervical vertebra pedicles was reconstructed.

Results  Reconstructed computer tomography image data revealed that: (1) pedicle sponge width increased incrementally from C3 to C7, (2) pedicle depth was similar for C3 to C7, (3) pedicle angle decreased incrementally from 47.20° to 33.76° for C3 to C7, and (4) pedicle point to midline distance was similar for C3 to C7. There were no statistical differences in morphological data between the right and the left side. Men had statistically larger values than women for all morphological parameters.

Conclusions  Reconstructed computed tomography images can provide useful data for clinical cervical vertebra trans-pedicle internal fixation. The individual measurement of cervical vertebra pedicles is recommended for safe placement of trans-vertebra pedicle screws.

     

Surgical treatment of degenerative scoliosis

Objective To investigate the techniques of posterior lumbar interbody fusion and pedicle screws in the treatment of degenerative scoliosis and evaluate their clinical significance. Methods Twenty five patients with degenerative scoliosis were treated operatively during 1997 -2002. Among the 25 pateints,13 pateints were treated with Brantigan I/F carbon cages in 28 intervertebral spaces,7 patients were treated with Prospace cages in 15 spaces, 1 patient was treated with CONTACT cages in 2 spaces. The correcting effects, complications and follow-up results were analyzed retrospectively. Results The average correction rate of scoliosis was 59 % and the rate of pain relief was 88 %. There were a case of pseudoarthritis and a case of embolism. During follow-up, correction rate and height of dics spaces were not lost nor shift of interbody cages. Conclusion Posterior pedicle screws combined with interbody fusion is a safe and effective treatment for degenerative scoliosis. 5 refs, 2 figs.     

Posterior Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis Patients： a Comparison of All Pedicle Screws versus Hybrid Instrumentation

Objective To analyze the influence of segmental pedicle screws versus hybrid instrumentation on the correction results in adolescent idiopathic scoliosis patients undergoing posterior selective thoracic fusion. Methods By reviewing the medical records and roentgenograms of adolescent idiopathic scoliosis patients who underwent selective thoracic fusion from February 2000 to January 2007 in our hospital, the patients were divided into 2 groups according to different instrumentation fashions： Group A was hook-screw-rod （hybrid） internal fixation type, Group B was screw-rod （all pedicle screws） internal fixation type, and the screws were used in every segment on the concave side of the thoracic curve. The parameters of the scoliosis were measured and the correction results were analyzed. Results Totally, 48 patients （7 males, 41 females） were included, with an average age of 14.4 years old and a mean follow-up time of 12.3 months. Thirty and 18 patients were assigned to group A and group B, respectively. The mean preoperative coronal Cobb angles of the thoracic curve were 48.8° and 47.4°, respectively. After surgery, they were corrected to 13.7° and 6.8°, respectively. At final follow-up, they were 17.0° and 9.5°, with an average correction rate of 64.6% and 79.0%, respectively, and the correction rate of group B was significantly higher than that of group A （P=0.003）. The mean preoperative coronal Cobb angles of the lumbar curve were 32.6° and 35.2°, respectively. After surgery, they were corrected to 8.6° and 8.3°, respectively. At final follow-up, they were 10.3° and 11.1°, with an average correction rate of 66.8% and 69.9%, respectively, and the correction rate of group B was significantly higher than that of group A （P=0.003）. The correction loss of the thoracic curve and lumbar curve in the 2 groups were 3.1° and 1.8°, 2.4° and 2.4°, respectively. No significant difference was noted （both P〉0.05）. The decompensation rate at final follow-up in these 2 groups were 4% （1/25） and 7.1% （1/14） respectively, with no significant difference （P〉0.05）.     

个体化导航模板辅助儿童胸椎椎弓根螺钉置钉准确性实验研究

目的:利用计算机辅助设计与快速成形技术为儿童胸椎椎弓根螺钉置入提供一种个性化、精确定位的方法。方法:对4具胸椎尸体标本进行CT扫描,根据CT扫描资料,利用逆向工程原理及快速成型技术设计制造出个体化导航模板,利用个体化导航模板在尸体标本上辅助置入胸椎椎弓根螺钉,所有螺钉的置入由同一位具有腰椎椎弓根螺钉置钉经验但无胸椎椎弓根螺钉置钉经验的骨科医师进行操作,随后根据CT扫描评价椎弓根螺钉位置。结果:共设计制作48个导航模板,辅助置入96枚胸椎椎弓根螺钉,CT扫描发现所有螺钉均准确置入相应椎弓根内。结论:数字化导航模板辅助胸椎椎弓根螺钉置钉准确性高,操作简单,为儿童胸椎椎弓根螺钉的准确置入提供了一种新的、可行方法。     

快速成型胸椎个体化导航模板精确度实验研究

目的：观察快速成型胸椎个体化导航模板的精确度,为快速成型个体化导航模板的临床使用提供参考。方法：选取12个完整的胸椎干燥骨标本,根据其CT扫描资料,利用计算机辅助设计及快速成型技术设计制作出相应的胸椎模型及个体化导航模板,通过个体化导航模板在胸椎标本及其模型上应用直径2．0mm的钻头模拟椎弓根螺钉置钉手术,直视观察钻头在椎弓根及椎体内的位置及走行方向。用精确度为0．02mm的游标卡尺对快速成型胸椎模型的精确性进行测量。结果：个体化导航模板和相应的胸椎标本及其模型后部解剖结构之间轮廓一致,贴附吻合良好,置入椎弓根进钉通道的钻头均完全位于椎弓根及椎体内,其走行方向和椎弓根的走行方向一致;所有胸椎模型和相应胸椎标本的解剖形态完全一致,胸椎标本和模型之间的误差范围在（0．49±0．28）mm之间。结论：虽然快速成型模型与实物之间有一定的误差,但其误差不影响对椎弓根准确定位及定向的精度要求。     

漏斗技术在上胸椎置人椎弓根螺钉中的应用

目的 评价应用漏斗技术置入上胸椎(T1～T5)椎弓根螺钉的安全性并探讨其置钉方法.方法 回顾性分析2006年3月至2010年10月间行椎弓根螺钉固定涉及上胸椎(T1～T5)且获得随访的病例共105例,男57例,女48例,年龄14～ 65岁,平均40.3岁,其中采用漏斗技术置钉的共54例患者(设为A组),采用徒手法置钉的共51例患者(设为B组).记录术中和术后出现的血管、神经、内脏损伤等并发症;术后行CT扫描,评价螺钉的位置,记录所有穿透骨皮质螺钉的数目和距离;比较分析A、B两组间及不同节段间椎弓根螺钉的不良置钉率.结果 105例患者在上胸椎(T1 ～T5)共置入椎弓根螺钉402枚,术中13枚椎弓根发生骨折,4例患者术中出现硬膜撕裂,所有患者末出现大血管、脊髓及肺部损伤相关并发症.术后CT扫描证实45枚螺钉穿破椎弓根皮质(不良置钉率11.2％),其中A组不良置钉率为10.14％,组内不同节段间不良置钉率差异无统计学意义(x2 =0.48,P=0.98);B组不良置钉率为12.31％,组内不同节段间不良置钉率也差异无统计学意义(,=2.55,P=0.64).两组间比较不良置钉率差异无统计学意义(x2 =0.47,P=0.49).25枚穿破椎体外侧壁,17枚穿破椎体内侧壁,3枚穿破椎体前壁.59例术前合并神经功能损害的患者,术后37例神经功能得到1～3级改善.结论 在上胸椎采用漏斗技术行胸椎椎弓根螺钉置入是安全、可靠的.     

重度特发性脊柱侧凸胸椎椎弓根螺钉徒手置入精确性的CT评价

目的：应用CT分析重度特发性脊柱侧凸胸椎椎弓根徒手螺钉置入的精确性。方法：选择1996年6月至2006年12月有完整术后CT资料的重度特发性脊柱侧凸患者20例。术前主胸弯冠状面Cobb角82°～142°（96.3°±14.3°）,主弯后凸角66.2°±12.4°。术中采用徒手直视下胸椎椎弓根螺钉置入,术后根据轴位CT扫描评价螺钉置入椎弓根的精确性。结果：共置入174枚胸椎椎弓根螺钉,术后CT密扫157枚螺钉（90.2%）完全在椎弓根皮质骨内,9例17枚螺钉（9.8％）发生错置：11枚螺钉（6.3％）偏外侧,其中9枚穿破皮质≤2 mm,2枚穿破皮质在2～4 mm;6枚螺钉（3.5％）偏内侧,其中3枚穿破皮质≤ 2 mm,3枚穿破皮质在2～4 mm。凸侧共置入椎弓根螺钉94枚,其中错置6枚,准确率为93.6%,凹侧共置入80枚,其中错置11枚,准确率为86.3%,凹侧与凸侧螺钉置入准确率比较无统计学差异（P>0.05）。所有病例未发生神经并发症。结论：应用徒手法行重度特发性脊柱侧凸胸椎椎弓根螺钉置入精确度较高,但有一定的误置率。     

CT三维重建配合3D打印技术在辅助寰枢椎椎弓根螺钉置入的应用价值评估

目的:探讨CT三维重建配合3D打印技术在辅助寰枢椎椎弓根螺钉置入的应用价值。方法:通过CT三维重建的多种后处理技术明确寰枢椎病变13例作为观察组,再将CT三维重建、逆向工程原理及快速成形技术相结合,设计出一种新型的导航模板,辅助椎弓根螺钉置入,并与13例之前已通过X线透视置钉法的病例（对照组）进行置钉效果比较。结果:对照组13例共置椎弓根螺钉41枚,其中Ⅰ类置钉9枚,Ⅱ类置钉18枚,Ⅲ类置钉14枚,成功率65.9%;观察组共打印颈椎模型13例,设计导向模板21个,5例由于先前通过X线透视仅在枢椎两侧的椎弓根内置钉,只制作出枢椎的导航模板;模拟手术同样置钉41枚,其中Ⅰ类置钉15枚,Ⅱ类置钉21枚,Ⅲ类置钉5枚,成功率87.8%。结论:CT三维重建的各种后处理技术不仅能够准确的判断寰枢椎病变,并能配合3D打印技术,制作出个体化的导航模板,使上颈椎椎弓根螺钉的置入变得既安全又省时,并能在术后准确评估置钉效果。     

CT机监控定位在胸椎椎弓根钉内固定术中的应用

目的：探讨CT机监控定位在胸椎内固定术中的应用及注意事项。方法：18例患，男13例，女5例，均采用CT机监控下椎弓根置管定位，置入胸椎椎弓根钉共74颗。结果：术后CT扫描证实置钉优良率达100％。结果：CT机监控椎弓根置管定位方法，有效解决了胸椎椎弓根钉内固定术这一难题。     

经中上胸椎肋椎关节内固定的解剖学研究

目的通过测量T1—8节段胸椎肋椎关节的形态学特征,探讨经肋椎关节进钉的可行性及临床意义。方法选择12具国人胸椎标本（男7、女5）共96个椎体,选取T4—5节段,使用康辉6．0mm椎弓根螺钉进行经椎肋关节内固定,并使用X线评估螺钉置人位置,并实体测量T1—8每个椎体肋椎关节及相应节段椎弓根的横径、钉道长度及e角（肋椎关节、椎弓根轴线与矢状线的夹角）。结果各节段肋椎关节的横径均明显大于椎弓根（P〈0．01）;经肋椎关节植入螺钉可提供的钉道长度明显优于椎弓根（P〈0．01）;经肋椎关节植入螺钉的e角普遍大于椎弓根钉（P〈0．01）。影像学结果显示：所有螺钉均处于椎肋关节中未进入椎管及突破外侧肋骨。结论从解剖学研究的角度看,经肋椎关节植入螺钉的安全性优于传统的椎弓根内固定。     

Ball tip技术置入中上胸椎椎弓根螺钉的准确性评价

 【目的】通过与徒手置钉术的比较来评价一种新的椎弓根置钉技术——Ball tip技术置入中上胸椎椎弓根钉的准确性。【方法】自2009年3月至2011年5月,对40例需行中上胸椎椎弓根钉内固定的患者,术中应用ball tip技术或徒手置钉技术置入椎弓根钉。椎弓根球形探针包括一个金属球端和一个具有良好弹性的金属柄,金属球端的直径分别有1.5、2.5、3.5mm三种。Ball tip技术要点：按标准椎弓根钉进钉点定位,高速磨钻钻孔去除皮质,将椎弓根球形探针按直径从小到大依次缓慢敲入椎弓根内直至达到椎体前方骨皮质。术后采用CT扫描评价椎弓根钉钉道情况。同样方法评价同期徒手置钉组。【结果】采用Ball tip技术共置入104枚椎弓根钉,传统徒手技术置入98枚。术后CT扫描显示Ball tip组胸椎椎弓根钉钉道准确率为84.6%,16枚（15.4%）螺钉出现置钉不良,其中3枚（2.9%）穿透椎弓根内侧骨皮质;6枚（5.8%）穿透椎弓根外侧骨皮质;7枚（6.7%）穿透椎体前壁骨皮质。徒手置钉组准确率为65.3%,共有34枚（34.7%）置钉不良螺钉,其中10枚（10.2%）穿透椎弓根内侧骨皮质;16枚（16.3%）穿透椎弓根外侧骨皮质;8枚（8.2%）穿透椎体前壁骨皮质。两组置钉准确率的差异具有统计学意义（P<0.01）,两组螺钉穿透椎弓根内侧、外侧骨皮质的差异具有统计学意义（P<0.05）。所有患者术中和术后均未出现神经、 血管和内脏损伤等并发症。【结论】与徒手置钉技术相比,Ball tip置钉技术,可更准确地置入中上胸椎椎弓根钉,减少因螺钉误置所导致的术后并发症。     

颈椎椎弓根形态个体化术前应用CT测量评价的临床意义

目的为有效施行颈椎椎弓根固定术,临床探讨术前采用CT测量的颈椎椎弓根置钉准确度以及置钉可行性。方法选取我院2014年2月-2015年7月期间96例行颈椎椎弓根固定患者,分为手测组、CT组,按入院时间进行分配,每组48例。CT组术前采用CT测量椎弓根高度、宽度确定置钉点,手测组采用手工测量椎弓根确定置钉点,观察置钉成功率、置钉准确度,记录椎弓根测量情况以及置钉时间、出血量。结果 CT组每钉置钉时间、出血量分别为(3.78±2.45)min、(307.42±179.47)ml明显少于手测组的(4.65±2.34)min以及(367.42±165.49)ml(P0.05);CT组与手测组在椎弓根高度、椎弓根宽度的C3-C6椎弓根参数测量值比较差别无意义(P0.05);CT组置钉准确度高达95.8%,出现全穿破率仅为4.2%,手测组为85.4%,且全穿破率高达14.6%,CT组较手测组置钉准确度高(P0.05)。结论临床采用CT测量所得椎弓根参数准确度高、临床置钉准确度高,且出血量少、置钉耗时少,可为临床个体化置钉提供较为准确的数据。     

腰椎椎弓根导针轴位透视监测的实验研究

目的通过术中对椎弓根多维透视结果进行比较,探索一种简洁易行的透视角度,减少术中椎弓根钉误置率.方法取8具成年人新鲜L1-5椎骨标本,随机建立偏内、偏外、居中3种模型.分别置入导针和椎弓根钉,依次透视侧位、正位、椎弓根轴位、导针轴位、椎弓根钉轴位.根据导针和椎弓根钉与椎弓根投影的相互位置关系判断导针和椎弓根钉位置.术后CT扫描椎弓根钉道,观察椎弓根内外侧皮质穿透情况.切除椎板直视观察结果作为金标准.结果正位透视准确率为34%.侧位透视不能判断偏内及偏外错误.椎弓根轴位透视误将4枚居中判为偏内,准确率为95%.导针轴位透视准确率为100%.结论导针轴位透视能准确判断椎弓根钉导针位置,可提高置钉准确率,减少椎弓根钉松动的人为因素.