3D打印导板在脊柱置钉中的应用研究进展

作为3D打印技术在脊柱外科应用的一部分,3D打印导板辅助脊柱外科置钉内固定技术正在得到越来越多的研究与应用。多项研究已经证实在颈椎、胸椎、腰椎以及复杂的寰枢椎和脊柱侧弯置钉时,3D打印导板辅助置钉均能够取得较高的准确率,降低螺钉穿破骨皮质的风险。与传统徒手置钉方法相比,应用导板辅助置钉更加准确。与最新的计算机导航置钉技术相比,导板技术在取得相似置钉精确度的同时,更加简单易操作,学习曲线短,不需要昂贵的计算机导航设备,应用更加广泛。现就3D打印导板在脊柱外科置钉内固定中的应用作一综述。     

个体化3D打印导向模板辅助胸腰椎椎弓根螺钉置入在强直性脊柱炎中的应用研究

目的 :评价个体化设计定制3D打印椎弓根螺钉导向模板辅助强直性脊柱炎(ankylosing spondylitis,AS患者胸腰椎椎弓根螺钉置入的准确性与安全性。方法:纳入2016年1月至2019年9月收治的8例AS患者的胸腰椎三维CT检查数据,利用Mimics 17.0、ideaMaker等计算机软件设计AS胸腰椎椎弓根螺钉导向模板,并利用3D打印机打印制作全部病例的实体模型(T_(10)-L_2),每例2份,分为导板辅助螺钉置入组(实验组)和徒手置钉组(对照组)。两组胸腰椎椎弓根螺钉均由同一名脊柱外科医师负责置入。根据术后CT影像结果评估两组椎弓根螺钉置入的准确性,并对螺钉置入情况进行分级:0级和1级螺钉为可接受置钉,2级和3级为不可接受置钉。同时比较术前3D打印软件虚拟设计的椎弓根螺钉的直径、长度、进钉点与后正中线的距离等指标与术中实际使用情况。结果:导板辅助螺钉置入组设计并打印出AS胸腰椎3D打印椎弓根螺钉导向模板23块,辅助置入螺钉46枚,可接受螺钉为44枚;置入单枚螺钉平均时间为(4.20±1.15) min,X线机透视次数为(5.00±1.25)次,置钉过程中螺钉和克氏针平均调整次数为(1.76±1.32)次。徒手置钉组使用传统影像学透视徒手方法置钉46枚,可接受螺钉30枚;置入单枚螺钉平均时间为(14.67±2.23) min,X线机透视次数为(14.46±2.21)次,螺钉和克氏针平均调整次数为(4.76±3.39)次。导板辅助螺钉置入组与徒手置钉组螺钉置入成功率分别为95.65%(44/46)和56.22%(30/46),差异有统计学意义(χ~2=13.538,P0.05);术前3D打印软件虚拟设计的椎弓根螺钉的直径、长度、进钉点与后正中线的距离,与术中实际使用情况差异无统计学意义(P0.05);导板辅助螺钉置入组置入单枚螺钉的时间、X线机透视次数及置钉过程中螺钉和克氏针平均调整次数均明显少于徒手置钉组(P0.01)。结论:3D打印技术定制个体化椎弓根螺钉导向模板显著提高了置钉的安全性、准确性及手术效率,尤其适用于AS合并骨折脱位等须行后路椎弓根螺钉固定的胸腰椎椎体。     

改良3D打印导板辅助颈椎椎弓根螺钉置钉的准确性研究

【摘要】 目的：探讨改良3D打印导板辅助颈椎椎弓根螺钉置钉的准确性。方法：回顾性分析2016年1月~2023年1月在我院行颈椎后路椎弓根螺钉内固定手术的60例患者的临床资料,其中男30例,女30例,年龄58.7±13.8岁（17~84岁）;根据颈椎后路手术是否使用导板辅助置钉分为导板组及徒手置钉组。导板组（30例）采用改良3D打印导板辅助颈椎椎弓根置钉,徒手置钉组（30例）采用角度尺辅助颈椎弓根置钉,两组患者年龄、性别、术前诊断无统计学差异（P＞0.05）。所有患者术后1周行颈椎CT扫描,按照Kaneyama标准判断椎弓根置钉准确性：0级,螺钉完全处于椎弓根中,没有穿破骨皮质;1级,螺钉穿破皮质<螺钉直径的50％;2级,螺钉穿破皮质≥螺钉直径的50％但没完全穿出;3级,完全穿出骨皮质。记录椎弓根置钉准确率（0级+1级螺钉占比）及因螺钉误置导致的血管神经损伤、切口感染、脑脊液漏、螺钉松动断裂等并发症。结果：导板组共置入椎弓根螺钉152枚,其中0级74枚,1级68枚,2级10枚,3级0枚,置钉准确率93.4%;徒手置钉组共置入椎弓根螺钉136枚,其中0级53枚,1级61枚,2级18枚,3级4枚,置钉准确率83.8%,导板组置钉准确率高于徒手置钉组（P＜0.05）。所有患者均未出现因椎弓根螺钉误置导致的血管神经损伤、切口感染及脑脊液漏等相关并发症。所有患者随访5～29个月（14.2±7.7个月）,无内固定松动、断裂等并发症。结论：改良3D打印导板辅助颈椎椎弓根置钉可提高置钉精准度。     

三维打印导板在腰椎后路椎弓根螺钉固定中的临床应用

目的 探讨三维打印导板在腰椎后路椎弓根螺钉固定中的应用价值.方法 选择2016年9月～2018年11月在本院接受后路腰椎椎弓根螺钉固定术的58例患者作为研究对象,根据治疗方法 分为传统组和3D组各29例,分别采用传统X线和3D打印导板辅助后路腰椎椎弓根螺钉内固定.观察两组患者术中出血量、置钉时间、X线透视次数、置钉准确性.结果 两组患者并发症发生率差异无统计学意义(P>0.05);3D组患者术中出血量、单枚螺钉置入时间和透视次数均少于传统组,差异均有统计学意义(P<0.05).3D组螺钉置入的优良率高于传统组,但差异无统计学意义(P>0.05).结论 3D打印导板可缩短手术时间,减少出血量,减少透视次数,但不能提高螺钉置入的准确率.     

3D打印导板辅助椎动脉高跨患者C2椎弓根螺钉置入的临床研究

目的:探讨在椎动脉高跨患者中3D打印导板辅助置入C2椎弓根螺钉的准确性和安全性。方法:回顾性分析2018年1月~2018年12月在我院行上颈椎后路内固定术的72例C2椎动脉高跨患者。根据辅助C2椎弓根螺钉置入方式的不同分为导板组(n=36例)和徒手组(n=36例)。两组患者年龄、性别、体重指数(BMI)、疾病类型等一般资料比较差异均无统计学意义(P>0.05)。记录并比较两组患者C2椎弓根螺钉置钉时间、手术时间、术中出血量、透视时间、术中出血量、置钉相关并发症、手术技术费用、住院时间以及术前、术后3d、术后6个月VAS评分、JOA评分。根据术后颈椎CT并按照Kawaguchi等提出的螺钉分级标准评估C2椎弓根螺钉置入准确率,并计算术前模拟置钉与术后实际置钉进钉角度在矢状面与横断面上的偏差。结果:导板组置钉时间、手术时间、透视时间明显优于徒手组(P<0.05),手术技术费用徒手组明显低于导板组(P<0.05)。两组术中出血量、住院时间无明显统计学差异(P>0.05),两组术后3d、术后6个月的VAS评分和JOA评分均较术前明显改善(P<0.05),组间比较无统计学差异(P>0.05)。导板组和徒手组分别置入C2椎弓根螺钉42枚、43枚;置钉准确率(0级+1级)分别为95.2%、72.1%。两组螺钉矢状面偏离角度分别为0.52°±0.42°、2.21°±0.69°,横断面偏离角度分别为0.51°±0.36°、2.16°±0.77°。导板组在置钉准确率、螺钉偏差角度均优于徒手组(P<0.05)。并发症情况:两组患者中共发生椎动脉损伤4例,其中导板组0例,徒手组4例,差异有统计学意义(P<0.05),所有患者术后均未发生螺钉松动、断钉断棒。结论:在椎动脉高跨患者中,3D打印导板和徒手技术辅助置钉可达到相似的临床疗效,但在置钉准确性和安全性方面,导板技术更占优势,同时它能显著缩短置钉时间、透视时间,降低手术并发症。     

3D打印导航模板引导双侧下颈椎前路椎弓根螺钉置钉的可行性

目的 :通过3D打印技术及骨科数字化技术制作下颈椎前路椎弓根螺钉置钉导航模板,观察模板辅助下置钉的准确性。方法:选取正常成人颈椎湿性标本10具(男、女各5具),将椎前软组织剔除,采用64排薄层CT扫描后获取其DICOM格式数据,导入Mimics软件后三维建模并为颈前路椎弓根螺钉选取理想钉道,设计建立螺钉导航模板后导出其STL数据,通过3D打印机快速打印成型。在导航导板引导下进行下颈椎前路椎弓根螺钉置钉,通过X线及CT评价螺钉的准确性。结果:10具尸体分别于C3~T1每节段置入2枚螺钉,共计120枚,根据螺钉的位置将其分为4级:0级,螺钉完全在椎弓根内,共115枚;1级,螺钉穿破椎弓根皮质,穿出部分小于螺钉直径的25%,1枚;2级,螺钉穿破椎弓根皮质,穿出部分为螺钉直径的25%~50%,3枚;3级,螺钉穿出椎弓根部分大于螺钉直径的50%,1枚。5枚穿破椎弓根皮质者2枚穿破椎弓根内侧皮质,3枚穿破外侧皮质,总体准确性为95.8%。结论:在湿性尸体颈椎标本上应用3D打印及骨科数字化技术制作的导航模板辅助行下颈椎前路椎弓根螺钉置钉的准确性高,为临床应用提供了依据。     

超声骨动力椎弓根寻路器的研制及其引导置钉的可行性研究

目的 :探讨自行研制的超声骨动力椎弓根寻路器辅助椎弓根螺钉置入的准确度及安全性。方法 :自行研制一种超声骨动力椎弓根寻路器,选择2具成年人脊柱标本(T1～L5节段),男性1具,年龄62岁,女性1具,年龄57岁,排除畸形、外伤及骨质疏松症等骨科疾病,将标本左侧椎弓根设置为实验组,通过超声骨动力椎弓根寻路器引导下置钉;右侧椎弓根设置为对照组,直视下徒手置钉。术中及术后即刻分别对两组标本行CT扫描,通过术中CT测量定位针长轴中线距椎弓根内外侧皮质距离;通过术后CT测量椎弓根螺钉穿出椎弓根皮质的距离并依据Neo法对置钉进行分级,统计两组精确置钉(0级置钉)、可接受置钉(Neo分级0级或1级)和不良置钉(Neo分级2级或3级)的情况。通过比较两组精确置钉率与不良置钉率上的整体差异,以及分别在上、中、下胸椎及腰椎的穿破皮质螺钉(Neo分级1、2、3级螺钉)的差异,评估两组间置钉精确性与安全性的差异。结果:两组各置入34枚定位针。实验组与对照组的定位针在上胸椎距皮质骨最小距离分别为2.77mm±1.05mm和0.59±2.31mm,中胸椎为1.97±1.01mm和0.98±1.70mm,下胸椎为3.02±0.93mm和2.53±0.83mm,腰椎为4.14±1.04mm和3.80±0.59mm。实验组有6枚定位针存在穿出的风险,对照组有14枚存在穿出的风险。在置钉方面,实验组与对照组的精确置钉率分别为82.36%和58.82%,可接受置钉率分别为97.06%和82.36%,不良置钉率分别为2.94%和17.64%。在所有穿破皮质螺钉中,实验组有1枚位于上胸椎(1级),2枚位于中胸椎(1级、2级各1枚),2枚位于下胸椎(1级2枚),1枚位于腰椎(1级);而对照组有6枚位于上胸椎(1级2枚、2级2枚、3级2枚),5枚位于中胸椎(1级3枚、2级1枚、3级1枚),3枚位于下胸椎(1级)。实验组在胸腰椎精确置钉率、可接受置钉率上明显高于对照组,而在不良置钉率上明显低于对照组,且差异均具有统计学意义(P0.05)。实验组与对照组在上胸椎节段(T1～T4)穿破皮质螺钉比率存在统计学差异(P0.05),而在中下胸椎及腰椎无统计学差异(P0.05)。结论:与徒手置钉相比,超声骨动力椎弓根寻路器引导下置钉在胸腰椎节段具有较高的准确性与安全性。     

3D打印颈椎前路椎弓根螺钉导板的准确性评估

[目的]设计制作3D打印颈椎前路椎弓根螺钉置钉导板,通过导板置钉并分析置钉的准确性。[方法]选取4具Sawbones颈椎骨模(C_1~C_7)进行CT扫描,三维重建颈椎椎体,通过计算机辅助设计在重建的3D模型上模拟出椎弓根螺钉的安全通道,并选取与相应椎体前方贴合的区域为导板基底部,将通道和导板基底部结合起来设计出合理的置钉导板,利用3D打印机制作出导板,导板辅助下在4具颈椎骨模(C_3~C_7)上置入20枚椎弓根螺钉。然后将带有螺钉的颈椎模型进行二次CT扫描,测量螺钉在椎弓根横断面和矢状面偏离中线的值,按照螺钉偏离椎弓根的绝对值及相对值两种评价方式评价置钉安全性。[结果]3D打印导板能成功辅助颈椎前路椎弓根螺钉的置入。螺钉在横断面向内、外偏移差异无统计学意义(P=0.688),在矢状面向上、下偏移差异无统计学意义(P=0.967)。按照螺钉偏离椎弓根的绝对值评价,位于安全位置的螺钉为19/20(95%);按照螺钉偏离椎弓根的相对值评价,不安全置钉数为0/20。[结论]使用3D打印导板辅助置入颈椎前路椎弓根螺钉,简易、实用、安全。该技术的临床应用值得深入研究。     

O型臂3D导航与徒手置钉在上颈椎椎弓根螺钉置入中的精确性比较

目的 :比较O型臂3D导航下C1、C2椎弓根螺钉置钉与徒手置钉精确性的差异,探讨O型臂导航在上颈椎椎弓根螺钉置钉中的应用价值。方法:纳入我院C1、C2椎弓根螺钉内固定患者62例,分为导航置钉组(A组)与徒手置钉组(B组)。A组:2014年1月~2015年3月,O型臂导航下行C1、C2后路椎弓根螺钉内固定术22例,男15例,女7例,年龄17~58岁(40.8±12.7岁);B组:2005年3月~2013年12月经徒手置入C1及C2椎弓根螺钉患者40例,男26例,女14例,年龄12~70岁(42.0±15.6岁)。所有患者术后均行颈椎CT平扫,按照Neo等的方法,根据椎弓根螺钉穿破椎弓根皮质的程度将置钉精确性分为四级(0级,螺钉完全处于椎弓根中,没有穿破骨皮质;1级,螺钉穿破皮质2mm,或小于螺钉直径的50%;2级,螺钉穿破皮质≥2mm且﹤4mm,或大于螺钉直径的50%但没完全穿出;3级,完全穿出皮质,螺钉处于椎管或椎动脉孔内),分别评估两组的置钉精确性并比较两组间的差异。结果:A组共置入C1、C2椎弓根螺钉67枚(C1 28枚,C2 39枚),其中0级60枚(89.6%),1级7枚(10.4%),无2级或3级不良置钉;B组共置入C1、C2椎弓根螺钉134枚(C1 64枚,C2 70枚),其中0级116枚(86.6%),1级13枚(9.7%),2级4枚(3.0%),3级1枚(0.7%)。两组间置钉精确性分级(P=0.49)及0级置钉率(P=0.55)均无统计学差异;A组未发现不良置钉,B组不良置钉发生率为3.7%,但组间无统计学差异(P=0.17)。两组均无置钉相关的血管、神经并发症发生。结论:术中O型臂导航与徒手置钉在上颈椎椎弓根螺钉置钉精确性上并无统计学差异,虽然导航能提供清晰的术中3D图像,但该技术未能完全避免置钉时螺钉轻度穿破骨皮质的发生,仍需提高术者与导航系统间的交互作用,完善操作技术,进一步提高置钉精确性。     

3D打印辅助与徒手上颈椎椎弓钉置入比较

[目的]比较3D打印技术辅助上颈椎椎弓根螺钉的置入与徒手置钉的早期临床效果。[方法] 2010年5月—2019年5月,对18例上颈椎畸形患者行寰枢或颈枕融合固定术,其中,10例采用3D打印导板引导上颈椎椎弓根置入10例,8例采用常规徒手置钉。比较两组早期临床与影像资料。[结果]所有患者均顺利完成手术,手术共置钉72枚,其中3D组40枚,徒手组32枚。3D组手术时间[(189.7±16.1) min vs (242.1±23.2) min, P<0.001]、术中失血量[(216.6±49.8) ml vs (385.0±23.5) ml, P<0.001]、平均每钉置入时间[(3.3±0.8) min vs (7.0±1.1) min, P<0.001]和透视次数[(8.7±1.1)次vs (30.0±3.3)次, P<0.001]均显著优于徒手组。影像方面,3D组术前模拟置钉和实际置钉在螺钉直径、长度以及与后正中线距离的差异均无统计学意义（P>0.05）。3D组置钉准确优良率显著高于徒手组（97.5%vs 81.3%, P<0.05）。[结论]与传...     

快速成形3D导板辅助下置入下颈椎前路椎弓根螺钉与徒手置钉的对比研究

目的:比较快速成形3D导板辅助下和徒手置入下颈椎前路椎弓根螺钉的位置差异,评价两种置钉方法的安全性.方法:8具甲醛浸泡后的成人下颈椎尸体标本,男4具,女4具;年龄32～65(40.3±5.6)岁,行X线片检查排除骨质破坏和畸形后,随机选取其中4具(3D导板组)行CT扫描后获得DICOM格式数据,导入Mimics软件建模...     

IsoC-3D实时定位导航系统引导植入腰椎椎弓根螺钉34例

目的:探讨IsoC-3D实时定位导航系统在腰椎椎弓根螺钉植入手术过程中的应用.方法:对腰椎滑脱、腰椎失稳、脊柱侧弯、腰椎骨折共34例在IsoC-3D实时定位导航系统引导下完成椎弓根螺钉的植入,共植入椎弓根螺钉132枚,术后进行X线平片及CT扫描掌握螺钉的方向和位置.结果:132枚椎弓根螺钉均未穿破椎弓根,椎弓根螺钉的方向、深度、位置均相当理想,全部病例无硬膜、神经根损伤.结论:IsoC-3D实时定位导航系统可以准确引导腰椎椎弓根螺钉的植入,避免椎弓根螺钉植入相关的并发症.     

三维CT模拟双通道螺钉置入同一腰椎椎弓根成功率的影响因素分析

目的通过三维CT模拟椎弓根螺钉(pedicle scrw,PS)和皮质骨通道螺钉(cortical bone trajectory,CBT)置入同一腰椎椎弓根,并分析置钉成功率的影响因素。方法应用Mimics 10.0软件重建49例病人腰椎三维图像,测量双侧L₁~L₅椎弓根直径(横径和纵径)。将横径及纵径各分为3档,横径:<8.0 mm、(8.0 mm,12.0 mm)、≥12.0 mm;纵径:<10.0 mm、(10.0 mm,14.0 mm)、≥14.0 mm。将年龄分为3档:<40岁、(40岁,60岁)、≥60岁。制定3种不同置钉方案:方案A,先置入PS并固定位置,后置入CBT;方案B,先置入CBT并固定位置,后置入PS;方案C,同时置入PS和CBT,并保持PS偏下、CBT偏上,各螺钉可自行调整进钉点及角度。每个椎弓根均进行3种方案的置钉,统计49例病人共计1470次置钉的成功次数。按照置钉是否成功进行分组,比较两组间横径、纵径、置钉方案的差异,并采用二元Logistic回归分析模型筛选置钉成功率的独立影响因素。结果1470次模拟置钉中,23例女性的置钉成功次数为159(159/690,23.04%),26例男性的置钉成功次数为407(407/780,52.18%)。年龄<40岁者17例,置钉成功次数为247(247/510,48.43%);年龄为(40岁,60岁)者19例,置钉成功次数为189(189/570,33.16%);年龄≥60岁者13例,置钉成功次数为130(130/390,33.33%)。单因素分析结果显示置钉成功组和置钉失败组间横径、纵径及置钉方案的差异均有统计学意义(P均<0.05)。二元Logistic回归分析结果显示椎弓根横径、纵径、置钉方案是置钉成功率的独立影响因素(P均<0.05)。结论本研究显示在腰椎同一节段同时置入PS和CBT具有可行性。椎弓根横径及纵径、置钉方案均可影响置钉成功率。双通道螺钉技术可以为脊柱后路内固定手术方式提供更多选择,扩展现有的腰椎内固定方式。     

胸腰椎椎弓根钉置入导向器的设计及应用实验

目的：设计一种新型椎弓根钉置入导向装置，以期减少椎弓根钉置入的失败几率。方法：术前CT扫描拟置钉椎体，确定椎弓根轴线。右侧以导向器辅助钻孔，左侧徒手钻孔。钻孔后孔内置克氏针，椎弓根环绕钢丝，摄正侧位X线片，评价其准确程度。结果：导向器组36个椎弓根有2个椎弓根(5．6％)穿破，徒手组36个椎弓根有8个椎弓根(22％)失败。经统计学处理显示，两组结果有显著性差异。结论：应用新型导向器，能明显降低下胸椎及腰椎椎弓根钉置入中的失败率。     

Accuracy and safety of pedicle screw placement in neuromuscular scoliosis with free-hand technique

It is a retrospective analytic study of 1,009 transpedicular screws (689 thoracic and 320 lumbosacral), inserted with free-hand technique in neuromuscular scoliosis using postoperative CT scan. The aim of paper was to determine the accuracy and safety of transpedicular screw placement with free-hand technique in neuromuscular scoliosis and to compare the accuracy at different levels in such population. All studies regarding accuracy and safety of pedicle screw in scoliosis represent idiopathic scoliosis using various techniques such as free-hand, navigation, image intensifier, etc., for screw insertion. Anatomies of vertebrae and pedicle are distorted in scoliosis, hence accurate and safe placement of pedicle screw is prerequisite for surgery. Between 2004 and 2006, 37 consecutive patients, average age 20 years (9–44 years), of neuromuscular scoliosis were operated with posterior pedicle screw fixation using free-hand technique. Accuracy of pedicle screws was studied on postoperative CT scan. Placement up to 2 mm medial side and 4 mm lateral side was considered within-safe zone. Of the 1,009 screws, 273 screws were displaced medially, laterally or on the anterior side showing that 73% screws (68% in thoracic and 82.5% in lumbar spine) were accurately placed within pedicle. Considering the safe zone, 93.3% (942/1009, 92.4% in thoracic and 95.3% in lumbar spine) of the screws were within the safe zone. Comparing accuracy according to severity of curve, accuracy was 75% in group 1 (curve <90°) and 69% in group 2 (curve >90°) with a safety of 94.8 and 91.2%, respectively (P = 0.35). Comparing the accuracy at different thoracic levels, it showed 67, 64 and 72% accuracy in upper, middle and lower thoracic levels with safety of 96.6, 89.2 and 93.1%, respectively, exhibiting no statistical significant difference (P = 0.17). Pedicle screw placement in neuromuscular scoliosis with free-hand technique is accurate and safe as other conditions.     

Pullout strength of misplaced pedicle screws in the thoracic and lumbar vertebrae - A cadaveric study

Background:

The objective of this cadaveric study was to analyze the effects of iatrogenic pedicle perforations from screw misplacement on the mean pullout strength of lower thoracic and lumbar pedicle screws. We also investigated the effect of bone mineral density (BMD), diameter of pedicle screws, and the region of spine on the pullout strength of pedicle screws.

Materials and Methods:

Sixty fresh human cadaveric vertebrae (D10–L2) were harvested. Dual-energy X-ray absorptiometry (DEXA) scan of vertebrae was done for BMD. Titanium pedicle screws of different diameters (5.2 and 6.2 mm) were inserted in the thoracic and lumbar segments after dividing the specimens into three groups: a) standard pedicle screw (no cortical perforation); b) screw with medial cortical perforation; and c) screw with lateral cortical perforation. Finally, pullout load of pedicle screws was recorded using INSTRON Universal Testing Machine.

Results:

Compared with standard placement, medially misplaced screws had 9.4% greater mean pullout strength and laterally misplaced screws had 47.3% lesser mean pullout strength. The pullout strength of the 6.2 mm pedicle screws was 33% greater than that of the 5.2 mm pedicle screws. The pullout load of pedicle screws in lumbar vertebra was 13.9% greater than that in the thoracic vertebra (P = 0.105), but it was not statistically significant. There was no significant difference between pullout loads of vertebra with different BMD (P = 0.901).

Conclusion:

The mean pullout strength was less with lateral misplaced pedicle screws while medial misplaced pedicle screw had more pullout strength. The pullout load of 6.2 mm screws was greater than that of 5.2 mm pedicle screws. No significant correlation was found between bone mineral densities and the pullout strength of vertebra. Similarly, the pullout load of screw placed in thoracic and lumbar vertebrae was not significantly different.     

快速成型模型佐助胸腰椎椎弓根置钉的研究

目的 探讨快速成型技术佐助胸腰椎椎弓根螺钉置入的准确性和可靠性.方法 将患者分成两组,快速成型组26例,传统手法置钉组26例,由同一位医师分别采用快速成型模型佐助置钉法和传统手法置钉进行胸腰椎椎弓根螺钉置入.术后CT扫描比较两种方法的置钉准确性.结果 快速成型模型佐助置钉156枚,其中3枚穿破皮质,成功率98.08％,绝对风险率0.64％;传统手法置钉121枚,11枚穿破皮质,成功率90.91％,绝对风险率4.13％.两组病例均未出现神经血管损伤并发症,快速成型佐助置钉法准确率明显高于传统手法置钉,安全性提高,差异具有统计学意义(P＜0.05).结论 快速成型模型佐助胸腰椎椎弓根置钉,可提高准确率和安全性,操作简单,符合个体化置钉,为胸腰椎椎弓根螺钉置入提供一种新方法.     

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.     

Computer tomography assessment of pedicle screw placement in lumbar and sacral spine: comparison between free-hand and O-arm based navigation techniques

Transpedicular screw fixation has been accepted worldwide since Harrington et al. first placed pedicle screws through the isthmus. In vivo and in vitro studies indicated that pedicle screw insertion accuracy could be significantly improved with image-assisted systems compared with conventional approaches. The O-arm is a new generation intraoperative imaging system designed without compromise to address the needs of a modern OR like no other system currently available. The aim of our study was to check the accuracy of O-arm based and S7-navigated pedicle screw implants in comparison to free-hand technique described by Roy-Camille at the lumbar and sacral spine using CT scans. The material of this study was divided into two groups, free-hand group (group I) (30 patients; 152 screws) and O-arm group (37 patients; 187 screws). The patients were operated upon from January to September 2009. Screw implantation was performed during PLIF or TLIF mainly for spondylolisthesis, osteochondritis and post-laminectomy syndrome. The accuracy rate in our work was 94.1% in the free-hand group compared to 99% in the O-arm navigated group. Thus it was concluded that free-hand technique will only be safe and accurate when it is in the hands of an experienced surgeon and the accuracy of screw placement with O-arm can reach 100%.     

导向器结合钉道内壁探查法在下颈椎椎弓根螺钉置入中应用研究

目的:探讨导向器结合钉道内壁探查法置入下颈椎弓根螺钉的技巧并评价其准确性及安全性。方法:2014年1月至2016年10月采用自行设计带角度仪导向器结合钉道内壁探查法对11例患者置入下颈椎椎弓根螺钉,其中男7例,女4例;年龄32~63岁,平均48.1岁;脊髓型颈椎病4例,颈椎骨折脱位4例,无骨折脱位颈脊髓损伤1例,寰枢椎骨折脱位2例。术前CT测量出目标椎弓根直径、理想进钉点及矢状面夹角和横断面内倾角。术中使用自行设计带角度仪导向器严格控制进钉角度,结合探查钉道内壁作为安全置钉标志。术后观察患者有无脊髓及椎动脉损伤表现,复查CT评价椎弓根螺钉位置,并将螺钉准确性进行分级,计算螺钉优良率。结果:11例患者共置入71枚下颈椎弓根螺钉,均未出现手术所导致的脊髓及神经根损伤症状,亦无椎动脉损伤症状。术后CT评估螺钉位置并进行分级:0级52枚,1级13枚,2级4枚,3级2枚。螺钉位置良好率91%。6枚误置螺钉,内壁穿破4枚,2枚穿破外壁。结论:钉道内壁探查法置入下颈椎弓根螺钉安全可靠,但有一定的学习曲线。术中探查出钉道内壁及使用角度仪导向器控制进钉角度是置钉关键。