颅颈交界区螺钉-钛棒(板)内固定技术的临床应用

目的 探讨螺钉-钛棒(板)内固定技术治疗颅颈交界区不稳定的临床经验.方法 27例颅颈交界区不稳定患者(先天性寰枢关节脱位21例、颅底凹陷症经口齿状突切除致寰枢关节脱位1例、外伤致寰枢关节脱位1例、经口斜坡脊索瘤切除致寰枢关节脱位3例和椎管内神经纤维瘤病致寰枕关节破坏1例),手术前日本整形外科协会(JOA)评分1～13分,平均(7.45±1.62)分,施行枕骨钉或寰椎侧块-枢椎椎弓根螺钉内固定术,并通过螺钉间撑开技术使寰枢关节复位.根据手术后JOA评分和影像学改善程度,评价手术疗效.结果 27例患者中除1例手术后临床症状无明显变化,余26例均明显改善.手术后2周CT检查椎体间融合良好,仅2例(2枚)枢椎椎弓根螺钉穿破骨皮质,但未造成血管损伤或神经压迫,其余螺钉位置良好.随访3～36个月,平均10.50个月.手术后3个月,患者JOA评分1～13分,平均(13.26±1.02)分,与手术前比较,差异具有统计学意义(t=24.210,P=0.001);平均改善率为(60±12)%.结论 枕骨钉或寰椎侧块.枢椎椎弓根螺钉内固定术治疗颅颈交界区不稳定安全有效.     

经椎弓根钉板内固定治疗上颈椎疾患的个性化设计及临床应用

背景：上颈椎疾患从后路行椎弓根固定在国内个别大型医院虽已相继开展,但该手术仍为颈椎外科高难度手术。为了将手术风险降至最低,作者设计了一套个体化手术方案,并结合自行研制的椎弓根定位导向器行术中精确定位置钉,经检索相关数据库在国内未见报道。 目的：提高内固定置钉的一次成功率及植入体的生物力学效应,利用辅助检查资料为寰枢椎椎弓根螺钉的置钉制定简单、实用的个性化方案。 方法：选择2002-01/2006-09解放军第二五一医院骨科患者31例。术中采用自制的寰枢椎定位导向器,根据寰枢椎椎弓根X射线-CT个体化测量的结果,确定进钉点、入钉的角度,选择直径及长度合适的椎弓根螺钉置入。寰椎椎弓根进钉点：左侧(19.93± 1.32) mm,右侧(19.16±1.30) mm,寰椎椎弓根向内侧进钉角度：左侧(23.72±2.09)°,右侧(23.35±1.91)°,寰椎向头侧进钉角度(9.00±1.20)°。枢椎椎弓根进钉点：左侧(13.14±0.82) mm,右侧(13.85±0.79) mm。 枢椎椎弓根向内侧进钉角度：左侧(24.52±1.26)°,右侧(20.42±1.42)°,枢椎向头侧进钉角度(25.00±3.00)°。 结果与结论：①31例患者置入124枚椎弓根螺钉,1次置钉成功122枚螺钉,正确率为98.39%,有2枚因内倾角偏差不够,穿破椎弓根的外侧骨皮质而改为2次定位。②2例术后出现枕大神经痛,经对症治疗1个月后痊愈,2例螺钉穿破寰椎左侧椎弓根外侧壁,未发现脊髓、椎动脉损伤。③所有患者X射线平片显示寰椎完全复位,枢椎齿状突骨折处对位良好。CT片示螺钉与椎动脉的脊髓位置关系良好。④平均随访10.5个月,均获得骨性融合,未发现钉板断裂材料反应。无炎症、排异等宿主反应。⑤按JOA评分标准,优16例,良12例,可2例,差1例,优良率90%。提示从生物力学角度实施植入体置入,可提高寰枢椎椎弓根螺钉的置入成功率。     

自发性寰枢关节脱位后路复位内固定术中枢椎椎弓根螺钉置入不能时的备选方法

目的探讨自发性寰枢关节脱位后路内固定过程中枢椎椎弓根螺钉置入不能时,其他备选螺钉内固定技术的安全性及有效性。方法对贵州省人民医院神经外科未采用枢椎椎弓根螺钉内固定治疗的11例自发性寰枢关节脱位患者的临床资料进行回顾性分析。在枢椎椎弓根螺钉置入不能时,采用枢椎椎板螺钉、峡部螺钉、枢椎下关节突螺钉及延长固定节段至C3侧块螺钉来增加稳定性的方法。手术前后分别行CT及MRI检查,评价脊髓受压程度、脱位复位情况、螺钉位置、骨融合情况;通过比较术前、术后日本骨科协会(JOA)评分来评价疗效。结果 11例患者均为枢椎椎弓根置钉不能,改用备选方法置钉,全部行枕颈钉棒内固定。共置入枢椎椎板锣钉14枚,枢椎峡部螺钉5枚,枢椎下关节突螺钉1枚,延长固定节段至C3侧块螺钉4枚。术中均未发生椎动脉和脊髓神经根损伤。11例患者的寰枢关节脱位均得到不同程度的复位,随访中无患者出现螺钉松动、滑脱、断钉及复位丢失等情况,JOA评分为显著增加。结论对自发性寰枢关节脱位后路内固定过程中枢椎椎弓根螺钉置入不能时,可根据情况,个性化选用枢椎椎板螺钉、峡部螺钉、枢椎下关节突螺钉及延长固定节段至C3侧块螺钉的方法来固定,是可行且有效的。     

椎弓根钉棒系统治疗不稳定性Jefferson骨折的生物力学分析

背景：目前后路寰枢椎椎弓根螺钉有取代Magerl技术趋势,成为治疗寰枢椎不稳的新标准术式。 目的：评价单、双侧椎弓根钉棒系统治疗不稳定性Jefferson骨折的力学稳定性,为临床应用提供实验依据。 方法：在6具完整枕骨颈椎(C0~4)湿润标本切断寰椎前后弓与侧块的联接部位,并切断寰椎横韧带,制成不稳定性 Jefferson骨折模型,分别安装单侧寰枢椎椎弓根螺钉系统和双侧寰枢椎椎弓根螺钉系统,通过摄像记录在1.53 N•m载荷下C1~2的三维运动,测定正常组、骨折模型组及各内固定组的三维运动范围,评价其重建寰枢椎即时稳定性的效果。 结果与结论：在屈伸、侧屈及轴向旋转的运动中,单侧寰枢椎椎弓根螺钉系统组的三维运动范围均明显大于双侧寰枢椎椎弓根钉棒系统组(P < 0.05)。提示在治疗不稳定性 Jefferson骨折时,双侧寰枢椎椎弓根钉棒系统内固定治疗稳定性好;单侧寰枢椎椎弓根螺钉系统固定效果不佳,尤其是抗旋转能力差,不能满足增强稳定性、植骨融合的要求,应尽量避免单独使用。     

寰枢椎定位导向内固定置钉点、角度、直径及长度的个性化设计

目的：为提高内固定置钉的一次成功率，利用辅助检查资料为寰枢椎椎弓根螺钉的置钉制定简单、实用的个性化方案。 方法：选择2002-01/2006-09解放军第二五一医院骨科患者31例。术中采用自制的寰枢椎定位导向器，根据寰枢椎椎弓根X射线-CT个体化测量的结果，确定进钉点、入钉的角度，选择直径及长度合适的椎弓根螺钉置入。寰椎椎弓根进钉点：左侧（19.93±1.32）mm，右侧（19.16±1.30）mm，寰椎椎弓根向内侧进钉角度：左侧（23.72±2.09）°，右侧（23.35±1.91）°，寰椎向头侧进钉角度（9.00±1.20）°。枢椎椎弓根进钉点：左侧（13.14±0.82）mm，右侧（13.85±0.79）mm。 枢椎椎弓根向内侧进钉角度：左侧（24.52±1.26）°右侧（20.42±1.42）°，枢椎向头侧进钉角度（25.00±3.00）°。 结果：①对31例患者置入124枚椎弓根螺钉，1次置钉成功122枚螺钉，正确率为98.39%，有2枚因内倾角偏差不够，穿破椎弓根的外侧骨皮质而改为2次定位。②2例术后出现枕大神经痛，经对症治疗1个月后痊愈，2例螺钉穿破寰椎左侧椎弓根外侧壁，未发现脊髓、椎动脉损伤。③所有患者X射线片显示寰椎完全复位，枢椎齿状突骨折处对位良好。CT片示螺钉与椎动脉的脊髓位置关系良好。④平均随访10.5个月，均获得骨性融合，未发现钉板断裂材料反应。⑤按JOA评分标准，优16例，良12例，可2例，差1例，优良率90.32%。 结论：X射线-CT个性化设计方案可提高寰枢椎椎弓根螺钉的置入成功率。     

齿状突游离所致寰枢椎脱位的外科治疗

目的 总结齿状突游离小骨导致寰枢椎脱位患者的临床治疗经验。方法 回顾分析2004年10月至2010年3月宣武医院神经外科治疗的10例齿状突游离小骨所致寰枢椎脱位患者的临床经验。采用颈后路寰枢椎椎弓根螺钉或枕颈螺钉内固定植骨融合术进行治疗,术前、术后采用JOA评分评价手术疗效。结果 手术平均时间3h,未发生与手术相关并发症,术后8例患者症状改善,2例患者症状无明显变化,术前与术后3个月JOA评分差异有统计学意义。术后3个月复查寰枢椎均达到复位和骨性融合。结论 采用寰枢椎椎弓根螺钉或枕颈螺钉内固定技术治疗齿状突小骨可以有效地进行寰枢椎之间的融合,改善齿状突小骨导致的神经功能症状。     

术中CT导航在先天性颅颈畸形后路固定中的应用

目的 探讨术中CT与导航系统在先天性颅颈交界区畸形后路固定手术中的应用价值.方法 本组23例患者畸形复杂,男11例,女12例,年龄19～52岁,平均33.5岁.其中3例外院行单纯后颅窝减压术,采用术中CT导航下后路修补枕颈固定术,12例经口齿状突磨除术后,行二期术中CT导航下后路固定术,单纯行术中CT导航下后路减压固定术8例.结果 导航下后路寰椎侧块、枢椎椎弓根螺钉固定7例,经寰枢关节螺钉固定6例,枕颈钉棒系统固定10例,导航验证准确度平均为1.8 mm(0.6 ～2.2 mm).术中发现2例椎弓根螺钉位置不佳,术中调整后CT验证螺钉位置满意.根据术前及术后6个月Nurick分级,21例(91％)患者症状改善1级以上,2例(9％)患者症状无明显改善.本组病例无术中椎动脉及神经功能损伤等并发症.结论 术中CT结合导航系统可以术中及时评价寰枢关节复位情况和植入螺钉的位置及深度,有效地避免了患者二次手术的风险;对于提高手术定位精度、优化手术路径及提高手术成功率等具有重要意义.     

Goel技术治疗合并寰枕融合的寰枢椎脱位

目的 探讨应用Goel技术(即应用C1侧块-C2椎弓峡部螺钉-棒内固定器械行C1～2侧块关节复位、固定和植骨融合)手术治疗合并寰枕融合的寰枢椎脱位的可行性及临床疗效.方法 回顾性分析138例2009年11月至2013年3月间解放军总医院神经外科收治并手术的颅底凹陷合并寰枢椎关节脱位患者的临床资料.男61例,女77例;年龄7～65岁,平均37.3岁.所有病例均采用经寰椎侧块螺钉和枢椎椎弓峡部螺钉或下关节突螺钉棒内固定系统行C1～2侧块关节复位固定,于髂后上嵴取松质骨颗粒植骨融合.结果 138例中136例获得满意临床治疗效果,2例出现严重并发症,其中1例死亡.根据出院前颈椎3D-CT结果评判,54例完全复位,83例部分复位.87例得到3个月以上时间随访,未出现断钉、断棒现象,其中85例内固定稳固,植骨愈合,2例随访时发现内固定松动做了翻修手术,重新植骨融合.87例随访患者功能评价(Odom评级):优35例,良50例,可2例,差0例.结论 应用Goel内固定技术对寰枢椎侧块关节复位、固定及植骨融合治疗畸形寰枢椎脱位安全可行,疗效满意.     

应用C1-2螺钉棒系统行后路复位、固定和融合治疗合并寰-枢椎脱位的颅底凹陷症

目的探讨应用C1-2螺钉棒内固定系统行后路复位、固定和融合治疗寰枢椎脱位的手术疗效。方法 2013年4月至2013年10月,对30例我科收治的合并寰枢椎脱位的颅底凹陷症患者采用寰椎侧块螺钉和枢椎椎弓根峡部螺钉(或下关节突螺钉、颈3椎弓根螺钉)棒内固定系统进行复位、固定并取髂后上嵴松质骨植骨融合。通过术后3D-CT评判复位程度,JOA评分评判临床疗效,并探讨影响手术效果的因素。结果 30例患者中26例达到完全复位,4例为部分复位。其中25例完成了3个月以上随访,CT显示植骨愈合良好,未出现植骨的吸收及内固定的松动。结论 C1-2椎弓根钉棒内固定系统对治疗合并寰枢椎脱位的颅颈交界区畸形可以获得满意的疗效,安全可行。     

内侧"in-out-in"枢椎椎弓根螺钉在上颈椎手术中的应用研究

目的探讨上颈椎手术中应用内侧"in-out-in"枢椎椎弓根螺钉治疗寰枢椎脱位或不稳的临床疗效。方法选择河南省人民医院脊柱脊髓科自2017年1月至2020年1月收治的31例寰枢椎脱位或不稳患者进行研究, 其中17例患者单侧椎弓根狭窄(优势椎动脉15例, 单侧椎动脉2例), 于该侧置入内侧"in-out-in"枢椎椎弓根螺钉, 另一侧置入常规枢椎椎弓根螺钉;14例患者双侧椎弓根狭窄(优势椎动脉13例, 单侧椎动脉1例), 于优势或单侧椎动脉侧置入内侧"in-out-in"枢椎椎弓根螺钉, 另一侧置入内侧或外侧"in-out-in"枢椎椎弓根螺钉。术前及术后5 d、3个月、6个月、12个月时对所有患者行X线、CT、MRI等检查, 对比观察植骨融合情况;收集术前及术后7 d、3个月、6个月、末次随访时所有患者的视觉模拟评分(VAS)、日本矫形外科协会(JOA)评分, 对比评估患者的临床疗效。结果本组患者的手术时间为(164.2±28.3) min(136～224 min), 术中出血量为(283.6±74.5) mL(180～560 mL), 且均无脊髓血管损伤及其他严重并发症发生。术后2例...     

The Use of Pedicle Screw-Rod System for the Posterior Fixation in Cervico-Thoracic Junction

Objective

In cervico-thoracic junction (CTJ), the use of strong fixation device such as pedicle screw-rod system is often required. Purpose of this study is to analyze the anatomical features of C7 and T1 pedicles related to screw insertion and to evaluate the safety of pedicle screw insertion at these levels.

Methods

Nineteen patients underwent posterior CTJ fixation with C7 and/or T1 included in fixation levels. Seventeen patients had tumorous conditions and two with post-laminectomy kyphosis. The anatomical features were analyzed for C7 and T1 pedicles in 19 patients using computerized tomography (CT). Pedicle screw and rod fixation system was used in 16 patients. Pedicle violation by screws was evaluated with postoperative CT scan.

Results

The mean values of the width, height, stable depth, safety angle, transverse angle, and sagittal angle of C7 pedicles were 6.9 ± 1.34 mm, 8.23 ± 1.18 mm, 30.93 ± 4.65 mm, 26.42 ± 7.91 degrees, 25.9 ± 4.83 degrees, and 10.6 ± 3.39 degrees. At T1 pedicles, anatomic parameters were similar to those of C7. The pedicle violation revealed that 64.1% showed grade I violation and 35.9% showed grade II violation, overall. As for C7 pedicle screw insertion, grade I was 61.5% and grade II 38.5%. At T1 level, grade I was 65.0% and grade II 35.0%. There was no significant difference in violation rate between the whole group, C7, and T1 group.

Conclusion

C7 pedicles can withstand pedicle screw insertion. C7 pedicle and T1 pedicle are anatomically very similar. With the use of adequate fluoroscopic oblique view, pedicle screw can be safely inserted at C7 and T1 levels.     

A Computed Tomography-Based Anatomic Comparison of Three Different Types of C7 Posterior Fixation Techniques : Pedicle, Intralaminar, and Lateral Mass Screws

Objective

The intralaminar screw (ILS) fixation technique offers an alternative to pedicle screw (PS) and lateral mass screw (LMS) fixation in the C7 spine. Although cadaveric studies have described the anatomy of the pedicles, laminae, and lateral masses at C7, 3-dimensional computed tomography (CT) imaging is the modality of choice for pre-surgical planning. In this study, the goal was to determine the anatomical parameter and optimal screw trajectory for ILS placement at C7, and to compare this information to PS and LMS placement in the C7 spine as determined by CT evaluation.

Methods

A total of 120 patients (60 men and 60 women) with an average age of 51.7±13.6 years were selected by retrospective review of a trauma registry database over a 2-year period. Patients were included in the study if they were older than 15 years of age, had standardized axial bone-window CT imaging at C7, and had no evidence of spinal trauma. For each lamina and pedicle, width (outer cortical and inner cancellous), maximal screw length, and optimal screw trajectory were measured, and the maximal screw length of the lateral mass were measured using m-view 5.4 software. Statistical analysis was performed using Student''s t-test.

Results

At C7, the maximal PS length was significantly greater than the ILS and LMS length (PS, 33.9±3.1 mm; ILS, 30.8±3.1 mm; LMS, 10.6±1.3; p<0.01). When the outer cortical and inner cancellous width was compared between the pedicle and lamina, the mean pedicle outer cortical width at C7 was wider than the lamina by an average of 0.6 mm (pedicle, 6.8±1.2 mm; lamina, 6.2±1.2 mm; p<0.01). At C7, 95.8% of the laminae measured accepted a 4.0-mm screw with a 1.0 mm of clearance, compared with 99.2% of pedicle. Of the laminae measured, 99.2% accepted a 3.5-mm screw with a 1.0 mm clearance, compared with 100% of the pedicle. When the outer cortical and inner cancellous height was compared between pedicle and lamina, the mean lamina outer cortical height at C7 was wider than the pedicle by an average of 9.9 mm (lamina, 18.6±2.0 mm; pedicle, 8.7±1.3 mm; p<0.01). The ideal screw trajectory at C7 was also measured (47.8±4.8° for ILS and 35.1±8.1° for PS).

Conclusion

Although pedicle screw fixation is the most ideal instrumentation method for C7 fixation with respect to length and cortical diameter, anatomical aspect of C7 lamina is affordable to place screw. Therefore, the C7 intralaminar screw could be an alternative fixation technique with few anatomic limitations in the cases when C7 pedicle screw fixation is not favorable. However, anatomical variations in the length and width must be considered when placing an intralaminar or pedicle screw at C7.     

Feasibility of Bilateral Crossing C7 Intralaminar Screws: A Cadaveric Study

Objective

When the pedicle screw insertion technique is failed or not applicable, C7 intralaminar screw insertion method has been used as an alternative or salvage fixation method recently. However, profound understanding of anatomy is required for safe application of the bilaterally crossing laminar screw at C7 in clinic. In this cadaveric study, we evaluated the anatomic feasibility of the bilateral crossing intralaminar screw insertion and especially focused on determination of proper screw entry point.

Methods

The C7 vertebrae from 18 adult specimens were studied. Morphometric measurements of the mid-laminar height, the minimum laminar thickness, the maximal screw length, and spino-laminar angle were performed and cross-sectioned vertically at the screw entry point (spino-laminar junction). The sectioned surface was equally divided into 3 parts and maximal thickness and surface area of the parts were measured. All measurements were obtained bilaterally.

Results

The mean mid-laminar height was 13.7 mm, mean minimal laminar thickness was 6.6 mm, mean maximal screw length was 24.6 mm, and mean spinolaminar angle was 50.8±4.7°. Based on the measured laminar thickness, the feasibility of 3.5 mm diameter intralaminar screw application was 83.3% (30 sides laminae out of total 36) when assuming a tolerance of 1 mm on each side. Cross-sectional measurement results showed that the mean maximal thickness of upper, middle, and lower thirds was 5.0 mm, 7.5 mm, and 7.3 mm, respectively, and mean surface area for each part was 21.2 mm², 46.8 mm², and 34.7 mm², respectively. Fourteen (38.9%) sides of laminae would be feasible for 3.5 mm intralaminar screw insertion when upper thirds of C7 spino-laminar junction is the screw entry point. In case of middle and lower thirds of C7 spino-laminar junction, 32 (88.9%) and 28 (77.8%) sides of laminae were feasible for 3.5 mm screw insertion, respectively.

Conclusion

The vertical cross-sectioned area of middle thirds at C7 spinolaminar junction was the largest area and 3.5 mm screw can be accommodated with 77.8% of feasibility when lower thirds were the screw entry point. Thus, selection of middle and lower thirds for each side of screw entry point in spino-laminar junction would be the safest way to place bilateral crossing laminar screw within the entire lamina. This anatomic study result will help surgeons to place the screw safely and accurately.     

先天性颈椎2-3融合的形态特点与内固定技术解剖适用性

目的 研究先天性颈椎2-3(C2-3)融合的形态特点,为外科内固定技术的解剖学适用性提供依据.方法 17例先天性C2-3融合连续病例,经螺旋CT扫描后,三维重建C2-3结构,分析其形态特点,测量C2关节间部和C3椎弓根大小,评估螺钉置入的可行性.结果 典型的先天性C2-3融合的典型特征为椎体、椎板、棘突、关节突完全融合,而横突和椎弓根未融合;不完全的椎体、椎板、棘突和关节突融合可见于少数病例.本组17例,不适合3.5 mm螺钉置入者分别见于1例两侧C2关节间部狭窄;3例两侧C3椎弓根狭窄;4例一侧C2关切节间部狭窄;7例一侧C3椎弓根狭窄.结论 尽管先天性C2-3融合解剖形态与正常C2-3结构相异甚大,多数病例应用螺钉内固定技术仍然是可行的.     

Unilateral C1 Lateral Mass and C2 Pedicle Screw Fixation for Atlantoaxial Instability in Rheumatoid Arthritis Patients: Comparison with the Bilateral Method

Objective

Bilateral C1 lateral mass and C2 pedicle screw fixation (C1LM-C2P) is an ideal technique for correcting atlantoaxial instability (AAI). However, the inevitable situation of vertebral artery injury or unfavorable bone structure may necessitate the use of unilateral C1LM-C2P. This study compares the fusion rates of the C1 lateral mass and C2 pedicle screw in the unilateral and bilateral methods.

Methods

Over five years, C1LM-C2P was performed in 25 patients with AAI in our institute. Preoperative studies including cervical X-ray, three-dimensional computed tomography (CT), CT angiogram, and magnetic resonance imaging were performed. To evaluate bony fusion, measurements of the atlanto-dental interval (ADI) and CT scans were performed in the preoperative period, immediate postoperative period, and postoperatively at 1, 3, 6, and 12 months.

Results

Unilateral C1LM-C2P was performed in 11 patients (44%). The need to perform unilateral C1LM-C2P was due to anomalous course of the vertebral artery in eight patients (73%) and severe degenerative arthritis in three patients (27%). The mean ADI in the bilateral group was 2.09 mm in the immediate postoperative period and 1.75 mm in 12-months postoperatively. The mean ADI in the unilateral group was 1.82 mm in the immediate postoperative period and 1.91 mm in 12-months postoperatively. Comparison of ADI measurements showed no significant differences in either group (p=0.893), and the fusion rate was 100% in both groups.

Conclusion

Although bilateral C1LM-C2P is effective for AAI from a biomechanical perspective, unilateral screw fixation is a useful alternative in patients with anatomical variations.     

成人颈椎椎弓根螺钉在儿童腰椎应用的可行性*

背景：由于1~3岁幼年儿童椎体发育未完全成熟,各种解剖径线相对较成人小得多,尚无幼儿专用的椎弓根螺钉固定器械,现有能够利用的直径最小的椎弓根螺钉是用于成人颈椎侧块或椎弓根固定的钉棒系统。 目的：观察将成人颈椎椎弓根螺钉应用到成年猪颈椎与幼猪腰椎固定后的生物力学对比。 方法：将6具完整新鲜成年猪颈段C3~C6脊椎标本和6具完整8周龄新鲜幼猪腰段脊柱标本自椎间盘及关节处离断,游离成单个椎体,共54个椎体108侧椎弓根。按照标准操作将成人颈椎椎弓根螺钉分别安置在成年猪颈椎标本和幼猪腰椎标本的椎弓根上,应用生物力学方法测试螺钉的最大轴向拔出力。 结果与结论：颈椎标本最大轴向拔出力高于腰椎标本,但差异无显著性意义(P > 0.05);L1椎弓根螺钉的拔出力均值明显小于L3椎弓根螺钉的拔出力均值(P < 0.05);C5椎弓根螺钉的拔出力均值明显大于C3椎弓根螺钉的拔出力均值(P < 0.05);颈椎和腰椎标的骨密度差异有显著性意义(P < 0.01),椎体椎弓根力学数值与椎体骨密度之间存在线性正相关。说明取得了成人颈椎椎弓根螺钉在轴向拉力方面适应于幼儿腰椎的初步实验依据。     

Inferolateral Entry Point for C2 Pedicle Screw Fixation in High Cervical Lesions

Objective

The purpose of this retrospective study was to evaluate the efficacy and safety of atlantoaxial stabilization using a new entry point for C2 pedicle screw fixation.

Methods

Data were collected from 44 patients undergoing posterior C1 lateral mass screw and C2 screw fixation. The 20 cases were approached by the Harms entry point, 21 by the inferolateral point, and three by pars screw. The new inferolateral entry point of the C2 pedicle was located about 3-5 mm medial to the lateral border of the C2 lateral mass and 5-7 mm superior to the inferior border of the C2-3 facet joint. The screw was inserted at an angle 30° to 45° toward the midline in the transverse plane and 40° to 50° cephalad in the sagittal plane. Patients received followed-up with clinical examinations, radiographs and/or CT scans.

Results

There were 28 males and 16 females. No neurological deterioration or vertebral artery injuries were observed. Five cases showed malpositioned screws (2.84%), with four of the screws showing cortical breaches of the transverse foramen. There were no clinical consequences for these five patients. One screw in the C1 lateral mass had a medial cortical breach. None of the screws were malpositioned in patients treated using the new entry point. There was a significant relationship between two group (p=0.036).

Conclusion

Posterior C1-2 screw fixation can be performed safely using the new inferolateral entry point for C2 pedicle screw fixation for the treatment of high cervical lesions.     

多层螺旋CT三维重建国人下颈椎椎弓根的临床解剖学意义

背景：因颈椎解剖结构复杂以及个体化差异较大,导致颈椎弓根钉置入内固定技术应用受到很大限制。 目的：应用螺旋CT三维重建国人的下颈椎椎弓根,并对重建图像进行测量评估。 方法：对60例需行颈椎CT扫描的患者C3~C7进行颈椎CT扫描,使用Syngo应用软件对原始CT图像进行所需面的重建,测量CT重建后的椎弓根各项指标。 结果与结论：颈椎绝大部分椎弓根峡部的宽度小于高度,男性高度和宽度C4~C7逐渐增大,女性则从C3开始逐渐增大。C3~C7椎弓根侧块投射点到上关节突下缘的距离并无规律性,而到侧块外缘的距离从头端到尾端是不断增大的。男性与女性的椎弓根水平角在C7均最小。结果提示,国人女性患者的C3及C4椎体行经颈椎椎弓根内固定应谨慎,大部分国人的C5到C7椎体是适合行椎弓根内固定的,但考虑到颈椎弓根个体的差异较大,内固定前颈椎弓根的CT扫描及重建后的评估是必要的。     

Neurovascular complications of cervical pedicle screw fixation

We rarely use the cervical transpedicular fixation (CPF) technique in the neurosurgery departments of the authors' institutions because the pedicle is thin and there is a risk of neurovascular damage. In this study we investigated postoperative neurovascular injury caused by the transpedicular screws of 210 pedicles in 45 patients on whom we performed CPF for various cervical pathologies. Fixation was performed between C3 and C7, and the iliac crest and lamina were used as autografts for fusion. In 205 of 210 pedicles (97.6%), the screws were in the correct position, while a non-critical lateral orientation was detected in three pedicles (1.4%). Two screws (one in each of two patients) were positioned inappropriately (0.9%, Grade 3), unilaterally and directly in the vertebral foramen, as shown on postoperative CT scans; blood circulation was normal on angiography. The fusion rate was 100%. The average screw length used for C3 to C7 was 32 mm. The patients were followed up for an average of 35.7 months (range: 17-60 months). There was no morbidity or mortality in our study. We concluded that CPF provides very strong cervical spine fixation but also carries a risk of pedicle perforation without neurovascular injury. However, a free-hand technique performed by an experienced surgeon is acceptable for CPF for various cervical pathologies.