前路经寰枢关节螺钉内固定术的解剖学测量及其临床意义

[目的] 为国人前路经寰枢关节螺钉内固定术提供解剖学依据.[方法] 在50套中国成人配套干燥寰枢椎标本上,对前路经寰枢关节螺钉内固定术的相关解剖学数据进行测量.[结果]前路经寰枢关节螺钉内固定术以枢椎前弓下缘与枢椎椎体侧缘交界点上方4mm处为进钉点,在矢状面上螺钉植入的最小外偏角为(10.80±2.10)°,最大外偏角为(25.13 ±3.12)°,冠状面上最小后偏角为(8.85±2.12)°,最大后偏角为(26.96 3.09)°,枢椎正中至枢椎横突孔内侧缘距离为(14.12±1.28)mm,内、外侧钉道长度分别为(17.48±2.10)mm和(25.41±2.59)mm.[结论] 前路经寰枢关节螺钉内固定术中,两侧置入螺钉的理想的钉道角度为外偏10°-25°,后倾9°-27°、理想的螺钉长度为17～25 mm,由枢椎前缘正中向外分离显露不宜超过14 mm.     

后路经寰枕关节螺钉固定钉道的测定

目的:明确后路寰枕关节经关节螺钉固定的技术参数;探讨枕颈部经关节螺钉内固定技术的临床意义。方法:30例含完整寰枕关节干燥骨性标本,直视下行后路寰枕关节经关节克氏针植入后行X线摄片,在X线片上测量寰枕关节经关节螺钉固定的钉道角度和长度。结果:寰枕关节经关节螺钉固定的钉道理想角度为:螺钉方向在矢状面的上倾角为(53.3±3.4)°,在冠状面的内倾角为(20.0±2.6)°。钉道长度为(29.28±2.46)mm。结论:寰枕关节后路经关节螺钉植入存在一定的方向性和钉道长度,结合后路C1-C2经关节螺钉内固定后可视为能满足当前临床需要的一种相对理想的枕颈融合内固定术式。     

前路经寰枢关节螺钉内固定术置钉安全性的CT测量研究

[目的]探讨前路经寰枢关节螺钉内固定术螺钉置入的相对安全范围,为国人行此手术提供CT解剖学依据。[方法]采用多层螺旋CT(MSCT)对20套中国成人常规福尔马林浸泡的寰枢椎标本及30例健康中国成年自愿者的寰枢椎行2.0 mm层厚扫描,1.0 mm层厚重建,在容积重建(VR)及多平面重建(MPR)图像上全方位观察并利用GE RA600 PACS工作站AW三维测量软件进行相关解剖学数据测量,最后对所得结果进行统计学分析,评价置钉安全性。[结果]前路经寰枢关节螺钉内固定术以枢椎前弓下缘与枢椎椎体侧缘交界点上方4 mm处为进针点,在相对于矢状面上螺钉置入的外偏角的参考值范围为17.69°～21.13°,相对于冠状面上螺钉置入的后倾角的参考值范围为11.75°～19.50°,内侧钉道长度的参考值范围为11.19～27.51mm,外侧钉道长度的参考值范围为15.61～31.84mm。[结论]前路经寰枢关节螺钉内固定术是安全可行的,螺钉置入时的理想钉道角度为外偏18°～21°,后倾12°～20°,螺钉长度为16～28 mm。     

前路经枕寰枢关节螺钉内固定术的可行性及安全性研究

目的 通过影像学方法探讨前路经枕寰枢关节螺钉内固定术的可行性和安全性. 方法 随机选取30例健康成人头颈部CT血管造影检查资料,男18例,女12例;年龄21～55岁,平均33.6岁.利用Vitreal 4.0软件测量理想钉道角度、长度及其与椎动脉的距离.在此基础上,对2具防腐枕颈部标本进行模拟手术,行X线及CT检查以明确螺钉位置. 结果 从入钉点平面至锚定点平面椎动脉在形态上有5个恒定的生理弯曲;入钉点平面处两侧椎动脉间距为(25.59±1.04) mm;螺钉内固定理想钉道角度:冠状面上外倾角为18.62°±2.17°,矢状面上后倾角为24.35°±3.02°;理想钉道长度为(35.95±2.16) mm.理想钉道与椎动脉的关系于寰椎横突孔上方稚动脉弯曲平面最为密切,其距离为(3.66±0.55)mm.模拟手术的影像学检查证实钉道角度、长度均位于参考值范围内,无穿出骨质及进入舌下神经管者. 结论 国人采用前路经枕寰枢关节螺钉内固定在解剖上是可行的,钉道与椎动脉之间有一定的安全距离,但术中必须严格控制钉道方向.     

前路经寰枢关节锁定钛板螺钉内固定系统三维稳定性的实验研究

[目的]评价前路经寰枢关节锁定钛板螺钉内固定系统治疗寰枢椎不稳的三维稳定性。[方法]8例颈椎新鲜标本,对每一标本分别测定完整状态、齿状突Ⅱ型骨折、前路经寰枢关节锁定钛板螺钉内固定和后路椎弓根螺钉内固定的三维运动范围,并对结果进行统计学分析。[结果]前路固定的前屈为(1.39±0.26)°,后伸为(1.40±0.22)°,侧屈为(1.43±0.23)°,旋转为(1.77±0.34)°。后路固定的前屈为(1.37±0.23)°,后伸为(1.39±0.20)°,侧屈为(1.41±0.22)°,旋转为(1.77±0.33)°,前路经寰枢关节锁定钛板螺钉固定和后路椎弓根螺钉固定的寰枢椎三维运动范围无显著统计学差异(前屈P=0.930,后伸P=0.952,左右侧屈P=0.947,左右旋转P=0.950)。[结论]前路经寰枢关节锁定钛板螺钉固定术的三维稳定性与后路椎弓根螺钉固定术相当,为寰枢椎不稳患者提供了一种手术治疗选择。     

寰枢椎后路经关节螺钉内固定钉道与椎动脉的解剖学关系研究

[目的]探讨寰枢椎后路经关节螺钉内固定术钉道的安全性.[方法](1)在30套国人干燥寰枢椎标本上测量相关的解剖参数;(2)在6具国人尸体标本上行寰枢椎后路经关节螺钉内固定术,术后行X线及CT检查,观察椎动脉与钉道的解剖学关系.[结果]干燥标本上枢椎上关节面下椎动脉沟深(5.86±1.45)mm;15侧椎动脉沟延伸到枢椎上关节面下内侧1/3,达中1/3和外1/3者分别为36、9侧,其理想钉道内倾角分别为(26.4±3.44)°、(16.1±2.44)°和(15.1±2.24)°.CT图像上测得钉道与椎动脉最小距离位于枢椎椎动脉沟顶点2.75～5.78 mm.[结论]枢椎椎动脉沟的位置决定钉道的角度,在枢椎上关节面下钉道与椎动脉关系最为密切,但两者之间仍有一定的安全范围.     

前路经寰枢关节螺钉内固定术治疗寰枢关节不稳定的解剖学及临床研究

目的 为前路经寰枢关节螺钉内固定术提供临床解剖学依据.方法 在100对中国成人干燥寰、枢椎配对标本上,对与临床前路经寰枢关节螺钉内固定术相关的数据进行解剖学测量.并对11例创伤性寰枢椎不稳定患者施行了前路经寰枢关节螺钉内固定术,在齿状突与寰椎前结节后方置入颗粒状松质骨.结果 前路经寰枢关节螺钉内固定术冠状面上螺钉植入最小外偏角(5.5±2.0)度,最大外偏角(23.6±2.1)度,矢状面上螺钉植入最小后倾角(14.9±2.6)度,最大后倾角(25.6 ±2.5)度,内侧钉道距离(16.58±1.49)mm,外侧钉道距离(26.44±1.75)mln.11例患者中,1例颈脊髓完全损伤患者,术后1个月死于肺部感染.其余10例病例获得随访,时间7个月～3年,平均17个月,无椎动脉及脊髓损伤,所有病例获得骨性融合.结论 前路经寰枢关节螺钉内固定术,操作简便,损伤脊髓或椎动脉的风险较小,为寰枢椎不稳定患者提供了一种新的内固定治疗方法.     

枕寰枢后路经关节螺钉内固定的可行性研究

目的明确后路寰枕关节经关节螺钉固定的螺钉、进钉点植入角度、钉道角度和螺钉长度。探讨枕颈部经关节螺钉内固定技术的手术指征效果和并发症。方法在 2 0例含有完整寰枕关节的干燥骨性标本上 ,直视下进行后路寰枕关节经关节克氏针植入 ,在头尾侧和侧位X线片上测量理想的钉道角度和钉道长度。 30例正常成年人的寰枕关节进行三维CT重建 ,同时测量后路寰椎关节经关节螺钉钉道角度的可调范围。 12例新鲜枕颈部标本进行后路枕颈部关节螺钉内固定 ,术后行正、侧位X线片和三维CT重建 ,以验证螺钉位置。结果干燥标本模拟X线片测量 ,寰枕关节螺钉的钉道在矢状面上呈上倾 ,在冠状面上呈内倾 ,钉道的理想角度为 :在矢状面上倾角为 5 3.3°± 3.4° ,在冠状面内倾角为 2 0 .0°± 2 .6°。螺钉钉道长度为 (2 9.2 8± 2 .4 6 )mm。依据三维CT重建后测量 ,钉道方向与矢状面上倾角存在一个可调范围 ,一般为 4 9.6°± 2 .0°,与冠状面的内倾角也存在一个可调范围 ,一般为 4 0 .4°± 3.4°。齿突与枕髁前方最高点间距为 9.80～ 17.7mm ,平均 (13.4 3± 1.93)mm。寰枕关节关节螺钉内固定 ,影像学检查显示 ,螺钉钉道均经过寰枕关节 ,未进入神经管。结论寰枕关节后路经关节螺钉植入存在一定的方向性 ,钉道长度和钉道角度     

后路经寰枕关节螺钉内固定的解剖学研究

目的明确后路经寰枕关节螺钉固定的技术参数,为临床治疗提供参考。方法20具包含完整寰枕关节的干燥骨标本,于直视下经寰枕关节置入克氏针固定后拍摄X线片,在X线片上测量经寰枕关节螺钉固定的螺钉角度和长度。对30名健康成年人的寰枕关节行三维CT重建,测量后路经寰枕关节螺钉内固定螺钉角度的可调范围。对12具新鲜枕颈部标本行后路枕寰枢经关节螺钉内固定,然后拍摄X线片并行三维CT重建,以明确螺钉位置。结果经寰枕关节固定螺钉方向在矢状面呈上倾,冠状面呈内倾,左右两侧略有不同,但差异无统计学意义(P>0.05)。后路经寰枕关节螺钉固定的理想角度在矢状面的上倾角为53.3°±3.4°,在冠状面的内倾角为20.0°±2.6°,钉道长度为(29.28±2.46)mm。三维CT重建显示上倾角的可调范围为24.9°～74.6°,内倾角的可调范围为0.7°～40.5°。在新鲜标本上按照上述角度进行后路枕寰枢经关节螺钉内固定,影像学检查结果显示,螺钉钉道均经过寰枕关节,无进入神经管者。结论后路经寰枕关节螺钉固定时对准确性要求较高,结合后路C1,2经关节螺钉固定可视为能满足当前临床需要的一种较好的枕颈融合方法。     

寰枕关节后路经关节螺钉固定钉道参数的测定

目的 明确后路寰枕关节经关节螺钉固定的技术参数;探讨枕颈部经关节螺钉内固定技术的临床意义。方法 30例含完整寰枕关节干燥骨性标本,直视下行后路寰枕关节经关节克氏针植入后行X线摄片,在X线胶片上测量寰枕关节经关节螺钉固定的钉道角度和钉道长度。结果 寰枕关节经关节螺钉固定的钉道理想角度为:螺钉方向在矢状面的上倾角为 53. 3°±3. 4°,在冠状面的内倾角为 20. 0°±2. 6°。钉道长度为: (29. 28±2. 46)mm。结论 寰枕关节后路经关节螺钉植入存在一定的方向性和钉道长度问题,结合后路C1, 2经关节螺钉内固定后可视为能满足当前临床需要的一种相对理想的枕颈融合内固定术式。     

Evaluation of biomechanical properties of anterior atlantoaxial transarticular locking plate system using three-dimensional finite element analysis

Purpose

To evaluate a new anterior atlantoaxial transarticular locking plate system using finite element analysis.

Methods

Thin-section spiral computed tomography was performed from occiput to C₂ region. A finite element model of an unstable atlantoaxial joint, treated with an anterior atlantoaxial transarticular locking plate system, was compared with the simple anterior atlantoaxial transarticular screw system. Flexion, extension, lateral bending, and axial rotation were imposed on the model. Displacement of the atlantoaxial transarticular screw and stress at the screw–bone interface were observed for the two internal fixation systems.

Results

Screw displacement was less using the anterior atlantoaxial transarticular locking plate system compared to simple anterior atlantoaxial transarticular screw fixation under various conditions, and stability increased especially during flexion and extension.

Conclusions

The anterior atlantoaxial transarticular locking plate system not only provided stronger fixation, but also decreased screw-bearing stress and screw–bone interface stress compared to simple anterior atlantoaxial transarticular screw fixation.     

Anatomic study of the axis for surgical planning of transarticular screw fixation

Transarticular screw fixation has shown increased stability compared with other posterior stabilization techniques. However, there have been few reports on vertebral artery injury related to the screw insertion. The current study measured the parameters of the pedicle and vertebral artery groove of the axis and clarified the accuracy and safety of the transarticular screw fixation. Direct measurements were taken from 98 dry axis vertebrae. The width and height of the pedicle were measured. The mediolateral and anteroposterior dimensions of the vertebral artery groove also were measured. Forty-one percent had asymmetry. In 20% of the specimens, the pedicle was smaller than the diameter of the screw (3.5 mm). The pedicle of the axis has large anatomic variability and asymmetry. Some pedicles were not suitable for atlantoaxial transarticular screw fixation. The risks associated with screw fixation should be prevented by preoperative computed tomography with three-dimensional reconstruction. Screw trajectory reconstruction with coronal and sagittal reconstruction is useful to evaluate the pedicle width and height.     

枕颈部后路不同内固定的生物力学比较

目的评价不同内固定重建枕颈部稳定性的生物力学性能。方法12具新鲜人体枕颈部标本,在标本完整、枕寰枢不稳、枕颈部植骨块钛缆固定(A组)、枕颈部经关节螺钉内固定(B组)、SUM-MIT枕颈部内固定系统固定(C组)五种状态下,依次用脊柱三维运动测量系统测试其OcC1、C1,2节段的运动参数。同时对固定后的OcC1经关节螺钉(OcC1TA组)、C1,2经关节螺钉(C1,2TA组)、枢椎椎弓螺钉(C2IS组)和枕骨螺钉(Oc Screw组)在生理载荷下三维六自由度运动时,运用电测法测定四种螺钉的拔出应力,并行统计学分析。结果在OcC1节段,B组在屈伸运动中的运动范围和中性区显著大于C组。在侧屈和旋转运动中,A组的运动范围和中性区均明显大于B、C组。在C1,2节段,B组各方向运动的运动范围和中性区均明显小于A组。B组在旋转运动中的运动范围和中性区均显著小于C组。电测法结果显示,侧屈状态下所有螺钉局部应变均接近0;前屈和旋转时螺钉承受不同程度的拉应力,后伸时螺钉承受压应力。Oc Screw组在屈伸和旋转运动状态下,所承受的任何载荷应力均大于其他三种置钉方法。结论枕颈部后路经关节螺钉内固定和SUMMIT枕颈内固定在控制旋转和侧屈的稳定性上有优点。枕骨螺钉承受的拉应力最大,生理环境下枕骨螺钉可能更易发生松动和断裂。     

Biomechanical comparison of occipitoatlantal screw fixation techniques

OBJECT: The stability provided by 3 occipitoatlantal fixation techniques (occiput [Oc]-C1 transarticular screws, occipital keel screws rigidly interconnected with C-1 lateral mass screws, and suboccipital/sublaminar wired contoured rod) were compared. METHODS: Seven human cadaveric specimens received transarticular screws and 7 received occipital keel-C1 lateral mass screws. All specimens later underwent contoured rod fixation. All conditions were studied with and without placement of a structural graft wired between the skull base and C-1 lamina. Specimens were loaded quasistatically using pure moments to induce flexion, extension, lateral bending, and axial rotation while recording segmental motion optoelectronically. Flexibility was measured immediately postoperatively and after 10,000 cycles of fatigue. RESULTS: Application of Oc-C1 transarticular screws, with a wired graft, reduced the mean range of motion (ROM) to 3% of normal. Occipital keel-C1 lateral mass screws (also with graft) offered less stability than transarticular screws during extension and lateral bending (p < 0.02), reducing ROM to 17% of normal. The wired contoured rod reduced motion to 31% of normal, providing significantly less stability than either screw fixation technique. Fatigue increased motion in constructs fitted with transarticular screws, keel screws/lateral mass screw constructs, and contoured wired rods, by means of 19, 5, and 26%, respectively. In all constructs, adding a structural graft significantly improved stability, but the extent depended on the loading direction. CONCLUSIONS: Assuming the presence of mild C1-2 instability, Oc-C1 transarticular screws and occipital keel-C1 lateral mass screws are approximately equivalent in performance for occipitoatlantal stabilization in promoting fusion. A posteriorly wired contoured rod is less likely to provide a good fusion environment because of less stabilizing potential and a greater likelihood of loosening with fatigue.     

Anterior retropharyngeal fixation C1-2 for stabilization of atlantoaxial instabilities: study of feasibility, technical description and preliminary results

Posterior transarticular screw fixation C1-2 with the Magerl technique is a challenging procedure for stabilization of atlantoaxial instabilities. Although its high primary stability favoured it to sublaminar wire-based techniques, the close merging of the vertebral artery (VA) and its violation during screw passage inside the axis emphasizes its potential risk. Also, posterior approach to the upper cervical spine produces extensive, as well as traumatic soft-tissue stripping. In comparison, anterior transarticular screw fixation C1-2 is an atraumatic technique, but has been neglected in the literature, even though promising results are published and lectured to date. In 2004, anterior screw fixation C1-2 was introduced in our department for the treatment of atlantoaxial instabilities. As it showed convincing results, its general anatomic feasibility was worked up. The distance between mid-sagittal line of C2 and medial border of the VA groove resembles the most important anatomic landmark in anterior transarticular screw fixation C1-2. Therefore, CT based measurements on 42 healthy specimens without pathology of the cervical spine were performed. Our data are compiled in an extended collection of anatomic landmarks relevant for anterior transarticular screw fixation C1-2. Based on anatomic findings, the technique and its feasibility in daily clinical work is depicted and discussed on our preliminary results in seven patients.     

前路经寰枢关节螺钉内固定术治疗寰枢椎不稳定的生物力学及临床研究

目的 探讨前路经寰枢关节螺钉内固定术的生物力学稳定性及疗效.方法 8具新鲜颈椎标本,对每一标本先后行正常状态、齿状突Ⅱ型骨折、前路经寰枢关节螺钉内固定术、后路Magerl螺钉内固定术4种状态三维运动范围的测定.并对20例创伤性寰枢椎不稳定患者施行前路经寰枢关节螺钉内固定术,在齿状突与寰椎前结节后方置入颗粒状松质骨.结果 前路经寰枢关节螺钉内固定术与后路Magerl螺钉内固定术均明显减少寰枢关节各方向运动范围,经统计学检验差异无统计学意义.20例患者中,1例颈脊髓完全损伤患者,术后1个月死于肺部感染.其余19例病例获得随访,时间7个月～3年,平均18个月,无椎动脉及脊髓损伤,所有病例获得骨性融合.结论 前路经寰枢关节螺钉内固定术,操作简便,固定可靠,损伤脊髓或椎动脉的风险较小.     

寰枢椎后路经关节螺钉内固定治疗寰枢椎不稳定的生物力学及临床研究

目的评价寰枢椎后路经关节螺钉内固定术两种不同钉道的生物力学稳定性及疗效。方法在8例新鲜尸体标本依次轮流测试正常、Ⅱ型齿状突骨折行AO进钉点与改良进钉点两种后路钉道螺钉固定术模型三维运动范围，并在16例寰枢椎不稳定患者，采用枢椎下关节突下缘正中点为进钉点的方法行经关节螺钉固定及自体颗粒样松质骨植骨术。结果两种入钉方法均能明显减少寰枢关节的各向运动角度（P〈0．01），但两者间差异无统计学意义（P〉0．05）。经5～48个月随访，16例患者寰枢关节稳定性均获得恢复与骨融合，无并发症。结论新入钉点解剖标志明确。钉道长，能提供牢固地固定，并发症发生率低。     

下颈椎经关节螺钉钢板固定的生物力学研究

目的:研究下颈椎单独经关节螺钉固定与经关节螺钉钢板固定的三维稳定性之间的差异。方法:12具新鲜人体颈椎标本,制成C4,5、C5,6节段三柱损伤模型。随机选取6具标本在C4,5、C5,6行单独经关节螺钉固定,另6具标本在C4,5、C5,6行经关节螺钉钢板固定。在非限制性和非破坏性的试验条件下测试它们在前屈、后伸、左右侧弯和轴向旋转运动状态的稳定性,分别测试标本损伤模型制作前完整标本组(A组)、单独经关节螺钉固定组(B组)和螺钉钢板组(C组)3组数据。结果:单独经关节螺钉固定组和经关节螺钉钢板固定组在各方向的运动范围(ROM)和中性区(NZ)的均数均小于完整标本组,差异有统计学意义(P0.05)。经关节螺钉钢板固定在前屈运动中的ROM和NZ与单独经关节螺钉固定比较,差异无统计学意义(P0.05);在后伸、左右侧弯和轴向旋转运动中,经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,差异有统计学意义(P0.05)。结论:下颈椎经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,在使用下颈椎经关节螺钉时,相对于单独螺钉固定,建议以螺钉钢板形式固定。     

Atlantoaxial fusion using anterior transarticular screw fixation of C1–C2: technical innovation and biomechanical study

This study is an attempt to describe a new technique for anterior transarticular screw fixation of the atlantoaxial joints, and to compare the stability of this construct to posterior transarticular screw fixation with and without laminar cerclage wiring. Nine human cadaveric specimens were included in this study. The C1–C2 motion segment was instrumented using either anterior transarticular screws (group 1), posterior transarticular screws alone (group 2), or posterior screws with interlaminar cerclage wires (group 3). Using an unconstrained mechanical testing machine, the specimens were tested in rotation, lateral bending, and flexion-extension using nondestructive loads of ±2 N m. The specimens were also tested in translation using nondestructive loads of ±100 N. All values for the three groups with regards to anterior-posterior displacement, rotation, and lateral bending were similar as determined using a Kruskal–Wallis rank sum test with a significance level of p<0.05. The only significant difference was registered in flexion-extension where the cerclage wire added some strength to the construct. Anterior transarticular screw fixation of the atlantoaxial spine has several advantages over posterior fixation techniques, and is as stable as posterior transarticular fixation in all clinically significant planes of motion. The addition of posterior interlaminar cerclage wiring further improves resistance to flexion-extension forces. Anterior transarticular screw fixation of the atlantoaxial joint is a useful technique for achieving C1–C2 stabilization.