下颈椎侧块螺钉固定安全性的解剖学研究

目的　通过解剖学研究 ,确定下颈椎侧块螺钉安全的植入途径。方法　取 2 8具C3～ 7标本 ,解剖确定安全的入、出钉点后摄取C3～ 7各椎体的横断面X线片 ,测量片上C3～ 6横突孔外缘与入钉点连线和矢状轴之间的成角。结果　侧块背面中心内侧 1mm处是安全的入钉点 ,横突与关节突相交处是安全的出钉点。C3～ 6横突孔外缘与入钉点连线和矢状轴成外偏 5～ 12° ,椎体间差异无显著性 (P >0 .0 5 )。结论　颈椎侧块外上象限是螺钉植入的安全区 ,横突与关节突相交处是安全的出钉点。颈椎侧块螺钉置入时保持外倾 15°以上 ,不会损伤椎动脉。     

下颈椎经关节螺钉固定“两点法”置钉的解剖学研究

目的通过解剖学研究,获得下颈椎经关节螺钉的安全置钉方法。方法取18具颈椎标本,仔细解剖颈部的后方和前侧方,以清楚地暴露颈椎侧块,保护好脊神经前、后支（C2～8）及与周围结构的关系。确定安全进、出钉：以侧块背面中心点内侧1mm为进钉点;下位椎体上关节突的侧前方,横突与关节突相交处为出钉点。从C2/C3～C5/C6直视下通过以上2点置入克氏针,通过正侧位X线片测量克氏针在矢状面上的尾倾角、在冠状面上的外倾角及进钉深度,以确定经关节螺钉固定的进钉角度和螺钉长度,并测量经关节螺钉出钉点与脊神经前、后支和椎动脉的距离。结果实验中所有克氏针均成功置入。经关节螺钉的外倾角度为16.5°±5.1°,尾倾角度为36.6°±5.1°,钉道长度为19.0mm±1.2mm。经关节螺钉的外倾角度和尾倾角度在各节段间略有不同,但差异均无统计学意义（P〉0.05）,但钉道长度在C2/C3与C3/C4/C5/C6间差异有统计学意义（P〈0.05）。经关节螺钉出钉点与脊神经前支距离为18.2mm±2.3mm,与后支距离为7.3mm±1.4mm,与椎动脉距离为5.8mm±1.5mm,在各节段间略有不同,但差异均无统计学意义（P〉0.05）。结论使用下颈椎经关节螺钉固定技术时建议以侧块背侧中心点内侧1mm为进钉点,在矢状面上尾倾35°～40°,在冠状面上外倾15°～20°,尽量将螺钉从下位椎体上关节突的侧前方、横突后嵴与关节突连接处出钉。     

侧弓滋养血管孔对枢椎侧方椎弓内固定的影响

目的观察枢椎侧弓上滋养血管孔的分布。方法观察测量58例干燥标本，CT扫描8例新鲜标本，了解滋养血管孔的分布。结果干燥标本左右侧分别有37．93％(22／58)、27．59％(16／58)在横突孔内界外皮质上存在滋养血管孔。新鲜标本4例左侧横突孔内界外皮质上存在滋养血管孔。双侧峡部各有1例滋养血孔穿透峡部内侧或外侧骨皮质进入侧弓内。结论部分枢椎侧弓上存在滋养血管孔造成侧弓先天隆骨皮质缺损，使得依据探测四壁是否完整米判定钉道是否破坏不可靠。     

下颈椎经关节螺钉固定“两点法”置钉的解剖学研究

【摘要】 目的 通过解剖学研究,获得下颈椎经关节螺钉的安全置钉方法。 方法 取18具颈椎标本,仔细解剖颈部的后方和前侧方,以清楚地暴露颈椎侧块,保护好脊神经前、后支（C2~8）及与周围结构的关系。确定安全进、出钉：以侧块背面中心点内侧1 mm为进钉点;下位椎体上关节突的侧前方,横突与关节突相交处为出钉点。从C2/C3~C5/C6直视下通过以上2点置入克氏针,通过正侧位X线片测量克氏针在矢状面上的尾倾角、在冠状面上的外倾角及进钉深度,以确定经关节螺钉固定的进钉角度和螺钉长度,并测量经关节螺钉出钉点与脊神经前、后支和椎动脉的距离。 结果 实验中所有克氏针均成功置入。经关节螺钉的外倾角度为16.5°±5.1°,尾倾角度为36.6°±5.1°,钉道长度为19.0 mm±1.2 mm。经关节螺钉的外倾角度和尾倾角度在各节段间略有不同,但差异均无统计学意义（P＞0.05）,但钉道长度在C2/C3与C3/C4 /C5 /C6 间差异有统计学意义（P＜0.05）。经关节螺钉出钉点与脊神经前支距离为18.2 mm±2.3 mm,与后支距离为7.3 mm±1.4 mm,与椎动脉距离为5.8 mm±1.5 mm,在各节段间略有不同,但差异均无统计学意义（P＞0.05）。 结论 使用下颈椎经关节螺钉固定技术时建议以侧块背侧中心点内侧1 mm为进钉点,在矢状面上尾倾35°~40°,在冠状面上外倾15°~20°,尽量将螺钉从下位椎体上关节突的侧前方、横突后嵴与关节突连接处出钉。     

不同长度的下颈椎经关节螺钉侧位X线片评价

目的评价侧位X线片在了解下颈椎经关节螺钉固定中不同长度螺钉钉尖安全位置的作用。方法选用7具尸体颈椎标本,从C3、4~C5、6直视下依次置入经关节螺钉,分别置入螺钉钉尖仅为四层皮质固定(0mm)和超出皮质2、4、6mm各42枚,分别摄标本侧位X线片。根据X线片,将每个椎体分为前Ⅰ、Ⅰ、Ⅱ、Ⅲ和Ⅳ区。逐一记录螺钉钉尖在X线片上相应椎体各区的位置。结果共有87枚螺钉位于前Ⅰ区,其中42枚是当螺钉钉尖为四层皮质固定时(100%);37枚是当钉尖超出下位椎体上关节突侧前方皮质2mm时(88%);8枚是当钉尖超出4mm时(19%)。共有71枚螺钉位于Ⅰ区,其中5枚是当钉尖超出2mm时(2%);34枚是当钉尖超出4mm时(80%);32枚是当钉尖超出6mm时(76%)。10枚位于Ⅱ区的螺钉均是当钉尖超出6mm时的投影。没有发现螺钉钉尖位于Ⅲ区和Ⅳ区。不同长度的经关节螺钉钉尖在侧位X线片上的投影位置在颈椎各节段间差异无统计学意义(P>0.05)。结论在评价下颈椎经关节螺钉固定中不同长度的螺钉钉尖安全位置方面,侧位X线片有一定意义。下颈椎经关节螺钉理想长度的钉尖位置应该位于前Ⅰ区。     

颈椎椎体间撑开对椎间孔面积影响的实验研究

目的：确定颈椎椎间植骨块撑开高度与椎间孔面积的关系。方法：采用新鲜成人颈椎标本,以椎间盘高度为基础行椎间不同程度对称性撑开。Ｘ线４５°斜位摄片,图像分析计算椎间孔面积。结果：当撑开２～３ｍｍ时,椎间孔面积显著性增大（Ｐ＜０．０５）。结论：颈椎椎间植骨块撑开的理想高度为高出椎间盘２～３ｍｍ。     

斜位X线片对颈椎间孔显示的放射解剖学研究

目的观察颈斜位X线片对椎间孔的显示情况,探讨颈斜位X线片对椎间孔显示的价值。方法在新鲜人体的解剖标本上,用细铅丝标记颈椎间孔的内口和外口,拍摄不同角度的颈椎斜位X线片。结果颈椎间孔外口处铅丝围成的面积比内口面积大;同一颈椎间孔的内、外口处铅丝不重合,且颈椎间孔内口处铅丝的位置比外口处高,C5、C6、C7尤其明显;45°斜位摄影时,C3、C4椎间孔外口显示良好,60°以上时,C6、C7椎间孔外口能显示良好,而C3、C4则显示不理想。结论颈椎斜位X线片对椎间孔显示有一定的局限性。     

Caspar型颈椎撑开器在颈椎间减压手术中的应用研究

目的:探讨使用Caspar型颈椎撑开器在颈前路椎间减压手术中对颈椎椎间角度、椎间孔大小的影响。方法:取10具C2~C7成人颈椎标本,将Caspar型颈椎撑开器的2枚固定螺钉分别在C4、C5椎体正中相互平行置入,按照Smith-Robinson手术方法进行C4/5间隙减压,用颈椎撑开器加压2mm和撑开2mm、4mm,分别在CR机上摄颈椎侧、斜位片,Pacsout程序软件测量C4/5椎间孔面积和椎间角度,SAS6.12软件包进行统计分析。结果:颈椎撑开器压缩2mm,椎间孔面积无明显改变,椎间角度减小39.7%;撑开2mm时,椎间孔面积增加28.3%,椎间角度增加67.6%;撑开4mm时,椎间孔面积增加33.3%,椎间角度增加136.8%。结论:颈椎撑开器撑开椎间隙时扩大了椎间孔面积,同时也增加了椎间角度;提示不应强求使用颈椎撑开器过度撑开椎间隙的方法来增加椎间孔面积。     

虚拟手术系统支持下寰椎侧块螺钉固定相关数据的测量

[目的]通过结合当前虚拟手术系统辅助手术的优势,测量寰椎侧块螺钉固定通道的相关数据.[方法]选取8例16侧无破损和畸形的寰椎(C1)防腐头颈标本,先行CT扫描,后将数据导入虚拟手术系统进行重建,测量寰椎侧块数据:选择侧块与后弓根部下方交界区和横突孔的内侧缘与寰椎后弓内侧壁中点为进钉点,测最,L1:横突孔的内侧缘与寰椎后弓内侧壁的距离,L2:进钉点与侧块前缘最高点的距离,L3:进钉点与侧块前缘的垂直距离,α:进钉点的垂线与寰椎侧块上缘切线的角度,β:进钉点垂线与横突孔内侧缘切线的角度,γ:进钉点垂线与侧块内侧缘切线的角度,内斜角度δ:(β+γ) /2-β.左右两侧均测量3次,取其均值,进行统计学分析.[结果]虚拟手术系统测量寰椎侧块相关参数L1、L2、L3、α、β、γ、δ,经统计学分析,左右侧测量值均无统计学差异(P＞0.05).[结论]选择侧块与后弓根部下方交界区处寰椎后弓内壁外约5 mm为进钉点,侧块螺钉进钉深度在18～22 mm,上倾斜约18°～20°,在矢状位上可内收6°.     

寰椎侧块螺钉钉道与颈内动脉位置关系的三维CT血管成像分析

背景：植入寰椎侧块的双皮质螺钉存在损伤位于寰椎侧块前方的颈内动脉的风险。目的：通过对颈部三维CT血管成像多平面重建测量,研究寰椎侧块螺钉钉道与颈内动脉的位置关系,以避免寰椎侧块螺钉植入造成颈内动脉的损伤。方法：从2012年9月至2012年11月行头颈CT血管造影扫描的患者中选取寰枢椎及头颈部血管无明确病变者126例,利用其图像数据进行三维多平面重建成像,在寰椎侧块螺钉进钉平面上测量颈内动脉与寰椎前皮质的最短距离,寰椎侧块的宽度,颈内动脉内侧缘分别至寰椎正中线、过横突孔内侧缘的矢状线、过进钉点的矢状线的距离,并测量进钉点与颈内动脉内侧缘切线的外偏角,同时在进钉平面上根据寰椎侧块进行区域划分,根据颈内动脉内侧缘所在区域分析颈内动脉与寰椎侧块的位置关系。结果：在寰椎侧块螺钉进钉平面上,颈内动脉与寰椎前皮质的最短距离为（3．32±1．07）mm,有35侧（13．9％）小于2mm,最小值为1．49mm;颈内动脉内侧缘至寰椎正中线的距离为（22．99±2．86）mm;颈内动脉内侧缘与过横突孔内侧缘的矢状线距离为（1．08±1．50）mm,其中182侧（72．2％）颈内动脉内侧缘位于横突孔内侧;颈内动脉内侧缘与过进钉点的矢状线距离为（3．99±1．84）mm;进钉点与颈内动脉内侧缘切线的外偏角为（9．90±5．57）°,最小值为-4．6°,其中有17侧（6．7％）小于0°。各项测量指标左、右侧差异均无统计学意义（P〉0．05）。颈内动脉内侧缘位于侧块外侧有95侧（37．7％）,位于侧块前方有157侧（62．3％）,其中位于侧块前方区域外1／3有136侧（54．O％）,位于侧块前方区域中1／3有21侧（8．3％）,未发现有位于侧块前方内1／3及侧块内侧者。结论：颈内动脉位于寰椎侧块的前外侧方,采用5°的内偏钉道有利于避免寰椎双皮质侧块螺钉对颈内动脉的损伤,术前通过颈部三维CT血管成像可以清楚地显示两者的解剖位置关系,为寰椎侧块螺钉的安全植入提供帮助。     

下颈椎经关节螺钉植入深度的侧位X线片评价

目的 运用侧位x线片评价下颈椎经关节螺钉植入深度的安伞性.方法 采用6具新鲜颈椎标本(C1～T1),每具标本均在直视下植入下颈椎经关节螺钉(每侧4枚螺钉:C3,4、C4,5、C5,6、C6,7各1枚),分别在植入螺钉尖端穿出最后一层皮质0、2、4、6 mm时摄标准侧位x线片,将侧位X线片上椎体垂直等分为四部分,定义为1～4区,并定义椎体后缘之后相当宽度的区域为前1区.每次植入时记录螺钉尖端在X线侧位片的位置,以综合评价螺钉植入的安全性.结果 在C3,4和C4,5螺钉尖端穿出最后一层皮质0 mm时,87.5％在1区,穿出2 mm时,54.2％在1区.当螺钉尖端穿出4 mm时,75.O％在2区,穿出6mm时58.3％在3区.在C5,6和C6,7,穿出0mm时75.0％位于前1区,穿出2mm时,54.2％位于前1区;穿出4 mm时83.3％位于1区,穿出6mm时,50.0％位于2区.结论 侧位X线片町用于评价下颈椎经关节螺钉植入深度的安全性.在侧位X线片上,理想的螺钉尖端位置为C3,4和C4,5应位于1区,而在Cs,6和C6.7应位于前1区.     

双侧斜位X线片判定颈椎椎弓根螺钉置入孔道准确性的实验研究

目的:探讨螺旋形导针配合双侧斜位X线片判断颈椎椎弓根螺钉置入孔道准确性的可行性。方法:在干燥人C3￣C7标本的椎弓根峡部环扎钢丝,拍摄X线片。做出通过椎弓根中央及破坏椎弓根内、外侧壁种孔3道,插入螺旋形导针,拍摄X线片。分别采用前后位与单侧斜位X线片相结合、单侧斜位X线片及双侧斜位X线片判定导针置入位置,比较X线片判定结果与实际所做孔道的符合率。结果:斜位X线片上,椎弓根椭圆形影是由椎弓根峡部形成的,螺旋形导针在判断椎弓根置入孔道位置时,双侧斜位X线片法的敏感性、特异性和准确性高于前后位与单侧斜位片结合法和单侧斜位片法。前后位与单侧斜位X线片相结合、单侧斜位X线片、双侧斜位X线片三种读片方法判定导针置入位置准确性分别为75.78%、88.89%、93.05%,三者之间存在显著性差异(P<0.05)。判断位于椎弓根中央、穿破内侧椎弓根皮质和穿破外侧皮质这3种孔道位置时,双侧斜位X线片法的准确性分别为90.21%、90.76%、94.74%,高于其它两种读片方法(P<0.05)。结论:螺旋形导针配合双侧斜位X线片用于判断颈椎椎弓根螺钉置入孔道位置的准确性是可行的。     

Radiographic evaluation of the position of implants in the medial malleolus in relation to the ankle joint space: anteroposterior compared with mortise radiographs

BACKGROUND: Displaced transverse fractures of the medial malleolus are commonly treated with open reduction and internal fixation with two screws or wires. A mortise radiograph is often used to verify the position of the implants relative to the joint space. However, because the medial and lateral talomalleolar spaces are normally not parallel, the mortise projection (which is colinear with the lateral space) does not provide an accurate radiograph of the medial joint space. METHODS: In ten cadaveric ankles, two wires were inserted into the medial malleolus, as is done for fixation of a fracture, and the distance of the wires from the joint space was measured on an anteroposterior radiograph, on mortise radiographs made with the foot in 15 and 30 degrees of internal rotation, and on anatomical cross section. RESULTS: The measurement on the anteroposterior radiograph exceeded the anatomical measurement in only two specimens, and the discrepancy was 0.5 millimeter in both instances. Measurement of the osseous thickness between the joint surface and the posterior wire on the mortise radiographs always revealed a lower value than the measurements on the anteroposterior radiograph and the anatomical cross section of the same specimen. There was a false appearance of intra-articular placement of the posterior wire on the 15-degree mortise radiographs of four specimens and on the 30-degree mortise radiographs of eight specimens. CONCLUSIONS: These findings demonstrate that the mortise projection provides an oblique radiograph of the medial joint space that can inaccurately reflect the true position of fixation implants in the medial malleolus. Because an anteroposterior radiograph is made with the articular surface of the medial malleolus tangential to the beam, it provides a more accurate representation of implants in the medial malleolus.     

Computed tomography in the determination of transarticular C1-C2 screw length

This study evaluated the significance of computed tomographic (CT) measurements of the upper cervical vertebrae and their clinical implications in transarticular C1-C2 screw placement. In the first part of the study, analysis of axial CT scans of the atlas of 46 patients who had a normal C1-C2 region was performed. Measurements included the vertical distance between the middle of the ventral cortex of the lateral mass and the anterior-most point of the anterior tubercle, and the angle of the anterior ring of C1 relative to the frontal plane. In the second part, axial CT scans of the upper cervical spine were performed in seven cadaveric cervical spines and analyzed using the same criteria. Using the Magerl technique of transarticular C1-C2 screw placement, one screw was placed in each cervical spine. Following each placement, a strict lateral radiograph was taken and the distance between the tip of the screw and the anterior-most point of the anterior tubercle of C1 was measured. Analysis of the cervical cadaveric specimens showed the vertical distance between the middle of the ventral cortex and the anterior-most part of the anterior tubercle when measured on CT scan corresponded to the distance measured on lateral radiographs after placement of the C1-C2 transarticular screw. The study of the 46 patients with normal C1-C2 region had shown the mean values of linear and angular measurements to be greater in males than in females, although no significant difference was found between the two groups (P>.05). The mean distance between the anterior-most point of the anterior tubercle and the middle of the ventral cortex of the lateral mass was 6.5+/-1 mm, and the mean transverse angle of the anterior ring relative to the frontal plane was 22 degrees+/-3.1 degrees. Axial CT evaluation of the individual anatomic relationships of the atlas is simple and may be a useful guide in the determination of the length of the transarticular screw when performed during surgery under lateral fluoroscopic control.     

Usefulness of the nutrient foramen of lamina for insertion of thoracic pedicle screws

STUDY DESIGN: A cadaveric study. OBJECTIVE: To determine the utility of the nutrient foramen on the lamina in thoracic pedicle screw fixation. SUMMARY OF BACKGROUND DATA: Recent studies have examined the portal of entry for pedicle screws. Unfortunately, there is no distinct anatomic marker, and the portal of entry usually depends on the surgeon's preference. METHODS: This study investigated the nutrient artery foramen on the lamina from fourth to eighth thoracic vertebrae after partial laminectomy of 7 cadaveric spines. A 2-mm Steinmann pin was inserted as follows: vertical insertion on the right nutrient foramens and a 10-degree caudal on the left nutrient foramens. Radiographs and computed tomography were obtained and the relationship between the Steinmann pin and pedicle were analyzed. RESULTS: There were 44 nutrient artery foramens (63%, 44/70). Among them, 31 foramens (70%, 31/44) were on the right. On the lateral radiographs, the right pins were inserted parallel within the upper end plate and the left pins were inserted within the vertebral body in T4 and T5. For T6 to T8, the right pins were inserted below the upper end plate and the left pins were inserted below the center of the vertebral body. On the computed tomography axial scan, 17 degrees of medialization for T4 to T7 and 5 degrees for T8 was possible when the size of pedicle screw for human is considered. CONCLUSIONS: The nutrient artery foramen on the lamina of thoracic vertebrae is useful for inserting the thoracic pedicle screw.     

Modified cervical laminoforaminotomy based on anatomic landmarks reduces need for bony removal.

We describe a modified keyhole laminoforaminotomy (LF) using anatomic landmarks on the posterior aspect of the cervical vertebral body to decompress the intervertebral foramen with minimal bone removal. Twenty-four procedures were performed at C3-4, C4-5, and C5-6; 12 at C6-7; and 3 at C7-Tl. Facets and laminae structures were identified based on relative surgical perspectives. Bony resection was limited as follows: 1) inferior limit; inferior border of the superior facet; 2) superior limit, superior border of the superior facet; 3) lateral limit, a vertical line linking the junction of the lamina-facet to the lateral end of the superior limit; and 4) lateral aspect of the dural sac. Fluoroscopy was used to confirm that the intervertebral space was reached. The amount of bony removal was quantified for the superior and inferior laminae and facets. The length of the exposed nerve root was measured. The intervertebral foramen was exposed and the intervertebral disc reached in all specimens. Fluoroscopy showed that the center of the exposure remained at the same height with the intervertebral space. The mean length of the nerve root was 4.6 mm; the mean percentage of bony resection was 21.8%, 7.5%, 11.3%, and 11.5% for the superior and inferior laminae and facets, respectively. Opening the intervertebral foramen posteriorly consistently exposed sufficient nerve root length and allowed access to the intervertebral disc. The technique offers the most direct and safest method of decompressing the intervertebral foramen while minimizing bony resection. This simple surgical procedure may help reduce postoperative morbidity.     

The location of the pedicle and pars interarticularis in the axis

STUDY DESIGN: This is an anatomic and radiologic study on the lateral mass of the C2 vertebra. OBJECTIVES: To define the location of the pedicle and pars interarticularis in the C2 vertebra. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation of the C2 has been addressed in the literature. However, the use of the anatomic terminology of the pedicle or pars interarticularis (isthmus) in C2 is confusing in most of orthopaedic and neurosurgical literature since C2 is considered a transitional vertebra. METHODS: Twenty dry C2 vertebrae were obtained for observation of the external anatomy of the C2 from superior, lateral, and inferior views. Six C2 vertebrae were harvested from cadavers and sectioned in the sagittal, horizontal, and coronal planes to observe the internal structures of the lateral mass using high resolution radiographs. RESULTS: Based on observation, the pedicle of the C2 vertebra is defined as the portion beneath the superior facet and anteromedial to the transverse foramen. The pars interarticularis or isthmus is defined as the narrower portion between the superior and inferior facets. No remarkable difference in bone density and trabecular bone orientation between the pedicle and pars interarticularis was noted. CONCLUSIONS: It is still more appropriate to call this procedure "transpedicular screw fixation" in the C2 to avoid confusion, although this technique requires placing a screw from the posterior aspect of the inferior articular process through the isthmus and pedicle into the vertebral body.     

枢椎棘突螺钉单侧应用联合对侧椎弓根螺钉固定的有限元分析

目的分析枢椎棘突螺钉单侧应用联合对侧椎弓根螺钉固定在寰枢和枕颈固定中的生物力学稳定性。方法构建正常枢椎解剖、椎板薄和椎动脉变异椎弓根细小3种不同解剖状态下的完整上部颈椎有限元模型作为完整模型组,然后分别模拟齿状突骨折进行寰枢固定和寰椎骨折进行枕颈固定。在寰枢固定中,比较单侧枢椎棘突螺钉+对侧椎弓根螺钉+双侧寰椎侧块螺钉固定组(棘突螺钉组)和枢椎双侧椎弓根螺钉+双侧寰椎侧块螺钉固定组(椎弓根螺钉组);在枕颈固定中,比较单侧枢椎棘突螺钉+对侧椎弓根螺钉+枕骨螺钉固定组(棘突螺钉组)和枢椎双侧椎弓根螺钉+枕骨螺钉固定组(椎弓根螺钉组)。枢椎棘突螺钉分别测试水平、斜向、垂直置钉3种不同的固定技术。模拟颈椎运动,测量枕颈的屈伸、侧屈、旋转的关节活动范围(ROM)。结果在寰枢和枕颈固定中,棘突螺钉组和椎弓根螺钉组的C1~C2屈伸、侧屈、旋转ROM均较完整模型组均明显下降。在寰枢固定中棘突螺钉组C0~C2屈伸、侧屈、旋转的ROM大于椎弓根螺钉组;在枕颈固定中,棘突螺钉组C1~C2侧屈的ROM大于椎弓根螺钉组,棘突螺钉组的C0~C2旋转的ROM大于椎弓根螺钉组。枢椎棘突螺钉分别测试水平、斜向、垂直固定间有差异,但不明显。结论在寰枢和枕颈固定中,枢椎双侧椎弓根螺钉固定和枢椎单侧棘突螺钉联合对侧椎弓根螺钉组合式固定方法均具有良好的稳定性。在寰枢固定中,相对于枢椎棘突螺钉组合式固定,枢椎双侧椎弓根螺钉固定具有更好的寰枢稳定性。在枕颈固定中,枢椎双侧椎弓根螺钉固定在侧屈和旋转活动上较枢椎棘突螺钉组合式固定稳定性更好。枢椎三种棘突螺钉置钉技术间的稳定性差异并不明显。     

颈椎椎弓根进钉通道、进钉点与椎体外侧面三维关系定位分析

目的应用数字技术探讨颈椎椎弓根进钉通道、进钉点与椎体边界位置之间的三维关系。方法采用Mimics 10.01软件对6例健康成人头颈部的连续CT扫描图像进行数字化分析,建立颈椎三维数字解剖模型,导入UG Imageware12.0。定位目标对象三维参照平面。将椎体由前至后分成10等份,以此作为定位分析椎弓根进钉通道边界深度比例的依据,由前至后将10等份标志线确定为椎体边界深度的100%～0%,获得C3～C7左右椎弓根进钉通道在椎体90%边界深度时的外偏角、通道长度及内切圆半径大小,确定最佳进钉点与椎弓根中部水平面的垂直距离、与椎弓根在0o外偏角和头尾偏角时投影内边界外侧线对应在椎板表面标志线之间的垂直距离以及与椎板侧块外侧边界的垂直距离。结果 (1)C3～C7椎弓根进钉通道内切圆半径逐渐增大,范围在2.6～3.8mm之间,其中C7最大,C3最小(左侧:2.6mm,2.7mm,2.9mm,3.1mm,3.4mm;右侧:2.5mm,3.0mm,3.1mm,3.1mm,3.8mm)。(2)C3～C7椎弓根进钉通道长度逐渐增大,范围在23.9～28.2mm之间,C7最大,C3最小(左侧:23.9mm,23.9mm,24.5mm,27.9mm,27.8mm;右侧23.4mm,23.8mm,24.5mm,26.7mm,28.2mm)。(3)C3～C7椎弓根进钉通道外偏角度范围在33.2o～37.9o之间(左侧:33.2o,33.2o,35.0o,35.3o,33.5o;右侧33.2o,37.9o,37.0o,36.3o,34.3o)。(4)C3～C7椎弓根进钉通道最佳进钉点到椎弓根中部水平面垂距分别为:左侧:-0.5mm,0.8mm,-0.3mm,-0.4mm,-0.5mm;右侧:-0.1mm,0.5mm,0.1mm,-0.3mm,-0.1mm,其中上方为正值,下方为负值。进钉点位于参考平面上下1mm左右。(5)C3～C7椎弓根进钉通道最佳进钉点到椎弓根外边界垂距分别为:左侧:-5.8mm,-5.3mm,-6.9mm,-5.7mm,-2.7mm;右侧:-5.4mm,-6.3mm,-6.5mm,-5.9mm,-3.0mm,内侧为正值,外侧为负值。其中C3～C6进钉点位于椎弓根外边界线外侧5～7mm之间,C7进钉点位于边界线外侧3mm左右。(6)C3～C7椎弓根进钉通道最佳进钉点到侧块边界垂距分别为:左侧:4.1mm,4.8mm,3.6mm,2.7mm,3.8mm;右侧:4.1mm,3.3mm,3.3mm,3.4mm,3.3mm,内侧为正值,外侧为负值。C3～C7进钉点位于侧块边界线内侧3～5mm之间。结论 C3～C7椎弓根进钉点以侧块边界和椎弓根外边界作为参考线,C3～C6最佳进钉点位置在两参考标志线中线外侧,C7在两参考标志线中线内侧。