限制性和动力性颈椎前路钢板对颈椎矢状位曲度的影响

The effects of constrained and dynamic anterior plates on sagittal cervical alignment

目的:比较限制性(Constrained)和动力性(Dynamic)颈椎前路钢板融合率、对融合节段及全颈椎矢状面曲度影响。方法:回顾分析97例(C组59例;D组38例)颈椎前路钢板内固定术后的影像学资料,Cobb's法测量颈椎侧位X线片上融合节段和C3～C7矢状位曲度、融合节段前柱高度,比较其术后即刻及随访末期参数的变化。连续骨小梁通过融合区、X线动态侧位片显示融合节段棘突顶点间距离无变化判定为融合。结果:平均随访16.9个月,C、D组融合率分别为91.6%、97.3%。C组融合节段前凸角丢失单节段为1.17°(0～2.9°)、双节段为1.83°(0～3.5°),D组单节段2.57°(0.5°～4.9°)、双节段3.59°(1°～6.1°),两组有显著性差别(P<0.001)。C、D两组全颈椎矢状面曲度术后和随访末比较无显著差异。C组融合节段前柱高度丢失单节段为1.39mm(0.4～2.9mm)、双节段2.37mm(0.6～4.7mm);D组单节段高度丢失为1.77mm(0.7～3.1mm)、双节段为3.54mm(0.9～5.5mm),与C组相比无显著性差异(P>0.05)。结论:动力性颈椎前路钢板可获得较高的融合率,与限制性钢板相比,融合节段前凸角丢失和前柱高度丢失虽然较大,但不影响整个颈椎的前凸角度。

Objective： To compare the effects of constrained （C） vs dynamic （D） anterior cervical plates on instrumented level lordosis angle, over cervical contour and fusion rate. Methods：The radiographic data of 97 cases undergoing anterior cervical discectomy and fusion were reviewed retrospectively. Cobb＇s method was used to evaluate the instrumented level lordosis angle, over cervical contour from C3 to C7 and anterior column height of fused levels on lateral X-ray films from immediately postoperatively to final follow-up. Fusion was determined by bridging trabecular bone and the absence of motion on the tip of spinous processes on flexion-extension films. Results： Follow-up time was about 16.9 months averagely. Fusion rate of group C and D was 91.6% and 97.3% respectively. The instrumented level lordosis angle loss of group C for 1 and 2-level were 1.17°（0-2.9°） and 1.83°0-3.5°）. That＇s of group D were 2.570（0.5°-4.9°） and 3.89°（1-6.1°） respectively. There was a significant difference between two groups（P〈0.001 ）. The over cervical contour angle was unchanged in this study. Settling of anterior column height of fused levels of group C were 1.39 mm （0.4-2.9 mm） for 1-level and 2.37 mm （0.6-4.7 mm） for 2-level. That＇s of group D were 1.77 mm （0.7-3.1 mm） and 3.54 mm （0.9-5.5 mm）. There was no significant difference compared with that of group C （P〉0.05）. Conclusions：Dynamic plate showed an increased fusion rate compared with that of constrained plate for 1 and 2-level anterior cervical fusion. The increased settling of plate sliding toward the discs and fusion level lordosis angle loss of dynamic plate group statistically made no difference on the whole cervical sagittal alignment.