胸椎椎弓根髓腔内径CT分型在严重僵硬性脊柱畸形矫形中的临床意义

目的探讨基于胸椎椎弓根髓腔内径CT分型在对严重僵硬性脊柱畸形行经后路全脊椎切除术(posterior vertebral column resection,PVCR)矫形徒手植钉中的临床意义。方法 2004年10月-2010年7月对56例严重僵硬性脊柱畸形患者一期行PVCR矫形,T2～12共植入1 098枚椎弓根螺钉。于CT片测量胸椎椎弓根髓腔内径,并划分为4个区间:区间1(0～1.0 mm),区间2(1.1～2.0 mm),区间3(2.1～3.0 mm),区间4(3.1 mm);对各区间椎弓根螺钉植钉成功率进行统计学分析。根据结果将无统计学意义的区间合并,再次行统计学分析。根据Lenke的椎弓根形态学分型,行各型植钉成功率统计学分析。结果 1 098枚胸椎椎弓根螺钉中,826枚(75.23%)植钉成功。根据髓腔内径分区,除区间3与区间4椎弓根植钉成功率比较差异无统计学意义(χ2=2.540,P=0.111)外,其余各组间比较差异均有统计学意义(P0.008)。区间3、4合并后,区间1、2、3植钉成功率分别为35.05%、65.34%、88.32%,两两比较差异均有统计学意义(P0.017)。根据Lenke的椎弓根形态学分型,A、B、C、D型植钉成功率分别为82.31%、83.40%、80.00%、30.28%,D型植钉成功率显著低于其余各型(P0.008),其余各型间差异均无统计学意义(P0.008)。基于胸椎椎弓根髓腔内径CT分型标准,Ⅰ型椎弓根占总数的17.67%,凹、凸侧椎弓根分别为24.59%、10.75%;Ⅱa型占总数的16.03%,凹、凸侧分别为21.13%、10.93%;Ⅱb型占总数的66.30%,凹、凸侧分别为54.28%、78.32%。各型凹、凸侧分布比较差异均有统计学意义(P0.001)。结论基于胸椎椎弓根髓腔内径提出了量化分型标准,Ⅰ型为无髓腔型,椎弓根内径0～1.0 mm;Ⅱ型为有髓腔型,其中Ⅱa型椎弓根内径为1.1～2.0 mm,Ⅱb型2.1 mm。该分型标准可在行PVCR时指导徒手植入胸椎椎弓根螺钉,但其有效性需进一步临床观察验证。

Clinical significance of thoracic pedicle classification by inner cortical width of pedicles on CT images in posterior vertebral column resection for treatment of rigid and severe spinal deformities

Objective To investigate the clinical significances of the thoracic pedicle classification determined by inner cortical width of pedicle in posterior vertebral column resection(PVCR) with free hand technique for the treatment of rigid and severe spinal deformities.Methods Between October 2004 and July 2010,56 patients with rigid and severe spinal deformities underwent PVCR.A total of 1 098 screws were inserted into thoracic pedicles at T2-12.The inner cortical width of the thoracic pedicle was measured and divided into 4 groups: group 1(0-1.0 mm),group 2(1.1-2.0 mm),group 3(2.1-3.0 mm),and group 4(> 3.1 mm).The success rate of screw-insertion into the thoracic pedicles was analyzed statistically.A new 3 groups was divided according to the statistical results and the success rate of screw-insertion into the thoracic pedicles was analyzed statistically again.And statistical analysis was performed between different types of thoracic pedicles classification for pedicle morphological method by Lenke.Results There were significant differences in the success rate of screw-insertion between the other groups(P < 0.008) except between group 3 and group 4(χ2=2.540,P=0.111).The success rates of screw-insertion were 35.05% in group 1,65.34% in group 2,and 88.32% in group 3,showing significant differences among 3 groups(P < 0.017).According to Lenke classification,the success rates of screw-insertion were 82.31% in type A,83.40% in type B,80.00% in type C,and 30.28% in type D,showing no significant differences(P > 0.008) among types A,B,and C except between type D and other 3 types(P < 0.008).In the present study,regarding the distribution of different types of thoracic pedicles,types I,II a,and II b thoracic pedicles accounted for 17.67%,16.03%,and 66.30% of the total thoracic pedicles,respectively.The type I,II a,and II b thoracic pedicles at the concave side accounted for 24.59%,21.13%,and 54.28%,and at the convex side accounted for 10.75%,10.93%,and 78.32%,respectively.Conclusion A quantification classification standard of thoracic pedicles is presented according to the inner cortical width of the pedicle on CT imaging: type I thoracic pedicle,an absent channel with an inner cortical width of 0-1.0 mm;type II thoracic pedicle,a channel,including type IIa thoracic pedicle with an inner cortical width of 1.1-2.0 mm,and type IIb thoracic pedicle with an inner cortical width more than 2.1 mm.The thoracic pedicle classification method has high prediction accuracy of screw-insertion when PVCR is performed.