基于CT测量的腰椎间融合器长度选择分析

Analysis of lumbar interbody cage′s length based on anatomic measurement

目的：通过CT测量分析国人腰骶椎L1-S1终板各径线及相应骨突环等解剖学参数，探讨后方入路腰椎融合手术椎间融合器长度的选择。方法：招募24名健康成年志愿者，男12名，女12名，行腰椎CT扫描及矢状面、终板面二维重建。于L1～S1各终板面测量终板中线斜径、最大斜径、最大倾斜角、侧矢状径及相应径线所覆盖前后骨突环长度，计算均值及标准差。比较同性别同节段上下终板中线斜径、最大斜径、最大倾斜角及侧矢状径，计算不同手术方式下的融合器长度。结果：中线斜径男性最大值为39．58±2．60mm，最小值为33．38±3．26mm；女性最大值为34．89±1．55mm，最小值为30．93±2．99mm；前后覆盖骨突环长度为6，8mm。最大斜径男性最大值为48．05±4．62mm，最小值为42．83±2．28mm；女性最大值为43．26±3．31mm，最小值为38．00±2．53mm；自L1至S1逐渐变大。侧矢状径男性最大值为36．48±3．26mm，最小值为32．11±2．50mm；女性最大值为31．75±1．64mm，最小值为28．36±2．32mm；前后覆盖骨突环长度为5．5。7．5mm。L2～L5较LI／2、L5／S1同节段上下终板对应参数均保持较好一致性，差异多无统计学意义。LJ5／S1节段上下终板四对参数中只有最大斜径差异无统计学意义（男性，P=0．0522；女性，P=0．6410）。根据拟定融合器计算公式，TLIF融合器长度男性L1～14各节段应≥31mm，L4／5为30～38mm，L5／S1为25—38mm；女性L1-L4各节段应≥27mm，L4／5为26～34mm，L5／S1为23～33mm。TLIF入路下融合器置入角度应尽量达到最大倾斜角以选用更长融合器。PLIF融合器长度男性L1。L5各节段为28～30mm，L5／S1为26mm；女性L1～IJ5各节段为24—26mm，L5／SI为22mm。结论：CT测量分析可为腰椎间融合器长度的选择提供客观依据，根据终板斜径、侧矢状径及骨突环长度可初步预测手术节段椎间融合器长度。

Objectives： To measure the anatomic parameters of Chinese lumbosacral vertebral endplates（L1- S1）, and to explore its significance in the selection of interbody eage＇s length used in transforaminal lumbar interbody fusion（TLIF） and posterior lumbar interbody fusion（PLIF）. Methods： CT scan and reconstructions of lumbar and sacrum were obtained in 24 healthy adult volunteers. Mid-oblique diameter, max-oblique diameter, max-oblique angle, lat-sagittal diameter and width of apophyseal ring of L1 inferior endplate to S1 superior endplate were measured. Within the same gender and segment, mid-oblique diameter, max-oblique diameter, max-oblique angle and lat-sagittal diameter of the inferior and superior endplates were compared, and the length of the fusion under the different operation methods was calculated. Results： The maximum and minimum mid-oblique diameters were 39.58±2.60mm and 33.3g±3.26mm in male, which were 34.89± 1.55mm and 30.93±2.99mm in female, the width of apophyseal ring for which was within the range of 6- 8mm. The maximum and minimum max-oblique diameters were 48.05±4.62mm and 42.83±2.28mm in male, which were 43.26±.31mm and 38.00±2.53mm in female, which increased from L1 to S1. The maximum and minimum lat-sagittal diameters were 36.48±3.26mm and 32.11±0.50mm in male, which were 31.75±0.64mmand 28.36±0.32mm in female, the width of apophyseal ring for which was within the range of 5.5-7.5mm. Most of the differences between anatomic parameters of inferior and superior endplates in the same segment （L2-L5） was insignificant except for L1/2 and L5/S1. In L5/S1, there was no significant difference only in lat-oblique diameter（male： P=0.0522, female： P=0.6410）. When TLIF was used, the lenght of interbody cage for L1-L4 should be no less than 3hnm in male and 27mm in female. As for L4/5, it should be within the range of 30-38mm in male and 26-34mm in female. The range of length was more extensive for L5/S1, with 25-38mm in male and 23-33mm in female. When the cage was inserted, the insertion angle should be closed to max-oblique angle. When PLIF was used, the length of interbody cage for L1-L5 ranged from 28 to 30mm in male and 24 to 26mm in female. As for L5/S1, 26mm in male and 22mm in female were good choices. Conclusions＇ CT measurement provides the choice of lumbar interbody cage＇s length with objective evidences. A preliminary estimation of the length can be made based on the oblique diameter, the lat-sagittal diameter and the width of apophyseal ring.