退变性腰椎侧凸畸形患者在极外侧腰椎间融合术中相关神经血管的影像学分析

Imaging analysis of the ventral nerve roots and retroperitoneal vessels with respect to the ex-treme lateral interbody fusion in the spine degenerative lumbar scoliosis

目的了解退变性腰椎侧凸畸形患者的腹部大血管和腰丛神经在L1~2、L2~3、L3~4、L4~5腰椎间隙的分布,选择合适的极外侧腰椎间融合术(XLIF)手术入路。方法将60例退变性腰椎侧凸畸形患者分为4组(每组15例):右侧凸Cobb角<20°者为B组、≥20°者为C组;左侧凸Cobb角<20°者为D组、≥20°者为E组。另选择15例无腰椎侧凸的志愿者为对照(A组)。分别进行L1~2、L2~3、L3~4、L4~5腰椎间隙的MRI平扫,观察腹部大血管及神经在各腰椎间隙的分布,测量并计算其与椎体直径的比值,得出相应的安全区域。结果因腹主动脉主要在椎体左前方上行,且在L3~4椎间隙水平逐渐靠近中线,髂总静脉汇合为下腔静脉后行于椎体右侧,因此同一节段左侧手术窗大于右侧(P<0.05)。取左侧95%CI,A、B、C、D、E 5组的安全区域在L1~2节段分别为93.8%、92.3%、93.4%、92.2%、89.8%,在L2~3节段分别为85.2%、82.4%、81.9%、80.4%、79.7%,在L3~4节段分别为77.2%、75.3%、75.9%、74.9%、72.6%,在L4~5节段分别为70.2%、63.3%、61.9%、66.0%、64.3%。结论在进行XLIF手术时,L1~2、L2~3、L3~4、L4~5椎间隙水平的安全区域逐渐减小,目前常用的下腰椎椎体间融合器规格为(8~12)mm×10 mm×4.5 mm,手术窗足够大,XLIF的融合器冠状位置入是安全可行的。由于侧凸畸形患者相应脊柱发生旋转,使手术安全窗口发生轻微偏移;故主弯凸向右的患者手术切口应稍向后偏,向左侧凸侧凸患者手术切口应稍向前偏,这样手术入路相对较安全,可以避免损伤周围血管和神经。

Objective To determine the variable location of the anterior vascular and nerves anatomy in the L1-2, L2-3, L3-4, L4-5 lumbar distribution in the patients with degenerative lumbar seoliosis. To assess the reliability and the safety of the operation of lower lumbar spine at the patients with degenerative lumbar seoliosis interhody fusion through the extreme lateral interbody fusion（XLIF）. Methods The 60 cases of degenerative lumbar scoliosis patients were divided into 4 groups （15 eases each group）. The right convex Cobb angle 〈20° for the B group, ≥20° for the C group; the left convex Cobb angle 〈20° for the D group, ≥20° of E group, another 15 eases with no lumbar seolio- sis volunteers as eontrol group A. Axial MR images were used to measure： the vertebral endplate anterior posterior （AP） diameter, the overlap between the ventral root and the posterior margin of the vertebra, and the overlap be- tween the retroperitonea] large vessels and the anterior edge of the vertebra. Thus obtained the corresponding security zone for XLIF. Results The operation windows from L1-2 to L4-5 gradually decreased and the left ones were bigger than the right ones（P 〈0. 05）. Taking the 95% confidence interval, the left security zone in L1-2 segment of the A, B, C, D, E five groups were 93.8% , 92. 3%, 93.4% , 92. 2% , 89.8% , L2-3 segment were 85.2% , 82.4% , 81.9%, 80.4%, 79. 7%, L3-4 segment were 77. 2%, 75.3%, 75.9%, 74. 9%, 72. 6%, L4-5 segment were 70. 2%, 63.3%, 61.9%, 66. 0%, 64. 3%. Conclusions The XLIF of L1-5 at the patients with degenerative lumbar scoliosis is safe,reliable and practical. Lumbar vertebral fusion between under the present commonly use specifi- cations for （8 -12）mm × 10 mm × 4. 5 mm, operation window is large enough, XLIF fusion coronary position is safe and feasible. Because the variable location of the neurovascular structures is mostly dependent on the degree of ro- tatory deformity, the safe corridor for performing the discectomy and fusion should be a little backward in the dex- troscoliotic spines, and be slightly forward in the levoscoliotic spines. So it is recommended to take preoperative MRI to assess the relative position of the adjacent neurovascular structures in relation to the lower vertebra＇s endplate at each level.