Objective To investigate the biomechanics of subtotal corpectomy with different internal fixations in pigs. Methods Fresh Til - L3 spine specimens were adopted from 6 adult pigs. L1 subtotal corpectomy model was established and three reconstruction operations were performed: ( 1 ) Operation 1: anterior approach with single titanium mesh + screw plate internal fixation; ( 2 ) Operation 2 : posterior approach with 270 decompression of spinal canal + single titanium mesh + pedicle screw internal fixation; (3) Operation 3: posterior approach with 360 decompression of spinal canal + double titanium meshes + pedicle screw internal fixation. Non - invasive loading test was adopted for assessment of the stability of integration condition and fixation condition under three reconstruction methods. Results The range of motions (ROM) of T12 ~ L2 in each direction was significantly reduced in reconstruction with Operation 2 or 3 than intact state (P<0. 05). In extension motion, the ROM in Operation 3 was significantly less than that in Operation 1 (P < 0. 05 ) , whereas in other the other directions, there was no significant difference in ROM among three reconstruction methods ( P > 0. 05 ) . Conclusion All the three reconstruction systems provide rigid stability in subtotal corpectomy, in which the posterior approach with 360 decompression of spinal canal + double titanium meshes + pedicle screw internal fixation provides more convenient stability than anterior surgery.%目的 通过比较正常状态、前路单钛网支撑+钉棒内固定、后路椎管减压、单钛网和双钛网加椎弓根钉内固定术式的稳定性,分析各术式之间的生物力学差异.方法 选用6具成年家猪T11~L3脊柱标本,建立L1椎体次全切除模型,进行3种不同的重建术:术1:经前路单钛网支撑+钉棒内固定术;术2:经后路椎管270°减压+单钛网+椎弓根钉内固定术;术3:经后路椎管360°减压+双钛网+椎弓根钉内固定术.采用非损伤性加载对每个标本的完整状态以及3种重建方式下的固定状态的稳定性进行测试.结果 采用术2、术3重建后,在4.0 Nm载荷下T12~L2各运动方向的运动范围均较完整标本小(P<0.05),在后伸运动中,术3的运动范围小于术1,差异有统计学意义(P<0.05),其他运动中,3种重建方式之间差异无统计学意义(P>0.05).结论 对比正常状态及前路钛网支撑+钉棒内固定术,后路椎管减压+单钛网+椎弓根钉内固定术和后路椎管减压+双钛网+椎弓根钉内固定术均能重建脊柱的即刻稳定性;在后伸运动中,后路双钛网术式的脊柱即刻稳定性优于前路术式.
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