后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响

目的 研究后方韧带复合体逐级切除对损伤胸腰椎稳定性的影响,验证棘上韧带对维持损伤胸腰椎稳定的作用。方法 取8具健康新鲜人体T11~L3节段标本,于L1椎体中1/3行楔形切除,并在材料试验机上压缩至闭合以制备L1椎体骨折。对T12~L1处后方韧带复合体按照关节囊、棘间韧带、棘上韧带、黄韧带的顺序进行逐级切除,依次连续测量T12~L1节段前屈、后伸、侧弯、旋转运动时的运动范围（range of motion, ROM）及中性区（neutral zone, NZ）变化。结果 在前屈和后伸运动中,椎体切除及棘上韧带断裂后,ROM及NZ显著增加。在侧弯运动中,椎体切除和关节囊破坏后,ROM显著增加。在旋转活动中,椎体切除及关节囊破坏导致ROM增加,NZ无显著增加。结论 棘上韧带断裂后,T12~L1节段稳定性发生显著下降,尤其在前屈运动中。棘上韧带是维持胸腰椎节段稳定性的关键韧带。

Effects from sequential removal of posterior ligamentous complex on stability of injured thoracolumbar spine

Objective To investigate the effect from sequential removal of posterior ligamentous complex (PLC) on stability of injured thoracolumbar spine, and verify the role of supraspinous ligaments in maintaining stability of injured thoracolumbar spine complex. Methods Eight fresh human thoracolumbar specimens (T11-L3) were selected, and 1/3 of the L1 vertebral body was resected for "V" shape. The specimens were then mounted on the universal testing machine and subjected flexion and compression to make a fracture in L1. PLC in T12-L1 segment was then resected in a sequential manner from facet capsular ligament (FCL), interspinous ligament (ISL), supraspinous ligament (SSL) to ligamentum flavum (LF). The range of motion (ROM) and neutral zone (NZ) of the T12-L1 segment under flexion, extension, lateral bending and rotation movement were measured at each ligament removal step. Results Under flexion and extension, ROM and NZ presented a significant increase after fracture and removal of SSL. Under right lateral bending, ROM increased sharply after reduction of vertebrae and FCL, while the NZ showed a slight increase. Under left axial rotation, removal of vertebrae and FCL resulted in a significant increase in ROM, while the NZ showed no significant increase. Conclusions After removal of SSL, the stability of the T12-L1 segment decreases sharply, especially under flexion motion, and SSL is the pivotal ligament for PLC to maintain the stability of thoracolumbar spine.