选择性胸椎融合治疗青少年特发性脊柱侧凸的研究进展

The research progress of selective thoracic fusion for adolescent idiopathic scoliosis

中文关键词:  Hangman骨折  C2椎弓根螺钉  “Ω”形横连  三维有限元  生物力学

英文关键词:Hangman fracture  C2 pedicle screws  "Ω" transverse connection  Three-dimensional finite element  Biomechanics

中文摘要:

  青少年特发性脊柱侧凸（adolescent idiopathic scoliosis，AIS）是临床上最常见的脊柱畸形，以脊柱侧凸和旋转畸形为特点，不伴有脊柱本身以及神经肌肉发育等异常，多发生于青少年时期。目前AIS的发病机制尚不明确，AIS不但可以导致躯体冠状位或者矢状位失衡，引发椎体以及躯干的代偿，引起患者顽固性疼痛，严重者还可影响心肺功能并可导致脊髓损害，因此在保守治疗无效时，合理的手术治疗尤为重要。 AIS的手术治疗原则为矫正畸形以及稳定脊柱，由于目前的矫形手术需要牺牲脊柱的运动节段，如何尽可能保留脊柱运动功能，缩短融合节段成为脊柱外科的热点问题之一，此外如何减少融合节段远端邻近节段的退变也逐渐受到了广泛关注。 相比于非选择性融合，选择性胸椎融合（selective thoracic fusion，STF）即对于以胸弯为主弯的AIS患者，仅融合固定胸弯，因其保留脊柱运动功能、减少手术暴露时间、避免远端邻近节段退变等优点逐渐得到了医生们的青睐[3]。STF最早由King等[4]于1983年首次提出，随着内固定系统以及手术技术的不断发展，脊柱外科医生对于STF的研究也逐渐深入。笔者将从STF治疗AIS不同分型下的融合指征、目前值得关注的问题及如何避免术后并发症发生等方面进展进行综述。

英文摘要:

  【Abstract】 Objectives: To investigate the biomechanical characteristics of two different C2 pedicle screws (common and new) combining "Ω" transverse connection for type Ⅱ Hangman fractures. Methods: C0-3 vertebrae of a healthy male adult were scaned by CT, and the original data of CT images were obtained. The finite element model(including intervertebral disc, ligament and other tissues) of normal C0-3 was established by Mimics10.01 et al, and the validity of the model was verified. On the basis of the verified finite element model, the following models were established: Hangman fracture model, Hangman fracture + common C2 pedicle screws + "Ω" transverse model, Hangman fracture + new C2 pedicle screws + "Ω" transverse model. Range of motion(ROM) and implant stress of each model in different working conditions were compared. Results: Under physiological load, the ROM of Hangman fracture model in flexion, extension, lateral flexion and torsion was significantly higher than that of normal cervical spine model, mainly in C2-3, which increased by 3.89°, 5.65° and 2.10°, and the ROM of C2-3 of two internal fixation models was significantly lower than that of fracture model. The ROM between two internal fixation models was similar. The stress of screws in two internal fixation models reached the largest when they extended back, which was 403.3MPa and 370.4MPa respectively, and the stress mainly concentrated in the part of the screws passing through the fracture line. The maximum stress of the new C2 pedicle screws was lower than that of the common C2 pedicle screws in all working conditions. Conclusions: Two different C2 pedicle screws (common and new) combining "Ω" transverse connection can effectively restore the stability of cervical vertebra while retaining the physiological activity of cervical vertebra. The new C2 pedicle screws had better anti-fatigue effect than the common C2 pedicle screws.