Jain Sudeep, Modi Hitesh N, Suh Seung-Woo, Yang Jae-Hyuk, Hong Jae-Young
Department of Orthopedics, Korea University Guro Hospital, Scoliosis Research Institute, Seoul, South Korea.
J Pediatr Orthop B. 2009 Nov;18(6):369-74. doi: 10.1097/BPB.0b013e32832f59b0.
The aim of this retrospective study was to explain a previously undescribed mechanism of 'pedicle migration or shift' with longitudinal growth of the spine owing to biological remodeling of plastic posterior fusion mass as well as pedicles which may explain at least a few cases of deformity recurrence after posterior fusion in scoliosis surgery. Progressive loss of deformity correction after scoliosis surgery in growing children has been variously described. The various mechanisms described have been 'crankshaft effect', pseudoarthrosis, implant failure (loosening/breakage), biological plasticity, choosing wrong levels, excessive apical translation causing decompensation by unfused segments, progressive etiology, inadequate anchorage provided by some older instrumentation systems, etc. Though there have been claims that segmental pedicle instrumentation might prevent crankshaft phenomenon by providing a more rigid fixation, numerous studies have shown progressive loss of correction even after segmental pedicle instrumentation. A 10.6-year-old girl was fused posteriorly before her prepubertal growth spurt using segmental screw rod instrumentation. The index case in our study showed progressive loss of operative correction during subsequent follow-up at 2 years. This probably occurred because of longitudinal growth of the spine and posterior fusion mass because of its biological plasticity during the period of rapid growth spurt. In conclusion, despite the recent trend towards the use of segmental pedicle instrumented correction and fusion and claims that by providing rigid, tri-column fixation, it enhances fusion and controls growth of the vertebral body anteriorly; caution must be taken in children with high remaining growth and high growth velocity.
这项回顾性研究的目的是解释一种先前未被描述的“椎弓根迁移或移位”机制，该机制与脊柱的纵向生长有关，是由于可塑性后路融合块以及椎弓根的生物重塑所致，这可能解释了脊柱侧弯手术后路融合后至少一些畸形复发的病例。生长中的儿童脊柱侧弯手术后畸形矫正的逐渐丧失已有多种描述。所描述的各种机制包括“曲轴效应”、假关节形成、植入物失效（松动/断裂）、生物可塑性、选择错误的节段、过度的顶椎移位导致未融合节段失代偿、进展性病因、一些较旧的器械系统提供的锚固不足等。尽管有人声称节段性椎弓根器械固定通过提供更坚固的固定可能预防曲轴现象，但大量研究表明，即使采用节段性椎弓根器械固定后仍会出现矫正的逐渐丧失。一名10.6岁女孩在青春期前生长突增前接受了后路融合，采用节段性螺钉棒器械固定。我们研究中的索引病例在随后2年的随访中显示手术矫正逐渐丧失。这可能是由于脊柱和后路融合块在快速生长突增期因其生物可塑性而发生纵向生长所致。总之，尽管最近有使用节段性椎弓根器械矫正和融合的趋势，并且有人声称通过提供坚固的三柱固定可以增强融合并控制椎体前方的生长；但对于仍有较高生长潜力和高生长速度的儿童必须谨慎。
