Hybrid頚椎片開き式拡大椎弓形成術の試み

The Hybrid Laminoplasty of the Cervical Spine

　抄録：われわれはHAスペーサーと棘突起を利用した自家骨スペーサーを交互に拡大椎弓に挿入・固定するHybrid片開き式拡大術（以下Hybrid拡大術）を発案し，今回，その術後成績と本法の利点，意義について検討した．対象は1997年以降にHybrid拡大術を施行した108例（男78例，女30例）である．最終診察時の手術成績はJOAスコア（17点法）14.7点，改善率は68.1％であり良好であった．また，頚椎弯曲指数において術前後のアライメントに有意差はなかった．CTによる骨癒合判定では，自家骨スペーサーが早期に癒合し，HAスペーサーにより形成された椎孔を，構築学的に補強，安定化させていた．Hybrid拡大術は利点としてHAスペーサーによる良好な椎弓形態の獲得・保持と，自家骨スペーサーの早期で確実な骨癒合による安定化という双方の長所を取り入れられる点である．Hybrid拡大術は臨床的，構築学的にも長期に良好な手術成績が維持されるものと考える．

　We developed the new method of cervical expansive open-door laminoplasty (hybrid laminopasty) in which hydroxyapatite (HA) spacers and bone spacers made from spinous processes were inserted and fixed at open door side alternately. We investigated the postoperative results of the hybrid laminoplasty. This study included 108 patients (78males, 30 females) who underwent the hybrid laminoplasty since 1997. Concerning the results of surgery on the final consultation, the JOA score (17-points method) was averaged 14.7, and improvement rate was averaged 68.1％. From the radiographic study, there were no significant changes in the cervical lateral curvature index after surgery. We evaluated the bony fusion between laminas and spacers using CT, the bone spacers achieved early and reliable union was found. Also we considered the reinforcement of vertebral laminas which were constructed by HA spacers were facilitated by bone spacers. The hybrid laminoplasty has combined advantages of two kinds of lamina spacers. These advantages are the ideal construction of vertebral canal with the HA spacers and the early stabilization of the vertebral lamina with the bone spacers related to early bony fusion. We consider that the hybrid laminoplasty can achieve the long-term good surgical results.