腰椎変性すべり症に対するBAK ProximityケージとLumbar Alligator Spinal Systemを用いた後方進入腰椎椎体間固定術

Posterior Lumbar Interbody Fusion Using BAK Proximity Cages and the Lumbar Alligator Spinal System for Degenerative Spondylolisthesis of the Lumbar Spine

　47例の腰椎変性すべり症に対して棘突起を左右から挟むプレートであるLumbar Alligator Spinal System（LA）とネジ型ケージを用いた後方進入腰椎椎体間固定術を行った．2年以上の追跡で骨癒合率は97.9％，日整会スコア改善率は81％であった．3例に棘突起骨折を認め，2例で骨癒合が遷延化した．LA装着は簡便で，椎弓根スクリューのような誤刺入の危険性はない．さらに軟部組織の側方展開も少なくて済むという利点があり，腰椎固定の選択肢の1つとなりうることが示された．

　Although posterior lumbar interbody fusion (PLIF) using threaded cages alone is a useful procedure in our experience, the rate of union achieved by this operation has not been very high. The Lumbar Alligator Spinal System (LA) is a clamping plate for the spinous processes that has been developed to provide supporting instrumentation for this procedure. Single-level posterior lumbar interbody fusion using the LA and BAK Proximity Cages was performed in 47 patients with degenerative spondylolisthesis. Mean age at the time of surgery was 66.0 years, and the follow-up period was more than 24 months (average：35.6 months). Solid union was defined as bony bridging between two vertebral bodies on plain radiograms. Solid union was achieved in 46 patients (97.9％) as of two years after surgery. The LA is a useful instrument for PLIF using threaded cages.