β-リン酸三カルシウム（β-TCP）を用いた脊椎固定術の骨癒合評価と臨床成績

Evaluation of Bony Fusion and Clinical Outcome after Spinal Fusion with Beta-tricalcium Phosphate

　背景：後側方固定術(PLF)にβ-リン酸三カルシウム(β-TCP)を併用した報告は散見されるが，後方進入腰椎椎体間固定術(PLIF)を併用したPLFにβ-TCPを併用した報告はない．

　対象と方法：PLIFを併用したPLFにβ-TCPを併用した群と局所骨のみの群で骨癒合率と臨床成績を調査した．

　結果：臨床成績は両群に差はなかったが，骨癒合率は多椎間固定ではβ-TCP併用群は局所骨のみの群に比べ有意に増加した．

　まとめ：β-TCPは骨形成の早期の足場として有用な骨補塡材料であると考える．

　Background：β-tricalcium phosphate (β-TCP) has been used as a bone graft substitute for PLF or PLIF, but there have been few reports of PLF with β-TCP combined with PLIF.

　Methods：We assessed bony fusion and the clinical outcome after PLF with β-TCP combined with PLIF.　When the quantity of local bone was insufficient, β-TCP granules were mixed with local bone to perform PLF.　Clinical outcome was evaluated according to the Hirahayashi's recovery rate of Japan Orthopaedic Association (JOA) score.　Bony fusion and clinical outcome were compared in a group treated with β-TCP mixed with local bone (T-group) and a group treated with local bone alone (L-group).

　Outcome：The bony fusion rates in the two groups were not significantly different when fusion was performed at a single level, but the bony fusion rate was significantly higher in the T-group when fusion was performed at more than one level (P＝0.02).　The difference in Hirahayashi's recovery rate of JOA score between the two groups was not significant irrespective of whether fusion was performed at one level or more than one level.

　Conclusions：The results showed that β-TCP can play an important role as a scaffold to achieve bony fusion in multi-level fusion when the quantity of local bone is insufficient.