片開き式頚部脊柱管拡大術に使用したハイドロキシアパタイトスペーサーの骨癒合に対する検討

Union of Hydroxyapatite Spacer for Expansive Open-Door Laminoplasty

　抄録：片開き式頚部脊柱管拡大術に使用したハイドロキシアパタイトスペーサー（以下HAスペーサー）の骨癒合の程度と，骨癒合に影響を与える因子について検討した．対象は術後6カ月以上経過した男性10例，女性6例であり，平均年齢は64.9歳，術後経過観察期間は平均12カ月である．HAスペーサーは75椎弓のうち43椎弓に使用した．各椎弓における骨癒合の判定にはCTを用いた．また，椎弓ごとでの骨癒合に影響を与える因子を検討した．さらに症例ごとでも骨癒合の程度により2群に分類し比較検討した．調査時，各椎弓において骨癒合は39.5％（17椎弓）に認められた．また，HAスペーサーの拡大幅が大きいほど骨癒合が多く，さらに下位椎弓に設置されたものに骨癒合が多かった．症例による骨癒合の程度の差で，JOAスコアや術後の項肩部痛に違いを認めなかったが，術後経過日数の長い症例に骨癒合が多かった．

　We studied the degree of union and factors affecting the union of hydroxyapatite (HA) spacers used for expansive open-door laminoplasty. The subjects were 10male and 6 female patients who were followed for more than 6months. The mean age of the patients was 64.9 years, and the mean follow-up period was 12months. An HA spacer was used for 43 out of 73 laminas. We evaluated the degree of union in each lamina using computed tomography and studied the factors affecting union in each of the laminas and cases. The final rate of union was 39.5％ (17 laminas). HA spacers with a longer width used for lower laminas showed a high frequency of union. Differences in the degree of union in each case were not affected by the JOA score or postoperative pain in the nuchal or shoulder regions. Cases with longer follow-up periods showed a higher frequency of union than cases with a short follow-up period.