腰椎変性疾患に対するmonoportal PLIFの手術成績

Operative Results of Monoportal PLIF Surgery for Lumbar Degenerative Disease

　当科で施行した単椎間monoportal PLIFの手術成績を調査した．％slipは術前22.9±7.6％が術後1年で13.7±7.5％，disc angleは術前4.5±7.5°が術後1年で7.2±4.7°に改善した．手術時間は214±25分，術中出血量は143±96mlであり，麻痺悪化1例と偽関節の1例に再手術を施行した．JOAスコアは術前14.5±4.9点が術後1年で25.5±3.0点に改善し，改善率は76％であった．術後1年の時点で45例中33例にcage前方の移植骨の連続性が認められ骨癒合と判定した．Cageの沈下は2例，4.4％に認められた．片側より椎体間固定を行うmonoportal PLIFは硬膜外血管，神経組織に対し低侵襲であり，従来のPLIFに比べ遜色ない成績が得られた．

　We evaluated the operative outcomes of single-level monoportal PLIF (posterior lumbar interbody fusion) performed at our hospital. The percentage of slippage (％slip) of the upper vertebra before operation was 22.5±7.6％；this value decreased to 13.7±7.5％ after one postoperative year. The preoperative disc angle was 4.5±7.5 degrees；this value improved to 7.2±4.7 degrees after one postoperative year. The operation time was 214±25 minutes, and the intraoperative blood loss was 143±96 ml. Reoperation was performed in one case with neurological deterioration and one case with pseudoarthrosis. The JOA (Japanese Orthopaedic Association) score improved from 14.5±4.9 points preoperatively to 25.5±3.0 points one year postoperatively, and the average percentage of improvement was 76％. Thirty-three out of 45 cases were judged to have complete bony fusion based on the appearance of a solid bony mass in front of cages on X-ray images. The subsidence of cage was recognized in 3 cases (6.7％). Monoportal PLIF in less invasive with regard to the vessels and nerves and can attain an operative outcome similar to that of PLIF.