後頭骨螺子固定システムを用いた後頭頚・胸椎固定術の手術成績

Occipito-cervico-thoracic Fusion with Four Different Occipital Screw Systems

　後頭骨頚・胸椎固定術を施行した17例，平均63.1歳の手術成績を調査した．疾患は関節リウマチ(RA)12例，腫瘍2例，歯突起骨2例，外傷1例であった．RA例は半数がRanawat分類で1段階以上，他はJOAスコア10.7点が12.3点に改善，後頭部痛VASは8.9点が2.9点になった．合併症は深部感染2例，採骨部感染1例，嚥下困難1例が生じた．後頭骨螺子の脱転1例，弛みを3例に認めた．脱転した螺子は円筒形であり，bi-cortical screwingに加え，手ぶれなく円筒状に骨孔を作成することが重要である．

　The postoperative results of seventeen occipito-cervical (thoracic) fusions that were achieved with four different posterior spinal instrumentations were evaluated.　The causative disease was rheumatoid arthritis (RA) in 12 cases, os odontoideum in 2, a tumor in 2 cases and a fracture in 1.　The fusion rate was 83%.　The neurological status after surgery improved in half of RA patients, and in all of the patients with diseases other.　Occipital headaches decreased in all cases.　Occipital screw dislodgement occurred in one patient and required revision in three other patients, the occipital screw loosening occurred.　Other complications included two deep infections, one iliac crest infection and mortality.　All these complications were occurred in RA.　In conclusion, the occipital plate and screw instrumentation is effective.　However, the occipital screw might not be rigid enough in osteoporotic RA patients.