頚部脊髄症に対する片開き式脊柱管拡大術―術前頚椎アライメントから見た特徴と手術成績について

Expansive Open-Door Laminoplasty for Cervical Myelopathy : Characteristics of Pre-Operative Cervical Alignment and Surgical Results

　抄録：頚部脊髄症に対し片開き式脊柱管拡大術を施行した75例を，術前の頚椎アライメントから直線型（S型：14例），前弯型（L型：42例），前弯増強型（HL型：19例）に分類し，それらの臨床像の特徴や手術成績について3群間で比較検討した．前弯増強型では高齢者が多く，短期間で症状が進行する傾向にあり，術前重症度が高く，脊髄圧迫，椎間不安定性は上位椎間に生じる傾向にあった．しかし発症後速やかに手術を行うことによって，高齢者といえども良好な回復が期待でき，術後のアライメント変化は，前弯が減少しても直線，後弯型に移行することがなく，通常の片開き式拡大術のよい適応であると考えられた．一方，S型は手術時年齢が若く，術前重症度は低い傾向にあった．しかし術前後とも可動域が大きく，椎間不安定性を有する例は，術後予想以上に後弯変形が進行し，成績悪化に繋がる可能性があり，症例によっては固定術の併用も考慮すべきと思われた．

　Seventy-five patients who underwent expansive open-door laminoplasty for cervical myelopathy were divided into three groups according to the findings of preoperative cervical alignment：straight alignment (type S, n＝14), lordosis (type L, n＝42), and hyperlordosis (type HL, n＝19). The characteristics and surgical results of these three groups were compared. Type HL was characterized by a large proportion of elderly subjects, a tendency of symptom progression within a short period, high preoperative severity, spinal cord compression and a tendency of intersegmental instability in the upper vertebrates. However, if surgeries were carried out promptly after symptom onset, good recovery could be expected even in elderly subjects. After surgery, cervical alignment showed reduction of lordosis, but no progression to straight or kyphotic cervical alignment. These cases were considered to be good indication for expansive open-door laminoplasty. On the other hand, type S was characterized by a large proportion of young subjects and a tendency of low preoperative severity. However, in cases with large pre and post-operative ranges of motion and intersegmental instability, kyphotic deformity progressed beyond expectation after surgery. Since this might lead to poor outcome, combined fixation should be considered depending on patients.