頚髄砂時計腫摘出術における椎弓根をヒンジとした新しい脊柱管拡大法

Pedicle-hinged Unilateral Posterior Arch Recapping Technique (P-UPART). A New Surgical Technique for Dumbbell-shaped Cervical Spinal Cord Tumors

　椎弓根部をヒンジとする新しい脊柱管拡大術を用いて頚髄砂時計腫を全摘出した．前方病巣切除は，前側方進入で隣接する2つの横突孔を切除し，椎骨動脈を前方に引き出し，各々の椎弓根も切断して行った．管内病巣の切除には，付着筋を温存したまま棘突起を正中縦割し，椎弓根部をヒンジとして片側椎弓を開大した．利点として，椎骨動脈を直視しながら安全に前方病巣を切除できる，椎弓根部をヒンジとするため，椎弓がより大きく開大し，管内を広く展開できる，椎弓ヒンジ作成が不要のため，後方筋群が完全に温存される，などが挙げられる．

　We macro-totally excised dumbbell-shaped cervical spinal cord tumors by a new surgical procedure in which the unilateral posterior arches are pivoted at the divided pedicles.

　The procedure was performed by an anterolateral approach followed by a posterior approach.　In the first part of the procedure, by the anterior approach, the outer wall of the transverse foramina of the affected vertebrae was removed to dislodge the vertebral artery, and then the inner wall, the pedicle, was divided to widen the exposure of the anterior component of the tumor.　In the second part of the procedure, by the posterior approach, after longitudinally splitting the spinous processes with their attached muscles undisturbed unilateral posterior arches were pivoted at the point of division of each pedicle.

　The advantages of this procedure are:

1. The anterior component of the tumor is securely excised with the vertebral artery kept in control.

2. The intracanalicular space is more widely exposed by pivoting the unilateral posterior arch at the divided pedicle rather than the conventional lateral gutter on the lamina.

3. The posterior musculature is kept undisturbed because lateral gutter on the lamina is totally unnecessary.