側弯症手術におけるフリーハンド胸椎椎弓根スクリュー刺入法の検討―PLP（Palpation of Lateral Wall of Pedicle）法を用いて

Clinical Results of Free-hand Pedicle Screw Placement by the Palpation of Lateral Wall of Pedicle (PLP) Method for Scoliosis Surgery

　側弯症患者45名に対する後方矯正固定術におけるpalpation of lateral wall of pedicle(PLP)法を用いたフリーハンドによる胸椎椎弓根スクリューの刺入精度，臨床成績を調査した．スクリューの逸脱率は7.5％，刺入角度が原因のものが76.9％であった．逸脱した症例では術前主カーブが有意に大きかったが，矯正率には差がなかった．スクリュー刺入に伴う合併症はなかった．PLP法は刺入位置の決定には有用であるが，刺入角度の決定には今後の検討が必要である．

Purpose：To evaluate the accuracy of thoracic pedicle screw (TPS) placement by the palpation of the lateral wall of the pedicle (PLP) method.

Methods：The subjects of this study were 45 scoliosis patients.　The accuracy of TPS placement was evaluated by postoperative CT.

Results：Of the 348 TPSs inserted, 26 (7.5%) breached the pedicle wall.　Of the 26 misplaced screws, 20 were inserted on the wrong trajectory, and 6 were inserted at the wrong insertion point.　The preoperative major Cobb angle averaged 70.4° in the group with pedicle perforation by the TPS, and 54.1° in the group with correct placement of the TPS (p＝0.006).　No intra- or post-operative complications developed as a result of the pedicle perforation.

Conclusion：The PLP method is useful in deciding on the correct insertion point,but it is of no assistance in inserting screws along the correct trajectory.　This,it will be necessary to improve the technique of determining the correct trajectory for the TPS.