Kubo Shinichiro, Goel Vijay K, Yang Seok-Jo, Tajima Naoya
Department of Orthopedic Surgery, Miyazaki Medical College, Miyazaki, Japan.
Spine (Phila Pa 1976). 2003 Feb 1;28(3):227-34. doi: 10.1097/01.BRS.0000042246.09816.20.
In vitro three-dimensional kinematic changes after double-door cervical laminoplasty, with and without spacer, and laminectomy were studied in a human cadaveric model.
To evaluate the effects of multilevel double-door laminoplasty and laminectomy as compared with the intact and to assess the influence of the spinous process spacer on the stability of the cervical spine.
Double-door type cervical laminoplasty has been widely used in the treatment of multisegmental stenotic conditions. However, its biomechanical advantages over laminectomy remain controversial. Also, the biomechanical effects of spacers between the split laminae have not been investigated.
Using fresh cadaveric C2-T1 specimens, sequential injuries were created in the following order: intact, double-door laminoplasty (C3-C6) with insertion of hydroxyapatite spacers, laminoplasty without spacer, and laminectomy. Motions of each vertebra in each injury status were measured in six loading modes: flexion, extension, right and left lateral bending, and right and left axial rotation.RESULTS Cervical laminectomy showed significant increase in motion compared with intact control in flexion [25% (P < 0.001)], extension [19% (P < 0.05)], and axial rotation [24% (P < 0.001)] at maximum load. Double-door laminoplasty with hydroxyapatite spacer indicated no significant difference in motion in all loading modes compared with intact. Laminoplasty without spacer showed intermediate values between laminoplasty with spacer and laminectomy in all loading modes. Initial slack of each injury status showed trends similar to that of maximum load, although mean percent changes of laminectomy and laminoplasty without spacer were greater than that of maximum load.
Double-door laminoplasty with hydroxyapatite spacer appears to restore the motion of the decompressed segment back to its intact state in all loading modes. The use of HA spacers well contributes to maintaining the total stiffness of cervical spine. In contrast, laminectomy seems to have potential leading postoperative deformity or instability.
在人体尸体模型中研究了双开门颈椎板成形术（有无椎间融合器）和椎板切除术术后的体外三维运动学变化。
评估多节段双开门颈椎板成形术和椎板切除术与完整状态相比的效果，并评估棘突间融合器对颈椎稳定性的影响。
双开门式颈椎板成形术已广泛应用于多节段狭窄性疾病的治疗。然而，其相对于椎板切除术的生物力学优势仍存在争议。此外，劈开的椎板间融合器的生物力学效应尚未得到研究。
使用新鲜的尸体C2 - T1标本，按以下顺序进行连续损伤：完整状态、插入羟基磷灰石椎间融合器的双开门颈椎板成形术（C3 - C6）、无椎间融合器的颈椎板成形术和椎板切除术。在六种加载模式下测量每种损伤状态下每个椎体的运动：前屈、后伸、左右侧屈以及左右轴向旋转。
与完整对照组相比，颈椎椎板切除术在最大负荷下的前屈[25%（P < 0.001）]、后伸[19%（P < 0.05）]和轴向旋转[24%（P < 0.001）]运动显著增加。插入羟基磷灰石椎间融合器的双开门颈椎板成形术在所有加载模式下与完整状态相比运动无显著差异。无椎间融合器的颈椎板成形术在所有加载模式下的运动值介于有椎间融合器的颈椎板成形术和椎板切除术之间。每种损伤状态的初始松弛度显示出与最大负荷相似的趋势，尽管椎板切除术和无椎间融合器的颈椎板成形术的平均百分比变化大于最大负荷时的变化。
插入羟基磷灰石椎间融合器的双开门颈椎板成形术似乎在所有加载模式下都能将减压节段的运动恢复到完整状态。使用羟基磷灰石椎间融合器有助于维持颈椎的整体刚度。相比之下，椎板切除术似乎有导致术后畸形或不稳定的潜在风险。
