经皮侧后路腰椎间孔成形术对腰椎解剖及生物力学影响的实验研究

目的 研究经侧后路腰椎间孔逐级扩大成形术对腰椎解剖及腰椎稳定性的影响.方法 6具人脊柱功能单位（L4-5）新鲜尸体标本,依次用外直径为7.5mm和10mm的环锯对脊柱运动节段右侧椎间孔下半部分进行扩大成形,观察不同直径环锯对腰椎间孔扩大成形后解剖学变化.用脊柱三维运动试验机（MTS 858MiniBionix Test system,Minneapolis,MN）测量脊柱功能单位在椎间孔成形前后腰椎稳定性,包括未加载时中性区的位 置及加载10.0N.m后脊柱功能单位的屈伸、侧屈及轴向旋转范围等指标.结果 使用外直径7.5mm的环锯对腰椎间孔进行扩大成彤时,仪切除L5上关节突腹外侧部分骨性结构,而对关节突关节的关节面及关节囊无任何破坏,腰椎稳定性无明显改变;使用外直径10mm环锯对腰椎间孔进行扩大成形后,L5上关节突腹外侧骨质被部分切除,同时上关节突尖部及部分关节面、腹侧关节囊被一并切除.腰椎侧屈稳定性明显降低.结论 腰椎间孔扩大成形幅度过大,可降低脊柱功能单位的侧屈稳定性,但无明显破坏.

Anatomical and biomechanical impact of graded posterolateral foraminoplasty on lumbar spine

Objective To study the anatomical and biomechanical impact of graded posterolateral foraminoplasty on lumbar spinal segment. Methods Six fresh, human cadaveric, two-vertebrae （L4-5）, functional spinal units （FSU） were used to study the pathoanatomy and stability changes after posterolateral foraminoplasty with 7.5tore- diameter trephine and 10mm-diameter trephine respectively. The position of neutral zone without loading and the range of motion of flexion, extension, left bending; right bending, left axial rotation and right axial rotation with 10.0N.m loading were determined and compared with a normalized stability for the specimen when intact on three-dimension spinal ROM testing system （MTS 858 Mini-Bionix Test System, Minneapolis, MN）. Results Only partial ventrolateral bony structure of superior articular process was resected after first-grade posterolateral foraminoplasty with 7.5mm- diameter trephine while all the articular surface and articular capsule were kept intact and stability of FSU was not significantly changed compared with that before surgery. The upper half of the superior articular process and the partial ventral articular capsule were resected after second-grade posterolateral foraminoplasty with 10mm-diameter trephine and lateral bending flexibility of FSU was significantly increased compared with that before surgery. Conclusions Limited posterolateral foraminoplasty without impairment to articular surface and capsule of zygapophysial joint will not impair lumbar stability. Overly enlarged posterolateral foraminoplasty with impairment to the upper half of the superior articular process and the ventral articular capsule will significantly decrease the stability of lateral bending, although intervertebral foramen and lateral recess of lumbar spinal canal can be effectively decompressed.