腰椎峡部骨性解剖特点及其临床意义

目的 了解腰椎后外侧部骨性结构变化特点,为峡部外缘入路摘除极外侧腰椎间盘突出提供解剖依据.方法 在30侧湿性成人腰椎标本上测量:(1)峡部外缘至中线的距离;(2)椎体腰部外缘面至后正中线的距离;(3)峡腰距;(4)关节突上缘与横突下缘间距;(5)关节突上缘与副突间距;(6)关节突上缘与间盘中心面的相对距离,并分析其随腰椎序列变化的规律.结果 随着腰椎序数的增加,在下腰椎,代表"手术窗"横向径线的峡腰距在L5减少为0.32 cm(P＜0.05);纵向径线关节突上缘与横突下缘间距和关节突上缘与副突间距亦递减,在L5-S1分别为0.17 cm和0.46 cm(P＜0.05),造成"手术窗"外口缩窄.而关节突上缘与间盘中心面的相对距离渐增加,由L1-2的-0.20cm增至L5-S1的0.86 cm(P＜0.05),关节突渐上移覆盖了间盘平面.结论 从L1-L2至L4-S1,峡部外缘入路显露极外侧腰椎间盘突出时,需要切除的峡部外缘、横突根部、椎弓根下部、关节突关节上部的骨量递增;在L5-S1采取峡部外缘入路时可能造成上述部位的骨量切除过多而致术后腰椎不稳.

Bony anatomical characteristics of posterolateral region of lumbar vertebrae and clinical significance thereof

OBJECTIVE: To offer anatomical supports to the approach of lateral par interarticularis for far lateral lumbar discectomy. METHODS: In 30 lumber spine specimens taken from adult cadavers the relevant osseous distances of posterolateral region of lumbar vertebrae and its changing regularity with the sequences of lumbar spine were measured: (1) width of isthmus; (2) distance from midline to lateral border of vertebral body; (3) distance from lateral margin of isthmus to lateral border of vertebral body; (4) distance from inferior border of transverse process to superior rim of superior facet; (5) distance from accessory process to superior rim of superior facet; and (6) distance from central plane of lumbar disc to superior rim of superior facet. RESULTS: From L1-L2 towards L5-S1, the operative window representing the operating area of the approach of lateral par interarticularis for far lateral lumbar discectomy became progressively smaller in its longitudinal, transverse direction and outer exit. The distance from lateral margin of isthmus to lateral border of vertebral body representing the transverse diameter of the operative window was reduced to 0.32 cm (P < 0.05). While the distance from inferior border of transverse process to superior rim of superior facet and distance from accessory process to superior rim of superior facet representing the longitudinal diameter of operative window were reduced to 0.17 cm and 0.46 cm respectively (both P < 0.05). The distance from central plane of lumbar disc to superior rim of superior facet increased gradually from -0.20 cm in L1-2 to 0.86 cm in L5-S1 (P < 0.05). The articular process extended upward and covered more lumbar disc plane. CONCLUSION: At the level L1-L2 to L4-L5, the lateral par interarticularis approach is an easy, convenient, and anatomically favorable way to reach the far lateral lumbar disc herniation, but the progressive diminution of operative window increases the bony excision in lateral par interarticularis, root of transverse process, inferior portion of pedicle and superior portion of zygapophysial joint. At the level of 15-S1, the operative window becomes very tight. The excess of bone removal and expected instability of lumbar spine make the lateral par interarticularis approach tough to be done.