Li Chun-de, Yu Zheng-rong, Liu Xian-yi, Li Hong
Department of Orthopedics, Beijing University First Hospital, Beijing 100034, China.
Zhonghua Wai Ke Za Zhi. 2006 Feb 15;44(4):246-8.
To investigate the influence factors of adjacent segment degeneration (ASD) after instrumented lumbar fusion.
Thirty-three patients who had undergone an instrumented lumbar fusion from March 1998 to May 2002 were reviewed. The incidence, age, position, radiographic characteristics and clinical manifestations of ASD were studied. Then the relations between "floating fusion" and ASD were compared, the range of fusion and ASD and investigated the incidences of different adjacent segments.
The mean follow-up period for the patients was 4 years and 7 months (24 - 82 months). Adjacent segment degeneration mainly occurred in patients older than 60. Ten patients (10%) were found to have radiographic characteristics of ASD. Nine of the ten patients had ASD at cranial segments. Using "floating fusion" or not did not show difference in the risk of ASD. There was a trend of more ASDs after long-segment fusion than short-segment fusion. As an adjacent segment, L(2)/L(3) had a high risk of ASD, while L(5)/S(1) had a much lower risk.
The cranial segment has a higher degeneration risk than the caudal segment. If L(2)/L(3) has degenerative appearance and has chance to be the adjacent segment, we'd better fuse it. If there is no evidence of obvious degeneration, L(5)/S(1) should not be fused. During instrumented lumbar fusion, long-segment fusion should be avoided if possible.
探讨腰椎融合内固定术后相邻节段退变（ASD）的影响因素。
回顾性分析1998年3月至2002年5月行腰椎融合内固定术的33例患者。研究ASD的发生率、年龄、部位、影像学特征及临床表现。比较“浮动融合”与ASD的关系、融合范围与ASD的关系，并调查不同相邻节段的发生率。
患者平均随访时间为4年7个月（24 - 82个月）。相邻节段退变主要发生在60岁以上患者。10例（10%）患者具有ASD的影像学特征。这10例患者中有9例在头侧节段发生ASD。是否采用“浮动融合”在ASD风险方面无差异。长节段融合后ASD的发生率有高于短节段融合的趋势。作为相邻节段，L(2)/L(3)发生ASD的风险较高，而L(5)/S(1)发生ASD的风险则低得多。
头侧节段的退变风险高于尾侧节段。若L(2)/L(3)有退变表现且有机会成为相邻节段，最好予以融合。若没有明显退变的证据，则不应融合L(5)/S(1)。在腰椎融合内固定术中，应尽可能避免长节段融合。
