Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
J Neurosurg Spine. 2013 May;18(5):472-8. doi: 10.3171/2013.2.SPINE12633. Epub 2013 Mar 22.
Minimally invasive decompressive surgery using a microscope or endoscope has been widely performed for the treatment of lumbar spinal canal stenosis (LSS). In this study the authors aimed to assess outcomes following microscopic bilateral decompression via a unilateral approach (MBDU) in terms of postoperative bone regrowth and preservation of the facet joints in patients with degenerative lumbar spondylolisthesis (DS) as compared with those in patients with LSS.
In the period from May 1998 to February 2007 at the authors' institution, 85 patients underwent MBDU at L4-5. Clinical outcome was evaluated before surgery and at the final follow-up using the Japanese Orthopaedic Association (JOA) score for low-back pain. The following radiographic parameters were assessed at the L4-5 segment before surgery and at the final follow-up: 1) percentage slip on standing lateral radiographs, 2) percentage slip on dynamic radiographs, 3) disc arc on dynamic radiographs, and 4) percentage of facet joint preservation on CT. Bone regrowth on the ventral and dorsal sides of the facet joint on CT were assessed at the final follow-up.
The cases of 47 patients (23 with DS at L-4 and 24 with LSS at L4-5 without instability) who had a follow-up of at least 2 years were retrospectively reviewed. The improvement ratio in the JOA score, that is, the percentage improvement as indicated by the difference between preoperative and postoperative JOA scores, was not significantly different between patients with DS and LSS. The percentage slip had progressed at the latest follow-up in both groups (1.4% and 1.1%, respectively), and there was no significant difference between the 2 groups. The percentage of facet joint preservation in the DS and LSS groups was 72.8% and 83.4%, respectively, on the approach side and 95.5% and 96.5% on the contralateral side. Facet joint preservation was significantly less on the approach side than on the contralateral side in both groups. The average amount of bone regrowth on the dorsal and ventral sides of the facet joint was 3.4 and 0.9 mm, respectively, in the DS group and 2.0 and 1.0 mm in the LSS group. The difference between the 2 groups was not significant. Facet joint preservation and bone regrowth were not correlated with clinical outcomes.
Microscopic bilateral decompression via a unilateral approach can prevent postoperative spinal instability because of good preservation of the posterior elements including the facet joints, which is thought to be the main reason for the relatively small amount of bone regrowth after surgery.
显微镜或内镜辅助下的微创减压术已广泛应用于治疗腰椎管狭窄症（LSS）。本研究旨在评估单侧入路双侧显微镜下减压术（MBDU）治疗退行性腰椎滑脱症（DS）和 LSS 患者的术后骨再生和小关节保护效果。
1998 年 5 月至 2007 年 2 月，作者所在机构对 85 例 L4-5 节段的患者行 MBDU。采用日本骨科协会（JOA）腰痛评分评估术前和末次随访时的临床疗效。评估 L4-5 节段术前和末次随访时的影像学参数：1）站立侧位片滑脱百分比，2）动力位片滑脱百分比，3）动力位片椎间盘弧，4）CT 上小关节面保留百分比。末次随访时，评估 CT 上小关节面腹侧和背侧的骨再生情况。
回顾性分析了 47 例（L4 处 23 例 DS，L4-5 处 24 例无不稳的 LSS）随访至少 2 年的患者。DS 和 LSS 组的 JOA 评分改善率（即术前和术后 JOA 评分差值表示的改善百分比）无显著差异。两组末次随访时滑脱百分比均有所进展（分别为 1.4%和 1.1%），两组间无显著差异。DS 和 LSS 组同侧和对侧小关节面保留百分比分别为 72.8%和 83.4%、95.5%和 96.5%。同侧小关节面保留明显少于对侧，两组间差异有统计学意义。DS 组小关节面腹侧和背侧骨再生平均量分别为 3.4 和 0.9mm，LSS 组分别为 2.0 和 1.0mm，两组间差异无统计学意义。小关节面保留和骨再生与临床结果无相关性。
单侧入路双侧显微镜下减压术能防止术后脊柱不稳，这主要是由于后路结构，包括小关节，得到了很好的保留，术后骨再生量较小。
