Clinical and radiographic outcomes of upper thoracic versus lower thoracic upper instrumented vertebrae for adult scoliosis: a meta-analysis

The aim of this study was to evaluate the clinical and radiographic outcomes of upper thoracic (UT) versus lower thoracic (LT) upper instrumented vertebrae (UIV) for adult scoliosis by meta-analysis. We conducted a literature search in three databases to retrieve related studies up to March 15, 2017. The preliminary screened studies were assessed by two reviewers according to the selection criteria. All analyses were carried out using the statistical software package R version 2.31. Odds ratios (OR) with 95% confidence intervals (CI) were used to describe the results. The I2 statistic and Q statistic test were used for heterogeneity assessment. Egger's test was performed to detect publication bias. To assess the effect of each study on the overall pooled OR or standardized mean difference (SMD), sensitive analysis was conducted. Ten trials published between 2007 and 2015 were eligible and included in our study. Meta-analysis revealed that the UT group was associated with more blood loss (SMD=0.4779, 95%CI=0.3349-0.6209, Z=6.55, P<0.0001) and longer operating time (SMD=0.5780, 95%CI=0.1971-0.958, Z=2.97, P=0.0029) than the LT group. However, there was no significant difference in Oswestry Disability Index, Scoliosis Research Society (SRS) function subscores, radiographic outcomes including sagittal vertical axis, lumbar lordosis, and thoracic kyphosis, length of hospital stay, and revision rates between the two groups. No evidence of publication bias was found between the two groups. Fusion from the lower thoracic spine (below T10) has as advantages a shorter operation time and less blood loss than upper thoracic spine (above T10) in posterior long-segment fixation for degenerative lumbar scoliosis.

本研究旨在通过荟萃分析（meta-analysis），对比成人脊柱侧凸（adult scoliosis）术中采用上胸椎（upper thoracic, UT）与下胸椎（lower thoracic, LT）作为上端固定椎（upper instrumented vertebrae, UIV）的临床及影像学结局。我们于2017年3月15日前，在3个数据库中开展文献检索以获取相关研究。由2名评价者依据纳入排除标准（selection criteria）对初步筛选出的研究进行评估。所有分析均采用统计软件R版本2.31完成。采用比值比（Odds ratios, OR）与95%置信区间（95% confidence intervals, CI）描述研究结果。使用I²统计量与Q检验进行异质性评价（heterogeneity assessment）。采用埃格检验（Egger's test）检测发表偏倚（publication bias）。为评估每项研究对合并后总比值比或标准化均数差（standardized mean difference, SMD）的影响，我们开展了敏感性分析（sensitive analysis）。最终纳入2007年至2015年间发表的10项符合标准的试验。荟萃分析结果显示，相较于下胸椎组，上胸椎组的失血量更多（SMD=0.4779，95%CI=0.3349-0.6209，Z=6.55，P<0.0001），手术时长更长（SMD=0.5780，95%CI=0.1971-0.958，Z=2.97，P=0.0029）。然而，两组在奥斯维斯特里功能障碍指数（Oswestry Disability Index）、脊柱研究学会（Scoliosis Research Society, SRS）功能分项评分、包括矢状垂直轴（sagittal vertical axis）、腰椎前凸（lumbar lordosis）及胸椎后凸（thoracic kyphosis）在内的影像学结局、住院时长（length of hospital stay）及翻修率（revision rates）方面均无显著差异。两组未发现存在发表偏倚的证据。在退行性腰椎侧凸（degenerative lumbar scoliosis）的后路长节段固定（posterior long-segment fixation）术中，采用T10以下的下胸椎作为固定节段，相较T10以上的上胸椎，可获得更短的手术时长与更少的术中失血量。