BACKGROUND The current classifications of adolescent idiopathic scoliosis (AIS) aim to guide surgical decision making. However, variance exists within treatment recommendations and suboptimal outcomes have been observed while following these guidelines based on two-dimensional images. We used previously developed 3D classification for right thoracic AIS patients and aimed to determine the variation in surgical decision making and the risk of suboptimal outcomes in each subtype according to our classification. METHODS Seventy-six right thoracic AIS patients with 2-year follow-up were included retrospectively. Five 3D preoperative subgroups were determined based on a previous classification system. The upper and lower instrumented vertebrae (UIV and LIV) and the radiographic surgical outcomes at 2-year [frontal balance (FB), proximal junctional kyphosis (PJK), and adding on] were compared between the subtypes. RESULTS The fusion length and the rate of radiographic suboptimal outcomes were statistically different between the five groups. LIV at T12 in Type 1 and UIV at T2 in Type 2 were associated with improved FB and lower PJK, respectively. Type 3 had the highest rate of suboptimal FB and developing PJK. Type 4 had the longest fusion, and suboptimal FB was observed in 42% of the patients independent from the LIV level. Type 5 had the lowest rate of unsatisfactory radiographic outcomes at 2 years. CONCLUSION Following the preoperative 3D classification of the AIS patients, we showed that the UIV and LIV selection has a different impact on the surgical outcomes in each of the five subtypes. The proposed 3D classification has the potential for risk stratification following a posterior spinal surgery in right thoracic AIS. These slides can be retrieved under Electronic Supplementary Material.

中文翻译：

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右胸青少年特发性脊柱侧凸的3D亚型之间的手术结局差异。

背景技术青少年特发性脊柱侧凸（AIS）的当前分类旨在指导手术决策。但是，在治疗建议中存在差异，并且在遵循基于二维图像的这些准则时观察到了次优结果。我们使用先前开发的针对右胸AIS患者的3D分类，旨在根据我们的分类确定手术决策的变化以及每种亚型的次优结局风险。方法回顾性分析76例2年随访的右胸AIS患者。根据先前的分类系统确定了5个3D术前亚组。上侧和下侧椎骨（UIV和LIV）以及2年时的额叶手术影像学结果[额叶平衡（FB），比较了亚型之间的近端结节性驼背（PJK）和添加。结果五组之间的融合长度和放射照相次优结局发生率在统计学上不同。1型T12的LIV和2型T2的UIV分别与改善的FB和较低的PJK相关。3型的次优FB和发育中的PJK发生率最高。4型融合时间最长，与LIV水平无关的42％的患者观察到FB欠佳。5型在2年内射线照相结果满意率最低。结论在对AIS患者进行术前3D分类后，我们显示UIV和LIV选择对这5种亚型中的每种对手术结局都有不同的影响。提出的3D分类具有在右胸AIS进行后路脊柱外科手术后进行风险分层的潜力。这些幻灯片可以在电子补充材料下找到。