Background: 

The selection of the lowest instrumented vertebra (LIV) in patients with adolescent idiopathic scoliosis (AIS) is still controversial. Although multiple radiographic methods have been proposed, there is no universally accepted guideline for appropriate selection of the LIV. We developed a simple and reproducible method for selection of the LIV in patients with Lenke type-1 (main thoracic) and 2 (double thoracic) curves and investigated its effectiveness in producing optimal positioning of the LIV at 5 years of follow-up.

Methods: 

The radiographs for 299 patients with Lenke type-1 or 2 AIS curves that were included in a multicenter database were evaluated after a minimum duration of follow-up of 5 years. The “touched vertebra” (TV) was selected on preoperative radiographs by 2 independent examiners. The LIV on postoperative radiographs was compared with the preoperative TV. The final LIV position in relation to the center sacral vertical line (CSVL) was assessed. The CSVL-LIV distance and coronal balance in patients who had fusion to the TV were compared with those in patients who had fusion cephalad and caudad to the TV. The sagittal plane was also reviewed.

Results: 

In 86.6% of patients, the LIV was selected at or immediately adjacent to the TV. Among patients with an “A” lumbar modifier, those who had fusion cephalad to the TV had a significantly greater CSVL-LIV distance than those who had fusion to the TV (p = 0.006) or caudad to the TV (p = 0.002). In the groups with “B” (p = 0.424) and “C” (p = 0.326) lumbar modifiers, there were no differences among the TV groups.

Conclusions: 

We recommend the TV rule as a third modifier in the Lenke AIS classification system. Selecting the TV as the LIV in patients with Lenke type-1 and 2 curves provides acceptable positioning of the LIV at long-term follow-up. The position of the LIV was not different when fusion was performed caudad to the TV but came at the expense of fewer motion segments. Patients with lumbar modifier “A” who had fusion cephalad to the TV had greater translation of the LIV, putting these patients at risk for poor long-term outcomes.

Level of Evidence: 

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

---

选择“接触型椎骨”作为Lenke 1型和2型曲线患者的最低仪器化椎体：最少随访5年的放射照相结果

背景： 

在青少年特发性脊柱侧凸（AIS）患者中，选择最低器械椎骨（LIV）仍存在争议。虽然已经提出了多种影像学方法，没有普遍接受的准则为LIV的适当选择。我们开发了一种简单且可重现的方法，用于选择Lenke 1型（主胸）和2型（双胸）曲线的患者的LIV，并研究了其在随访5年中对LIV进行最佳定位的有效性。

方法： 

经过至少5年的随访，对多中心数据库中包括的299例Lenke 1型或2 AIS曲线患者的X光片进行了评估。两名独立检查员在术前X光片上选择了“触摸椎骨”（TV）。将术后X光片上的LIV与术前TV进行比较。评估相对于骨中央垂直线（CSVL）的最终LIV位置。将电视融合的患者的CSVL-LIV距离和日冕平衡与头颅融合并融合到电视的患者进行了比较。还对矢状面进行了检查。

结果： 

在86.6％的患者中，LIV是在电视上或电视附近选择的。在具有“ A”型腰椎改良器的患者中，与电视融合头枕的患者的CSVL-LIV距离明显大于与电视融合（p = 0.006）或因电视融合（p = 0.002）的患者。在具有“ B”（p = 0.424）和“ C”（p = 0.326）腰部修饰符的组中，电视组之间没有差异。

结论： 

我们建议将电视规则作为Lenke AIS分类系统中的第三个修饰符。选择Lenke 1型和2型曲线患者的电视作为LIV，可以在长期随访中将LIV定位为可接受的位置。当在电视上进行融合时，LIV的位置没有变化，但这是以减少运动段为代价的。融合了电视头枕的腰椎“ A”型患者的LIV移位更大，使这些患者面临长期预后不良的风险。

证据级别： 

治疗级别III。有关证据水平的完整说明，请参见《作者说明》。