Banno Tomohiro, Yamato Yu, Oba Hiroki, Ohba Tetsuro, Hasegawa Tomohiko, Yoshida Go, Arima Hideyuki, Oe Shin, Mihara Yuki, Ushirozako Hiroki, Takahashi Jun, Haro Hirotaka, Matsuyama Yukihiro
1Department of Orthopaedic Surgery, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka.
2Department of Orthopaedic Surgery, Shinshu University, Matsumoto, Nagano; and.
J Neurosurg Spine. 2021 Jul 9;35(3):330-339. doi: 10.3171/2020.11.SPINE201807. Print 2021 Sep 1.
L3 is most often selected as the lowest instrumented vertebra (LIV) to conserve mobile segments in fusion surgery; however, in cases with the lowest end vertebra (LEV) at L4, LIV selection as L3 could have a potential risk of correction loss and coronal decompensation. This study aimed to compare the clinical and radiographic outcomes depending on the LEV in adolescent idiopathic scoliosis (AIS) patients with Lenke type 5C curves.
Data from 49 AIS patients with Lenke type 5C curves who underwent selective thoracolumbar/lumbar (TL/L) fusion to L3 as the LIV were retrospectively analyzed. The patients were classified according to their LEVs into L3 and L4 groups. In the L4 group, subanalysis was performed according to the upper instrumented vertebra (UIV) level toward the upper end vertebra (UEV and 1 level above the UEV [UEV+1] subgroups). Radiographic parameters and clinical outcomes were compared between these groups.
Among 49 patients, 32 and 17 were in the L3 and L4 groups, respectively. The L4 group showed a lower TL/L curve correction rate and a higher subjacent disc angle postoperatively than the L3 group. Although no intergroup difference was observed in coronal balance (CB), the L4 group showed a significantly higher main thoracic (MT) and TL/L curve progression during the postoperative follow-up period than the L3 group. In the L4 group, the UEV+1 subgroup showed a higher absolute value of CB at 2 years than the UEV subgroup.
In Lenke type 5C AIS patients with posterior selective TL/L fusion to L3 as the LIV, patients with their LEVs at L4 showed postoperative MT and TL/L curve progression; however, no significant differences were observed in global alignment and clinical outcome.
在融合手术中，L3常被选作最低融合椎体（LIV）以保留活动节段；然而，在最低终椎（LEV）位于L4的病例中，选择L3作为LIV可能存在矫正丢失和冠状面失代偿的潜在风险。本研究旨在比较青少年特发性脊柱侧凸（AIS）Lenke 5C型曲线患者中，根据LEV不同所产生的临床和影像学结果。
回顾性分析49例接受选择性胸腰段/腰段（TL/L）融合至L3作为LIV的Lenke 5C型曲线AIS患者的数据。根据LEV将患者分为L3组和L4组。在L4组中，根据上融合椎体（UIV）至上端椎（UEV及UEV上一个节段[UEV+1]亚组）的水平进行亚分析。比较这些组之间的影像学参数和临床结果。
49例患者中，L3组和L4组分别有32例和17例。L4组术后TL/L曲线矫正率低于L3组，相邻椎间盘角度高于L3组。虽然在冠状面平衡（CB）方面未观察到组间差异，但L4组在术后随访期间主胸弯（MT）和TL/L曲线进展明显高于L3组。在L4组中，UEV+1亚组在2年时的CB绝对值高于UEV亚组。
在Lenke 5C型AIS患者中，后路选择性TL/L融合至L3作为LIV，LEV位于L4的患者术后MT和TL/L曲线有进展；然而，在整体对线和临床结果方面未观察到显著差异。
