Sato Masatsune, Uesugi Masaaki, Kawai Takuya, Kobayashi Yosuke, Aota Yoichi
Department of Orthopaedic Surgery, National Hospital Organisation Yokohama Medical Center, Yokohama, Japan.
Department of Orthopaedic Surgery, International University of Health and Welfare, University Atami Hospital, Atami, Japan.
Spine Surg Relat Res. 2022 Oct 28;7(2):170-178. doi: 10.22603/ssrr.2022-0105. eCollection 2023 Mar 27.
Patients with adult spinal deformity (ASD) develop compensatory mechanisms. The Cobb angle between T4 and T12 has been used as a standard to define thoracic kyphosis (TK) because radiological evaluation is difficult in upper thoracic region. The upper thoracic compensatory mechanism has not been sufficiently explored, and focal thoracic compensation remains poorly understood. This study aimed to determine upper sagittal thoracic compensation and features of thoracic compensation in ASD patients.
The records of 218 consecutive patients who underwent full-standing EOS imaging were retrospectively examined. Spinopelvic parameters-including the T1-T12, T4-T12, T1-T4, T5-T8, and T9-T12 angles-were measured using a dedicated and validated software. The relationship between the thoracic and spinopelvic parameters was statistically evaluated. Thoracic compensation was compared among four typical types of spinal deformity.
A total of 127 ASD patients met the inclusion criteria. TK(1-12) was negatively correlated with the sagittal vertical axis (SVA) (r=-0.35), T1 pelvic angle (TPA) (r=-0.29), and pelvic incidence minus lumbar lordosis (PI-LL) (r=-0.60). TK(1-4) showed a stronger correlation with the SVA and TPA than TK(5-8) or TK(9-12) (r=-0.39, -0.38, respectively). TK(1-4), TK(5-8), and TK(9-12) had a similar negative correlation with PI-LL; however, TK(5-8) had the strongest correlation (r=-0.38). Both age and TK(9-12) were significantly associated with decreased TK(1-4), and vertebral fracture was significantly associated with increased TK(9-12). Both patients with high SVA and those in the hyperthoracic kyphosis group had lower TK(1-4) angles.
In ASD patients, upper thoracic spine compensation plays an important role in countering global malalignment. The middle part of the thoracic spine has a strong correlation with LL. This study findings can help clinicians better manage ASD patients.
成人脊柱畸形（ASD）患者会形成代偿机制。由于上胸椎区域的影像学评估困难，T4与T12之间的Cobb角已被用作定义胸椎后凸（TK）的标准。上胸椎代偿机制尚未得到充分探索，局部胸椎代偿仍知之甚少。本研究旨在确定ASD患者的上矢状面胸椎代偿情况及胸椎代偿特征。
回顾性检查218例接受全站立位EOS成像的连续患者的记录。使用专门的经过验证的软件测量脊柱骨盆参数，包括T1-T12、T4-T12、T1-T4、T5-T8和T9-T12角。对胸椎和脊柱骨盆参数之间的关系进行统计学评估。比较四种典型脊柱畸形类型之间的胸椎代偿情况。
共有127例ASD患者符合纳入标准。TK(1-12)与矢状垂直轴（SVA）（r=-0.35）、T1骨盆角（TPA）（r=-0.29）以及骨盆入射角减去腰椎前凸（PI-LL）（r=-0.60）呈负相关。TK(1-4)与SVA和TPA的相关性比TK(5-8)或TK(9-12)更强（分别为r=-0.39和-0.38）。TK(1-4)、TK(5-8)和TK(9-12)与PI-LL均呈相似的负相关；然而，TK(5-8)的相关性最强（r=-0.38）。年龄和TK(9-12)均与TK(1-4)降低显著相关，椎体骨折与TK(9-12)增加显著相关。高SVA患者和胸椎后凸过大组患者的TK(1-4)角均较低。
在ASD患者中，上胸椎代偿在对抗整体排列不齐方面起重要作用。胸椎中部与腰椎前凸有很强的相关性。本研究结果可帮助临床医生更好地管理ASD患者。
