Saito Toshiki, Kawakami Noriaki, Tsuji Taichi, Ohara Tetsuya, Suzuki Yoshitaka, Nohara Ayato, Tauchi Ryoji, Kawakami Kazuki
Meijo Hospital Spine Center, Nagoya, Japan.
J Pediatr Orthop. 2018 Apr;38(4):217-222. doi: 10.1097/BPO.0000000000000784.
This is a retrospective cohort study.
Hemimetameric segmental shift (HMMS) is defined as a hemivertebral deformation in which 2 or more hemivertebrae exist on both sides of the spine and are separated by at least 1 normal vertebra. Reports of HMMS are rare and based on simple anterior x-ray images. No reports have used 3-dimensional computed tomography (3D-CT) to analyze both the anterior and posterior elements. The objective of this study was to analyze the morphology and clinical features of HMMS 3 dimensionally.
HMMS was confirmed in 32 (6.6%, 16 males and 16 females) of 483 patients diagnosed with congenital scoliosis at the study institution between 1998 and 2013. The average age at the first visit was 6 years and 3 months. 3D-CT imaging was performed for 30 patients older than 2 years (average age: 9 y and 8 mo) and used to classify cases according to posterior elements.
With regard to the number of hemivertebrae present, 21 patients had 2 hemivertebrae, 7 patients had 3 hemivertebrae, and 2 patients had 4 hemivertebrae. Patients with 2 hemivertebrae predominantly had hemivertebrae in the thoracolumbar spine. Patients were classified into 2 categories: malformation existing at an equal level in anterior and posterior sides (unison HMMS) and malformation existing at nonequal levels (discordant HMMS). Nine patients had unison HMMS and all of them had 2 hemivertebrae (average: 4.6 vertebrae). Twenty-one patients had discordant HMMS, with 12 having 2 hemivertebrae, 7 having 3 hemivertebrae, and 2 having 4 hemivertebrae.
Through 3D-CT analysis, HMMS was categorized as unison or discordant. Discordant HMMS was observed in 21 of 30 (70%) patients and in all patients with >3 hemivertebrae. Diagnosing HMMS, whether unison or discordant, is clinically important and should be done with careful analysis of bone models and/or radiologic images to determine the correct spinal levels.
Level IV-diagnostic study.
这是一项回顾性队列研究。
半椎体节段性移位（HMMS）被定义为一种半椎体畸形，其中脊柱两侧存在2个或更多半椎体，且至少被1个正常椎体分隔。HMMS的报道罕见且基于简单的前路X线图像。尚无研究使用三维计算机断层扫描（3D-CT）分析前后结构。本研究的目的是三维分析HMMS的形态和临床特征。
1998年至2013年期间，在研究机构诊断为先天性脊柱侧凸的483例患者中，32例（6.6%，男性16例，女性16例）确诊为HMMS。首次就诊的平均年龄为6岁3个月。对30例年龄大于2岁（平均年龄：9岁8个月）的患者进行了3D-CT成像，并根据后部结构对病例进行分类。
就半椎体数量而言，21例患者有2个半椎体，7例患者有3个半椎体，2例患者有4个半椎体。有2个半椎体的患者主要在胸腰段有半椎体。患者分为2类：前后侧畸形程度相同（一致型HMMS）和畸形程度不同（不一致型HMMS）。9例患者为一致型HMMS，均有2个半椎体（平均：4.6个椎体）。21例患者为不一致型HMMS，其中12例有2个半椎体，7例有3个半椎体，2例有4个半椎体。
通过3D-CT分析，HMMS分为一致型或不一致型。30例患者中有21例（70%）为不一致型HMMS，所有有>3个半椎体的患者均为不一致型。诊断HMMS，无论是一致型还是不一致型，在临床上都很重要，应通过仔细分析骨模型和/或放射影像来确定正确的脊柱节段。
IV级诊断性研究。
