Adolescent idiopathic scoliosis (AIS) is the most common pediatric spinal deformity. Several AIS susceptibility loci have been identified; however, they could explain only a small proportion of AIS heritability. To identify additional AIS susceptibility loci, we conduct a meta-analysis of the three genome-wide association studies consisting of 79,211 Japanese individuals. We identify 20 loci significantly associated with AIS, including 14 previously not reported loci. These loci explain 4.6% of the phenotypic variance of AIS. We find 21 cis-expression quantitative trait loci-associated genes in seven of the fourteen loci. By a female meta-analysis, we identify additional three significant loci. We also find significant genetic correlations of AIS with body mass index and uric acid. The cell-type specificity analyses show the significant heritability enrichment for AIS in multiple cell-type groups, suggesting the heterogeneity of etiology and pathogenesis of AIS. Our findings provide insights into etiology and pathogenesis of AIS.

A precise comparison of supine and standing whole spine alignment in both the coronal and sagittal planes, including the pelvic parameters, has not been reported. Furthermore, previous studies investigated positional differences in the Cobb angle only in young patients with idiopathic scoliosis. The difference in alignment has never been investigated in a population of patients with adult spinal deformity (ASD). In most cases, ASD patients are aware of the symptoms when standing and tend to stoop with back pain, whereas the symptoms disappear when lying on a bed. Therefore, it is important to elucidate the positional differences in the deformity in older adults. The purposes of this study are to establish a method for comparing whole spine alignment between supine and standing, and to clarify the positional difference of the alignment in the patients with ASD. Twenty-four patients with ASD (mean age: 60.1 years, range 20–80 years; 24 women) were evaluated. A slot-scanning three-dimensional X-ray imager (EOS) was used to assess the whole spine in the standing position. Computed tomography was used to assess the whole spine in the supine position. The computed tomography DICOM dataset of the whole spine in the supine position was transformed to two-dimensional (coronal and sagittal) digital reconstructed radiography images. The digital reconstructed radiography images were input for three-dimensional measurement by the EOS software and compared with the standing whole spine alignment measured by EOS. The mean intraclass correlation coefficients (supine, standing) of intra-rater / inter-rater reliabilities for the measured parameters were 0.981, 0.984 / 0.970, 0.986, respectively. The Cobb and rotation angles of the major curve, mostly the thoracolumbar area, were significantly greater in the standing position than in the supine position. Lumbar lordosis during standing was significantly kyphotic. With respect to the pelvic parameters, the sacral slope was significantly smaller in the standing position than in the supine position. Pelvic tilt and pelvic incidence were significantly greater in the standing position than in the supine position. The lumbar to pelvic parameters and the major curve in standing position significantly deteriorate compared with the supine position in patients with ASD.

Study Design A retrospective case study of the use of posterior lumbar interbody fusion (PLIF) to treat lumbar foraminal stenosis (LFS). Objectives To characterize the features of clinical symptoms, radiographic evaluation, and surgical outcomes of PLIF in LFS. Summary of Background Data There is no gold standard for the surgical treatment of foraminal stenosis, which occurs in 8% to 10% of surgical cases of lumbar degenerative disease. Methods Data from 31 patients (33 segments) who underwent PLIF from 2001 to 2005 at our institution were analyzed. Exclusion criteria included the patients having both LFS and central canal stenosis, plus extraforaminal or intraforaminal disc herniation. There were 22 males and 9 females, with an average age of 61 (31∼78 y). The affected levels were as follows: L3/4 in 1 patient, L4/5 in 4, and L5/S1 in 28. All patients underwent PLIF with the combination of segmental pedicle screws, interbody cages, and autogenous local bone graft. Results The frequencies of Kemp sign (+), intermittent claudication, leg pain in a sitting position, and leg pain at night, were high. Radiographic evaluation showed severe disc degeneration such as loss of disc height, massive osteophyte formation, and transverse offset angles of the nerve root at the corresponding level. Magnetic resonance imaging and 3D-reconstraction computed tomography clearly showed intraforaminal stenosis in sagittal, axial, and coronal planes. The PLIF procedure provided complete root decompression, restoration of disc height, and preservation of lumbar lordosis at final follow-up. The Japanese Orthopedic Association score improved from 17.1 points preoperatively to 24.9 points at final follow-up, and the overall fusion rate was 100%. Conclusion Lumbar foraminal stenosis could be reliably diagnosed by distinctive clinical symptoms, and various radiographic examinations such as plain x-ray, Magnetic resonance imaging, and 3D-reconstraction computed tomography. The PLIF procedure, in combination with segmental pedicle screws, interbody cages, and autogenous local bone graft provides excellent clinical outcomes, and is a rational and useful surgical option for lumbar foraminal stenosis.

In patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification. Data were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated. Women were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL. Thoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.