OBJECTIVE: To evaluate different patterns of coronal deformity secondary to ankylosing spondylitis (AS), to propose relevant treatment strategies, and to assess efficacy of asymmetrical pedicle subtraction osteotomy (APSO).
METHODS: Coronal deformity was defined as coronal Cobb angle over 20º or coronal balance distance (CBD) more than 3 cm. 65 consecutive AS patients with concomitant coronal and sagittal deformity who underwent PSO were included. The average follow-up time was 40.4 months. Radiographic evaluation included coronal Cobb angle and CBD. Furthermore, sagittal parameters were used to assess magnitude and maintenance of kyphosis correction.
RESULTS: Based on curve characteristics, coronal deformity caused by AS included four different radiologic patterns: Pattern I: lumbar scoliosis; Pattern II: C-shaped thoracolumbar curve; Pattern III: trunk shift without major curve; Pattern IV: proximal thoracic scoliosis. APSO was performed for patients in Pattern I to III while conventional PSO was applied for patients in Pattern IV. Significant improvement in all the sagittal parameters were noted in 65 patients without obvious correction loss at the last follow-up. Besides, significant and sustained correction of coronal mal-alignment was identified in 59 APSO-treated patients. Rod fracture occurred in four cases and revision surgery was performed for one case.
CONCLUSIONS: According to radiologic manifestations, coronal deformity caused by AS could be categorized into four patterns. APSO proved to be a feasible and effective procedure for correction of Pattern I to III patients. Coronal deformity pattern, apex location, sagittal profile of lumbar spine and preoperative hip function should be considered for osteotomy level selection in APSO.

UNASSIGNED: To investigate the relationship between sagittal alignment and coronal deformity in patients with adolescent idiopathic scoliosis (AIS) through analysis of the spinal imaging data.
UNASSIGNED: Four hundred and fifty-four AIS patients who underwent anteroposterior and lateral radiography of the while spine were enrolled, and the spinal parameters of Cobb angle, cervical lordosis, C1-C2 angle, T1 slope, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt (PT), pelvic incidence (PI), cervical sagittal vertical axis (SVA), and spinal SVA were analyzed.
UNASSIGNED: The patients were divided into two groups according to the size of the Cobb angle: group A (Cobb angle ≤45°, n=414) and group B (Cobb angle >45°, n=40). In group A, the Cobb angle was in a medium negative correlation with the cervical lordosis angle (r=-0.637, P<0.001), a weak positive correlation (|r|<0.3, P<0.05) with C1-C2 angle, T1 slope and thoracic kyphosis. In group B, the Cobb angle was in a mild positive correlation (P<0.05) with PT (r=0.398) and PI (r=0.360). The cervical lordosis angle was significantly (P<0.05) different between male and female patients in both groups. In Group A, the cervical lordosis angle was in a significantly (P<0.01) positive correlation with the T1 slope (r=0.586), thoracic kyphosis (r=0.490), and sagittal vertical axis (r=0.135), and a significantly (P<0.01) negative correlation with cervical sagittal vertical axis (r=-0.128) and C1-C2 angle (r=-0.155). In group B, the cervical lordosis angle was in a significantly (P<0.05) positive correlation with T1 slope (r=0.661), thoracic kyphosis (r=0.608), lumbar lordosis (r=0.425), sacral slope (r=0.434), and sagittal vertical axis (r=0.335).
UNASSIGNED: In AIS patients with the Cobb angle ≤45º, a significant negative correlation exists between the cervical lordosis and the Cobb angle. The sagittal morphology of the cervical spine in AIS patients is affected by the spinal coronal deformity, which plays an important role in the treatment of AIS.

OBJECTIVE: To characterize the sagittal alignment of each Lenke type and investigate the relationship between coronal and sagittal deformities in adolescent idiopathic scoliotic (AIS) patients.
METHODS: A cohort of 184 subjects with AIS was retrospectively recruited. Radiographic data were measured and collected, including the Lenke types, Cobb angles of structural curves, and sagittal spino-pelvic parameters. Subjects were grouped according to their genders, Lenke curve types, lumbar modifiers and the amount of coronal structural curves. The sagittal alignment was then compared between the different groups, and correlation analysis was also taken between coronal and sagittal parameters. Besides, each subject\'s Roussouly type was decided and its distribution was compared among different Lenke types.
RESULTS: The cohort included 59 males and 125 females, averagely aged at 15.5 ± 3.3 years old. Most sagittal parameters except thoracic kyphosis (TK) and pelvic tilt (PT) were similar among different Lenke types, while all the sagittal parameters were similar between males and females. The groups with different lumbar modifiers had similar sagittal parameters except TK, which was also true for the groups with different amounts of coronal curves. 42.4 % of the cohort belonged to Roussouly type 3, and the distribution of Roussouly types was comparable among all Lenke types. All sagittal parameters except C7 translation ratio were significantly different among Roussouly types (P < 0.05). Correlation analysis showed that main thoracic (MT) was negatively correlated with lumbar lordosis (LL, r = -0.324), sacral slope (r = -0.321) and spino-sacral angle (r = -0.363). Partial correlation analysis found that thoracolumbar/lumbar was negatively correlated with TK (r = -0.464) and LL (r = -0.422) when MT was controlled.
CONCLUSIONS: The influence of coronal deformity on sagittal parameters was limited and mainly reflected in the deviation of TK. Most coronal and sagittal parameters were not significantly correlated, and the coronal deformity types did not change the global sagittal postural patterns.