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A 3-column osteotomy is sometimes challenging in congenital kyphosis (CK) with many anterior unsegmented vertebrae (AUVs). This study compared surgical outcomes of single-level 3-column osteotomy and associated complications in CK with increasing number of AUVs.We retrospectively reviewed 25 consecutive patients with AUVs in CK who underwent surgery at a mean age of 16.2 ± 10.3 years. Patients were stratified into 2 groups according to the number of AUVs: 3 AUVs and ≥4 AUVs. Osteotomy types, surgical outcomes, and related complications were analyzed and compared between groups.The 3 AUVs group comprised 13 patients, and the ≥4 AUVs group comprised 12 patients. Pedicle subtraction osteotomy, grade 4 osteotomy, vertebral column resection, and vertebral column decancellation accounted for 15.4%, 38.5%, 46.1%, and 0% of procedures in the 3 AUVs group and 8.3%, 0%, 83.3%, and 8.3% of procedures in the ≥4 AUVs group. Preoperative focal kyphosis, which was significantly higher in the ≥4 AUVs group (82.9° ± 28° vs. 59.7° ± 9.4°, P = 0.010), was corrected in both groups postoperatively. The ≥4 AUVs group had significantly higher remaining kyphosis (33.6° ± 13.4° vs. 15.1° ± 9.1°, P0.001) with a significantly lower correction rate (61.2% ± 13.6% vs. 75.0% ± 15.6%, P = 0.001). The complication rate, mainly involving vertebral subluxation and proximal junctional kyphosis, was significantly higher in the ≥4 AUVs group than the 3 AUVs group (8/12 vs. 1/13, P = 0.004).Posterior single-level 3-column osteotomy can achieve satisfactory kyphosis correction in CK with 3 AUVs. Decreasing kyphosis correction and increasing surgery-related complications are prone to develop when treating CK with ≥4 AUVs.

Large amounts of organic carbon (OC) and inorganic carbon (IC) are stored in coastal sediments. These carbon compounds play an important role in coping with global climate change. In this study, the surface sediments of four tidal flat sections in northern Jiangsu were analysed for their OC and IC contents, as well as changes in the physical and chemical properties of the sediments (particle size, pH, salinity (SAL), and N, P, and S contents). A partial least squares regression (PLSR) was conducted to explore the factors affecting OC and IC variations. According to the results, the OC and IC contents exhibited increasing trends when moving from the seaward to landward parts of the sections. The OC variations were large and IC variations were small in all four sections and the vegetation coverage contributes to the carbon content of tidal flat sediments. The PLSR analysis indicates that the main factors influencing OC and IC contents in the tidal flat system were particle size (sand, silt, and clay) and N content, while SAL had the least influence on OC and IC contents. The IC and OC contents are positively coupled, which may indicate that the nearshore vegetation has a greater contribution to OC, affects the coastal hydrodynamic conditions, and enhances the retention of IC. Additionally, the transformation of OC to IC also positively contributed to the coupling of their contents.