To determine whether spinal facet osteoblasts at the curve apex display a different phenotype to osteoblasts from outside the curve in patients with adolescent idiopathic scoliosis (AIS). Intrinsic differences in the phenotype of spinal facet bone tissue and in spinal osteoblasts have been implicated in the pathogenesis of AIS. However, no study has compared the phenotype of facet osteoblasts at the curve apex with the facet osteoblasts from outside the curve in patients with AIS.

Facet bone tissue was collected from three sites, the concave and convex side at the curve apex and from outside the curve from three female patients with AIS (aged 13–16 years). Micro-CT analysis was used to determine the density and trabecular structure. Osteoblasts were then cultured from the sampled bone. Osteoblast phenotype was investigated by assessing cellular proliferation (MTS assay), cellular metabolism (alkaline phosphatase and Seahorse Analyser), bone nodule mineralisation (Alizarin red assay), and the mRNA expression of Wnt signalling genes (quantitative RT-PCR).

Convex bone showed greater bone mineral density and trabecular thickness than did concave bone. The convex side of the curve apex exhibited a significantly higher proliferative and metabolic phenotype and a greater capacity to form mineralised bone nodules than did concave osteoblasts. mRNA expression of SKP2 was significantly greater in both concave and convex osteoblasts than in non-curve osteoblasts. The expression of SFRP1 was significantly downregulated in convex osteoblasts compared with either concave or non-curve.

Intrinsic differences that affect osteoblast function are exhibited by spinal facet osteoblasts at the curve apex in patients with AIS.

Children undergoing posterior spinal fusion (PSF) for neuromuscular and syndromic scoliosis were admitted to the paediatric intensive care (PIC) until about 6 years ago, at which time we created a new unit, a hospital floor-based spinal high-dependency unit-plus (SHDU-plus), in response to frequent bed-shortage cancellations. This study compares postoperative management on PIC with HDU-plus for these non-hospital floor suitable children with syndromic and neuromuscular scoliosis undergoing PSF.

Retrospective review of 100 consecutive children with syndromic and neuromuscular scoliosis undergoing PSF between June 2016 and January 2022. Inclusion criteria were: 1) diagnosis of syndromic or neuromuscular scoliosis, 2) underwent PSF, 3) not suitable for immediate postoperative hospital floor-based care. Exclusion criteria were children with significant cardio-respiratory co-morbidity requiring PIC postoperatively.

55 patients were managed postoperatively on PIC and 45 on SHDU-plus. No significant difference between groups was found with respect to age, weight, ASA grade, preoperative Cobb angles, operative duration, number of levels fused and estimated blood loss. 4 patients in the PIC group and 1 in the SHDU-plus group were readmitted back to PIC or HDU following step-down to the hospital floor. Average length of stay was 2 days on PIC and 1 day on SHDU-plus. Average total length of hospital stay was 16.5 days in the PIC group and 10.5 days in the HDU-plus group. 19 (35%) patients developed complications in the PIC group, compared to 18 (40%) in SHDU-plus. Mean specialist unit charge per day was less on SHDU-plus compared with PIC. There were no bed-shortage cancellations in the SHDU-plus group, compared to 11 in the PIC group.

For children with neuromuscular or syndromic scoliosis undergoing PSF and deemed not suitable for post-operative care on the hospital floor, creation of a SHDU-plus was associated with fewer readmissions back to PIC or HDU, shorter hospital stays, an equivalent complication rate, significant cost-saving and fewer cancellations. Level of Evidence: Therapeutic Level III.

Purpose

To determine if clinical outcomes are correlated with center of rotation (COR) in patients implanted with a viscoelastic total disc replacement (VTDR).