Sr-HA scaffolds fabricated by SPS technology promote the repair of segmental bone defects.

BACKGROUND: Ideal bone defect repair scaffolds should be biodegradable, biocompatible, bioactive, porous, and provide adequate mechanical support. However, it is challenging to fabricate such an ideal bone repair scaffold. Previously, we showed that 5 wt.% strontium-doped hydroxyapatite (Sr-HA) scaffolds prepared by spark plasma sintering (SPS) technology exhibited good biocompatibility. Moreover, unlike pure hydroxyapatite (HA) scaffolds, HA scaffolds containing strontium (Sr) exhibited superior bioactivity, higher proliferation rate of BMSCs and MG-63 osteoblast cells, as well as enhanced BMSCs differentiation. METHODS: In this study, we prepared pure HA scaffolds and 5 wt.% strontium containing Sr-HA scaffolds by SPS technology without adhesive, ammonium bicarbonate as pore former. Subsequently, scanning electron microscope (SEM) and X-Ray diffraction (XRD) were used to characterize the properties of Sr-HA and HA scaffolds. The ability of the scaffolds to repair bone defects was evaluated using a critical-sized rabbit tibia-bone defect rabbit model. Thirty 3-month-old New Zealand white rabbits were randomly divided into three groups (blank control group, Sr-HA scaffolds implanted group and HA scaffolds implanted group) with 10 rabbits in each group. These rabbits are sacrificed after 8 weeks and 16 weeks of surgery, and the repair effects of each scaffold were evaluated with X-ray, micro-CT, and HE staining. The three-point bending test was employed to assess the mechanical property of repaired bones. RESULTS: XRD pattern indicated that Sr-HA and HA scaffolds possess a similar crystal structure after sintering, and that incorporation of strontium did not form impure phase. SEM showed that the porosity of Sr-HA and HA scaffolds was about 40 %. Universal Testing Machine tests showed that Sr-HA scaffolds had better compressive strength than HA scaffolds. Bone defect was obvious, and the fibrous tissue was formed in the bone defects of rabbits in the blank control group after 8 weeks of surgery. Sr-HA and HA scaffolds enhanced osteointegration of the host bone, and extensive woven bone was formed on the surface of the Sr-HA scaffolds. After 16 weeks, the bone strump became blunt and a small amount of callus was formed in the blank control group. Comparatively, the scaffolds were substantially degraded in the Sr-HA scaffolds implanted group while scaffolds shadows still were observed in the HA implanted group. Bone remodeling and cavity recanalization were completely developed in the Sr-HA scaffolds group. The compressive strength of repaired bone in the Sr-HA scaffolds implantation group was higher than that of HA scaffolds implantation group after 8 weeks and 16 weeks of surgery. CONCLUSIONS: Our results show that the Sr-HA composite scaffolds can effectively repair bone defects and have good biodegradable properties.

Quality of life in adolescent patients with idiopathic scoliosis after brace treatment: A meta-analysis.

BACKGROUND: Whether brace-treated adolescents with idiopathic scoliosis (AIS) have improved quality of life (QoL) is still unknown. Thus, we conducted a meta-analysis to compare the QoL of brace-treated AIS patients with untreated AIS patients. The pain, self-image/appearance, mental health, function/activity, satisfaction with management, total score without satisfaction, and total score of patients were used to measure the QoL after the intervention. METHODS: Multiple electronic databases including PubMed, Web of Science, and Embase were searched for all years up to June 30, 2016. Articles in English that used the Scoliosis Research Society-22 (SRS-22) or a modified version of the SRS-22 questionnaire to evaluate the QoL differences between brace-treated AIS patients and untreated AIS patients were included in the meta-analysis. The Newcastle-Ottawa Scale was used in the quality of literature evaluation. The pooled standardized mean difference (SMD) with its corresponding 95% confidence interval (CI) for each parameter was computed. Egger test and Begg test were used to test for publication bias. RESULTS: The SRS-22 or a modified SRS-22 questionnaire was used to evaluate the QoL after surgery. There was no significant difference in pain (SMD = 0.123, 95% CI: -0.101 to 0.347, P = .282), self-image/appearance (SMD = 0.108, 95% CI: -0.116 to 0.332, P = .334), mental health (SMD = 0.031, 95% CI: -0.130 to 0.201, P = .365), function/activity (SMD = 0.202, 95% CI: -0.022 to 0.425, P = .077), and total score without satisfaction (SMD = 0.123, 95% CI: -0.232 to 0.478, P = .497) between the untreated (observation) and brace-treated AIS patients, whereas a significant difference was observed in satisfaction with management (SMD = 0.393, 95% CI: 0.127-0.659, P = .004) and total score (SMD = 0.312, 95% CI: 0.054-0.571, P = .018) between the 2 groups. CONCLUSION: Our meta-analysis indicated that brace-treated AIS patients had a higher QoL. However, further analysis could not be performed because of insufficient data, such that we were unable to make subgroup analysis of QoL for different types of AIS and the therapeutic methods chosen by brace-treated AIS patients.