Etiology of adolescent idiopathic scoliosis (AIS), a complicated three-dimensional spinal deformity with early-onset, receives continuous attention but remains unclear. To gain an insight into AIS pathogenesis, this review searched PubMed database up to June 2019, using key words or medical subject headings terms including “adolescent idiopathic scoliosis,” “scoliosis,” “pathogenesis,” “etiology,” “genetics,” “mesenchymal stem cells,” and their combinations, summarized existing literatures and categorized the theories or hypothesis into nine aspects. These aspects include bone marrow mesenchymal stem cell studies, genetic studies, tissue analysis, spine biomechanics measurements, neurologic analysis, hormone studies, biochemical analysis, environmental factor analysis, and lifestyle explorations. These categories could be a guidance for further etiology or treatment researches to gain inspiration.

Adolescent idiopathic scoliosis (AIS) is a complex, three-dimensional deformity of the spine that commonly occurs in pubescent girls. Decreased osteogenic differentiation and aberrant melatonin signalling have been demonstrated in mesenchymal stem cells (MSCs) from AIS patients and are implicated in the pathogenesis of AIS. However, the molecular mechanisms underlying these abnormal cellular features remain largely unknown. Our previous work comparing gene expression profiles between MSCs from AIS patients and healthy controls identified 1027 differentially expressed genes. In the present study, we focused on one of the most downregulated genes, SPRY4, in the MAPK signalling pathway and examined its role in osteogenic differentiation. We found that SPRY4 is markedly downregulated in AIS MSCs. Knockdown of SPRY4 impaired differentiation of healthy MSCs to osteoblasts, while SPRY4 overexpression in AIS MSCs enhanced osteogenic differentiation. Furthermore, melatonin treatment boosted osteogenic differentiation, whereas SPRY4 ablation ablated the promotional effects of melatonin. Moreover, SPRY4 was upregulated by melatonin exposure and contributed to osteogenic differentiation and melatonin response in a MEK-ERK1/2 dependent manner. Thus, loss of SPRY4 in bone marrow derived-MSCs results in reduced osteogenic differentiation, and these defects are further aggravated under the influence of melatonin. Our findings provide new insights for understanding the role of melatonin in AIS aetiology and highlight the importance of MSCs in AIS pathogenesis.

Background: Although intravenous tranexamic acid administration (ivTXA) has prevailed in clinical antifibrinolytic treatment, whether it increases thromboembolic risks has remained controversial. As a potent alternative to ivTXA, topical use of TXA (tTXA) has been successfully applied to attenuate blood loss in various surgical fields while minimizing systemic exposure to TXA. This meta-analysis was conducted to gather scientific evidence for tTXA efficacy on reducing postoperative drainage, blood loss, and the length of hospital stay in spine surgeries. Objectives: To examine whether topical use of TXA (tTXA) reduces postoperative drainage output and duration, hidden blood loss, hemoglobin level drop, hospital stay, and adverse event rate, we reviewed both randomized and non-randomized controlled trials that assessed the aforementioned efficacies of tTXA compared with placebo in patients undergoing cervical, thoracic, or lumbar spinal surgeries. Methods: An exhaustive literature search was conducted in MEDLINE and EMBASE databases from January 2000 through March 2020. Measurable outcomes were pooled using Review Manager (RevMan) version 5.0 in a meta-analysis. Results: Significantly reduced postoperative drainage output (weighted mean difference [WMD]= − 160.62 ml, 95% confidence interval (95% CI) [− 203.41, − 117.83]; p < .00001) and duration (WMD= − 0.75 days, 95% CI [− 1.09, − 0.40]; p < .0001), perioperative hidden blood loss (WMD= − 91.18ml, 95% CI [− 121.42, − 60.94]; p < .00001), and length of hospital stay (WMD= − 1.32 days, 95% CI [− 1.90, − 0.74]; p < .00001) were observed in tTXA group. Pooled effect for Hb level drop with tTXA vs placebo crossed the equivalent line by a mere 0.05 g/dL, with the predominant distribution of 95% confidence interval (CI) favoring tTXA use. Conclusions: With the most comprehensive literature inclusion up to the present, this meta-analysis suggests that tTXA use in spinal surgeries significantly reduces postoperative drainage, hidden blood loss, and hospital stay duration. The pooled effect also suggests that tTXA appears more effective than placebo in preserving postoperative Hb level, which needs further validation by future studies.

Objectives To evaluate the morphine-sparing effects of the sequential treatment versus placebo in subjects undergoing total knee arthroplasty (TKA), the effects on pain relief, inflammation control and functional rehabilitation after TKA and safety. Design Double-blind, pragmatic, randomised, placebo-controlled trial. Setting Four tertiary hospitals in China. Participants 246 consecutive patients who underwent elective unilateral TKA because of osteoarthritis (OA). Interventions Patients were randomised 1:1 to the parecoxib/celecoxib group or the control group. The patients in the parecoxib/celecoxib group were supplied sequential treatment with intravenous parecoxib 40 mg (every 12 hours) for the first 3 days after surgery, followed by oral celecoxib 200 mg (every 12 hours) for up to 6 weeks. The patients in the control group were supplied with the corresponding placebo under the same instructions. Primary and secondary outcome measures The primary endpoint was the cumulative opioid consumption at 2 weeks post operation (intention-to-treat analysis). Secondary endpoints included the Knee Society Score, patient-reported outcomes and the cumulative opioid consumption. Results The cumulative opioid consumption at 2 weeks was significantly smaller in the parecoxib/celecoxib group than in the control group (median difference, 57.31 (95% CI 34.66 to 110.33)). The parecoxib/celecoxib group achieving superior Knee Society Scores and EQ-5D scores and greater Visual Analogue Scale score reduction during 6 weeks. Interleukin 6, erythrocyte sedation rate and C-reactive protein levels were reduced at 72 hours, 2 weeks and 4 weeks and prostaglandin E2 levels were reduced at 48 hours and 72 hours in the parecoxib/celecoxib group compared with the placebo group. The occurrence of adverse events (AEs) was significantly lower in the parecoxib/celecoxib group. Conclusions The sequential intravenous parecoxib followed by oral celecoxib regimen reduces morphine consumption, achieves better pain control and functional recovery and leads to less AEs than placebo after TKA for OA. Trial registration number ClinicalTrials.gov (ID: NCT02198924).