Refracture of cemented vertebrae occurs commonly after vertebroplasty (Vp) for osteoporotic vertebral compression fracture (OVCF). It can result in severe pain or neurological deficit, but no preventive medication is available. Owing to the bone anabolic benefits of teriparatide (TP), this study was aimed to compare the outcomes of cemented vertebrae with tp to those without tp. patients who received Vp for OVCF with at least 1 year follow-up were included. The anterior body height (ABH) and middle body height (MBH) and kyphotic angle (KA) were measured before VP and 1 week and at least 1 year after VP. Refracture was defined as a 15% decrease in ABH or MBH and 8° decrease in KA compared with those at postoperative 1 week. The clinical outcomes were evaluated. 35 VP procedures in 21 patients treated with TP (TP group), and, matched to that, 29 out of 133 patients treated with VP alone (VP group) were included. One year after VP, ABH and MBH were significantly greater, except KA, in the TP group (Vp group vs. tp group: KA − 4.97° ± 12.1 vs. −2.85° ± 12.21°, p = 0.462, ABH 1.56 ± 0.48 cm vs. 1.84 ± 0.56 cm, p = 0.027, MBH 1.49 ± 0.39 cm vs. 1.73 ± 0.41 cm, p = 0.017). The refracture rates of KA, ABH, and MBH were significantly lower in the TP group (VP group vs. TP group: KA 42.11% vs.8.57%, p < 0.001; ABH 76.32% vs. 28.57%, p < 0.0001; MBH 76.32% vs. 28.57%, p < 0.0001). In single-level subgroup comparison, TP was associated with better improvement of pain VAS and better radiological outcomes. TP was associated with higher BHs and fewer refractures than VP alone, with comparable clinical outcomes 1 year after VP. TP may be associated with better improvement of pain VAS in those with single-level VP procedure. Higher BH was due to the better maintenance effect of TP. Refracture of cemented vertebrae after vertebroplasty (VP) occurs frequently in patients with osteoporotic vertebral compression fracture (OVCF). Different studies have reported different incidences of refracture 1-6. Refracture incidence ranged from 0.56% to 76% depending on the definition and follow-up period. Some refractures resulted in severe pain, instability, and even neurological deficits requiring further interventions 2,7-9. Kyphoplasty (KP) with an intravertebral reduction device (IRD) has been reported as a solution to prevent refracture with stronger anterior mechanical support 6. However, after VP, no medical solution exists so far. Teriparatide (TP) is the recombinant human parathyroid hormone (1-34) that increases bone mass 10,11 and decreases the risk of new vertebral fracture in patients with osteoporosis 12,13. Its antiosteoporosis effects depend on the enhancement of osteoblast formation 14 and prevention of osteoblast apoptosis 15. Owing to the anabolic effect, TP had been used to promote the process of bone healing after fracture 11,16-28. For fractures without internal implant fixation, TP was beneficial for nonweight-bearing regions 22,28 but not for weight-bearing regions 25. The role of TP is very controversial for fractures i...

Background: Proper guidance of neuronal axons to their targets is required to assemble neural circuits during the development of the nervous system. However, the mechanism by which the guidance of axonal growth cones is regulated by specific intermediaries activated by receptor signaling pathways to mediate cytoskeleton dynamics is unclear. Vav protein members have been proposed to mediate this process, prompting us to investigate their role in the limb selection of the axon trajectory of spinal lateral motor column (LMC) neurons.Results: We found Vav2 and Vav3 expression in LMC neurons when motor axons grew into the limb. Vav2, but not Vav3, loss-of-function perturbed LMC pathfinding, while Vav2 gain-of-function exhibited the opposite effects, demonstrating that Vav2 plays an important role in motor axon growth. Vav2 knockdown also attenuated the redirectional phenotype of LMC axons induced by Dcc, but not EphA4, in vivo and lateral LMC neurite growth preference to Netrin-1 in vitro. This study showed that Vav2 knockdown and ectopic nonphosphorylable Vav2 mutant expression abolished the Src-induced stronger growth preference of lateral LMC neurites to Netrin-1, suggesting that Vav2 is downstream of Src in this context.Yi-Syue Tsou and Chih-Yang Wang contributed equally to this study.