Search

Systemic Intermittent Hypoxic Therapy (IHT) relies on the adaptive response to hypoxic stress. We investigated allogenic bone-graft resorption in the lumbar spine in 48 mice. The mice were exposed to IHT for 1 week before surgery or 1 week after surgery and compared with controls after 1 and 4 weeks. Complete graft resorption was observed in 33–36% of the animals in the control group, but none in the preoperative IHT group. Increased bone-graft volume was demonstrated by micro-computed tomography in the preoperative IHT group after 1 week (p = 0.03) while a non-significant difference was observed after 4 weeks (p = 0.12). There were no significant differences in the postoperative IHT group. Increased concentration of immune cells was localized in the graft area, and more positive tartrate-resistant acid phosphatase (TRAP) staining was found in controls compared with IHT allogenic bone grafts. Systemic IHT resulted in a significant increase of the major osteoclast inhibitor osteoprotegerin as well as osteogenic and angiogenic regulators Tgfbr3, Fst3l, Wisp1, and Vegfd. Inflammatory cytokines and receptor activator of nuclear factor kappa-B ligand (RANKL) stimulators IL-6, IL-17a, IL-17f, and IL-23r increased after 1 and 4 weeks, and serum RANKL expression remained constant while Ccl3 and Ccl5 decreased. We conclude that the adaptive response to IHT activates numerous pathways leading to inhibition of osteoclastic activity and inhibition of allogenic bone-graft resorption. [ABSTRACT FROM AUTHOR]

Introduction: Patients undergoing scoliosis management are exposed to repeated radiological imaging. Previous studies have shown an increase in incidence of cancer among these patients. The primary aim of this study was to evaluate the radiographic examinations and cumulative radiation dose to which scoliotic patients are exposed. A secondary aim was to compare in-house algorithms of scoliosis management and radiographic follow-up to international spine centres and current consensus literature., Materials and Methods: A single-centre retrospective review evaluating type and frequency of radiographic imaging and total cumulative radiation exposure to patients treated for scoliosis. Inclusions: patients followed for idiopathic scoliosis in the years 2013-2016. A survey asking for information on management and radiological follow-up algorithms was sent to a number of international spine centres for comparison with the in-house algorithm., Results: Patients who underwent surgery received an approximately ten-fold higher median cumulative radiation dose than those treated conservatively. A variety of radiological follow-up algorithms among eight spine centres was observed., Conclusions: Cumulative radiation dose during scoliosis treatment varies substantially depending on radiographic follow-up protocol, intraoperative and ancillary imaging. By using low-dose X-ray systems in combination with a low-dose protocol for intraoperative navigation, it is possible to keep exposure to patients at a minimum while still providing optimal care., Funding: none., Trial Registration: not relevant., (Articles published in the DMJ are “open access”. This means that the articles are distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits any non-commercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.)