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Reperfusion injury is an unfortunate consequence of restoring blood flow to tissue after a period of ischemia. This phenomenon can occur in any organ, although it has been best studied in cardiac cells. Based on cardiovascular studies, neuroprotective strategies have been developed. The molecular biology of reperfusion injury remains to be fully elucidated involving several mechanisms, however these mechanisms all converge on a similar final common pathway: blood brain barrier disruption. This results in an inflammatory cascade that ultimately leads to a loss of cerebral autoregulation and clinical worsening. In this article, the authors present an overview of these mechanisms and the current strategies being employed to minimize injury after restoration of blood flow to compromised cerebral territories.

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Two patients presented to outside providers with joint pain. Both had isolated lytic metaphyseal lesions on plain radiographs that were not noted or acted upon. Subsequent radiographs showed large expansile lytic lesions involving the metaphysis and epiphysis extending to the subchondral bone. Both patients were found to have pathology-confirmed giant cell tumors requiring curettage and cementation. Although commonly involving the epiphysis and subchondral bone, giant cell tumors of long bone can present as isolated metaphyseal lesions. Careful examination of radiographs and early detection may make these lesions easier to treat, reducing the risk of recurrence and damage to the articular surface.

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OBJECTIVE: Osteoporosis is increasing in incidence as the ageing population continues to grow. Decreased bone mineral density poses a challenge for the spine surgeon. In patients requiring lumbar interbody fusion, differences in diagnostics and surgical approaches may be warranted. In this systematic review, the authors examine studies performing lumbar interbody fusion in patients with osteopenia or osteoporosis and suggest avenues for future study. METHODS: A systematic literature review of the PubMed and MEDLINE databases was performed for studies published between 1986 and 2020. Studies evaluating diagnostics, surgical approaches, and other technical considerations were included. RESULTS: A total of 13 articles were ultimately selected for qualitative analysis. This includes studies demonstrating the utility of Hounsfield units in diagnosis, a survey of surgical approaches, as well as exploring the use of vertebral augmentation and cortical bone screw trajectory. CONCLUSIONS: This systematic review provides a summary of preliminary findings with respect to the use of Hounsfield units as a diagnostic tool, the benefit or lack thereof with respect to minimally invasive approaches, and the question of whether or not cement augmentation or cortical bone trajectory confers benefit in osteoporotic patients undergoing lumbar interbody fusion. While the findings of these studies are promising, the current state of the literature is limited in scope and, for this reason, definitive conclusions cannot be drawn from these data. The authors highlight gaps in the literature and the need for further exploration and study of lumbar interbody fusion in the osteoporotic spine.

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OBJECTIVE: As the ageing population continues to grow, the incidence of osteoporosis continues to rise. Patients with osteoporosis are often managed pharmacologically. It is unclear the impact of these medications on osteoporotic patients requiring lumbar interbody fusion, and whether differences exist with respect to patient outcomes among the different medication classes that are often employed. In this systematic review, the authors examine studies evaluating the impact of pharmacologic therapy on osteoporotic patients undergoing lumbar interbody fusion. METHODS: Using PubMed and MEDLINE databases, the authors conducted a systematic literature review for studies published between 1986 and 2020 following PRISMA guidelines. RESULTS: A total of 12 articles were ultimately selected. Studies assessing bisphosphonate usage, parathyroid hormone analogues, vitamin D, or combination therapies and their impact on lumbar interbody fusion were included. CONCLUSIONS: The evidence regarding bisphosphonate therapy and improved fusion rates with reduced incidence of complications is inconsistent. While some studies suggest bisphosphonates to confer added benefit, other studies suggest no such improvements despite reduction in bone turnover biomarkers. Teriparatide, on the other hand, consistently demonstrated improved fusion rates and may reduce screw loosening events. In comparison studies against bisphosphonates, teriparatide demonstrates greater potential. A single study reported vitamin D3 to increase fusion rates, although more studies are needed to validate this finding. It is important to note that these benefits are only demonstrated in single-level fusion, with multi-level fusions not being significantly enhanced by teriparatide therapy. Combination therapy with denosumab further augment fusion rates. Further prospective randomized controlled trials are necessary before standardized recommendations regarding pharmacological intervention in patients undergoing LIF can be made.

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Glioma continues to be a challenging disease process, making up the most common tumor type within the pediatric population. While low-grade gliomas are typically amenable to surgical resection, higher grade gliomas often require additional radiotherapy in conjunction with adjuvant chemotherapy. Molecular profiling of these lesions has led to the development of various pharmacologic and immunologic agents, although these modalities are not without great systemic toxicity. In addition, the molecular biology of adult glioma and pediatric glioma has been shown to differ substantially, making the application of current chemotherapies dubious in children and adolescents. For this reason, therapies with high tumor specificity based on pediatric tumor cell biology that spare healthy tissue are needed. Oncolytic virotherapy serves to fill this niche, as evidenced by renewed interest in this domain of cancer therapy. Initially discovered by chance in the early 20th century, virotherapy has emerged as a viable treatment option. With promising results based on preclinical studies, the authors review several oncolytic viruses, with a focus on molecular mechanism and efficacy of these viruses in tumor cell lines and murine models. In addition, current phase I clinical trials evaluating oncolytic virotherapy in the treatment of pediatric glioma are summarized.

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