Comparing the osteogenesis outcomes of different lumbar interbody fusions (A/O/X/T/PLIF) by evaluating their mechano-driven fusion processes.

BACKGROUND: In lumbar interbody fusion (LIF), achieving proper fusion status requires osteogenesis to occur in the disc space. Current LIF techniques, including anterior, oblique, lateral, transforaminal, and posterior LIF (A/O/X/T/PLIF), may result in varying osteogenesis outcomes due to differences in biomechanical characteristics. METHODS: A mechano-regulation algorithm was developed to predict the fusion processes of A/O/X/T/PLIF based on finite element modeling and iterative evaluations of the mechanobiological activities of mesenchymal stem cells (MSCs) and their differentiated cells (osteoblasts, chondrocytes, and fibroblasts). Fusion occurred in the grafting region, and each differentiated cell type generated the corresponding tissue proportional to its concentration. The corresponding osteogenesis volume was calculated by multiplying the osteoblast concentration by the grafting volume. RESULTS: TLIF and ALIF achieved markedly greater osteogenesis volumes than did PLIF and O/XLIF (5.46, 5.12, 4.26, and 3.15 cm3, respectively). Grafting volume and cage size were the main factors influencing the osteogenesis outcome in patients treated with LIF. A large grafting volume allowed more osteoblasts (bone tissues) to be accommodated in the disc space. A small cage size reduced the cage/endplate ratio and therefore decreased the stiffness of the LIF. This led to a larger osteogenesis region to promote osteoblastic differentiation of MSCs and osteoblast proliferation (bone regeneration), which subsequently increased the bone fraction in the grafting space. CONCLUSION: TLIF and ALIF produced more favorable biomechanical environments for osteogenesis than did PLIF and O/XLIF. A small cage and a large grafting volume improve osteogenesis by facilitating osteogenesis-related cell activities driven by mechanical forces.

COVID-19 vaccine acceptability among healthcare workers in Yemen

Background:Acceptability of COVID-19 vaccine by healthcare workers (HCWs) can affect its acceptability by the general population.Aim:To assess COVD-19 vaccine acceptability among HCWs in Sana’a, Yemen.Methods:We conducted a multicentre cross-sectional study among 391 HCWs in Sana’a, Yemen, from January to March 2022. We used a self-administered questionnaire to collect data on the demographics, profession, academic qualifications, and experience of HCWs, as well as their COVID-19 vaccine acceptability or hesitancy. We used univariate and multivariable logistic regression to analyse the association between the independent variables and vaccine hesitancy (P < 0.05).Results:Of the 391 HCWs, only 194 (49.6%) were willing to accept the COVID-19 vaccine. The most frequent reasons for vaccine hesitancy were fear of adverse reactions (77.7%), concerns about unknown effects of the vaccine in the future (73.1%), and uncertainty about the safety of new vaccines (69.5%). Female gender and working in the public sector were independent predictors of vaccine hesitancy among the HCWs.Conclusion:Nearly half of the HCWs in Sana’a, Yemen, were willing to accept the COVID-19 vaccine. Female gender and working in the public health sector were independent predictors of vaccine hesitancy. We recommend further studies to compare COVID-19 acceptability among HCWs in the public and private sectors in Yemen.