Yan Jin Lee

Study Design: Retrospective cohort study. Objective: To perform an exploratory comparison of clinical, radiologic, and perioperative outcomes of transforaminal lumbar interbody fusion (TLIF) using two recombinant human bone morphogenetic protein-2 (rhBMP-2) formulations, Infuse® (Medtronic, Minneapolis) and Novosis® (CG Bio, Seoul, South Korea). Summary of Background Data: Bone morphogenetic protein-2 has become a common osteoinductive agent in lumbar fusion. Infuse®, derived from Chinese Hamster Ovary cells, is effective but associated with inflammatory complications. Novosis®, an Escherichia coli –derived rhBMP-2 embedded in a hydroxyapatite/β-tricalcium phosphate carrier, potentially allows sustained protein release and lower local inflammatory response. Comparative data between these two agents in TLIF remains limited. Materials and Methods: We retrospectively reviewed patients who underwent 1- to 3-level TLIF for degenerative lumbar disorders using either Infuse® or Novosis® between 2018 and 2023. Demographics, perioperative parameters, and complications were extracted from medical records. Radiologic fusion was assessed using a six-zone scoring system at 3, 6, and 12 months. Clinical outcomes included visual analogue scale (VAS) for pain, Oswestry Disability Index (ODI), and SF-36 physical (PCS) and mental (MCS) scores. Groups were compared using t -tests or χ ² analysis with significance at P vs . 10.5% at 3 mo; P vs . 5.1±1.9 d; P =0.011). At 12 months, fusion rates were comparable (100% vs . 93%; P =0.162). ODI improvement favored Novosis® ( P =0.007), while SF-36 MCS improvement favored Infuse® ( P <0.001). Subgroup analysis for 1- and 2-level TLIFs did not show any significant difference in the measured outcomes. No ectopic bone formation or malignancy was observed. Conclusion: Novosis® showed earlier radiographic consolidation and a shorter drain duration, findings that may reflect carrier-specific properties, whereas Infuse® demonstrated greater mental health improvement. Overall, fusion and clinical outcomes were satisfactory with each formulation, although these observations remain exploratory and require validation in larger, prospective studies. Level of Evidence: Level III.

A mechanochemical effect is investigated to reduce diamond tool wear by means of applying a surfactant to low-carbon magnetic iron during diamond turning. Orthogonal microcutting demonstrates the manifestation of the mechanochemical effect through the reduction of cutting forces by 30%, which supports the notion of lower cutting temperatures for reduced tribo-chemical wear. This is affirmed by the reduction in tool flank wear by up to 56% with the mechanochemical effect during diamond turning. While wear suppression increases by 9.4–16.15% with feeds from 5–20 μm/rev, it is not proportional to the reduction in cutting forces (31–39.8%), which suggests that the reduction in cutting energy does not directly correspond with the reduction in heat energy to sustain tribo-chemical tool wear. The strain localization during chip formation is proposed to serve as a heat source that hinders the wear mitigation efficiency. Finite element simulations demonstrate the heat generation during strain localization under the mechanochemical effect, which counteracts the reduced heat conversion from the plastic deformation and the transfer from tool–chip contact. Hence, this paper demonstrates the effectiveness of the mechanochemical method and its ability to reduce tool wear, but also establishes its limitations due to its inherent nature for heat generation.