Limb (digit) replantation is the primary treatment in salvage of severed traumatic limbs (digits). It is vital to improve the success rate of limb (digit) salvage and the function recovery. Once a human limb (digit) is separated from the body, blood circulation stops and normal physiological metabolism are disrupted, hence result in a series of physiological and pathological changes such as cell degeneration and tissue necrosis, which greatly affect the therapeutic effect of limb (digit) replantation. Therefore, how to scientifically minimise the metabolism of tissues in a severed limb (digit) and mitigate the subsequent ischaemia-reperfusion injury to improve the success rate of limb (digit) replantation is a hot issue in the field of limb (digit) replantation. In this article, a review of current status and progress of existing limb (digit) preservation methods are presented. Through an extensive search and analysis of literatures, the advantages and disadvantages of current limb (digit) preservation methods are summarised in the hope that it will provide a reference for clinical preservation of severed limbs (digit) .

Objective:To compare the mechanical properties between our self-designed axially controlled compression spinal rod (ACCSR) and conventional spinal rod (CSR) for lumbar spondylolysis (LS).Methods:This study selected 36 ACCSRs (the ACCSR group) and 36 CSRs (the CSR group), both of which were in a diameter of 6.0 mm and manufactured in the same batch. They were subjected respectively to biomechanical tests of spinal rod and pedicle screw-rod internal fixation system. In spinal rod tests: the stiffness and yield load of the spinal rods were calculated using four-point bending tests ( n=7) and comparisons were made between the 2 groups; spinal rod fatigue tests ( n=8) recorded the successful compression loads after 2.5 million cycles of loading and compared them with the maximum force at the isthmus of a normal adult's unilateral lumbar spine (198.72 N). In tests of the pedicle screw-rod internal fixation system, the axial compression tests ( n=7) measured the axial gripping capacity, the axial torsion tests ( n=7) the torsional gripping capacity, and the lateral compression tests ( n=7) the stiffness and yield load of pedicle screws in the 2 groups respectively. Results:The stiffness [(1,543.37±61.41) N/mm] and yield load [1,338.57 (1,282.00, 1,353.80) N] of ACCSR group were significantly smaller than those of CSR group [(3,797.63±156.15) N/mm and 4,059.95 (3,813.80, 4,090.89) N] ( P<0.05). The spinal rod fatigue tests showed that the respective loads of CSR and ACCSR passing the 2.5 million fatigue tests were 640.00 N and 320.00 N, both larger than the maximum force at the unilateral lumbar isthmus of a normal adult (198.72 N). There were no significant differences between the ACCSR group and the CSR group in the axial gripping capacity and torsional gripping capacity, as well as in stiffness and yield load of screws between the 2 groups ( P>0.05). Conclusions:In fixation of LS, although the yield load, stiffness and fatigue resistance of ACCSR are inferior to those of CSR, the biomechanical properties of the two sets of pedicle screw-rod internal fixation system are comparable. The fatigue resistance of ACCSR can meet the stress requirements of the normal human isthmus.

Tissue engineering bone technology, grounded in seed cells, cytokines, and scaffold supports, provides an effective solution for addressing extensive bone defects, demonstrating significant potentials in the field of bone repair. However, this technology still faces numerous challenges. Focusing on vascularization in engineered bones, this article reviews various methods to enhance vascularization within tissue-engineered bones, including multicellular co-culture, application of angiogenic factors, advanced 3D printing, and aid of surgical interventions. This article also analyses the latest research developments and the limitations of the methods, and speculates future research directions for tissue engineered bone.