Magnesium metal and its alloys have been proposed as a novel class of bone implant biomaterials because of their biodegradability and mechanical properties. The purpose of this study was to determine whether magnesium ions, which are released abundantly from alloys, affect proliferation and differentiation of human bone marrow-derived stromal cells (hBMSCs). High levels of magnesium ions did not induce cytotoxicity in hBMSCs, but treatment with 2.5–10 mm magnesium ions for 48–72 h significantly increased hBMSC proliferation. The expression of integrins α2 and α3, but not β1, was upregulated compared with the control and shifted from α3 to α2 in hBMSCs treated with magnesium ions. Knockdown of integrins α2 and/or α3 significantly reduced magnesium-induced proliferation of hBMSCs. Magnesium exposure profoundly enhanced alkaline phosphatase (ALP) gene expression and activity even at a relatively low magnesium concentration (2.5 mm). Exposure to magnesium ions facilitated hBMSC proliferation via integrin α2 and α3 expression and partly promoted differentiation into osteoblasts via the alteration of ALP expression and activity. Accordingly, magnesium could be a useful biomaterial for orthopaedic applications such as bone implant biomaterials for repair and regeneration of bone defects in orthopaedic and dental fields. Copyright © 2014 John Wiley & Sons, Ltd.

The contribution of preoperative embolization in reducing intraoperative blood loss and its clinical importance are unclear. So, we aimed to compare the perioperative clinical outcomes based on whether preoperative embolization was performed and assess the role and safety of preoperative embolization in metastatic spinal cord compression (MSCC) patients. We enrolled 52 patients (men, 37; women, 15) who underwent palliative decompression for MSCC. Demographic data, neurologic status, surgery-related data (operation time, estimated blood loss, and transfusion), complications, and survival time were recorded. Patients were categorized based on whether they received preoperative embolization: groups E (embolization) (n = 18) and NE (non-embolization) (n = 34) and the clinical parameters were compared. Subgroup analysis was performed specifically for cases of hypervascular tumors (23/52, 44%). The transfusion degree was greater in the NE group (4.6 pints) than in the E group (2.5 pints, P = 0.025); the other parameters did not differ between the groups. However, massive bleeding (>2000 mL) was more frequent in the NE group (10/34) than in the E group (0/18, P = 0.010). Subgroup analysis indicated that intraoperative blood loss was greater in the NE group (1988 mL) than in the E group (1095 mL, P = 0.042) in hypervascular tumor patients. Although massive bleeding was more frequent among hypervascular tumor patients, 3 patients with non-hypervascularized tumors also exhibited massive bleeding (P = 0.087). Intraoperative blood loss and perioperative transfusion can be reduced by preoperative embolization in MSCC patients. Neurologic recovery, operation time, and complications did not differ according to the application of embolization. As preoperative embolization is relatively safe and effective for controlling intraoperative bleeding without any neurologic deterioration, it is highly recommended for hypervascular tumors. Moreover, it may also be effective for non-hypervascular tumors as massive bleeding may be noted in some cases.

Background: Although several studies on the Mg-Zn-Ca system have focused on alloy compositions that are restricted to solid solutions, the influence of the solid solution component of Ca on Mg-Zn alloys is unknown. Therefore, to broaden its utility in orthopedic applications, studies on the influence of the addition of Ca on the microstructural, mechanical, and corrosion properties of Mg-Zn alloys should be conducted. In this study, an in-depth investigation of the effect of Ca on the mechanical and bio-corrosion characteristics of the Mg-Zn alloy was performed for the optimization of a clinically approved Mg alloy system comprising Ca and Zn. Methods: The Mg alloy was fabricated by gravitational melting of high purity Mg, Ca, and Zn metal grains under an Ar gas environment. The surface and cross-section were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to analyze their crystallographic structures. Electrochemical and immersion tests in Hank’s balanced salt solution were used to analyze their corrosion resistance. Tensile testing was performed with universal testing equipment to investigate the impact of Ca addition. The examination of cytotoxicity for biometric determination was in line with the ISO10993 standard. Results: In this study, the 0.1% Ca alloy had significantly retarded grain growth due to the formation of the tiny and well-dispersed Ca ₂ Mg ₆ Zn ₃ phase. In addition, the yield strength and elongation of the 0.1% Ca alloy were more than 50% greater than the 2% Zn alloy. The limited cell viability of the 0.3% Ca alloy could be attributed to its high corrosion rate, whereas the 0.1% Ca alloy demonstrated cell viability of greater than 80% during the entire experimental period. Conclusion: The effect of the addition of Ca on the microstructure, mechanical, and corrosion characteristics of Mg-Zn alloys was analyzed in this work. The findings imply that the Mg-Zn alloy system could be optimized by adding a small amount of Ca, improving mechanical properties while maintaining corrosion rate, thus opening the door to a wide range of applications in orthopedic surgery.

Degenerative cervical myelopathy (DCM) is a leading cause of disability, and its surgical management is crucial for improving patient neurological outcomes. Given the varied presentations and severities of DCM, treatment options are diverse. Surgeons often face challenges in selecting the most appropriate surgical approach because there is no universally correct answer. This narrative review aimed to aid the decision-making process in treating DCM by presenting a structured treatment algorithm. The authors categorized surgical scenarios based on an algorithm, outlining suitable treatment methods for each case. Four primary scenarios were identified based on the number of levels requiring surgery and K-line status: (1) K-line (+) and ≤3 levels, (2) K-line (+) and ≥3 levels, (3) K-line (−) and ≤3 levels, and (4) K-line (−) and ≥3 levels. This categorization aids in determining the appropriateness of anterior or posterior approaches and the necessity for fusion, considering the surgical level and K-line status. The complexity of surgical situations and diversity of treatment methods for DCM can be effectively managed using an algorithmic approach. Furthermore, surgical techniques that minimize the stages and address challenging conditions could enhance treatment outcomes in DCM.

Occasionally, ossification of the posterior longitudinal ligament (OPLL) causes cord compression, resulting in cervical myelopathy. OPLL differs from other causes of cervical spondylotic myelopathy in several ways, and the surgical strategy should be chosen with OPLL’s characteristics in mind. Although both the anterior and posterior approaches are effective surgical methods for the treatment of OPLL cervical myelopathy, they each have their own set of benefits and drawbacks. Anterior decompression and fusion (ADF) may improve neurological recovery, restore lordosis, and prevent OPLL mass progression. The benefits can be seen in patients with a high canal occupying ratio or kyphotic alignment. We discussed the benefits, limitations, indications, and surgical techniques of ADF for the treatment of OPLL-induced cervical myelopathy in this narrative.