Biological and Clinical Aspects of Metastatic Spinal Tumors.

Spine metastases are a common life-threatening complication of advanced-stage malignancies and often result in poor prognosis. Symptomatic spine metastases develop in the course of about 10% of malignant neoplasms. Therefore, it is essential for contemporary medicine to understand metastatic processes in order to find appropriate, targeted therapeutic options. Thanks to continuous research, there appears more and more detailed knowledge about cancer and metastasis, but these transformations are extremely complicated, e.g., due to the complexity of reactions, the variety of places where they occur, or the participation of both tumor cells and host cells in these transitions. The right target points in tumor metastasis mechanisms are still being researched; that will help us in the proper diagnosis as well as in finding the right treatment. In this literature review, we described the current knowledge about the molecular pathways and biomarkers engaged in metastatic processes involving the spine. We also presented a current bone-targeted treatment for spine metastases and the emerging therapies targeting the discussed molecular mechanisms.

The Incidence, Localization and Clinical Relevance of Arterial Fenestrations and Their Association to Brain Aneurysms: A Case-Control Study Based on the STROBE Guidelines.

Background: Fenestrations are rare, but well-known, vascular variations of the cerebral arteries. They are mostly incidental, asymptomatic angiographic findings and might precipitate vascular lesions such as AVM, aneurysmal dilatation, or even ischemic symptoms. However, association between arterial fenestration and brain aneurysms has not been clearly established. Objective: To evaluate whether incidence of arterial fenestrations are associated with brain aneurysm development and investigate the prevalence and most-common localizations of arterial fenestrations of the human brain. Design: Case−control study. Setting: All patients examined by CT angiography in University Hospital No. 4 in Lublin from 2009 to 2019. Patients: Each patient showing at least one cerebral aneurysm was included in the case group and each patient without cerebral aneurysm on CT angiography was included in the control group. Measurements: CT angiography examinations were conducted using the standard protocol used in the 1st Department of Radiology, Medical University of Lublin, Poland. The database and statistical research were conducted by use of the Statistica software (ver. 13.3, Tibco Software Inc., Palo Alto, CA, USA). Results: A total of 6545 CTA examinations were included in the study. Most of the aneurysms were located on the MCA: 629 (38.59%), ICA: 466 (28.59%) and AComA: 192 (11.78%). Cerebral arterial fenestration showed a non-statistically significant elevated risk for brain aneurysms in the entire study population (OR: 1.157; 95% CI: 0.826−1.621; p = 0.39). Among 6545 cranial CTA examinations, cerebral vessel fenestration was found in 49 of them, which constituted 0.75%. The most common vascular fenestrations were those located in the ACA (30.61%), BA (30.61%) and AComA (22.45%), while other fenestrations occurred infrequently. There were no significant differences in the age of patients in the individuals with vascular fenestration (p > 0.05). VA fenestration was slightly more common in men (16.67%) than in women (5.41%). However, these differences were not statistically significant (p = 0.216). Limitations: Our study has several limitations, including selection bias regarding examined population. Second, we assume that the total number of fenestrations detected in our study was underestimated due to the limitations of the CT method in comparison to other radiologic modalities. Conclusions: Cerebral arterial fenestrations are rare vascular malformations. The ACA is the most common localization of fenestrations, followed by BA and AComA. Fenestrations of cerebral arteries insignificantly increase the risk of cerebral aneurysm formation. Further prospective studies are necessary to make this association more precise.

Low-Cost Cranioplasty-A Systematic Review of 3D Printing in Medicine.

The high cost of biofabricated titanium mesh plates can make them out of reach for hospitals in low-income countries. To increase the availability of cranioplasty, the authors of this work investigated the production of polymer-based endoprostheses. Recently, cheap, popular desktop 3D printers have generated sufficient opportunities to provide patients with on-demand and on-site help. This study also examines the technologies of 3D printing, including SLM, SLS, FFF, DLP, and SLA. The authors focused their interest on the materials in fabrication, which include PLA, ABS, PET-G, PEEK, and PMMA. Three-dimensional printed prostheses are modeled using widely available CAD software with the help of patient-specific DICOM files. Even though the topic is insufficiently researched, it can be perceived as a relatively safe procedure with a minimal complication rate. There have also been some initial studies on the costs and legal regulations. Early case studies provide information on dozens of patients living with self-made prostheses and who are experiencing significant improvements in their quality of life. Budget 3D-printed endoprostheses are reliable and are reported to be significantly cheaper than the popular counterparts manufactured from polypropylene polyester.

Metallic Implants Used in Lumbar Interbody Fusion.

Over the last decade, pedicle fixation systems have evolved and modifications in spinal fusion techniques have been developed to increase fusion rates and improve clinical outcomes after lumbar interbody fusion (LIF). Regarding materials used for screw and rod manufacturing, metals, especially titanium alloys, are the most popular resources. In the case of pedicle screws, that biomaterial can be also doped with hydroxyapatite, CaP, ECM, or tantalum. Other materials used for rod fabrication include cobalt-chromium alloys and nitinol (nickel-titanium alloy). In terms of mechanical properties, the ideal implant used in LIF should have high tensile and fatigue strength, Young's modulus similar to that of the bone, and should be 100% resistant to corrosion to avoid mechanical failures. On the other hand, a comprehensive understanding of cellular and molecular pathways is essential to identify preferable characteristics of implanted biomaterial to obtain fusion and avoid implant loosening. Implanted material elicits a biological response driven by immune cells at the site of insertion. These reactions are subdivided into innate (primary cellular response with no previous exposure) and adaptive (a specific type of reaction induced after earlier exposure to the antigen) and are responsible for wound healing, fusion, and also adverse reactions, i.e., hypersensitivity. The main purposes of this literature review are to summarize the physical and mechanical properties of metal alloys used for spinal instrumentation in LIF which include fatigue strength, Young's modulus, and corrosion resistance. Moreover, we also focused on describing biological response after their implantation into the human body. Our review paper is mainly focused on titanium, cobalt-chromium, nickel-titanium (nitinol), and stainless steel alloys.