A Novel Tantalum-Containing Bioglass. Part I. Structure and Solubility

Bio glasses are employed for surgical augmentation in a range of hard tissue applications. Tantalum is a bioactive and biocompatible transition metal that has been used as an orthopedic medical device. It has a range of biological and physical properties that make its incorporation into ionic form into bioactive glass systems promising for various clinical applications. The work herein reports the characterization and properties of novel tantalum-containing glasses. A series of glasses based on the system 48SiO2-(36-X)ZnO-6CaO-8SrO-2P2O5-XTa2O5 with X varying from 0 mol% (TA0) to 0.5 mol% (TA2) were synthesized. The addition of small amounts of Ta2O5 did not cause crystallization of the glasses but increasing Ta2O5 content at the expense of ZnO was found to result in an increased number of bridging oxygens (BOs). This, along with the data recorded by differential thermal analysis (DTA) and magic angle spinning-nuclear magnetic resonance (MAS-NMR), confirms that Ta acts as a glass former in this series. Solubility experiments showed that minor changes in the glass structure caused by Ta incorporation (0.5 mol%) exhibited greater cumulative % weight loss, pH values and cumulative Zn2+ and Sr2+ ion concentration over a period of 30 days of maturation, when compared to Ta2O5-free glasses. The results presented in this article confirm that replacing ZnO with Ta2O5 in silicate glasses results in the formation of stronger bonds within the glass network without any adverse effects on the solubility of the glasses prepared from them

A Novel Tantalum-Containing Bioglass. Part II. Development of a Bioadhesive for Sternal Fixation and Repair

With over a million median sternotomy surgeries performed worldwide every year, sternal wound complications have posed a serious risk to the affected patients. A rigid therapeutic sternal fixation device has therefore become a necessity. In this work, the incorporation of up to 0.5 mol% of tantalum pentoxide (Ta2O5), in exchange for zinc oxide (ZnO), into the SiO2-ZnO-CaO-SrO-P2O5 glass system is presented. The effect of Ta incorporation on the physical, chemical and biological properties of the glass polyalkenoate cements (GPCs) prepared from them have been presented in this manuscript. The data obtained have confirmed that Ta2O5 incorporation into the reference glass system results in increased working times, radiopacity, ion solubility, and long-term mechanical stability. The formulated glass systems have also shown clear antibacterial and antifungal activity against both Gram-negative (Escherichia coli) and Gram-positive prokaryotes (Staphylococcus aureus and Streptococcus epidermidis), as well as eukaryotes (Fusarium solani). Cytotoxicity testing showed that Ta incorporation results in no toxicity effect and may simulate osseo-integration when tested in animal models. These new metallic-containing biomaterial adhesives have been developed for sternal fixation and repair. As a permanent implant, the formulated adhesives can be used in conjunction with sternal cable ties to offer optimal fixation for patients and reduce post-operative complications such as bacterial infection and pain from micro-motion

A Review of Sternal Closure Techniques

Sternotomy and sternal closure occur prior to and post cardiac surgery, respectively. Although post-operative complications associated with poor sternal fixation can result in morbidity, mortality, and considerable resource utilization, sternotomy is preferred over other methods such as lateral thoracotomy. Rigid sternal fixation is associated with stability and reduced incidence of post-operative complications. This is a comprehensive review of the literature evaluating in vivo, in vitro, and clinical responses to applying commercial and experimental surgical tools for sternal fixation after median sternotomy. Wiring, interlocking, plate-screw, and cementation techniques have been examined for closure, but none have experienced widespread adoption. Although all techniques have their advantages, serious post-operative complications were associated with the use of wiring and/or plating techniques in high-risk patients. A fraction of studies have analyzed the use of sternal interlocking systems and only a single study analyzed the effect of using kryptonite cement with wires. Plating and interlocking techniques are superior to wiring in terms of stability and reduced rate of post-operative complications; however, further clinical studies and long-term follow-up are required. The ideal sternal closure should ensure stability, reduced rate of post-operative complications, and a short hospitalization period, alongside cost-effectiveness. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav