Polyethylene glycol improves elution properties of polymethyl methacrylate bone cements

A Toolbox of Bone Consolidation for the Interventional Radiologist

Bone consolidation is increasingly used in the treatment of both benign and malignant bone conditions. Percutaneous vertebroplasty, for example, has been shown to be useful in vertebral compression fractures in the VAPOUR trial which showed its superiority to placebo for pain reduction in the treatment of acute vertebral compressive fractures. Further tools have since been developed, such as kyphoplasty, spinal implants, and even developments in bone cements itself in attempt to improve outcome, such as chemotherapy-loaded cement or cement replacements such as radio-opaque silicon polymer. More importantly, bone fixation and its combination with cement have been increasingly performed to improve outcome. Interventional radiologists must first know the tools available, before they can best plan for their patients. This review article will focus on the tool box available for the modern interventional radiologist.

Comprehensive evaluation and advanced modification of polymethylmethacrylate cement in bone tumor treatment

Bone tumors are invasive diseases with a tendency toward recurrence, disability, and high mortality rates due to their grievous complications. As a commercial polymeric biomaterial, polymethylmethacrylate (PMMA) cement possesses remarkable mechanical properties, injectability, and plasticity and is, therefore, frequently applied in bone tissue engineering. Numerous positive effects in bone tumor treatment have been demonstrated, including biomechanical stabilization, analgesic effects, and tumor recurrence prevention. However, to our knowledge, a comprehensive evaluation of the application of the PMMA cement in bone tumor treatment has not yet been reported. This review comprehensively evaluates the efficiency and complications of the PMMA cement in bone tumor treatment, for the first time, and introduces advanced modification strategies, providing an objective and reliable reference for the application of the PMMA cement in treating bone tumors. We have also summarized the current research on modifications to enhance the anti-tumor efficacy of the PMMA cement, such as drug carriers and magnetic hyperthermia.

PMMA Bone Cement Composite Functions as an Adjuvant Chemotherapeutic Platform for Localized and Multi-Window Release During Bone Reconstruction

Primary bone tumor resections often result in critical size defects, which then necessitate challenging clinical management approaches to reconstruct. One such intervention is the Masquelet technique, in which poly(methyl methacrylate) (PMMA) bone cement is placed as a spacer temporarily while adjuvant chemotherapeutics are administered systemically. The spacer is later removed and replaced with bone autograft. Local recurrence remains an important and devastating problem, therefore, a system capable of locally delivering chemotherapeutics would present unique advantages. In this work, a refillable chemotherapeutic (doxorubicin, DOX) delivery platform comprised of PMMA bone cement and insoluble γ-cyclodextrin (γ-CD) polymeric microparticles is developed and explored towards application as a temporary adjuvant chemotherapeutic spacer. The system is characterized for porosity, mechanical strength, DOX filling and refilling capacity, elution kinetics, and cytotoxicity. Since residual chemotherapeutics could adversely impact bone healing, it is important that virtually all DOX be released from material. Composites containing 15wt% γ-CD microparticles demonstrate 100% DOX release within 100 days, whereas only 6% DOX is liberated from PMMA with free DOX over same period. Refillable properties of PMMA composite system may find utility for customizing dosing regimens. Findings suggest that PMMA composites could have potential as chemotherapeutic delivery platforms to assist in bone reconstruction. This article is protected by copyright. All rights reserved.

Bone cement as a local chemotherapeutic drug delivery carrier in orthopedic oncology: A review

Metastatic bone lesions are common among patients with advanced cancers. While chemotherapy and radiotherapy may be prescribed immediately after diagnosis, the majority of severe metastatic bone lesions are treated by reconstructive surgery, which, in some cases, is followed by postoperative radiotherapy or chemotherapy. However, despite recent advancements in orthopedic surgery, patients undergoing reconstruction still have the risk of developing severe complications such as tumor recurrence and reconstruction failure. This has led to the introduction and evaluation of poly (methyl methacrylate) and inorganic bone cements as local carriers for chemotherapeutic drugs (usually, antineoplastic drugs (ANPDs)). The present work is a critical review of the literature on the potential use of these cements in orthopedic oncology. While several studies have demonstrated the benefits of providing high local drug concentrations while minimizing systemic side effects, only six studies have been conducted to assess the local toxic effect of these drug-loaded cements and they all reported negative effects on healthy bone structure. These findings do not close the door on chemotherapeutic bone cements; rather, they should assist in materials selection when designing future materials for the treatment of metastatic bone disease.

PEGDA/HA mineralized hydrogel loaded with Exendin4 promotes bone regeneration in rat models with bone defects by inducing osteogenesis

Scaffolds with osteogenic differentiation function play an important role in the healing process of bone defects. Here, we designed a high strength Poly(ethyleneglycol) diacrylate/Hydroxyapatite (PEGDA/HA) mineralized hydrogel loaded with Exendin4 for inducing osteogenic differentiation. In this study, PEGDA hydrogel was prepared by photo initiating method. PEGDA/HA mineralized hydrogel was prepared by in-situ precipitation method, and Exendin4 was loaded by gel adsorption. The effects of different calcium and phosphorus concentrations on the strength and Exendin4 release of PEGDA/HA hydrogels were investigated. Rat models of bone defect were made and randomly divided into 5 groups. The experimental group was implanted with PEGDA hydrogel, Exendin4-PEGDA hydrogel, PEGDA/HA mineralized hydrogel, Exendin4-PEGDA/HA mineralized hydrogel, and no materials were implanted in the blank control group. Computed tomography (CT) and histology were observed 4 and 8 weeks after operation. Our results revealed that the PEGDA/HA mineralized hydrogel had porous structure, high mechanical strength and good biocompatibility. In vitro release test showed that the mineralized hydrogel exhibited good sustained release profile within 20 d. The animal experiments showed that the mineralized hydrogel accelerated the formation of new bone after 4 and 8 weeks, and formed a seamless union on the defected bone area after 8 weeks. In conclusions, The Exendin4-PEGDA/HA mineralized hydrogel can effectively repair bone defects in rats, and it is expected to be used as a biomaterial for human bone tissue repair.

Drug-eluting implants for the suppression of metastatic bone disease: current insights

INTRODUCTION

The fixation of impending or pathologic fractures is challenging and their successful management can have a favourable impact on the quality of life of the patient. The progression of the metastatic bone disease can cause significant pain and disability but also could result in the loosening and subsequent failure of the implants. To prevent the additional local growth, postoperative radiotherapy is often recommended, and many patients receive endocrine or chemotherapy.

AREAS COVERED

Several reports support the antineoplastic drugs to bone cement as an adjuvant to improve implant stability as well as to prevent local cancer progression and failure of reconstructive devices used to treat patients with pathologic fractures. The aim of the present review is to present our current understanding on the effect of local delivery of antineoplastic drugs at the bone site.

EXPERT COMMENTARY

Encouraging evidence support the application of bone cement loaded with antineoplastic drugs to fill defects and strengthen the fixation of orthopaedic implants. This is an inexpensive and safe method that can improve implant stability, prevent local cancer progression and failure of reconstructive devices. To fully evaluate its clinical effectiveness randomized clinical studies are needed.