Microstructure and biomechanical characteristics of bone substitutes for trauma and orthopaedic surgery

Abstract. BACKGROUND: Many (artificial) bone substitute materials are currently available for use in orthopaedic trauma surgery. Objective data on their biological and biomechanical characteristics, which determine their clinical application, is mostly lacking. The aim of this study was to investigate structural and in vitro mechanical properties of nine bone substitute cements registered for use in orthopaedic trauma surgery in the Netherlands. METHODS: Seven calcium phosphate cements (BoneSource®, Calcibon®, ChronOS®, Eurobone®, HydroSet™, Norian SRS®, and Ostim®), one calcium sulphate cement (MIIG® X3), and one bioactive glass cement (Cortoss®) were tested. Structural characteristics were measured by micro-CT scanning. Compression strength and stiffness were determined following unconfined compression tests. RESULTS: Each bone substitute had unique characteristics. Mean total porosity ranged from 53% (Ostim®) to 0.5% (Norian SRS®). Mean pore size exceeded 100 μm only in Eurobone® and Cortoss® (162.2 ± 107.1 μm and 148.4 ± 70.6 μm, respectively). However, 230 μm pores were found in Calcibon®, Norian SRS®, HydroSet™, and MIIG® X3. Connectivity density ranged from 27/cm3 for HydroSet™ to 0.03/cm3 for Calcibon®. The ultimate compression strength was highest in Cortoss® (47.32 MPa) and lowest in Ostim® (0.24 MPa). Young's Modulus was highest in Calcibon® (790 MPa) and lowest in Ostim® (6 MPa). CONCLUSIONS: The bone substitutes tested display a wide range in structural properties and compression strength, indicating that they will be suitable for different clinical indications. The data outlined here will help surgeons to select the most suitable products currently available for specific clinical indications

Multidisciplinary Treatment and Survival of Patients with Vertebral Metastases from Thyroid Carcinoma

C1 - Journal Articles RefereedBACKGROUND: Distant metastases from differentiated thyroid carcinoma occur in up to 20% of cases and represent the most frequent cause of thyroid cancer-related death. Metastatic disease to the spine has the potential to cause severe morbidity, including pain, neurological deficit, and paraplegia. SUMMARY: We present a case series of eight consecutive patients with symptomatic spinal metastases due to thyroid carcinoma treated by our multidisciplinary team consisting of spinal surgeons, oncologists, and radiologists, with management of each case determined by our surgical algorithm. Four patients underwent surgical decompression and stabilization for spinal metastases causing instability, spinal cord compression, neurological deficit, or intractable pain. Three patients underwent vertebroplasty for focal mechanical pain due to osteolytic metastases in the absence of significant spinal cord compression or spinal instability; one of these patients required subsequent surgical decompression for spinal cord compression. One patient was nonoperatively treated. All patients underwent total thyroidectomy for the primary cancer and adjuvant radioiodine-131 treatment. The only patient with poorly differentiated thyroid cancer, which was refractory to radioiodine-131 died at 6 months after vertebroplasty procedures for symptomatic spinal metastases. One patient with medullary thyroid carcinoma died at 18 months after vertebroplasty. All remaining six patients who had well-differentiated papillary or follicular thyroid carcinoma were alive at an average of 50 months (range: 17-96 months) after diagnosis and treatment of symptomatic spinal metastases and were ambulant, independent, and able to perform activities of daily living and had no significant pain or neurologic symptoms. CONCLUSION: The potential for long-term survival of several years following development of spinal metastases should be considered during the counseling and decision-making process for patients with thyroid cancer

Image-based control of the magnetic resonance imaging-guided focused ultrasound thermotherapy

articleInternational audienceMagnetic resonance imaging (MRI)-guided focused ultrasound surgery (FUS) is a full noninvasive approach for localized thermal ablation of deep tissues, coupling the following: (1) a versatile, nonionizing physical agent for therapy and (2) a state-of-the art diagnosis and on-line monitoring tool. A commercially available, Food and Drug Administration-approved device using the MRI-guided FUS exists since 2004 for the ablation of benign tumors (uterine fibroids); however, the ultimate goal of the technological, methodological, and medical research in this field is to provide a clinical-routine tool for fighting localized cancer. When addressing cancer applications, the accurate spatial control of the delivered thermal dose is mandatory. Contiguous destruction of the target volume must be achieved in a minimum time, whereas sparing as much as possible the neighboring healthy tissues and especially when some adjacent regions are critical. This paper reviews some significant developments reportedand review literature in the literature related to the image-based control of the FUS therapy for kidney, breast, prostate, and brain, including the own experience of the authors on the active feedback control of the temperature during FUS ablation. In addition, preliminary results of an original study of MRI-guided FUS ablation of VX2 carcinoma in kidney, under active temperature control, are described here

Automatic feedback control of the temperature for MRI-guided therapeutic ultrasound

articleInternational audienceHigh intensity ultrasound was demonstrated to provide an effective and minimally invasive therapeutic tool for in situ ablation of localized cancers. MRI guidance of the treatment allows excellent volume targeting, together with accurate on line measurement of the actual temperature in tissues. Spatial and temporal automatic feedback control of the procedure can guarantee effectiveness and safety against tissue and individual biovariability of physical parameters. This paper provides a general overview of authors' experience on the active control of the therapy with MR-compatible applicators of extracorporeal and endocavitary high intensity ultrasound

In vivo mathematical modeling of tumor growth from imaging data : soon to come in the future ?

International audienc

In vivo mathematical modeling of tumor growth from imaging data : soon to come in the future ?

International audienc

Current role of interventional radiology in the management of visceral and bone metastases from thyroid cancer.

The metastatic disease from thyroid cancer represents a complex clinical scenario, which mandates a case-based multi-disciplinary approach in tertiary referral centers. Direct localised treatments such as minimally invasive interventional radiology procedures can play a vital role in providing a timely palliative or curative treatment in accordance with the patients' clinical status. In this narrative review, we present the current status of interventional radiology treatments for the management of thyroid cancer distant metastases.This article is freely available via the publisher's site. Click on the Additional Link above to access the full-text via the publisher's site

Organometallic synthesis of CuO nanoparticles: Application in low-temperature CO detection

International audienceA metal–organic approach has been employed for the preparation of anisotropic CuO nanoparticles. These nanostructures have been characterized by transmission and high resolution transmission electron microscopy, field‐emission scanning electron microscopy, X‐ray powder diffraction, Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The CuO nanoparticles have been deposited as gas‐sensitive layers on miniaturized silicon devices. At an operating temperature of 210 °C, the sensors present an optimum response toward carbon monoxide correlated with a fast response (Rn) and short recovery time. A high sensitivity to CO (Rn≈150 %, 100 ppm CO, RH 50 %) is achieved. These CuO nanoparticles serve as a very promising sensing layer for the fabrication of selective CO gas sensors working at a low temperature