Mechanical properties of canine osteosarcoma-affected antebrachia

Evaluation of cortical bone strength using a quantitative ultrasound measurement device in dogs

This study was performed to evaluate cortical bone strength in dogs using a quantitative ultrasound measurement device. In this study, 16 clinically healthy dogs with no lameness underwent measurement of the ultrasound propagation velocity of cortical bone (namely, speed of sound [SOS]) at the radius and tibia. Additionally, computed tomography examination with a calibration phantom was performed in 10 dogs. We calculated the bone mineral density (BMD) and Young's modulus from the computed tomography data using bone strength evaluation software. SOS, BMD, and Young's modulus were statistically compared between the radius and tibia. In addition, we examined the correlation between SOS and BMD and between SOS and Young's modulus. We also examined the correlation between SOS and age in the 13 dogs whose age was known. BMD and Young's modulus were not significantly different between the radius and tibia, but SOS was significantly different (P<0.05). Moreover, SOS and BMD showed a positive correlation in both radius and tibia. Similarly, SOS and Young's modulus showed a positive correlation. In addition, SOS and age showed a strong positive correlation (radius: r=0.77, P<0.05, tibia: r=0.83, P<0.05). Our finding that SOS of the radius and tibia cortical bone was correlated with BMD and Young's modulus indicates that quantitative ultrasound can be useful for evaluating cortical bone strength in dogs.

Configuration of pathologic fractures in dogs with osteosarcoma following stereotactic body radiation therapy: A retrospective analysis

For some cases of canine appendicular osteosarcoma (OSA), limb-sparing treatment options are often desired, one of which is stereotactic body radiation therapy (SBRT). A major complication of SBRT is fracture of the irradiated bone at the site of treatment. The present study evaluated 127 appendicular OSA sites in 122 dogs treated with SBRT to identify the most common pathologic fracture locations and configurations. A total of 50 tumours experienced a pathologic fracture, and 38 had imaging sufficient to identify fracture configuration. The distal tibia was more likely to develop a fracture than other sites. Multiple types of fracture configuration (transverse, oblique, spiral and comminuted) were observed. The distal radius was significantly more likely to develop a transverse fracture than other sites. Documentation of fracture location and configuration leads to the identification of the forces contributing to fracture occurrence, since each configuration is a result of different forces acting on each affected bone. Such knowledge is imperative for the development of new approaches to diminish the occurrence of pathologic fractures.

Tissue engineered platforms for studying primary and metastatic neoplasm behavior in bone

Cancer is the second leading cause of death in the United States, claiming more than 560,000 lives each year. Osteosarcoma (OS) is the most common primary malignant tumor of bone in children and young adults, while bone is a common site of metastasis for tumors initiating from other tissues. The heterogeneity, continual evolution, and complexity of this disease at different stages of tumor progression drives a critical need for physiologically relevant models that capture the dynamic cancer microenvironment and advance chemotherapy techniques. Monolayer cultures have been favored for cell-based research for decades due to their simplicity and scalability. However, the nature of these models makes it impossible to fully describe the biomechanical and biochemical cues present in 3-dimensional (3D) microenvironments, such as ECM stiffness, degradability, surface topography, and adhesivity. Biomaterials have emerged as valuable tools to model the behavior of various cancers by creating highly tunable 3D systems for studying neoplasm behavior, screening chemotherapeutic drugs, and developing novel treatment delivery techniques. This review highlights the recent application of biomaterials toward the development of tumor models, details methods for their tunability, and discusses the clinical and therapeutic applications of these systems.

Impact of microwave ablation treatment on the biomechanical properties of the distal radius in the dog: A cadaveric study

OBJECTIVE

To determine whether microwave ablation (MWA) modifies the biomechanical properties of the normal distal radius in the dog to better estimate the clinical impact of MWA as a tool for the treatment of neoplastic bone lesions.

STUDY DESIGN

Biomechanical experimental study.

SAMPLE POPULATION

Sixteen pairs of dog forelimbs from 16 canine cadavers.

METHODS

From each pair of forelimbs, one radius was randomly assigned to an MWA group, and the other radius was randomly assigned to a control group. Bone tunnels were created in each distal radial epiphysis for a length of 6 cm toward the middiaphysis. In the MWA group, the ablation probe was inserted into the bone tunnel for a series of three ablation treatments. Specimens were then tested in three-point bending to acute failure with the middle point located 3 cm from the distal articular surface (middle of the ablated zone). Load and displacement were continuously recorded to determine maximum displacement and peak load before failure. Data were analyzed with noninferiority tests.

RESULTS

The mean peak loads for the control group and MWA group were 1641.9 N and 1590.9 N, respectively. Microwave ablation-treated radii were not biomechanically inferior to control radii (P < .0001).

CONCLUSION

Microwave ablation of normal cadaveric dog distal radii did not affect the maximum displacement and peak load before failure.

CLINICAL SIGNIFICANCE

Microwave ablation does not affect biomechanical bending properties of the distal radius in the dog. Future studies, both cadaveric and in vivo, are required to evaluate the impact of MWA on neoplastic bone.