Intercalary Bone Grafts for Joint and Limb Preservation in 17 Dogs with High-Grade Malignant Tumors of the Diaphysis

Nanocarriers in Veterinary Medicine: A Challenge for Improving Osteosarcoma Conventional Treatments

In recent years, several nanocarrier-based drug delivery systems, such as polymeric nanoparticles, solid lipid nanoparticles, metallic nanoparticles, liposomes, and others, have been explored to target and treat a wide variety of diseases. Their employment has brought many benefits, not only to human medicine but also to veterinary medicine, albeit at a slower rate. Soon, the use of nanocarriers could revolutionize the animal health sector, and many veterinary therapies will be more effective as a result. The purpose of this review is to offer an overview of the main applications of nanocarriers in the veterinary field, from supplements for animal health and reproduction to nanovaccines and nanotherapies. Among the major pathologies that can affect animals, special attention is given to canine osteosarcoma (OSA): a comparison with human OSA is provided and the main treatment options are reviewed emphasizing the benefits that nanocarriers could bring in the treatment of this widespread disease.

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.

Ulnar ostectomy decreases the stability of canine cadaver carpi as assessed with stress radiography

Distal ulnar ostectomy may be performed palliatively in patients with distal ulnar osteosarcoma. Concurrent arthrodesis of the carpus has been proposed to counteract joint instability following transection of carpal ligaments associated with removal of the distal ulna. The objective of this prospective one group pretest, posttest study was to assess stability of the carpus following distal ulnar ostectomy using pre- and postoperative stress radiographic views in a group of canine cadaver limbs. Seven thoracic limbs from six canine cadavers weighing more than 20 kg were obtained. Lateral and dorsopalmar, extended lateral, medial stress, and lateral stress radiographs were made before and after distal ulnar ostectomy. Presurgical canine cadaver carpal angle measurements were as follows (mean ± standard deviation): extension 205.9° ± 5.4; medial stress 25.1° ± 5.7; and lateral stress 13.3° ± 5.2°. Cadaver limb joint angles exceeded those previously reported in live dogs. A significant increase in carpal angle was noted following ulnar ostectomy. The mean increases in carpal angle were as follows: (mean ± standard deviation (95% confidence interval)): extension 6.2° ± 4.9 (2.6-9.8) (P = 0.007); medial stress 3.2° ± 3.0 (1.0-5.5) (P = 0.015); lateral stress 6.2° ± 5.2 (2.4-10.1) (P = 0.010). Findings from this cadaver study support the use of supplementary stabilization for clinical patients undergoing distal ulnar ostectomy. Future studies are needed in clinical patients to evaluate changes in limb positioning and gait associated with distal ulnar ostectomy.

Mechanical properties of canine osteosarcoma-affected antebrachia

OBJECTIVE

To determine the influence of neoplasia on the biomechanical properties of canine antebrachia.

STUDY DESIGN

Ex vivo biomechanical study.

SAMPLE POPULATION

Osteosarcoma (OSA)-affected canine antebrachia (n = 12) and unaffected canine antebrachia (n = 9).

METHODS

Antebrachia were compressed in axial loading until failure. A load-deformation curve was used to acquire the structural mechanical properties of neoplastic and unaffected specimens. Structural properties and properties normalized by body weight (BW) and radius length were compared using analysis of variance (ANOVA). Modes of failure were compared descriptively.

RESULTS

Neoplastic antebrachia fractured at, or adjacent to, the OSA in the distal radial diaphysis. Unaffected antebrachia failed via mid-diaphyseal radial fractures with a transverse cranial component and an oblique caudal component. Structural mechanical properties were more variable in neoplastic antebrachia than unaffected antebrachia, which was partially attributable to differences in bone geometry related to dog size. When normalized by dog BW and radial length, strength, stiffness, and energy to yield and failure, were lower in neoplastic antebrachia than in unaffected antebrachia.

CONCLUSIONS

OSA of the distal radial metaphysis in dogs presented for limb amputation markedly compromises the structural integrity of affected antebrachia. However, biomechanical properties of affected bones was sufficient for weight-bearing, as none of the neoplastic antebrachia fractured before amputation. The behavior of tumor invaded bone under cyclic loading warrants further investigations to evaluate the viability of in situ therapies for bone tumors in dogs.

Percutaneous cementoplasty in the palliative, multimodal treatment of primary bone tumors of the distal aspect of the radius in four dogs

OBJECTIVE

To (1) evaluate the analgesic effect of percutaneous cementoplasty (PC) in dogs with primary bone tumor (PBT) of the distal aspect of the radius and (2) evaluate the impact on the course of disease by adding PC to a palliative, multimodal treatment protocol in these dogs.

STUDY DESIGN

Prospective pilot study.

ANIMALS

Dogs (n=4) with PBT of the distal aspect of the radius.

METHODS

Tumor lesions were filled percutaneously with polymethylmethacrylate under fluoroscopic guidance. Pamidronate was administered once in a week before PC. Radiotherapy and chemotherapy were initiated 2 and 6 weeks after PC, respectively. Force plate analysis was performed immediately before 2, and 6 weeks after PC. Survival time was defined from PC to euthanasia.

RESULTS

Two dogs had a significant increase in peak vertical force 2 weeks after PC (P=.043) and remained free of lameness for 18 and 20 weeks, respectively. One dog had an acute relapse after an initially lame-free period of 10 days. The remaining dog failed to improve (P=.686). Three dogs developed at least 2 complications including transient worsening of the lameness after PC, cement leakage, wound infection and suspected thromboembolism in combination with cough and anemia. Median survival was 4.8 months (range, 1-5.7 months).

CONCLUSIONS

PC in combination with pamidronate significantly improved lameness in 2 dogs; however, PC is not risk-free. Deep wound infection, intraarticular cement leakage, and venous thrombosis were the main complications.

CLINICAL RELEVANCE

PC might be a useful addition to established palliative, multimodal treatment protocols in dogs with PBT; however, because of the complications encountered PC warrants further study before routine use can be considered.

Intraoperative Radiation for Limb Sparing of the Distal Aspect of the Radius Without Transcarpal Plating in Five Dogs

OBJECTIVES

To evaluate intraoperative irradiation (IORT) as a method of limb spare with preservation of the radiocarpal joint.

STUDY DESIGN

Prospective case series.

ANIMALS

Dogs (n=5) with stage II sarcoma of the distal aspect of the radius.

METHODS

A bone segment containing the tumor was isolated surgically, treated by IORT, reimplanted, and secured by internal fixation. In 1 dog, the postradiation tumor bed was curetted and filled with bone cement. Dogs were administered alternating adriamycin and carboplatin starting 2 weeks after IORT and monitored at regular intervals.

RESULTS

Four dogs had osteosarcoma and 1 had undifferentiated sarcoma. Implant failure (n=3), deep tissue infection (3), and pathologic fracture (3) resulted in amputation (3) or pancarpal plating (2). The dog with undifferentiated sarcoma was euthanatized because of suspected tumor recurrence 4 months postoperatively. Osteotomy healing was documented by radiography (1), histopathology (2), or by direct observation (2).

CONCLUSIONS

A technique for limb-sparing surgery of the distal portion of the radius in dogs using IORT had advantages include healing of the autograft and a source for a perfectly fitting autograft but did not appear to offer any advantage with respect to infection rate. Long-term preservation of the radiocarpal joint was not successful.

CLINICAL RELEVANCE

It was not possible to preserve the function of the radiocarpal joint and so this technique cannot be recommended currently. Further study is needed to evaluate whether or not IORT can be considered in combination with pancarpal plating and possibly curettage and cementation of the tumor to prevent subchondral bone collapse.

Limb-Sparing Surgery in a Dog with Osteosarcoma of the Proximal Femur

OBJECTIVE

To report successful limb-sparing surgery in a dog with a proximal femoral osteosarcoma (OSA) using a composite allograft-prosthetic technique.

STUDY DESIGN

Case report.

ANIMAL

Client-owned dog.

METHODS

A stage IIB OSA of the proximal aspect of the femur was resected in accordance with oncologic and limb-sparing principles. The osseous defect was reconstructed with a proximal femoral allograft and cemented, long-stemmed femoral prosthesis. Soft tissue reconstruction was achieved by suturing host tendons to their respective allogeneic tendons on the allograft. Coxofemoral joint function was preserved using standard total hip arthroplasty techniques.

RESULTS

Limb-sparing surgery of the proximal aspect of the femur using a composite allograft-prosthetic technique resulted in excellent limb function. Postoperative complications included aseptic loosening of the femoral composite graft and allograft nonunion, which required revision, traumatic implant luxation, and local tumor recurrence. Limb function was excellent after surgical stabilization of the allograft nonunion but deteriorated after implant luxation 270 days postlimb-sparing surgery. Pulmonary and skeletal metastases were diagnosed and local tumor recurrence suspected 596 and 650 days postoperatively, respectively. The dog was euthanatized 688 days after limb-sparing surgery as a result of progressive local and metastatic disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Limb-sparing surgery for dogs with primary bone tumors of the proximal aspect of the femur is feasible with good functional results.