A developmental model for free vascularized bone transfers in the dog

Area of Science:

• Orthopedic Surgery
• Vascular Surgery
• Regenerative Medicine

Background:

• Autogenous bone grafts are crucial for skeletal reconstruction.
• Vascularized bone grafts offer potential advantages over avascular grafts.
• Microvascular techniques enable direct revascularization of bone segments.

Purpose of the Study:

• To evaluate the osteogenic potential and viability of autogenous free vascularized bone transfers.
• To compare revascularized bone grafts with avascular bone grafts.
• To establish a reliable method for free vascularized bone transfer using the ulna.

Main Methods:

• Development of an autogenous free vascular bone transfer technique using the ulna and its vascular pedicle (common interosseous artery and vein).
• Performance of four heterotopic vascularized ulna-to-tibia transfers with microvascular anastomosis.
• Comparison with two avascular bone transfers.
• Assessment of graft viability and osteogenesis using technetium-labeled polyphosphate bone scanning, radiography, and histology.

Main Results:

• Successful microvascular anastomosis was achieved in three out of four vascular transfers, confirmed by early bone scanning.
• Radiographic analysis revealed significantly more periosteal new bone and callus formation in successfully revascularized grafts compared to failed vascular and avascular grafts.
• Histological examination confirmed viable bone with intact medullary and periosteal vascular supply in successfully revascularized grafts.

Conclusions:

• Autogenous free vascularized bone transfers using the ulna demonstrate superior osteogenic potential and viability.
• Microvascular anastomosis is critical for successful revascularization and enhanced bone regeneration.
• This technique provides a viable option for skeletal reconstruction requiring vascularized bone grafts.