Distraction osteogenesis assisted by tissue engineering in an irradiated mandible: a case report

Distraction osteogenesis (DO) can provide predictable bone regeneration without grafting procedures but requires long treatment time and forms less bone transverse to the direction of distraction. To promote 3-dimensional bone formation and shorten the consolidation period, tissue-engineered osteogenic material (injectable bone) was applied in a patient who was being treated with vertical DO with an osteocutaneous fibular flap to reconstruct the mandible. The material, which comprised autologous mesenchymal stem cells culture-expanded then induced to be osteogenic in character and platelet-rich plasma (PRP) activated with thrombin and calcium chloride, was infiltrated into the distracted tissue at the end of distraction and injected into a space created labially with a titanium mesh at implant placement. The infiltration contributed to full consolidation of the regenerate for 3 months, and the injection thickened the regenerated ridge and bridged a gap between the native mandible and distracted fibula. The reconstructed mandible was expanded from 10 mm to 25 mm in height despite a lacerated and opened labial periosteum in the distracted area. Six implants 18 mm in length were placed and subsequently achieved osseointegration. The cutaneous flap covering the implants was trimmed, and the palatal mucosa was transplanted to the regenerated ridge for vestibuloplasty. These raw surfaces were covered with PRP; within 3 weeks, they had attained an epithelium. The implants have supported a fixed prosthesis with adequate surrounding bone and attached mucosa. DO was assisted by tissue engineering and became effective in restoring the compromised mandible.