Radiological Assessment of Bioengineered Bone in a Muscle Flap for the Reconstruction of Critical-Size Mandibular Defect

Abstract

This study presents a comprehensive radiographic evaluation of bone regeneration within a pedicled muscle flap for the reconstruction of critical size mandibular defect. The surgical defect (20 mm×15 mm) was created in the mandible of ten experimental rabbits. The masseter muscle was adapted to fill the surgical defect, a combination of calcium sulphate/hydroxyapatite cement (CERAMENT™ |SPINE SUPPORT), BMP-7 and rabbit mesenchymal stromal cells (rMSCs) was injected inside the muscle tissue. Radiographic assessment was carried out on the day of surgery and at 4, 8, and 12 weeks postoperatively. At 12 weeks, the animals were sacrificed and cone beam computerized tomography (CBCT) scanning and micro-computed tomography (µ-CT) were carried out. Clinically, a clear layer of bone tissue was identified closely adherent to the border of the surgical defect. Sporadic radio-opaque areas within the surgical defect were detected radiographically. In comparison with the opposite non operated control side, the estimated quantitative scoring of the radio-opacity was 46.6% ±15, the mean volume of the radio-opaque areas was 63.4% ±20. Areas of a bone density higher than that of the mandibular bone (+35% ±25%) were detected at the borders of the surgical defect. The micro-CT analysis revealed thinner trabeculae of the regenerated bone with a more condensed trabecular pattern than the surrounding native bone. These findings suggest a rapid deposition rate of the mineralised tissue and an active remodelling process of the newly regenerated bone within the muscle flap. The novel surgical model of this study has potential clinical application; the assessment of bone regeneration using the presented radiolographic protocol is descriptive and comprehensive. The findings of this research confirm the remarkable potential of local muscle flaps as local bioreactors to induce bone formation for reconstruction of maxillofacial bony defects.

Revascularization and angiogenesis for bone bioengineering in the craniofacial region: a review

“…The aim of the clinical case reports and ex vivo experiments was to target the use of the skeletal muscles as a bioreactor. These case studies have been discussed [ 15 , 16 , 18 – 20 ] in vivo experiments. For these reasons, most of the case studies have suggested the use of the skeletal muscles as a biomimetic supporting scaffold in order to facilitate the bone formation process, which also provides the much-needed vascularity.…”

“…Further clinical experimentations suggest the use of In vivo osteogenic properties for the grafting of skeletal muscles. Such experimentation shows that novel strategies can be implemented to facilitate effective bone regeneration [ 19 , 20 , 23 ]. For example, more recently, it has been established that decellularized skeletal muscles (Fig.…”

Mesenchymal stem cells and their relationship to pericytes

“…Pre-clinical protocols associate cells with various biomaterials and biomolecules essential for a good differentiation performance. Gene transfer is used as a tool to stimulate and accelerate the process of tissue specialization (155,156). Clinical trials, on the other hand, are still in early stages and focus on cells with safer and less bold associations such as fibrin glue.…”