Radiological assessment of bioengineered bone in a muscle flap for reconstruction of a 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 mm615 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 TM |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 (m-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% 615, the mean volume of the radio-opaque areas was 63.4% 620. Areas of a bone density higher than that of the mandibular bone (+35% 625%) 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.

Prefabrication technique by preserving a muscular pedicle from masseter muscle as an in vivo bioreactor for reconstruction of mandibular critical‐sized bone defects in canine models

“…Our results suggest that preserving a muscular pedicle connected to the prefabricated scaffold can significantly enhance new bone formation. However, It has been consistent with Al‐Fotawei et al's study wherein they reconstructed a mandibular defect in rabbit by rotated flap of masseter muscle into which a commercial bone cement in the combination with BMP‐7 and MSCs was injected 11 . They radiographically demonstrated significant enhancement in bone regeneration of their design in comparison with the control site.…”

“…An alternative approach is to develop engineered tissues inside a living bioreactor, the body, while leveraging the self‐regenerative capacity of living body compartments. In vivo bioreactor (IVB) has been introduced as a new prefabrication technique for cell delivery in animals and human models 10–19 . The history of this method can be traced back to the 19th decade, when ectopic bone formation in muscles was reported with application of rhBMP2 12,20 .…”

Effects of the bilayer nano-hydroxyapatite/mineralized collagen-guided bone regeneration membrane on site preservation in dogs

“…Plain X-ray was the most common choice for bone assessment in experimental and clinical research. 49 Our experiment adopted the average length of five referential lines as the alveolar ridge height at baseline within 2, 6, and 12 weeks after surgery, which reduced artificial interference factors due to the influence of different projection, body position. Through X-ray analysis, we found that the mean alveolar ridge height alteration in the 12th weeks of BG group was À1.73 mm, which was in line with the experimental results of À1.69 mm of Xue et al 50 suggesting that the measuring accuracy was sufficient to meet the requirement.…”

A Novel Surgical Approach for the Reconstruction of Critical-Size Mandibular Defects Using Calcium Sulphate/Hydroxyapatite Cement, BMP-7 and Mesenchymal Stem Cells-Histological Assessment

“…Approval was obtained from the UK Home Office under the Animals (Scientific Procedures) Act 1986. Rabbit bone marrow aspiration, rMSCs isolation, culture, characterization and assessment of the cell-cement interaction followed a standard protocol 30 . The cement used in this study was injectable and commercially available (CERAMENT™lSPINE SUPPORT, Bone Support AB, Lund, Sweden) composed of 60% calcium sulphate, 40% hydroxyapatite powder and a liquid phase of water and an opacifier (Iohexol).…”

“…The mandibles were explanted and the surgical sites were examined. Samples were subjected to a comprehensive radiological evaluation 30 and then prepared for histological assessment.…”