Histological Analysis of Bone Repair in Mandibular Body Osteotomy Using Internal Fixation System in Three Different Gaps without Bone Graft in an Animal Model

Abstract

The aim was to analyze histologically the bone repair in a mandibular osteotomy model with different gaps between the segments. Nine male rabbits who underwent osteotomies on the mandibular body were fixed with a 1.5 system plate and no bone graft; group 1 (2 mm gap between segments), group 2 (5 mm gap between segments), and group 3 (8 mm gap between segments) were included. After 8 weeks they were euthanized and the sample was processed for histological analysis. Group 1 showed advanced bone repair with cartilaginous tissue and cancellous bone, showing osteoblasts and type III collagenous fibers. In group 2, a more delayed ossification was observed, with an extensive area of peripheral ossifying cartilage and chondrocytes in greater number at the center of the defect; group 3 showed no evidence of ossification with fibrous tissue, a very low level of chondrocytes, and some bone sequestrate. We can conclude that, in this animal model, 2 or 5 mm gap in the osteotomy could be repaired as bone when fixation is used. The size of the gap is an important factor for the use of bone grafts considering endochondral ossification. This model can be used for graft analysis and related technologies.

Complicated Mandible Fracture Treatment With Xenogenic Bone Graft: A Case Report

“…Currently the mechanisms of bony regeneration are well studied but there are several factors that affect or delay the bony healing process; some are inherent to the patient, others to the fracture itself, and others to the medical management of the patient. The size of the gap or bony defect is an important factor for the use of bone grafts considering endochondral ossification [14,15]. Despite the high efficiency of modern methods of treatment, the bone tissue can be restored in full volume not in all cases.…”

Tratamento cirúrgico de fratura cominutiva de mandíbula envolvendo simplificação com miniplacas: Relato de dois casos

“…As fraturas cominutivas da mandíbula podem evoluir com falhas de estabilidade que podem levar a não união dos fragmentos (Mathog et al, 2000). Nos casos em que a fratura apresenta estabilidade por meio da redução anatômica e compressão entre os fragmentos, o reparo ósseo ocorre por meio de ossificação primária (Olate et al, 2019). Já quando as fraturas mandibulares se apresentam cominutas, consistindo em vários fragmentos, em alguns casos com a presença de gap ou mobilidade, a cicatrização óssea é secundaria (Koshy et al, 2010).…”

Stability as a Key Factor for Bone Repair in Nonunion of Mandibular Osteotomy

“…The results of the recent study published by Olate et al (2019) show the importance of the position and condition of the bone segments when the repair process of a fracture or osteotomy is in the initial stage. The distance between the bone ends established in the different groups defined the type of repair and the evolution of the repair process.…”

“…Failure of segment stability (Madsen et al) and the presence of large spaces between the stabilized fragments (Olate et al 2019) are associated with absence of bone repair and with the presence of inflammatory infiltrate or connective tissue, and such cases develop into nonunion. The aim of this research was to analyze bone repair in a pseudoarthrosis model generated in rabbit mandibles, determining the importance of stabilization of the fragments in bone repair.…”