Horizontal Alveolar Ridge Splitting and Expansion

When considering placing dental implants in atrophic edentulous sites, there may be inadequate site width and little or no vertical bone loss. Any of several surgical procedures can augment these sites. Extracortical augmentation is done by applying graft material against the cortical bone. This technique expects progenitor cells to migrate outside the bony ridge's confines and form new bone. Another method entails ridge splitting and expansion to create space for osteogenesis and, when possible, implant placement. This may be a better method for horizontal ridge augmentation. The ridge is split, separating the facial and lingual cortices for a complete bone fracture. The patient's osseous cells can then migrate into the created space from the exposed medullary bone to form bone. The technique can be preferably performed flapless so the intact periosteum maintains a blood supply to ensure appropriate healing.

Rib histology after unsuccessful cardiopulmonary resuscitation in infants suffering sudden death from natural causes; implications for injury mechanism and timing

AIMS

To describe whether haemorrhage into the fracture gap, bone marrow, or periosteum, and loss of osteocyte nuclei from infant rib fracture margins, are true markers of vitality or may be seen solely as a consequence of cardiopulmonary resuscitation attempts.

METHODS AND RESULTS

A description is provided of histological findings in sampled rib fractures in a retrospective consecutive series of infants, aged 1 month to 1 year, who suffered sudden death. All had undergone cardiopulmonary resuscitation (CPR) and were investigated by use of skeletal survey, whole body computed tomography (CT), and invasive postmortem (PM). There was no suspicion of child abuse. 15 infants were studied, 9 of whom had anterior/anterolateral rib fractures; slides were available with consent for use in seven. Skeletal survey identified no fractures. CT and PM showed 46 fractures, 27 of which were examined histologically. Marrow cavity haemorrhage> 2 mm in diameter was seen in 55% of fractures; easily identifiable red cells were seen in the fracture gap in 36%, and beneath the periosteum in 36%. Loss of intact osteocytes from lacunae in bone fragments at the fracture margins relative to distant areas was obvious in 50% of fractures.

CONCLUSIONS

Anterior rib fractures, visible on CT and histologically, are common after CPR in infants. Empty lacunae and bleeding into the fracture gap, into the marrow cavity and beneath the periosteum are all frequent in CPR-related infant rib fractures, and should not be used to discriminate between true in-vivo injury and perimortem injury.

How much do we know about the role of osteocytes in different phases of fracture healing? A systematic review

Background

Although emerging studies have provided evidence that osteocytes are actively involved in fracture healing, there is a general lack of a detailed understanding of the mechanistic pathway, cellular events and expression of markers at different phases of healing.

Methods

This systematic review describes the role of osteocytes in fracture healing from early to late phase. Literature search was performed in PubMed and Embase. Original animal and clinical studies with available English full-text were included. Information was retrieved from the selected studies.

Results

A total of 23 articles were selected in this systematic review. Most of the studies investigated changes of various genes and proteins expression patterns related to osteocytes. Several studies have described a constant expression of osteocyte-specific marker genes throughout the fracture healing cascade followed by decline phase with the progress of healing, denoting the important physiological role of the osteocyte and the osteocyte lacuno-canalicular network in fracture healing. The reports of various markers suggested that osteocytes could trigger coordinated bone healing responses from cell death and expression of proinflammatory markers cyclooxygenase-2 and interleukin 6 at early phase of fracture healing. This is followed by the expression of growth factors bone morphogenetic protein-2 and cysteine-rich angiogenic inducer 61 that matched with the neo-angiogenesis, chondrogenesis and callus formation during the intermediate phase. Tightly controlled regulation of osteocyte-specific markers E11/Podoplanin (E11), dentin matrix protein 1 and sclerostin modulate and promote osteogenesis, mineralisation and remodelling across different phases of fracture healing. Stabilised fixation was associated with the finding of higher number of osteocytes with little detectable bone morphogenetic proteins expressions in osteocytes. Sclerostin-antibody treatment was found to result in improvement in bone mass, bone strength and mineralisation.

Conclusion

To further illustrate the function of osteocytes, additional longitudinal studies with appropriate clinically relevant model to study osteoporotic fractures are crucial. Future investigations on the morphological changes of osteocyte lacuno-canalicular network during healing, osteocyte-mediated signalling molecules in the transforming growth factor-beta-Smad3 pathway, perilacunar remodelling, type of fixation and putative biomarkers to monitor fracture healing are highly desirable to bridge the current gaps of knowledge.The translational potential of this article: This systematic review provides an up-to-date chronological overview and highlights the osteocyte-regulated events at gene, protein, cellular and tissue levels throughout the fracture healing cascade, with the hope of informing and developing potential new therapeutic strategies that could improve the timing and quality of fracture healing in the future.