Ultrasound stimulation of mandibular bone defect healing

The conclusions of the experimental work presented in this thesis are: 1. Low intensity pulsed ultrasound is not effective in stimulating bone growth into a rat mandibular defect, either with or without the use of osteoconductive membranes. 2. Low intensity pulsed ultrasound does not seem to have an effect on the early bone formation in the vertically distracted, severely resorbed mandible. This thesis focused on a small area in the field of ultrasound and bone healing that had not been explored before. The animal experimental work indicates that ultrasound does not stimulate mandibular bone defect healing with or without the use of osteoconductive membranes in healthy animals. This may be related to the ultrasound field variables used, to an optimal healing tendency of the head and neck region, or to limitations of the animal model. To reveal which of these possibilities is the most plausible, additional research is needed. For now, it is not recommendable to apply ultrasound in maxillofacial surgery to stimulate bone defect healing. In situations where mechanical loading or blood perfusion is limited, as for example in the case of mandibular fractures or osteoradionecrosis, ultrasound might have an effect. More importantly, unravelling the mechanism of action as to how ultrasound stimulates bone healing in certain cases may eventually predict if, and if so, when, ultrasound may be of value in maxillofacial surgery.

Incorporation of anterior iliac crest or calvarial bone grafts in reconstructed atrophied maxillae:A randomized clinical trial with histomorphometric and micro-CT analyses

BACKGROUND: Autologous bone grafts have been applied successfully to severely atrophied maxilla via a preimplant procedure. Differences in graft incorporation at the microscopic level can be the decisive factor in the choice between anterior iliac crest and calvarial bone. PURPOSE: To compare conversion of anterior iliac crest bone and calvarial bone 4 months after grafting of the edentulous maxilla. MATERIALS AND METHODS: Twenty consecutive patients were randomly assigned to either anterior iliac crest (n = 10) or calvarial (n = 10) bone harvesting to reconstruct their atrophied maxillae. Biopsies were taken from both fresh bone grafts and reconstructed maxillae after 4 months healing, at time of implant placement. Micro-CT, histomorphometric and histological analyses were performed. RESULTS: Micro-CT analysis revealed that both the anterior iliac crest and calvarial bone grafts retained their volume and bone mass after being incorporated in the maxilla, but with a favor for calvarial bone grafts: calvarial bone grafts had a higher mineral density before and after incorporation. Both bone grafts types were well incorporated after 4 months of healing with preservation of bone volume and mineral density. Although the fresh bone biopsies were similar histomorphometrically, after 4 months of graft incorporation, the osteoid percentage and osteocyte count remained higher in the anterior iliac crest bone whereas the percentage of bone was higher in the calvarial bone grafts compared to the anterior iliac crest bone grafts. CONCLUSIONS: Both donor sites, that is, anterior iliac crest and calvarial bone, are well suited to provide a reliable and stable basis for implant placement 4 months after grafting with mineral density, porosity, and resorption rate in favor of calvarial bone grafts

Harvesting anterior iliac crest or calvarial bone grafts to augment severely resorbed edentulous jaws:a systematic review and meta-analysis of patient-reported outcomes

The aim of this systematic review was to compare patient-reported outcomes after harvesting calvarial or anterior iliac crest bone grafts to repair severe jaw defects and enable implant placement. The MEDLINE, Embase, Cochrane Central Register of Controlled Trials databases, and OpenGrey were searched for studies on patient satisfaction, pain, disturbances in daily functioning, sensory alterations, donor site aesthetics, and complication rates. Of the 1946 articles identified, 43 reporting 40 studies fulfilled the inclusion criteria; the studies were one randomized controlled clinical trial, one retrospective controlled clinical trial, and 23 prospective and 15 retrospective cohort studies. A meta-analysis of two studies (74 patients) showed no difference in satisfaction (mean difference (MD) − 0.13, 95% confidence interval (CI) − 1.17 to 0.92; P = 0.813) or postoperative pain (directly postoperative: MD −2.32, 95% CI −5.20 to 0.55, P = 0.113; late postoperative: MD −0.01, 95% CI −0.14 to 0.11, P = 0.825) between donor sites. However, the level of evidence is limited, due to the retrospective, non-randomized design of one study. Postoperative gait disturbances were highly prevalent among the anterior iliac crest patients (28–100% after 1 week). The incidence rates of sensory disturbances and other complications were low, and the donor site aesthetic outcomes were favourable for both graft types. To conclude, harvesting bone grafts from the calvarium or anterior iliac crest to augment the severely resorbed edentulous jaw results in similar patient satisfaction. However, the findings for postoperative pain and disturbances in daily living suggest a trend in favour of calvarial bone grafts if harvested using an adjusted technique

Histomorphometric and micro-CT analyses of calvarial bone grafts used to reconstruct the extremely atrophied maxilla

Background Calvarial bone grafts are successful in the reconstruction of the severely atrophied maxilla as a pre-implant procedure. However, not much is known about graft incorporation at the microscopic level. Purpose This study aimed to assess calvarial bone conversion 4 months after being grafted in the edentulous maxillary bone. Materials and methods In 13 patients (age:65.3 +/- 8.7 years) the atrophic maxilla was reconstructed with autologous calvarial bone. Biopsies were taken from fresh calvarial bone grafts and from the reconstructed maxillae after 4 months of healing. Micro-CT, histomorphometric, and histological analysis were performed. From three patients biopsies were obtained after 9, 11, or 45 months. Results The micro-CT analysis revealed that in the maxilla the calvarial bone was well preserved even after 45 months. Histology showed progressive incorporation of grafted bone within a maxillary bone. Osteoid and osteocytes were present in all biopsies indicating new bone formation and vital bone. Histomorphometrically, the percentage of grafted bone volume over total volume decreased from 79.8% (IQR78.7-83.3) in fresh calvarial grafts to 59.3% (IQR44.8-64.6) in healed grafts. The biopsies were taken after 9, 11, and 45 months showed similar values. Conclusions Calvarial bone grafts result in stable and viable bone, good incorporation into native maxillary bone, and a minor decrease in bone volume after healing. Consequently, they provide a solid base for implant placement in severely atrophied edentulous maxillary bone

Effect of thrombin peptide 508 (TP508) on bone healing during distraction osteogenesis in rabbit tibia

Thrombin-related peptide 508 (TP508) accelerates bone regeneration during distraction osteogenesis (DO). We have examined the effect of TP508 on bone regeneration during DO by immunolocalization of Runx2 protein, a marker of osteoblast differentiation, and of osteopontin (OPN) and bone sialoprotein (BSP), two late markers of the osteoblast lineage. Distraction was performed in tibiae of rabbits over a period of 6 days. TP508 (30 or 300 μg) or vehicle was injected into the distraction gap at the beginning and end of the distraction period. Two weeks after active distraction, tissue samples were harvested and processed for immunohistochemical analysis. We also tested the in vitro effect of TP508 on Runx2 mRNA expression in osteoblast-like (MC3T3-E1) cells by polymerase chain reaction analysis. Runx2 and OPN protein were observed in preosteoblasts, osteoblasts, osteocytes of newly formed bone, blood vessel cells and many fibroblast-like cells of the soft connective tissue. Immunostaining for BSP was more restricted to osteoblasts and osteocytes. Significantly more Runx2- and OPN-expressing cells were seen in the group treated with 300 μg TP508 than in the control group injected with saline or with 30 μg TP508. However, TP508 failed to increase Runx2 mRNA levels significantly in MC3T3-E1 cells after 2–3 days of exposure. Our data suggest that TP508 enhances bone regeneration during DO by increasing the proportion of cells of the osteoblastic lineage. Clinically, TP508 may shorten the healing time during DO; this might be of benefit when bone regeneration is slow

Open reduction and internal fixation of combined fourth and fifth carpometacarpal [fracture] dislocations

Background: Traditionally, combined fourth and fifth carpometacarpal fracture dislocations are treated conservatively or by means of Kirschner wire after closed reduction. Since 1983, unstable dislocations have been treated with open reduction and screw fixation or with a temporary plate that bridges the fourth carpometacarpal (CMC) joint to maintain anatomical reduction. Methods: In a retrospective study, we evaluated the results of this surgical approach in a group of 11 patients and another group of 4 conservatively treated patients. Results: Eleven patients were treated by means of open reduction and rigid screw fixation (n = 6) or plate bridging of the fourth CMC joint (n = 5). Reduction and fixation of the fourth CMC joint always led to spontaneous anatomical reduction of the fifth CMC joint. At long-term follow-up, nine of these patients had full recovery of their hand function without any complaints. Conclusion: Open reduction and internal fixation of unstable ulnar CMC dislocations produced excellent results