Comparison of Vascularized Osteoperiosteal Femur Flaps and Nonvascularized Femur Grafts for Reconstruction of Mandibular Defects: An Experimental Study

PubMedID: 19446201Purpose: The aim of this study was to compare the vascularized osteoperiosteal femur flaps (VFFs) and the nonvascularized femur grafts (NVFGs) for reconstruction of the mandibular defects of pigs. Materials and Methods: Eight adult domestic pigs were used. The defects created in the mandibular angle were reconstructed with VFFs in 4 pigs (group 1) and NVFGs in the other 4 pigs (group 2). All the pigs were killed after 3 months of healing. Undecalcified and decalcified sections were prepared for histomorphometric analysis and histologic examination. Radiodensitometric absorptiometry was used to assess the differences in bone mineral density between the 2 groups. Results: The bone volume to the total measured volume, trabecular thickness, and trabecular number were significantly greater in the VFF group than in the NVFG group (P < .05). However, the trabecular separation was significantly lower in the VFF group than the NVFG group (P = .029). Although the VFF group had a greater bone mineral density value than the NVFG group, the difference was not statistically significant (P = .057). In histologic examination, the viability of bone in the VFF group, enchondral bone healing, and lamellar bone formation in the NVFG group were apparent. Conclusions: The results of this study suggest that NVFGs have a greater bone resorption rate than do VFFs. Furthermore, the histomorphometric results imply that reconstruction of the mandibular defects with vascularized osteoperiosteal femur flaps will provide greater strength. © 2009 American Association of Oral and Maxillofacial Surgeons

Comparative study of the osseous healing process following three different techniques of bone augmentation in the mandible: An experimental study

PubMedID: 25091894The aim of this study was to evaluate the osseointegration of three different bone grafting techniques. Forty-eight mature New Zealand rabbits were divided randomly into three groups of 16 each. Horizontal augmentation was performed on the corpus of the mandible using three different techniques: free bone graft (FBG), free periosteal bone graft (PBG), pedicled bone flap (BF). The animals were sacrificed at postoperative weeks 1, 3, or 8. Specimens were decalcified for histological examination, and histomorphometric measurements were performed. The histological evaluation demonstrated bony fusion between the grafts and the augmented mandibular bone after 8 weeks in all groups. At week 8, the bone volume was significantly greater in the BF group than in the FBG (P < 0.001) and PBG (P = 0.001) groups, and also the trabecular thickness was significantly greater than in the FBG (P = 0.015) and PBG (P = 0.015) groups. Trabecular separation was significantly lower in the BF group than in the FBG group at week 8 (P = 0.015). BF demonstrated greater osseous healing capacity compared to FBG and PBG. The preserved vascularization in BF improves the bone quality in mandibular bone augmentations. © 2014 International Association of Oral and Maxillofacial Surgeons

Arterialized venous bone flaps: An experimental investigation

PubMedID: 27558705In arterialized venous flaps (AVFs) the venous network is used to revascularize the flap. While the feasibility of AVFs in soft tissues has been reported there is no study on osseous AVFs. In this study we aim to assess the flap survival of osseous AVFs in a pig model. Medial femoral condyle flaps were elevated in 18 pigs. Three groups were created: AVF (n = 6), conventional arterial flap (cAF, n = 6) and bone graft (BG, n = 6). The AVFs were created by anastomosis of genicular artery with one vena comitans while leaving one efferent vein for drainage. After 6 months the specimens were harvested. The histology and histomorphometry of of the bone in cAF and AVF was significantly superior to bone grafts with a higher bone volume in AVFs (p = 0.01). This study demonstrates that osseous free flaps may be supported and survive using the technique of arterialization of the venous network. The concept of AVFs in osseous flaps may be feasible for revascularization of free flaps with an inadequate artery but well developed veins. Further experimental and clinical studies are needed to assess the feasibility of clinical use of arterialized venous bone flaps. © The Author(s) 2016

Third-party policing: A theoretical analysis of an emerging trend

“Third-party policing” describes police efforts to persuade or coerce nonoffending persons to take actions which are outside the scope of their routine activities, and which are designed to indirectly minimize disorder caused by other persons or to reduce the possibility that crime may occur. The practice applies formal, noncriminal controls found in civil law as coercive tools against an intermediate class of nonoffending persons who are thought to have some power over offenders' primary environments. The police use coercion to create place guardianship that previously was absent, so as to decrease opportunities for crime and disorder. We link the theoretical bases of crime prevention to the theory of third-party policing, and examine gaps in traditional policing that have led to a formalization of policing through third parties. We examine third-party policing in two location-specific programs: the drug-abatement Beat Health Program in Oakland and the problem-solving RECAP Unit in Minneapolis. We conclude by discussing the potential ramifications of the third-party trend

Low-Grade and High-Grade Invasive Ductal Carcinomas of the Breast Follow Divergent routes of Progression

Low-grade invasive ductal carcinoma is almost diploid, and has frequent losses of chromosome 16q, which is shared by other precancerous lesions of the mammary gland such as flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH), and low-nuclear grade ductal carcinoma in situ (DCIS). The genetic alterations accumulate in a stepwise fashion as the precancerous lesions progress to invasve ductal carcinoma. This supports the linear progression model of breast cancer from FEA, through ADH, to low-nuclear grade DCIS as non-obligate early events in low-grade IDC evolution. In contrast, high-grade carcinoma tends to aneuploidy with complex genetic alterations—most importantly, frequent gains at chromosome 16q. Frequent losses at chromosome 16q in low-grade IDC and gains in the same arm of the same chromosome in high-grade IDC imply that these lesions are two end outcomes of different disease processes and that they do not lie in the same continuum of a process. Therefore, low-grade and high-grade IDC are two distinct diseases with a divergent route of progression