Mechanical analysis of cranial distractor attachment with three different resorbable fixation systems

Distraction osteogenesis (DO) has become increasingly popular to correct craniosynostosis. Disadvantages of DO include the secondary operation needed for device removal and titanium screw related dura injury. To reduce invasiveness of the secondary device removal operation and to overcome titanium-related problems, fixation of the cranial distractor with resorbable materials is a potential alternative. New resorbable fixation methods, such as ultrasound-activated pins (UAPs) or heat-activated pins (HAPs), allow faster attachment on thinner bone than conventional resorbable screws (CRSs) since tapping is not required. However, resorbable materials are designed to be attached with a resorbable plate, not with a titanium distractor. We evaluated the suitability of CRSs, HAPs and UAPs for the cranial distractor fixation in a laboratory setting with a mechanical testing machine. Fracture tests were conducted in two directions with respect to the longitudinal axis; vertical i.e. axial pull-out strength, and horizontal i.e. shear strength. Mean maximum pull-out strength for CRS, HAP and UAP was 48.9 N, 32.5 N and 14.7 N, respectively. Mean maximum shear strength for CRS, HAP and UAP was 40.8 N, 77.9 N and 38.9 N, respectively. According to our in vitro tests, the cranial distractor attachment with four CRSs or six HAPs per footplate would provide sufficient fixation stability. (C) 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.Peer reviewe

The use of patient specific polyetheretherketone implants for reconstruction of maxillofacial deformities

Purpose: The aim of this study was to evaluate polyetheretherketone (PEEK) as a patient-specific implant (PSI) material in maxillofacial reconstructive surgery. Materials and methods: The retrospective study included a cohort of 24 patients who underwent maxillofacial surgery using PEEK PSIs. Each patient underwent preoperative multislice computed tomography (CT) with 0 degrees tilt of gantry. Based on the CT scan, the PEEK PSIs were planned and manufactured using three-dimensional (3D) modeling and computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. All procedures were performed under general anesthesia. Implants were placed intraorally, extraorally or through subciliary, transconjuctival or coronal incisions. Results: In 22 of 24 cases, the PEEK PSI fit well without adjustments. Although the fit to the surrounding bone was perfect in almost all of the cases, the outer contour of the PSI was modified in nine cases before fixation. However, intraoperative implant modification did not affect the infection rate. In two cases, postoperative wound dehiscence and infection needed additional treatment and healed without removal of the implants. Conclusion: The follow-up data in this study showed good outcomes with reliable results for PSI made of PEEK in the maxillofacial region. (C) 2019 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd.Peer reviewe

Force measurements during posterior calvarial vault osteodistraction : A novel measurement method

Posterior calvarial vault osteodistraction (PCVO) has become increasingly popular in the correction of craniosynostosis. When compared to cranioplasty, PCVO offers a shorter, less invasive operation, greater intracranial volume advancement and a lower rate of relapse. In general, distraction protocols are based primarily on clinical observations rather than systematic research. Faster distraction protocols may reduce complications. However, distraction protocols producing higher forces can increase complications. Thus, we need to understand these forces in order to improve distraction protocols and devices. We developed a force measurement method that can be used on PCVO devices. Here, we present preliminary data about the forces developed during PCVO. We measured the forces in four bicoronal craniosynostosis patients during PCVO. We observed a linear-like trend between the force increase and the distraction distance within distraction sessions. We also observed a step-wise force increase between distraction sessions and found that the distraction force relaxed rapidly shortly after the distraction session. The mean maximum pre distraction force for one distracter was 20.4 N, while the mean maximum end-distraction force for one distracter was 57.6 N. Our data suggests that current treatment protocols might be re-evaluated favouring shorter distraction distances and more frequent distraction sessions. (C) 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Of all foods bread is the most noble: Carl von Linné (Carl Linneaus) on bread1

Carl von Linné was interested in dietetics, which in his time covered all aspects of a healthy life. As a utilitarian he understood the importance of private economy and paid attention to bread in many of his publications. Two texts, Ceres noverca arctoum and De pane diaetetico, were wholly devoted to bread and bread-making. Linné classified different types of bread, and described their nutritional value and health-related aspects, as well as milling, baking and storing, in detail. While discussing the food habits of social classes Linné accepted as a fact that the peasants and the poor should eat less tasty bread than the rich. The less palatable bread had, however, many nutritional and health advantages. Linné paid much attention to substitutes for grain to be used in times of famine, an important topic in eighteenth century Sweden. He regarded flour made of pine bark or water arum roots as excellent famine food, was enthusiastic about the new plant, maize, but considered potato only as a poor substitute for grain. Linné and his followers praised bread not only as the core component of diet, but also for its versatile role both in health and in disease

Combining spatial prioritization and expert knowledge facilitates effectiveness of large-scale mire protection process in Finland

Conservation resource allocation involves a complex set of considerations including species, habitats, connectivity, local to global biodiversity objectives, alternative protection and restoration actions, while requiring cost-efficiency and effective implementation. We present a national scale spatial conservation prioritization analysis for complementing the network of protected mires in Finland. We show how spatial prioritization coupled with regional targets and expert knowledge can facilitate structured decision-making. In our application, discussion between experts was structured around the prioritization model enabling integration of quantitative analysis with expert knowledge. The used approach balances requirements of many biodiversity features over large landscapes, while aiming at a cost-effective solution. As a special analytical feature, mire complexes were defined prior to prioritization to form hydrologically functional planning units, including also their drained parts that require restoration for the planning unit to remain or potentially increase in value. This enabled selection of mires where restoration effort is supporting and benefitting from the core mire areas of high conservation value. We found that a key to successful implementation was early on structured co-producing between analysts, mire experts, and decision-makers. This allowed effective multidirectional knowledge transfer and evaluation of trade-offs related to the focal conservation decisions. Quantitative trade-off information was seen especially helpful by the stakeholders to decide how to follow the analysis results. Overall, we illustrate a realistic and applicable spatial conservation prioritization case supporting real world conservation decision-making. The introduced approach can be applied globally to increase effectiveness of large-scale protection and management planning of the diverse wetland ecosystem complexes.Peer reviewe

Climate and land-use change drive population decline in a red-listed plant species

Land-use change is a perennial driver of biodiversity decline. However, climate change may pose novel pressures on species populations, adding to the mixture of anthropogenic threats. Determining the main causes for species decline is important for effective allocation of conservation efforts and for understanding the linkages between biodiversity decline and climate change. Here, we study the impacts of forest management, urbanization, and changes in spring climatic conditions on the presence of a threatened plant species, Pulsatilla patens. In addition, we examine if topographic heterogeneity has supported the persistence of species populations under climatic change starting from 1961. We modelled the effect of land-use and climate change both separately and jointly, finding that both drivers have individual and potentially direct impacts on the persistence of P. patens. This is in agreement with the historic standpoint of land-use change being the main threat for the species, as well as recent findings of the potentially harmful effects of altered climatic conditions in spring, e.g., through late frost damage following earlier emergence of flowers. However, we found no indication that topographic heterogeneity would offer a buffering effect, suggesting that changes in spring climatic conditions form a tangible threat to this species that is not alleviated in the current landscape. As climate change continues, it is likely that the number and intensity of stressors increases for a variety of species, which warrants further attention to the role of climate change and appropriate conservation action