Biomaterials for craniofacial reconstruction

Biomaterials for reconstruction of bony defects of the skull comprise of osteosynthetic materials applied after osteotomies or traumatic fractures and materials to fill bony defects which result from malformation, trauma or tumor resections. Other applications concern functional augmentations for dental implants or aesthetic augmentations in the facial region

Early bone ingrowth and segmental stability of a trussed titanium cage versus a polyether ether ketone cage in an ovine lumbar interbody fusion model

BACKGROUND CONTEXT: Lumbar interbody fusion is an effective treatment for unstable spinal segments. However, the time needed to establish a solid bony interbody fusion between the two vertebrae may be longer than twelve months after surgery. During this time window, the instrumented spinal segment is assumed to be at increased risk for instability related complications such as cage migration or subsidence. It is hypothesized that the design of new interbody cages that enable direct osseointegration of the cage at the vertebral endplates, without requiring full bony fusion between the two vertebral endplates, might shorten the time window that the instrumented spinal segment is susceptible to failure. PURPOSE: To quantify the bone ingrowth and resulting segmental stability during consolidation of lumbar interbody fusion using two different cage types. STUDY DESIGN: Preclinical ovine model. METHODS: Seven skeletally mature sheep underwent bi-segmental lumbar interbody fusion surgery with one conventional polyether ether ketone (PEEK) cage, and one newly developed trussed titanium (TT) cage. After a postoperative time period of 13 weeks, non-destructive range of motion testing and histological analysis were performed. Additionally, sample specific finite element (FE) analysis was performed to predict the stability of the interbody fusion region alone. RESULTS: Physiological movement of complete spinal motion segments did not reveal significant differences between the segments operated with PEEK and TT cages. The onset of creeping substitution within the cage seemed to be sooner for PEEK cages, which led to significantly higher bone volume over total volume (BV/TV) compared to the TT cages. TT cages showed significantly more direct bone to implant contact (BIC). Although the mean stability of the interbody fusion region alone was not statistically different between the PEEK and TT cages, the variation within the cage types illustrated an all-or-nothing response for the PEEK cages while a more gradual increase in stability was found for the TT cages. CONCLUSIONS: Spinal segments operated with conventional PEEK cages were not different from those operated with newly developed TT cages in terms of segmental stability but did show a different mechanism of bone ingrowth and attachment. Based on the differences in development of bony fusion, we hypothesize that TT cages might facilitate increased early segmental stability by direct osseointegration of the cage at the vertebral endplates without requiring complete bony bridging through the cage. CLINICAL SIGNIFICANCE: Interbody cage type affects the consolidation process of spinal interbody fusion. Whether different consolidation processes of spinal interbody fusion result in clinically significant differences requires further investigation

Early bone ingrowth and segmental stability of a trussed titanium cage versus a polyether ether ketone cage in an ovine lumbar interbody fusion model

BACKGROUND CONTEXT: Lumbar interbody fusion is an effective treatment for unstable spinal segments. However, the time needed to establish a solid bony interbody fusion between the two vertebrae may be longer than twelve months after surgery. During this time window, the instrumented spinal segment is assumed to be at increased risk for instability related complications such as cage migration or subsidence. It is hypothesized that the design of new interbody cages that enable direct osseointegration of the cage at the vertebral endplates, without requiring full bony fusion between the two vertebral endplates, might shorten the time window that the instrumented spinal segment is susceptible to failure. PURPOSE: To quantify the bone ingrowth and resulting segmental stability during consolidation of lumbar interbody fusion using two different cage types. STUDY DESIGN: Preclinical ovine model. METHODS: Seven skeletally mature sheep underwent bi-segmental lumbar interbody fusion surgery with one conventional polyether ether ketone (PEEK) cage, and one newly developed trussed titanium (TT) cage. After a postoperative time period of 13 weeks, non-destructive range of motion testing and histological analysis were performed. Additionally, sample specific finite element (FE) analysis was performed to predict the stability of the interbody fusion region alone. RESULTS: Physiological movement of complete spinal motion segments did not reveal significant differences between the segments operated with PEEK and TT cages. The onset of creeping substitution within the cage seemed to be sooner for PEEK cages, which led to significantly higher bone volume over total volume (BV/TV) compared to the TT cages. TT cages showed significantly more direct bone to implant contact (BIC). Although the mean stability of the interbody fusion region alone was not statistically different between the PEEK and TT cages, the variation within the cage types illustrated an all-or-nothing response for the PEEK cages while a more gradual increase in stability was found for the TT cages. CONCLUSIONS: Spinal segments operated with conventional PEEK cages were not different from those operated with newly developed TT cages in terms of segmental stability but did show a different mechanism of bone ingrowth and attachment. Based on the differences in development of bony fusion, we hypothesize that TT cages might facilitate increased early segmental stability by direct osseointegration of the cage at the vertebral endplates without requiring complete bony bridging through the cage. CLINICAL SIGNIFICANCE: Interbody cage type affects the consolidation process of spinal interbody fusion. Whether different consolidation processes of spinal interbody fusion result in clinically significant differences requires further investigation

High Mortality of COVID-19 Early after Allogeneic Stem Cell Transplantation: A Retrospective Multicenter Analysis on Behalf of the German Cooperative Transplant Study Group

Recipients of allogeneic stem cell transplantation (alloSCT) are at high risk for contracting infectious diseases with high morbidity and mortality. Coronavirus disease 2019 (COVID-19) is a viral respiratory disease that can lead to severe pneumonia and acute respiratory distress syndrome, with a potentially fatal outcome. In this retrospective study conducted on behalf of the German Cooperative Transplant Study Group, we aimed to analyze risk factors, disease course, and outcomes of COVID-19 in patients who underwent alloSCT. AlloSCT recipients who became infected with SARS-CoV-2 at German and Austrian transplant centers between February 2020 and July 2021 were included. Classification of COVID-19 severity into mild, moderate-severe, or critical disease and division of the course of the pandemic into 4 phases were done according to the German Robert Koch Institute. The main endpoint was overall mortality at the end of follow-up. We further analyzed the need for treatment in an intensive care unit (ICU) and the severity of disease. Risk factors were evaluated using univariate and multivariate analyses, and survival analysis was performed using Kaplan-Meier method. The study cohort comprised 130 patients from 14 transplant centers, with a median age at diagnosis of COVID-19 of 59 years (range, 20 to 81 years) and a median interval between alloSCT and COVID-19 of 787 days (range, 19 to 8138 days). The most common underlying diseases were acute myeloid leukemia (45.4%) and lymphoma (10.8%). The majority of patients (84.9%) were infected in the later phases of the pandemic; 20.8% had moderate-severe disease, 12.3% had critical disease, and 19.2% were treated in an ICU. After a median follow-up of 127 days, overall mortality was 16.2%, 52.0% among patients treated in an ICU. Risk factors for mortality in multivariate analysis were active disease (odds ratio [OR], 4.46), infection with SARS-CoV-2 60 years (OR, 5.39), and ongoing immunosuppression with cyclosporine (OR, 8.55). Risk factors for developing moderate-severe or critical disease were concurrent immunosuppression (OR, 4.06) and age >40 years (OR, 4.08). Patients after alloSCT exhibit a substantially increased mortality risk after COVID-19 infection compared with the normal population, without considerable improvement over the course of the pandemic. Risk factors include age, early infection post-alloSCT, and active immunosuppression. Further studies are needed to improve prevention and treatment in this high-risk patient group. (c) 2022 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/

High Mortality of COVID-19 Early after Allogeneic Stem Cell Transplantation: A Retrospective Multicenter Analysis on Behalf of the German Cooperative Transplant Study Group

Recipients of allogeneic stem cell transplantation (alloSCT) are at high risk for contracting infectious diseases with high morbidity and mortality. Coronavirus disease 2019 (COVID-19) is a viral respiratory disease that can lead to severe pneumonia and acute respiratory distress syndrome, with a potentially fatal outcome. In this retrospective study conducted on behalf of the German Cooperative Transplant Study Group, we aimed to analyze risk factors, disease course, and outcomes of COVID-19 in patients who underwent alloSCT. AlloSCT recipients who became infected with SARS-CoV-2 at German and Austrian transplant centers between February 2020 and July 2021 were included. Classification of COVID-19 severity into mild, moderate-severe, or critical disease and division of the course of the pandemic into 4 phases were done according to the German Robert Koch Institute. The main endpoint was overall mortality at the end of follow-up. We further analyzed the need for treatment in an intensive care unit (ICU) and the severity of disease. Risk factors were evaluated using univariate and multivariate analyses, and survival analysis was performed using Kaplan-Meier method. The study cohort comprised 130 patients from 14 transplant centers, with a median age at diagnosis of COVID-19 of 59 years (range, 20 to 81 years) and a median interval between alloSCT and COVID-19 of 787 days (range, 19 to 8138 days). The most common underlying diseases were acute myeloid leukemia (45.4%) and lymphoma (10.8%). The majority of patients (84.9%) were infected in the later phases of the pandemic; 20.8% had moderate-severe disease, 12.3% had critical disease, and 19.2% were treated in an ICU. After a median follow-up of 127 days, overall mortality was 16.2%, 52.0% among patients treated in an ICU. Risk factors for mortality in multivariate analysis were active disease (odds ratio [OR], 4.46), infection with SARS-CoV-2 60 years (OR, 5.39), and ongoing immunosuppression with cyclosporine (OR, 8.55). Risk factors for developing moderate-severe or critical disease were concurrent immunosuppression (OR, 4.06) and age >40 years (OR, 4.08). Patients after alloSCT exhibit a substantially increased mortality risk after COVID-19 infection compared with the normal population, without considerable improvement over the course of the pandemic. Risk factors include age, early infection post-alloSCT, and active immunosuppression. Further studies are needed to improve prevention and treatment in this high-risk patient group. (c) 2022 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/

“Primeval forest relict beetles” of Central Europe : a set of 168 umbrella species for the protection of primeval forest remnants

Identification of forest stands with priority for the conservation of biodiversity is of particular importance in landscapes with a long cultural and agricultural history, such as Central Europe. A group of species with a high indicator value for the naturalness of forest ecosystems are saproxylic insects. Some of these species, especially within the order Coleoptera, have been described as primeval forests relicts. Here, we compiled a list of 168 “primeval forest relict species” of saproxylic beetles based on expert knowledge. These species can serve as focal and umbrella species for forest conservation in Central Europe. They were selected because of their dependence on the continuous presence of primeval forest habitat features, such as over-mature trees, high amounts of dead wood, and dead wood diversity, as well as their absence in managed Central European forests. These primeval forest relict species showed a moderately strong clumping pattern within the phylogeny of beetles, as indicated by phylogenetic signal testing using the D-statistic. When we controlled for phylogenetic relatedness, an ordinal linear model revealed that large body size and preference for dead wood and trees of large diameter are the main characteristics of these species. This list of species can be used to identify forest stands of conservation value throughout Central Europe, to prioritize conservation and to raise public awareness for conservation issues related to primeval forests