Volumetric evaluation of osteotomy gap following mandibular bilateral sagittal split osteotomy using a novel semi-automated approach: a pilot study.

OBJECTIVES: To establish an analysis pipeline for the volumetric evaluation of the osteotomy site after bilateral sagittal split osteotomy (BSSO). PATIENTS AND METHODS: Cone-beam computed tomography (CBCT) was performed before, directly after BSSO, and 6-12 months after surgery. Image segmentations of each osteotomy gap data set were performed manually by four physicians and were compared to a semi-automatic segmentation approach. RESULTS: Five patients with a total of ten osteotomy gaps were included. The mean interclass correlation coefficient (ICC) of individual patients was 0.782 and the standard deviation 0.080 when using the manual segmentation approach. However, the mean ICC of the evaluation of anatomical sites and time points separately was 0.214, suggesting a large range of deviation within the manual segmentation of each rater. The standard deviation was 0.355, further highlighting the extent of the variation. In contrast, the semi-automatic approach had a mean ICC of 0.491 and a standard deviation of 0.365, which suggests a relatively higher agreement among the operators compared to the manual segmentation approach. Furthermore, the volume of the osteotomy gap in the semi-automatic approach showed the same tendency in every site as the manual segmentation approach, but with less deviation. CONCLUSION: The semi-automatic approach developed in the present study proved to be valid as a standardised method with high repeatability. Such image analysis methods could help to quantify the progression of bone healing after BSSO and beyond, eventually facilitating the earlier identification of patients with retarded healing.

Prognostic value of lymph node involvement in oral squamous cell carcinoma.

OBJECTIVES: Different parameters have been identified in patients with oral squamous cell carcinomas (OSCC) that have a serious impact on survival, including residual tumour and extracapsular spread. Moreover, other factors, including the lymph node ratio (LNR) and lymph node yield (LNY), have been suggested as prognostic markers. MATERIAL AND METHODS: This retrospective study included patients diagnosed with OSCC and cervical lymph node metastases during the years 2010-2020. Patients' records were evaluated regarding lymph node status, final therapy regime, tumour recurrence, time to death, tumour association with death, disease-free survival (DSF), and overall survival (OS). RESULTS: In 242 patients with a mean age of 63.57 ± 11.24 years, treated either by selective neck dissection (SND; n = 70) or by modified radical neck dissection (MRND; n = 172), 5772 lymph nodes were detected. The LNR and LNY were identified as independent risk factors in OS and DFS. The optimal cut-off point for the LNY was ≥ 17 lymph nodes in the SND and ≥ 27 lymph nodes in the MRND group. The metastatic lymph node clearance (MLNC) was established as a score to relate the LNR and LNY to the extent of lymph node removal. Survival analysis showed statistically significant differences among score levels. CONCLUSIONS: As information about the extent of nodal dissection is excluded from LNR and LNY, we propose the use of a new scoring system comprising individual cut-off values for LNY and LNR with regard to the extent of neck dissection. CLINICAL RELEVANCE: MLNC might help to identify high-risk OSCC patients with metastatic lymph nodes.

Modified McLaughlin's Dynamic Muscle Support in the 21st Century? A Retrospective Study With a Prospective Follow-Up Analysis for Patients With Long Standing Facial Paralysis.

INTRODUCTION: Facial nerve paralysis can dramatically affect the life of a patient as it leads to significant alterations of the facial symmetry and functional limitations. Various methods exist including free neuromuscular flaps to reanimate patients suffering from uni- or even bilateral facial nerve paralysis. The more than 60-year-old technique described by McLaughlin continues to offer an alternative with distinct advantages for the individual patient. The present study aimed to evaluate clinical outcome and satisfaction of patients treated with a modified McLaughlin's Dynamic Muscle Support. MATERIALS AND METHODS: A total of 13 patients (mean age of 58.4 years) who received a modified McLaughlin's Dynamic Muscle Support due to uni- or bilateral long-standing facial paralysis were included. Medical records were reviewed retrospectively, and patients were contacted for additional follow-up. Patients who agreed to participate in the follow-up study were asked to answer a self-developed questionnaire. RESULTS: In all patients, a rehabilitation of facial symmetry with an improvement of the mimic expression could be achieved. Mean length of inpatient stay was 6.5 days and average duration of surgery was 121 minutes. No surgical site infection occurred. Mean follow-up was 23 months. Most of the patients were fully satisfied with the result and could experience functional and esthetic improvement.Patients who participated in the prospective follow-up study were very satisfied with the esthetic result and functional outcome. CONCLUSIONS: Even in times of advanced microsurgical techniques, McLaughlin's Dynamic Muscle Support appears to be a good alternative for the successful treatment of long-standing facial paralysis.

Following in the footsteps of Hippocrates-interrelation between the incidence of odontogenic abscess and meteorological parameters.

OBJECTIVES: Although many physicians in daily practice assume a connection between odontogenic infections and meteorological parameters, this has not yet been scientifically proven. Therefore, the aim of the present study was to evaluate the incidence of odontogenic abscess (OA) in relation to outdoor temperature and atmospheric pressure. PATIENTS AND METHODS: An analysis of patients with an odontogenic abscess who presented at the emergency department within a period of 24 months was performed. Only patients who had not received surgical or antibiotic treatment prior to presentation and who lived in Berlin/Brandenburg were included. The OA incidence was correlated with the mean/maximum outdoor temperature and atmospheric pressure starting from 14 days before presentation. The statistical analysis was carried out using Poisson regression models with OA incidence as dependent and meteorological parameters as independent variables. RESULTS: A total of 535 patients (mean age 39.4 years; range 1 to 95 years) with 538 cases were included. Of these, 227 were hospitalized. The most frequent diagnosis was a canine fossa abscess. A significant association between mean (p = 0.0153) and maximum temperature (p = 0.008) on the day of the presentation and abscess incidence was observed. Furthermore, a significant correlation between OA incidence and maximum temperature 2 days before presentation was found (p = 0.034). The deviation of the mean temperature on the day of the presentation from the monthly mean temperature had a significant influence (p = 0.021) on the incidence of OA. In contrast to temperature, atmospheric pressure had no significant influence on the incidence of OA. CONCLUSION: This study supports a relationship between the incidence of odontogenic abscess and outdoor temperature, but not atmospheric pressure. A significantly higher frequency of patients with an OA presented at our emergency department on days with (comparably) low and high outdoor temperatures. Furthermore, a significant correlation between incidence and maximum temperature 2 days before presentation was found. CLINICAL RELEVANCE: The treatment of odontogenic infections has become a significant economic burden to public health care facilities. The results of this study may help to adapt the numbers of doctors/dentists on duty in relation to different weather conditions. In any case, it is an impetus to think outside the box.

[Frequency and management of complex facial fractures-an oral and maxillofacial surgical assessment]. / Häufigkeit und Management von Gesichtsschädelfrakturen ­ eine MKG-chirurgische Einschätzung.

INTRODUCTION: The treatment of facial fractures is an integral part of the oral and maxillofacial surgical treatment spectrum. In the case of complex fractures that involve multiple levels of the facial skeleton associated with severe concomitant injuries, an individual and interdisciplinary treatment approach is needed, which requires the infrastructure of a national trauma center. OBJECTIVE: The aim of this study was to analyze the incidence and management of patients with complex facial fractures and considering the concomitant injury pattern. MATERIAL AND METHODS: A retrospective analysis of patients with complex facial fractures during the years 2009-2015 admitted to the emergency surgical department of a national trauma center was carried out. The identification of appropriate patient cases was based on the International Statistical Classification of Diseases and Related Health Problems (ICD) coding of electronic patient data. Only patients with at least a combination of mandibular and midfacial fractures (2-level fractures) were considered. Patients with mainly dentoalveolar fractures and simple nasal bone fractures were not included. The evaluation of the electronic medical records included the etiology, fracture pattern, associated severe injuries on the basis of the injury severity score (ISS), treatment regimen as well as the length of the hospital stay. RESULTS: In the 7­year study period, 3382 patients were identified with facial fractures. Of these, 128 patients (3.78%) presented with a complex fracture pattern with a combination of mandibular fractures and fractures of the midface. The majority of these patients (n = 92) had less severe concomitant injuries (ISS ≤ 16), while 36 patients showed severe concomitant injuries (ISS > 16). The incidence of a 3-level fracture involving the mandible, midface and anterior skull base was only 0.47% and could be detected in 16 patients, of which 10 were classified as polytrauma (ISS > 16). CONCLUSION: The incidence of complex fractures of the facial skeleton was comparatively low with almost 4%. More than one in four patients with complex injury patterns of the facial skeleton exhibited severe concomitant life-threatening injuries, necessitating an interdisciplinary management with the specialized infrastructure of a nationwide trauma center.

Clinical outcome after orbital floor fracture reduction with special regard to patient's satisfaction.

PURPOSE: Primary reconstruction via transconjunctival approach is a standardized treatment option for orbital floor fractures. The aim of this study was to compare the findings of specific ophthalmologic assessment with the patient's complaints after fracture reduction. METHODS: A retrospective medical chart analysis was performed on patients who had undergone transconjunctival orbital floor fracture reduction for fracture therapy with resorbable foil (ethisorb sheet or polydioxanone foil). A follow-up assessment including ophthalmological evaluation regarding visual acuity (eye chart projector), binocular visual field screening (Bagolini striated glasses test) and diplopia (cover test, Hess screen test) was conducted. Additionally, a questionnaire was performed to assess patients' satisfaction. RESULTS: A total of 53 patients with a mean follow-up of 23 months (ranging from 11 to 72) after surgical therapy were included. Diplopia was present preoperatively in 23 (43.4%) and reduced in follow-up examination (n = 12, 22.6%). Limitations in ocular motility reduced from 37.7% to 7.5%. The questionnaire about the patient's satisfaction revealed excellent outcomes in relation to the functional and esthetical parameters. CONCLUSION: Transconjunctival approach is a safe approach for orbital fracture therapy. Postoperative diplopia is nearly never perceptible for the individual and differs to pathologic findings in the ophthalmic assessment.

Dendritic cells tip the balance towards induction of regulatory T cells upon priming in experimental autoimmune encephalomyelitis.

Counter-balancing regulatory mechanisms, such as the induction of regulatory T cells (Treg), limit the effects of autoimmune attack in neuroinflammation. However, the role of dendritic cells (DCs) as the most powerful antigen-presenting cells, which are intriguing therapeutic targets in this context, is not fully understood. Here, we demonstrate that conditional ablation of DCs during the priming phase of myelin-specific T cells in experimental autoimmune encephalomyelitis (EAE) selectively aborts inducible Treg (iTreg) induction, whereas generation of T helper (Th)1/17 cells is unaltered. DCs facilitate iTreg induction by creating a milieu with high levels of interleukin (IL)-2 due to a strong proliferative response. In the absence of DCs, B220+ B cells take over priming of Th17 cells in the place of antigen-presenting cells (APCs), but not the induction of iTreg, thus leading to unregulated, severe autoimmunity.

Treatment of Wound Healing Disorders of Radial Forearm Free Flap Donor Sites Using Cold Atmospheric Plasma: A Proof of Concept.

PURPOSE: The treatment of wound healing disturbances of the radial forearm free flap donor site after reconstructive surgery is typically long and burdensome and often requires additional surgery. Cold atmospheric plasma is a promising approach to overcome these impairments. The aim of this proof of concept study was to evaluate the clinical outcome of plasma irradiation in patients with wound healing disorders with exposed brachial tendons of the radial forearm. PATIENTS AND METHODS: Four patients (mean age 64.2 years, range 44 to 80) who had undergone radial forearm free flap procedures and developed wound healing disturbance leading to exposed flexor tendons were included in the present prospective case series. In addition to routine wound care, all sites were irradiated with cold atmospheric plasma. The primary outcome variable was complete wound closure. RESULTS: In all patients, complete wound repair in terms of the absence of tendon exposure was observed within a mean treatment time of 10.1 weeks (range 4.9 to 16). No undesirable side effects were observed, and no inflammation or infection occurred. CONCLUSIONS: Cold atmospheric plasma could offer a reliable conservative treatment option for complicated wound healing disturbances. This was exemplarily shown in the case of radial forearm free flap donor site morbidity with exposed flexor tendons in the present study.

Age-Related Changes of the Orolabial Region in Caucasian Women: An Anthropometric Analysis.

PURPOSE: Anthropometric data can provide valuable support for the attending physician in planning surgical and nonsurgical esthetic procedures with regard to a patient's age. The purpose of the present study was to identify age-related orolabial changes in younger and older Caucasian women. MATERIALS AND METHODS: In the present cross-sectional study, anthropometric landmarks were identified using indirect anthropometry (2-dimensional photometry) in younger (≤35 yr) and older (≥50 yr) Caucasian women to analyze age-related parameters and proportions of the orolabial region, especially of the lower and upper lip vermilion areas. The Mann-Whitney U test was applied to compare the results between the younger and older populations. RESULTS: The study population consisted of 45 women. The cohort was divided into a younger population (24 participants; mean age, 27.4 yr) and an older population (21 participants; mean age, 58 yr) to evaluate age-related differences. Increases of upper lip height, cutaneous height of the upper lip, and cutaneous height of the lower lip were observed in older women. In contrast, the vermilion height of the lower lip decreased significantly with increasing age. CONCLUSION: These results show changes of the orolabial region occur in Caucasian women with increasing age. The statistically relevant decrease of the vermilion height of the lower lip should be given particular attention for (age-appropriate) diagnostic, esthetic, and prosthetic treatment planning.

Severe tooth loss after root damage caused by predrilled intermaxillary fixation screw: a case report.

Intermaxillary fixation (IMF) with screws is routinely used as a conservative therapy or to obtain normal occlusion during the surgical procedure of open reduction and internal fixation for treating mandibular fractures. The risk of iatrogenic dental damage caused by interdental drilling is widely known. Several side effects are described, including loss of response to pulp sensibility testing, root fracture, and, loss of the tooth. This is a case report about a young man who had undergone temporary IMF treatment with a single proven root damage. The patient did not appear for follow-up but he presented 5 years afterward with local purulent osteomyelitis concerning the affected and the adjacent teeth. Osteotomy and extraction of two premolars and one molar were necessary for rehabilitation. This case report illustrates the importance of careful use of predrilled IMF screws and the necessity of frequent follow-ups in cases of proven tooth root damage due to IMF treatment.

Diagnostic pitfalls in pediatric orbital entrapment fractures.

Prompt diagnosis and management of orbital entrapment fractures in the pediatric patient have been advocated. This retrospective study analyzed a cohort of orbital entrapment fractures in pediatric patients with regard to diagnostic pitfalls, treatment and outcomes in a Level I trauma center in Germany. Based on medical records and radiological imaging, patients under the age of 18 years who presented with orbital fractures during 2009-2021 were analyzed. Overall, 125 patients presented with orbital fractures, of whom 29 patients (23.2%) had orbital entrapment fractures. The majority of patients presented with monocle hematoma (n = 23), diplopia (n = 20), and/or restricted extraocular eye movement (n = 14). While all patients with orbital entrapment fractures underwent three-dimensional imaging, 10 radiological reports (34.5%) did not include findings on orbital entrapment fractures. All patients underwent surgical exploration in less than 24 h. In 12 patients, clinical symptoms such as diplopia and restricted ocular elevation were documented upon postoperative evaluation before discharge. Considering the significant proportion of orbital entrapment fractures that are not noted on radiological imaging, prompt clinical examination should be initiated in pediatric patients at risk for orbital fractures. Urgent surgical intervention should be recommended in entrapment fractures.

Quantifying bone healing after mandibular displacement in orthognathic surgery.

Impaired bony healing following bilateral sagittal split osteotomy (BSSO) is a major unmet medical need for affected patients, and rare occurrences can hinder the identification of underlying risk factors. We hypothesised that osseous union following BSSO can be quantified using volumetric analysis, and we aimed to identify the risk factors for impaired bone healing. The percentage change in bony volume was measured in orthognathic patients following BSSO using two consecutive postoperative cone-beam computed tomography scans. Patients' characteristics and treatment parameters were documented, and correlation and regression analyses of these variables performed. Thirty-six patients (23 men and 13 women) with a mean (SD) age of 33.28 (11.86) years were included. The gap site (lingual versus buccal) (p < 0.01) had a significant impact on the change in volume. Age (p = 0.06) showed a trend towards significance. Initial width of the osteotomy gap, sex, and indication for surgery did not influence osseous healing. Increased age at surgery and the side of the buccal osteotomy are independent risk factors for impaired osseous healing following BSSO.

Oncological Outcome of Node-Positive Oral Squamous Cell Carcinomas Treated With Selective and Comprehensive Neck Dissection.

Selective neck dissection (SND) is the treatment of choice in patients with oral squamous cell carcinomas (OSCCs) and clinically node-negative necks (cN0). The treatment of patients with positive-staged necks (cN+) includes SND as well as comprehensive neck dissection (CND). The clear benefit of one or the other remains under debate. We aim to address this lack of clarity by analysing patients with OSCC staged with clinically node-positive necks, treated with either CND or SND using a level-by-level approach. This retrospective study included patients diagnosed with OSCC with clinically (cN+) and pathologically (pN+) positive cervical lymph nodes (LNs) with clear neck level categorization during the years 2010-2019. In total, 74 patients were analysed. Cox regression analysis found no significance for the type of ND being an independent risk factor, neither for overall survival (OS) nor for disease-free survival (DFS). Regional recurrence of CND cases (5.77%) was comparable to SND cases (9.09%). For OS, extracapsular spread (ECS) and male sex were identified as independent risk factors with poorer outcome. pT-stage and ECS were found to be independent risk factors for DFS. The results of this study suggest that both CND and SND may be viable treatment options for certain patients with OSCC pN+.

The risk of osteomyelitis after mandibular fracture is doubled in men versus women: analysis of 300,000 patients.

Postoperative complications following mandibular fracture treatment vary from local wound infections to severe conditions including osteomyelitis and impaired fracture healing. Several risk factors have been associated with the development healing disorders, including fracture localisation, treatment modality and substance abuse. However, limited research on the sex-specific influence of these complications exists. A total of about 300,000 female and male patients with mandibular fractures were examined in two cohorts. After matching for confounders (age, nicotine and alcohol dependence, malnutrition, overweight, anaemia, diabetes, osteoporosis and vitamin D deficiency), two cohorts were compared with propensity-score-matched patients according to outcomes (osteomyelitis, pseudoarthrosis and disruption of the wound) within 1 year after fracture. There were significant differences between female and male patients regarding the occurrence of osteomyelitis (odds ratio [OR] [95% confidence interval]: 0.621 [0.563; 0.686]) and disruption of the wound (OR [95% confidence interval]: 0.703 [0.632; 0.782]). Surprisingly, matching for the expected confounders did not change the results substantially. Sex plays a dominant role in determining the risk stratification for postoperative osteomyelitis and disruption of the wound, after accounting for other potential confounding factors. Additional research is needed to understand the underlying mechanisms and to develop sex-specific strategies to prevent these complications.

Pediatric Maxillofacial Trauma: Insights into Diagnosis and Treatment of Mandibular Fractures in Pediatric Patients.

Aim: To assess the diagnostic and therapeutic approaches in pediatric mandibular fractures with regards to fracture pattern and localization. Patients and methods: This retrospective study included patients under the age of 17 years that presented to the Department of Oral and Maxillofacial Surgery at Charité-Universitätsmedizin Berlin with mandibular fractures over an 11-year long period (2010-2020). Medical records were analyzed for age, gender, injury mechanism, clinical presentation, imaging modalities, fracture pattern, and fracture management. Statistical analyses included descriptive statistics, normality testing, and Mann-Whitney U tests. Results: A total of 91 pediatric patients (23 females and 68 males) presented with mandibular fractures. The majority of mandibular fractures occurred in patients aged 13-16 years (67.0%, n = 61). The main causes were activities of daily life (34.1%), followed by assault (25.3%). Malocclusion and pain upon mandibular joint compression were documented in 72.5% and 51.7% of patients, respectively. The most frequently applied radiological diagnostic tool was a panoramic X-ray (49.5%). The main fracture patterns were single (42.9%) and double fractures (48.4%). An age-adapted surgical approach using open reduction and internal fixation (ORIF) was the most frequent management (61.5%). A conservative approach was favored in cases of condylar head fractures. Resorbable plates were used in eight cases of ORIF (8.8%). Conclusion: Treatment regimens should be carefully selected based on the unique anatomy of the pediatric patient with regards to centers of growth and dentition phase, to restore stomatognathic function and to maintain adequate skeletal growth and eruption of teeth. Clinical significance: This study illustrates the challenges of mandibular fracture management in the pediatric patient. How to cite this article: Hofmann E, Koerdt S, Heiland M, et al. Pediatric Maxillofacial Trauma: Insights into Diagnosis and Treatment of Mandibular Fractures in Pediatric Patients. Int J Clin Pediatr Dent 2023;16(3):499-509.

Impact of the adjacent bone on pseudarthrosis in mandibular reconstruction with fibula free flaps.

BACKGROUND: Mechanical and morphological factors have both been described to influence the rate of pseudarthrosis in mandibular reconstruction. By minimizing mechanical confounders, the present study aims to evaluate the impact of bone origin at the intersegmental gap on osseous union. METHODS: Patients were screened retrospectively for undergoing multi-segment fibula free flap reconstruction of the mandible including the anterior part of the mandible and osteosynthesis using patient-specific 3D-printed titanium reconstruction plates. Percentage changes in bone volume and width at the bone interface between the fibula/fibula and fibula/mandible at the anterior intersegmental gaps within the same patient were determined using cone-beam computed tomography (CBCT). Additionally, representative samples of the intersegmental zones were assessed histologically and using micro-computed tomography (µCT). RESULTS: The bone interface (p = 0.223) did not significantly impact the change in bone volume at the intersegmental gap. Radiotherapy (p < 0.001), time between CBCT scans (p = 0.006) and wound healing disorders (p = 0.005) were independent risk factors for osseous non-union. Preliminary analysis of the microstructure of the intersegmental bone did not indicate morphological differences between fibula-fibula and fibula-mandible intersegmental bones. CONCLUSIONS: The bone interface at the intersegmental gap in mandibular reconstruction did not influence long-term bone healing significantly. Mechanical and clinical properties seem to be more relevant for surgical success.

Increased rate of pseudarthrosis in the anterior intersegmental gap after mandibular reconstruction with fibula free flaps: a volumetric analysis.

OBJECTIVES: Pseudarthrosis after mandibular reconstruction leads to chronic overload of the osteosynthesis and impedes dental rehabilitation. This study evaluates the impact of gap site on osseous union in mandible reconstruction using a new volumetric analysis method with repeated cone-beam computed tomography (CBCT). METHODS: The degree of bone regeneration was evaluated in 16 patients after mandible reconstruction with a fibula free flap and patient-specific reconstruction plates. Percentual bone volume and width changes in intersegmental gaps were retrospectively analyzed using a baseline CBCT in comparison to a follow-up CBCT. Patients' characteristics, plate-related complications, and gap sites (anterior/posterior) were analyzed. Detailed assessments of both gap sites (buccal/lingual/superior/inferior) were additionally performed. RESULTS: Intersegmental gap width (p = 0.002) and site (p < 0.001) significantly influence bone volume change over two consecutive CBCTs. An initial larger gap width resulted in a lower bone volume change. In addition, anterior gaps showed significantly less bone volume changes. Initial gap width was larger at posterior segmental gaps (2.97 vs 1.65 mm, p = 0.017). CONCLUSIONS: A methodology framework has been developed that allows to quantify pseuarthrosis in reconstructed mandibles using CBCT imaging. The study identifies the anterior segmental gap as a further risk factor for pseudarthrosis in reconstructions with CAD/CAM reconstruction plates. Future research should evaluate whether this outcome is related to the biomechanics induced at this site.

Treatment options for critical size defects - Comparison of different materials in a calvaria split model in sheep.

Bone defects of the craniofacial skeleton are often associated with aesthetic and functional impairment as well as loss of protection to intra- and extracranial structures. Solid titanium plates and individually adapted bone cements have been the materials of choice, but may lead to foreign-body reactions and insufficient osseointegration. In contrast, porous scaffolds are thought to exhibit osteoconductive properties to support bone ingrowth. Here, we analyse in critical size defects of the calvaria in sheep whether different bone replacement materials may overcome those remaining challenges. In a critical size defect model, bilateral 20 × 20 × 5-mm craniectomies were performed on either side of the sagittal sinus in 24 adult female blackheaded sheep. Bony defects were randomised to one of five different bone replacement materials (BRMs): titanium scaffold, biodegradable poly(d,l-lactic acid) calcium carbonate scaffold (PDLLA/CC), polyethylene 1 (0.71 mm mean pore size) or 2 (0.515 mm mean pore size) scaffolds and polymethyl methacrylate (PMMA)-based bone cement block. Empty controls (n = 3) served as references. To evaluate bone growth over time, three different fluorochromes were administered at different time points. At 3, 6 and 12 months after surgery, animals were sacrificed and the BRMs and surrounding bone analysed by micro-CT and histomorphometry. The empty control group verified that the calvaria defect in this study was a reliable critical size defect model. Bone formation in vivo was detectable in all BRMs after 12 months by micro-CT and histomorphometric analysis, except for the non-porous PMMA group. A maximum of bone formation was detected in the 12-months group for titanium and PDLLA/CC. Bone formation in PDLLA/CC starts to increase rapidly between 6 and 12 months, as the BRM resorbs over time. Contact between bone and BRM influenced bone formation inside the BRM. Empty controls exhibited bone formation solely at the periphery. Overall, porous BRMs offered bone integration to different extent over 12 months in the tested calvaria defect model. Titanium and PDLLA/CC scaffolds showed remarkable osseointegration properties by micro-CT and histomorphometric analysis. PDLLA/CC scaffolds degraded over time without major residues. Pore size influenced bone ingrowth in polyethylene, emphasising the importance of porous scaffold structure.

Direct Interaction of Avian Cryptochrome 4 with a Cone Specific G-Protein.

BACKGROUND: Night-migratory birds sense the Earth's magnetic field by an unknown molecular mechanism. Theoretical and experimental evidence support the hypothesis that the light-induced formation of a radical-pair in European robin cryptochrome 4a (ErCry4a) is the primary signaling step in the retina of the bird. In the present work, we investigated a possible route of cryptochrome signaling involving the α-subunit of the cone-secific heterotrimeric G protein from European robin. METHODS: Protein-protein interaction studies include surface plasmon resonance, pulldown affinity binding and Förster resonance energy transfer. RESULTS: Surface plasmon resonance studies showed direct interaction, revealing high to moderate affinity for binding of non-myristoylated and myristoylated G protein to ErCry4a, respectively. Pulldown affinity experiments confirmed this complex formation in solution. We validated these in vitro data by monitoring the interaction between ErCry4a and G protein in a transiently transfected neuroretinal cell line using Förster resonance energy transfer. CONCLUSIONS: Our results suggest that ErCry4a and the G protein also interact in living cells and might constitute the first biochemical signaling step in radical-pair-based magnetoreception.

Detectability of foreign body materials using X-ray, computed tomography and magnetic resonance imaging: A phantom study.

PURPOSE: To evaluate the effectiveness of plain radiography (X-ray. XR), computed tomography (CT) and magnetic resonance imaging (MR) in visualising commonly seen foreign bodies. A special focus was put on objects relevant to head and neck surgery. METHOD: Thirty-four commonly encountered objects of different compositions including wood, plastic, and glass were embedded in a gelatin gel phantom and imaged using XR, CT and MR. The success rates of radiologists in detecting and correctly identifying the foreign objects were evaluated. Subjective visibility was rated on a 4-point Likert scale. Objective visibility was analysed using region of interest-based contrast for CT. RESULTS: Sensitivity in foreign bodies detection was highest in MR (97.1 %) followed by CT (86.0 %) and x-ray (61.8 %). Success rates for the correct identification of the objects and material types were highest in MR (33.3 % and 39.2 %, respectively) followed by CT (25.5 % for both) and XR (16.7 % and 15.7 %). Overall, subjective visibility was rated higher in CT and MR imaging ("good visibility"), as compared to XR ("poor visibility"). Interreader agreement was high across modalities (Kendall's W = 0.935, 0.834 and 0.794 for XR, MR and CT, respectively). CONCLUSIONS: Detection and identification of non-ferromagnetic objects was most successful in MR followed by CT imaging in this experimental setup.