Reduction of CT Artifacts Using Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyphenylsulfone (PPSU), and Polyethylene (PE) Reconstruction Plates in Oral Oncology.

PURPOSE: Surgical reconstruction after segmental mandibulectomy in patients with oral cancer commonly requires implantation of titanium plates, which cause metallic artifacts in CT examinations detrimental for image quality. Therefore, the aim of the present study was to evaluate CT artifacts and image quality of the polymer plate materials polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyphenylsulfone (PPSU), and polyethylene (PE) in mandible reconstruction. METHODS: Five plates (titanium, PEEK, PEKK, PPSU, and PE) were successively surgically inserted in a human cadaveric specimen using eight (1) titanium and (2) zirconium oxide screws. Streak and blooming artifacts were assessed in 1 mm CT scans with and without metallic artifact reduction algorithms (MAR) in this cross-sectional study. The different plate materials were analyzed for their effect on Hounsfield unit (HU) values resulting in streak artifacts. Blooming artifacts were measured as virtual growth of plates compared to actual size. Subjective image quality was assessed by 3 independent observers. Statistics were conducted by multifactorial ANOVA and Bonferroni's post hoc test. RESULTS: Titanium (182.42 HU; SD ± 3.09) was associated with significantly more streak and blooming artifacts compared to the polymers PEEK (86.41 HU; SD ± 1.72; P < .001), PEKK (85.50 HU; SD ± 2.75; P < .001), PPSU (85.51 HU; SD ± 1.97; P < .001), and PE (85.52 HU; SD ± 3.33; P < .001) implants. No significant differences could be seen between the screw types (titanium vs zirconium oxide) (P = .75) or the activation or inactivation of MAR (P = .85). Image quality was best for PE and worst for titanium implants in combination with zirconium oxide screws. CONCLUSIONS: Polymers plate materials PEEK, PEKK, PPSU, and PE significantly reduce CT artifacts and improve image quality facilitating the radiological interpretation of implant surrounding tissues. This effect is beneficial for radiological tumor follow-up and CT-based planning of adjuvant radiotherapy.

Critical-size Defect Augmentation Using Sintered and Non-Sintered Bovine Bone Matrix - An Experimental Controlled Study in Minipigs.

PURPOSE: Xenogeneic bone substitute materials are often used for augmentation of larger bone defects. Purification methods for these materials vary, mainly in terms of temperature. The aim of this study was to determine in vivo how sintering affects quantitative and qualitative bone regeneration of 2 bovine augmentation materials. METHODS: A total of 56 critical size defects were set at the frontal bone of 14 domestic pigs (4 each) and filled randomly with either bovine, sintered hydroxyapatite (BO), bovine, non-sintered hydroxyapatite (BOS), local autologous bone (AB) or left empty. All defects were additionally covered with a collagen membrane. Specimens were harvested after 4 and 8 weeks and were evaluated histologically and histomorphometrically. RESULTS: Histologically new bone could be seen in every group. Significantly highest new bone formation was found in AB. No significant difference could be detected between BO and BOS. CONCLUSIONS: According to the results of this study, sintered bone substitute material remains histologically distinguishable but does not affect quantitative and qualitative bone regeneration.

Influence of different carrier materials on biphasic calcium phosphate induced bone regeneration.

OBJECTIVES: Biphasic calcium phosphate (BCP) is a bioceramic material successfully used in alloplastic bone augmentation. Despite many advantages, a disadvantage of BCP seems to be a difficult application and position instability. The aim of this study was to determine how different carrier materials influence BCP-induced quantitative and qualitative bone regeneration. MATERIALS AND METHODS: A total of 70 critical size defects were set in the frontal bone of 14 domestic pigs (5 each) and filled randomly with either BCP alone (BCP), BCP in combination with nano-hydroxyapatite (BCP + NHA), BCP embedded in native porcine type I/III collagen blocks (BCP + C), autologous bone (AB), or were left empty (ED). Specimens were harvested after 4 and 8 weeks and were evaluated histologically as well as histomorphometrically. RESULTS: Significantly lowest rate of new bone formation was found in ED (p = < 0.001) and BCP + NHA groups (p = 0.05). After 8 weeks, the highest percentage of new bone formation was observed in the BCP + C group. Fibrous matrix was detected highest in BCP alone. The lowest residual bone substitute material was found in BCP + C after 8 weeks. CONCLUSIONS: BCP-induced bone regeneration is indeed affected by different carrier types. Surface morphology and bioactive characteristics influence osseointegration and new bone formation in vivo. The combination of type I/III collagen seems most suitable for qualitative and quantitative bone regeneration. CLINICAL RELEVANCE: Stabilization of granular bone substitutes using type I/III collagen might be an alternative to granulates alone, indicating excellent volume stability, satisfactory plasticity, and easy application.

Analysis of Spatial and Temporal Distribution of Purinergic P2 Receptors in the Mouse Hippocampus.

ATP and other nucleotides are important glio-/neurotransmitters in the central nervous system. They bind to purinergic P2X and P2Y receptors that are ubiquitously expressed in various brain regions modulating various physiological and pathophysiological processes. P2X receptors are ligand-gated ion channels mediating excitatory postsynaptic responses whereas P2Y receptors are G protein-coupled receptors mediating slow synaptic transmission. A variety of P2X and P2Y subtypes with distinct neuroanatomical localization provide the basis for a high diversity in their function. There is increasing evidence that P2 receptor signaling plays a prominent role in learning and memory and thus, in hippocampal neuronal plasticity. Learning and memory are time-of-day-dependent. Moreover, extracellular ATP shows a diurnal rhythm in rodents. However, it is not known whether P2 receptors have a temporal variation in the hippocampus. This study provides a detailed systematic analysis on spatial and temporal distribution of P2 in the mouse hippocampus. We found distinct spatial and temporal distribution patterns of the P2 receptors in different hippocampal layers. The temporal distribution of P2 receptors can be segregated into two large time domains, the early to mid-day and the mid to late night. This study provides an important basis for understanding dynamic P2 purinergic signaling in the hippocampal glia/neuronal network.

Orbit in a Box: A Simplified Technique for Patient-Specific Virtually Planned Orbital Floor Reconstruction.

PURPOSE: Possibilities for the reconstruction of orbital floor fractures have been extensive for years with regard to materials, methods and differential indications and are inconsistent worldwide. With the spread of CAD/CAM techniques, new and mostly time-consuming possibilities for orbital floor reconstructions have been added. METHODS: The simple and time-efficient CT-to-patient-specific implant workflow presented here shows that a "form-box" can be created from a patient's computer tomography data set using planning software and a 3D printer. The box is then used to form a patient-specific implant for orbital floor reconstruction: here polydioxanone foil was used, for which stable thermoplastic deformability has been demonstrated for 3D reconstructions. RESULTS: Patient-specific thermoplastic shaping of polydioxanone is feasible in a theoretical clinical setting, though its thermoplastic shaping is not yet certified for clinical use. However, a flexible adaptation of the "form-box" design to other materials is possible by setting a single planning parameter. CONCLUSIONS: The simple structure of the box and its straightforward planning/fabrication process with widely available low-cost materials offer the possibility that a surgeon without a 3D specialist can produce a "form-box" for next day surgery if needed.

Removal of stones from the superficial lobe of the submandibular gland (SMG) via an intraoral endoscopy-assisted sialolithotomy.

OBJECTIVES: Sialolithiasis is the most common cause of chronic sialadenitis of the submandibular gland (SMG). Symptomatic superficial lobe stones are often treated by submandibulectomy. A gland preserving operation allows for transoral stone removal through endoscopically assisted sialolithotomy. Herein, we provide clinical and sonographical follow-up data in patients who underwent sialolithotomy under general anesthesia. MATERIALS AND METHODS: Sixty patients treated at the Department of Oral and Maxillofacial Surgery at Düsseldorf University Hospital for superficial lobe sialolithiasis of SMG were included in this study. All received transoral sialolithotomy under general anesthesia. Follow-up was conducted via standardized patient questionnaires, clinical examination, and B-mode and color Doppler sonography. RESULTS: Mean patient age was 48.9 years. 56.6% of right and 43.4% of left SMG were affected. Mean follow-up was 45 months. Fifty-five of 59 detected stones could be removed. Mean operation time was 71 min. 3.3% of patients reported recurrent episodes of postoperative pain and 10% felt recurrent episodes of gland swelling. Persistent postoperative lingual nerve hypesthesia was described in one patient. No facial nerve damages occurred. Salivary flow rates remained reduced in most of the affected glands upon stone removal. Sonographical follow-up data of the previously affected SMG after intraoral endoscopy-assisted sialolithotomy showed a regular gland size in 70.8% of cases, a parenchyma free of inflammation in 93.8%, and without signs of fibrosis in 72.9% of cases. 68.7% of patients showed a regular structure of Wharton's duct at time of follow-up. In total, 89.6% of patients were diagnosed stone-free within both glands on follow-up. No case required subsequent submandibulectomy. CONCLUSIONS: Sialolithotomy of Wharton's duct for removal of stones from the SMG's superficial lobe is a promising alternative to submandibulectomy. CLINICAL RELEVANCE: Reduction of postoperative morbidity through endoscopically assisted sialolithotomy for removal of superficial lobe stones from SMG. TRIAL REGISTRATION: Ethics Committee of Heinrich-Heine-University Düsseldorf (no. 5586).

Time-of-day-dependent expression of purinergic receptors in mouse suprachiasmatic nucleus.

Purinergic P2X and P2Y receptors are involved in mediating intercellular signalling via purines such as adenosine triphosphate (ATP). P2X and P2Y receptors have been implicated in numerous body functions including learning, memory and sleep. All of these body functions show time-of-day-dependent variations controlled by the master circadian oscillator located in the suprachiasmatic nucleus (SCN). Evidence exists for a role of purinergic signalling in intercellular coupling within SCN. However, few studies have been performed on the expression of purinergic receptors in SCN. Therefore, we analyse the expression of seven P2X (P2X1-7) and eight P2Y (P2Y1-2, 4, 6, 11-14) receptors in mouse SCN and address their time-of-day-dependent variation by using immunohistochemistry and real-time polymerase chain reaction. At the early light phase, P2X and P2Y receptors show a low to moderate, homogenously distributed immunoreaction throughout SCN. P2Y13 reveals strong immunoreaction in fibres within the core region of SCN. From the fifteen analysed P2 receptors, seven exhibit a time-of-day-dependent variation in SCN. P2X1 immunoreaction is very low in the early light phase with a minor increase at the end of the dark phase. P2X4 immunoreaction strongly increases during the dark phase in soma cells in the core region and in a dense network of fibres in the shell region of SCN. P2X3 immunoreaction is moderately elevated during the dark phase. Conversely, immunoreaction for P2Y2, P2Y12 and P2Y14 moderately increases at the early light phase and P2Y6 immunoreaction displays a moderate increase at the mid-light phase. Thus, this study demonstrates a time-of-day-dependent variation of P2 receptors in mouse SCN.

Accuracy and Sterilizability of In-House Printed Patient-Specific Aortic Model for Surgeon-Modified Stent Grafts-A Workflow Description for Emergency Aortic Endovascular Procedures.

Introduction: The use of 3D-printed aortic models for the creation of surgeon-modified endoprostheses represents a promising avenue in aortic surgery. By focusing on the potential impact of sterilization on model integrity and geometry, this report sheds light on the suitability of these models for creating customized endoprostheses. The study presented here aimed to investigate the safety and viability of 3D-printed aortic models in the context of sterilization processes and subsequent remodeling. Methods: The study involved the fabrication of 3D-printed aortic models using patient-specific imaging data and established additive manufacturing techniques. Five identical aortic models of the same patient were printed. Two models were subjected to sterilization and two to disinfection using commonly employed methods, and one model remained untreated. The models were checked by in-house quality control for deformation (heat map analyses) after the sterilization and disinfection processes. Three models (sterilized, disinfected, and untreated) were sent for ex-house (Lufthansa Technik, AG, Materials Technologies and Central Laboratory Services, Hamburg, Germany) evaluation and subsequent quantification of possible structural changes using advanced imaging and measurement technologies (macroscopic and SEM/EDX examinations). After sterilization and disinfection, each aortic model underwent sterility checks. Results: Based on macroscopic and SEM/EDX examinations, distinct evidence of material alterations attributed to a treatment process, such as a cleaning procedure, was not identified on the three implants. Comparative material analyses conducted via the EDX technique yield consistent results for all three implants. Disinfected and sterilized models tested negative for common pathogens. Conclusions: The evaluation of 3D-printed aortic models' safety after sterilization as well as their suitability for surgeon-modified endoprostheses is a critical step toward their clinical integration. By comprehensively assessing changes in model integrity and geometry after sterilization, this research has contributed to the broader understanding of the use of 3D-printed models for tailor-made endovascular solutions. As medical technologies continue to evolve, research endeavors such as this one can serve as a foundation for harnessing the full potential of 3D printing to advance patient-centered care in aortic surgery.

Plasma Electrolytic Polished Patient-Specific Orbital Implants in Clinical Use-A Technical Note.

This technical note describes the technique of plasma electrolytic polishing on orbital patient-specific implants and demonstrates clinical handling and use by the insertion of a plasma electrolytic polished orbital implant into a patient.

Metallic Artifact Reduction in Midfacial CT Scans Using Patient-Specific Polymer Implants Enhances Image Quality.

Midfacial reconstruction after tumor resection surgery is commonly conducted by using autologous bone grafts or alloplastic implants. Titanium is the most frequently used osteosynthesis material in these cases but causes disturbing metallic artifacts in CT imaging. The purpose of this experimental study was to evaluate whether the use of midfacial polymer implants reduces metallic artifacts in CT imaging to improve image quality. Zygomatic titanium (n = 1) and polymer (n = 12) implants were successively implanted in a human skull specimen. Implants were analyzed for their effect on Hounsfield Unit values (streak artifacts) and virtual growth in CT images (blooming artifacts) as well as image quality. Multi-factorial ANOVA and Bonferroni's post hoc test were used. Titanium (173.7 HU; SD ± 5.1) and hydroxyapatite containing polymers (155.3 HU; SD ± 5.9) were associated with significantly more streak artifacts compared to all other polymer materials. There was no significant difference in blooming artifacts between materials. The metallic artifact reduction algorithm showed no significant difference. Image quality was slightly better for polymer implants compared to titanium. Personalized polymer implants for midfacial reconstruction significantly reduce metallic artifacts in CT imaging which improves image quality. Hence, postoperative radiation therapy planning and radiological tumor aftercare around the implants are facilitated.

Usage of Object Matching Algorithms Combined with Mixed Reality for Enhanced Decision Making in Orbital Reconstruction-A Technical Note.

This technical note describes the usage of object matching to virtually compare different modes of reconstruction in orbital trauma and display the results to the surgeon and the patient pre-operatively via mixed reality devices for enhanced surgical decision making and immersive patient education. A case of an orbital floor fracture is presented for which surface and volume matching were implemented to compare orbital reconstruction utilizing pre-fabricated titanium meshes versus patient-specific implants. The results could be visualized by mixed reality devices to further enhance surgical decision-making. The data sets were demonstrated to the patient in mixed reality for immersive patient education and enhanced shared decision making. The advantages of the new technologies are discussed in view of the new possibilities of improved patient education and informed consent processes, as well as new ways of teaching medical trainees.

Primary Orbital Reconstruction with Selective Laser Melting (SLM) of Patient-Specific Implants (PSIs): An Overview of 96 Surgically Treated Patients.

Contemporary advances in technology have allowed the transfer of knowledge from industrial laser melting systems to surgery; such an approach could increase the degree of accuracy in orbital restoration. The aim of this study was to examine the accuracy of selective laser melted PSIs (patient-specific implants) and navigation in primary orbital reconstruction. Ninety-six patients with orbital fractures were included in this study. Planned vs. achieved orbital volumes (a) and angles (b) were compared to the unaffected side (n = 96). The analysis included the overlay of post-treatment on planned images (iPlan 3.0.5, Brainlab®, Feldkirchen, Germany). The mean difference in orbital volume between the digitally planned orbit and the postoperative orbit was 29.16 cm3 (SD 3.54, presurgical) to 28.33 cm3 (SD 3.64, postsurgical, t = 5.00, df = 95.00; p < 0.001), resulting in a mean volume difference (planned vs. postop) of less than 1 cm3. A 3D analysis of the color mapping showed minor deviations compared to the mirrored unaffected side. The results suggested that primary reconstruction in complex orbital wall fractures can be routinely achieved with a high degree of accuracy by using selective laser melted orbital PSIs.

Simultaneous PSI-Based Orthognathic and PEEK Bone Augmentation Surgery Leads to Improved Symmetric Facial Appearance in Craniofacial Malformations.

(1) The aim of the present study was to compare the outcome of facial symmetry after simultaneous digitally planned patient-specific implant (PSI-) based orthognathic surgery and polyether ether ketone (PEEK) bone augmentation in patients with craniofacial malformations. (2) To evaluate the outcome of the two different surgical approaches (conventional PSI-based orthognathic surgery versus simultaneous PSI-based orthognathic surgery with PEEK bone augmentation), a comparison of five different groups with a combination of the parameters (A) with vs. without laterognathia, (B) syndromic vs. non-syndromic, and (C) surgery with vs. without PEEK bone augmentation was conducted. The digital workflow comprised cone beam CT (CBCT) scans and virtual surgery planning for all patients in order to produce patient specific cutting guides and osteosynthesis plates. Additionally, deformed skulls were superimposed by a non-deformed skull and/or the healthy side was mirrored to produce PSI PEEK implants for augmentation. Retrospective analyses included posterior-anterior conventional radiographs as well as en face photographs taken before and nine months after surgery. (3) Simultaneous orthognathic surgery with PEEK bone augmentation significantly improves facial symmetry compared to conventional orthognathic surgery (6.5%P (3.2-9.8%P) (p = 0.001). (4) PSI-based orthognathic surgery led to improved horizontal bone alignment in all patients. Simultaneous PEEK bone augmentation enhanced facial symmetry even in patients with syndrome-related underdevelopment of both soft and hard tissues.

Analysis of Spontaneous and Induced Osteogenic Differentiation in 3D-micromasses of Human Multipotent Stem Cells.

BACKGROUND/AIM: Craniofacial reconstruction of extensive bone defects causes high morbidity to patients. Contemporary reconstructive surgery aims at restoring lost bone with either autogenous bone or substitutes. Multipotent unrestricted somatic stem cells (USSC) show a potential for osteoblast differentiation and are increasingly used in tissue engineering. The osteogenic potential of USSC micromasses influenced by dexamethasone, ascorbic acid and ß-glycerophosphate (DAG) seems promising. The present study evaluated the effects of DAG and MAPK, ERK and PI3K/Akt-pathway inhibitors on growth and mineralization of USSC micromasses. MATERIALS AND METHODS: Cells: i) USSC-18 (female, Passage 8), ii) USSC-8 (female Passage 9), and iii) USSC-8/17 (male, Passage 8), all cultured in 350 ml DMEM, with 150 ml fetal bovine serum, 5 ml penicillin/streptomycin and 5 ml L-glutamine. Differentiation was induced using 50 µM dexamethasone in DMEM, 50 mM ascorbic acid in PBS and 1 M ß-glycerolphosphate in PBS. Microtome slices were dyed with OsteoImage™ and analyzed under fluorescence microscopy. RESULTS: Significant increase in size and mineralization of DAG-treated micromasses was found on days 3 (p<0.001), 6 (p<0.001) and 7 (p<0.001). The ERK-pathway inhibitor, FR180204, significantly reduced micromass growth and mineralization in non-DAG treated cells (p<0.001) but showed increased mineralization in DAG-treated cells (p=0.014). The PI3K/Akt-pathway inhibitor, LY294002, did not significantly affect micromass growth but significantly decreased mineralization (p<0.001). The MAP-kinase inhibitor, U0126, significantly reduced micromass growth (p=0.001) and mineralization (p=0.001) of DAG-treated cells. CONCLUSION: DAG is a strong initiator of osteogenic differentiation. The PI3K/Akt-pathway inhibitor and the ERK-pathway inhibitor, FR180204, control osteogenic differentiation of 3D-micromasses. These results may facilitate preconditioning of cell cultures in guided tissue regeneration.

Influence of Xenogeneic and Alloplastic Carriers for Bone Augmentation on Human Unrestricted Somatic Stem Cells.

Alloplastic and xenogeneic bone grafting materials are frequently used for bone augmentation. The effect of these materials on precursor cells for bone augmentation is yet to be determined. The aim of this study was to ascertain, in vitro, how augmentation materials influence the growth rates and viability of human unrestricted somatic stem cells. The biocompatibility of two xenogeneic and one alloplastic bone graft was tested using human unrestricted somatic stem cells (USSCs). Proliferation, growth, survival and attachment of unrestricted somatic stem cells were monitored after 24 h, 48 h and 7 days. Furthermore, cell shape and morphology were evaluated by SEM. Scaffolds were assessed for their physical properties by Micro-CT imaging. USSCs showed distinct proliferation on the different carriers. Greatest proliferation was observed on the xenogeneic carriers along with improved viability of the cells. Pore sizes of the scaffolds varied significantly, with the xenogeneic materials providing greater pore sizes than the synthetic inorganic material. Unrestricted somatic stem cells in combination with a bovine collagenous bone block seem to be very compatible. A scaffold's surface morphology, pore size and bioactive characteristics influence the proliferation, attachment and viability of USSCs.

Mechanical Fatigue Performance of Patient-Specific Polymer Plates in Oncologic Mandible Reconstruction.

Mandible defects are conventionally reconstructed using titanium plates. However, titanium causes metallic artifacts which impair radiological imaging. This study aims at evaluating mechanical fatigue of radiolucent fiber-reinforced polyetheretherketone (f-PEEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polyphenylsulfone (PPSU) polymer plates for mandible reconstruction. A total of 30 plates (titanium [n = 6], f-PEEK [n = 6], PEEK [n = 6], PEKK [n = 6], PPSU [n = 6]) were implanted in synthetic mandibulectomized polyurethane mandibles. Servo-pneumatic mechanical testing with cyclic application of 30−300 N at 3 Hz was conducted. Bite forces were 70% on the unresected and 30% on the resected side. Total number of cycles was set to 250,000. Testing was aborted in case of plate or screw failure. Axial load to failure was tested with a speed of 1 mm/s. Kruskal−Wallis and Dunn's post hoc tests were used. Titanium, f-PEEK, and PEEK showed no failure in fatigue testing and PPSU (p < 0.001) failed against titanium, f-PEEK, PEEK, and PEKK. Titanium allowed the highest load to failure compared to f-PEEK (p = 0.049), PEEK (p = 0.008), PEKK (p < 0.001), and PPSU (p = 0.007). f-PEEK, PEEK, and PEKK withstood expected physiological bite force. Although titanium plates provided the highest fatigue strength, f-PEEK and PEEK plates showed no failure over 250,000 chewing cycles indicating sufficient mechanical strength for mandible reconstruction.

Lethal Aeromonas veronii Sepsis in the Course of Medicinal Leech Therapy.

A patient with oral squamous cell carcinoma (OSCC) underwent complex surgical tumor therapy, including the reconstruction of soft tissues using a radial forearm flap. Due to venous congestion that could only partly be resolved by revision surgery, leech therapy was started on the second postoperative day. The patient developed pneumonia and sepsis and died as a result of septic shock, despite having received targeted broad-spectrum antibiotic therapy since day 5. Aeromonas spp. were cultured from both the patient's specimens and unused leeches. Biochemical identification and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) yielded inconsistent identification results. Finally, microbiological identification of Aeromonas spp. was performed via 16S rDNA sequencing and use of the basic local alignment search tool (BLAST), and strains from both the patient and the leeches were identified as Aeromonas veronii. Aeromonas spp. strains derived from the patient and leeches and independent laboratory strains were submitted to randomly amplified polymorphic DNA (RAPD) subtyping. RAPD of A. veronii strains from both sources revealed an identical pattern, strongly suggesting the transmission of A. veronii from the leeches to the patient. Physicians should be aware of the potential for severe lethal infections as a fatal side-effect of leech therapy in critically ill patients, which should be addressed using antibiotic prophylaxis.

Genetic analysis of single disseminated tumor cells in the lymph nodes and bone marrow of patients with head and neck squamous cell carcinoma.

Considering the limited information on the biology and molecular characteristics of disseminated tumor cells (DTCs) in head and neck squamous cell carcinoma (HNSCC), we examined the genomic alterations in DTCs from HNSCCs and their potential clinical relevance. To analyze both the lymphatic and hematogenous routes of tumor cell dissemination, we investigated samples from lymph nodes (LNs) and bone marrow (BM) of 49 patients using immunofluorescence double staining for epithelial cells expressing cytokeratin 18 (KRT18) and/or epithelial cell adhesion molecules (EpCAM, CD326). The identified marker-positive cells were isolated by micromanipulation followed by single-cell whole-genome amplification and metaphase-based comparative genomic hybridization (mCGH) to determine genome-wide copy number alterations. The findings were correlated with clinical parameters and follow-up data. We detected chromosomal aberrations in KRT18- and EpCAM-positive cells from both compartments; BM-derived cells showed a significantly higher percentage of aberrant genome (PAG) per cell than cells detected in LNs. No significant association was found between DTC data and clinical follow-up. Genomic profiling of BM-DTCs revealed genomic alterations typical for HNSCC, suggesting hematogenous dissemination of subclones around the time of surgery. In contrast, DTC data in LNs revealed that several marker-positive cells were not of malignant origin, indicating the presence of epithelial glandular inclusions in parts of the processed neck LN samples. Therefore, DTC detection of LNs in the neck based only on epithelial markers is not advisable and requires detection of chromosomal instability (CIN), gene mutations, or additional markers, which have yet to be identified. Nevertheless, our investigation paves the way for larger studies to focus on HNSCC BM-DTCs with high-resolution methods to gain deeper insights into the biology of hematogenous metastasis in this cancer.

Image quality of a portable X-ray device (Nomad Pro 2) compared to a wall-mounted device in intraoral radiography.

OBJECTIVES: The aim of this study was to determine whether a handheld (HH) X-ray device (Nomad Pro 2) is capable of producing equivalent or even superior X-ray image quality in comparison to a wall-mounted (WM) dental X-ray unit (Heliodent Plus) on the basis of objectifiable image quality parameters. METHODS: Anatomical, radiological and biological dental X-ray image quality parameters of a handheld dental X-ray device (Nomad Pro 2, Kavo Kerr, Biberach, Germany) were compared to a standard wall-mounted dental X-ray unit (Heliodent Plus, Sirona Dental Systems, Bensheim, Germany) using a maxillofacial phantom. In addition, the effect of different operators (dentists, dental students, dental assistants) on the dental X-ray image quality was measured. RESULTS: HH and WM devices showed comparable image quality for anterior teeth, premolars, molars and bitewing images. During the two-month investigational period, the radiation exposure level for the operator of the Nomad Pro 2 was 0.1 mSv for 203 images. Dentists as the highest trained personnel enrolled in the study achieved better image quality with the Nomad Pro 2 as compared to dental students and dental assistants, especially in the molar region. CONCLUSIONS: A HH device delivers a comparable image quality to a WM device. In addition, there seem to be short learning curves with regard to image acquisition when using a handheld device, which is further minimised by the previous training of the operating personnel. HH dental X-ray devices, such as the Nomad Pro 2 are a promising adjunct for dental radiology in cases where WM units are of limited practicability.

Navigated Recovery of Fractured Dental Injection Needles: Case Report and Suggestions for Management during Pandemic Crises.

Dislocation of a fractured hypodermic needle is a complication requiring immediate and adequate emergency treatment. In this case report, 3D navigation is evaluated for its use to recover a quickly moving fractured needle. The needle was recovered safely, but it could be demonstrated that navigational planning has to be conducted right before surgery and other navigational tools, such as ultrasound, should be considered as well. Furthermore, an approach is suggested for treatment during pandemic crises such as COVID-19.