24 results on '"Wilkat M"'
Search Results
2. Adenosine receptor 2B activity promotes autonomous growth, migration as well as vascularization of head and neck squamous cell carcinoma cells
- Author
-
Bast, H, additional, Wilkat, M, additional, Drees, R, additional, Dünser, J, additional, Brhel, M, additional, Azoitei, N, additional, Marienfeld, R, additional, Frank, F, additional, Ushmorov, A, additional, Greve, J, additional, Goldberg-Bockhorn, E, additional, Theodoraki, Marie-Nicole, additional, Döscher, J, additional, Laban, S, additional, Schuler, P, additional, Hoffmann, TK., additional, and Brunner, C, additional
- Published
- 2020
- Full Text
- View/download PDF
3. Die Aktivität des Adenosinrezeptors A2B fördert autonomes Wachstum, Migration und Vaskularisation von Kopf-Hals-Karzinom-Zellen
- Author
-
Bast, H, additional, Wilkat, M, additional, Drees, R, additional, Dünser, J, additional, Brhel, M, additional, Azoitei, N, additional, Marienfeld, R, additional, Frank, F, additional, Ushmorov, A, additional, Greve, J, additional, Goldberg-Bockhorn, E, additional, Theodoraki, Marie-Nicole, additional, Döscher, J, additional, Laban, S, additional, Schuler, P, additional, Hoffmann, TK, additional, and Brunner, C, additional
- Published
- 2020
- Full Text
- View/download PDF
4. Analysis of the influence of adenosine on HNSCC cell lines
- Author
-
Wilkat, M, additional, Frank, F, additional, Schuler, P, additional, Laban, S, additional, Hoffmann, T, additional, and Brunner, C, additional
- Published
- 2018
- Full Text
- View/download PDF
5. Analyse des Einflusses von Adenosin auf Plattenepithelkarzinomzelllinien etabliert von Tumoren des Kopf-Hals-Bereiches
- Author
-
Wilkat, M, additional, Frank, F, additional, Schuler, P, additional, Laban, S, additional, Hoffmann, T, additional, and Brunner, C, additional
- Published
- 2018
- Full Text
- View/download PDF
6. 3-Dimensional accuracy of navigation-guided bimaxillary orthognathic surgery: A systematic review and meta-analysis.
- Author
-
Saigo L, Schrader F, Rana M, and Wilkat M
- Subjects
- Humans, Maxilla surgery, Surgical Navigation Systems, Orthognathic Surgical Procedures methods, Imaging, Three-Dimensional methods, Surgery, Computer-Assisted methods
- Abstract
The transfer of a virtual orthognathic surgical plan to the patient still relies on the use of occlusal splints, which have limitations for vertical positioning of the maxilla. The use of real-time navigation has been proposed to enhance surgical accuracy. This systematic review (PROSPERO CRD42024497588) aimed to investigate if surgical navigation can improve the three-dimensional accuracy of orthognathic surgery. The inclusion criteria were orthognathic surgery, use of intra-operative navigation and quantitative assessment of surgical accuracy. The exclusion criteria were non-bimaxillary orthognathic surgeries, non-clinical studies, studies without post-operative 3D analysis and publications not in the English language. A search of PubMed, Embase and Cochrane Library generated 940 records, of which 12 were found relevant. Risk of bias was assessed done using the Joanna Briggs Institute Critical Appraisal Checklist Tool. Among the included studies, there were nine of observational character and three randomized control studies (RCTs). All studies demonstrated promising outcomes with reported good surgical accuracy within a 2 mm difference between the planned and post-surgical result. Meta-analysis of two RCTs was carried out and results were in favor of surgical navigation with a total odds ratio of 4.44 [2.11, 9.37] and an overall effect outcome of Z = 3.92 (p < 0.0001). Navigation was up to 0.60 mm more accurate than occlusal wafers only (p < 0.001). However, there were variations in the application of surgical navigation and methods of analysis, leading to a heterogenous data set. Future studies should focus on standardized protocols and analysis methods to further validate the use of surgical navigation in orthognathic surgery. Despite some limitations, surgical navigation shows potential as a valuable tool in improving the accuracy of orthognathic surgery., Competing Interests: Declaration of competing interest The authors have no conflict of interest to declare., (Copyright © 2024 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
7. Enhancing surgical occlusion setting in orthognathic surgery planning using mixed reality technology: a comparative study.
- Author
-
Wilkat M, Schrader F, Trusch J, Karnatz N, Becker K, Saigo L, and Rana M
- Subjects
- Humans, Female, Male, Adult, Models, Dental, Virtual Reality, Surgery, Computer-Assisted methods, Imaging, Three-Dimensional methods, Orthognathic Surgical Procedures methods, Patient Care Planning, Dental Occlusion
- Abstract
Objectives: Orthognathic surgery necessitates precise occlusal alignment during surgical planning, traditionally achieved through manual alignment of physical dental models as the recognized gold standard. This study aims to evaluate the efficacy of mixed reality technology in enhancing surgical occlusion setting compared to traditional physical alignment and an established virtual method, addressing the research question: Can mixed reality technology improve the accuracy and efficiency of occlusion setting in orthognathic surgery planning?, Materials & Methods: This experimental study compared the surgical occlusion settings of 30 orthognathic cases using three methods: a new virtual method with mixed reality technology, the traditional gold standard of physical alignment, and an established virtual occlusion method using the IPS Case Designer (KLS Martin SE & Co. KG, Tuttlingen, Germany)., Results: Results indicated that surgical occlusions set with mixed reality technology were comparable to the conventional method in terms of maxillary movement and occlusal relationship. Differences observed were within the inter-observer variability of the gold standard. Both virtual methods tended to position the maxilla more anteriorly, resulting in fewer occlusal contacts. However, virtual occlusion demonstrated clinical applicability, achieving an average of 11 occlusal contacts with a bilaterally symmetrical distribution along the dental arch., Conclusions: The mixed reality environment provides an intuitive and flexible experience for setting surgical occlusion, eliminating the need for costly 3D-printed physical models or the automatic calculations required by other virtual occlusion methods, thereby offering maximum freedom., Clinical Relevance: As a novel form of virtual occlusion, it presents a comprehensive tool that contributes to a timely and cost-effective full digital workflow of orthognathic surgery planning., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
8. Intraoral Scanning Enables Virtual-Splint-Based Non-Invasive Registration Protocol for Maxillofacial Surgical Navigation.
- Author
-
Wilkat M, Saigo L, Kübler N, Rana M, and Schrader F
- Abstract
Background/Objectives: Surgical navigation has advanced maxillofacial surgery since the 1990s, bringing benefits for various indications. Traditional registration methods use fiducial markers that are either invasively bone-anchored or attached to a dental vacuum splint and offer high accuracy but necessitate additional imaging with increased radiation exposure. We propose a novel, non-invasive registration protocol using a CAD/CAM dental splint based on high-resolution intraoral scans. Methods : The effectiveness of this method was experimentally evaluated with an ex vivo 3D-printed skull measuring the target registration error (TRE). Surgical application is demonstrated in two clinical cases. Results : In the ex vivo model, the new CAD/CAM-splint-based method achieved a mean TRE across the whole facial skull of 0.97 ± 0.29 mm, which was comparable to traditional techniques like using bone-anchored screws (1.02 ± 0.23 mm) and dental vacuum splints (1.01 ± 0.33 mm), while dental anatomical landmarks showed a lower accuracy with a mean TRE of 1.84 ± 0.44 mm. Multifactorial ANOVA confirmed significant differences in TRE based on the registration method and the navigated level of the facial skull ( p < 0.001). In clinical applications, the presented method demonstrated high accuracy for both midfacial and mandibular surgeries. Conclusions : Our results suggest that this non-invasive CAD/CAM-splint-based method is a viable alternative to traditional fiducial marker techniques, with the potential for broad application in maxillofacial surgery. This approach retains high accuracy while eliminating the need for supplementary imaging and reduces patient radiation exposure. Further clinical trials are necessary to confirm these findings and optimize splint design for enhanced navigational accuracy.
- Published
- 2024
- Full Text
- View/download PDF
9. Mixed Reality as a Digital Visualisation Solution for the Head and Neck Tumour Board: Application Creation and Implementation Study.
- Author
-
Karnatz N, Schwerter M, Liu S, Parviz A, Wilkat M, and Rana M
- Abstract
The preparation and implementation of interdisciplinary oncological case reviews are time-consuming and complex. The variety of clinical and radiological information must be presented in a clear and comprehensible manner. Only if all relevant patient-specific information is demonstrated in a short time frame can well-founded treatment decisions be made on this basis. Mixed reality (MR) technology as a multimodal interactive user interface could enhance understanding in multidisciplinary collaboration by visualising radiological or clinical data. The aim of the work was to develop an MR-based software prototype for a head and neck tumour board (HNTB) to support clinical decision-making. The article describes the development phases and workflows in the planning and creation of a MR-based software prototype that were required to meet the multidisciplinary characteristics of a HNTB.
- Published
- 2024
- Full Text
- View/download PDF
10. Accuracy and Sterilizability of In-House Printed Patient-Specific Aortic Model for Surgeon-Modified Stent Grafts-A Workflow Description for Emergency Aortic Endovascular Procedures.
- Author
-
Wilkat M, Lommen J, Rana M, Kübler N, Wienemann T, Braß SM, Ziegler RT, Mazrekaj A, Knapsis A, Schelzig H, Wagenhäuser MU, and Arnautovic A
- Abstract
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.
- Published
- 2024
- Full Text
- View/download PDF
11. A New Approach to Virtual Occlusion in Orthognathic Surgery Planning Using Mixed Reality-A Technical Note and Review of the Literature.
- Author
-
Wilkat M, Liu S, Schwerter M, Schrader F, Saigo L, Karnatz N, Kübler NR, and Rana M
- Abstract
Orthognathic surgery plays a vital role in correcting various skeletal discrepancies of the maxillofacial region. Achieving optimal occlusion is a fundamental aspect of orthognathic surgery planning, as it directly influences postoperative outcomes and patient satisfaction. Traditional methods for setting final occlusion involve the use of dental casts which are time-consuming, prone to errors and cannot be easily shared among collaborating specialties. In recent years, advancements in digital technology have introduced innovative approaches, such as virtual occlusion, which may offer enhanced accuracy and efficiency in orthognathic surgery planning. Furthermore, the emergence of mixed reality devices and their 3D visualization capabilities have brought about novel benefits in the medical field, particularly in computer-assisted planning. This paper presents for the first time a prototype tool for setting virtual occlusion during orthognathic surgery planning using mixed reality technology. A complete walkthrough of the workflow is presented including an explanation of the implicit advantages of this novel tool. The new approach to defining virtual occlusion is set into context with other published methods of virtual occlusion setting, discussing advantages and limitations as well as concepts of surgical occlusion for orthognathic surgery.
- Published
- 2023
- Full Text
- View/download PDF
12. Usage of Object Matching Algorithms Combined with Mixed Reality for Enhanced Decision Making in Orbital Reconstruction-A Technical Note.
- Author
-
Wilkat M, Karnatz N, Schrader F, Schorn L, Lommen J, Parviz A, Möllmann HL, and Rana M
- Abstract
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.
- Published
- 2023
- Full Text
- View/download PDF
13. Plasma Electrolytic Polished Patient-Specific Orbital Implants in Clinical Use-A Technical Note.
- Author
-
Schorn L, Wilkat M, Lommen J, Borelli M, Muhammad S, and Rana M
- Abstract
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.
- Published
- 2023
- Full Text
- View/download PDF
14. Simultaneous PSI-Based Orthognathic and PEEK Bone Augmentation Surgery Leads to Improved Symmetric Facial Appearance in Craniofacial Malformations.
- Author
-
Kerkfeld V, Schorn L, Depprich R, Lommen J, Wilkat M, Kübler N, Rana M, and Meyer U
- Abstract
(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., Competing Interests: The authors declare no conflict of interest.
- Published
- 2022
- Full Text
- View/download PDF
15. Prospective Evaluation of Two Wall Orbital Fractures Involving the Medial Orbital Wall: PSI Reconstruction versus PDS Repair-Worth the Effort?
- Author
-
Wilkat M, Hufendiek K, Karahisarlioglu M, Borrelli M, Sproll C, and Rana M
- Abstract
Proper treatment of the two-wall fractured orbit is still controversial. Specifically, there is no consensus on the issue of the necessity of medial orbital wall repair. With anatomically critical structures at risk during the surgical approach, surgeons' view on the necessity of medial orbital wall repair often is restricted and an aesthetically disturbing enophthalmos is more likely to be accepted. Therefore, treatment options range from leaving the medial wall without repair to reconstruction with autogenous tissue or alloplastic materials, which can lead to moderate to severe side effects. However, emerging technologies such as patient-specific implants (PSI) offer a reliable and anatomically correct reconstruction of the bony orbit. This study aimed to evaluate the outcome of full orbital reconstruction using PSIs compared to only orbital floor repair using PDS (bioresorbable polydioxanone) foils leaving the medial orbital wall untouched in traumatic two-wall orbital fractures. Of all patients treated at the University Hospital of Düsseldorf between 2017 and 2019 who suffered from traumatic orbital fracture, only patients with a two-wall orbital fracture involving both the orbital floor and the medial wall (n = 68) were included. Patients were treated either with a PSI (n = 35) or a PDS foil (n = 33). Primary outcome parameters were ophthalmological disturbances analyzed via clinical investigation and intra-orbital angles, volumes and implant position analyzed with radiological 3D-datasets. While a two-wall reconstruction using PSIs led to a significant improvement of the enophthalmos, the rate of postoperative enophthalmos was significantly increased in cases of only orbital floor repair with PDS foils. Radiologically, a significant reconstruction of the three-dimensional bony orbit succeeded with the simple use of PSIs leading to a significant reduction in the traumatically enlarged orbital volume. PSI also led to a significant reduction in the traumatically enlarged medial angle of the orbit. This was not the case for single-floor repair with PDS foil. The results of this study suggest that complex orbital fractures can be reconstructed at an even higher degree of accuracy with selective laser-melted PSIs than PDS foils. In order to achieve a true to original reconstruction of the bony orbit, surgical treatment of the medial orbital wall can be advocated for in the long term depending on the indication.
- Published
- 2022
- Full Text
- View/download PDF
16. Advances and Innovations in Ablative Head and Neck Oncologic Surgery Using Mixed Reality Technologies in Personalized Medicine.
- Author
-
Karnatz N, Möllmann HL, Wilkat M, Parviz A, and Rana M
- Abstract
The benefit of computer-assisted planning in head and neck ablative and reconstructive surgery has been extensively documented over the last decade. This approach has been proven to offer a more secure surgical procedure. In the treatment of cancer of the head and neck, computer-assisted surgery can be used to visualize and estimate the location and extent of the tumor mass. Nowadays, some software tools even allow the visualization of the structures of interest in a mixed reality environment. However, the precise integration of mixed reality systems into a daily clinical routine is still a challenge. To date, this technology is not yet fully integrated into clinical settings such as the tumor board, surgical planning for head and neck tumors, or medical and surgical education. As a consequence, the handling of these systems is still of an experimental nature, and decision-making based on the presented data is not yet widely used. The aim of this paper is to present a novel, user-friendly 3D planning and mixed reality software and its potential application for ablative and reconstructive head and neck surgery.
- Published
- 2022
- Full Text
- View/download PDF
17. Primary Orbital Reconstruction with Selective Laser Melting (SLM) of Patient-Specific Implants (PSIs): An Overview of 96 Surgically Treated Patients.
- Author
-
Rana M, Moellmann HL, Schorn L, Lommen J, Rana M, Wilkat M, and Hufendiek K
- Abstract
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.
- Published
- 2022
- Full Text
- View/download PDF
18. Analysis of Spontaneous and Induced Osteogenic Differentiation in 3D-micromasses of Human Multipotent Stem Cells.
- Author
-
Lommen J, Sus M, Berr K, Kübler NR, Langenbach F, Sproll C, Wilkat M, Schrader F, Handschel J, and Schorn L
- Subjects
- Ascorbic Acid pharmacology, Dexamethasone, Female, Humans, Male, Multipotent Stem Cells, Proto-Oncogene Proteins c-akt, Osteogenesis, Phosphatidylinositol 3-Kinases
- Abstract
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 β-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 β-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., (Copyright © 2022, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
19. Evaluation of the Fitting Accuracy of CAD/CAM-Manufactured Patient-Specific Implants for the Reconstruction of Cranial Defects-A Retrospective Study.
- Author
-
Moellmann HL, Mehr VN, Karnatz N, Wilkat M, Riedel E, and Rana M
- Abstract
Cranioplasties show overall high complication rates of up to 45.3%. Risk factors potentially associated with the occurrence of postoperative complications are frequently discussed in existing research. The present study examines the positioning of 39 patient-specific implants (PSI) made from polyetheretherketone (PEEK) and retrospectively investigates the relationship between the fitting accuracy and incidence of postoperative complications. To analyze the fitting accuracy of the implants pre- and post-operatively, STL files were created and superimposed in a 3D coordinate system, and the deviations were graphically displayed and evaluated along with the postoperative complications. On average, 95.17% (SD = 9.42) of the measurements between planned and surgically achieved implant position were within the defined tolerance range. In cases with lower accordance, an increased occurrence of complications could not be demonstrated. The overall postoperative complication rate was 64.1%. The fitting of the PEEK-PSI was highly satisfactory. There were predominantly minor deviations of the achieved compared to the planned implant positions; however, estimations were within the defined tolerance range. Despite the overall high accuracy of fitting, a considerable complication rate was found. To optimize the surgical outcome, the focus should instead be directed towards the investigation of other risk factors.
- Published
- 2022
- Full Text
- View/download PDF
20. Comparison of the Accuracy and Clinical Parameters of Patient-Specific and Conventionally Bended Plates for Mandibular Reconstruction.
- Author
-
Möllmann HL, Apeltrath L, Karnatz N, Wilkat M, Riedel E, Singh DD, and Rana M
- Abstract
Objectives: This retrospective study compared two mandibular reconstruction procedures-conventional reconstruction plates (CR) and patient-specific implants (PSI)-and evaluated their accuracy of reconstruction and clinical outcome., Methods: Overall, 94 patients had undergone mandibular reconstruction with CR ( n = 48) and PSI ( n = 46). Six detectable and replicable anatomical reference points, identified via computer tomography, were used for defining the mandibular dimensions. The accuracy of reconstruction was assessed using pre- and postoperative differences., Results: In the CR group, the largest difference was at the lateral point of the condyle mandibulae (D2) -1.56 mm (SD = 3.8). In the PSI group, the largest difference between preoperative and postoperative measurement was shown at the processus coronoid (D5) with +1.86 mm (SD = 6.0). Significant differences within the groups in pre- and postoperative measurements were identified at the gonion (D6) [ t (56) = -2.217; p = .031 <.05]. In the CR group, the difference was 1.5 (SD = 3.9) and in the PSI group -1.04 (SD = 4.9). CR did not demonstrate a higher risk of plate fractures and post-operative complications compared to PSI., Conclusion: For reconstructing mandibular defects, CR and PSI are eligible. In each case, the advantages and disadvantages of these approaches must be assessed. The functional and esthetic outcome of mandibular reconstruction significantly improves with the experience of the surgeon in conducting microvascular grafts and familiarity with computer-assisted surgery. Interoperator variability can be reduced, and training of younger surgeons involved in planning can be reaching better outcomes in the future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Möllmann, Apeltrath, Karnatz, Wilkat, Riedel, Singh and Rana.)
- Published
- 2021
- Full Text
- View/download PDF
21. Advances in the Resection and Reconstruction of Midfacial Tumors Through Computer Assisted Surgery.
- Author
-
Wilkat M, Kübler N, and Rana M
- Abstract
Curatively intended oncologic surgery is based on a residual-free tumor excision. Since decades, the surgeon's goal of R0-resection has led to radical resections in the anatomical region of the midface because of the three-dimensionally complex anatomy where aesthetically and functionally crucial structures are in close relation. In some cases, this implied aggressive overtreatment with loss of the eye globe. In contrast, undertreatment followed by repeated re-resections can also not be an option. Therefore, the evaluation of the true three-dimensional tumor extent and the intraoperative availability of this information seem critical for a precise, yet substance-sparing tumor removal. Computer assisted surgery (CAS) can provide the framework in this context. The present study evaluated the beneficial use of CAS in the treatment of midfacial tumors with special regard to tumor resection and reconstruction. Therefore, 60 patients diagnosed with a malignancy of the upper jaw has been treated, 31 with the use of CAS and 29 conventionally. Comparison of the two groups showed a higher rate of residual-free resections in cases of CAS application. Furthermore, we demonstrate the use of navigated specimen taking called tumor mapping. This procedure enables the transparent, yet precise documentation of three-dimensional tumor borders which paves the way to a more feasible interdisciplinary exchange leading e.g. to a much more focused radiation therapy. Moreover, we evaluated the possibilities of primary midface reconstructions seizing CAS, especially in cases of infiltrated orbital floors. These cases needed reduction of intra-orbital volume due to the tissue loss after resection which could be precisely achieved by CAS. These benefits of CAS in midface reconstruction found expression in positive changes in quality of life. The present work was able to demonstrate that the area of oncological surgery of the midface is a prime example of interface optimization based on the sensible use of computer assistance. The fact that the system makes the patient transparent for the surgeon and the procedure controllable facilitates a more precise and safer treatment oriented to a better outcome., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wilkat, Kübler and Rana.)
- Published
- 2021
- Full Text
- View/download PDF
22. Use and Evaluation of a Computer-Assisted Examination Method for the Diagnosis and Analysis of Medication-Related Osteonecrosis of the Jaw.
- Author
-
Wilkat M, Singh DD, Lutz I, Möllmann H, Gellrich NC, and Rana M
- Abstract
The aim of the present study was to analyze the size of the preoperatively calculated defect volume of MRONJ patients (medication-related osteonecrosis of the jaw) and to develop a computer-aided tool based on techniques of AI (artificial intelligence) that facilitates diagnostics of MRONJ. For this purpose, on the basis of 3D (three-dimensional) data sets of 175 MRONJ patients, the outline of the necrosis was marked with the software iPlan 3.0.5 (BrainLAB AG) thus determining the respective volume. The correlation of this volume with other 31 collected parameters was analyzed retrospectively. There was a significant correlation between the defect volume on the one hand, and the MRONJ stage, the number of performed operations, and the therapy invasiveness on the other hand. Furthermore, it could be shown that in one third of the cases no defects could be recognized in the 2D imaging by panoramic radiograph, while in the 3D data sets defects already had been demarcated. On the basis of these data, a computer-aided tool based on the principles of AI was developed and validated, which might allow the automated calculation of the 3D defect extension and classification of the MRONJ cases into a ranking system. In conclusion, preparation of a 3D image can be recommended for reliably making the diagnosis "MRONJ." Moreover, knowledge of the exact defect volume serves as a decision-making aid with regard to the choice of therapy, ensures intraoperative certitude, and allows an assessment of the prognosis., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2020.)
- Published
- 2021
- Full Text
- View/download PDF
23. Adenosine receptor 2B activity promotes autonomous growth, migration as well as vascularization of head and neck squamous cell carcinoma cells.
- Author
-
Wilkat M, Bast H, Drees R, Dünser J, Mahr A, Azoitei N, Marienfeld R, Frank F, Brhel M, Ushmorov A, Greve J, Goldberg-Bockhorn E, Theodoraki MN, Doescher J, Laban S, Schuler PJ, Hoffmann TK, and Brunner C
- Subjects
- 5'-Nucleotidase biosynthesis, 5'-Nucleotidase metabolism, Adenosine A2 Receptor Antagonists pharmacology, Animals, Apoptosis drug effects, Cell Cycle Checkpoints drug effects, Cell Growth Processes drug effects, Cell Growth Processes physiology, Cell Line, Tumor, Cell Movement drug effects, Cell Movement physiology, Chick Embryo, Chorioallantoic Membrane metabolism, GPI-Linked Proteins biosynthesis, GPI-Linked Proteins metabolism, Head and Neck Neoplasms blood supply, Head and Neck Neoplasms pathology, Humans, Jurkat Cells, Neovascularization, Pathologic metabolism, Neovascularization, Pathologic pathology, Receptor, Adenosine A2B biosynthesis, Squamous Cell Carcinoma of Head and Neck blood supply, Squamous Cell Carcinoma of Head and Neck pathology, Sulfonamides pharmacology, Xanthines pharmacology, Head and Neck Neoplasms metabolism, Receptor, Adenosine A2B metabolism, Squamous Cell Carcinoma of Head and Neck metabolism
- Abstract
Adenosine is a signaling molecule that exerts dual effects on tumor growth: while it inhibits immune cell function and thereby prevents surveillance by the immune system, it influences tumorigenesis directly via activation of adenosine receptors on tumor cells at the same time. However, the adenosine-mediated mechanisms affecting oncogenic processes particularly in head and neck squamous cell carcinomas (HNSCC) are not fully understood. Here, we investigated the role of adenosine receptor activity on HNSCC-derived cell lines. Targeting the adenosine receptor A2B (ADORA2B) on these cells with the inverse agonist/antagonist PSB-603 leads to inhibition of cell proliferation, transmigration as well as VEGFA secretion in vitro. At the molecular level, these effects were associated with cell cycle arrest as well as the induction of the apoptotic pathway. In addition, shRNA-mediated downmodulation of ADORA2B expression caused decreased proliferation. Moreover, in in vivo xenograft experiments, chemical and genetic abrogation of ADORA2B activity impaired tumor growth associated with decreased tumor vascularization. Together, our findings characterize ADORA2B as a crucial player in the maintenance of HNSCC and, therefore, as a potential therapeutic target for HNSCC treatment., (© 2019 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)
- Published
- 2020
- Full Text
- View/download PDF
24. Profiling antibody responses to infections by Chlamydia abortus enables identification of potential virulence factors and candidates for serodiagnosis.
- Author
-
Forsbach-Birk V, Foddis C, Simnacher U, Wilkat M, Longbottom D, Walder G, Benesch C, Ganter M, Sachse K, and Essig A
- Subjects
- Animals, Antibodies, Bacterial immunology, Antigens, Bacterial immunology, Bacterial Proteins immunology, Biomarkers blood, Cell Line, Tumor, Chlamydia Infections blood, Female, HeLa Cells, Humans, Pregnancy, Serum immunology, Sheep, Antibody Formation immunology, Chlamydia immunology, Chlamydia Infections immunology, Virulence Factors immunology
- Abstract
Enzootic abortion of ewes (EAE) due to infection with the obligate intracellular pathogen Chlamydia (C.) abortus is an important zoonosis leading to considerable economic loss to agriculture worldwide. The pathogen can be transmitted to humans and may lead to serious infection in pregnant women. Knowledge about epidemiology, clinical course and transmission to humans is hampered by the lack of reliable diagnostic tools. Immunoreactive proteins, which are expressed in infected animals and humans, may serve as novel candidates for diagnostic marker proteins and represent putative virulence factors. In order to broaden the spectrum of immunogenic C. abortus proteins we applied 2D immunoblot analysis and screening of an expression library using human and animal sera. We have identified 48 immunoreactive proteins representing potential diagnostic markers and also putative virulence factors, such as CAB080 (homologue of the "macrophage infectivity potentiator", MIP), CAB167 (homologue of the "translocated actin recruitment protein", TARP), CAB712 (homologue of the "chlamydial protease-like activity factor", CPAF), CAB776 (homologue of the "Polymorphic membrane protein D", PmpD), and the "hypothetical proteins" CAB063, CAB408 and CAB821, which are predicted to be type III secreted. We selected two putative virulence factors for further characterization, i.e. CAB080 (cMIP) and CAB063, and studied their expression profiles at transcript and protein levels. Analysis of the subcellular localization of both proteins throughout the developmental cycle revealed CAB063 being the first C. abortus protein shown to be translocated to the host cell nucleus.
- Published
- 2013
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.