scholarly journals Computer-aided methods for single-stage fibrous dysplasia excision and reconstruction in the zygomatico-orbital complex

2019 ◽  
Vol 25 (4) ◽  
pp. 728-737 ◽  
Author(s):  
Igor Budak ◽  
Aleksandar Kiralj ◽  
Mario Sokac ◽  
Zeljko Santosi ◽  
Dominic Eggbeer ◽  
...  
Keyword(s):  
Fibrous Dysplasia ◽  
Single Stage ◽  
Successful Outcome ◽  
Patient Specific ◽  
Additive Manufacture ◽  
Maximum Deviation ◽  
Design Guideline ◽  
Design Decisions ◽  
Content Type ◽  
Computer Aided

Purpose Computer-aided design and additive manufacture (CAD/AM) technologies are sufficiently refined and meet the necessary regulatory requirements for routine incorporation into the medical field, with long-standing application in surgeries of the maxillofacial and craniofacial regions. They have resulted in better medical care for patients and faster, more accurate procedures. Despite ever-growing evidence about the advantages of computer-aided planning, CAD and AM in surgery, detailed reporting on critical design decisions that enable methodological replication and the development and establishment of guidelines to ensure safety are limited. This paper aims to present a novel application of CAD and AM to a single-stage resection and reconstruction of fibrous dysplasia in the zygoma and orbit. Design/methodology/approach It is reported in sufficient fidelity to permit methods replication and design guideline developments in future cases, wherever they occur in the world. The collaborative approach included engineers, designers, surgeons and prosthetists to design patient-specific cutting guides and a custom implant. An iterative design process was used, until the desired shape and function were achieved, for both of the devices. The surgery followed the CAD plan precisely and without problems. Immediate post-operative subjective clinical judgements were of an excellent result. Findings At 19 months post-op, a CT scan was undertaken to verify the clinical and technical outcomes. Dimensional analysis showed maximum deviation of 4.73 mm from the plan to the result, while CAD-Inspection showed that the deviations ranged between −0.1 and −0.8 mm and that the majority of deviations were located around −0.3 mm. Originality/value Improvements are suggested and conclusions drawn regarding the design decisions considered critical to a successful outcome for this type of procedure in the future.

scholarly journals A CAD and AM process for maxillofacial prostheses bar-clip retention

2016 ◽  
Vol 22 (1) ◽  
pp. 170-177 ◽  
Author(s):  
Steffan Daniel ◽  
Dominic Eggbeer
Keyword(s):  
Computer Aided Design ◽  
Laser Scanning ◽  
Retention Mechanism ◽  
Additive Manufacture ◽  
Major Step ◽  
Content Type ◽  
Retention Mechanisms ◽  
Computer Aided ◽  
Patient Consultation ◽  
Consultation Time

Purpose – This paper aims to present novel techniques for designing maxillofacial prostheses using computer-aided design (CAD) and additive manufacture (AM), focusing on the integration of osseointegrated retention components. A fully computer-aided approach is considered as a major step towards reducing patient consultation time and an efficient workflow. Design/methodology/approach – The workflow was illustrated through a phantom model. 3D laser scanning was used to capture the phantom anatomy and pre-fabricated geometric features, which enabled the implant positions to be precisely reverse engineered in the data. A novel CAD workflow was used to design the retention mechanisms and a mould. The individual components were fabricated using AM. A definitive silicone prosthesis that incorporated a bar/clip retention mechanism was then fabricated. Findings – The research demonstrated that retention components can be integrated into prostheses using appropriate CAD and AM technologies. Originality/value – This study demonstrates the feasibility of a computer-aided workflow for designing facial prostheses that incorporate osseointegrated retention mechanisms. Novel techniques were developed to: digitise abutment details using custom scanning locators; design retention components; manufacture retention components using AM; integrate retention components into a CAD and AM prosthesis mould. This overcomes limitations identified in previously published cases and demonstrated significant potential to reduce patient consultation time and create a clinically viable process.

Design, additive manufacture and clinical application of a patient-specific titanium implant to anatomically reconstruct a large chest wall defect

2021 ◽  
Vol 27 (2) ◽  
pp. 304-310
Author(s):  
Alba Gonzalez Alvarez ◽  
Peter Ll. Evans ◽  
Lawrence Dovgalski ◽  
Ira Goldsmith
Keyword(s):  
Chest Wall ◽  
Development Process ◽  
Patient Specific ◽  
Computer Assisted ◽  
Design Guideline ◽  
Wall Defect ◽  
Content Type ◽  
Chest Wall Defect ◽  
Paradoxical Movement ◽  
Custom Made

Purpose Chest wall reconstruction of large oncological defects following resection is challenging. Traditional management involves the use of different materials that surgeons creatively shape intraoperatively to restore the excised anatomy. This is time-consuming, difficult to mould into shape and causes some complications such as dislocation or paradoxical movement. This study aims to present the development and clinical implantation of a novel custom-made three-dimensional (3D) laser melting titanium alloy implant that reconstructs a large chest wall resection and maintains the integrity of the thoracic cage. Design/methodology/approach The whole development process of the novel implant is described: design specifications, computed tomography (CT) scan manipulation, 3D computer-assisted design (CAD), rapid prototyping, final manufacture and clinical implantation. A multidisciplinary collaboration in between engineers and surgeons guided the iterative design process. Findings The implant provided excellent aesthetical and functional results. The virtual planning and production of the implant prior to surgery reduced surgery time and uncertainty. It also improved safety and accuracy. The implant sited nicely on the patient anatomy after resection following the virtual plan. At six months following implantation, there were no implant-related complications of pain, infection, dislocation or paradoxical movement. This technique offered a fast lead-time for implant production, which is crucial for oncological treatment. Research limitations/implications More cases and a long-term follow-up are needed to confirm and quantify the benefits of this procedure; further research is also required to design a solution that better mimics the chest wall biomechanics while preventing implant complications. Originality/value The authors present a novel custom thoracic implant that provided a satisfactory reconstruction of a large chest wall defect, developed and implanted within three weeks to address a fast-growing chondrosarcoma. Furthermore, the authors describe its development process in detail as a design guideline, discussing potential improvements and critical design considerations so that this study can be replicated for future cases.

3D modelling and printing of craniofacial implant template

2019 ◽  
Vol 25 (2) ◽  
pp. 397-403 ◽  
Author(s):  
Deepkamal Kaur Gill ◽  
Kartikeya Walia ◽  
Aditi Rawat ◽  
Divya Bajaj ◽  
Vipin Kumar Gupta ◽  
...  
Keyword(s):  
Bone Cement ◽  
Computer Aided Design ◽  
3D Modelling ◽  
Patient Specific ◽  
3D Design ◽  
Time Saving ◽  
Content Type ◽  
Cranial Defect ◽  
Computer Aided ◽  
Cad Cam

Purpose To relieve intracranial pressure and save patient inflicted with severe head injury, neurosurgeons restore cranial defects. These defects can be caused because of trauma or diseases (Osteomyelitis of bone) which are treated by cranioplasty, using the preserved bone of patient. In case of non-availability of bone, a cranial implant is generated using a biocompatible synthetic material, but this process is less accurate and time-consuming. Hence, this paper aims to present the use of rapid prototyping technology that allows the development of a more accurate patient-specific template and saves the surgery time. Design/methodology/approach A five-year-old girl patient having cranial defect was taken up for cranioplasty. CT (computed tomography) scans of the patient were used to generate 3D design of the implant suitable to conceal the defect on the left frontal portion using CAD/CAM (computer-aided design/ computer-aided manufacturing) software. The design was used for 3D printing to manufacture a base template, which was finally used to fabricate the actual implant using Simplex® P bone cement material to conceal the defect. Findings Surgery using Simplex® P implant was performed successfully on the patient, giving precise natural curvature to left frontal portion of the patient, decreasing surgery time by about 30 per cent. Originality/value The case demonstrates the development of a convenient, time-saving and aesthetically superior digital procedure to treat cranial defect in the absence of preserved bone flap using CT scan as input. 3D modelling and printing were deployed to produce an accurate template which was used to generate an implant using bone cement biocompatible material.

Additive manufacturing for repairing: from damage identification and modeling to DLD

2020 ◽  
Vol 26 (5) ◽  
pp. 929-940 ◽  
Author(s):  
Matteo Perini ◽  
Paolo Bosetti ◽  
Nicolae Balc
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Numerical Control ◽  
Maximum Deviation ◽  
Solid Model ◽  
Content Type ◽  
Geometrical Properties ◽  
Tool Paths ◽  
Direct Laser ◽  
Computer Aided

Purpose This paper aims to decrease the cost of repairing operations, of the damaged mechanical components, by enabling the strong automation of the process and the reduction of manual labor. The main purpose of the hybrid repair process is to restore the original shape of the mechanical parts, by adding and removing material according to the mismatch between the damaged object and the virtual model, to restore its geometrical properties. Design/methodology/approach The DUOADD software tool translates the information collected from a 3D scanner into a digital computer aided design solid model, which can be manipulated through Siemens NX computer aided manufacturing (CAM), to obtain the tool paths, for the Direct Laser Deposition (DLD) technology. DUOADD uses octrees to effectively analyze the damaged region of the mechanical part and then to discretize the volume to be added to export CAM-compatible information as a 3D model, for additive operations. Findings DUOADD is the missing link between two valuable existing technologies, 3D scan and CAM for additive manufacturing, which can now be connected together, to perform automatic repairing. Research limitations/implications A trade-off between resolution and computational effort needs to be achieved. Practical implications DUOADD output is a STEP file, transferred to the CAM software to create the additive and the milling tool paths. The maximum deviation was 40 micrometers, as compared with the original solid model. Originality/value The paper presents a new procedure and new software tools (DUOADD), for the automation of damaged objects restoration process. DUOADD software provides suitable data for using a 5-axis computer numerical control (CNC) milling machine equipped with a DLD tool.

3D Printing & Pharmaceutical Manufacturing: Opportunities and Challenges

2016 ◽  
Vol 5 (01) ◽  
pp. 4723 ◽  
Author(s):  
Bhusnure O. G.* ◽  
Gholve V. S. ◽  
Sugave B. K. ◽  
Dongre R. C. ◽  
Gore S. A. ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Tissue Engineering ◽  
3D Printing ◽  
Computer Aided Design ◽  
Patient Specific ◽  
Computer Design ◽  
3D Scaffolds ◽  
Engineering Research ◽  
Advantages And Disadvantages ◽  
Computer Aided

Many researchers have attempted to use computer-aided design (C.A.D) and computer-aided manufacturing (CAM) to realize a scaffold that provides a three-dimensional (3D) environment for regeneration of tissues and organs. As a result, several 3D printing technologies, including stereolithography, deposition modeling, inkjet-based printing and selective laser sintering have been developed. Because these 3D printing technologies use computers for design and fabrication, and they can fabricate 3D scaffolds as designed; as a consequence, they can be standardized. Growth of target tissues and organs requires the presence of appropriate growth factors, so fabrication of 3Dscaffold systems that release these biomolecules has been explored. A drug delivery system (D.D.S) that administrates a pharmaceutical compound to achieve a therapeutic effect in cells, animals and humans is a key technology that delivers biomolecules without side effects caused by excessive doses. 3D printing technologies and D. D. Ss have been assembled successfully, so new possibilities for improved tissue regeneration have been suggested. If the interaction between cells and scaffold system with biomolecules can be understood and controlled, and if an optimal 3D tissue regenerating environment is realized, 3D printing technologies will become an important aspect of tissue engineering research in the near future. 3D Printing promises to produce complex biomedical devices according to computer design using patient-specific anatomical data. Since its initial use as pre-surgical visualization models and tooling molds, 3D Printing has slowly evolved to create one-of-a-kind devices, implants, scaffolds for tissue engineering, diagnostic platforms, and drug delivery systems. Fuelled by the recent explosion in public interest and access to affordable printers, there is renewed interest to combine stem cells with custom 3D scaffolds for personalized regenerative medicine. Before 3D Printing can be used routinely for the regeneration of complex tissues (e.g. bone, cartilage, muscles, vessels, nerves in the craniomaxillofacial complex), and complex organs with intricate 3D microarchitecture (e.g. liver, lymphoid organs), several technological limitations must be addressed. Until recently, tablet designs had been restricted to the relatively small number of shapes that are easily achievable using traditional manufacturing methods. As 3D printing capabilities develop further, safety and regulatory concerns are addressed and the cost of the technology falls, contract manufacturers and pharmaceutical companies that experiment with these 3D printing innovations are likely to gain a competitive edge. This review compose the basics, types & techniques used, advantages and disadvantages of 3D printing

New German design guideline for single stage activated sludge plants

2000 ◽  
Vol 41 (9) ◽  
pp. 139-145
Author(s):  
R. Kayser
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Design Procedure ◽  
Single Stage ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Design Guideline

The German design guideline A 131 “Design of single stage activated sludge plants” was amended in 1999. The main changes of the guideline from 1991 are outlined. The design procedure for plants with nitrogen and phosphorus removal is presented.

scholarly journals Indwelling Device-Associated Biofilms in Critically Ill Cancer Patients—Study Protocol

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 306
Author(s):  
Olguta Lungu ◽  
Ioana Grigoras ◽  
Olivia Simona Dorneanu ◽  
Catalina Lunca ◽  
Teodora Vremera ◽  
...  
Keyword(s):  
Cancer Patients ◽  
Critically Ill ◽  
Pathogen Detection ◽  
Venous Catheter ◽  
Successful Outcome ◽  
Patient Specific ◽  
Clinical Value ◽  
Current Standard ◽  
Sepsis Management ◽  
Microorganism Identification

Health care-associated infections are a leading cause of inpatient complications. Rapid pathogen detection/identification is a major challenge in sepsis management that highly influences the successful outcome. The current standard of microorganism identification relies on bacterial growth in culture, which has several limitations. Gene sequencing research has developed culture-independent techniques for microorganism identification, with the aim to improve etiological diagnosis and, therefore, to change sepsis outcome. A prospective, observational, non-interventional, single-center study was designed that assesses biofilm-associated pathogens in a specific subpopulation of septic critically ill cancer patients. Indwelling device samples will be collected in septic patients at the moment of the removal of the arterial catheter, central venous catheter, endotracheal tube and urinary catheter. Concomitantly, clinical data regarding 4 sites (nasal, pharyngeal, rectal and skin) of pathogen colonization at the time of hospital/intensive care admission will be collected. The present study aims to offer new insights into biofilm-associated infections and to evaluate the infection caused by catheter-specific and patient-specific biofilm-associated pathogens in association with the extent of colonization. The analysis relies on the two following detection/identification techniques: standard microbiological method and next generation sequencing (NGS). Retrospectively, the study will estimate the clinical value of the NGS-based detection and its virtual potential in changing patient management and outcome, notably in the subjects with missing sepsis source or lack of response to anti-infective treatment.

Design of the variable frequency oscillator in DC-DC converter

Circuit World ◽  
2019 ◽  
Vol 45 (2) ◽  
pp. 80-85
Author(s):  
Tian Lei ◽  
Nan Gong ◽  
Li Wang ◽  
Qin Qin Li ◽  
Heng Wei Wang
Keyword(s):  
Supply Voltage ◽  
Operating Frequency ◽  
Maximum Deviation ◽  
Variable Frequency ◽  
Cmos Process ◽  
Power Supply Voltage ◽  
Output Stage ◽  
Content Type ◽  
Oscillator Frequency ◽  
Light Load

Purpose Because of the logic delay in the converter, the minimum turn on time of the switch is influenced by the constant time. When the inductor current gets to the threshold of the chip, the control signal will delay for a period. This makes the inductor current rising with the increasing of the clock and leads to the load current out of control. Thus, this paper aims to design an oscillator with a variable frequency protection function. Design/methodology/approach This paper presents an oscillator with the reducing frequency applied in the DC-DC converter. When the converter works normally, the operating frequency of the oscillator is 1.5 MHz. So the inductor current has enough time to decay and prevent the power transistor damaging. After the abnormal condition, the converter returns to the normal operating mode automatically. Findings Based on 0.5 µm CMOS process, simulated by the HSPICE, the simulation results shows that the frequency of the oscillator linearly decreases from 1.5 MHz to 380 KHz when the feedback voltage less than 0.2 V. The maximum deviation of the oscillator frequency is only 6 per cent from −50°C to 125°C within the power supply voltage of 2.7-5.5 V. Originality/value When the light load occurs at the output stage, the oscillator frequency will decrease as the load voltage drops. The test results shows that when the circuit works in the normal condition, the oscillator frequency is 1.5 MHz. When the load decreased, the operating frequency is dropped dramatically.

Monostotic fibrous dysplasia of the thoracic spine: clinopathological description and follow up

2004 ◽  
Vol 100 (4) ◽  
pp. 378-381 ◽  
Author(s):  
Mehmet Arazi ◽  
Onder Guney ◽  
Mustafa Ozdemir ◽  
Omer Uluoglu ◽  
Nuket Uzum
Keyword(s):  
Fibrous Dysplasia ◽  
Thoracic Spine ◽  
Histopathological Examination ◽  
En Bloc Resection ◽  
Spinal Tumors ◽  
En Bloc ◽  
Content Type ◽  
Thoracic Spinal ◽  
Fine Print

✓ The authors report the case of a 53-year-old woman with monostotic fibrous dysplasia of the thoracic spine. The patient presented with a 1-month history of pain in the thoracic spinal region. En bloc resection of the lesion was successfully performed via a transthoracic approach, and a histopathological examination confirmed the diagnosis of fibrous dysplasia. At 24-month follow-up examination, pain and vertebral instability were absent. The findings in this case illustrate that, although very rare, monostotic fibrous dysplasia of the thoracic spine should be considered in the differential diagnosis of spinal tumors. Although a consensus for management of this disease has not been achieved, the authors recommend radical removal of all involved bone as well as internal fixation or bone graft—assisted fusion to achieve long-term stabilization.

A novel parameterized digital-mask generation method for projection stereolithography in tissue engineering

2018 ◽  
Vol 24 (6) ◽  
pp. 935-944 ◽  
Author(s):  
Mingke Li ◽  
Wangyu Liu
Keyword(s):  
Computer Aided Design ◽  
Boundary Region ◽  
Additive Manufacture ◽  
3D Scaffold ◽  
Content Type ◽  
Parameterized Design ◽  
High Efficient ◽  
Unit Cells ◽  
Conventional Methods ◽  
Projection Stereolithography

PurposeThe purpose of this paper is to present the novel parameterized digital-mask generation method which is aimed at enhancing bio-scaffold’s fabricating efficiency with digital micro-mirror device (DMD)-based systems.Design/methodology/approachA method to directly generate the digital masks of bio-scaffolds without modeling the entire 3D scaffold models is presented. In most of the conventional methods, it is inefficient to dynamically modify the size of the structural unit cells during design, because it relies more or less on commercial computer aided design (CAD) platforms. The method proposed in this paper can achieve high efficient parameterized design, and it is independent from any CAD platforms. The generated masks in binary bitmap format can be used by the DMD-based to achieve scaffold’s additive manufacture. In conventional methods, the Boolean operation of the external surface and the internal architectures would result in the damage of unit cells in boundary region. These damaged unit cells not only lose its original mechanical property but also cause numbers of gaps and isolated features that would reduce the geometric accuracy of the fabricated scaffolds; the proposed method in this paper provides an approach to tackle this defect.FindingsThe results show that the proposed method can improve the digital masks generation efficiency.Practical implicationsThe proposed method can serve as an effective supplement to the slicing method in additive manufacture. It also provides a way to design and fabricate scaffolds with heterogeneous architectures.Originality/valueThis paper gives supports to fabricate bio-scaffold with DMD-based systems.

Sign in / Sign up

Export Citation Format

Share Document