scholarly journals The Recent Revolution in the Design and Manufacture of Cranial Implants

Neurosurgery ◽  
2015 ◽  
Vol 77 (5) ◽  
pp. 814-824 ◽  
Author(s):  
David J. Bonda ◽  
Sunil Manjila ◽  
Warren R. Selman ◽  
David Dean

AbstractLarge format (ie, >25 cm2) cranioplasty is a challenging procedure not only from a cosmesis standpoint, but also in terms of ensuring that the patient's brain will be well-protected from direct trauma. Until recently, when a patient's own cranial flap was unavailable, these goals were unattainable. Recent advances in implant computer-aided design and 3-dimensional (3-D) printing are leveraging other advances in regenerative medicine. It is now possible to 3-D-print patient-specific implants from a variety of polymer, ceramic, or metal components. A skull template may be used to design the external shape of an implant that will become well integrated in the skull, while also providing beneficial distribution of mechanical force in the event of trauma. Furthermore, an internal pore geometry can be utilized to facilitate the seeding of banked allograft cells. Implants may be cultured in a bioreactor along with recombinant growth factors to produce implants coated with bone progenitor cells and extracellular matrix that appear to the body as a graft, albeit a tissue-engineered graft. The growth factors would be left behind in the bioreactor and the graft would resorb as new host bone invades the space and is remodeled into strong bone. As we describe in this review, such advancements will lead to optimal replacement of cranial defects that are both patient-specific and regenerative.

2020 ◽  
Vol 9 (3) ◽  
pp. 832 ◽  
Author(s):  
Dave Chamo ◽  
Bilal Msallem ◽  
Neha Sharma ◽  
Soheila Aghlmandi ◽  
Christoph Kunz ◽  
...  

The use of patient-specific implants (PSIs) in craniofacial surgery is often limited due to a lack of expertise and/or production costs. Therefore, a simple and cost-efficient template-based fabrication workflow has been developed to overcome these disadvantages. The aim of this study is to assess the accuracy of PSIs made from their original templates. For a representative cranial defect (CRD) and a temporo-orbital defect (TOD), ten PSIs were made from polymethylmethacrylate (PMMA) using computer-aided design (CAD) and three-dimensional (3D) printing technology. These customized implants were measured and compared with their original 3D printed templates. The implants for the CRD revealed a root mean square (RMS) value ranging from 1.128 to 0.469 mm with a median RMS (Q1 to Q3) of 0.574 (0.528 to 0.701) mm. Those for the TOD revealed an RMS value ranging from 1.079 to 0.630 mm with a median RMS (Q1 to Q3) of 0.843 (0.635 to 0.943) mm. This study demonstrates that a highly precise duplication of PSIs can be achieved using this template-molding workflow. Thus, virtually planned implants can be accurately transferred into haptic PSIs. This workflow appears to offer a sophisticated solution for craniofacial reconstruction and continues to prove itself in daily clinical practice.


2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
D G E Thiem ◽  
B Al-Nawas ◽  
P W Kämmerer

Abstract In recent years, alloplastic temporomandibular joint (TMJ) replacement has become a permissible procedure for the reconstruction of severely destroyed TMJs. The use of computer-aided design/computer-aided manufacturing (CAD/CAM) has extended the range of applications to complex anatomical situations. The aim of the treatment is to improve the usually restricted mouth opening and thus oral hygiene and nutrition, which leads to a regular improvement in the general quality of life. The following case report describes the bilateral replacement of ankylotically destroyed TMJs using patient-specific endoprostheses with simultaneous displacement of the maxilla. Innovative in the case described is the impression-free CAD/CAM planning, whereby the upper and lower prostheses were produced on the basis of 3D printed patient models.


Author(s):  
L Q Tang ◽  
D N Moreton

The timing scroll is an important feeding mechanism on packaging lines. As packaging line speeds have increased and the shape of containers has become more diverse, the techniques used for the design and manufacture of such timing scrolls have become critical for successful packaging line performance. Since 1980, various techniques have evolved to improve scroll design, manufacture and the associated line performance. In recent years, as CAD (computer aided design), CAM (computer aided manufacture) and CNC (computer numerical control) techniques have evolved, scroll design and manufacturing techniques began to be linked with computer techniques. In this paper, a scroll design and manufacturing package is presented which can be run on a minicomputer, such as a μ-VAX on an IBM PC clone. This scroll package can produce a timing scroll for any type of container with a correct pocket shape and good dynamic characteristic. Tests using carefully chosen containers have been made using this package and the results indicate that the scrolls obtained by this package have the correct pocket shape and good line performance. However, the design of a good pick-up geometry for some container shapes remains a problem.


1991 ◽  
Vol 13 (1) ◽  
pp. 3-9 ◽  
Author(s):  
R. Torres-Moreno ◽  
C.G. Saunders ◽  
J. Foort ◽  
J.B. Morrison

Author(s):  
S. Minami ◽  
T. Ishida ◽  
S. Yamamoto ◽  
K. Tomita ◽  
M. Odamura

Abstract A concept for the initial stage of the mechanical design and its implementation in the computer-aided design (CAD) are presented. The process of decision making in design is: (1) determining an outline of the whole assembly using a 2-dimensional model that is easy to operate; (2) checking the outline using a 3-dimensional model in which it is easy to identify the spatial relationships; (3) determining details of its sub-assemblies or their components using the 2-dimensional model; and (4) checking the details using the 3-dimensional model. The CAD system must provide consistent relationships through all the steps. For that, following functions are implemented in our prototype system: (1) a 2D and 3D integrated model for consistency between 2- and 3-dimensional shapes, (2) a hierarchical assembly model with dimensional constraints for consistency within an assembly and their components, and (3) a check on constraints for consistency between shapes and designers’ intentions. As a result, the system can provide an environment well fitted to the designers’ decision making process.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Boyoung Kim ◽  
Minyong Choi ◽  
Seung-Woo Son ◽  
Deokwon Yun ◽  
Sukjune Yoon

Purpose Many manufacturing sites require precision assembly. Particularly, similar to cell phones, assembly at the sub-mm scale is not easy, even for humans. In addition, the system should assemble each part with adequate force and avoid breaking the circuits with excessive force. The purpose of this study is to assemble high precision components with relatively reasonable vision devices compared to previous studies. Design/methodology/approach This paper presents a vision-force guided precise assembly system using a force sensor and two charge coupled device (CCD) cameras without an expensive 3-dimensional (3D) sensor or computer-aided design model. The system accurately estimates 6 degrees-of-freedom (DOF) poses from a 2D image in real time and assembles parts with the proper force. Findings In this experiment, three connectors are assembled on a printed circuit board. This system obtains high accuracy under 1 mm and 1 degree error, which shows that this system is effective. Originality/value This is a new method for sub-mm assembly using only two CCD cameras and one force sensor.


2020 ◽  
Vol 162 (3) ◽  
pp. 343-345
Author(s):  
Vilija J. Vaitaitis ◽  
Michael E. Dunham ◽  
Yong-Chan Kwon ◽  
Wyatt C. Mayer ◽  
Adele K. Evans ◽  
...  

We describe a device engineered for realistic simulation of myringotomy and tympanostomy tube insertion that tracks instrument placement and objectively measures operator proficiency. A 3-dimensional computer model of the external ear and cartilaginous external auditory canal was created from a normal maxillofacial computed tomography scan, and models for the bony external auditory canal and tympanic cavity were created with computer-aided design software. Physical models were 3-dimensionally printed from the computer reconstructions. The external auditory canal and tympanic cavity surfaces were coated with conductive material and wired to a capacitive sensor interface. A programmable microcontroller with custom embedded software completed the system. Construct validation was completed by comparing the run times and total sensor contact times of otolaryngology faculty and residents.


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