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Article
Publication date: 25 September 2009

Richard Bibb, Dominic Eggbeer, Peter Evans, Alan Bocca and Adrian Sugar

The computer‐aided design (CAD) and manufacture of custom‐fitting surgical guides have been shown to provide an accurate means of transferring computer‐aided planning to…

Abstract

Purpose

The computer‐aided design (CAD) and manufacture of custom‐fitting surgical guides have been shown to provide an accurate means of transferring computer‐aided planning to surgery. To date guides have been produced using fragile materials via rapid prototyping techniques such as stereolithography (SLA), which typically require metal reinforcement to prevent damage from drill bits. The purpose of this paper is to report case studies which explore the application of selective laser melting (SLM) to the direct manufacture of stainless steel surgical guides. The aim is to ascertain whether the potential benefits of enhanced rigidity, increased wear resistance (negating reinforcement) and easier sterilisation by autoclave can be realised in practice.

Design/methodology/approach

A series of clinical case studies are undertaken utilising medical scan data, CAD and SLM. The material used is 316L stainless steel, an alloy typically used in medical and devices and surgical instruments. All treatments are planned in parallel with existing techniques and all guides are test fitted and assessed on SLA models of the patients' anatomy prior to surgery.

Findings

This paper describes the successful application of SLM to the production of stainless steel surgical guides in four different maxillofacial surgery case studies. The cases reported address two types of procedure, the placement of osseointegrated implants for prosthetic retention and Le Fort 1 osteotomies using internal distraction osteogenesis. The cases reported here have demonstrated that SLM is a viable process for the manufacture of custom‐fitting surgical guides.

Practical implications

The cases have identified that the effective design of osteotomy guides requires further development and refinement.

Originality/value

This paper represents the first reported applications of SLM technology to the direct manufacture of stainless steel custom‐fitting surgical guides. Four successful exemplar cases are described including guides for osteotomy as well as drilling. Practical considerations are presented along with suggestions for further development.

Details

Rapid Prototyping Journal, vol. 15 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 14 January 2014

Yunfeng Liu, Wenqing Liao, Guangsheng Jin, Quanming Yang and Wei Peng

– The purpose is to realize precise apicoectomy with less surgical risk and improved quality and efficiency.

Abstract

Purpose

The purpose is to realize precise apicoectomy with less surgical risk and improved quality and efficiency.

Design/methodology/approach

First, the procedure of precise apicoectomy based on additive manufacturing (AM) and digital design is proposed. With CT images of the patient's oral, a 3D model of alveolar bone and teeth is reconstructed, and based on this model, the infected tissue and enclosed root tip can be determined. Thus, a surgical plan can be created based on clear anatomical relationships and minimal negative constraints, which will then determine the drill position, direction and depth, as well as the resection length of root tip. With this plan, a surgical guide design is performed via a composite model from reversed plaster models and hard tissue models from CT, and accessory tools including drill with stop plane and handle are also selected. With the surgical guide, the virtual plan in the computer can be realized in the clinic.

Findings

With this methodology, the dentist can perform root-end resection with greater accuracy, save more than 30 percent of operatory time, and the discomfort to the patient is reduced to a minimum.

Practical implications

The proposed methodology has been used in ten cases for root-end resections. In fact, this method of designing a computer-based treatment plan with a 3D model of a patient and applying it in the clinic through guiding tools can be used in other surgeries, such as orthognathic surgery or osteotomy.

Originality/value

This case report illustrates that with AM and digital design methods, optimal operational plans can be designed and realized for apicoectomy, and the quality and efficiency of clinical surgery are greatly improved compared with conventional methods.

Details

Rapid Prototyping Journal, vol. 20 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 11 September 2018

Diana Popescu, Dan Laptoiu, Rodica Marinescu and Iozefina Botezatu

This paper aims to fill a research gap by presenting design and 3D printing guidelines and considerations which apply to the development process of patient-specific…

Abstract

Purpose

This paper aims to fill a research gap by presenting design and 3D printing guidelines and considerations which apply to the development process of patient-specific osteotomy guides for orthopaedic surgery.

Design/methodology/approach

Analysis of specific constraints related to patient-specific surgical guides design and 3D printing, lessons learned during the development process of osteotomy guides for orthopaedic surgery, literature review of recent studies in the field and data gathered from questioning a group of surgeons for capturing their preferences in terms of surgical guides design corresponding to precise functionality (materializing cutting trajectories, ensuring unique positioning and stable fixation during surgery), were all used to extract design recommendations.

Findings

General design rules for patient-specific osteotomy guides were inferred from examining each step of the design process applied in several case studies in relation to how these guides should be designed to fulfill medical and manufacturing (fused deposition modelling process) constraints. Literature was also investigated for finding other information than the simple reference that the surgical guide is modelled as negative of the bone. It was noticed that literature is focussed more on presenting and discussing medical issues and on assessing surgical outcomes, but hardly at all on guides’ design and design for additive manufacturing aspects. Moreover, surgeons’ opinion was investigated to collect data on different design aspects, as well as interest and willingness to use such 3D-printed surgical guides in training and surgery.

Practical implications

The study contains useful rules and recommendations for engineers involved in designing and 3D printing patient-specific osteotomy guides.

Originality/value

A synergetic approach to identify general rules and recommendations for the patient-specific surgical guides design is presented. Specific constraints are identified and analysed using three case studies of wrist, femur and foot osteotomies. Recent literature is reviewed and surgeons’ opinion is investigated.

Details

Rapid Prototyping Journal, vol. 24 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 19 October 2015

M. Fantini, F. De Crescenzio, L. Ciocca and F. Persiani

The purpose of this paper is to describe two different approaches for manufacturing pre-formed titanium meshes to assist prosthetically guided bone regeneration of…

Abstract

Purpose

The purpose of this paper is to describe two different approaches for manufacturing pre-formed titanium meshes to assist prosthetically guided bone regeneration of atrophic maxillary arches. Both methods are based on the use of additive manufacturing (AM) technologies and aim to limit at the minimal intervention the bone reconstructive surgery by virtual planning the surgical intervention for dental implants placement.

Design/methodology/approach

Two patients with atrophic maxillary arches were scheduled for bone augmentation using pre-formed titanium mesh with particulate autogenous bone graft and alloplastic material. The complete workflow consists of four steps: three-dimensional (3D) acquisition of medical images and virtual planning, 3D modelling and design of the bone augmentation volume, manufacturing of biomodels and pre-formed meshes, clinical procedure and follow up. For what concerns the AM, fused deposition modelling (FDM) and direct metal laser sintering (DMLS) were used.

Findings

For both patients, a post-operative control CT examination was scheduled to evaluate the progression of the regenerative process and verify the availability of an adequate amount of bone before the surgical intervention for dental implants placement. In both cases, the regenerated bone was sufficient to fix the implants in the planned position, improving the intervention quality and reducing the intervention time during surgery.

Originality/value

A comparison between two novel methods, involving AM technologies are presented as viable and reproducible methods to assist the correct bone augmentation of atrophic patients, prior to implant placement for the final implant supported prosthetic rehabilitation.

Details

Rapid Prototyping Journal, vol. 21 no. 6
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 13 May 2019

Igor Budak, Aleksandar Kiralj, Mario Sokac, Zeljko Santosi, Dominic Eggbeer and Sean Peel

Computer-aided design and additive manufacture (CAD/AM) technologies are sufficiently refined and meet the necessary regulatory requirements for routine incorporation into…

Abstract

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.

Details

Rapid Prototyping Journal, vol. 25 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 10 June 2020

Taehun Kim, Guk Bae Kim, Hyun Kyung Song, Yoon Soo Kyung, Choung-Soo Kim and Namkug Kim

This study aims to systemically evaluate morphological printing errors between computer-aided design (CAD) and reference models fabricated using two different…

Abstract

Purpose

This study aims to systemically evaluate morphological printing errors between computer-aided design (CAD) and reference models fabricated using two different three-dimensional printing (3DP) technologies with hard and soft materials.

Design/methodology/approach

The reference models were designed to ensure simpler and more accurate measurements than those obtained from actual kidney simulators. Three reference models, i.e. cube, dumbbell and simplified kidney, were manufactured using photopolymer jetting (PolyJet) with soft and hard materials and multi-jet printing (MJP) with hard materials. Each reference model was repeatably measured five times using digital calipers for each length. These values were compared with those obtained using CAD.

Findings

The results demonstrate that the cube models with the hard material of MJP and hard and soft materials of PolyJet were smaller (p = 0.022, 0.015 and 0.057, respectively). The dumbbell model with the hard material of MJP was smaller (p = 0.029) and that with the soft material of PolyJet was larger (p = 0.020). However, the dumbbell with the hard material of PolyJet generated low errors (p = 0.065). Finally, the simplified kidney models with the hard material of MJP and soft materials of PolyJet were smaller (p = 0.093 and 0.021) and that with the hard material of PolyJet was opposite to the former models (p = 0.043).

Originality/value

This study, to the best of authors’ knowledge, is the first to determine the accuracy between CAD and reference models fabricated using two different 3DP technologies with multi-materials. Thus, it serves references for surgical applications as simulators and guides that require accuracy.

Details

Rapid Prototyping Journal, vol. 26 no. 7
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 23 January 2007

Arthur Bens, Hermann Seitz, Günter Bermes, Moritz Emons, Andreas Pansky, Barbara Roitzheim, Edda Tobiasch and Carsten Tille

To describe the development of a novel polyether(meth)acrylate‐based resin material class for stereolithography with alterable material characteristics.

Abstract

Purpose

To describe the development of a novel polyether(meth)acrylate‐based resin material class for stereolithography with alterable material characteristics.

Design/methodology/approach

A complete overview of details to composition parameters, the optimization and bandwidth of mechanical and processing parameters is given. Initial biological characterization experiments and future application fields are depicted. Process parameters are studied in a commercial 3D systems Viper stereolithography system, and a new method to determine these parameters is described herein.

Findings

Initial biological characterizations show the non‐toxic behavior in a biological environment, caused mainly by the (meth)acrylate‐based core components. These photolithographic resins combine an adjustable low Young's modulus with the advantages of a non‐toxic (meth)acrylate‐based process material. In contrast to the mostly rigid process materials used today in the rapid prototyping industry, these polymeric formulations are able to fulfill the extended need for a soft engineering material. A short overview of sample applications is given.

Practical implications

These polymeric formulations are able to meet the growing demand for a resin class for rapid manufacturing that covers a bandwidth from softer to stiffer materials.

Originality/value

This paper gives an overview about the novel developed material class for stereolithography and should be therefore of high interest to people with interest in novel rapid manufacturing materials and technology.

Details

Rapid Prototyping Journal, vol. 13 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 3 October 2019

Johari Yap Abdullah, Abdul Manaf Abdullah, Helmi Hadi, Adam Husein and Zainul Ahmad Rajion

This paper aims to compare the automatic segmentation of medical data and conversion to stereolithography (STL) skull models using open-source software versus commercial software.

Abstract

Purpose

This paper aims to compare the automatic segmentation of medical data and conversion to stereolithography (STL) skull models using open-source software versus commercial software.

Design/methodology/approach

Both open-source and commercial software used automatic segmentation and post-processing of the data without user intervention, thus avoiding human error. Detailed steps were provided for comparisons and easier to be repeated by other researchers. The results of segmentation, which were converted to STL format were compared using geometric analysis.

Findings

STL skull models produced using open-source software are comparable with the one produced using commercial software. A comparison of STL skull model produced using InVesalius with STL skull model produced using MIMICS resulted in an average dice similarity coefficient (DSC) of 97.6 ± 0.04 per cent and Hausdorff distance (HD) of 0.01 ± 0.005 mm. Inter-rater study for repeatability on MIMICS software yielded an average DSC of 100 per cent and HD of 0.

Social implications

The application of open-source software will benefit the small research institutions or hospitals to produce and virtualise three-dimensional model of the skulls for teaching or clinical purposes without having to purchase expensive commercial software. It is also easily reproduceable by other researchers.

Originality/value

This study is one of the first comparative evaluations of an open-source software with propriety commercial software in producing accurate STL skull models. Inaccurate STL models can lead to inaccurate pre-operative planning or unfit implant.

Details

Rapid Prototyping Journal, vol. 25 no. 10
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 22 October 2019

Ravishanker Baliga, Sharat K. Rao, Raghuvir Pai, Satish B. Shenoy, Atmananda K. Hegde, Shubham Swaroop and Abhijeet Shetkar

The purpose of this paper is to investigate by means of finite element analysis (FEA), the effect of polyethylene insert thickness and implant material, under axial…

Abstract

Purpose

The purpose of this paper is to investigate by means of finite element analysis (FEA), the effect of polyethylene insert thickness and implant material, under axial loading following TKA.

Design/methodology/approach

The 3D geometric model of bone was processed using the CT scan data by MIMICS (3matic Inc.), package. Implant components were 3D scanned and subsequently 3D modeled using ANSYS Spaceclaim and meshed in Hypermesh (Altair Hyperworks). The assembled, meshed bone-implant model was then input to ABAQUS for FE simulations, considering axial loading.

Findings

Polyethylene insert thickness was found to have very little or no significance (p>0.05) on the mechanical performance, namely, stress, strain and stress shielding of bone-implant system. Implant material was found to have a very significant effect (p<0.05) on the performance parameters and greatly reduced the high stress zones up to 60 percent on the tibial flange region and periprosthetic region of tibia.

Originality/value

Very few FEA studies have been done considering a full bone with heterogeneous material properties, to save computational time. Moreover, four different polyethylene insert thickness with a metal-backed and all-poly tibial tray was considered as the variables affecting the bone-implant system response, under static axial loading. The authors believe that considering a full bone shall lead to more precise outcomes, in terms of the response of bone-implant system, namely, stress, strains and stress shielding in the periprosthetic region, to loading.

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 15 August 2019

Diana Popescu, Aurelian Zapciu, Cristian Tarba and Dan Laptoiu

This paper aims to propose a new solution for producing customized three-dimensional (3D)-printed flat-shaped splints, which are then thermoformed to fit the patient’s…

Abstract

Purpose

This paper aims to propose a new solution for producing customized three-dimensional (3D)-printed flat-shaped splints, which are then thermoformed to fit the patient’s hand. The splint design process is automated and is available to clinicians through an online application.

Design/methodology/approach

Patient anthropometric data measured by clinicians are associated with variables of parametric 3D splint models. Once these variables are input by clinicians in the online app, customized stereo lithography (STL) files for both splint and half mold, in the case of the bi-material splint, are automatically generated and become available for download. Bi-materials splints are produced by a hybrid manufacturing process involving 3D printing and overmolding.

Findings

This approach eliminates the need for 3D CAD-proficient clinicians, allows fast generation of customized splints, generates two-dimensional (2D) drawings of splints for verifying shape and dimensions before 3D printing and generates the STL files. Automation reduces splint design time and cost, while manufacturing time is diminished by 3D printing the splint in a flat position.

Practical implications

The app could be used in clinical practice. It meets the demands of mass customization using 3D printing in a field where individualization is mandatory. The solution is scalable – it can be extended to other splint designs or to other limbs. 3D-printed tailored splints can offer improved wearing comfort and aesthetic appearance, while maintaining hand immobilization, allowing visually controlled follow-up for edema and rapidly observing the need for revision if necessary.

Originality/value

An online application was developed for uploading patient measurements and downloading 2D drawings and STL files of customized splints. Different models of splints can be designed and included in the database as alternative variants. A method for producing bi-materials flat splints combining soft and rigid polymers represents another novelty of the research.

Details

Rapid Prototyping Journal, vol. 26 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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