Technical report: Rapid intraoperative reconstruction of cranial implants using additively manufactured moulds

2020 ◽  
Vol 234 (9) ◽  
pp. 1011-1017
Author(s):  
Katherine Beaulieu ◽  
Ryan Alkins ◽  
Randy E Ellis ◽  
Manuela Kunz
Keyword(s):  
Rapid Prototyping ◽  
Ad Hoc ◽  
Patient Specific ◽  
Bone Implants ◽  
Reconstruction Accuracy ◽  
Skull Reconstruction ◽  
Technical Report ◽  
Custom Software ◽  
Cranial Implants ◽  
Gain Access

During craniotomies, a portion of the calvarium or skull is removed to gain access to the intracranial space. When it is not possible to re-implant the flap, surgeons may repair the defect intraoperatively or at a later date. With larger defects being more difficult to repair intraoperatively, we investigated a method for the creation of patient-specific moulds for ad hoc bone flap reconstruction using rapid prototyping. Patient-specific moulds were created based on light scanned models of the defect, using custom software and rapid prototyping. Polymethylmethacrylate bone implants were created for three retrospective craniotomy cases and evaluated based on original flap and skull reconstruction accuracy. Bone implants created using our moulding method reconstruct the original flap and skull with an average reconstruction accuracy of 0.82 and 1.3 mm, respectively. Average skull reconstruction accuracy obtained by surgeons performing freehand implant reconstruction was 1.49 mm. Time needed to generate moulds was between 2 h and 45 min and 6 h and 20 min. Improvements to current printing technology will make this procedure technically feasible for future cranial procedures.

scholarly journals P.120 Rapid intraoperative reconstruction of cranial implants for craniotomy procedures: a feasibility study

2019 ◽  
Vol 46 (s1) ◽  
pp. S45
Author(s):  
K Beaulieu ◽  
M Kunz ◽  
R Alkins
Keyword(s):  
Imaging Modality ◽  
Bone Flap ◽  
Patient Specific ◽  
Great Promise ◽  
Surface Model ◽  
Bone Implants ◽  
Scanning Time ◽  
Rapid Generation ◽  
Cranial Implants ◽  
Cost Efficient

Background: The aim of this study was to investigate intraoperative methods to generate patient-specific PMMA bone implants during a craniotomy. The proposed methods combine a cost-efficient, and non-invasive structured light scanner (SLS) as an imaging modality and a prototype printer for rapid generation of implant molds. Methods: This simulation study was performed using retrospective data from three craniotomy patients. The extracted bone flap and the cranial defect were scanned using a SLS, which generates a 3D surface model of an object by projecting a series of light-patterns on it. Prototype printed implant models were generated using two different techniques. The molds were then used to shape PMMA bone implants. These implants were evaluated regarding their accuracy to reconstruct the natural skull anatomy and compared to freehand formed implants. Results: The patient-specific bone implants reconstructed the preoperative anatomy with an average RMS error of 1.37mm (StDev 0.27), compared to an error of 1.5mm (StDev 0.43) for the freehand shaped implants. On average the intraoperative scanning time was 4.7min. The average time to generate and print the implant molds was 204 min. Conclusions: Results of this study have shown great promise for the proposed method to be used for patient-specific bone flap reconstruction during craniotomies.

Mechanical meta-material-based polymer skin graft production by rapid prototyping and replica method

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohamad Attar ◽  
Seher Selen Aydin ◽  
Aliye Arabaci ◽  
Ilven Mutlu
Keyword(s):  
Elastic Modulus ◽  
Rapid Prototyping ◽  
Skin Graft ◽  
Patient Specific ◽  
Skin Grafts ◽  
Content Type ◽  
Patient Specific Implants ◽  
Cranial Implant ◽  
Liquid Silicone ◽  
Cranial Implants

Purpose The purpose of this paper is the production of mechanical meta-material samples by rapid prototyping (RP) and replica technique for patient-specific skin graft or cranial implant applications in tissue engineering. Design/methodology/approach Positive moulds (patterns) were produced by stereolithography-based RP. Impression moulding method was used for the production of silicone products (skin grafts). Alginate was used as a moulding material (negative mould). Room temperature vulcanising silicone was poured into the cavity of alginate mould and then products were produced. TiO2 powder and carbon fibres were used as reinforcement. Meta-material structured polyurethane reinforced silicone composites were also produced. Liquid components (diisocyanate and polyol) were poured into the mould and then polyurethane was produced. Then, polyurethane was immersed in the liquid silicone. Findings It is found that non-destructive ultrasonic test is a fast and reliable method. Meta-material-based composites show dome-shaped tensile/synclastic surface properties which are important for the skin graft and cranial implants. Increasing the amounts of cross-linking agent and TiO2 particles increased the hardness and elastic modulus. Carbon fibre addition enhanced the elastic modulus. Originality/value Although there are studies on the meta-materials, there is limited study on the RP of the meta-materials for patient-specific implants (skin grafts). Auxetic surface shows perfect fit to curved surface of the skull. Although there are studies on the silicone and polyurethane composites, there is limited study on the characterisation of mechanical properties by ultrasonic tests and strain gauge analysis.

scholarly journals 3D MODELLING AND RAPID PROTOTYPING FOR CARDIOVASCULAR SURGICAL PLANNING – TWO CASE STUDIES

2016 ◽  
Vol XLI-B5 ◽  
pp. 887-893 ◽  
Author(s):  
E. Nocerino ◽  
F. Remondino ◽  
F. Uccheddu ◽  
M. Gallo ◽  
G. Gerosa
Keyword(s):  
3D Printing ◽  
Rapid Prototyping ◽  
Case Studies ◽  
Surgical Planning ◽  
Heart Diseases ◽  
Coronary Vessels ◽  
3D Modelling ◽  
Patient Specific ◽  
Surface Model ◽  
Medical Imagery

In the last years, cardiovascular diagnosis, surgical planning and intervention have taken advantages from 3D modelling and rapid prototyping techniques. The starting data for the whole process is represented by medical imagery, in particular, but not exclusively, computed tomography (CT) or multi-slice CT (MCT) and magnetic resonance imaging (MRI). On the medical imagery, regions of interest, i.e. heart chambers, valves, aorta, coronary vessels, etc., are segmented and converted into 3D models, which can be finally converted in physical replicas through 3D printing procedure. In this work, an overview on modern approaches for automatic and semiautomatic segmentation of medical imagery for 3D surface model generation is provided. The issue of accuracy check of surface models is also addressed, together with the critical aspects of converting digital models into physical replicas through 3D printing techniques. A patient-specific 3D modelling and printing procedure (Figure 1), for surgical planning in case of complex heart diseases was developed. The procedure was applied to two case studies, for which MCT scans of the chest are available. In the article, a detailed description on the implemented patient-specific modelling procedure is provided, along with a general discussion on the potentiality and future developments of personalized 3D modelling and printing for surgical planning and surgeons practice.

scholarly journals Towards an App to Estimate Patient-Specific Perioperative Femur Fracture Risk

2020 ◽  
Vol 10 (18) ◽  
pp. 6409 ◽  
Author(s):  
L. Esposito ◽  
V. Minutolo ◽  
P. Gargiulo ◽  
H. Jonsson ◽  
M. K. Gislason ◽  
...  
Keyword(s):  
Decision Making ◽  
Fracture Risk ◽  
Ad Hoc ◽  
Strength Distribution ◽  
Bone Diseases ◽  
Medical Decision ◽  
Patient Specific ◽  
Decision Making Process ◽  
Geometrical Parameters ◽  
Traffic Light

Total Hip Arthroplasty has been one of the most successful surgical procedure in terms of patient outcomes and satisfaction. However, due to increase in life expectancy and the related incidence of age-dependent bone diseases, a growing number of cases of intra-operative fractures lead to revision surgery with high rates of morbidity and mortality. Surgeons choose the type of the implant, either cemented or cementless prosthesis, on the basis of the age, the quality of the bone and the general medical conditions of the patients. Generally, no quantitative measures are available to assess the intra-operative fracture risk. Consequently, the decision-making process is mainly based on surgical operators’ expertise and qualitative information obtained from imaging. Motivated by this scenario, we here propose a mechanical-supported strategy to assist surgeons in their decisions, by giving intelligible maps of the risk fracture which take into account the interplay between the actual mechanical strength distribution inside the bone tissue and its response to the forces exerted by the implant. In the presented study, we produce charts and patient-specific synthetic “traffic-light” indicators of fracture risk, by making use of ad hoc analytical solutions to predict the stress levels in the bone by means of Computed Tomography-based mechanical and geometrical parameters of the patient. We felt that if implemented in a friendly software or proposed as an app, the strategy could constitute a practical tool to help the medical decision-making process, in particular with respect to the choice of adopting cemented or cementless implant.

A rapid prototyping-based methodology for patient-specific contouring of osteotomy plates

2019 ◽  
Vol 25 (5) ◽  
pp. 888-894
Author(s):  
Behnam Gomari ◽  
Farzam Farahmand ◽  
Hassan Farkhondeh
Keyword(s):  
Rapid Prototyping ◽  
Locking Plate ◽  
Patient Specific ◽  
Osteotomy Site ◽  
Content Type ◽  
Tibial Plate ◽  
Important Challenge ◽  
Surgical Application ◽  
Bone Fragments ◽  
Plate Spring

Purpose An important challenge of the osteotomy procedures, particularly in the case of large and complex corrections, is the fixation of the osteotomy site. The purpose of this study is to propose a practical and cost-effect methodology for the plate adapting problem of osteotomy surgery. Design/methodology/approach A novel patient-specific plate contouring methodology, based on rapid prototyping (RP) and multi-point forming (MPF) techniques, was developed and evaluated. In this methodology, a female mold is fabricated by RP, based on the geometry of the osteotomy site and estimation of the plate spring back. The mold is then used to configure a MPF die, which is then used for press forming of the factory-made locking plate. The applicability of the methodology was assessed in two case studies. Findings The results of implementing the methodology on a femoral and a tibial locking plate indicated very good conformity with the underlying bone, in both the frontal and sagittal planes. The surgical application of the pre-operatively contoured tibial plate facilitated the plate locating and screw inserting procedures, and provided a secure fixation for bone fragments. Practical implications The results are promising and provide a proof of concept for the feasibility and applicability of the proposed methodology in clinical practice, as a complementary to the existing surgical preplanning and patient-specific instrument preparations. Originality/value The advantageous features of RP and the MPF were used to provide a solution for the plate adapting problem of osteotomy surgery.

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