Three-dimensional-printed patient-specific Kirschner-wire guide for percutaneous fixation of undisplaced scaphoid fractures: a cadaveric study

2019 ◽  
Vol 44 (7) ◽  
pp. 692-696 ◽  
Author(s):  
Vincent Salabi ◽  
Guillaume Rigoulot ◽  
Alain Sautet ◽  
Adeline Cambon-Binder
Keyword(s):  
Kirschner Wire ◽  
Three Dimensional ◽  
Cadaveric Study ◽  
Ct Scans ◽  
Patient Specific ◽  
Angular Deviation ◽  
Percutaneous Fixation ◽  
Scaphoid Fractures ◽  
Cadaveric Model ◽  
The Ideal

Undisplaced scaphoid waist fractures can be managed by percutaneous fixation. The purpose of this study is to compare percutaneous fixation using a three-dimensional (3-D)-printed guide with the conventional method in a cadaveric study. Twelve wrists were divided into two groups: standard fluroscopic technique group, and a patient-specific 3-D-printed guide group. In the patient-specific group, using high resolution CT scans, we manufactured a mould-guide including a wire guide sleeve aligned with the planned ideal path, and 3-D printed it. On postoperative CT scans we measured the angular deviation of the screw axis from the ideal axis, and compared the two groups. The angular deviation was significantly lower in the patient-specific guide group. We concluded that a 3-D-printed guide for scaphoid percutaneous fixation allows a more accurate placement of the screw than a fluoroscopy guide in our cadaveric model.

A three-dimensional printed patient-specific scaphoid replacement: a cadaveric study

2018 ◽  
Vol 43 (4) ◽  
pp. 407-412 ◽  
Author(s):  
Philipp Honigmann ◽  
Ralf Schumacher ◽  
Romy Marek ◽  
Franz Büttner ◽  
Florian Thieringer ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Three Dimensional ◽  
Cadaveric Study ◽  
Patient Specific ◽  
Test Results ◽  
Physiological Range

We present our first cadaveric test results of a three-dimensional printed patient-specific scaphoid replacement with tendon suspension, which showed normal motion behaviour and preservation of a stable scapholunate interval during physiological range of motion.

scholarly journals Three-Dimensional Radiographic Evaluation of the Malar Bone Engagement Available for Ideal Zygomatic Implant Placement

2020 ◽  
Vol 3 (3) ◽  
pp. 52 ◽  
Author(s):  
Gerardo Pellegrino ◽  
Francesco Grande ◽  
Agnese Ferri ◽  
Paolo Pisi ◽  
Maria Giovanna Gandolfi ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Ct Scans ◽  
Radiographic Evaluation ◽  
Anatomical Landmarks ◽  
Malar Bone ◽  
Implant Placement ◽  
Zygomatic Implants ◽  
Edentulous Patients ◽  
Zygomatic Implant ◽  
The Ideal

Zygomatic implant rehabilitation is a challenging procedure that requires an accurate prosthetic and implant plan. The aim of this study was to evaluate the malar bone available for three-dimensional zygomatic implant placement on the possible trajectories exhibiting optimal occlusal emergence. After a preliminary analysis on 30 computed tomography (CT) scans of dentate patients to identify the ideal implant emergencies, we used 80 CT scans of edentulous patients to create two sagittal planes representing the possible trajectories of the anterior and posterior zygomatic implants. These planes were rotated clockwise on the ideal emergence points and three different hypothetical implant trajectories per zygoma were drawn for each slice. Then, the engageable malar bone and intra- and extra-sinus paths were measured. It was possible to identify the ideal implant emergences via anatomical landmarks with a high predictability. Significant differences were evident between males and females, between implants featuring anterior and those featuring posterior emergences, and between the different trajectories. The use of internal trajectories provided better bone engagement but required a higher intra-sinus path. A significant association was found between higher intra-sinus paths and lower crestal bone heights.

scholarly journals Optimization of Computed Tomography Angiography Protocols for Follow-Up Type B Aortic Dissection Patients by Using 3D Printed Model

2021 ◽  
Vol 11 (15) ◽  
pp. 6844
Author(s):  
Chia-An Wu ◽  
Andrew Squelch ◽  
Shirley Jansen ◽  
Zhonghua Sun
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Aortic Dissection ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Ct Scans ◽  
Patient Specific ◽  
Type B ◽  
Type B Aortic Dissection ◽  
3D Printed

Thoracic endovascular aortic repair (TEVAR) is a life-saving therapy for type B aortic dissection (TBAD). However, surveillance computed tomography (CT) scans in post-TEVAR patients are associated with high radiation dose, thus resulting in potential risk of radiation-induced malignancy. In this study, we developed a patient-specific three-dimensional (3D) printed phantom with stent grafts in situ, then scanned the phantom with different CT protocols to determine the optimal scanning parameters for post-treatment patients. The CT scans were conducted with different kVp and pitch values (80, 100, 120 kVp and pitch of 1.2, 1.5, 2.0, 2.5), resulting in a total of 12 datasets. Signal-to-noise ratio (SNR) was measured to determine and compare the image quality between different datasets. Results showed no significant differences in SNR between different kVp when the pitch value was 1.2. At low pitch values, a decrease in kVp from 120 to 80 led to a significant effective dose reduction by more than 20%. SNR decreased by 30% when pitch was increased from 1.2 to 2.5 at 80 kVp, and 20% at 120 kVp. In contrast, there was only a 3.9% decrease in SNR when kVp was reduced from 120 to 80 at pitch 1.2, and 15.9% at pitch 2.5. High pitch with 100 kVp can effectively reduce the dose while maintaining image quality.

Scaphoid fracture displacement is not correlated with the fracture angle

2021 ◽  
pp. 175319342110044
Author(s):  
Ophir Aruse ◽  
Igor Immerman ◽  
Omar Badir ◽  
Madi El Haj ◽  
Ido Volk ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Computer Model ◽  
Scaphoid Fracture ◽  
Three Dimensional ◽  
Principal Component ◽  
Ct Scans ◽  
Level Of Evidence ◽  
Fracture Angle ◽  
Fracture Displacement ◽  
Scaphoid Fractures

Classifications of scaphoid fractures associate the angle of the fracture with its stability. To examine this assumption, we measured acute scaphoid fracture angles and inclinations in relation to different scaphoid axes, using fracture displacement as an indicator of instability. We examined the effect of using different axes on the measurements of angles. CT scans of 133 scaphoid fractures were classified according to the location of the fractures. Using a three-dimensional computer model, we computed four scaphoid axes. For each fracture, we then measured the fracture angle and the direction of the fracture inclination in relation to each one of the axes. We found a correlation between displacement and the angles of proximal fractures using one of these axes (the surface principal component analysis axis). No such correlations were found for waist fractures, which were the majority of fractures. There were significant differences between the measurements made with different axes. The findings indicate that the angle of the fracture and the direction of the fracture inclination are minor factors in the displacement of most scaphoid fractures. Level of evidence: III

Use of rotational angiography in congenital cardiac catheterisations to generate three-dimensional-printed models

2021 ◽  
pp. 1-5
Author(s):  
Michael D. Seckeler ◽  
Brian A. Boe ◽  
Brent J. Barber ◽  
Darren P. Berman ◽  
Aimee K. Armstrong
Keyword(s):  
Three Dimensional ◽  
Ct Scans ◽  
Patient Specific ◽  
Rotational Angiography ◽  
Imaging Data ◽  
Three Dimensional Printing ◽  
Three Dimensional Models ◽  
Procedural Planning ◽  
The Cost ◽  
Dimensional Printing

Abstract Background: Three-dimensional printing is increasingly utilised for congenital heart defect procedural planning. CT or MR datasets are typically used for printing, but similar datasets can be obtained from three-dimensional rotational angiography. We sought to assess the feasibility and accuracy of printing three-dimensional models of CHD from rotational angiography datasets. Methods: Retrospective review of CHD catheterisations using rotational angiography was performed, and patient and procedural details were collected. Imaging data from rotational angiography were segmented, cleaned, and printed with polylactic acid on a Dremel® 3D Idea Builder (Dremel, Mount Prospect, IL, USA). Printing time and materials’ costs were captured. CT scans of printed models were compared objectively to the original virtual models. Two independent, non-interventional paediatric cardiologists provided subjective ratings of the quality and accuracy of the printed models. Results: Rotational angiography data from 15 catheterisations on vascular structures were printed. Median print time was 3.83 hours, and material costs were $2.84. The CT scans of the printed models highly matched with the original digital models (root mean square for Hausdorff distance 0.013 ± 0.003 mesh units). Independent reviewers correctly described 80 and 87% of the models (p = 0.334) and reported high quality and accuracy (5 versus 5, p = NS; κ = 0.615). Conclusion: Imaging data from rotational angiography can be converted into accurate three-dimensional-printed models of CHD. The cost of printing the models was negligible, but the print time was prohibitive for real-time use. As the speed of three-dimensional printing technology increases, novel future applications may allow for printing patient-specific devices based on rotational angiography datasets.

Three-Dimensional-Printed Patient-Specific Osteotomy Guides, Repositioning Guides and Titanium Plates for Acute Correction of Antebrachial Limb Deformities in Dogs

2020 ◽  
Author(s):  
Darren R. Carwardine ◽  
Mark J. Gosling ◽  
Neil J. Burton ◽  
Ffion L. O'Malley ◽  
Kevin J. Parsons
Keyword(s):  
Kirschner Wire ◽  
Three Dimensional ◽  
Case Series ◽  
Deformity Correction ◽  
Patient Specific ◽  
Kirschner Wire Fixation ◽  
Limb Deformities ◽  
Acute Correction ◽  
3D Printed

Abstract Objectives The aim of this study was to describe the use of patient-specific three-dimensional (3D)-printed osteotomy guides, repositioning guides and custom-printed titanium plates for acute correction of antebrachial limb deformities in four dogs. Methods Retrospective review of antebrachial limb deformities in small breed chondrodystrophic dogs that were surgically corrected using a closing wedge ostectomy of the radius at a predetermined site using patient-specific osteotomy guides. Reduction was achieved without the need for intraoperative measurements using patient-specific 3D-printed repositioning guides secured and manipulated using temporary Kirschner wire fixation. The ostectomy of the radius was stabilized with a patient-specific 3D-printed titanium plate. Results All limbs were corrected to within 3.5 degrees (standard deviation [SD]: 1 degree) and 7.5 degrees (SD: 3 degrees) of the pre-planned deformity correction in the frontal and sagittal planes, respectively. No complications were encountered. Owners completed a canine orthopaedic index survey at a median postoperative follow-up time of 19 months. Surgery eliminated the main presenting complaint of buckling over of the manus in all cases. Clinical Significance The 3D-printed osteotomy repositioning guides and titanium plates facilitated accurate acute correction of antebrachial deformities in this case series. The methodology described simplifies intraoperative surgical decision-making on limb position with good clinical outcomes seen in a small number of clinical cases.

Criteria and Methods for Reliable Three-Dimensional Image Reconstruction

1974 ◽  
Vol 32 ◽  
pp. 330-331
Author(s):  
R. A. Crowther
Keyword(s):  
Image Reconstruction ◽  
Finite Number ◽  
Density Distribution ◽  
Electron Micrographs ◽  
Mathematical Problem ◽  
Three Dimensional ◽  
Ideal Case ◽  
Dimensional Image ◽  
General Object ◽  
The Ideal

The reconstruction of a three-dimensional image of a specimen from a set of electron micrographs reduces, under certain assumptions about the imaging process in the microscope, to the mathematical problem of reconstructing a density distribution from a set of its plane projections.In the absence of noise we can formulate a purely geometrical criterion, which, for a general object, fixes the resolution attainable from a given finite number of views in terms of the size of the object. For simplicity we take the ideal case of projections collected by a series of m equally spaced tilts about a single axis.

scholarly journals Numerical computation of blood flow for a patient-specific hemodialysis shunt model

2021 ◽  
Author(s):  
Surabhi Rathore ◽  
Tomoki Uda ◽  
Viet Q. H. Huynh ◽  
Hiroshi Suito ◽  
Toshitaka Watanabe ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Arteriovenous Shunt ◽  
Navier Stokes ◽  
Patient Specific ◽  
Stabilized Finite Element ◽  
Computed Tomography Scanning ◽  
Outflow Boundary ◽  
Stage Renal Disease ◽  
End Stage

AbstractHemodialysis procedure is usually advisable for end-stage renal disease patients. This study is aimed at computational investigation of hemodynamical characteristics in three-dimensional arteriovenous shunt for hemodialysis, for which computed tomography scanning and phase-contrast magnetic resonance imaging are used. Several hemodynamical characteristics are presented and discussed depending on the patient-specific morphology and flow conditions including regurgitating flow from the distal artery caused by the construction of the arteriovenous shunt. A simple backflow prevention technique at an outflow boundary is presented, with stabilized finite element approaches for incompressible Navier–Stokes equations.

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