Designing and additive manufacturing of customizable, modular scaffold blocks for large bone defects

Acar, Anıl Ahmet (2020) Designing and additive manufacturing of customizable, modular scaffold blocks for large bone defects. [Thesis]

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Bone has an excellent capacity to regenerate itself after damage, especially for minor defects. However, for large bone defects, external intervention is needed. One of the most suitable external treatments for large bone defects is tissue engineering using a scaffold. However, the transplanted scaffold must conform to the unique morphological features of the patient's bone while providing adequate biomechanical support with the 3D porous inner structure. With additive manufacturing (AM), producing a structure that meets these requirements is possible. But the current customized scaffold design method (reverse engineering technique) is time-consuming, labor-intense and expensive due to the software and machinery used in the process (2D medical image acquisition machine, medical image processing software), and the joint work of technical and surgical staff to finalize the design of the scaffold. Depending on the complexity of the case, the design phase can take months. But in some cases, like high energy injuries, the proper treatment should be held in the fastest way possible. Otherwise, the patient may face severe and irreversible problems like unbearable pain, long hospitalized time, and even limb loss. In this thesis, a method of constructing a best fitting scaffold for the treatment of large bone defects from pre-printed modular blocks is introduced. A femur surface modeling algorithm using morphological features of the femur as input was created. With this algorithm, femur model of a patient is obtained with measuring the necessary measurements from the fewer number of 2D medical images obtained by more common methods such as x-ray images. To create modular blocks, a parametric modelling method was developed. Modules with different topological features can be created by changing the parameters in this algorithm as desired. For path planning for additively manufacturing scaffolds, a novel algorithm has been developed where the created modular blocks are used as input and a continuous path planning is produced. As output from this algorithm, a novel, zig-zag and spiral pattern to manufacture the modules was obtained as instruction for an extrusion-based additive manufacturing process. As the last step, a system was developed that includes assembly and sequence information of the printed modules. This system informs the clinician in the field about how many of which on-demand modules they could use to create a best fitting patient specific scaffold to represent the defect area of the patient. By following the instruction, the clinician puts the proper scaffold blocks on top of each other and implants the assembled scaffold structure on the body. This study represents a promising approach in the creation of a new customized best fitting scaffold with less time, money and effort for healing large bone defects
Item Type: Thesis
Uncontrolled Keywords: Customized design. -- Additive manufacturing. -- Large bone defect. -- Özelleştirilebilir tasarım. -- Eklemeli imalat. -- Büyük kemik kusurları.
Subjects: T Technology > TS Manufactures > TS0155-194 Production management. Operations management
Divisions: Faculty of Engineering and Natural Sciences > Academic programs > Manufacturing Systems Eng.
Faculty of Engineering and Natural Sciences
Depositing User: IC-Cataloging
Date Deposited: 04 Nov 2020 14:19
Last Modified: 26 Apr 2022 10:35

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