Innovative approaches to designing and manufacturing a prosthetic thumb

Abstract

Case description: Conventional methods for producing custom prosthetic fingers are time-consuming, can be uncomfortable for the patient, and require a skilled prosthetist. The subject was a 40-year-old male with congenital absence of the thumb and related metacarpal bone on the right non-dominant hand, anomaly of the lengths of individual upper limb segments, and contracture of the elbow joint. This hand presentation made it impossible for him to perform thumb opposition, which is a very important function for common daily activities. Objective: The goal was to design an individual passive thumb prosthesis using free open-source software, 3D scanning technology, and additive manufacturing methods (i.e., fused filament fabrication). Study design: Case report. Treatment: Artificial thumb prostheses with two types of bases and fastening interfaces were designed and manufactured. One combination was chosen as the best alternative. Outcomes: The shape, positioning, firmness, and fastening of the prosthesis were compliant enough for the patient to be able to hold objects with his healthy fingers and artificial thumb. This innovative approach to fabrication of a custom thumb prosthesis provided considerable advantages in terms of custom sizing, manufacturing time, rapid production, iteration, comfort, and costs when compared to conventional methods of manufacturing a hand prosthesis. Conclusion: The methodology of designing and manufacturing a prosthetic thumb using 3D scanning and additive manufacturing technologies have been demonstrated to be adequate from a practical point of view. These technologies show potential for use in the practice of prosthetics.

The use of 3d printing technology in the development of a prosthetic thumb

“…W przypadku pracy Štefanovič i wsp. [1] zdecydowano się na skan zarówno ręki zdrowej, jak i chorej, z wrodzonym brakiem kciuka i kości śródręcza. Otrzymany skan posłużył jako model służący do wstępnego dopasowania protezy.…”

“…Ważną kwestią dla pacjenta były nie tylko kształt i pozycja protezy, ale także odpowiednia sztywność oraz możliwość samodzielnego zakładania. Spełnienie wszystkich tych wymogów umożliwiło pacjentowi wykonanie chwytu szczypcowego, trójpunktowego jak i siłowego [1].…”

“…[3] W zależności od materiału można regulować jego cechy, takie jak między innymi sztywność, odporność na promieniowanie UV czy temperaturę. Materiały używane w druku protez to poliaktyd (PLA), ABS oraz TPU90 [1,[3][4][5][6]. Druk 3D w technologii FDM umożliwia stworzenie zarówno obiektów pustych w środku, jak i wypełnionych tylko częściowodzięki temu łatwo możemy modyfikować masę danego modelu oraz jego wytrzymałość.…”

Evaluation of Topological Modification on Gear Wheel Bodies

“…The density of the materials in the grid is then used to create a design space. This method can represent a variety of topologies and is used to discover the best design for a specific goal (typically compliance minimization) [24][25][26]. Topology optimization is a method for getting beyond the restrictions of parametric generative design, such as when geometrical parameterizations aren't enough to cover a wide design space.…”

Sensor Architectures and Technologies for Upper Limb 3D Surface Reconstruction: A Review

“…The 3D scanning procedure showed that the construction of the jig allowed it to efficiently capture the upper-limb anatomy from dorsal and palmar sides and generate a whole upper-limb 3D scan geometry ( Figure 9 c). The same device was also used in [ 79 ] to scan the upper limb anatomy of a patient with congenital absence of the thumb to design a customized thumb prosthesis.…”