Pilot study for the validation of the design and development process of customized upper limb prostheses and orthoses using 3D printing.

Autori

Azzurra Speroni [Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy]

Fabrizio Taffoni [Advanced Robotics and Human-Centered Technologies Research Unit – Creo lab, Università Campus Bio-Medico di Roma, Rome, Italy]

Maurizio Petrarca [Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy]

Francesca Cordella [Advanced Robotics and Human-Centered Technologies Research Unit – Creo lab, Università Campus Bio-Medico di Roma, Rome, Italy]

Claudia Bigas [Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy]

Gessica Della Bella [Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy]

Loredana Zollo [Advanced Robotics and Human-Centered Technologies Research Unit – Creo lab, Università Campus Bio-Medico di Roma, Rome, Italy]]

Background and aims

The human hand is crucial for performing daily activities, and its loss or functional impairment can significantly reduce an individual’s autonomy. Amputation may lead to a disability rating of up to 54% [1], while trauma- or congenital-related dysfunctions of individual fingers can result in variable functional limitations. Robotic prostheses and orthoses represent a promising approach to compensate for these deficits, despite most existing devices lack patient-centered design. Customization and affordability remain key challenges, especially in pediatric applications. The 3D-AID study addresses these issues by focusing on the customization of the mechanical structure of hand prostheses and orthoses, with the goal of improving wearability and reducing production costs.

Methods

The 3D-AID pilot study aims to define a procedure for acquiring data useful for identifying inter-joint coupling patterns and anatomical shapes for customized mechanical design. These data are also used to evaluate the quality and effectiveness of the resulting design. Two groups will be recruited: healthy pediatric volunteers (Group Vp), for kinematic data acquisition and 3D limb scanning to test motion reconstruction protocols and CAD parameterization; and pediatric patients with hand agenesis or transradial amputation (Group Ap), divided into three age groups (3–5, 6–10, and 11–14 years). In the first phase, anthropometric and unassisted flexion-extension kinematic data will be collected through digital scanning and stereophotogrammetry (BTS). In the second phase, these data will be used to design personalized virtual prototypes, which will be fabricated using Selective Laser Sintering (SLS) technology. Each device will undergo technical and functional evaluation to validate and optimize the proposed methodology. [2,3]

Results

The study collected pediatric hand anthropometric data and flexion-extension trajectories [4], using conventional methods and the EINSCAN HX 3D scanner, generating digital models through EXScanHX software for CAD integration. Flexion-extension trajectories were recorded with an 8-camera stereophotogrammetric system (SMART-DX, BTS) using reflective markers. Key parameters included finger joint angles, range of motion (ROM), and inter-joint angular couplings. [5] These initial data enabled the establishment of reliable protocols and baseline metrics for the customized design of pediatric prostheses.

Conclusion

Preliminary results of the 3D-AID study confirm the feasibility of combining 3D scanning, biomechanical analysis, and additive manufacturing to generate quantitative data for device customization, including pediatric applications. The proposed setup enables a data-driven manufacturing workflow for patient-specific designs. These findings support future clinical validation and highlight the potential to enhance personalization, functionality, and accessibility of upper limb assistive technologies in children.

REFERENCES

[1] Ziegler-Graham K, MacKenzie EJ, Ephraim PL, Travison TG, Brookmeyer R. Archives of Physical Medicine and Rehabilitation 2008;89(3):422-429.

[2] Cordella F, Zollo L, Salerno A, Accoto D, Guglielmelli E, Siciliano B. Int J Adv Robot Syst 2014;11(3):37

[3] Cordella F, Ciancio AL, Sacchetti R, Davalli A, Cutti AG, Guglielmelli E, Zollo L. Front Neurosci 2016;10:209.

[4] Nini L, Ceccarelli A, Tagliamonte NL, Zollo L, Taffoni F. Parametric 3D modeling of a customized prosthetic hand finger for additive manufacturing. In: 2024 10th IEEE RAS/EMBS International Conference for Biomedical Robotics and Biomechatronics (BioRob). IEEE; 2024:1328–1333.

[5] Lapresa M, Ceccarelli A, Taffoni F, Tagliamonte NL, Zollo L, Cordella F. Analysis of hand intra-finger couplings during flexion movements in the free space. IEEE Access 2023; 11:90084–90093.