Advanced Trans-Tibial Socket Fabrication Using Selective Laser Sintering

Abstract

There have been a variety of efforts demonstrating the use of solid freeform fabrication (SFF) for prosthetic socket fabrication though there has been little effort in leveraging the strengths of the technology. SFF encompasses a class of technologies that can create three dimensional objects directly from a geometric database without specific tooling or human intervention. A real strength of SFF is that cost of fabrication is related to the volume of the part, not the part's complexity. For prosthetic socket fabrication this means that a sophisticated socket can be fabricated at essentially the same cost as a simple socket. Adding new features to a socket design becomes a function of software. The work at The University of Texas Health Science Center at San Antonio (UTHSCSA) and University of Texas at Austin (UTA) has concentrated on developing advanced sockets that incorporate structural features to increase comfort as well as built in fixtures to accommodate industry standard hardware. Selective laser sintering (SLS) was chosen as the SFF technology to use for socket fabrication as it was capable of fabricating sockets using materials appropriate for prosthetics. This paper details the development of SLS prosthetic socket fabrication techniques at UTHSCSA/UTA over a six-year period.

Gait assessment during the initial fitting of customized selective laser sintering ankle foot orthoses in subjects with drop foot

“…In literature, there is evidence to support the use of additive manufacturing for producing orthotic or prosthetic devices. [13][14][15][16][17][18][19] However, issues related to material properties and manufacturing costs still need to be investigated before additive technologies could be considered ready for clinical use. Furthermore, it is not clear to the authors how much evidence is necessary before one can consider these manufacturing technologies 'ready for commercial' use.…”

“…12 Additive fabrication (selective laser sintering (SLS), in particular) has been recently proposed as a feasible engineering method for manufacturing of customized prosthetic feet, prosthetic sockets, customized foot orthoses and customized ankle-foot orthoses. [13][14][15][16] This technique allowed developing different manufacturing frameworks to replicate the shape and functional characteristics of existing carbonfibre AFO or to customize shape and functional AFO characteristics under a certain degree of automation. [17][18] Although the feasibility of the SLS manufacturing techniques for prosthetics and orthotics was demonstrated, studies on the safety, comfort and effectiveness of SLS orthotics are only nowadays being considered.…”

Assessment technique for computer-aided manufactured sockets

“…In prosthetics, some patients might require a special, more accurate socket shape while other patients might do fine with the normal quality shape. Presumably, the cost of fabricating a very accurately shaped socket is higher, particularly if the latest technology is used, i.e., additive fabrication techniques [12][13][14][15][16]. One possible means for managing these differences in patient adaptability is to distinguish the minimally adaptable patient by a special rating, for example a rating termed "P-1."…”

“…Direct socket fabrication approaches have been pursued in research investigations and potentially have less error than current CAM techniques [12][13][14][15][16]18]. While moving to one of these technologies can potentially overcome shape fabrication error, these technologies are not yet commercially available for prosthetics.…”

Partial Foot Amputation, Finite Element Analysis of Foot and Manufacturing of Prosthtic Sockets: A Review

“…Examples of AM prosthetic sockets, made by (a) Hertbert et al [24] (b) Roger et al [22] (c) Hsu et al [25] (d) Sengeh et al [26] …”