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International Journal of Bioprinting Progress in bioprinted ear reconstruction

which govern advanced therapeutic medicinal products, one level IV study demonstrates that this is very much
may provide some guidance [37,38] . an evolving field. However, it is a field that holds much
Despite the progress in regulatory approval for promise, and the emergence of human trials internationally
3D-printed medical devices, such as the FDA-approved attests to this. Notably, phase 1 and 2 human trials are
AXIOM 20 3D printer and iFuse-3D implant, clear currently underway in the United States and are due to be
[45,46]
regulatory pathways for 3D-bioprinted tissues and their completed by February 2028 . This demonstrates that
clinical applications are still needed . this particular innovation has the potential to be adopted
[39]
into clinical practice soon. However, a number of regulatory
4.2. Adjuvant considerations and practical concerns still need to be overcome. There
From a surgical standpoint, this emerging technology is tremendous translational potential, and even if it may
should be examined holistically, including adjuvant not necessarily become a routine component of microtia
techniques and factors that may impact outcomes. reconstruction overnight, auricle bioprinting may pave
the way for 3D printing in other reconstructive efforts in
4.2.1. Additional cover plastic surgery over the next decade.
In some trauma or burns cases, when more skin cover is
necessary and cannot be sourced locally, a radial forearm Acknowledgments
pre-laminated flap may be a good source of additional skin,
with an auricular scaffold implanted in the forearm before None.
the main reconstruction . Alternatively, good outcomes
[2]
are achievable with skin grafts on top of 3D-printed Funding
scaffolds . As with allografts, a temporoparietal fascial None.
[3]
flap may be used with scaffolds to help mitigate soft tissue
complications . However, this carries additional local Conflict of interest
[4]
morbidity and prolongs operating time, so ultimately, a
flap is not needed in the reconstruction at all. None.

4.2.2. Hearing restoration Author contributions
Conductive hearing loss is present in 85% of microtia Conceptualization: Anna Onderková
case ; thus, canalplasty is usually required to obtain a Supervision: Deepak M. Kalaskar
[35]
patent external auditory canal (EAC). The timing of the Visualization: Anna Onderková
canaloplasty is linked to planned auricular reconstruction. Writing – original draft: Anna Onderková
It is typically done after it so an unoperated and Writing – review & editing: Anna Onderková, Deepak M.
unscarred field is preserved for auricle placement, and Kalaskar
the delay avoids the need to center the framework over a
drilled-out canal . Ethics approval and consent to participate
[40]
3D printing is also being developed for EAC Not applicable.
reconstruction , and so far, techniques like using drug-
[41]
releasing implants have been incorporated to prevent Consent for publication
postoperative restenosis . Tympanic membranes are
[42]
also being printed , as are ossicles . However, these Not applicable.
[44]
[43]
efforts appear to be at a more fledgling stage than auricular
reconstruction, probably because of the more complex Availability of data
functional requirements. Many techniques and materials Not applicable.
used for auricular reconstruction may eventually be
transferrable to other reconstructions, such as the EAC References
and vice versa.
1. Humphries S, Joshi A, Webb WR, et al., 2021. Auricular
5. Conclusion and future outlook reconstruction: Where are we now? A critical literature
The auricle is uniquely histologically suitable for 3D review. Eur Arch Oto-Rhino-Laryngol, 279(2): 541–56.
printing, but a plethora of challenges remain. The fact that https://10.1007/s00405-021-06903-5
the majority of the existing evidence in this field is thus 2. Rendón-Medina MA, Hanson-Viana E, Arias-Salazar L,
far only foundational and that this review identified only et al., 2022, Auricular total reconstruction with radial

Volume 9 Issue 6 (2023) 304 https://doi.org/10.36922/ijb.0898