L1 vertebral body replacement using 3D-printed polylactic acid bioimplants - in vitro cellular evaluation, in vivo rat model assessment, and histological analysis of implant osseointegration

Sep 30, 2026

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L1 vertebral body replacement is addressed through a pilot study evaluating a novel porous 3D-printed polylactic acid (PLA) implant intended for total vertebral body substitution. The work assesses design and 3D printing, then performs in vitro analyses of biocompatibility and cell growth using cytotoxicity, direct viability, and confocal microscopy-based cytochemical methods. In vivo efficacy is tested in 35 Wistar rats with sequential histology at 2, 4, and 6 months, quantified by a pixel-based algorithm.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages38

Reading Time1 h 36 min

AccessFree to download

Background

Methods

In vitro evaluation

In vivo rat model and histology

Results

Conclusions

L1 vertebral body replacement using 3D-printed polylactic acid bioimplants: in vitro cellular evaluation, in vivo rat model assessment, and histological analysis of implant osseointegration Diogo Lino Moura1,2,3^, Diogo Casal4,5^, Rodrigo Reis4, Luís Gonçalves4, Sara Alves4,6, Dora Pinto6, Manuela Novo7, Guilherme Fontinha8, Rui Almeida8^, Pedro Gameiro Santos9^, João B. Lago10, Gabriela Rodrigues9^, Maria Helena Casimiro11^, Luís M. Ferreira11,12^, João Paulo Leal12,13^, Pedro M. P. Santos11,12^, Diogo Pais4^, José Casanova2,14^, António Bernardes1,15^ 1Anatomy Institute, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; 2University Orthopedic Clinic, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; 3Orthopedics Department-Spine Unit, Coimbra University Hospital, Coimbra, Portugal; 4Anatomy Department, Nova Medical School, Lisbon, Portugal; 5Plastic and Reconstructive Surgery Department and Burn Unit, Central Lisbon Hospital Centre, Lisbon, Portugal; 6Pathology Department, Central Lisbon Hospital Centre, Lisbon, Portugal; 7Pathology Department, Professor Doutor Fernando Fonseca Hospital, Lisbon, Portugal; 8Pathology Department, Coimbra University Hospital, Coimbra, Portugal; 9Centre for Ecology, Evolution and Environmental Changes (CE3C) & CHANGE-Global Change and Sustainability Institute, Department of Animal Biology, Faculty of Sciences, University of Lisbon, Lisbon, Portugal; 10Department of Animal Biology, Faculty of Sciences, University of Lisbon, Lisbon, Portugal; 11Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Bobadela, Portugal; 12Departamento de Engenhariae Ciências Nucleares (DECN), Instituto Superior Técnico, Universidade de Lisboa, Bobadela, Portugal; 13Centro de Química Estrutural (CQE), Institute of Molecular Sciences (IMS), Instituto Superior Técnico, Universidade de Lisboa, Bobadela, Portugal; 14Orthopedics Department, Coimbra University Hospital, Coimbra, Portugal; 15General Surgery Department, Coimbra University Hospital, Coimbra, Portugal Contributions: (I) Conception and design: All authors; (II) Administrative support: All authors; (III) Provision of study materials or patients: All authors; (IV) Collection and assembly of data: All authors; (V) Data analysis and interpretation: All authors; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. Correspondence to: Diogo Lino Moura, MD. Anatomy Institute, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000- 548 Coimbra, Portugal; University Orthopedic Clinic, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal; Orthopedics Department-Spine Unit, Coimbra University Hospital, Coimbra, [Portugal. Email: dflcoluna@gmail.com](Portugal. Email: dflcoluna@gmail.com). Background: The vertebral body plays a crucial role in supporting compressive loads and maintaining spinal biomechanics. An ideal biomaterial for total vertebral body replacement should combine biological and mechanical properties, yet no current material fulfills all criteria. This pilot study explores the use of a novel three-dimensional (3D)-printed porous polylactic acid (PLA) implant for total L1 vertebral body replacement. Methods: This study had four stages: first, design, optimization, and 3D printing of the PLA device; second, in vitro evaluation of biocompatibility and cell growth using indirect cytotoxicity assay, direct cell viability assay, and cytochemical analysis via confocal microscopy; third, in vivo testing in 35 Wistar rats that underwent anterior retroperitoneal abdominal access for total L1 replacement with the PLA device; and finally, sequential histological analysis to assess osseointegration at 2, 4, and 6 months post-implantation. A pixel-based algorithm quantified proportions of PLA material, inflammatory and granulation tissue, fibroblastic and cartilaginous tis

FAQs

What PLA implant is evaluated for total L1 vertebral body replacement?

The study evaluates a porous, 3D-printed polylactic acid (PLA) implant designed for total L1 vertebral body replacement and produced through device design, optimization, and 3D printing.

How were the implant’s cellular and biocompatibility effects tested in vitro?

In vitro testing used indirect cytotoxicity assay, direct cell viability assay, and cytochemical analysis via confocal microscopy to assess biocompatibility and cell growth.

What did the in vivo rat model and histological analysis show over time?

In 35 Wistar rats, histology at 2, 4, and 6 months quantified osseointegration, showing decreasing PLA presence, inflammatory response trends, increasing woven bone and fibrocartilaginous tissue, and predominant mature trabecular bone at 6 months with continuous bone bridging at the interface in most rats.

Sep 30, 2026

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