Evaluating the Mechanical Strength of 3-Dimensionally Printed Implants in Septorhinoplasty through Finite Element Analysis.

[BACKGROUND] Autologous nasoseptal cartilage grafts are used to correct nasal asymmetry and deviation in rhinoplasty, but patients who have undergone multiple operations may have limited autologous cartilage tissue available. L-strut implants created on a 3-dimensional (3D) printer may address these challenges in the future, but their mechanical strength is understudied. Silk fibroin-gelatin (SFG), polycaprolactone (PCL), and polylactide (PLA) are bioinks known for their strength. The authors present finite element analysis (FEA) models comparing the mechanical strength of 3D-printed SFG, PCL, and PLA implants with nasoseptal cartilage grafts when autologous or allografts are not available.

[METHODS] FEA models compared the stress and deformation responses of 3D-printed solid and scaffold implant replacements to cartilage. To simulate a daily force from overlying soft tissue, a unidirectional load was applied at the "keystone" region given its structural role and compared with native cartilaginous properties.

[RESULTS] The 3D-printed solid SFG, PCL, and PLA and scaffold PCL and PLA models demonstrated lower deformations compared with cartilage. Solid SFG balanced strength and flexibility. The maximum stress was below all materials' yield stresses, suggesting that their deformations are unlikely permanent under a daily load.

[CONCLUSIONS] The authors' FEA models suggest that 3D-printed L-strut implants carry promising mechanical strength. Solid SFG results mimicked cartilage's mechanical behavior. Thus, scaffold SFG merits further geometric optimization for potential use for cartilage substitution. The 3D-printed septal cartilage replacement implants can potentially enhance surgical management of patients who lack available donor cartilage in select settings.

[CLINICAL RELEVANCE STATEMENT] Computational simulations can evaluate the strength of 3D-printed implants and their potential to replace septal cartilage in septorhinoplasty.

[CLINICAL QUESTION/LEVEL OF EVIDENCE] Therapeutic, V.