Long-Term Outcomes of Secondary Nasal Tip Plasty After Degradation of a Polycaprolactone (PCL) Mesh

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.

Analysis of the Effectiveness of Anterior Septal Reconstruction in Asians

Background: Although anterior septal reconstruction (ASR) is effective, it is less commonly employed in Asian patients compared with the septal extension graft technique, even in cases of severe antero-caudal septal deviation. Objective: To compare airflow and patient perceptions after ASR in patients of Korean descent with caudal septal deviations and external nasal deformities, we considered the potential tendency of their septal cartilage to be smaller and less robust compared with that of Caucasians. The measurements were conducted using acoustic rhinometry and patient-reported outcomes. Methods: We analyzed 103 patients using preoperative and 3-month postoperative assessments: Korean version of the Standardized Cosmesis and Health Nasal Outcomes Survey (K-SCHNOS), obstructive (SCHNOS-O), and cosmetic (SCHNOS-C) scores, and minimal cross-sectional area (MCA) measured by acoustic rhinometry. Results: Among 103 patients (mean age 33.36 years, median age 32 years, age range 17-70 years, 77 men [75%], and 26 women [25%]), the average follow-up period for the patients was 264.6 days (median 202 days and range 13-1540 days), SCHNOS-O scores improved significantly from 64.02 ± 4.89 to 19.31 ± 4.45 after ASR (p < 0.001), as did SCHNOS-C scores, improving from 60.61 ± 7.71 to 14.25 ± 4.66 (p < 0.001). MCA increased from 0.30 ± 0.16 cm2 to 0.56 ± 0.38 cm2 (p < 0.001). Conclusions: As measured by MCA and SCHNOS scores at 3 months postoperatively, ASR proves valuable for correcting antero-caudal septal deviations and nasal deformities in Asians, despite the tendency of their septal cartilage to be smaller and less strong compared with that of Caucasians.