SA3 - Custom Endoprosthesis Reconstruction Improves Facial Symmetry Following Microsurgical Jaw Reconstruction

Abstract:

Background: Surgical resection of pediatric mandibular tumors may result in significant facial disfigurement. While custom endoprosthesis (CE) and non-custom reconstruction (NCR) have been successfully used for microsurgical mandibular reconstruction, the comparative impact on facial symmetry between these techniques remains poorly characterized. This study analyzes facial anthropometrics to compare improvement in post-resection disfigurement among children undergoing CE and NCR following hemimandibulectomy.

Methods: A retrospective review was conducted of children who underwent mandibular reconstruction at a major children’s hospital between 2009 and 2022. Cohorts included patients receiving CE and NCR. Anthropometric measurements from frontal images taken one year postoperatively included gonion-to-menton (Go-Me), gonion-to-midline (Go-Mid), stomion-to-cheilion (Sto-Ch), intercanthal line (ICL) to gonion (ICL-Go) and ICL to cheilion (ICL-Ch) (Figure 1). Symmetry ratios between the surgical and non-operative sides were calculated, with 1.0 signifying ideal symmetry. The percentage of absolute deviation from ideal symmetry was calculated, with lower values indicating favorable outcomes. Statistical analysis was performed using Fisher's exact and Mann-Whitney U tests.

Results: A total of 25 patients undergoing mandibular reconstruction met inclusion criteria. Thirteen patients received CE and 12 underwent NCR. Of the resected tumors, 84% were benign and 16% were malignant. None of the patients received preoperative radiation therapy. Reconstructive methods included free tissue transfer (CE: 69.2% vs NCR: 16.7%), bone grafting (23.1% vs 66.7%), and local flaps (7.7% vs 16.7%) (P = .03). Overall flap survival was 100%. Hardware failure occurred in 7.7% of CE and 50.0% of NCR patients (P = .03). Postoperatively, the CE cohort demonstrated decreased deviation from ideal symmetry compared to the NCR cohort in four anthropometric metrics (Go-Mid: 11.3% vs 14.2% , P = .42; Sto-Ch: 8.6% vs 11.3%, P = .39; ICL-Go: 4.6% vs 7.0%, P = .29; Go-Me: 7.1% vs 9.9%, P = .41). The CE cohort exhibited greater deviation from symmetry in only one metric (ICL-Ch: 2.7% vs 1.3%, P = .12).

Conclusion: Overall, reconstruction with CE demonstrated a trend towards improved facial symmetry compared to NCR, as evidenced by reduced deviation from ideal symmetry in most anthropometric measurements. These findings may inform clinical decision-making and set more accurate preoperative expectations for pediatric mandibular reconstruction. Further studies with a larger patient population are necessary to more precisely determine the significance of differences in postoperative facial symmetry between CE and NCR in microsurgical mandibular reconstruction.
Anthropometric Landmarks for Assessing Facial Symmetry