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J Reconstr Microsurg
DOI: 10.1055/a-2671-9586
Original Article

Evaluating Dynamic Smile Outcomes of Free Gracilis Muscle Transfer in Pediatric Facial Palsy Using Image-Based Analysis

Melanie Bakovic
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
2   The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, United States
,
Asli Pekcan
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
3   Division of Plastic and Reconstructive Surgery, Keck School of Medicine, Los Angeles, California, United States
,
Raina Patel
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
4   Nova Southeastern University Dr. Kiran C. Patel College of Allopathic Medicine, Fort Lauderdale, Florida, United States
,
Valeria Mejia
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
3   Division of Plastic and Reconstructive Surgery, Keck School of Medicine, Los Angeles, California, United States
,
Sally Danto
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
,
Maya Lazar
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
,
William P. Magee III
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
,
Jessica Lee
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
,
Mark A. Urata
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
3   Division of Plastic and Reconstructive Surgery, Keck School of Medicine, Los Angeles, California, United States
5   Division of Oral and Maxillofacial Surgery, Keck School of Medicine, Los Angeles, California, United States
6   Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, United States
,
Jeffrey Hammoudeh
1   Division of Plastic and Maxillofacial Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
3   Division of Plastic and Reconstructive Surgery, Keck School of Medicine, Los Angeles, California, United States
5   Division of Oral and Maxillofacial Surgery, Keck School of Medicine, Los Angeles, California, United States
6   Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, United States
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Abstract

Background

Facial nerve palsy in children leads to significant functional impairment and facial asymmetry. While free gracilis muscle transfer (FGMT) is a cornerstone technique for smile reanimation in both pediatric and adult patients, its evaluation has mainly focused on the single metric of commissure excursion. This study seeks to evaluate the effectiveness of FGMT in restoring dynamic smiles in pediatric patients with facial palsy using image analysis.

Methods

A retrospective review was conducted in children who underwent FGMT for facial palsy at a major children's hospital between 2007 and 2020. Data collection included pre- and postoperative chart reviews and image analysis. Anthropometric measurements were obtained using a machine learning-based smile analysis software. Primary outcomes included commissure excursion, commissure angle, dental show, and smile symmetry. Statistical analysis was performed using the Wilcoxon signed-rank test.

Results

A total of 31 patients with an average age of 10 years underwent FGMT for smile reanimation during the study period. The most common diagnosis was Moebius syndrome (48%). Donor nerves for gracilis neurotization included 18 ipsilateral trigeminal nerves (58.1%) and 12 contralateral facial nerves via cross-face sural nerve grafts (38.7%). Overall, 84% of patients demonstrated active gracilis contraction within a mean of 2.5 years postoperative follow-up. Commissure excursion increased by 9.7 mm at 1 year (p < 0.05), and symmetry significantly improved for commissure height, commissure excursion, upper lip height, and smile angle. There were no significant improvements in dental show, commissure angle, symmetry of dental show, and lower lip height. Furthermore, only 16% of patients demonstrated clinically symmetric smiles within the follow-up period.

Conclusion

While FGMT effectively restores commissure excursion in pediatric patients with facial palsy, achieving multidimensional smile reanimation remains a challenge. New techniques in multi-vector free tissue transfer may help optimize FGMT outcomes in pediatric patients.

Keywords

craniofacial - reanimation - free flap

Ethical Approval

The study was conducted in accordance with the Declaration of Helsinki and received ethical approval from the Children's Hospital Los Angeles IRB (approval #CHLA-24–00011) on January 19, 2024.


Data Availability Statement

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.


Supplementary Material



Publication History

Received: 24 March 2025

Accepted: 27 July 2025

Accepted Manuscript online:
30 July 2025

Article published online:
01 September 2025

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