A comparative study of three-dimensional airway changes after fibula flap reconstruction for benign and malignant tumours in the anterior mandible

Three-dimensional assessment of upper airway changes associated with mandibular positional deviations following fibula free flap reconstruction

OBJECTIVES

Fibula free flaps (FFF) are the standard approach to mandibular reconstruction after partial resection, with the goal of restoring aesthetics and masticatory function. The graft position affects both and must be carefully selected. Correlations between sagittal positioning and upper airway anatomy are known from orthognathic surgery. This study aims to evaluate changes in mandibular position and upper airway anatomy after reconstructive surgery with FFF and corresponding correlations.

MATERIALS AND METHODS

Mandibular position after reconstruction was evaluated using three-dimensional datasets of pre- and postoperative computed tomography scans of patients treated between 2020 and 2022. Three-dimensional measurements were performed on both condyles and the symphyseal region. Changes in upper airway volume and minimum cross-sectional area (minCSA) were analysed. Intra-rater reliability was assessed. Correlations between changes in upper airway anatomy and sagittal mandibular position were tested.

RESULTS

The analysis included 35 patients. Intra-rater reliability was good to excellent. Condylar deviations and rotations were mostly rated as small. Changes in symphyseal position were considerably greater. Median airway volume decreased in the oropharynx and hypopharynx. Posterior deviation of the symphysis was associated with a decreasing minCSA in the hypopharynx and vice versa.

CONCLUSIONS

The overall accuracy of mandibular reconstructions with FFF is high, but there is room for optimization. The focus of research should be extended from masticatory to respiratory rehabilitation.

CLINICAL RELEVANCE

Effects on respiratory function should be considered prior to graft positioning. The clinical relevance of upper airway changes within the complex rehabilitation of reconstructive surgery patients needs to be further investigated.

Influence of microvascular mandibular bony reconstruction on the posterior airway space: A retrospective cohort study

INTRODUCTION

The posterior airway space (PAS) is a common site of passive obstructions with high morbidity. Surgical changes to the craniomandibular system may affect the PAS. Data regarding the effects of mandibular reconstruction using vascularized bone flaps on PAS are insufficient. This retrospective cohort study aimed to investigate changes in PAS after mandibular reconstruction.

MATERIALS AND METHODS

Pre- and post-reconstructive computed tomography scans of 40 patients undergoing segmental mandibulectomy and mandibular reconstruction with deep circumflex iliac artery or fibula flaps were analyzed. Absolute differences in PAS geometry and relative trends of PAS volume changes were compared within the study population and between subgroups formed according to the extent of resection, timing and type of reconstruction, and presence of pre-reconstructive radiotherapy.

RESULTS

Irradiated patients were characterized by an increase in PAS volume after reconstruction. Absolute differences in total PAS volume after reconstruction were significantly different (p = 0.024) compared to non-irradiated patients. Reconstruction of central mandible segments resulted in decrease of the cross-sectional PAS areas. Absolute differences in middle cross-sectional PAS area after reconstruction were significantly different (p = 0.039) compared to non-central reconstructions. Patients who received radiotherapy were less likely to show a total PAS volume reduction after reconstruction (OR: 0.147; p = 0.007), with values adjusted for gender, age, body mass index, timing and type of reconstruction, and transplant length.

CONCLUSIONS

Mandibular reconstruction causes changes in PAS geometry. Specifically, reconstructions of central mandibular segments can lead to a reduction in the cross-sectional areas of PAS, and mandibular reconstructions in irradiated sites may cause an increase in PAS volume.