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

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. 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. 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. 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.