Tunneled Transfacial Free Tissue Transfer in Ventral Skull Base Reconstruction

Background Ventral skull base osteoradionecrosis is a defined complication of external beam radiotherapy in the setting of sinonasal malignancy. Potential morbidities include infection, meningitis, carotid artery injury, and death. Adequate reconstruction is necessary to avoid these morbidities and to restore velopharyngeal sufficiency, functional swallow, and voice. Despite available local and regional vascularized tissue options, reconstruction remains challenging due to both difficult surgical access and the bulk necessary to optimize outcomes. We present two cases of skull base osteoradionecrosis managed using free tissue transfer reconstruction inset via a novel transfacial approach.

Case Series Patient 1 is a 51-year-old woman with sinonasal squamous cell carcinoma treated with chemoradiotherapy in 2007, followed by surgical salvage of recurrent disease in 2010. She developed refractory chronic rhinosinusitis and ventral skull base osteomyelitis inadequately controlled by culture-directed antibiotic therapy. Initial debridement and reconstruction utilizing a nasoseptal flap was attempted in 2015, followed 3 months later by further debridement and attempted reconstruction using a temporoparietal flap. She unfortunately developed persistent osteoradionecrosis complicated by carotid canal erosion. As such, a radial forearm free tissue transfer reconstruction was performed the following year, pedicled on the angular artery and inset using a transfacial approach. Patient 2 is a 34-year-old woman with a history of remote nasopharyngeal carcinoma treated with proton beam therapy and chemotherapy. She presented with chronic rhinosinusitis, velopharyngeal incompetence, persistent rhinorrhea, anosmia, headaches, and worsening diplopia. Imaging followed by endoscopic biopsy confirmed osteoradionecrosis of the skull base, with clival erosion and carotid vulnerability. Reconstruction was performed using a transfacial approach for inset of an anterolateral thigh flap pedicled on the angular artery. Both patients are doing well with functional voices and tolerating oral diets.

Discussion The introduction of vascularized tissue options in ventral skull base reconstruction has largely revolutionized endoscopic endonasal surgery. However, defects resulting from osteoradionecrosis remain a significant challenge to the reconstructive surgeon, in part due to the large bulk required for safe and functional reconstruction, as well as the difficulty of surgical access to introduce the flap. The decision for optimal reconstruction is individualized and based on features both of the recipient bed such as defect size and involved subsites, and of the donor site such as tissue availability and necessary tissue bulk. Additional considerations include the status of active infection as well as the degree of functional deficit. We present two patients successfully managed using free tissue flaps inset via novel transfacial approach. Discussion includes intraoperative photos and details of creating a transfacial corridor, identifying acceptable recipient vessels, and appropriate flap harvest. Considerations of tissue bulk on functional outcome are also discussed.

Conclusion Free tissue transfer in ventral skull base reconstruction can be successfully performed via transfacial approach, thus allowing the benefits of large-volume vascularized tissue while avoiding open craniotomy.