Vascularized anterolateral thigh free flap for salvage reconstruction of complex anterior skull base and nasion defects after failed conventional reconstruction— how I do it

BACKGROUND: Sinonasal inverted papilloma (SNIP) is histologically benign but locally aggressive, with high recurrence rates and a relevant risk of malignant transformation. Tumor involvement of the nasal root and overlying skin may result in a full-thickness craniofacial defect with direct intracranial-external communication. Reconstruction is particularly challenging after failure of conventional skull base techniques (e.g., titanium mesh and pericranial flaps), which may lead to pneumocephalus, cerebrospinal fluid (CSF) leakage, and infection. OBJECTIVE: To describe a multidisciplinary staged salvage strategy combining bifrontal craniotomy with a vascularized anterolateral thigh (ALT) free flap for definitive reconstruction of complex anterior skull base and nasion defects after failed conventional reconstruction. METHODS: We report a recurrent SNIP case with failed initial skull base reconstruction. After infection control and resolution of pneumocephalus, an ALT free flap was used. The pedicle was routed transcranially through an enlarged skull base defect to temporal recipient vessels, enabling three-layer reconstruction from dura to skin and restoration of nasal dorsum contour. RESULTS: Definitive reconstruction was completed in 7 h. The flap survived without vascular compromise. During the postoperative course and early follow-up, no CSF leak, infection, or recurrent pneumocephalus was observed. Stable intracranial-extracranial separation and satisfactory functional/aesthetic outcomes were achieved. CONCLUSION: Bifrontal re-exploration followed by staged ALT free-flap reconstruction represents a viable salvage option for complex anterior skull base defects after failed primary repair. In our experience, transcranial pedicle routing and a three-layer reconstruction approach can facilitate effective intracranial-extracranial separation.