Anterior Skull Base Reconstruction Using Nasoseptal Flap: Cadaveric Feasibility Study

Objectives: There is limited cadaveric data regarding the feasibility of pedicled nasoseptal flap (PNSF) for anterior skull base (ABS) reconstruction. The purpose of this study is to assess the feasibility of PNSF for ASB reconstruction and to describe a method to compensate the shortage of flap length using a cadaveric model. Methods: Using 10 formalin-fixed and 5 fresh adult cadaver specimens, ASB dissection without sphenoidotomy was performed, and sufficiency of the PNSF to cover the ASB was assessed. After sphenoidotomy, the insufficient length to the posterior wall of the frontal sinus, extent of anterior coverage from the limbus of the sphenoid bone (CL) using PNSF was measured. Results: Without sphenoidotomy, mean length of the remaining PNSF after coverage of the posterior wall of the frontal sinus (CPFS) was 0.67 cm (standard deviation [SD] = 0.38 cm); all dissections showed sufficient coverage of ASB using PNSF without sphenoidotomy. After sphenoidotomy, mean insufficiency in the length of PNSF to the posterior wall of the frontal sinus was 2.10 cm (SD = 0.41 cm), CL: 1.86 cm (SD = 0.51 cm). Correlations between CPFS without sphenoidotomy and CL were not positive ( r = 0.165, p = 0.557). Conclusion: The use of PNSF for ASB reconstruction can be associated with cerebrospinal fluid leakage. The length of ASB coverage using PNSF can be increased by remaining the anterior wall of sphenoid sinus as it can support the pedicle of PNSF, so it can raise success rate of ASB reconstruction using PNSF. For large tumors which need a wide sphenoidotomy for tumor resection, additional methods could be needed for ASB reconstruction.