Analytical evaluation of complex anterior approaches to the cranial base: an anatomic study

OBJECTIVE: The purpose of the present study was to evaluate the anatomic areas of the cranial base exposed by different complex anterior approaches. METHODS: Using 20 embalmed cadaveric heads, we executed five different anterior approaches, i.e., Le Fort 1 approach with splitting or down-fracturing of the hard palate, extended maxillectomy, median mandibulotomy with glossotomy, and mandibular swing transcervical approach. Each approach was performed a minimum of three times. The areas of the intra- and extracranial cranial base exposed by each approach were analytically examined by using a numerical grading system to assess the exposure of major anatomic and neurovascular structures. RESULTS: Good exposure of the midline compartment of the cranial base was provided by the median mandibulotomy with glossotomy and by the Le Fort 1 approach with splitting of the hard palate, whereas the mandibular swing transcervical and extended maxillectomy approaches provided good exposure of the lateral compartment of the cranial base. CONCLUSION: Use of the numerical grading system allowed quantification of the exposure afforded by each approach, with respect to the different compartments (midline and lateral) of the intra- and extracranial cranial base, highlighting the differences among the approaches examined.