Surgical Approaches to the Suprasellar Infrachiasmatic Region: Comparison among Pterional, Subfrontal, and Endoscopic Endonasal Approaches

Introduction: The suprasellar infrachiasmatic region (SSICR) can be reached through many different surgical corridors. The goal of this study is to compare two microsurgical (pterional and subfrontal) approaches and the endoscopic endonasal route to access the SSICR.

Methods: Five specimens were prepared for endoscopic and microsurgical dissection at the Surgical Neuroanatomy Laboratory of the University of Pittsburgh Medical Center. The degree of exposure of the SSICR, as well as the operability of relevant structures, was assessed according to the grading scale proposed by Ammirati in 1998 and modified by Salma in 2011.

Results: Through the endonasal approach, the SSICR was entirely visualized. The optic nerves (ONs) and inferior aspect of the chiasm, pituitary stalk (PS), sellar diaphragm (SD), and superior hypophyseal artery (SHA) could be easily manipulated (grade 3 for midline structures; grade 5 for paired structures). The retrochiasmatic area was reached without pituitary transposition. The pterional approach provided the following results: Grade 5 for ON, grade 3 for the chiasm (superior aspect) and PS, and grade 2 for SD and SHA (difficult manipulation). The ipsilateral retrochiasmatic area was partially visualized on opening the Liliequist’s membrane. The subfrontal corridor provided a similar score when compared with the pterional. However, the retrochiasmatic area could be accessed bilaterally on opening the lamina terminalis and the floor of the third ventricle through the carotid triangles.

Conclusion: Endonasal approach allows a direct, safer, and wider exposure of the SSICR and surrounding structures when compared with pterional and subfrontal approaches given the natural advantages of a midline route.