Image-Guided Comparative Morphometric Study of the Supraorbital, Transorbital, and Pterional Approaches to the Sellar and Perisellar Regions

Introduction: Minimally invasive approaches have been proposed for the treatment of anterior skull base pathology. In this cadaveric morphometric study, we undertook the task to systematically quantify and compare the operative exposure afforded by the pterional, supraorbital, and transorbital keyhole approaches to the sellar, suprasellar, and perisellar regions, including the anterior communicating artery complex.

Methods: Pterional, supraorbital, and transorbital approaches were sequentially performed in five embalmed cadaveric heads on both sides. Postoperative computerized tomography scans were performed and used for frameless stereotactic navigation and measurements. Using reproducible anatomical landmarks, six triangles were defined to systematically measure the working area, depth of surgical window, and angle of observation for each approach. The areas of the triangles were calculated using Heron's mathematical formula based on stereotactic navigation measurements. Ten sets of data were obtained and subjected to analysis.

Results: The pterional, supraorbital, and transorbital keyhole approaches provided progressively increasingly large working areas. The transorbital approach was associated with significantly increased exposure when compared with the pterional approach (p < 0.001). The transorbital approach was associated with shallower depth of surgical window when compared with both supraorbital (p < 0.005) and pterional approaches (p < 0.001). The angle of basal view increased 56.6% with the transorbital approach (p < 0.001) when compared with the supraorbital approach. The transorbital route provided greater exposure on deeply located midline and contralateral structures.

Conclusion: Morphometric data support the use of the transorbital approach for treatment of sellar and perisellar pathologies. The transorbital approach combines the advantages of minimal invasiveness with those of skull base techniques.