J Neurol Surg B Skull Base 2015; 76 - P031
DOI: 10.1055/s-0035-1546659

Endoscopic Endonasal Study of the Cavernous Sinus and Quadrangular Space: Anatomical Relationships

Ricardo L. Dolci 1, Ricardo L. Carrau 1, Smita Upadhyay 1, Leo F. Ditzel 1, Mariano E. Fiore 1, Lamia Buohliqah 1, Gerival Vieira Junior 1, Paulo R. Lazarini 2, Bradley A. Otto 1, Daniel M. Prevedello 1
  • 1Ohio State University, Ohio, United States
  • 2Santa Casa Misericórdia de São Paulo, São Paulo, Brazil

Background: Expanded endoscopic endonasal approaches have evolved over the last decade to grant access to virtually every region of the ventral skull base. The so-called quadrangular space permits an anterior entry into Meckel Cave while obviating the need for cerebral or cranial nerve retraction. This avenue is surrounded by the cavernous sinus and associated landmarks; therefore, from the ventral perspective, it is feasible to visualize the anteromedial, Parkinson and anterolateral triangles. Knowledge of these relations is paramount during endonasal endoscopic surgery around this region.

Objective: This study aims to describe anatomical relationships of the quadrangular space and cavernous sinus landmarks from a ventral perspective.

Methods: A total of 12 middle cranial fossae, in 6 adult human cadaveric specimens, were dissected endonasally under direct endoscopic visualization. Measurements of the surface area of the quadrangular space and of the ventrally accessible cavernous sinus triangles were performed utilizing three coordinates under image-guided navigation. The relationship between the quadrangular space and the petrous, paraclival, and cavernous segments of the internal carotid artery (ICA) was also noted.

Results: The quadrangular space is limited superiorly by the abducens nerve, medially by the paraclival ICA, laterally by the maxillary nerve and inferiorly by the petrous ICA. The trajectory of the ICA, particularly in its paraclival segment, significantly impacts the surface area of the quadrangular space (16.00 + 3.44 mm2). The anterolateral triangle was the largest (47.85 + 5.95 mm2), whereas the Parkinson triangle was the smallest (22.45 + 6.10 mm2); the anteromedial triangle presented on average 34.76 mm2 of surface area (+ 4.04 mm2).

Conclusion: The surface area of the ventral face of the quadrangular space and ventrally accessible cavernous sinus triangles present some variation of among specimens. These are similar to those reported in previous transcranial cadaveric studies. The trajectory of the ICA significantly impacts the quadrangular space area and may be a potential parameter for defining the feasibility of this corridor.