Morphometric Analysis of the Posterior Wall of the Cavernous Sinus

Keywords

cavernous sinus - posterior wall of cavernous sinus - ICA - PPC ligament - skull base anatomy

Background: Both sellar and parasellar tumors may extend into the posterior compartment of the cavernous sinus, becoming a potential pathway for the tumor to extend into the middle fossa or Sella, respectively. Moreover, the posterior wall of this compartment is the natural barrier to the posterior fossa, with significant repercussions to resectability, if invaded. The goal of this study is to perform a morphometric analysis of the posterior wall of the cavernous sinus and adjacent structures.

Materials and Methods: Measurements of the posterior wall of the cavernous sinus were performed using a neuronavigation system (Stealth Station S7 Surgical Navigation System; Medtronic, Dublin, Ireland) to get predetermined data points on six alcohol- fixed human heads (12 sides). The tip of the neuronavigation probe was placed at different points: The most cranial insertion of the Posterior Petroclinoid Ligament (PPC) into the Posterior Clinoid process, The base of the Petrosal process of sphenoid bone (PPsb) and the petrous apex. Additional points were considered to measure the distance from the paraclival Internal Carotid Artery (ICA) to the Posterior Wall of the Cavernous Sinus (PW CS) at four separate places. The emergency angle of the Posterior Petroclinoid Ligament (PPC) from the petrous apex was also measured. These measures allowed us to get the data of the perimeter and the area of the PW CS, the emergency angle degree of the PPC ligament from the petrous apex, the measures of the medial, inferior, and superior limit of the PW CS as well as the distance from the ICA to the Trigeminal porus.

Results: The PW CS has a triangular shape area measuring (65 mm ± 3.55 mm2), with a perimeter of (38 mm ± 2.5 mm). The medial limit measure was (11.45 mm  ± 1.85 mm) in the craniocaudal axis. In the horizontal plane, the inferior limit measures (11.25 mm  ± 1 mm), the external limit measure was (5.85 mm ± 3 mm) and the posterior-superior limit measure was (15.75 ± 2.65 mm). The PPC ligament angle emergency was (45° ± 5°) with a trajectory from inferior to superior, from lateral to medial and from posterior to anterior. From the sagittal plane, the paraclival ICA-PW CS distance was: Upper-Medial: (2.81 mm ± 1.6 mm). Upper-Lateral: (4.33 mm ± 1.6 mm). Inferior-Medial: (3.91 mm ± 1 mm). Inferior-Lateral: (4.55 mm ± 1 mm). The distance from the medial side of the Porus Trigeminus to the lateral border of the Paraclival ICA is (2.5 mm ± 1 mm), range of (4. mm to 1.5 mm).

From the PPsb to the Medial limit of the Porus Trigeminus distance: (5.3 mm ± 1 mm).

Conclusion: The posterior wall of the Cavernous Sinus is a triangular shape area with limits of regular measurements. This structure is of paramount importance due to its proximity to the posterior fossa.

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No conflict of interest has been declared by the author(s).

Publication History

Article published online:
05 February 2024