2025 Poster Presentations
P126: ANATOMY OF THE PETROSAL FISSURE: IMPLICATIONS FOR SKULL BASE SURGERY
Maged T Ghoche, MD; Maria José Pachón-Londoño, MD; Vita A Olson; Estefana Bcharah; Abhijith R Bathini, MD; Charbel Moussalem, MD; Devi P Patra, MD; Bernard R Bendok, MD, MSCI; Mayo Clinic
Introduction: The petrosal fissure, the most distinct, largest, and deepest fissure of the cerebellum, plays a crucial role in skull base surgery. Understanding its detailed anatomy is essential for neurosurgeons to navigate this region safely and effectively. This review aims to provide a comprehensive analysis of the petrosal fissure's anatomy, highlighting its relevance to surgical approaches and implications for clinical practice.
Objectives: To delineate the anatomical features of the petrosal fissure and explore its significance in surgical procedures involving the cerebellopontine angle and surrounding structures.
Methods: A literature review of PubMed, Scopus, and Google Scholar was conducted, focusing on articles published prior to 2024. Cadaveric and clinical studies focusing on cerebellar anatomy, neurovascular relationships, and surgical techniques were included. Data were synthesized to provide a detailed description of the petrosal fissure and its clinical significance.
Results: In total, 12 clinical studies and 9 cadaveric were retrieved. The anatomical analysis of the petrosal fissure reveals the following key features:
Location and Structure: The cerebellopontine fissure is a V-shaped fissure that delineates the petrosal surface of the cerebellum from the middle cerebellar peduncle and the pons. In 10 cadaveric heads, the petrosal fissure extended laterally and symmetrically from the apex of the cerebellopontine fissure and run 0.5 to 1 cm caudal to the petrosal-tentorial junction, separating the cerebellum into superior and inferior semilunar lobules. The length of the petrosal fissure ranged from 15.9 mm to 23 mm, with an average depth of 14 mm.
Neurovascular Structures: Venous Anatomy: The vein of the cerebellopontine fissure, originating in the suprafloccular cistern, courses along the superior limb of the cerebellopontine fissure and drains into the superior petrosal vein. In 15 patients and 8 cadaveric heads, 77% had a single superior petrosal vein (SPV); 20% had SPVs; and 3% had three SPVs. In 50 patients, this vein has several tributaries with 29 variations, including the vein of the cerebellomedullary fissure, lateral medullary vein, vein of the pontomedullary sulcus, and vein of the middle cerebellar peduncle.
Arterial Anatomy: In 10 cadaveric heads, 25% of the petrosal aspect of the fissure receives a major tributary from the lateral branch of the AICA, and in 50% of cases, smaller branches of the AICA pass into the fissure. Occasionally, one or more cortical branches of the SCA extend into the petrosal fissure.
Surgical Approaches: The petrosal fissure provides access to the middle cerebellar peduncle, lateral pons, and cranial nerves in the cerebellopontine angle. Splitting the fissure allows for a direct lateral approach, minimizing cerebellar retraction and reducing the risk of injury to vital structures.
Conclusion: A detailed understanding of the petrosal fissure's anatomy is vital for neurosurgeons performing skull base surgeries. The fissure's location, structure, and surrounding neurovascular relationships must be carefully considered to optimize surgical outcomes and minimize complications. Further anatomical studies and advanced imaging techniques are recommended to enhance the precision of surgical interventions in this complex region.