2025 Proffered Presentations
S338: AN ANATOMICAL STUDY OF TRANSCRANIAL AND ENDOSCOPIC APPROACHES TO THE PONS: A 360º PERSPECTIVE
Yasaman Alam, MD1; Luciano Leonel, PhD2; Megan Bauman, BS2; Maria Peris-Celda, MD, PhD2; 1Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA; 2Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, Minnesota, USA
Background: Over the last twenty years, efforts have been made to develop safer approaches to pontine region. Access to the pons and surrounding areas remain amongst one of the most challenging approaches in neurosurgery. Pathologies such as cavernous malformation, intrinsic brain tumors, aneurysms, cerebellopontine angle and 4th ventricular tumors, require approaches not only to this area but also the pons and pre-pontine cistern.
Objective: In this study we aimed to compare and illustrate the surgical routes and corridors to the pons provided by different open and endoscopic approaches emphasizing their recommendations, limitations, and anatomical structures exposed.
Method: Six formalin-fixed and latex-injected cadaveric specimens were utilized in this study. Dissections were performed under microscope and endoscope for better visualization. To compare and illustrate the approaches and their different surgical corridors to the pons and pontine region, the following approached were performed: orbitozygomatic, pterional, subtemporal, anterior petrosectomy, retrosigmoid, telovelar, and far lateral approaches, as well as the endoscopic endonasal. The specimens were dissected within the lab and photo-documented using 3D techniques.
Result: Considering the approaches selected and described in this study (Figures 1-4), the pterional and orbitozygomatic (OZ) approaches provided anterolateral access to the upper portion of the pons and prepontine cistern. The subtemporal approach obtained excellent visualization of the lateral pons and a larger surface area was obtained in comparison to the pterional or OZ approaches. In addition, offering less retraction on the temporal lobe to access the lateral pons. The anterior petrosectomy provided access to the distal part of the anterolateral pons. The retrosigmoid approach provided access from the mid to lower basilar region, as well as offering a corridor to reach the posterolateral portion of the pons. The far lateral approach provided wider surface area to the posterolateral pons when compared to the retrosigmoid approach, while the telovelar approach provided excellent view of the lower portion of posterior pons. Lastly, with the endoscopic endonasal extradural transposition of the pituitary gland the ventral portion of the pons was visualized and also explored.
Conclusion: Different approaches can be used to gain access to the pons and its correlated anatomical structures. Knowledge of different degrees and surgical corridors provided by both transcranial and endoscopic approaches are key to select the safest and most suitable approach for each lesion respecting its pathology and guaranteeing a better outcome for the surgery and patient.
