Background: Over the last 20 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 prepontine 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.
Methods: 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 ([Figs. 1]
[2]
[3]
[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.
