Optimizing Surgical Trajectories to the Petroclival Region: Anatomic Predictors and Access Enhancement With Modified...

Area of Science:

• Neurosurgery
• Skull Base Surgery
• Minimally Invasive Endoscopic Techniques

Background:

• Endoscopic transnasal surgery is a minimally invasive alternative for midline skull base lesions.
• Lateral access, especially behind the petrous internal carotid artery (ICA), is limited with current endoscopic approaches.
• The contralateral transmaxillary (CTM) approach offers a more direct trajectory but faces restrictions from anatomic barriers.

Purpose of the Study:

• To evaluate the contralateral transmaxillary-transpterygoid (CTMP) approach, with and without lateral buttress removal (CTMP-LBR).
• To determine if these modifications enhance surgical access to the petroclival region.
• To compare the efficacy of CTM, CTMP, and CTMP-LBR in cadaveric dissections and radiographic analyses.

Main Methods:

• Dissection of 10 formalin-fixed cadaveric specimens to compare CTM, CTMP, and CTMP-LBR approaches.
• Petrous bone drilling directed posterolaterally behind the petrous ICA.
• Radiographic analysis of 30 computed tomography angiography scans for measurements.

Main Results:

• Both CTMP and CTMP-LBR significantly increased retrocarotid petrous bone drilling access and surgical angle compared to CTM (P < .001).
• Cadaveric dissections showed 20% required CTM, 50% benefited from CTMP, and 30% required CTMP-LBR for adequate lateral access.
• Radiographic analysis indicated CTMP-LBR enabled a trajectory parallel to the petrous ICA with less soft tissue displacement.

Conclusions:

• Modifying the CTM approach with pterygoid drilling and optional lateral buttress removal improves retrocarotid access.
• Preoperative evaluation of the petrous ICA angle can aid in patient-specific planning for endoscopic petroclival surgery.
• The CTMP and CTMP-LBR approaches offer enhanced options for challenging petroclival region pathologies.