Revisiting the rules for freehand ventriculostomy: a virtual reality analysis

Area of Science:

• Neurosurgery
• Medical Imaging
• Anatomy

Background:

• Frontal ventriculostomy is a frequent neurosurgical procedure.
• Catheter misplacement or suboptimal placement is a common challenge.

Purpose of the Study:

• To reexamine landmarks and rules for frontal ventriculostomy.
• To determine the optimal entry point and trajectory for the highest hit rate (HtR).

Main Methods:

• Utilized CT scans from 50 patients with normal anatomy.
• Simulated 8000 virtual ventriculostomies using a 5x5 cm frontal grid with 25 entry points.
• Investigated perpendicular, landmark-based, and idealized trajectories toward the ipsilateral anterior horn (ILAH).

Main Results:

• The highest HtR for the ILAH was 86% with an ideal trajectory.
• Optimal HtRs were achieved with specific pairings of entry points (e.g., 3-4 cm lateral to midline) and trajectories (e.g., toward contralateral canthus).
• The ipsilateral medial canthus showed surprisingly low HtRs and is not recommended.

Conclusions:

• Few entry points and specific trajectories achieve >80% HtR for ILAH.
• A critical "pairing" between entry point and trajectory was identified for both landmark and perpendicular approaches.
• Commonly used landmarks like the ipsilateral medial canthus may not be optimal for trajectory targeting.