Volume of Operative Maneuverability as a New Measurement in Neuroanatomical Research: A Methodological Quantitative...

The lack of standardized metrics in neuroanatomical research limits the objective assessment of neurosurgical approaches. We introduce a novel volume-based parameter, the Volume of Operative Maneuverability (VOM), and evaluate its utility in quantifying surgical corridor dimensions.

Seven microscopic and endoscopic skull base approaches were performed on 4 embalmed latex-injected human cadaveric specimens. A spatial principal component analysis algorithm converted surgical entry and target areas into ellipses, allowing ellipsoidal-based VOM calculations. Corridor length ("target distance") and a fixed 10 mm distance from the target ("standardized VOM" [sVOM]) were also measured. Feasibility and reproducibility were assessed using three-dimensional photogrammetry, preoperative imaging models, and a clinical case.

Endoscopic endonasal and anterior transmaxillary approaches offered sufficient corridor volume and trajectory distance but created longer, narrower surgical corridors with lower sVOM than transcranial approaches. Conversely, pretemporal-orbitozygomatic and subtemporal corridors showed the highest VOM and sVOM. Illustrative examples confirmed consistent measurement in photogrammetry and preoperative imaging. A clinical case involving a right spheno-cavernous meningioma demonstrated a VOM of 2.328 cm³, sVOM of 0.615 cm³, and a target distance of 18 mm during extradural anterior clinoidectomy.

VOM provides a quantitative, reproducible metric for assessing surgical maneuverability toward irregular target surfaces, overcoming the limitations of traditional qualitative assessments. Preliminary data support its use in quantitative neuroanatomical research and suggest potential integration into surgical planning and intraoperative data collection.