Morphometric analyses of neurovascular triangles in pterional craniotomy: a cadaveric study in Eastern India

The pterional approach facilitate access to particular neurovascular structures through the optic-carotid and carotid-oculomotor triangles. Even with broad adoption, quantitative morphometric data remain limited, particularly in South Asian populations. Main objectives were to evaluate and compare the distance of optic-carotid (Triangle I) and carotid-oculomotor (Triangle II) triangles from internal aspect of pterion of both sides in cadaveric specimens using standardized pterional craniotomy techniques.

A cross-sectional cadaveric study was conducted on seven formalin embalmed adult specimens (14 sides of 3 males, 4 females) at a tertiary medical institution. Following standard pterional exposure, linear dimensions from internal aspect of pterion to proximity of the intracranial landmarks: (a) Optic-carotid triangle, (b) Carotid-oculomotor triangle, (c) Lateral border of optic nerve, (d) lateral border of optic canal were measured using digital callipers (± 0.01 mm precision). Statistical analysis included t-tests for comparisons of means.

Distance for Triangle I from internal aspect of pterion demonstrated significant large value on left-sided than right side (54.14 ± 5.44 mm vs. 46.14 ± 5.30 mm; p = 0.002; Cohen's d = 1.49). Triangle II showed similar asymmetric distance for left and right side from internal aspect of pterion (56.00 ± 6.95 mm vs. 47.14 ± 4.78 mm; p = 0.002; Cohen's d = 1.47). Landmarks for optic nerve and optic canal exhibited bilateral symmetry (p > 0.05). No significant sex-based differences were observed across parameters.

Significant large distance for left-sided neurovascular working triangles contrasts with symmetric nerve and bony landmarks, suggesting the need for subjective surgical planning in pterional approaches. These findings may have direct inferences for operative technique modification and surgical training.