Evaluation of the Accuracy of 4 Conventional Freehand Frontal Ventriculostomy Methods in the Chinese Population

BACKGROUND AND OBJECTIVES: In conventional freehand frontal ventriculostomy, the Kocher point is the entry point, the external auditory canal is the sagittal target, and the coronal targets include the ipsilateral medial canthus (IMC), the midpoint between the bilateral external auditory meatus (MAM), the contralateral medial canthus (CMC), and the region perpendicular to the skull (P). The aim of this study was to calculate puncture accuracy of the 4 conventional methods to guide clinical selection. METHODS: Patient data from thin-slice computed tomography scans were imported, and a 3-dimensional model was reconstructed using software to simulate puncture. The accuracy and puncture depth of the 4 freehand frontal ventriculostomy methods were analyzed. RESULTS: From January 1, 2022, to December 30, 2023, 520 patients were screened and 206 were enrolled; 137 (66.5%) participants were males, and 69 (33.5%) were females. The median age of the patients was 64 years (IQR 53-73). The maximal frontal horn width was 21.7-53.7 mm (IQR 34.4-40.0), and the intercanthal distance was 26.0-43.2 mm (IQR 30.7-34.9). Simulating bilateral ventricular puncture, for the IMC trajectory, the puncture accuracy was 13.3% (55/412) [95% CI 10.4-17.0] and the puncture depth was 41.8 ± 4.6 mm. For the MAM trajectory, the puncture accuracy was 74.5% (307/412) [95% CI 70.1-78.5] and the puncture depth was 43.6 ± 4.3 mm. For the P trajectory, the puncture accuracy was 90.5% (373/412) [95% CI 87.3-93.0] and the puncture depth was 49.4 ± 5.9 mm. For the CMC trajectory, the puncture accuracy was 100.0% (412/412) [95% CI 99.1-100.0] and the puncture depth was 47.2 ± 5.2 mm. CONCLUSION: Compared with the MAM trajectory, the CMC and P trajectories were more reliable in frontal ventriculostomy, but the P trajectory may enter the contralateral ventricle. The IMC trajectory is not recommended unless the frontal horn is wider than 45 mm or the Kocher point is moved inward.