Approach through the intraparietal sulcus to the ventricular atrium: A cadaveric microanatomical and morphometric study

Background: The intraparietal sulcus (IPS) provides a natural transsulcal corridor to the lateral ventricular atrium that minimizes disruption of white matter tracts. However, no previous study has quantified the dissection angles from multiple topographic points along the sulcus. Methods: Descriptive study conducted in the 9 adult human cerebral hemispheres available for dissection. IPS macroscopic morphology was classified and its length was measured. From the anterior, midpoint, and posterior points of the sulcus, straight pins were directed toward the ventricular atrium, and their angles relative to the anterior-posterior commissure line were measured. Subsequently, the depth was measured from each point to the atrium. Means, standard deviations (SD), ranges, and coefficients of variation (CV%) were calculated. Results: The IPS exhibited continuous morphology in all hemispheres, with a mean length of 3.96 ± 0.71 cm and a mean of 3.22 ± 0.97 accessory branches. Angular data were obtained in 6 of 9 hemispheres. Mean dissection angles were 4.5 ± 15.9° from the anterior point, 19.33 ± 11.99° from the midpoint, and 29.33 ± 12.14° from the posterior point. Approach depth, determined in 8 of 9 hemispheres, was 4.86 ± 0.74 cm, 5.24 ± 0.79 cm, and 5.4 ± 0.82 cm from the anterior, midpoint, and posterior points, respectively. Conclusion: IPS surface morphology and approach depth showed moderate interindividual variability, whereas dissection angles showed high variability, supporting the need for individualized presurgical trajectory planning. Based on the limited specimens available, these preliminary findings warrant validation in larger cohorts.