The Confluence of the Superior Sagittal Sinus and the Vein of Trolard: A Radiographic Study.

BACKGROUND

The vein of Trolard (VoT), the largest superior superficial anastomotic vein, demonstrates variable anatomy at its confluence with the superior sagittal sinus (SSS). This confluence is classically located near the marginal sulcus but can occur anteriorly, increasing venous infarction risk. We aimed to characterize VoT displacement relative to the marginal sulcus, evaluating hemispheric asymmetry, sex, age and the effect of sagittal pathology.

METHODS

We conducted a single-center retrospective analysis using MRI. VoT entry sites were measured relative to the marginal sulcus by two independent interpreters. The Kolmogorov-Smirnov test compared entry distributions across non-pathology and pathology groups (p < 0.05).

RESULTS

We analyzed 390 subjects (780 hemispheres; mean age 57; 45% male), with sagittal pathology in 19%. High inter-rater reliability (R = 0.920 right; R = 0.918 left) permitted using averaged measurements. The VoT was significantly displaced anterior to the marginal sulcus (median 26.4 mm left [range 37.6 to 73.6 mm]; 24.5 mm right [range 49.9 to 79.1 mm]; p < 0.001). There was no significant hemispheric asymmetry (p = 0.37). Sex-based differences were significant bilaterally (p = 0.012 left; p = 0.0011 right). Entry locations differed significantly between pathology and non-pathology groups on the left (p = 0.00892) and right (p = 0.0265).

CONCLUSIONS

The VoT demonstrates consistent displacement from the marginal sulcus with a bimodal distribution, influenced by sex but not hemisphere. These findings highlight the importance of recognizing variability in venous anatomy to minimize the risk of misidentification and venous injury during neurosurgical intervention.