Response to the Letter to the Editor: “Morphological Variability of Dural Venous Sinus Grooves and Internal Bony Findings: Clinical and Surgical Considerations”

10.1055/a-2697-4511

We are grateful to Cardona et al[1] for their thoughtful comments on our recent article, “Anatomical Variability of the Transverse and Sigmoid Sinus Grooves: Implications for Skull Base Surgery.”[2] Their observations add valuable perspective and point toward essential avenues for future investigation.

One issue they raise concerns our decision not to specify the exact segmental locations of transverse and sigmoid sinus measurements. This is a fair observation. Our study of dried skulls was designed to present a broad morphometric overview of a Greek skeletal series, rather than a segmental analysis. We agree, however, that a segmental approach has clear clinical relevance, especially regarding venous sinus stenosis and thrombosis. Although dried skulls cannot provide lumen-based measurements like cadaveric or radiological methods, specific bony landmarks—such as the torcular Herophili, transverse–sigmoid junction, and jugular foramen—remain consistent and reproducible landmarks. These landmarks serve as stable reference points across populations, improving reproducibility, enabling comparisons between studies, and supporting large-scale morphometric analyses that are directly relevant to skull base surgery.

Cardona et al[1] also emphasize the absence of less common variants in our series, such as an oblique occipital sinus draining into the transverse sinus or the presence of granular foveolae.[3] [4] The fact that these morphological variants were not encountered likely reflects a combination of population-specific traits and sampling limitations, both of which we acknowledged in our discussion and methodology. Their absence should not be seen as diminishing their importance. On the contrary, documenting negative findings helps to define the baseline spectrum of cranial variation. Whether such variants are present or absent may be influenced by developmental factors, methodological approaches, and regional anatomy. As Cardona et al[1] note, these variants may have essential implications for venous outflow, potentially predisposing to thrombosis, stenosis, or pulsatile tinnitus. This highlights the value of comparative, multimodal studies across different populations.[3] [4] Our research[2] adds to this field by providing baseline population data on groove variability that can be directly used for surgical planning. This exchange emphasizes the importance of an evidence-based anatomical framework. Each methodology—dried skull morphometry, cadaveric dissection, and imaging—possesses distinct strengths and limitations. Dried skulls facilitate large-sample population-specific analysis of osseous grooves, which is particularly relevant for surgical approaches.[3] [4] Cadaveric studies offer unparalleled detail of venous walls, septa, and angulation; however, they are often limited by sample size.[5] Imaging provides in vivo and dynamic insights into venous anatomy and pathology; however, the fine details of bony landmarks may be less discernible or distinct. When combined, these approaches complement one another, and Cardona et al's[5] recent finding that venous angulation mirrors the corresponding bony grooves further supports the reliability of skeletal morphometry within this framework. Significantly, combining evidence from these methods improves both surgical planning and the creation of risk stratification models for cerebrovascular disease.

We also value Cardona et al's[1] emphasis on the clinical implications of venous variability. Their work on sinus angulation illustrates how specific morphologies may predispose to turbulent flow, venous stasis, and thrombosis. Likewise, their identification of the sigmoid sinus artery highlights the interaction between venous and arterial structures in operative fields. These findings underscore significant considerations regarding iatrogenic risk, as even minor anatomical variations can influence surgical pathways and modify vascular relationships in manners that are not always apparent on preoperative assessments imaging. Our descriptive morphometric data, when integrated with such micro-anatomical and hemodynamic studies, provide the basis for population-tailored risk assessment in skull base surgery.

In summary, we appreciate Cardona et al's[1] constructive feedback and view our findings as complementary to their work. By integrating skeletal morphometry, cadaveric dissections, and imaging studies within the framework of evidence-based anatomy, we can develop a more comprehensive understanding of dural venous sinus variability and its clinical significance. This exchange exemplifies how collaborative dialogue in anatomical research refines methodologies and promotes translation into neurosurgical practice. We invite further collaboration to enhance understanding of the relationship between cranial morphology, venous hemodynamics, and surgical implications.

Publikationsverlauf

Eingereicht: 19. September 2025

Angenommen: 22. September 2025

Artikel online veröffentlicht:
03. Oktober 2025

• References

• 1 Cardona J, Park D, Chang S, Iwanaga J, Tubbs R. Morphological variability of dural venous sinus grooves and internal bony findings: clinical and surgical considerations. J Neurol Surg Part B 2025
• 2 Triantafyllou G, Pishiaras H, Papadopoulos-Manolarakis P, Paschopoulos I, Tsakotos G, Piagkou M. Anatomical variability of the transverse and sigmoid sinus grooves: implications for skull base surgery. J Neurol Surg B Skull Base 2025
• 3 Guduri P, Ekanem UI, Shekhawat D. et al. Granular foveolae in the groove of the sigmoid sinus: an anatomical study. Cureus 2023; 15 (03) e36678
• 4 Cardona JJ, Iwanaga J, Chaiyamoon A. et al. Bony prominence and variations of the transverse sinus groove: novel anatomical findings in relation to sinus pathologies. Neurosurg Rev 2024; 47 (01) 869
• 5 Cardona JJ, Samrid R, Kim CY. et al. Angulation of the dural venous sinuses in the posterior cranial fossa: an anatomical study and its implications for venous circulation. Neurosurg Rev 2025; 48 (01) 66