Superior Sagittal Sinus: A Review of the History, Surgical Considerations, and Pathology

Idiopathic intracranial hypertension secondary to Superior Sagittal Sinus Stenosis: a case report

INTRODUCTION

Idiopathic intracranial hypertension (IIH) is a disease characterized by elevated intracranial pressure (ICP) without established etiology. Venous sinus stenosis contributes to IIH; however, it is still uncertain whether the stenosis is a primary cause of IIH or a secondary result in response to elevated ICP. Transverse sinus stenosis is frequently identified in patients with IIH and it is suggestive of raised ICP. Here, we report a case of IIH caused by intrinsic superior sagittal sinus stenosis (SSS).

CASE PRESENTATION

A 43-year-old man suffered from IIH with headache, papilledema, and visual impairment. Angiography demonstrated isolated SSS stenosis with a pressure gradient of 30 mmHg. SSS stenosis was resistant to revascularization by stenting alone and intrastent balloon angioplasty was then performed to overcome such resistance. The rigidity of the vein wall suggests that the vein is not collapsed and the stenosis is intrinsic, secondary to idiopathic anatomical local changes. Post-procedure headache disappeared and visual acuity improved.

CONCLUSION

An isolated SSS stenosis could lead to intracranial hypertension and this condition should be taken into account in the diagnostic workup of IIH. By now, SSS stenosis is not mentioned in any current consensus guidelines or paper on the diagnostic workflow of intracranial hypertension.

Morphometric CT angiographic study of the SSS and its adjacent structures: A comparative analysis between elderly and nonelderly individuals of a Han Chinese population

Objective

The superior sagittal sinus (SSS) is an important structure, but few studies have analyzed it using computed tomography angiography (CTA).

Methods

This study was performed to examine the angiographic anatomy of the SSS and its adjacent structures using CTA in Han Chinese participants. According to age, participants were divided into elderly and nonelderly groups. The parameters of the SSS and adjacent structures were measured, recorded and analyzed statistically.

Results

A total of 500 Han Chinese participants were enrolled in this study, including 346 in the elderly group and 154 in the nonelderly group. In the elderly group, regarding inferior sagittal sinus (ISS) development, 187 ISSs were absent, 85 were visible, and 74 were clear. In the nonelderly group, 62 ISSs were absent, 54 were visible, and 38 were clear. In the elderly group, the Rolandic bridging vein diameter was 3.6 ± 0.8 mm; in the nonelderly group, the diameter was 3.9 ± 1.1 mm. The statistical results showed a difference in ISS development between the elderly and nonelderly groups (P < 0.05). The relationship of age with ISS development was assessed using linear regression analysis, and the results indicated that ISS became gradually occluded with age (P < 0.05). The statistical results also showed a difference in the Rolandic bridging vein diameter between the elderly and nonelderly groups (P < 0.05). The relationship of age with the Rolandic bridging vein diameter was assessed using linear regression analysis, and the results indicated that the Rolandic bridging vein tended to become thinner with age (P < 0.05).

Conclusion

This study found that more ISSs may become occluded and that the Rolandic bridging vein may become thinner with age. Other parameters of the SSS and its adjacent structures may not be affected by aging. In addition, our study also provided normal CTA parameters of the SSS and its adjacent structures in Han Chinese people.

Cardiac and Respiratory Influences on Intracranial and Neck Venous Flow, Estimated Using Real-Time Phase-Contrast MRI

The study of brain venous drainage has gained attention due to its hypothesized link with various neurological conditions. Intracranial and neck venous flow rate may be estimated using cardiac-gated cine phase-contrast (PC)-MRI. Although previous studies showed that breathing influences the neck’s venous flow, this aspect could not be studied using the conventional segmented PC-MRI since it reconstructs a single cardiac cycle. The advent of real-time PC-MRI has overcome these limitations. Using this technique, we measured the internal jugular veins and superior sagittal sinus flow rates in a group of 16 healthy subjects (12 females, median age of 23 years). Comparing forced-breathing and free-breathing, the average flow rate decreased and the respiratory modulation increased. The flow rate decrement may be due to a vasoreactive response to deep breathing. The respiratory modulation increment is due to the thoracic pump’s greater effect during forced breathing compared to free breathing. These results showed that the breathing mode influences the average blood flow and its pulsations. Since effective drainage is fundamental for brain health, rehabilitative studies might use the current setup to investigate if respiratory exercises positively affect clinical variables and venous drainage.

Mechanical and structural characterisation of the dural venous sinuses

The dural venous sinuses play an integral role in draining venous blood from the cranial cavity. As a result of the sinuses anatomical location, they are of significant importance when evaluating the mechanopathology of traumatic brain injury (TBI). Despite the importance of the dural venous sinuses in normal neurophysiology, no mechanical analyses have been conducted on the tissues. In this study, we conduct mechanical and structural analysis on porcine dural venous sinus tissue to help elucidate the tissues’ function in healthy and diseased conditions. With longitudinal elastic moduli values ranging from 33 to 58 MPa, we demonstrate that the sinuses exhibit higher mechanical stiffness than that of native dural tissue, which may be of interest to the field of TBI modelling. Furthermore, by employing histological staining and a colour deconvolution protocol, we show that the sinuses have a collagen-dominant extracellular matrix, with collagen area fractions ranging from 84 to 94%, which likely explains the tissue’s large mechanical stiffness. In summary, we provide the first investigation of the dural venous sinus mechanical behaviour with accompanying structural analysis, which may aid in understanding TBI mechanopathology.

Dural Venous Sinuses: What We Need to Know

BACKGROUND

The dural venous sinuses (DVS), in general, are frequently asymmetrical and display far more anatomical variations than arterial systems. A comprehensive study of the anatomy and variants of the DVS can help surgeons in the preoperative evaluation and management as well as minimizing possible complications in the following treatment.

METHODS

The current review was designed to provide a general overview of the normal anatomy and notable variants of the cerebral venous system as surveyed from the available literature. The pros and cons of different multimodal imaging methods for investigating DVS are also outlined. Finally, cases of various pathological entities are illustrated from our clinical practice.

CONCLUSION

There are many anatomical variations and lesions involving the DVS. MRI examination can provide essential information both on anatomical variation and morphological or functional change of the offending DVS in most circumstances. Multimodal non-invasive venography protocols may become a feasible alternative to the classical digital subtraction angiography and would improve the diagnostic accuracy in future studies.