VARIANTS OF MASTOID AND OCCIPITAL EMISSARY FORAMENS AND THEIR CLINICAL CORRELATION

Purpose: Emissary foramens in the skull and emissary veins (EV), respectively, have been known for a long time, but their importance is often disregarded. In the present study, we introduce variants of occipital emissary foramens (OEF) unilaterally located on the left, close to оccipital condylе in a formation of three apertures that open together in a sinus near clivus. Material/Methods: Corpses of 30 dеad people were dissected in the Department of Anatomy, and standard techniques for soft tissue separation or maceration of the skull were used. After the removal of the calvaria, fixed bones of the skull were disarticulated. Foramens were cleaned using a double-ended probe, and depth and diameter measurements were performed using an atomical caliper. Results: We found variants of mastoid emissary foramens (MEF) situated into two groups, each of a couple of foramens. Their clinical significance is discussed, compared with existing experience and analysis of their phylogeny and embryogenesis. Conclusion: We introduce OEF and MEF to be important markers for detection of dural venous sinuses (DVS). The latter, together with EV, provide an important mechanism for decreasing intracranial pressure. This happens due to the absence of a valve apparatus in the veins of the brain, and the lack, or small amount, of muscle tissue. There is a possibility of existing varicose veins, such as those caused by arterio-venous fistulas and the pathology associated with it. We suggest the application of EV in imaging as an important study before surgery by lateral and transcondylar approach to the anterior foramen magnum.

Long-term survival in patients with long-segment complex meningiomas occluding the dural venous sinuses: illustrative cases

BACKGROUND Invasive sagittal sinus meningiomas are difficult tumors to cure by resection alone. Stereotactic radiosurgery (SRS) can be used as an adjuvant management strategy to improve tumor control after incomplete resection. OBSERVATIONS The authors reported the long-term retrospective follow-up of two patients whose recurrent parasagittal meningiomas eventually occluded their superior sagittal sinus. Both patients underwent staged radiosurgery and fractionated radiation therapy to achieve tumor control that extended to 20 years after their initial surgery. After initial subtotal resection of meningiomas that had invaded major cerebral venous sinuses, adjuvant radiosurgery was performed to enhance local tumor control. Over time, adjacent tumor progression required repeat SRS and fractionated radiation therapy to boost long-term tumor response. Staged multimodality intervention led to extended survival in these patients with otherwise unresectable meningiomas. LESSONS Multimodality management with radiosurgery and fractionated radiation therapy was associated with long-term survival of two patients with otherwise surgically incurable and invasive meningiomas of the dural venous sinuses.

Superior sagittal sinus thrombosis in childhood – a case report

Cerebral venous sinus thrombosis (CVST) is presence of a blood clot in the dural venous sinuses. This is a rare, but dangerous condition. CSVT is characterized by a highly variable clinical spectrum, difficult diagnosis, variable etiologies and prognosis. The International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT) determined the frequency of the sites of SCVT. The aim of this case study was to show the clinical presentation, the examination we made, the therapy that was ordinated and the outcome of the treatment. Case study: A 14-year-old male teenager was admitted to the University Clinic for Neurosurgery in Skopje with GCS 10, accompanied with tonic-clonic epileptic seizures. CT examinations by systems were made, and during the time of recording the patient was given Dormicum 2mg overall dose. CT scan of the brain showed hyperdense zones formation around superior sagittal sinus (SSS), the rest of the medical finding was normal. We ran laboratorytests and the test for hemostasisshowed deviation from the normal range. With the ordinated therapy the clinical condition of the patient drastically improved. He was discharged home 12 days after the admission. He was given a recommendation for further check-ups by a transfusiologist and regular visits to our clinic. Occlusion of the cerebral veins and dural venous sinuses may occur on the basis of local trauma, neoplasm or infection. Primary aseptic thrombosis may involve either cerebral veins or dural venous sinuses, or both in combination. The clinical picture and the prognosis of intracranial venous thrombosis probably depend largely on the location, extent, and rapidity of development of the venous occlusion. Conclusion: Superior sagittal sinus thrombosis is a condition that can be manifested with diverse and many symptoms and signs, which often can start unexpectedly and can be life-threatening.

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.

Retrograde cerebral venous air embolism and the anatomical pathway of air bubbles: a case report

Pneumocephalus due to cerebral venous air embolism is an uncommon phenomenon. It results from retrograde progression of low weight air bubbles into dural venous sinuses during manipulation of a venous catheter, more frequently a central venous catheter through the subclavian and the jugular veins. However, it may also occur in relation with a peripheral intravenous catheter as in our case. We report a 91 year old female patient with congestive heart failure who had been examined in our emergency department two days previously due to dyspnea and received diuretic treatment through a peripheral intravenous line. She presented with vomiting and headache without obvious neurological deficits. Non-contrast cranial CT scan revealed wide spread punctate air bubbles inside and outside the cranial vault (pneumocephalus), within the venous system. The pneumocephalus was considered as iatrogenic due to the previous peripheral venous catheterization that resulted in retrograde migration of air bubbles through various venous connections into dural venous sinuses and extracranial veins. Since cerebral venous air embolism is a potentially serious complication of various medical procedures, it should be considered in differential diagnosis of nontraumatic headache and vomiting especially when there is a recent manipulation of venous lines. Cranial CT scan is helpful for early diagnosis.

Anatomic Variations of the Dural Venous Sinuses: A Primer for the Practicing Neuroradiologist

The dural venous sinuses exhibit considerable anatomic variation. Firm knowledge of dural venous sinus anatomy and common anatomic variants is of importance for the practicing neuroradiologist to recognize normal variants from pathologic conditions. In this article, we review dural venous sinus anatomy and present common variants through an image-based approach.Learning Objective: Review normal intracranial dural venous system anatomy and common variants.