Angulation of the dural venous sinuses of the posterior cranial fossa: Anatomical study with clinical and surgical applications.

Cerebral vein and dural venous sinus thromboses (CVST) account for 0.5%-1% of all strokes. Some structural factors associated with a potentially higher risk for developing CVST have been described. However, angulation of the dural venous sinuses (DVS) has yet to be studied as a structural factor. The current study was performed because this variable could be related to alterations in venous flow, thus predisposing to a greater risk of CVST development. Additionally, such information could help shed light on venous sinus stenosis (VSS) at or near the transverse-sigmoid junction. The angulations formed in the different segments of the grooves of the transverse (TS), sigmoid (SS), and superior sagittal sinuses (SSS) were measured in 52 skulls (104 sides). The overall angulation of the TS groove was measured using two reference points. Other variables were examined, such as the communication pattern at the sinuses' confluence and the sinus grooves' lengths and widths. The patterns of communication between sides were compared statistically. The most typical communication pattern at the sinuses' confluence was a right-dominant TS groove (82.98%). The mean angulations of the entire left TS groove at two different points (A and B) were 46° and 43°. Those of the right TS groove were 44° and 45°. The median angulations of the left and right SSS-transverse sinus junction grooves were 127° and 124°. The mean angulations of the left and right TS-SSJsv grooves were 111° (range 82°-152°) and 103° (range 79°-130°). Differentiating normal and abnormal angulations of the DVSs of the posterior cranial fossa can help to explain why some patients are more susceptible to pathologies affecting the DVSs, such as CVST and VSS. Future application of these findings to patients with such pathologies is now necessary to extrapolate our results.

An anatomical study of the sigmoid sinus artery: Application to the transmastoid approach.

INTRODUCTION: We aimed to investigate the morphological features of the artery that traverse the sigmoid sinus's lateral surface and to discuss this structure's clinical relevance. METHODS: Ten sides from five cadaveric Caucasian heads were used for gross anatomical dissection to investigate the morphological features of the sigmoid sinus artery (SSA), and additional five sides were used for histological observation. RESULTS: The SSA was found on eight out of ten sides (80%). The mean diameter of the SSA was 0.3 mm. The mean distance from the tip of the mastoid process to the artery was 20.3 mm. Histological observation identified extradural and intradural courses of SSA. The intradural course was further categorized into protruding and non-protruding types. In the protruding type, the SSA traveled within the dura but indented into the bone, making it more or less an intraosseous artery. In the non-protruding type, the SSA traveled within the dura but did not protrude into the bone but rather indented into the lumen of the SS. In all sections, both intradural and extradural courses were identified simultaneously. CONCLUSIONS: When the mastoid foramen is observed, it does not always only carry an emissary vein but also an artery. The SSA could be considered a "warning landmark" during bone drilling for the transmastoid approach.

Dural sinus septum as an underlying cause of intrinsic venous sinus stenosis: Anatomical, clinical, and stent placement considerations.

Recently, an interesting study regarding "Dural sinus septum: an underlying cause of cerebral venous sinus stenting failure and complications." was published, to our knowledge, being the launching point of the clinical/interventional applications of this intraluminal variation. Herein, we wish to highlight paramount anatomical, clinical, and stent placement considerations related to DSS located in the dural venous sinus at the posterior cranial fossa and the interventional complications caused by the presence of this variation during stenting procedures.

Trabeculae in the basilar venous plexus: anatomical and histological study with application to intravascular procedures.

Few studies have examined the basilar venous plexus (BVP) and to our knowledge, no previous study has described its histology. The present anatomical study was performed to better elucidate these structures. In ten cadavers, the BVP was dissected. The anatomical and histological evaluation of the intraluminal trabeculae within this sinus were evaluated. Once all gross measurements were made, the clivus and overlying BVP were harvested and submitted for histological analysis. A BVP was identified in all specimens and in each of these, intraluminal trabeculae were identified. The mean number of trabeculae per plexus was five. These were most concentrated in the upper half of the clivus and were more often centrally located. These septations traveled in a posterior to anterior direction and usually, from inferiorly to superiorly however some were noted to travel horizontally. In a few specimens the trabeculae had wider bases, especially on the posterior attachment to the meningeal layer of dura mater. More commonly, the trabeculae ended in a denticulate form at their two terminal ends. The trabeculae were on average were 0.85 mm in length. The mean width of the trabeculae was 0.35 mm. These septations were consistent with the cords of Willis as are found in the lumen of some of the other intradural venous sinuses. An understanding of the internal anatomy of the BVP can aid in our understanding of venous pathology. Furthermore, this knowledge will benefit patients undergoing interventional treatments that involve the BVP.

Sequential Flow Diversion After Nitinol Stent Placement for a Large, Matricidal Cavernous Internal Carotid Artery Aneurysm: Technical Video.

The Surpass Evolve flow diverter is a novel 64-wire braided intravascular stent approved to treat unruptured large or giant saccular wide-neck or fusiform intracranial aneurysms of the intracranial internal carotid artery.1-3 Flow diverting stents have been used for the treatment of previously stented aneurysms, including residual aneurysms following prior flow diversion.5-8 This patient initially presented with a large symptomatic matricidal cavernous ICA aneurysm4 that was treated with stand-alone Neuroform Atlas stenting at an outside hospital. Here we present a video demonstrating the placement of sequential Surpass Evolve flow diverter stents within a Neuroform Atlas nitinol stent.

Woven EndoBridge Embolized Aneurysm Clippings: 2-Dimensional Operative Video.

The Woven EndoBridge (WEB) device (MicroVention, Aliso Viejo, California) is an intrasaccular flow disruptor used for the treatment of both unruptured and ruptured intracranial aneurysms. WEB has been shown to have 54% complete and 85% adequate aneurysm occlusion rates at 1-yr follow-up.1 Residual and recurrent ruptured aneurysms have been shown to have a higher risk of re-rupture than completely occluded aneurysms.2 With increased utilization of WEB in the United States, optimizing treatment strategies of residual aneurysms previously treated with the WEB device is essential, including surgical clipping.3,4 Here, we present an operative video demonstrating the surgical clip occlusion of previously ruptured middle cerebral artery and anterior communicating artery aneurysms that had been treated with the WEB device and had sizable recurrence on follow-up angiography. Informed consent was obtained from both patients. Lessons learned include the following: (1) the WEB device is highly compressible, unlike coils; (2) proximal WEB marker may interfere with clip closure; (3) no evidence of WEB extrusion into the subarachnoid space; (4) no more scarring than expected in ruptured cases; and (5) clipping is a feasible option for treating WEB recurrent or residual aneurysms.

Mercury vs. Water: An Analysis of Multi-Institutional Survey Data Assessing Intracranial Pressure Unit of Measure Awareness.

BACKGROUND: Intracranial pressure (ICP) reporting impacts neurosurgical care. Millimeters of mercury (mmHg) and centimeters of water (cmH2O) are both used to report ICP in clinical practice and the literature. In this study, we investigated ICP unit of measure awareness in the neurosurgical community. METHODS: A survey was conducted at four US academic neurosurgery departments asking the following questions: What is your threshold for a concerning ICP? How many minutes is that ICP sustained for you to be concerned? What unit are you implying when you state that ICP? What unit of measure is an ICP reported on the monitor when transduced? When setting an external ventricular drain Becker bag level, what unit of measure do you set it to? Do you ever manually check an ICP based on a column of cerebrospinal fluid? How many cmH2O is 20 mmHg? RESULTS: An ICP of 20 and sustained for five minutes were the two most common answers. Some 71% of residents and 34% of attendings reported using cmH2O as the unit of measure; 18% of residents and 24% of attendings implied different units when discussing ICP than the unit they thought was transduced; and 53% of residents and 34% of attendings did not know the transduced ICP unit of measure reported in their intensive care unit. CONCLUSIONS: Variability and discrepancies regarding the ICP unit of measure exist in academic neurosurgery departments. Clinicians should familiarize themselves with their hospital's practices. Institutions and all of medicine may consider standardizing the ICP unit of measure, using mmHg as a universal nomenclature.

Spine and spinal cord trauma: diagnosis and management.

Spine trauma is a devastating clinical condition that affects many people annually on a worldwide basis. Management of spinal trauma has become much more surgically oriented with advances in stabilization techniques over the past two decades. The degree of injury to the spinal cord dictates the prognosis of the patient in cervical and thoracolumbar trauma. Traumatic spinal cord injury is a major area of socioeconomic burden and, as such, is a burgeoning area of ongoing research interest.