Transverse-sigmoid Sinus Research Articles

Morphology and Morphometry of the Asterion in the South African sample within KwaZulu-Natal

IntroductionThe asterion is a meeting point formed by the union of the lambdoid, parieto-mastoid and occipito-mastoid sutures. It is the most common landmark in surgery due to its close relation to the transverse-sigmoid sinus junction. Population-specific differences were noted when determining the position of the asterion using external bony landmarks. Therefore, this study aimed to determine the anatomical position of the asterion in relation to external bony landmarks, and to determine the morphology of the asterion within the South African sample of KwaZulu-Natal. Materials and methodsThirty-six dry adult skulls were obtained from the Department of Clinical Anatomy, University of KwaZulu-Natal. The morphology of the asterion was classified according to Morales Avalos et al. (2011). While, the morphometry regarding the position of the asterion were measured in accordance with Akkaşoğlu et al. (2019) methodology. ResultsType I asterion was observed in 18 (25.0%) of the cases and Type II presented in the majority of the cases with a prevalence of 75.0%. The distances from the asterion to the respective external bony landmarks were found to have no differences with regard to laterality (p > 0.05). The South African sample of KwaZulu-Natal was found to have majority of Type II present. The measurements from the asterion to the external bony landmarks were found to be very similar to an African based population. ConclusionThis study may enhance the existing body of knowledge regarding the morphology and morphometry of the asterion, which may lead to improved outcomes when analysing radiographs and for neuro-surgery.

Dural sinus septum: an underlying cause of cerebral venous sinus stenting failure and complications

ObjectivesThe presence of dural sinus septum has long been identified anatomically but is often neglected for its clinical significance. Our findings revealed the association of dural sinus septum with venous...

Is Asterion a Reliable Surgical Landmark for the Transverse and Sigmoid Sinus Junction in Indian Skulls?

Asterion is the junction of lambdoid, parietomastoid, and occipitomastoid sutures. In traditional anatomy teaching, it is believed that asterion sits over the transverse-sigmoid sinus junction (TSSJ). It is a significant surgical landmark for the placement of a burr hole in the retrosigmoid approach. The purpose of this study was to evaluate the asterion's accuracy as a TSSJ-specific external surgical landmark in the Indian population. 16 human dried skulls were obtained from the Department of Anatomy, AIIMS, New Delhi. The point of TSSJ was taken between the two lips and just posterior to the entry of the superior petrosal sinus. Asterion internally was localized with the help of a geometrical divider. The x- horizontal/ anterior and y- vertically superior (+)/ inferior (-) distances were measured from asterion (internally) to the TSSJ by a digital vernier caliper. The mean horizontal distance (x) of the left side asterion & TSSJ was 10.3±1.0mm whereas the vertical distance (y) ranged between +2 to -4.3 mm. The mean horizontal distance (x) of the right side asterion & TSSJ was 13.5±1.4mm whereas the vertical distance (y) ranged between +3 to -4.2 mm. Asterion is not a reliable landmark for TSSJ in Indian skulls. The TSSJ with respect to asterion was found on average 10mm and 13.5mm anterior on the left and right side respectively, and mostly inferior (average 4.2mm) in 75% of the skulls. The TSSJ was closer to the asterion on the left side in comparison with the right side. However, further studies with a larger sample size will be needed to evaluate the population-specific relation of asterion with the TSSJ.

The Occipitalis Muscle as an Adjunct Superficial Landmark for the Transverse Sinus and Transverse-Sigmoid Junction: An Anatomical Study With Application to Posterior Cranial Fossa Surgery.

Although neuronavigation systems are widely used for identifying deep intracranial structures, additional superficial anatomical landmarks can be useful when this technology is not available or is not working properly. Herein, we investigate the potential of the occipitalis muscle (OM), rarely mentioned in neurosurgical literature, as a superficial landmark for the transverse sinus (TS) and transverse-sigmoid sinus junction (TSJ). Eighteen adult cadaveric heads underwent dissection. The borders of the OM were identified and measured. The muscle was then removed and the bone underlying the muscle was drilled. The relationships between the OM and the underlying dural venous sinuses were then investigated by using a surgical microscope. The OM is a quadrangular-shaped muscle, that invariably crosses the lambdoid suture, showing relationships with the TS inferiorly and the TSJ laterally. The medial border was located a mean of 2.7 cm from the midline and its lower edge was a mean of 1.6 cm above the TS. The inferior border was found between the lambdoid suture and the superior nuchal line in all the specimens. The medial half of the inferior margin was placed on average 1.1 cm superiorly to the TS while the lateral margin ran just above or over the TS. The lateral border was located a mean of 1.1 cm medially to the asterion and approximated the mastoid notch, being within 1-2 cm from it. The TSJ was between 2.1 and 3.4 cm lateral to OM lateral border. A combination of superficial anatomical landmarks can be useful for surgical planning. We found that the OM represents a valuable aide for neurosurgeons and is a reliable landmark for the deeper-lying TS and TSJ.

483 Partial Treatment as a Risk Factor in Up-Conversion of Type 1 dAVFs

INTRODUCTION: Type 1 dural arteriovenous fistulas (dAVFs) lack cortical venous drainage and occasionally necessitate intervention depending on patient symptoms. Up-conversion is the rare transformation of a dAVF to a higher-grade. Causes for up-conversion are unknown. We tested the hypothesis whether partial treatment of type 1 dAVFs increases their likelihood of up-conversion. METHODS: We used the multicenter Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database to perform a retrospective analysis of all patients with type 1 dAVFs. Propensity score analysis was utilized to determine if partial treatment was an independent risk factor for up-conversion. A regression model identified secondary risks that contributed to up-conversion. RESULTS: 358 out of 1077 patients within the consortium had type 1 dAVFs. 12% of patients who were partially treated for a type 1 dAVF experienced an up-conversion, while less than 1% of patients who received no treatment experienced up-conversion, and 0% of patients who had a complete treatment of their dAVF experienced up-conversion. Higher proportions of tinnitus, bruits, and intracranial hemorrhage at initial presentation were found in patients who up-converted. The majority of up-converted dAVFs were located in the transverse-sigmoid sinus and all received embolization as part of their treatment. CONCLUSIONS: Partial treatment is an independent risk factor for up-conversion when compared to no treatment or complete treatment. In the partial treatment group, hemorrhage at inital presentation and use of embolization as a treament modality are factors that increase risk for up-conversion.

Developmental venous anomaly associated with dural arteriovenous fistula: Etiopathogenesis and hemorrhagic risk.

Developmental venous anomalies (DVAs) have traditionally been defined as non-pathological congenital lesions. Compared to isolated DVAs, the association of DVAs with arteriovenous shunts seems to have a more adverse clinical connotation. In this review, we describe the association between DVA and dAVF and discuss the hemorrhagic risk. We also advance a hypothesis about the potential de novo formation of a DVA and challenge the dogma about their "developmental" or "congenital" nature. A systematic review of the literature on the association of DVA and dAVF was performed in accordance with the PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) guidelines. A number of 678 papers was initially identified, but only 9 studies were included in the final qualitative analysis. Most of the patients presented with bleeding (56%), with a median GCS of 14 (range 10-15). In 56% of the cases the DVA had a supratentorial location. Supratentorial DVAs mostly drained in the superior sagittal sinus (80%), while all of infratentorial/combined DVAs drained in deep ependymal veins of the 4th ventricle. All the supratentorial dAVFs drained into the superior sagittal sinus, while the infratentorial/combined dAVFs mostly drained in the jugular bulb, Vein of Rosenthal, or transverse-sigmoid sinuses (75%). Most of the dAVFs were classified as Cognard type IIa + b (67%), while in a smaller number of cases type I (22%) and type V (11%). The dAVF was the target of treatment in each case and most patients underwent endovascular treatment (78%). The dAVF was completely occluded in 78% of cases and no periprocedural complications were reported. The clinical presentation, radiological findings, and treatment outcomes of DVAs and associated dAVFs have been discussed. Despite the general opinion that DVAs are benign congenital lesions, increasing epidemiological and radiological evidence supports a potential acquired origin, and the venous system seem to play a pivotal role in their post-natal genesis and development.

Abstract Number ‐ 73: Successful Endovascular Treatment of Medically Refractory CVST Using a Large Bore Distal Platform Thrombo‐aspiration Catheters.

Introduction Cerebral venous sinus thrombosis (CVST) is a rare (0.5‐2/100,000 incidence) but potentially fatal (5% mortality rate) neurological condition. The diagnosis may be delayed due to the non‐specific presenting symptoms such as headache, altered mental status, or seizures. Anticoagulation has long been the standard therapy for CVST. However, a subset of patients do not respond to medical therapy, and may develop complications such as ischemic stroke, hemorrhage, and cerebral edema. In the ISCVT study, 13% of patients experienced poor outcomes despite anticoagulation. Recently, it has been shown that patients with extensive clot burden, cerebral edema, elevated ICP, and altered mentation may achieve better outcomes with endovascular thrombectomy (EVT) compared to anticoagulation. We present a patient with CVST who failed therapeutic anticoagulation but improved with thrombectomy using the novel Zoom 088 Aspiration system, that further demonstrating the efficacy of combination therapy with anticoagulation and EVT. Methods A case report of successful CVST treatment using large bore aspiration catheters. Results A 37‐year‐old woman with a history of migraine and current oral contraceptive use presented with acute, persistent, and severe right hemicranial and retro‐orbital headache. Non‐contrast CT head suggested thrombosis of the right transverse sinus. MR venogram confirmed CVST involving the right transverse sinus, sigmoid sinus, and internal jugular vein. We started therapeutic anticoagulation, but the patient’s headache progressively worsened. Repeat MR venogram revealed extension of the CVST. Given clinical and radiological worsening, we proceeded with EVT procedure using a Zoom 088 aspiration system, resulting in successful recanalization of the involved sinuses. However, there was persistent severe headache following the procedure. She developed a new long segment obstructive thrombus in the left transverse sinus and partial re‐occlusion of the right sigmoid sinus on repeat MR venogram. A second EVT procedure was performed using the Zoom 088 Aspiration system, with complete recanalization. Postoperatively, her symptoms resolved and at 3‐month follow‐up she remained largely asymptomatic without neurological deficits. To the best of our knowledge, this is the first reported successful clinical use of the Zoom 088 aspiration device for CVST. The Zoom 088 Aspiration system is a newer generation large distal platform thrombo‐aspiration catheter. Studies have established efficacy of contact aspiration and stent retriever technique for arterial thrombi. Venous sinus clots are loosely bound to the vessel wall, perhaps making them more readily removable through aspiration. However, its standard application for CVST, including its efficacy and complication rates, remain to be analyzed in larger prospective studies. Conclusions This case highlights the pivotal role of EVT, especially large‐bore catheter based aspiration approach, in the management of medically refractory CVST. Thrombo‐aspiration technology is evolving at an accelerated rate with versatile and navigable devices such as the Zoom 088 aspirator. Larger studies are warranted to establish its technical efficacy and safety profile.

Letter: Angioarchitectural Analysis of Arteriovenous Shunts in Dural Arteriovenous Fistulas and Its Clinical Implications.

To the Editor: We were intrigued to read the recently published article by Junhyung Kim et al titled “Angioarchitectural Analysis of Arteriovenous Shunts in Dural Arteriovenous Fistulas and Its Clinical Implications.”1 The authors proposed a classification for 4 shunt patterns of dural arteriovenous fistulas (DAVFs) based on the fistula, sinus, and cortical vein connection in the transverse-sigmoid sinus and superior sagittal sinus region: direct sinus fistula, compartmental sinus channel, mural channel, and bridging vein shunt. Different treatment strategies may be performed for various shunt patterns. The authors referred to fistulas that entered the sinus directly from feeding arteries as “direct sinus fistulas.” The “compartmental sinus channels” were identified by arterial feeders converging into a partially thrombosed sinus or a separate sinus channel. Mural channels were outlined as tubular elements that were cut off from the sinus main lumen. Bridge vein shunts were defined as fistulas formed where bridging veins and sinuses meet.1 They also summarized some conclusions, such as the mural channel was directly connected to the cortical vein, which has important therapeutic implications. Following the author's research, readers will gain a better understanding of the angioarchitecture of DAVFs around the sinus region. However, our clinical experience and literature review lead us to believe that the fistulas are not directly at the sinus.2,3 Before the sinus or cortical veins drainage, blood must first travel through the dural veins from the dural arteries and then to the sinuses or bridging veins. A very long or very short segment of the draining dural vein is possible. A dural vein is frequently mistaken for a supplying artery when it is very long. In a number of cases at our center, despite the lack of histopathological examinations, we can identify that the supplying arteries and the draining dural veins are completely different. Arteries branch and taper, and veins receive branches and gradually thicken their lumens. After the selection of feeding arteries and straining veins, the sites at which the calibers between them change from thin to thick are regarded the location of fistulas. The draining dural veins and location of fistulas are also an essential part of angioarchitecture. This understanding of angioarchitecture enables the super-selection of the draining dural veins and the blocking of the drainage veins by transarterial or transvenous embolization to treat DAVF while maintaining the patency of the drainage venous sinus. The authors of this article defined the feeding arteries directly into the sinus or the junction of the bridging veins and sinuses, which, like many other articles, is incorrect. DAVFs in transverse-sigmoid sinus and superior sagittal sinus are sometimes with pial arterial supply.4 Although the authors did not focus on describing feeding arteries, they are an important component of angioarchitecture. When dealing with DAVFs with pial arterial supplies, the treatment strategy will be different. The angioarchitecture of DAVF is so complex and variable that it can be difficult to fully understand without histopathological analyses. We appreciate the authors for introducing novel ideas to the readers.

In Reply: Angioarchitectural Analysis of Arteriovenous Shunts in Dural Arteriovenous Fistulas and Its Clinical Implications.

To the Editor: We would like to thank Dr Su et al1 for sharing their insights on dural arteriovenous fistulas (DAVFs) and thoughtful and duly comments on our recent article “Angioarchitectural analysis of arteriovenous shunts in dural arteriovenous fistulas and its clinical implications.”2 Based on the histopathological studies and their experience of DAVFs, Dr Su et al point out that fistulas are not formed directly at the dural sinuses but between the dural artery and the dural vein (in the dural sinus wall) before draining into the sinus or the bridging vein.1,3,4 We agree with these classic histopathological finding; however, the main focus of our study was to describe and discriminate the “angiographic” shunt patterns in light of the connections between the shunt, the sinus, and the cortical veins to unveil their practical implications. In this regard, there were specific patients in whom the targetable fistulous channel—regarding the branching patterns and the caliber changes of the vessels—could not be identified but showed functionally direct connections with the sinus. The histopathological basis for these kinds of shunt remains speculative. The variations in the anatomy of the dural vessels (length, location, etc), secondary changes associated with venous hypertension, thrombosis, inflammation, angiogenesis, and dural wall alterations alongside the temporal changes may have manifested as this pattern.3-8 Interestingly in our series, multiple shunt types were noted in several patients (n = 7), more frequently as the coexistence of the direct sinus fistulae and mural channel-type shunts (n = 5), suggesting the dynamic nature of this disease. Extensive histopathological studies are crucial to shed light on these compelling questions but are extremely limited. Meanwhile, angiographic discrimination of the different characteristics of the shunts, such as the diffuse direct connections or channel-like structures or bridging vein type shunts, and their connection patterns with the sinus and the cortical vein are paramount for effectively targeting the lesion and predicting the behavior of the liquid embolic agents. The presence of pial arterial supply to the DAVF has gained much interest. There are concerns that these patients may be associated with postprocedural rupture of the fragile neovascularized vessels after venous outflow obstruction and inadvertent reflux of the embolic agent into the pial arteries.9,10 The presence of the pial feeders are known to be strongly associated with the tentorial DAVFs.9,10 Our series included only the superior sagittal and transverse sigmoid sinus DAVFs; thus, analyzing the implications of pial supplies was considered beyond the scope of our study. However, this is an interesting topic that deserves further scrutinization. We greatly appreciate the comments and insights by Dr Su et al. DAVFs are fascinating but also complex and challenging diseases. We wish for further technological progress and the power of collective intelligence in understanding and overcoming this intriguing disease.

Diagnosis and treatment of otogenic sigmoid sinus thrombophlebitis

Objective:To summarize and analyze the clinical data of sigmoid sinus thrombophlebitis and discuss its treatment strategy. Methods:The clinical manifestations, auxiliary examinations, surgical procedures and anticoagulant therapy of patients diagnosed with otosource sigmoid sinus thrombophlebitis in the Department of Otorhinolaryngology, People's Hospital of Xinjiang Uygur Autonomous Region from November 2014 to November 2021 were retrospectively analyzed. Results:Five patients had a history of otorrhea and hearing loss for more than 5 years. They had headache during the acute episode, and 4 patients had drosive fever. They had severe complications, including brain abscess, sepsis, septic shock, intracranial hemorrhage, and hemorrhagic disseminated pneumonia. HRCT of temporal bone showed defects in the sigmoid sinus wall in 4 cases, and gas accumulation around and inside the sigmoid sinus in 3 cases. T1WI showed low signal, isosignal, and high signal in the sigmoid sinus area on MRI, and T2WI showed high signal in the sigmoid sinus area. The transverse sinus, sigmoid sinus and internal jugular vein were not developed in 2 cases, and the transverse sinus and sigmoid sinus were not developed in 1 case, and the internal jugular vein was thin. All 5 cases underwent radical mastoidectomy and resection of sigmoid sinus wall granulation or peritosinusitis abscess. The patients were followed up for 4-12 months and recovered well. Conclusion:For the cases of sigmoid sinus bone wall destruction accompanied by headache and fever by HRCT, it is necessary to be alert to the occurrence of sigmoid sinus thrombophlegitis, early diagnosis and early surgery to prevent the progression of the disease. Radical mastoidectomy combined with anti-infection therapy is the main treatment, and anticoagulation is necessary to achieve a better prognosis.

Analysis of Etiology, Diagnosis, and Treatment Strategy and Efficacy of Pulsatile Tinnitus Caused by Abnormal Vascular Anatomy.

To investigate the etiology, clinical characteristics, diagnosis, and treatment strategies and efficacy of pulsatile tinnitus (PT) caused by vascular anatomy abnormality. The clinical data of 45 patients with PT in our hospital from 2012 to 2019 were collected and retrospectively analyzed. All 45 patients had vascular anatomical abnormalities. The patients were divided into 10 categories according to the different locations of vascular abnormalities: sigmoid sinus diverticulum (SSD), sigmoid sinus wall dehiscence (SSWD), SSWD with high jugular bulb, pure dilated mastoid emissary vein, aberrant internal carotid artery (ICA) in the middle ear, transverse-sigmoid sinus (TSS) transition stenosis, TSS transition stenosis with SSD, persistent occipital sinus stenosis, petrous segment stenosis of ICA, and dural arteriovenous fistula. All patients complained of PT synchronous with heartbeat rhythm. Endovascular interventional therapy and extravascular open surgery were used according to the location of the vascular lesions. Tinnitus disappeared in 41 patients, was significantly relieved in 3 patients, and was unchanged in 1 patient postoperatively. Except for one patient with transient headache postoperatively, no obvious complications occurred. PT caused by vascular anatomy abnormalities can be identified by detailed medical history and physical and imaging examination. PT can be relieved or even completely alleviated after appropriate surgical treatments.

Application of Preoperative Multimodal Image Fusion Technique in Microvascular Decompression Surgery via Suboccipital Retrosigmoid Approach

To explore the application value of preoperative multimodal image fusion technique in microvascular decompression (MVD) surgery via the suboccipital retrosigmoid approach. Comprehensive data of 13 patients with primary trigeminal neuralgia (TN) and 13 patients with hemifacial spasm (HFS) treated by MVD surgery via the suboccipital retrosigmoid approach at the Department of Neurosurgery in Zhuhai People's Hospital from January 2021 to December 2021 were retrospectively analyzed. Preoperatively, all patients underwent cranial thin-section computed tomography and magnetic resonance examinations. Three-dimensional (3D) digital images of the skull, brainstem, nerves, and blood vessels were constructed by the 3D-slicer software or RadiAnt DICOM Viewer, which were then applied to design the surgical approach and surgical plan. The multimodal image fusion results, clinical characteristics, intraoperative data, surgical outcomes, and complications of all patients were summarized. The 3D digital images after fusion reconstruction can vividly show the anatomical relationship between the skull, brainstem, nerves, and blood vessels and was helpful to tailor the surgical strategy. All 26 patients underwent a smooth surgery. During the surgery, the key points were accurately located, the corners of the transverse sinus and sigmoid sinus were completely exposed, and no venous sinus injury occurred in all 26 patients. The key point was approximately located at the top point of the digastric groove, 12.3±0.46mm vertically above and 6.3±0.6mm laterally to the Frankfurt horizontal plane. The average cranial opening time was 30.4 (±3.6) min, and the mean operating time was 104.7 (±12.1) min. The diameter of the bone window was about 2.0 cm-3.0cm, and the bone flap was restored. Among the 13 patients with primary TN, 12 (92.3%) exhibited complete relief of pain and 1 had significant relief. Complications of surgery included facial sensory numbness in 1 case, vertigo in 2 cases, and herpes at the corners of the mouth in 1 case. Of the 13 patients with HFS, 12 (92.3%) had complete relief of facial twitching symptoms and 1 had significant relief, and the complications included mild facial palsy in 2 (15.4%) cases and facial sensory numbness in another 2 (15.4%) cases. The mean follow-up time after surgery ranged from 6-16months, and 1 of 26 patients experienced recurrence of HFS during the follow-up period. Preoperative multimodal image fusion technology can provide adequate preoperative assessment for patients and assistance in designing surgical approaches, which is an important guideline for MVD surgery via the suboccipital retrosigmoid approach for primary TN and facial muscle spasm.

Influence of sigmoid plate and dura mater on vascular wall displacement, vibroacoustic/hydroacoustic sources characteristics, and frequency-loudness assessments of venous pulsatile tinnitus: A coupled-computational fluid dynamics study combining transcanal recording investigation

Investigations of pulsatile tinnitus (PT) caused by sigmoid sinus wall anomalies (SSWAs) using computational fluid dynamics (CFD) have recently increased in prevalence. However, accurate modeling of anatomical structures regarding sigmoid plate dehiscence and acoustic sources of PT remains lacking. This study incorporates coupled CFD techniques, micro-computed tomography, and scanning electron microscope to reveal the vibroacoustic and hydroacoustic sources and displacement characteristics of the transverse-sigmoid sinus system. Furthermore, the in vivo transcanal-recording technique combined with ipsilateral internal jugular vein compression was implemented to cross-reference the captured acoustic profile of PT with the calculated results. In this study, the transient state coupled CFD technique was used to calculate the vibroacoustic and hydroacoustic sources. The dehiscent sigmoid plate and periosteal dura mater were then reconstructed. The displacement characteristics and acoustic results were analyzed. The displacement of the vascular wall underneath the dehiscent area was 9.6 times larger than that of the sigmoid plate and 3,617 times smaller than that of the vascular wall without the overlying osseous structures. The peak amplitude of flow-induced vibroacoustic noise was 119.3dB at 20.2Hz measured at the transverse sinus. Within the observed 20-1,000Hz frequency range, the largest peak amplitude of hydroacoustic noise was 80.0dB at 20.2Hz located at the jugular bulb region. The simulated results conformed with the in vivo acoustic profile which the major frequency of PT falls within 1,000Hz. In conclusion, 1) the sigmoid plate and dura mater greatly impact vascular wall displacement, which should not be overlooked in CFD simulations. 2) By incorporating the transcanal recording technique with IJV compression test, the primary frequency of PT was found fluctuating below 1,000Hz, which matches the frequency component simulated by the current CFD technique; amplitude-wise, however, the peak amplitude of in vivo pulse-synchronous somatosound measures approximately 10dB, which is comparatively lesser than the CFD results and the subjectively perceived loudness of PT. Thus, the transmission pathway, intramastoid acoustic impedance/amplification effect, and the perceptive threshold of PT require further investigations to minimize the incidence of surgical failure.

Flow patterns in the venous sinus of pulsatile tinnitus patients with transverse sinus stenosis and underlying vortical flow as a causative factor

BackgroundTransverse sinus stenosis (TSS) is commonly found in Pulsatile Tinnitus (PT) patients. Vortex flow is prominent in venous sinus with stenosis, and so it is important to determine the distribution and strength of the vortical flow to understand its influence on the occurrence of PT. MethodsIn this study, by using computational fluid dynamics for hemodynamic analysis in patient-specific geometries based on Magnetic Resonance Imaging (MRI), we have investigated the blood flow within the venous sinus of 16 subjects with PT. We have employed both laminar and turbulent flow models for simulations, to obtain (i) streamlines of velocity distribution in the venous sinus, and (ii) pressure distributions of flow patterns in the venous sinus. Then, hemodynamic analysis in the venous sinus recirculation zone was carried out, to determine the flow patterns at the junction of transverse sinuses and sigmoid sinuses. Finally, we have proposed a new model for turbulence evaluation based on the regression analysis of anatomic and hemodynamics parameters. ResultsCorrelation analysis between the anatomical parameters and the hemodynamic parameters has shown that stenosis at the transverse sinus was the main factor in the local hemodynamics variation in the venous sinus of patients; in this context, it is shown that vorticity can be used as a prime indicator of the severity of the stenosis function. Our results have shown a significant correlation between the vorticity and the stenotic maximum velocity (SMV) (r = 0.282, p = 0.004). Then, a parameterized prediction model is proposed to determine the vorticity in terms of flow and anatomic variables, termed as the turbulence eddy prediction model (TEP model). Our result have shown that the TEP model is sensitive to the dominant flow distribution, with a high correlation to the flow-based vorticity (r = 0.809, p = 0.009). ConclusionsThe quantification of the vorticity (as both vorticity and MVV) in the downstream of TSS could be a marker for indication of turbulent energy at the transverse-sigmoid sinus, which could potentially serve as a hemodynamic marker for the functional assessment of the PT-related TSS.

Clinical Characteristics and Prognostic Factors of Non-Infectious Cerebral Venous Sinus Thrombosis.

Non-infectious cerebral venous thrombosis (CVT) is an uncommon type of cerebrovascular disease that usually affects young patients. It occurs frequently in female patients, probably due to the association of sex-specific risk factors for coagulopathies. Currently, the prognostic factors of CVT remain unclear. We retrospectively reviewed the clinical characteristics among 260 CVT patients, including 147 females and 113 males. A favorable clinical outcome was defined by the scores of the modified Rankin Scale (mRS) ≤ 2 at hospital discharge, while a poor clinical outcome was defined by an mRS score of 3 to 6. A headache (28.5%) was the most frequent presentation. The most commonly affected sinus was the transverse-sigmoid sinus (59.6%). Most of the cases (78.5%) were treated with anticoagulants. One hundred and fifty-seven patients (60.4%) were discharged with favorable clinical outcomes. Consciousness disturbance (odds ratio: 5.01, p < 0.001) was associated with a poor clinical outcome. Patients with poor clinical outcomes demonstrated higher D-dimer levels on admission (4137.76 ± 3317.07 vs. 2476.74 ± 2330.87 ng/mL FEU, p = 0.029) and longer hospitalization days (31.81 ± 26.29 vs. 13.96 ± 8.82 days, p < 0.001) compared with favorable clinical outcomes. These findings provide important information of clinical characteristics and prognosis for CVT. Aggressive monitoring and treatment should be considered in CVT patients with poor prognostic factors.

A New Practical Method Based on MRI to Individually Localize the Transverse-Sigmoid Sinus Junction in Retrosigmoid Craniotomy: A Retrospective Before-After Study.

Although the asterion has long been used as a skeletal surface marker of the transverse-sigmoid sinuses junction (TSSJ) point in the retrosigmoid approach, abundant evidence shows that the relationship between asterion and TSSJ point varies greatly. In recent years, new technologies have been developed, such as neuronavigation and three-dimensional volume rendering imaging, that can guide in exposing the TSSJ point individually. However, they are not only expensive but also difficult to apply in emergency surgery. To introduce a quick, practical, and low-cost new method for locating the TSSJ point precisely. In this retrospective before-after study, the test group located the TSSJ point with our new method during a 6-month period, while the control group used asterion as a surface landmark to estimate the TSSJ during the preceding 6 months. The primary outcome is the immediate exposure rate of the TSSJ point by the initial burr hole. There were 60 patients in both control and test groups as no significant difference in the general clinical characteristics of both groups were observed. The new three-step method significantly increased the TSSJ exposure rate by initial burr hole compared with the control group (96.67% vs. 53.33%, P = 0.0002). Moreover, the total bone loss and craniotomy duration were significantly reduced by the new method. Incidence of sinus injury (10% vs. 6.6%), post-operation infection (3.33% vs. 3.33%), and CSF leakage (3.33% vs. 0%) were similar. The novel three-step approach accurately locates TSSJ points in retrosigmoid craniotomy, reduces bone defects, saves time, and does not increase the risk of sinus injury, infection, and CSF leakage.

Angioarchitectural Analysis of Arteriovenous Shunts in Dural Arteriovenous Fistulas and Its Clinical Implications.

Detailed understanding of the angioarchitecture of arteriovenous shunts in dural arteriovenous fistulas (DAVFs) is essential when planning endovascular treatment. To analyze shunt patterns and their clinical implications in transverse-sigmoid sinus and superior sagittal sinus DAVFs. A total of 48 DAVFs treated with endovascular embolization between January 2010 and June 2021 were investigated. The preprocedural and intraprocedural digital subtraction angiograms were examined to characterize the shunt patterns of DAVFs in terms of anatomic relations to the sinuses and cortical veins. Treatment characteristics and outcomes were evaluated. The shunt patterns were categorized into 4 types: the direct sinus fistula (n = 8/48, 16.7%), compartmental sinus channel (n = 14/48, 29.1%), mural channel (n = 13/48, 27.1%), and bridging vein shunt (n = 13/48, 27.1%). Mural channel lesions revealed direct (n = 4/13, 30.8%) and indirect (n = 6/13, 46.2%) cortical venous connections. Multiple shunt types were seen in 7 patients. Overall, complete or near-complete occlusion was achieved in 43 patients (89.6%) after the final embolization. Patients with mural channels received the most embolization sessions (1.4 sessions per patient). Procedural venous drainage-related complications occurred in patients with multiple shunt types including mural channel shunts (n = 3). All bridging vein shunts were completely occluded during a single transarterial embolization session. The 4 shunt patterns of DAVFs demonstrate distinct characteristics for the fistula, sinus and cortical vein connection. Meticulous analysis of the angioarchitectural characteristics and clinical implications is warranted for safe and effective treatment.

Cerebral venous sinus thrombosis in a patient with Klebsiella pneumoniae primary liver abscess: a case report

BackgroundLiver abscess is a common emergency in the emergency department. However, cerebral venous sinus thrombosis (CVST) is a rare and serious cerebrovascular disease. Cases of CVST in patients with Klebsiella pneumoniae primary liver abscess (KLA) have not been described in the literature. We report a case of CVST in patients with KLA.Case presentationA 54-year-old male patient came to our department with a fever for 2 days and altered mental status for 1 day. Abdominal computed tomography (CT) and liver magnetic resonance imaging (MRI) revealed multiple liver abscesses. The blood culture was identified as Klebsiella pneumoniae sepsis. Head contrast-enhanced MRI and magnetic resonance venography (MRV) imaging showed multiple thrombus formation in the right transverse sinus and sigmoid sinus. The patient's infection and thrombosis were controlled within one week of multidisciplinary comprehensive treatment such as antibiotic and antithrombotic therapy, and a good clinical recovery during the 1-month follow-up.ConclusionCVST after liver abscess is rare, clinicians should be aware of this complication and vigilant for the possibility of bacterial meningitis. The underlying mechanisms need to be further studied.

Analysis of Revision Surgery Following Surgical Reconstruction of the Sigmoid Sinus Wall in Patients with Pulsatile Tinnitus.

Background:To explore potential causes leading to the failure of the surgical reconstruction of sigmoid sinus wall in patients with pulsatile tinnitus.Methods:This study retrospectively analyzed pulsatile tinnitus patients with sigmoid sinus wall dehiscence and/or sigmoid sinus diverticulum, who underwent revision surgeries following the surgical reconstruction of the sigmoid sinus wall.Results:A total of 7 pulsatile tinnitus patients were included. After the first surgery, 5 of 7 patients showed varying degrees of remission in pulsatile tinnitus, but pulsatile tinnitus gradually recurred. The other 2 patients experienced no change in pulsatile tinnitus. Images after the first surgeries revealed that the surgical failure of Patients 1-5 was caused by incompleted elimination of sigmoid sinus wall dehiscence and sigmoid sinus diverticulum. Following revision surgeries, they all acquired great or complete resolution of pulsatile tinnitus. In Patient 6, an abnormal diploic vein entering the sigmoid sinus was overlooked during the first surgery for repairing sigmoid sinus wall dehiscence. As soon as the diploic vein was blocked during the revision surgery, the patient’s pulsatile tinnitus was alleviated significantly. Patient 7 had a recurrence of pulsatile tinnitus after transient improvement following the first surgery, and still experienced no change in pulsatile tinnitus after the revision surgery. However, after venous sinus stenting in the stenosis of transverse-sigmoid sinus junction, she got complete resolution of pulsatile tinnitus. It suggested that the unresolved stenosis of the venous sinus was the cause of the surgical failure.Conclusions:Both sigmoid sinus diverticulum and sigmoid sinus wall dehiscence are recommended to be resolved during surgery. Abnormal diploic veins and venous sinus stenosis are potential causes of pulsatile tinnitus.

Lariboisiere Hospital pre-operative surgical checklist to improve safety during transpetrosal approaches.

Transpetrosal approaches are technically complex and require a complete understanding of surgical and radiological anatomy. A careful evaluation of pre-operative magnetic resonance imaging and computed tomography scan is mandatory, because anatomical or pathological variations are common and may increase the risk of complications related with the approach. Pre-operative characteristics of venous and petrous bone anatomy were analysed and correlated with intraoperative findings, using injected magnetic resonance imaging and thin-slices computed tomography scan. These data regularly checked before each transpetrosal approach were progressively included in the presented checklist. Transpetrosal approaches have been used in 101 patients. Items included in the checklist were petrous bone pneumatization, angle between petrous apex and clivus, dehiscence of petrous carotid artery, dehiscence of geniculate ganglion, distance between superior semicircular canal and middle fossa floor, distance between cochlea and middle fossa floor, sigmoid sinus dominance, transverse sigmoid sinus junction depth to the outer cortical bone, jugular bulb height (high or low), location of the vein of Labbé, characteristics of superior petrosal vein complex. The presented checklist provides a systematic scheme of consultation of characteristic of venous and petrous bone anatomy for transpetrosal approaches. In our experience, the use of this checklist reduces the risk of complications related with approach, by minimizing the neglect of crucial information.