Relationships between aneurysm initiation and hemodynamic factors remain unclear since de novo aneurysms are rarely observed. Most previous computational fluid dynamics (CFD) studies have used ...artificially reproduced vessel geometries before aneurysm initiation for analysis. In this study, the authors investigated the hemodynamic factors related to aneurysm initiation by using angiographic images in patients with cerebral aneurysms taken before and after an aneurysm formation.
The authors identified 10 cases of de novo aneurysms in patients who underwent follow-up examinations for existing cerebral aneurysms located at a different vessel. The authors then reconstructed the vessel geometry from the images that were taken before aneurysm initiation. In addition, 34 arterial locations without aneurysms were selected as control cases. Hemodynamic parameters acting on the arterial walls were calculated by CFD analysis.
In all de novo cases, the aneurysmal initiation area corresponded to the highest wall shear stress divergence (WSSD point), which indicated that there was a strong tensile force on the arterial wall at the initiation area. The other previously reported parameters did not show such correlations. Additionally, the pressure loss coefficient (PLc) was statistically significantly higher in the de novo cases (p < 0.01). The blood flow impact on the bifurcation apex, or the secondary flow accompanied by vortices, resulted in high tensile forces and high total pressure loss acting on the vessel wall.
Aneurysm initiation may be more likely in an area where both tensile forces acting on the vessel wall and total pressure loss are large.
Background
Severe low back pain (LBP) is an occasional complaint in patients with neuromuscular disorders (NMDs). Accurate diagnosis and treatment are required to manage LBP; however, the precise ...pathophysiology differs for each patient. This study aimed to evaluate the efficacy of lumbar facet joint denervation (FJD) and adjunctive modalities in the treatment of LBP in patients with NMD-associated kyphoscoliosis.
Methods
A total of 16 patients (22 sites) with NMD (bilateral,
n
= 6; unilateral,
n
= 10) and LBP treated with lumbar FJD were evaluated. The patients were divided into two groups: those treated with FJD alone (group 1) and those treated with multimodal treatment, including FJD along with radiofrequency ablation for sacroiliac joint pain, piriform muscle block, botulinum toxin injection into the paraspinal muscles, spinal cord stimulation, or any of their combinations (group 2). All patients were followed up for 48 weeks postoperatively. The two groups were compared with respect to the duration required for improvements in LBP by more than 50% (numerical rating scale ≤ 5).
Results
There was no significant difference between the groups regarding the age, duration since the onset of Parkinson’s syndrome, and radiographic analysis. The effective period of improved pain was greater in group 2 than in group 1 (30.7 vs. 8.4 weeks,
P
< 0.01).
Conclusions
Multimodal treatment including FJD is safe and relatively effective in patients with NMD-associated kyphoscoliosis. Hence, it is a potential substitute for conventional spinal fixation surgery, which has a higher risk of complications.
BACKGROUND AND PURPOSE—Inflammation is a critical determinant of aneurysmal wall destabilization, growth, and rupture risk. Targeting inflammation may suppress aneurysm rupture. Vagus nerve ...stimulation (VNS) has been shown to suppress inflammation both systemically and in the central nervous system. Therefore, we tested the effect of a novel noninvasive transcutaneous VNS approach on aneurysm rupture and outcome in a mouse model of intracranial aneurysm formation with wall inflammation.
METHODS—Aneurysms were induced by a single stereotaxic injection of elastase into the cerebrospinal fluid at the skull base, combined with systemic deoxycorticosterone-salt hypertension, without or with high-salt diet, for mild or severe outcomes, respectively. Cervical VNS (two 2-minute stimulations 5 minutes apart) was delivered once a day starting from the day after elastase injection for the duration of follow-up. Transcutaneous stimulation of the femoral nerve (FNS) served as control. Multiple aneurysms developed in the circle of Willis and its major branches, resulting in spontaneous ruptures and subarachnoid hemorrhage, neurological deficits, and mortality.
RESULTS—In the milder model, VNS significantly reduced aneurysm rupture rate compared with FNS (29% versus 80%, respectively). Subarachnoid hemorrhage grades were also lower in the VNS group. In the more severe model, both VNS and FNS arms developed very high rupture rates (77% and 85%, respectively). However, VNS significantly improved the survival rate compared with FNS after rupture (median survival 13 versus 6 days, respectively), without diminishing the subarachnoid hemorrhage grades. Chronic daily VNS reduced MMP-9 (matrix metalloproteinase-9) expression compared with FNS, providing a potential mechanism of action. As an important control, chronic daily VNS did not alter systemic arterial blood pressure compared with FNS.
CONCLUSIONS—VNS can reduce aneurysm rupture rates and improve the outcome from ruptured aneurysms.
Abstract
BACKGROUND
Thin-walled regions (TWRs) of cerebral aneurysms are at high risk of rupture, and careful attention should be paid during surgical procedures. Despite this, an optimal imaging ...technique to estimate TWRs has not been established. Previously, pressure elevation at TWRs was reported with computational fluid dynamics (CFD) but not fully evaluated.
OBJECTIVE
To investigate the possibility of predicting aneurysmal TWRs at high-pressure areas with CFD.
METHODS
Fifty unruptured middle cerebral artery aneurysms were analyzed. Spatial and temporal maximum pressure (Pmax) areas were determined with a fluid-flow formula under pulsatile blood flow conditions. Intraoperatively, TWRs of aneurysm domes were identified as reddish areas relative to the healthy normal middle cerebral arteries; 5 neurosurgeons evaluated and divided these regions according to Pmax area and TWR correspondence. Pressure difference (PD) was defined as the degree of pressure elevation on the aneurysmal wall at Pmax and was calculated by subtracting the average pressure from the Pmax and dividing by the dynamic pressure at the aneurysm inlet side for normalization.
RESULTS
In 41 of the 50 cases (82.0%), the Pmax areas and TWRs corresponded. PD values were significantly higher in the correspondence group than in the noncorrespondence group (P = .008). A receiver-operating characteristic curve demonstrated that PD accurately predicted TWRs at Pmax areas (area under the curve, 0.764; 95% confidence interval, 0.574-0.955; cutoff value, 0.607; sensitivity, 66.7%; specificity, 82.9%).
CONCLUSION
A high PD may be a key parameter for predicting TWRs in unruptured cerebral aneurysms.
Objective: We report a case of cerebellar infarction caused by radiation-induced common carotid artery stenosis.Case Presentation: The patient was a 72-year-old man who underwent irradiation for ...hypopharyngeal carcinoma 13 years ago. He was referred for asymptomatic left common carotid artery stenosis, but was brought to our hospital by ambulance with transient dysarthria and right facial dysesthesia 2 days after referral. Magnetic resonance imaging (MRI) revealed acute infarction in the left cerebellar hemisphere, and digital subtraction angiography (DSA) demonstrated that the blood flow in the left internal carotid artery perfused the left posterior inferior cerebellar artery (PICA) retrogradely through the left posterior communicating artery. The patient underwent carotid artery stenting (CAS) for left common carotid artery stenosis and blood flow in the left PICA improved; however, in-stent restenosis was revealed during follow-up. Percutaneous transluminal angioplasty (PTA) for in-stent restenosis was performed 9 months after the surgery.Conclusion: We reported a rare case of ischemia in the PICA area caused by radiation-induced common carotid artery stenosis. Although CAS is recommended for the treatment of radiation-induced carotid artery stenosis, careful treatment and follow-up are needed to prevent perioperative complications and detect in-stent restenosis after CAS.
With the increasing demand for rapid diagnosis and treatment of stroke, the telemedicine role of coordinating timely the efforts of the stroke team became important. We developed a system for rapidly ...exchanging diagnostic images and clinical and management information.
A system was created on the basis of communicating patient data and images between hospital systems and participating staff members in and out of the hospital through their standard, currently used handheld communication devices. The system is able to transfer clinical data, CT, MR, angiographic, intraoperative images, and expert opinion in real time.
A pilot application of the system in our hospital showed successful information transfer, allowing medical staff to discuss patients' diagnosis and management using a Twitter system.
The system (i-Stroke) may become a useful tool for acute patient management in the field of neurology and neurosurgery.
Foramen magnum dural arteriovenous fistula (DAVF) is a rare disease, with some reported cases of successful treatment. We achieved complete obliteration of the foramen magnum DAVF through ...microsurgery after complications of endovascular embolization. We reviewed the treatment modalities and outcomes, focusing on pathologic and anatomic features from the literature.
A 65-year-old man was admitted to our hospital with sudden diplopia. Magnetic resonance imaging revealed a subarachnoid hemorrhage around the right side of the prepontine cistern, and a foramen magnum DAVF was diagnosed by angiography. Subsequent angiography revealed that the fistula was supplied by the right neuromeningeal trunk of the ascending pharyngeal artery and the right posterior meningeal artery of the vertebral artery (VA), and the veins of the pouch via the fistula were retrogradely draining into the intracranial veins. We aimed to treat complete occlusion endovascularly with balloon-augmented transarterial Onyx injection via the posterior meningeal artery, but Onyx was refluxed to the VA through the anastomosis between the VA and posterior meningeal artery. Onyx subsequently migrated to the top of the basilar artery, causing occlusion, so we urgently removed the Onyx with a stent retriever (Trevo). Several weeks later, we performed complete obliteration of the foramen magnum DAVF via a lateral suboccipital approach with a C1 laminectomy.
Most foramen magnum DAVFs were obliterated completely with only endovascular treatment. Microsurgery is an effective and reliable treatment for incomplete occlusion and complications.
Intracranial stents are used to treat aneurysms by diverting the blood flow from entering into the aneurysmal dome. Although delayed rupture is rare, clinical outcomes are extremely poor in such ...cases. Hemodynamics after stent deployment may be related to delayed rupture and a better understanding of the basic characteristics of pressure changes resulting from stent deployment is needed; therefore, this study investigated the relationships between hemodynamics in aneurysms of different sizes treated using stents of different wire mesh densities.
Using computational fluid dynamics analysis, parameters related to velocity, volume flow rate, pressure, and residual volume inside the aneurysm were evaluated in digital models of 5 basic aneurysms of differing sizes (Small, Medium, Medium-Large, Large, and Giant) and using 6 different types of stent (varying number of wires, stent pitch and wire mesh density) for each aneurysm.
Regardless of the aneurysm size, the velocity inside the aneurysm and the volume flow rate into the aneurysm were observed to continuously decrease up to 89.2% and 78.1%, respectively, with increasing stent mesh density. In terms of pressure, for giant aneurysms, the pressure on the aneurysmal surface elevated to 10.3%, then decreased to 5.1% with increasing stent mesh density. However, in smaller aneurysms, this pressure continuously decreased with increasing stent mesh density. The flow-diverting effect of the stents was limited when a stent with low mesh density (under 20%) was used with a giant aneurysm.
The present results indicate that the selection of appropriate stents according to aneurysm size may contribute to reduced risks of hemodynamic alternations related to stent deployment, which could reduce the incidence of delayed rupture.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Carpal tunnel syndrome is a common peripheral nerve compression disorder. However, there is no established opinion regarding the predictors of symptom improvement after surgery. This study aimed to ...identify the predictors of surgical outcomes of severe carpal tunnel syndrome patients.
In the patients who underwent a carpal tunnel syndrome surgery, we selected the patients who had a preoperative Bland's classification of grade 5 or 6, and assessed for the changes in Bland's classification grade before and after surgery. Those who showed improvement from preoperative grades 5-6 to postoperative grades 1-4 comprised the improvement group. In contrast, those who did not show improvement and had postoperative grades 5 or 6 comprised the non-improvement group. In a nerve conduction study, amplitudes of the compound muscle action potential and sensory nerve action potential of the palms were assessed between the improvement and non-improvement groups.
Among the 60 hands of 46 patients who had a preoperative Bland's classification of grade 5 or 6, 49 hands of 37 patients comprised the improvement group, and 11 hands of 9 patients comprised the non-improvement group. The amplitudes of the compound muscle action potential and sensory nerve action potential of the palms before surgery were significantly higher in the improvement group. The degree of improvement in Bland's classification grade was correlated with the degree of clinical symptom improvement.
Amplitudes of compound muscle action potential and sensory nerve action potential before surgery induced by palmar stimulation can predict improvements in nerve conduction study scores and clinical findings after surgical treatment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Epidural “blood patch” (EBP) is a standard treatment of spontaneous intracranial hypotension (SIH). In recent years, there are some reports of Racz catheter use for EBP performance at upper cervical ...spine levels. However, the practical use of Racz catheter for single-entry multisite EBP has never been reported until now.
We treated a 60-year-old man diagnosed with SIH presenting with cerebrospinal fluid leaks from the cervical to the sacral segments. We discuss the advantages of the single-entry multisite EBP and the convenience of Racz catheter use in such cases.
The Racz catheter can be a convenient means to deliver large-volume EBPs from a single entry point in the treatment of SIH.
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