Acta Neurochirurgica最新文献

Background

Wall shear stress (WSS) plays a crucial role in the natural history of intracranial aneurysms (IA). However, spatial variations among WSS have rarely been utilized to correlate with IAs’ natural history. This study aims to establish the feasibility of using spatial patterns of WSS data to predict IAs’ rupture status (i.e., ruptured versus unruptured).

Methods

“Patient-specific” computational fluid dynamics (CFD) simulations were performed for 112 IAs; each IA’s rupture status was known from medical records. Recall that CFD-simulated hemodynamics data (wall shear stress and its derivatives) are located on unstructured meshes. Hence, we mapped WSS data from an unstructured grid onto a unit disk (i.e., a uniformly sampled polar coordinate system); data in a uniformly sampled polar system is equivalent to image data. Mapped WSS data (onto the unit disk) were readily available for Radiomics analysis to extract spatial patterns of WSS data. We named this innovative technology “WSS-informatics” (i.e., using informatics techniques to analyze WSS data); the usefulness of WSS-informatics was demonstrated during the predictive modeling of IAs’ rupture status.

Results

None of the conventional WSS parameters correlated to IAs’ rupture status. However, WSS-informatics metrics were discriminative (p-value < 0.05) to IAs’ rupture status. Furthermore, predictive models with WSS-informatics features could significantly improve the prediction performance (area under the receiver operating characteristic curve [AUROC]: 0.78 vs. 0.85; p-value < 0.01).

Conclusion

The proposed innovations enabled the first study to use spatial patterns of WSS data to improve the predictive modeling of IAs’ rupture status.

Objective

To explore the correlation between posterior fossa crowding and the occurrence of classical trigeminal neuralgia (TN).

Methods

A total of 60 patients diagnosed with classical TN and 60 age- and sex-matched healthy volunteers were included as a control group for a case-control study. All subjects underwent high-resolution 3D magnetic resonance imaging (MRI) examinations (including 3D-FIESTA and 3D-TOF MRA sequences). The original data were subjected to 3D reconstruction and measurement of posterior fossa volume (PFV) and hindbrain volume (HBV) using 3D-slicer software. The posterior fossa crowding index (PFCI) was calculated as HBV/PFV × 100%. Finally, data were analyzed using SPSS 22.0 statistical software.

Results

The average PFCI in patients with TN was 85.0% ± 3.9%, compared to 82.7% ± 3.9% in the control group, with a significant statistical difference (P = 0.025). Female patients with TN had a more crowded posterior fossa than male patients (86.4% ± 3.8% vs. 83.4% ± 3.4%, P = 0.033). Multiple linear regression analysis showed that a higher PFCI was associated with being female (P = 0.022), younger age (P = − 0.003), and being a patient with TN (P = − 0.023).

Conclusion

Patients with PTN have a more crowded posterior fossa compared to the healthy control group. A higher PFCI is associated with being female, younger age, and being a patient with TN. Posterior fossa crowding may be a risk factor for neurovascular conflict (NVC), making it more likely to lead to the occurrence of TN.

Background

Intraoperative ultrasound is becoming a common tool in neurosurgery. However, effective simulation methods are limited. Current, commercial, and homemade phantoms lack replication of anatomical correctness and texture complexity of brain and tumour tissue in ultrasound images.

Methods

We utilise ex-vivo brain tissue, as opposed to synthetic materials, to achieve realistic echogenic complexity and anatomical correctness. Agar, at 10–20% concentrate, is injected into brain tissue to simulate the tumour mass. A commercially available phantom was purchased for benchmarking.

Results

Qualitative analysis is performed by experienced professionals, measuring the impact of the addition of agar and comparing it to the commercial phantom. Overall, the use of ex vivo tissue was deemed more accurate and representative, compared to the synthetic materials-based phantom, as it provided good visualisation of real brain anatomy and good contrast within tissue. The agar tumour correctly produced a region of higher echogenicity with slight diffusion along the margin and expected interaction with the neighbouring anatomy.

Conclusion

The proposed method for creating tumour-mimicking tissue in brain tissue is inexpensive, accurate, and simple. Beneficial for both the trainee clinician and the researcher. A total of 576 annotated images are made publicly available upon request.

Purpose

It was noticed that anterior choroidal artery (AChoA) aneurysms appear to rupture at relatively smaller sizes compared with aneurysms in other intracranial locations, based on anecdotal clinical experience. We therefore aimed to compare ruptured AChoA aneurysms with other ruptured aneurysms in other intracranial locations, pertaining to aneurysm dimensions. This may help in finding out if the rupture risk stratification, based on the amalgamation of aneurysms of multiple locations in one group, precisely estimates aneurysm rupture risk.

Methods

255 ruptured intracranial aneurysms, which underwent assessment with catheter angiography with 3D reconstruction, in a single tertiary center between January 2000 and December 2023, were included. 6 aneurysm dimensions were compared.

Results

Statistically significant larger aneurysm maximum diameter, height, width and size ratio (SR) of the ruptured posterior communicating artery (PCOMM) aneurysms were identified when compared with ruptured AChoA aneurysms.

No statistically significant difference in the aneurysm maximum diameter, height and width between the ruptured AChoA and ruptured anterior cerebral artery (ACA), anterior communicating artery (Acom), pericallosal artery and basilar tip aneurysms was found.

AChoA aneurysms appear to rupture at a relatively small size, which is comparable to other aneurysm locations that are often grouped into different categories in rupture risk stratification.

Conclusion

More detailed location-specific rupture risk estimation may be needed. The combination of multiple intracranial aneurysm locations into a single category for risk stratification may not reflect the true aneurysm size at rupture for some aneurysms.

Background

Reaching parenchymal segments of the lateral lenticulostriate artery (LSA) perforators, which represent the medial resection limit in insular gliomas (IG), remains a challenge. The currently described methods are indirect and sometimes, imprecise.

Methods

We report an antegrade direct skeletonization technique to identify these tiny arteries at the medial end of IGs with an illustrative case of grade 2 astrocytoma. The patient recovered uneventfully following a near total tumor resection without any postoperative radiological ischemia in the LSA territory.

Conclusions

Our microsurgical technique of antegrade LSA skeletonization may be useful in insular gliomas with a sharp medial border.

A 54-year-old man presented with gait disturbances, urinary incontinence, and headache for 6 months. Head computed tomography indicated several high-density mass lesions in the quadrigeminal cistern, causing occlusive hydrocephalus. Digital subtraction angiography confirmed tentorial dural arteriovenous fistulae (AVF). Transarterial embolization (TAE) achieved complete angiographic resolution. However, acute occlusive hydrocephalus worsened, necessitating endoscopic third ventriculostomy (ETV). The patient was discharged without new symptoms and no hydrocephalus recurrence at six-month follow-up. Hydrocephalus is rare in patients with dural AVF and mostly resolves spontaneously after treatment; however, if thrombosis and enlargement of the varix occur after treatment, acute occlusive hydrocephalus can develop.

Background

The Focused Sylvian Approach (FSA) is a refined, minimally invasive technique for clipping small to medium-sized middle cerebral artery (MCA) aneurysms, prioritizing safety and aesthetics.

Method

The craniotomy remains confined to the superior temporal line, with the incision concealed within the temporal muscle. The Sylvian fissure is carefully dissected to preserve venous structures.

Conclusion

FSA achieves optimal vascular control with superior cosmetic outcomes while maintaining adequate exposure for safe aneurysm clipping.

Background

Variability in long-term endovascular treatment outcomes for intracranial aneurysms has prompted questions regarding the effects of these treatments on aneurysm hemodynamics. Endovascular techniques disrupt aneurysmal blood flow and shear, but their influence on intra-aneurysmal pressure remains unclear. A better understanding of aneurysm pressure effects may aid in predicting outcomes and guiding treatment decisions.

Methods

Medium and large aneurysm models with intramural pressure taps on the dome and parent artery were designed and 3D-printed with vessel-like physical properties from UV-cured materials. The models were connected to a comprehensive flow system consisting of a pulsatile pump and a viscosity-matched blood analog. The system provided physiological pressure and flow control. Real-time pressures were recorded in the aneurysm dome and parent artery during initial placement of coils, stents, flow diverters, and temporary balloons under simulated surgical conditions. Coiling, stent-assisted coiling, and flow diverter placement were performed in both aneurysm sizes. Temporary balloon placement was performed in a large aneurysm model.

Results

Coiling resulted in 24–30% packing density and diminished intra-aneurysmal flow. Flow diverter placement reduced intra-aneurysmal flow with near complete flow interruption after placement of three consecutive devices across the aneurysm neck. Compared to untreated controls, real-time pressure measurements during coiling and flow diversion showed minimal changes (< 5%) in intra-aneurysmal pressures. Temporary balloon occlusion blocked the parent artery, increasing the pressure proximal to the site of occlusion (by 9%), and reducing the pressure distally (by 14%). This maneuver also dampened intra-aneurysmal pressure to the average distal vessel pressure measurement. Positive control aneurysm models were 3D-printed with a sealed, “healed” neck. These controls verified a sealed neck eliminates intra-aneurysmal pressure.

Conclusion

Findings quantified minimal changes in intra-aneurysmal pressure during and immediately post-coiling and flow diversion. Intra-aneurysmal flow disruption alone has negligible impact on intra-aneurysmal pressures.

Purpose

Bypass surgery is regarded as the standard treatment option for symptomatic and hemodynamically unstable moyamoya disease (MMD). However, there is ongoing debate about the most effective type of bypass surgery. We aimed to analyze the long-term outcomes of combined and indirect bypasses for MMD patients through intra-individual comparisons.

Methods

Of the 896 patients who underwent 1084 bypass surgeries between 2007 and 2021, 24 patients with MMD who underwent combined bypass on one side and indirect bypass on the other side were ultimately enrolled in this study. Clinical, angiographic and hemodynamic outcomes were retrospectively evaluated.

Results

Three asymptomatic strokes (12.5%) occurred within 30 postoperative days in each group. Postoperative strokes after 30 days occurred in 3 patients (12.5%) with 3 hemorrhagic events and 1 cerebral infarction, only in indirect bypass, while no stroke occurred in hemispheres treated with combined bypass. The revascularization area relative to supratentorial area was significantly greater in combined bypass than in indirect bypass, both in short-term and long-term periods (64.9% versus 43.9% in short-term and 75.7% versus 54.9% in long-term; P < .001, respectively). Hemodynamic outcomes showed significantly greater increases in acetazolamide-challenged cerebral blood flow (CBF_acz) during short-term follow-up (P = .04) and in both basal CBF (CBF_bas) and CBF_acz during long-term follow-up (P = .014 and P = .009, respectively) in combined bypass than in indirect bypass.

Conclusion

Combined bypass may be a more effective treatment option for MMD based on its higher revascularization area and favorable hemodynamic results compared to indirect bypass in the same patient.

Purpose

The follow-up routine for patients with idiopathic normal pressure hydrocephalus (iNPH) after shunt surgery differs across medical centers. Shunt surgery is not without risks, with complications emerging at various times after the procedure. The aim was to explore the timing and methods of detecting complications following ventriculoperitoneal shunt surgery for iNPH.

Methods

This retrospective study examined patients who underwent shunt surgery for iNPH at Uppsala University Hospital between 2011 and 2018. The cohort comprised 491 patients. Postoperative complications within the first 12 months were recorded from medical records. Complications were classified by type, and the method or event that first indicated the complication was documented.

Results

Of the 491 patients, 102 (20.8%) experienced complications during the one-year follow-up period, with a shunt revision rate of 15.5% (76 patients requiring reoperation). Subdural hematomas/hygromas were the most common complications, with 27 cases; only three required surgical intervention. Most complications were identified through additional appointments triggered by patient-reported symptoms (31.4%), while the planned follow-up routine with CT scans and planned follow-up visits together accounted for 56% of the detections. The 3-month and 12-month follow-up visits detected similar proportions of complications (12.7% and 11.8%, respectively).

Conclusion

The majority of the complications were detected at a planned visit or investigation. Given the cognitive impairments in iNPH patients and that signs of shunt dysfunction can be subtle, a structured follow-up routine is important for timely detection of complications. The findings suggest that both CT scans and planned follow-up visits are critical components of effective postoperative monitoring.