Neurochirurgie最新文献

Background and Objectives

The pathophysiology of spontaneous vertebral artery dissecting aneurysms (SVADA) is poorly understood. Our goal is to investigate the hemodynamic factors contributing to their formation using computational fluid dynamics (CFD) and deep learning algorithms.

Methods

We have developed software that can use patient imagery as input to recreate the vertebrobasilar arterial system, both with and without SVADA, which we used in a series of three patients. To obtain the kinematic blood flow data before and after the aneurysm forms, we utilized numerical methods to solve the complex Navier-Stokes partial differential equations. This was accomplished through the application of a finite volume solver (OpenFoam/Helyx OS). Additionally, we trained a neural ordinary differential equation (NODE) to learn and replicate the dynamical streamlines obtained from the computational fluid dynamics (CFD) simulations.

Results

In all three cases, we observed that the equilibrium of blood pressure distributions across the VAs, at a specific vertical level, accurately predicted the future SVADA location. In the two cases where there was a dominant VA, the dissection occurred on the dominant artery where blood pressure was lower compared to the contralateral side. The SVADA sac was characterized by reduced wall shear stress (WSS) and decreased velocity magnitude related to increased turbulence. The presence of a high WSS gradient at the boundary of the SVADA may explain its extension. Streamlines generated by CFD were learned with a neural ordinary differential equation (NODE) capable of capturing the system’s dynamics to output meaningful predictions of the flow vector field upon aneurysm formation.

Conclusion

In our series, asymmetry in the vertebrobasilar blood pressure distributions at and proximal to the site of the future SVADA accurately predicted its location in all patients. Deep learning algorithms can be trained to model blood flow patterns within biological systems, offering an alternative to the computationally intensive CFD. This technology has the potential to find practical applications in clinical settings.

Background

Vertebral artery dissection (VAD) is an infrequent source of subarachnoid hemorrhage (SAH), with a high mortality rate, primarily due to the risk of rebleeding both before and after medical intervention. This paper provides a comprehensive analysis of the anatomy, pathophysiology, clinical presentation, treatment strategies, and outcomes of intracranial vertebral artery dissections that result in subarachnoid hemorrhage.

Methods

Comprehensive five-year literature review (2018–2022) and a retrospective analysis of patient records from our institution between 2016 and 2022. We included studies with a minimum of 5 patients.

Results

The study incorporated ten series from the literature and 22 cases from CHUM. Key anatomical factors increasing the risk of VAD include the vertebral artery’s origin from the aortic arch, asymmetry of the vertebral artery, and its tortuosity. Patients may display specific collagen and genetic abnormalities. The occurrence of VAD appears to be more prevalent in men. Those with a ruptured intracranial VAD typically show prodromal symptoms and present with severe SAH. Rebleeding within the first 24 h is frequent. While standard imaging methods are usually adequate for VAD diagnosis, they may not provide detailed information about the perforator anatomy. Treatment approaches include both deconstructive and reconstructive methods.

Conclusion

Ruptured VAD is a critical, life-threatening condition. Many patients have a poor neurological status at presentation, and rebleeding prior to treatment is a significant concern. Deconstructive techniques are most effective in preventing rebleeding, whereas the efficacy of reconstructive techniques needs more investigation.

The vertebral arteries represent in the adult the main blood supply of the posterior cranial fossa, even if they appear relatively late during the embryological life.

We reviewed all the most important steps of the vertebral artery’s embryological development and the most common variants that can occur in the adult.

The aim of this review is to summarize the main events of the development of this artery and to give an embryological explication for the most common variants of this artery.

An in-depth understanding of the anatomy of the craniocervical junction (CCJ) is indispensable in skull base neurosurgery. In this paper, we discuss the osteology of the occipital bone, the atlas (C1) and axis (C2), the ligaments and the muscle anatomy of the CCJ region and their relationships with the vertebral artery. We will also discuss the trajectory of the vertebral artery and review the anatomy of the jugular foramen and lower cranial nerves (IX to XII). The most important surgical approaches to the CCJ, including the far lateral approach, the anterolateral approach of Bernard George and the endoscopic endonasal approach, will be discussed to review the surgical anatomy.

Background

The role of Gamma Knife radiosurgery (GKRS) in recurrent glioblastoma remains unclear. The purpose of this study is to evaluate the effects of GKRS in a group of patients with recurrent glioblastoma, focusing on survival and safety.

Methods

Patients undergoing GKRS for recurrent glioblastoma between September 2014 and April 2019 were included in this study. Relevant clinical and radiosurgical data, including GKRS-related complications, were recorded and analyzed. Overall survival (OS), local progression free survival (LPFS) and prognostic factors for outcome were thoroughly evaluated.

Results

Fifty-three patients were analyzed (24 female, 29 male). The median age was 50 years (range, 19–78 years). The median GKRS treatment volume was 35.01 cm³ (range, 2.38-115.57 cm³). Twenty patients (38%) were treated with single fraction GKRS, while 33 (62%) were treated with GKRS-based hypofractionated stereotactic radiotherapy (HSRT). The median prescription dose for single fraction GKRS, 3-fractions HSRT and 5-fractions HSRT were 16 Gy (range, 10−20 Gy), 27 Gy (range, 18−33 Gy) and 25 Gy (range, 25−30 Gy), respectively. The median LPFS and OS times were 8.1 months and 11.4 months after GKRS, respectively. HSRT and Bevacizumab were associated with improved LPFS, while HSRT alone was associated with longer OS.

Conclusion

Our findings suggested that HRST would likely improve LPFS and OS in definite settings; the addition of Bevacizumab to GKRS was associated with increased rates of local control. No major complications were reported. Further prospective studies are warranted to confirm our findings.

Degenerative cervical myelopathy is a pathology frequently encounterd in the neurosurgical practice. Posterior ostophytes located at the posterior part of the vertebral endplate are frequently involved in the reduction of the cervical canal. We propose a description of the technique used in our department to drill this posterior part of the endplate safely with the help of modern instruments and microscope magnification.The bony resection being performed with diamond burr, we believe this technique less traumatic on the spinal cord than repeated insertions of rongeur. Radiological result shows a nice enlargment of the cervical canal. This technique offers a less invasive alternative to corporectomy in cases of two-level stenosis.

Background

Anterior temporal hollowing (ATH) leads to unattractive facial asymmetry and significant distress for the patient. This study aimed to correct ATH by a prefabricated cranioplasty using soft-tissue volume augmentation created by 3D printing and to evaluate the esthetic improvement.

Methods

This prospective study was conducted on 19 patients with ATH after brain surgery. Quantitative assessment used Materialized Mimics® and Images® to compare defect volume and quantitative measurement of the “defect value” pre- and post-PMMA implantation. Qualitative assessment was rated by patients on VAS pre- and 6 months post-surgery.

Results

The mean defect value decreased significantly with the innovative PMMA implant, from 2.42 ± 0.57 cm to 0.57 ± 0.45 cm (p < 0.01). There was a statistically significant reduction between pre- and postoperative defect value: 1.85 ± 0.48 (p < 0.01; 95% CI 2.08–1.61). After PMMA cranial implantation, 100% of patients reported esthetic improvement, 79% (15 out of 20) rating their esthetic improvement with the highest possible VAS score: mean VAS rating, 0.84 ± 1.2 preoperatively, and 4.63 ± 0.83 postoperatively, for a significant mean improvement of 3.789 ± 1.273 (p < 0.01; 95% CI 3.176–4.403).

Conclusions

The innovative PMMA cranial implants created by advanced customized 3D technology successfully managed ATH. This could be a therapeutic alternative for correcting ATH and can be routinely employed in clinical practice.

Objective

The use of endoscopic assistance in retrosigmoid approach for tumors of the cerebellopontine angle brought undoubted technological advantages in skull base surgery.

Nonetheless, the use of the endoscope is not as widespread as it could be.

The aim of the study is to analyze the impressions of neurosurgeons and otologists with different experience in vestibular schwannoma surgery, experiencing the introduction of the endoscope in surgical daily practice.

Methods

All patients undergoing vestibular schwannoma surgery were recruited in the period from January 2019 to December 2020. The endoscope-assistance and a minimum follow-up of 12 months were considered inclusion criteria. An eight items questionnaire was administered to the surgeons who used endoscope-assistance during surgery.

Results

A total number of 20 patients were recruited. Five surgeons experienced the use of 0° and 45° optics in the “pre-resection” and “intra-meatal” phases of the procedures. The survey gave positive feedbacks on the introduction of the endoscope in vestibular schwannoma resection. The main drawback was the difficulty to manage the use of angled optics.

Conclusions

Despite the known limitations of the study, the idea of investigating surgeons’ impressions on the use of the endoscope could be another motif to explain why this instrument and its diffusion is limited despite its advantages in vestibular schwannoma surgery.