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Diffusion tensor imaging (DTI) is commonly used to establish three-dimensional mapping of white-matter bundles in the supraspinal central nervous system. DTI has also been the subject of many studies on cranial and peripheral nerves. This non-invasive imaging technique enables virtual dissection of nerves in vivo and provides specific measurements of microstructural integrity. Adverse effects on the lumbosacral plexus may be traumatic, compressive, tumoral, or malformative and thus require dedicated treatment. DTI could lead to new perspectives in pudendal neuralgia diagnosis and management. We performed a systematic review of all articles or posters reporting results and protocols for lumbosacral plexus mapping using the DTI technique between January 2011 and December 2023. Twenty-nine articles published were included. Ten studies with a total of 351 participants were able to track the lumbosacral plexus in a physiological context and 19 studies with a total of 402 subjects tracked lumbosacral plexus in a pathological context. Tractography was performed on a 1.5T or 3T MRI system. DTI applied to the lumbosacral plexus and pudendal nerve is feasible but no microstructural normative value has been proposed for the pudendal nerve. The most frequently tracking parameters used in our review are: 3T MRI, b-value of 800 s/mm2, 33 directions, 3 × 3 × 3 mm3, AF threshold of 0.1, minimum fiber length of 10 mm, bending angle of 30°, and 3DT2 TSE anatomical resolution. Increased use of DTI could lead to new perspectives in the management of pudendal neuralgia due to entrapment syndrome, whether at the diagnostic, prognostic, or preoperative planning level. Prospective studies of healthy subjects and patients with the optimal acquisition parameters described above are needed to establish the accuracy of MR tractography for diagnosing pudendal neuralgia and other intrapelvic nerve entrapments. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to characterize spinal cord microstructure in healthy subjects using high angular resolution diffusion imaging (HARDI) and tractography., Methods: Forty-nine healthy subjects (18-50 years, divided into 2 age groups) were included in a prospective study. HARDI of the cervical spinal cord were acquired using a 3T MRI scanner with: 64 directions, b‑value: 1000s/mm 2 , reduced field-of-view (zonally magnified oblique multi-slice), and opposed phase-encoding directions. Distortions were corrected using the FSL software package. Fiber tracking was performed using a deterministic approach with DSI-Studio software. Tensor metrics-fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD)-and tractography statistics were then extracted, at each spine level, and after grey-white matter segmentation., Results: The microstructural organization of the spinal cord differed between upper and lower cervical spine levels: FA, and AD significantly decreased (p < 0.001); and RD significantly increased (p < 0.05) in lower levels, demonstrating changes in axonal density and myelinated fibers according to a cranio-caudal axis. FA, MD, AD, and RD values were significantly higher in spinal cord white matter (p < 0.0001), compared to grey matter. Age was not associated with a significant change in FA, while there is for MD, AD and RD (p < 0.05). Spinal cord tractography may provide information on the architectural organization of fibers and spinal tracts., Conclusion: This study proposes a database in cervical spinal cord HARDI, allowing to study the microstructural organization of the spinal cord in healthy subjects, and providing a foundation for comparison with patients presenting spinal cord pathologies., Competing Interests: Conflict of interest: C. Dauleac, A. Boukhari, T. Jacquesson, C. Frindel and F. Cotton declare that they have no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Objective: Trigeminal schwannoma (TS), though a rare and benign tumor, becomes a significant surgical challenge due to its intricate location. This study aims to detail the long-term functional outcomes and tumor control post-surgical resection., Method: We analyzed a multicentric retrospective cohort of 39 patients operated on for a TS in five tertiary centers between January 1993 and July 2022., Results: Six TS (15%) were in the middle fossa (type M), two (5%) in the posterior fossa (type P), and two (5%) were extracranial (type E). Twenty-nine (75%) were Dumbbell shape: Eighteen (47%) were MP type, seven (18%) were MPE type, and four (10%) were ME type. Fifth nerve symptoms were the foremost preoperative complaint: hypesthesia (51%), trigeminal neuralgia (36%), and paresthesia (30%). We report a favorable evolution course for 61% of preexisting deficits (half of patients with preoperative paresthesia and neuralgia improved while only 5% of preoperative hypesthesia improved). Postoperative hypesthesia was the most frequent de novo deficit 14 (74%) and resolved in solely half the cases. Various approaches were used according to tumor type. Gross total resection (GTR), Subtotal resection (STR), and partial resection (PR) were achieved in respectively 33% (N = 13), 10% (N = 4), and 56% (N = 22) of patients. The mean clinical and radiological FU was 63 months (12 - 283 months). GTR led to no sign of recurrence (mean FU: 60 months - range: 12-283 months). For STR or PR (67%): 23 (88%) were assigned to a Wait-&-rescan policy (WS group) which offered stability in 70% (N = 16). Three cases (8%) underwent a complementary GKS (GammaKnife) on the residual lesion (GK group) without tumor change., Conclusion: For large TS, the completeness of resection must consider the potential functional burden of surgery. With giant infiltrating lesions, a strategy of planned subtotal resection, complemented by radiosurgery, either complementary or uppon regrowth, may provide similar oncological outcomes., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Here, we report a very rare case of spontaneous intraventricular tension pneumocephalus. This case concerns a 40-year-old patient with medical history of a tumor of the pineal region and a secondary hydrocephalus treated by multiple ventriculoperitoneal shunts. He presented in the emergency room because of unusual headaches, nausea, and visual loss. In addition, he reported slight rhinorrhea in the past few weeks. The initial brain computed tomography scan revealed a spontaneous intraventricular tension pneumocephalus. There was no history of recent head trauma and no sign of disconnection of the shunt system. A complementary radiologic assessment including a thin-slice bone computed tomography scan and a radioisotope cisternography revealed an osseous defect and an isotope leakage at the junction between the tegmen tympani and the squamous part of the left temporal bone. A middle cranial fossa surgery was performed to repair the osteo-meningeal breach., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This pilot study aimed to investigate the interest of high angular resolution diffusion imaging (HARDI) and tractography of the spinal cord (SC) in the management of patients with intramedullary tumors by providing predictive elements for tumor resection. Eight patients were included in a prospective study. HARDI images of the SC were acquired using a 3T MRI scanner with a reduced field of view. Opposed phase-encoding directions allowed distortion corrections. SC fiber tracking was performed using a deterministic approach, with extraction of tensor metrics. Then, regions of interest were drawn to track the spinal pathways of interest. HARDI and tractography added value by providing characteristics about the microstructural organization of the spinal white fibers. In patients with SC tumors, tensor metrics demonstrated significant changes in microstructural architecture, axonal density, and myelinated fibers (all, p < 0.0001) of the spinal white matter. Tractography aided in the differentiation of tumor histological types (SC-invaded vs. pushed back by the tumor), and differentiation of the spinal tracts enabled the determination of precise anatomical relationships between the tumor and the SC, defining the tumor resectability. This study underlines the value of using HARDI and tractography in patients with intramedullary tumors, to show alterations in SC microarchitecture and to differentiate spinal tracts to establish predictive factors for tumor resectability.

The use of diffusion tensor imaging (DTI) has seen significant development over the last two decades, in particular with the development of the tractography of association tracts for preoperative planning of surgery. However, projection tracts are difficult to differentiate from one another and tractography studies have failed to reconstruct these ascending/descending pathways from/to the spinal cord. The present study proposes an atlas of regions of interest (ROIs) designed specifically for projection tracts tractography. Forty-nine healthy subjects were included in this prospective study. Brain DTI was acquired using the same 3 T MRI scanner, with 32 diffusion directions. Distortions were corrected using the FSL software package. ROIs were drawn using the anterior commissure (AC)-posterior commissure (PC) line on the following landmarks: the pyramid for the corticospinal tract, the medio-caudal part of the red nucleus for the rubrospinal tract, the pontine reticular nucleus for corticoreticular tract, the superior and inferior cerebellar peduncles for, respectively, the anterior and posterior spinocerebellar tract, the gracilis and cuneatus nucleus for the dorsal columns, and the ventro-posterolateral nucleus for the spinothalamic tract. Fiber tracking was performed using a deterministic algorithm using DSI Studio software. ROI coordinates, according to AC-PC line, were given for each tract. Tractography was obtained for each tract, allowing tridimensional rendering and comparison of tracking metrics between tracts. The present study reports the accurate design of specific ROIs for tractography of each projection tract. This could be a useful tool in order to differentiate projection tracts at the spinal cord level., (© 2024 Anatomical Society.)

The aim was to identify predictors of progression in a series of patients managed for an intracranial hemangioblastoma, in order to guide the postoperative follow-up modalities. The characteristics of 81 patients managed for an intracranial hemangioblastoma between January 2000 and October 2022 were retrospectively analyzed. The mean age at diagnosis was of 48 ± 16 years. Eleven (14%) patients had von Hippel-Lindau disease. The most frequent tumor location was the cerebellar hemispheres ( n = 51, 65%) and 11 (14%) patients had multicentric hemangioblastomas. A gross total resection was achieved in 75 (93%) patients. Eighteen (22%) patients had a local progression, with a median progression-free survival of 56 months 95% CI [1;240]. Eleven (14%) patients had a distant progression (new hemangioblastoma and/or growth of an already known hemangioblastoma). Local progression was more frequent in younger patients (39 ± 14 years vs. 51 ± 16 years; p = 0.005), and those with von Hippel-Lindau disease ( n = 8, 44% vs. n = 3, 5%, p < 0.0001), multiple cerebral locations ( n = 3, 17% vs. n = 2, 3%, p = 0.02), and partial tumoral resection ( n = 4, 18% vs. n = 1, 2%, p = 0.0006). Therefore, it is advisable to propose a postoperative follow-up for at least 10 years, and longer if at least one predictor of progression is present.

Objective: Central pontine myelinolysis (CPM) is a rare demyelinating disease that affects the pons and which can cause extreme disabilities such as locked-in syndrome (LIS) in the initial phase. The aim of the study was to describe the evolution over a 12-month period of two patients with CPM causing an initial LIS., Method: We retrospectively report the unexpected clinical outcome of these two patients in relation with the anatomical damages documented by brain MRI, associated with diffusion tensor imaging and reconstruction of corticospinal tracts in tractography. The following clinical parameters systematically assessed at 3, 6, 9, and 12 months: muscle testing on 12 key muscles (Medical Research Council), prehension metrics (box and block test and purdue pegboard), and independence for acts of daily living (functional independence measure)., Results: Both patients showed a progressive recovery beginning between 2 and 3 months after the onset of symptoms, leading to almost complete autonomy at 12 months (FIM > 110), with motor strength greater than 4/5 in all joint segments (MRC > 50/60). On brain MRI with tractography, CST appeared partially preserved at pons level., Interpretation: The possibility of a near-complete functional recovery at 12 months is important to consider given the ethical issues at stake and the discussions about limiting care that may take place initially. It seems to be the consequence of reversible myelin damage combined with partially preserved neurons. Development of collateral pathways or resolution of conduction block may explain this recovery. MRI comprising DTI and tractography could play a key role in the prognosis of motor recovery., (© 2024 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background: Understanding and teaching the three-dimensional architecture of the brain remains difficult because of the intricate arrangement of grey nuclei within white matter tracts. Although cortical area functions have been well studied, educational and three-dimensional descriptions of the organization of deep nuclei and white matter tracts are still missing., Objective: We propose herein a detailed step-by-step dissection of the lateral aspect of a left hemisphere using the Klingler method and provide high-quality stereoscopic views with the aim to help teach medical students or surgeons the three-dimensional anatomy of the brain., Methods: Three left hemispheres were extracted and prepared. Then, according to the Klingler method, dissections were carried out from the lateral aspect. Photographs were taken at each step and were modified to provide stereoscopic three-dimensional views., Results: Gray and white structures were described: cortex, claustrum, putamen, pallidum, caudate nucleus, amygdala; U-fibers, external and internal capsules, superior longitudinal fasciculus, frontal aslant fasciculus, uncinate fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, corticospinal fasciculus, corona radiata, anterior commissure, and optic radiations., Conclusion: This educational stereoscopic presentation of an expert dissection of brain white fibers and basal ganglia would be of value for theoretical or hands-on teaching of brain anatomy; labeling and stereoscopy could, moreover, improve the teaching, understanding, and memorizing of brain anatomy. In addition, this could be also used for the creation of a mental map by neurosurgeons for the preoperative planning of brain tumor surgery., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

The frontal aslant tract (FAT) is a crucial neural pathway of language and speech, but little is known about its connectivity and segmentation differences across populations. In this study, we investigate the probabilistic coverage of the FAT in a large sample of 1065 young adults. Our primary goal was to reveal individual variability and lateralization of FAT and its structure-function correlations in language processing. The study utilized diffusion MRI data from 1065 subjects obtained from the Human Connectome Project. Automated tractography using DSI Studio software was employed to map white matter bundles, and the results were examined to study the population variation of the FAT. Additionally, anatomical dissections were performed to validate the fiber tracking results. The tract-to-region connectome, based on Human Connectome Project-MMP parcellations, was utilized to provide population probability of the tract-to-region connections. Our results showed that the left anterior FAT exhibited the most substantial individual differences, particularly in the superior and middle frontal gyrus, with greater variability in the superior than the inferior region. Furthermore, we found left lateralization in FAT, with a greater difference in coverage in the inferior and posterior portions. Additionally, our analysis revealed a significant positive correlation between the left FAT inferior coverage area and the performance on the oral reading recognition (p = .016) and picture vocabulary (p = .0026) tests. In comparison, fractional anisotropy of the right FAT exhibited marginal significance in its correlation (p = .056) with Picture Vocabulary Test. Our findings, combined with the connectivity patterns of the FAT, allowed us to segment its structure into anterior and posterior segments. We found significant variability in FAT coverage among individuals, with left lateralization observed in both macroscopic shape measures and microscopic diffusion metrics. Our findings also suggested a potential link between the size of the left FAT's inferior coverage area and language function tests. These results enhance our understanding of the FAT's role in brain connectivity and its potential implications for language and executive functions., (© 2024 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.)

Purpose: To assess interrater reliability and examiners' characteristics, especially specialty, associated with scoring of neurology objective structured clinical examination (OSCE)., Material and Methods: During a neurology mock OSCE, five randomly chosen students volunteers were filmed while performing 1 of the 5 stations. Video recordings were scored by physicians from the Lyon and Clermont-Ferrand university teaching hospitals to assess students performance using both a checklist scoring and a global rating scale. Interrater reliability between examiners were assessed using intraclass coefficient correlation. Multivariable linear regression models including video recording as random effect dependent variable were performed to detect factors associated with scoring., Results: Thirty examiners including 15 (50%) neurologists participated. The intraclass correlation coefficient of checklist scores and global ratings between examiners were 0.71 (CI95% [0.45-0.95]) and 0.54 (CI95% [0.28-0.91]), respectively. In multivariable analyses, no factor was associated with checklist scores, while male gender of examiner was associated with lower global rating ( β  coefficient = -0.37; CI 95% [-0.62-0.11])., Conclusions: Our study demonstrated through a video-based scoring method that agreement among examiners was good using checklist scoring while moderate using global rating scale in neurology OSCE. Examiner's specialty did not affect scoring whereas gender was associated with global rating scale.

Objectives: We aimed to describe diagnostic, management, and outcome of bone flap-related osteomyelitis after cranioplasty., Methods: Patients followed up in our tertiary care hospital for bone flap-related osteomyelitis after cranioplasty were included in a retrospective cohort (2008-2021). Determinants of treatment failure were assessed using logistic regression and Kaplan-Meier curves analysis., Results: The 144 included patients (81 [56.3%] males; median age 53.4 [interquartile range [IQR], 42.6-62.5] years) mostly presented wound abnormalities (n = 115, 79.9%). All infections were documented, the main pathogens being Staphylococcus aureus (n = 64, 44.4%), Cutibacterium acnes (n = 57, 39.6%), gram-negative bacilli (n = 40, 27.8%) and/or non-aureus staphylococci (n = 34, 23.6%). Surgery was performed in 140 (97.2%) cases, for bone flap removal (n = 102, 72.9%) or debridement with flap retention (n = 31, 22.1%), along with 12.7 (IQR, 8.0-14.0) weeks of antimicrobial therapy. After a follow-up of 117.1 (IQR, 62.5-235.5) weeks, 37 (26.1%) failures were observed: 16 (43.2%) infection persistence, three (8.1%) relapses, 22 (59.5%) superinfections and/or two (1.7%) infection-related deaths. Excluding superinfections, determinants of the 19 (13.4%) specific failures were an index craniectomy for brain tumor (odds ratio = 4.038, P = 0.033) and curettage of bone edges (odds ratio = 0.342, P = 0.048)., Conclusion: Post-craniectomy bone flap osteomyelitis are difficult-to-treat infection, necessitating prolonged antimicrobial therapy with appropriate surgical debridement, and advocating for multidisciplinary management in dedicated reference centers., Competing Interests: Declaration of competing interest The authors have no competing interests to declare., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Anterior skull base lesions could be reached by different approaches (subfrontal, pterional, interhemispheric, etc.). In selected cases, the frontal trans-sinusal approach is an effective alternative to conventional techniques., Methods: We present our technique to perform a frontal trans-sinusal approach in a patient affected by a large olfactory groove meningioma., Discussion-Conclusion: The frontal trans-sinusal approach allows to approach safely lesions of the median anterior cranial fossa. This approach provides lower brain retraction, easier access to olfactory grooves, and earlier tumor devascularization. However, it remains limited to patients with large-sized frontal sinuses and entails some postoperative risks such as mucocele or CSF leak., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Despite recent improvements in diffusion-weighted imaging, spinal cord tractography is not used in routine clinical practice because of difficulties in reconstructing tractograms, with a pertinent tri-dimensional-rendering, in a long post-processing time. We propose a new full tractography approach to the cervical spinal cord without extensive manual filtering or multiple regions of interest seeding that could help neurosurgeons manage various spinal cord disorders. Four healthy volunteers and two patients with either cervical intramedullary tumors or spinal cord injuries were included. Diffusion-weighted images of the cervical spinal cord were acquired using a Philips 3 Tesla machine, 32 diffusion directions, 1,000 s/mm 2 b -value, 2 × 2 × 2 mm voxel size, reduced field-of-view (ZOOM), with two opposing phase-encoding directions. Distortion corrections were then achieved using the FSL software package, and tracking of the full cervical spinal cord was performed using the DSI Studio software (quantitative anisotropy-based deterministic algorithm). A unique region of avoidance was used to exclude everything that is not of the nervous system. Fiber tracking parameters used adaptative fractional anisotropy from 0.015 to 0.045, fiber length from 10 to 1,000 mm, and angular threshold of 90°. In all participants, a full cervical cord tractography was performed from the medulla to the C7 spine level. On a ventral view, the junction between the medulla and spinal cord was identified with its pyramidal bulging, and by an invagination corresponding to the median ventral sulcus. On a dorsal view, the fourth ventricle-superior, middle, and inferior cerebellar peduncles-was seen, as well as its floor and the obex; and gracile and cuneate tracts were recognized on each side of the dorsal median sulcus. In the case of the intramedullary tumor or spinal cord injury, the spinal tracts were seen to be displaced, and this helped to adjust the neurosurgical strategy. This new full tractography approach simplifies the tractography pipeline and provides a reliable 3D-rendering of the spinal cord that could help to adjust the neurosurgical strategy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Dauleac, Frindel, Pélissou-Guyotat, Nicolas, Yeh, Fernandez-Miranda, Cotton and Jacquesson.)

Brain invasion has not been recognized as a standalone criterion for atypical meningioma by the WHO classification until 2016. Since the 2007 edition suggested that meningiomas harboring brain invasion could be classified as grade 2, brain invasion study was progressively strengthened in our center, based on a strong collaboration between neurosurgeons and neuropathologists regarding sample orientation and examination. Practice changes were considered homogeneous enough in 2011. The aim of the present study was to evaluate the impact of gross practice change on the clinical and pathological characteristics of intracranial meningiomas classified as grade 2.The characteristics of consecutive patients with a grade 2 meningioma surgically managed before (1998-2005, n = 125, group A) and after (2011-2014, n = 166, group B) practices changed were retrospectively reviewed.Sociodemographical and clinical parameters were comparable in groups A and B, and the median age was 62 years in both groups (p = 0.18). The 5-year recurrence rates (23.2% vs 29.5%, p = 0.23) were similar. In group A, brain invasion was present in 48/125 (38.4%) cases and was more frequent than in group B (14/166, 8.4%, p < 0.001). In group A, 33 (26.4%) meningiomas were classified as grade 2 solely based on brain invasion (group A SBI ), and 92 harbored other grade 2 criteria (group A OCA ). Group A SBI meningiomas had a similar median progression-free survival compared to groups A OCA (68 vs 80 months, p = 0.24) and to A OCA and B pooled together (n = 258, 68 vs 90 months, p = 0.42).An accurate assessment of brain invasion is mandatory as brain invasion is a strong predictor of meningioma progression., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Surgical and clinical management of craniopharyngiomas is associated with high long-term morbidity especially in the case of hypothalamic involvement. Improvements in knowledge of craniopharyngioma molecular biology may offer the possibility of safe and effective medical neoadjuvant treatments in a subset of patients harboring papillary subtype tumors with a BRAFV600E mutation., Method: We report herein two cases of tubero-infundibular and ventricular Papillary Craniopharyngiomas in which BRAF/MEK inhibitor combined therapy was used as adjuvant (Case 1) or neoadjuvant (Case 2) treatment, with a 90% reduction in tumor volume observed after only 5 months. In Case 2 the only surgical procedure used was a minimal invasive biopsy by the trans-ventricular neuroendoscopic approach. As a consequence, targeted therapy was administered in purely neoadjuvant fashion. After shrinkage of the tumor, both patients underwent fractionated radiotherapy on the small tumor remnant to achieve long-term tumor control. A review of a previously reported case has also been performed., Result: This approach led to tumor control with minimal long-term morbidity in both cases. No side effects or complications were reported after medical treatment and adjuvant radiotherapy., Conclusion: Our experience and a review of the literature argue for a change in the current treatment paradigm for Craniopharyngiomas (CPs). In giant and invasive tumors, confirmation of BRAFV600E mutated PCPs by biopsy and BRAF/MEK inhibitor therapy before proposing other treatments may be useful to improve long term outcomes for patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Calvanese, Jacquesson, Manet, Vasiljevic, Lasolle, Ducray, Raverot and Jouanneau.)

Fiber tractography enables the in vivo reconstruction of white matter fibers in 3 dimensions using data collected by diffusion tensor imaging, thereby helping to understand functional neuroanatomy. In a pre-operative context, it provides essential information on the trajectory of fiber bundles of medical interest, such as cranial nerves. However, the optimization of tractography parameters is a time-consuming process and requires expert neuroanatomical knowledge, making the use of tractography difficult in clinical routine. Tractogram filtering is a method used to isolate the most relevant fibers. In this work, we propose to use filtering as a post-processing of tractography to avoid the manual optimization of tracking parameters and therefore making a step forward automation of tractography. To question the feasibility of automated tractography of cranial nerves, we perform an analysis of main cranial nerves on a series of patients with skull base tumors. A quantitative evaluation of the filtering performance of two state-of-the-art and a new entropy-based methods is carried out on the basis of reference tractograms produced by experts. Our approach proves to be more stable in the selection of the optimal filtering threshold and turns out to be interesting in terms of computational time complexity., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Decroocq, Des Ligneris, Poquillon, Vincent, Aubert, Jacquesson and Frindel.)

Purpose: The main anatomic variations should be taught along with the classical anatomy curriculum, since they can mislead both diagnosis and treatment. We report here a clinical and radiological case of left C6 cervicobrachial neuralgia recurrence due to a vertebral artery loop, we then describe 13 published cases of such neurovascular conflicts., Case: A 51-year-old woman suffered from recurrence of C6 cervicobrachial neuralgia after an initial C5-C6 decompression-fusion. Additional cervical angio-MR and CT scans found a tortuous aspect of the left vertebral artery that came into conflict with the left C6 spinal root, just after its emergence of the C5-C6 intervertebral foramen. A large posterior decompression was performed including a C5 and C6 left lateral mass resection to enlarge the foraminal space. The vertebral artery was kept in place. The patient reported a slow but consistent decrease in pain that disappeared after 3 months. Thirteen cases of a compressive vertebral loop are thereafter detailed., Conclusions and Discussion: Vascular precursors disarrangements can lead to a vertebral artery loop in contact with emerging cervical roots and potential clinical impact. This differential diagnosis should be considered for cervico-brachial neuralgia management. Moreover, the present case highlights the key role of a careful preoperative imaging assessment, as well as the need for robust knowledge of anatomy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Background: The anatomy of both the skull and the brain offers many landmarks that could lead surgery. Cranial "craniometric" key points were described many years ago, and then, cerebral key points-along sulci and gyri-were detailed more recently for microneurosurgical approaches that can reach deep structures while sparing the brain. Nonetheless, this anatomic knowledge is progressively competed by new digital devices, such as imaging guidance systems, although they can be misleading., Objective: To summarize cranial and sulcal key points and their related anatomic structures to renew their interest in modern neurosurgery and help surgical anatomy teaching., Methods: After a literature review collecting anatomic key points of skull and brain, specimens were prepared and images were taken to expose skull and brain from lateral, superior, posterior, and oblique views. A high-definition camera was used, and images obtained were modified, superimposing both key points and underlying anatomic structures., Results: From 4 views, 16 cranial key points were depicted: anterior and superior squamous point, precoronal and retrocoronal point, superior sagittal point, intraparietal point, temporoparietal point, preauricular point, nasion, bregma, stephanion, euryon, lambda, asterion, opisthocranion, and inion. These corresponded to underlying cerebral key points and relative brain parts: anterior and posterior sylvian point, superior and inferior rolandic point, supramarginal and angular gyri, parieto-occipital sulcus, and various meeting points between identifiable sulci. Stereoscopic views were also provided to help learning these key points., Conclusion: This comprehensive overview of the cranial and sulcal key points could be a useful tool for any neurosurgeon who wants to check her/his surgical route and make the surgery more "gentle, safe, and accurate.", (Copyright © Congress of Neurological Surgeons 2021. All rights reserved.)