A comprehensive review of the vertebral artery anatomy

BACKGROUND

The vertebral arteries (VA) play a critical role by supplying nearly one-third of the brain's blood flow, predominantly contributing to the posterior circulation. These arteries may need to be exposed in a various cranial and cervical procedures and offers access to investigate or treat vascular lesions by endovascular means related to the posterior circulation. Given its complex anatomy, which is subject to numerous variations, and its role in supplying vital brain regions, a thorough understanding of the VA's anatomy is paramount for any related procedure.

OBJECTIVE

To provide a comprehensive overview of vertebral artery anatomy and its relevance in contemporary clinical practice.

METHODS

Dissection of the entire vertebral artery length using cadaveric specimen, combined with a comprehensive literature review.

RESULTS

The vertebral artery can be subdivided into four segments. Each of these segments has its own unique topographic anatomy with its variations, anastomoses, and significance in surgery.

CONCLUSION

As surgical and endovascular techniques continue to evolve with technological improvements, we are now more equipped than ever to manage complex lesions involving the VA. However, with its increasingly complexity comes the necessity for a deeper and more comprehensive understanding of the VA. Possessing the detailed knowledge of the VA is vital for the successful execution of any procedure involving it.

Composition of encephalic arteries and origin of the basilar artery are different between vertebrates

Intracranial arterial anatomy is lacking for most mammalian and non-mammalian model species, especially concerning the origin of the basilar artery (BA). Enhancing the knowledge of this anatomy can improve animal models and help understanding anatomical variations in humans. We have studied encephalic arteries in three different species of birds and eight different species of mammals using formalin-fixed brains injected with arterial red latex. Our results and literature analysis indicate that, for all vertebrates, the internal carotid artery (ICA) supplies the brain and divides into two branches: a cranial and a caudal branch. The difference between vertebrates lies in the caudal branch of the ICA. For non-mammalian, the caudal branch is the origin of the BA, and the vertebral artery (VA) is not involved in brain supply. For mammals, the VA supplies encephalic arteries in two different ways. In the first type of organization, mostly found in ungulates, the carotid rete mirabile supplies the encephalic arteries, the caudal branch is the origin of the BA, and the VA is indirectly involved in carotid rete mirabile blood supply. The second type of encephalic artery organization for mammals is the same as in humans. The caudal branch of the ICA serves as the posterior communicating artery, and the BA originates from both VAs. We believe that knowledge of comparative anatomy of encephalic arteries contributes to a better understanding of animal models applicable to surgical or radiological techniques. It improves the understanding of rare encephalic variations that may be present in humans.

Association between post-operative hPG80 (circulating progastrin) detectable level and worse prognosis in glioblastoma

BACKGROUND

Patients with glioblastomas have a dismal prognosis, and there is no circulating predictive or prognostic biomarker. Circulating progastrin, hPG80, is a tumor-promoting peptide present in the blood of patients with various cancers that has been shown to have prognostic value. We evaluated the prognostic value of plasma hPG80 in patients with isocitrate dehydrogenase-wild type glioblastoma after surgery.

PATIENTS AND METHODS

A multicentric retrospective study in glioblastoma patients treated with standard radio-chemotherapy was conducted. The hPG80 levels were measured in plasma EDTA samples collected after surgery with an ELISA DxPG80.lab kit (Biodena Care, Montpellier, France), which has a detection threshold of 1.2 pM. The relationship between post-operative hPG80 plasma levels, in combination with other known prognostic factors, and patients' progression-free survival (PFS) and overall survival (OS) was evaluated.

RESULTS

Sixty-nine patients were assessable. Plasma samples were collected after tumor biopsy (B), partial resection (PR), and complete resection (CR) for 22, 25, and 22 patients, respectively. At a median concentration of 5.37 pM (interquartile range 0.00-13.90 pM), hPG80 was detected in 48 (70%) patients (hPG80+). CR was associated with significant lower values of hPG80 levels: the median value was 0.7 versus 9.1 pM for PR (P = 0.02) and 8.3 pM for B (P = 0.004). The hPG80 detection rate was also significantly lower: 50% (CR) versus 72% (PR) versus 86% (B) (P = 0.005). The median follow-up was 39 months [22.4 months-not reached]. hPG80 post-operative detection was associated with numerically shorter PFS (6.4 versus 9.4 months, P = 0.13) and OS (14.5 versus 20.9 months, P = 0.11). In multivariate analysis, hPG80 was a prognostic factor for OS (P = 0.034).

CONCLUSIONS

Circulating hPG80 could serve as a new prognostic biomarker after surgery in patients with glioblastoma treated with radio-chemotherapy.

Mitochondria transfer from tumor-activated stromal cells (TASC) to primary Glioblastoma cells

The tumor microenvironment (TME) controls many aspects of cancer development but little is known about its effect in Glioblastoma (GBM), the main brain tumor in adults. Tumor-activated stromal cell (TASC) population, a component of TME in GBM, was induced in vitro by incubation of MSCs with culture media conditioned by primary cultures of GBM under 3D/organoid conditions. We observed mitochondrial transfer by Tunneling Nanotubes (TNT), extracellular vesicles (EV) and cannibalism from the TASC to GBM and analyzed its effect on both proliferation and survival. We created primary cultures of GBM or TASC in which we have eliminated mitochondrial DNA [Rho 0 (ρ⁰) cells]. We found that TASC, as described in other cancers, increased GBM proliferation and resistance to standard treatments (radiotherapy and chemotherapy). We analyzed the incorporation of purified mitochondria by ρ⁰ and ρ⁺ cells and a derived mathematical model taught us that ρ⁺ cells incorporate more rapidly pure mitochondria than ρ⁰ cells.

Drug resistance in glioblastoma: are persisters the key to therapy?

Glioblastoma (GBM) represents the main form of brain tumors in adults, and one of the most aggressive cancers overall. The treatment of GBM is a combination of surgery (when possible), chemotherapy (usually Temozolomide, TMZ) and radiotherapy (RT). However, despite this heavy treatment, GBM invariably recur and the median length of survival following diagnosis is 12 to 15 months, with less than 10% of people surviving longer than five years. GBM is extremely resistant to most treatments because of its heterogeneous nature, which is associated with extreme clonal plasticity and the presence of cancer stem cells, refractory to TMZ- and RT-induced cell death. In this review, we explore the mechanisms by which cancer cells, and especially GBM, can acquire resistance to treatment. We describe and discuss the concept of persister/tolerant cells that precede and/or accompany the acquisition of resistance. Persister/tolerant cells are cancer cells that are not eliminated by treatment(s) because of different mechanisms ranging from dormancy/quiescence to senescence. We discuss the possibility of targeting these mechanisms in new therapeutic regimen.

Peripheral neck nerve tumor: A 73-case study and literature review

OBJECTIVES

Peripheral neck nerve tumors are rare and mostly benign neoplasms. The exceptional malignant forms are very aggressive, and diagnosis is difficult. The objective of this study was to evaluate diagnostic and therapeutic management and identify possible predictive factors.

MATERIAL AND METHODS

A retrospective study was conducted of 73 patients treated for peripheral neck nerve tumor between 1995 and 2015.

RESULTS

Mean age was 44years. The main presenting symptom was a cervical mass, isolated or associated with signs related to the affected nerve structure. Diagnosis was suspected by slow progression of a firm mass, featuring T1 hyposignal and T2 hypersignal on magnetic resonance imaging. Surgery was performed in 99% of cases, completed by adjuvant chemotherapy in case of malignant neuroblastic tumor. Type 1 neurofibromatosis and sudden increase in mass with or without associated pain suggested malignant transformation. Age below 10years suggested neuroblastic tumor.

CONCLUSION

Neck nerve tumors are very often benign with low degenerative potential. Surgery is the treatment of choice after risk/benefit analysis. However, there is no clearly defined consensus regarding the timing of surgery for these lesions.

Trigeminal Ganglion Metastasis of Renal Clear Cell Carcinoma: Cases Report and Review of the Literature

BACKGROUND

The trigeminal ganglion is an atypical site for metastasis, especially for renal clear cell carcinoma.

CASE DESCRIPTION

We report 2 clinical cases of a 66-year-old man and a 58-year-old man with trigeminal symptoms. Both patients had a history of renal clear cell (RCC) that was considered to be cured at 6 and 9 years, respectively. Brain magnetic resonance imaging (MRI) showed a trigeminal ganglion lesion with increased gadolinium enhancement associated with petrous apex erosion. The main diagnostic hypothesis based on MRI was trigeminal schwannoma for both patients. One patient underwent subtotal removal, the other a biopsy. Histologic examinations resulted in the diagnosis of RCC metastasis. Body computed tomography revealed pancreatic metastasis for both but no renal recurrence. The patients were treated by local radiotherapy, and 1 of the patients had associated chemotherapy. We added to these clinical cases a literature review of skull base metastasis of RCC. Trigeminal ganglion metastasis of RCC is very rare and can persist until 10 years after the first RCC diagnosis. It seems that the best treatment is surgical removal. To date, the role of local radiotherapy is not demonstrated, and the prognosis seems to be poor.

CONCLUSIONS

In the case of trigeminal symptoms, rapid tumoral growth on brain MRI, or a history of RCC, we think that a body computed tomography should be performed, and surgery should be considered.

Extrinsic and intrinsic blood supply to the optic chiasm

Although there have been many studies of the arterial cerebral blood supply, only seven have described the optic chiasm (OC) blood supply and their results are contradictory. The aim of this study was to analyze the extrinsic and intrinsic OC blood supply on cadaveric specimens using dissections and microcomputer tomography (Micro-CT). Thirteen human specimens were dissected and the internal or common carotid arteries were injected with red latex, China Ink with gelatin or barium sulfate. Three Micro-CTs were obtained to reveal the intrinsic blood supply to the OC. The superior hypophyseal arteries (SupHypA) (13/13) and posterior communicating artery (PCoA) (12/13) supplied the pial network on the inferior side of the OC. The first segment of the anterior cerebral artery (ACA) (10/10), SupHypA (7/10), the anterior communicating artery (ACoA) (9/10), and PComA (1/10) supplied the pial network of its superior side. The intrinsic OC blood supply was divided into three networks (two lateral and one central). Capillaries entering the OC originated principally from the inferior pial network. The lateral network capillaries had the same orientation as the visual lateral pathways, but the central network was not correlated with the nasal fibers crossing into the OC. There was no anastomosis in the pial or intrinsic networks. Only SupHypA, PCoA, ACoA, and ACA were involved in the OC blood supply. Because there was no extrinsic or intrinsic anastomosis, all arteries should be preserved. Tumor compression of the inferior intrinsic arterial network could contribute to visual defects. Clin. Anat. 31:432-440, 2018. © 2017 Wiley Periodicals, Inc.

PDGF activation in PGDS-positive arachnoid cells induces meningioma formation in mice promoting tumor progression in combination with Nf2 and Cdkn2ab loss

The role of PDGF-B and its receptor in meningeal tumorigenesis is not clear. We investigated the role of PDGF-B in mouse meningioma development by generating autocrine stimulation of the arachnoid through the platelet-derived growth factor receptor (PDGFR) using the RCAStv-a system. To specifically target arachnoid cells, the cells of origin of meningioma, we generated the PGDStv-a mouse (Prostaglandin D synthase). Forced expression of PDGF-B in arachnoid cells in vivo induced the formation of Grade I meningiomas in 27% of mice by 8 months of age. In vitro, PDGF-B overexpression in PGDS-positive arachnoid cells lead to increased proliferation.We found a correlation of PDGFR-B expression and NF2 inactivation in a cohort of human meningiomas, and we showed that, in mice, Nf2 loss and PDGF over-expression in arachnoid cells induced meningioma malignant transformation, with 40% of Grade II meningiomas. In these mice, additional loss of Cdkn2ab resulted in a higher incidence of malignant meningiomas with 60% of Grade II and 30% of Grade III meningiomas. These data suggest that chronic autocrine PDGF signaling can promote proliferation of arachnoid cells and is potentially sufficient to induce meningiomagenesis. Loss of Nf2 and Cdkn2ab have synergistic effects with PDGF-B overexpression promoting meningioma malignant transformation.

Management of aneurysmal subarachnoid haemorrhage with intracerebral hematoma: Is there an indication for coiling first? Study of 44 cases

BACKGROUND

Aneurysmal subarachnoid haemorrhage (ASH) with intracerebral hematoma (ICH) has a poor prognosis. The treatment is to secure the aneurysm and do an ICH evacuation.

OBJECTIVE

The aim of the study was to determine if aneurysm coiling followed by ICH evacuation is a viable alternative treatment compared to exclusive surgery, regardless of the clinical or paraclinical presentations.

METHODS

A retrospective study was conducted between 2004 and 2014, which included 44 patients. The patients were divided up in four groups. Two were principal groups: The clipped group (aneurysm clipping with ICH evacuation) and the coiled group (aneurysm coiling, followed by ICH evacuation); and two were subgroups of the latter: Aneurysm coiling with ICH evacuation after 24 hours and ICH evacuation followed by aneurysm coiling. We studied the demographic and radiologic characteristics, and the 3-month outcome.

RESULTS

We included 17 patients in the coiled group: The outcome was better for the patients with World Federation of Neurosurgery (WFNS) scores of 1, 2 and 3; compared to the patients with WFNS scores 4 and 5. We included 16 patients in the clipped group: The outcome was better, compared the coiled group, for those patients with WFNS scores 4 and 5. Six patients were treated with aneurysm coiling, followed by ICH evacuation after 24 hours: 33% had a good outcome. Five patients were treated by ICH evacuation, followed by aneurysm coiling: None had a good outcome.

CONCLUSIONS

It was necessary to realise a prospective study to compare the outcomes of patients with WFNS scores of 1, 2 or 3; between those with aneurysm coiling followed by ICH evacuation and aneurysm clipping with ICH evacuation, to determine the potential of using the coiling first, for these patients.

[Familial colloid cyst of the third ventricle: case report and review of the literature]

Colloid cysts of the third ventricle are rare benign lesions. We report here an exceptional familial case defined by the evidence of two colloid cysts in two relatives of the first degree, a mother and her daughter in our description. Only 15 cases are reported in the literature. The main differences compared with sporadic cases are an earlier age of discovery and a female predominance. In case of familial colloid cyst, we have to recover a brain MRI screening of all the relatives of the first degree.