Embryological development of the human cranio-facial arterial system: a pictorial review.

The embryological development of the cerebral vasculature is very complex. Historical and also more recent studies based on human embryos, comparative anatomy and cerebral angiographies allowed us to better understand this vasculature development. The knowledge and understanding of such embryological development are important for physicians interested in neurovascular pathologies. Indeed, all vascular variants and almost all vascular pathologies, such as aneurysms, dolichoectasia, atherosclerosis, and neurovascular conflicts could be explained by an alteration during the embryological life. There are also many variants of these vascular structures present in normal developed adults, which are variably associated with pathological entities. Understanding the process which leads to the development of the normal cerebral arterial system in humans is, therefore, very important to have a better knowledge of the possible clinical and surgical implications of these anomalies. In this paper, we review the embryological development of the cranio-facial arterial vasculature from its beginning at approximately days 21-50 of intrauterine life, with pictures illustrating each developmental phase.

Rare neurovascular conflict between oculomotor nerve and posterior communicating artery.

Paroxysmal diplopia could be the expression of a multitude of clinical or anatomical conditions. Both ophthalmological and neurological pathologies could be responsible of this symptom. Rarely, a neurovascular conflict involving the oculomotor nerve is the etiology. We present the case of a 75-year-old man who presented for a 20-year history of transient vertical diplopia. The radiological exams demonstrated the presence of a neurovascular conflict between the right oculomotor nerve and a fetal-type posterior communicating artery. This fetal posterior communicating artery had an aberrant downward course that compressed the third cranial nerve. Few cases of neurovascular conflict interesting the third cranial nerve were described in the literature whom the responsible artery was generally the superior cerebellar artery. No case of oculomotor nerve compression by the posterior communicating artery was published. Authors have reviewed the literature and discuss the embryology of the posterior communicating artery, pathophysiology, radiological findings, and therapeutic possibility.

Third nerve decompression by anterior petroclinoid ligament opening after clipping of posterior communicating artery aneurysm-How I do it.

BACKGROUND: Posterior communicating artery aneurysms sometimes present with partial or complete oculomotor nerve palsy, due to direct oculomotor nerve compression, irritation by subarachnoid blood, or both. Superiority of surgical clipping over endovascular coiling in terms of postoperative outcome is still controversial. METHOD: Direct oculomotor nerve decompression by opening of the anterior petroclinoid ligament during aneurysm clipping is performed as a simple and feasible surgical maneuver which allows to improve the decompression effect obtained by aneurysm exclusion. CONCLUSION: Anterior petroclinoid ligament opening permits to achieve a better oculomotor nerve decompression. Its efficiency on the recovery of the deficit needs to be proved by larger series.

'Armed kyphoplasty' with posterior stabilization avoids corpectomy in complex thoracolumbar spine fractures: a case series.

BACKGROUND: Complex thoracolumbar fractures require reduction and stabilization. Posterior instrumentation alone and standard cement augmentation may represent undertreatment, while corpectomy has significant morbidity. In a series of unstable thoracolumbar fractures, we assessed the feasibility, safety, and results of 'armed kyphoplasty' (AKP) and surgical posterior stabilization (PS). METHODS: A total of 24 consecutive patients were treated with combined AKP and PS. Minimally invasive and open surgery techniques were used for PS. AKP was performed with C-arm or biplane fluoroscopic guidance, and screws were placed under navigation or fluoroscopic guidance. A postoperative CT scan and standing plain films were obtained. Patients were followed up according to clinical standards. Kyphosis correction (measured with regional Cobb angle), pain (measured with the Numeric Rating Scale), neurological status (measured with Frankel grade) were assessed. RESULTS: A total of 25 fractures of neoplastic (40%), traumatic (32%), and osteoporotic (28%) nature were treated. Open surgery and minimally invasive techniques were applied in 16/24 and 8/24 patients, respectively. Decompressive laminectomy was performed in 13 cases. No intraprocedural complications occurred. Two patients (8%) died due to underlying disease complications and three complications (12%) required re-intervention (one surgical site infection, one adjacent fracture, and one screw pull-out) in the first month. The mean Cobb angle was 20.14±6.19° before treatment and 11.66±5.24° after treatment (P<0.0001). No re-fractures occurred at the treated levels. CONCLUSIONS: Combined AKP and PS is feasible and effective in the treatment of complex thoracolumbar fractures of all etiologies. AKP avoided highly invasive corpectomy. Anterior and posterior support ensured stability, preventing implant failure and re-fracture. The complication rate was low compared with more invasive traditional 360° open surgical approaches.

Optic Radiation Diffusion Tensor Imaging Tractography: An Alternative and Simple Technique for the Accurate Detection of Meyer's Loop.

BACKGROUND: The optic radiation (OR) is a white matter bundle with a very complex anatomy. Its anterior component bends sharply around the tip of the temporal horn, forming the Meyer's loop (ML), the sparing of which during surgery is crucial to preserve visual function. Defining its exact anatomy and accurately identifying its position remain challenging, even with diffusion tensor imaging (DTI) tractography and the most refined tracking procedure. We have developed an alternative tracking technique to detect the ML position. METHODS: We performed DTI studies in 26 patients undergoing resection of a temporo-parieto-occipital lesion. We then reconstructed the ORs of each patient using 2 techniques (the first developed by our team, the other taken from the literature), using the same tracking software and parameters. We evaluated the accuracy of each technique measuring 3 distances that define the ML position. We created 5 data groups and compared the 2 techniques. Finally, we compared our results with the results from 8 anatomic dissection studies and other tractographic studies. RESULTS: Our findings show that our technique allows a more accurate definition of the ML position. We found a statistically significant (P < 0.05) difference for all the distances between the 2 techniques; our results resemble those obtained in dissection studies. Our technique is also easy to perform and repeatable. CONCLUSIONS: Our tracking technique may be of marked interest for the evaluation and anatomic definition of the ML position, particularly for neurosurgeons approaching the anterior temporal region.

Long-Standing Isolated Autoimmune Hypothalamitis Diagnosed with Endoscopic Transventricular Biopsy.

BACKGROUND: Autoimmune hypothalamitis, which is among the causes of acquired central diabetes insipidus, has seldom been described in the literature. This condition is probably provoked by the production of anti-vasopressin-secreting cell antibodies and antihypothalamus antibodies and is often associated with pituitary or polyendocrine autoimmunity. Correct diagnosis and immediate treatment are essential to avoid the progression of the pathologic process. CASE DESCRIPTION: A woman diagnosed with central diabetes insipidus 12 years ago, who had panhypopituitarism and mild memory deficit, came to our attention. She refused radiologic studies. Magnetic resonance imaging performed in our unit showed a contrast-enhancing hypothalamic lesion. Lumbar puncture was negative for neoplastic markers. We decided to perform a biopsy of the lesion to obtain a histopathologic examination of the tissue and chose an endoscopic transventricular approach to reach the floor of the third ventricle. Autoimmune hypothalamitis was diagnosed and treatment with steroids and azathioprine was started. The lesion size decreased and was stable after 17 months of follow-up. CONCLUSIONS: The endoscopic transventricular approach has proved to be an effective and safe way to obtain tissue samples for histopathologic examination from a region that is usually difficult to reach; it also gives direct visualization of the lesion, which makes sampling easier. The lesion size decreased after treatment but no clinical improvement was detected, either on the cognitive or on the endocrinologic side.