Strategies for Optic Pathways Decompression for Extra-Axial Tumors or Intracranial Aneurysms: A Technical Note

Abstract Background Different types of skull base tumors and intracranial aneurysms may lead to compression of the optic pathways. Since most of them are biologically benign conditions, the first aim of surgery is preservation of optic nerves rather than the oncologic radicality. Materials and methods Based on the progressive technical refinements coming from our institutional experience of optic nerve compression from aneurysms and extra-axial tumors, we analyzed the surgical steps to release nerves and chiasm during tumor debulking and aneurysm clipping. Results We distinguished vascular and tumor lesions according to the main direction of optic nerve compression: lateral to medial, medial to lateral, inferior to superior, and anterior to posterior. We also identified four fundamental sequential maneuvers to release the optic nerve, which are (1) falciform ligament (FL) section, (2) optic canal unroofing, (3) anterior clinoid process drilling, and (4) optic strut removal. The FL section is always recommended when a gentle manipulation of the optic nerve is required. Optic canal unroofing is suggested in case of lateral-to-medial compression (i.e., clinoid meningiomas), medial-to-lateral compression (i.e., tuberculum sellae meningiomas), and inferior-to-superior compression (i.e., suprasellar lesions). Anterior clinoidectomy and optic strut removal may be necessary in case of lateral-to-medial compression from paraclinoid aneurysms or meningiomas. Conclusions Preservation of the visual function is the main goal of surgery for tumors and aneurysms causing optic nerve compression. This mandatory principle guides the approach, the timing, and the technical strategy to release the optic nerve, and is principally based on the direction of the compression vector

Arrhythmias and hemodialysis: role of potassium and new diagnostic tools.

Cardiovascular diseases represent the main causes of death in patients affected by renal failure, and arrhythmias are frequently observed in patients undergoing hemodialysis. Dialytic treatment per se can be considered as an arrhythmogenic stimulus; moreover, uraemic patients are characterized by a "pro-arrhythmic substrate" because of the high prevalence of ischaemic heart disease, left ventricular hypertrophy and autonomic neuropathy. One of the most important pathogenetic element involved in the onset of intra-dialytic arrhythmias is the alteration in electrolytes concentration, particularly calcium and potassium. It may be very useful to monitor the patient's cardiac activity during the whole hemodilaytic session. Nevertheless, the application of an extended intradialytic electrocardiographic monitoring is not simple because of several technical and structural impairments. We tried to overcome these difficulties using Whealthy, a wearable system consisting in a t-shirt composed of conductors and piezoresistive materials, integrated to form fibers and threads connected to tissutal sensors, electrodes, and connectors. ECG and pneumographic impedance signals are acquired by the electrodes in the tissue, and the data are registered by a small computer and transmitted via GPRS or Bluetooth

Pulmonary Hypertension and Erythropoietin

Numerous uremic patients on hemodialysis have pulmonary hypertension attributable to the presence of arteriovenous fistulas, vascular calcification, and endothelial dysfunction due to alterations in the balance between vasoconstrictive and vasodilatory substances. For these reasons, the effects of recombinant human erythropoietin, a drug widely used in patients on dialysis, on the pulmonary circulation were studied. Some authors maintain that recombinant human erythropoietin has an antihypertensive effect, while others have observed that this hormone induces a reduction in pulmonary arterial pressure due to its vasoactive and stimulatory effects on endothelial and smooth muscle cell precursors

A workflow to generate physical 3D models of cerebral aneurysms applying open source freeware for CAD modeling and 3D printing

Objectives: 3D anatomical models are becoming a new frontier in surgery for planning and simulation on an individualized patient specific basis. Since 1999, 3D cerebral aneurysms models for neurosurgery have been proposed. The possibility of reproducing in a realistic 3D fashion the malformation with the surrounding vascular structures, provides important preoperative information for the treatment strategy. The same models can be used for training and teaching.Unfortunately stereolitography is often burdened by high costs and long times of production. These factors limit the possibility to use 3D models to plan surgeries in an easy daily fashion. Patients and methods: Our study enrolled 5 patients harboring cerebral aneurysms. DICOM data of each aneurysm were elaborated by an open source freeware to obtain CAD molds. Afterwards, the 3D models were produced using a fused deposition or a stereolitography printer. Results: Models were evaluated by Neurosurgeons in terms of quality and usefulness for surgical planning. Costs and times of production were recorded. Conclusions: Models were reliable, economically affordable and quick to produce. Keywords: Stereolitography, Cerebral aneurysms, 3D printing, Surgical planning, Aneurysm model

Bleeding risk evaluation in cerebral cavernous malformation, the role of medications, and hemorrhagic factors: a case-control study

Objective: Cerebral cavernous malformations (CCMs) are vascular lesions with an overall risk of rupture from 2% to 6% per year, which is associated with significant morbidity and mortality. The diagnostic incidence is increasing, so it is of paramount importance to stratify patients based on their risk of rupture. Data in the literature seem to suggest that specific medications, particularly antithrombotic and cardiovascular agents, are associated with a reduced risk of bleeding. However, the effect of the patient coagulative status on the cumulative bleeding risk remains unclear. The aim of this study was to assess the impact of different radiological, clinical, and pharmacological factors on the bleeding risk of CCMs and to assess the predictive power of an already validated scale for general bleeding risk, the HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol concomitantly). Method: This was a multicenter retrospective observational study. The authors collected imaging, clinical status, and therapy data on patients with bleeding and nonbleeding CCMs. Univariate analysis and subsequent multivariate logistic regression were performed between the considered variables and bleeding or nonbleeding status to identify potential independent predictors of bleeding. Results: The authors collected data on 257 patients (46.7% male, 25.3% with bleeding CCMs). Compared with patients with nonbleeding lesions, those with bleeding CCMs were younger, less frequently had hypertension, and less frequently required antiplatelet drugs and beta-blockers (all p < 0.05). Bleeding lesions, however, had significantly higher median volumes (1050 mm3 vs 523 mm3 , p < 0.001). On multivariate analyses, after adjusting for age, history of hypertension and diabetes, and use of antiplatelet drugs or beta-blockers, lesion volume ≥ 300 mm3 was the only significant predictor of bleeding (adjusted OR 3.11, 95% CI 1.09-8.86). When the diagnostic accuracy of different volume thresholds was explored, volume ≥ 300 mm3 showed a limited sensitivity (36.7%, 95% CI 24.6%-50.0%), but a high specificity 78.2% (95% CI 71.3%-84.2%), with an area under the curve of 0.57 (95% CI 0.51-0.64). Conclusions: This study supports previous findings that the CCM volume is the only factor influencing the bleeding risk. Antithrombotic agents and propranolol seem to have a protective role against the bleeding events. A high HAS-BLED score was not associated with an increased bleeding risk. Further studies are needed to confirm these results

Comparison between intrasylvian and intracerebral hematoma associated with ruptured middle cerebral artery aneurysms: clinical implications, technical considerations, and outcome evaluation

Background: Subarachnoid hemorrhage (SAH) due to a middle cerebral artery (MCA) aneurysms rupture is often associated with intracerebral (ICH) or intrasylvian hematomas (ISH). Materials and methods: We reviewed 163 patients with ruptured MCA aneurysms associated with pure SAH or SAH+ICH/ISH. Patients were first dichotomized according to the presence of a hematoma (ICH/ISH). Then, we performed a subgroup analysis comparing ICH versus ISH in order to explore their relationship with the most relevant demographic, clinical, and angioarchitectural features. Results: Overall, 85 patients (52%) had a pure SAH, whereas 78 (48%) presented an associated ICH/ISH. No significant differences were observed in demographics and angioarchitectural features between the two groups, but Fisher grading and Hunt-Hess score were higher in patients with hematomas. A good outcome was observed in a higher percentage of patients with pure SAH compared with the others (76% Vs 44%), although mortality rates were comparable. Age, Hunt-Hess and treatment-related complications were the main outcome predictors at multivariate analysis. Patients with ICH appeared clinically worse than those with ISH. We also found that older age, higher Hunt-Hess, larger aneurysms, decompressive craniectomy and treatment-related complications were associated with poor outcome among patients with ISH, but not with ICH, which appeared per se as a more severe clinical condition. Conclusions: Our study confirm that age, Hunt-Hess and treatment-related complications influence the outcome of patients with ruptured MCA aneurysms. However, in the subgroup analysis of patients with SAH associated with ICH or ISH, only the Hunt-Hess at onset appeared as an independent predictor of outcome

recombinant human erythropoietin influences revascularization and healing in a rat model of random ischaemic flaps

In order to ascertain whether erythropoietin plays a role in early and late repair processes following ischaemic skin flap injury, a dorsal, caudally based skin flap was created in rats. The rats were successively divided into four groups. Group 1 was not treated. The other groups were treated with a subcutaneous administration of 0.9% NaCl saline solution (group 2), a subcutaneous administration of vehicle (group 3) or a subcutaneous administration of 300 IU/kg/day of recombinant human erythropoietin (group 4). We evaluated the possible relationships between neutrophil accumulation, myeloperoxidase activity and content in flap tissue, flap survival, flap temperature (using telethermography) and flap revascularization (using videocapillaroscopy). Necrosis in the flap was significantly less extensive in group 4 than in groups 1, 2 and 3. A significant increase in neutrophil infiltration occurred between the 1st and 24th hour in these groups, but this was not observed in group 4. These findings were confirmed by biochemical data of myeloperoxidase activity and malonyldialdehyde content. Between the 1st and 7th days, we recorded an increase of about 20% in flap temperature in groups 1, 2 and 3, whereas no significant variation was observed in group 4. On the 7th day, videocapillaroscopic findings showed an increase in the mean vascularization index in group 4. Our findings suggest that recombinant human erythropoietin administration can improve the wound healing process, in both early and late stages of injury, by reducing inflammatory response, increasing the density of capillaries in ischaemic flaps and allowing earlier repair of a damaged area

From Nutcracker Phenomenon to Nutcracker Syndrome: A Pictorial Review

Left renal vein (LRV) entrapment, also known as nutcracker phenomenon if it is asymptomatic, is characterized by abnormality of outflow from the LRV into the inferior vena cava (IVC) due to extrinsic LRV compression, often accompanied by demonstrable lateral (hilar) dilatation and medial (mesoaortic) stenosis. Nutcracker syndrome, on the other hand, includes a well-defined set of symptoms, and the severity of these clinical manifestations is related to the severity of anatomic and hemodynamic findings. With the aim of providing practical guidance for nephrologists and radiologists, we performed a review of the literature through the PubMed database, and we commented on the definition, the main clinical features, and imaging pattern of this syndrome; we also researched the main therapeutic approaches validated in the literature. Finally, from the electronic database of our institute, we have selected some characteristic cases and we have commented on the imaging pattern of this disease

From Nutcracker Phenomenon to Nutcracker Syndrome: A Pictorial Review

Left renal vein (LRV) entrapment, also known as nutcracker phenomenon if it is asymptomatic, is characterized by abnormality of outflow from the LRV into the inferior vena cava (IVC) due to extrinsic LRV compression, often accompanied by demonstrable lateral (hilar) dilatation and medial (mesoaortic) stenosis. Nutcracker syndrome, on the other hand, includes a well-defined set of symptoms, and the severity of these clinical manifestations is related to the severity of anatomic and hemodynamic findings. With the aim of providing practical guidance for nephrologists and radiologists, we performed a review of the literature through the PubMed database, and we commented on the definition, the main clinical features, and imaging pattern of this syndrome; we also researched the main therapeutic approaches validated in the literature. Finally, from the electronic database of our institute, we have selected some characteristic cases and we have commented on the imaging pattern of this disease