Miglioramento delle proprietà meccaniche di alcune argille naturali per diffusione di sali nel fluido interstiziale

Analogamente a quanto già osservato per argille pure ad elevatissima plasticità (Na-montmorillonite), il comportamento meccanico di alcune argille naturali (le argille di Bisaccia, Gela, Milazzo, della frana Marino) ricostituite in laboratorio è risultato estremamente influenzato dall'esposizione a soluzioni di cloruro di sodio o di potassio. Si sono infatti verificati notevoli incrementi di resistenza a taglio e riduzioni di deformabilità, anche nelle argille la cui plasticità valutata in modo convenzionale è molto inferiore a quella della montmorillonite. In funzione del tipo di elettrolita utilizzato, tale miglioramento si è rivelato reversibile (NaCl) o irreversibile (KCl). Questi risultati, oltre a chiarire alcuni aspetti del comportamento meccanico dei materiali analizzati, configurano il trattamento chimico come intervento di miglioramento dei terreni molto interessante sia per entità che per durata

Residual strength of kaolin and bentonite: the influence of their constituent pore fluid

The residual strength of clays is affected by their mineral composition and by the nature of their constituent pore fluid. In principle, both factors may influence either strength parameters or stresses, but it is not yet completely clear how this influence works. Previous publications have elucidated some aspects of clay residual strength behaviour. This Paper investigates further the roles of minerals and pore fluid composition on the residual strength of clayey soils. It describes and analyses tests on kaolin, bentonite and their mixtures exposed to distilled water and sodium choride solutions with given concentrations. The results show that the shear strength of kaolin is not affected by the solutions used, whereas the residual strength of bentonite varies greatly because of the inward salt diffusion towards the clay. Further, for the clay mixtures with any of the pore fluids considered, the weaker component has the greater influence on the behaviour of the mixture

La rabbia nel mantenimento del legame affettivo

Questo breve intervento vuole mettere in evidenza alcuni processi osservabili nei legami conflittuali in cui lo “stare insieme” ed il “separarsi “ appaiono due poli tra cui la coppia oscilla nel mantenimento della relazione. Il litigio può sfociare in episodi di violenza ove la rabbia espressa invece che portare alla rottura del legame ne determina il mantenimento. L’osservazione di questi processi necessita nel professionista l’assunzione di una posizione terza in modo tale da poter cogliere non la responsabilità o la colpa dei contendenti ma “in che modo” essi stessi partecipano alla creazione e mantenimento della transazione

Intracranial Hemorrhage After Endovascular Repair of Thoracoabdominal Aortic Aneurysm

Background: Intracranial hemorrhage (ICH) is a rare but devastating complication of thoracoabdominal aortic aneurysm (TAAA) repair with fenestrated/branched endograft (f/bEVAR). The cerebrospinal fluid drainage (CSFD) is considered one of the leading causes; however, other possible concomitant factors have not been individualized yet. The aim of the present work was to evaluate the pattern of ICH events after f/bEVAR for TAAA and to identify possible associated factors. Materials and Methods: All f/bEVAR procedures for TAAA performed in a single academic center from 2012 to 2020 were evaluated. ICH was assessed by cerebral computed tomography if neurological symptoms arose. Pre-, intra-, and postoperative characteristics were analyzed in order to identify possible factors associated. Results: A total of 135 f/bEVAR were performed for 72 (53%) type I, II, III and 63 (47%) type IV TAAA; 74 (55%) were staged procedures, 101 (73%) required CSFD, and 24 (18%) were performed urgently. The overall 30-day mortality was 8% (5% in elective cases); spinal-cord ischemia occurred in 11(8%) and ICH in 8 (6%) patients. All ICH occurred in patients with CSFD. ICH occurred intraoperatively in 1 case, inter-stage in 4 and after F/BEVAR completion in 3, after a median of 6 days the completion stage. Three (38%) of 8 patients with ICH died at 30 days and ICH was associated with 30-day mortality: odds ratio (OR) 13.2, 95% confidence interval (CI): 2.3–76, p=0.01. The analysis of the perioperative characteristics identified platelet reduction >60% (OR 11, 95% CI 1.6–77, p=0.03), chronic kidney disease (16% vs 0%, p=0.002), and total volume of liquor drained >50 mL (OR 8.1, 95% CI 1.1–69, p=0.03) as associated with ICH. Conclusions: Current findings may suggest that ICH is a potential lethal complication of the endovascular treatment for TAAAs and it mainly occurs in patients with CSFD. High-volume liquor drainage, platelet reduction, and chronic kidney disease seems increase significantly the risk of ICH and should be considered during the perioperative period and for further studies

Cervical artery dissection: presentation and treatment

Cervical artery dissection (CeAD) is a rare condition whereby a tear occurs in the intimal layer of the artery wall. This condition can determine stroke, peripheral symptoms or can be asymptomatic. Vascular surgeons are often involved in the treatment of this pathology and the present paper aims to overview the actual knowledge on this topic. Clinical studies and randomized trials were screened and analyzed through PubMed to report the incidence, the clinical manifestations and the treatment options of CeAD. CeAD involving extracranial internal carotid artery is most frequently involved (80%) rather than vertebral artery (15%) or carotid artery in association with vertebral artery (5%). Internal carotid dissection occurs in all age group and it is responsible for 2.5% of all strokes, and 40% of stroke in patients older than 50 years. Carotid artery dissection typically begins with local symptoms, such as a sudden onset of unilateral and constant headache or an ipsilateral neck pain or a partial Horner’s syndrome, followed by retinal or cerebral ischemia. Stroke associated with CeAD are present in 50-60% of symptomatic cases, even if many of CeAD are asymptomatic and therefore the real incidence of stroke associated with CeAD is difficult to establish. The risk of recurrent stroke after carotid artery dissection is less than 3%. Anticoagulant or antiplatelet therapy are both associated with low-rate of symptoms recurrence (1-3%) at the follow-up. Surgical or endovascular therapy can be considered for patients with symptoms recurrence without benefit from medical therapy. CeAD is a possible cause of stroke, and it should be carefully investigated, particularly in young patients, in order to deliver an adequate therapeutic approach

Tailored Sac Embolization During EVAR for Preventing Persistent Type II Endoleak

Background: Persistent type II endoleaks (ELIIp) occur in 8–23% of patients submitted to endovascular aneurysm repair (EVAR) and may lead to aneurysm progression and rupture. Intraoperative embolization of the abdominal aortic aneurysm (AAA) sac is effective to prevent their occurrence, however a method to achieve complete sac thrombosis has not been standardized yet. Aim of our study was to identify factors associated with prevention of ELIIp after intraoperative embolization, in order to optimize technical details. Methods: Patients at high risk for ELIIp, who underwent EVAR with AAA - sac coil embolization were prospectively collected into a dedicated database from January 2012 to March 2015. The endoluminal residual sac volume (ERV), not occupied by the endograft [ERV= AAA total volume (TV) – (AAA-thrombus volume (THV) + endograft volume (EgV)] was calculated on preoperative computed tomography and the concentration of coils implanted (CCoil= n coils implanted/ERV) for each patient was evaluated. AAA volumetric evaluation was conducted by dedicated vessels analysis software (3Mensio). ELIIp presence was evaluated by contrast-enhanced ultrasound at 6 and 12-month. Patients with ELIIp at 12 months (Group 1) were clustered and compared to patients without ELIIp (Group 2), in order to evaluate the incidence of ELIIp in patients undergone to preventive AAA-sac embolization, and identify the predictors of ELIIp prevention. Morphological potential risk factors for ELIIp such as TV, THV, VR% and EgV were also considered in all patients. Statistical correlation was assessed by Fisher Exact Test. Results: Among 326 patients undergone to standard EVAR, 61 (19% - M: 96.7%, median age: 72 [IQR: 8] years, median AAA diameter: 57 [IQR: 7] mm) were considered at high risk for ELIIp and were submitted to coil embolization. The median AAA total volume (TV) and median ERV were 156 (IQR: 59) cc and 46 (IQR: 26) cc, respectively. The median number and concentration of coils (IMWCE-38-16-45 Cook M-Ray) positioned in AAA-sac were 5 (IQR: 1) coils and 0.17 coil/cm3 (range 0.02-1.20). Among this high-risk population, the incidence of ELIIp was 29.5% and 23% at 6 and 12-month, respectively. Fourteen patients (23%) were clustered in Group1 and 47 (77%) in Group 2. Both groups were homogeneous for clinical characteristics and preoperative morphological risk factors. There were no differences in the preoperative median TV, AAA-thrombus volume (THV), %VR, EgV and number of implanted coils between Group1 and Group2. Patients in Group1 had a significantly higher ERV (59 [IQR: 13] cm3 vs. 42 [IQR: 27] cm3, P = 0.002) and lower CCoil (0.09 [IQR: 0.03] vs. 0.18 [IQR: 0.21], P = 0.006) than patients of Group2. ELIIp was significantly related to the presence of ERV > 49 cm3 (86 % vs. 42 %, Group1 and Group2 respectively, P = 0.006) and CCoil < 0.17coil/ cm3 (100% vs. 68%, Group1 e Group2 respectively, P = 0.014). Conclusion: According with our results, Coil concentration and endoluminal residual volume can affect the efficacy of the AAA – sac embolization in the prevention of ELIIp, moreover CCoil ≥0.17coil/ cm3 maight be considered to determine the tailored number of coils