Factors affecting formation and rupture of intracranial saccular aneurysms.

Unruptured intracranial aneurysms represent a decisional challenge. Treatment risks have to be balanced against an unknown probability of rupture. A better understanding of the physiopathology is the basis for a better prediction of the natural history of an individual patient. Knowledge about the possible determining factors arises from a careful comparison between ruptured versus unruptured aneurysms and from the prospective observation and analysis of unbiased series with untreated, unruptured aneurysms. The key point is the correct identification of the determining variables for the fate of a specific aneurysm in a given individual. Thus, the increased knowledge of mechanisms of formation and eventual rupture of aneurysms should provide significant clues to the identification of rupture-prone aneurysms. Factors like structural vessel wall defects, local hemodynamic stress determined also by peculiar geometric configurations, and inflammation as trigger of a wall remodeling are crucial. In this sense the study of genetic modifiers of inflammatory responses together with the computational study of the vessel tree might contribute to identify aneurysms prone to rupture. The aim of this article is to underline the value of a unifying hypothesis that merges the role of geometry, with that of hemodynamics and of genetics as concerns vessel wall structure and inflammatory pathways.

Validation of an open source framework for the simulation of blood flow in rigid and deformable vessels.

We discuss in this paper the validation of an open source framework for the solution of problems arising in hemodynamics. The proposed framework is assessed through experimental data for fluid flow in an idealized medical device with rigid boundaries and a numerical benchmark for flow in compliant vessels. The core of the framework is an open source parallel finite element library that features several algorithms to solve both fluid and fluid-structure interaction problems. The numerical results for the flow in the idealized medical device (consisting of a conical convergent, a narrow throat, and a sudden expansion) are in good quantitative agreement with the measured axial components of the velocity and pressures for three different flow rates corresponding to laminar, transitional, and turbulent regimes. We emphasize the crucial role played by the accuracy in performing numerical integration, mesh, and time step to match the measurements. The numerical fluid-structure interaction benchmark deals with the propagation of a pressure wave in a fluid-filled elastic tube. The computed pressure wave speed and frequency of oscillations, and the axial velocity of the fluid on the tube axis are close to the values predicted by the analytical solution associated with the benchmark. A detailed account of the methods used for both benchmarks is provided.

Computational models to predict stenosis growth in carotid arteries: which is the role of boundary conditions?

This work addresses the problem of prescribing proper boundary conditions at the artificial boundaries that separate the vascular district from the remaining part of the circulatory system. A multiscale (MS) approach is used where the Navier-Stokes equations for the district of interest are coupled to a non-linear system of ordinary differential equations which describe the circulatory system. This technique is applied to three 3D models of a carotid bifurcation with increasing stenosis resembling three phases of a plaque growth. The results of the MS simulations are compared to those obtained by two stand-alone models. The MS shows a great flexibility in numerically predicting the haemodynamic changes due to the presence of a stenosis. Nonetheless, the results are not significantly different from a stand-alone approach where flows derived by the MS without stenosis are imposed. This is a consequence of the dominant role played by the outside districts with respect to the stenosis resistance.

Obese teenagers treated by Lap-Band System: the Italian experience.

BACKGROUND: Little is known about obesity surgery in young and adolescent patients. The aim of this study is to evaluate results of laparoscopic adjustable gastric banding in obese teenagers. METHODS: Patients < or = 19 years old selected from the database of the Italian Collaborative Study Group for Lap-Band were analyzed according to mortality, comorbidities, laparotomic conversion, intra- and postoperative complications, body mass index (BMI), and % excess weight loss (EWL) at different times of follow-up. Data were expressed as mean +/- SD. RESULTS: Fifty-eight (1.5%) of 3813 patients who underwent operation with the Lap-Band System were < or = 19 years old: 47F/11M; mean age, 17.96 +/- 0.99 years (range, 15-19); mean BMI, 46.1 +/- 6.31 Kg/m2 (range, 34.9 - 69.25); mean % excess weight, 86.4 +/- 27.1 (range, 34 - 226.53). Sixteen (27.5%) of the 58 patients were superobese (BMI > or = 50). In 27/58 (46.5%) patients, 1 or more comorbidities were diagnosed. Mortality was absent. Laparotomic conversion was necessary in 1 patient with gastric perforation on the anterior wall. Overall postoperative complications occurred in 6/58 (10.3%). The band was removed in 6/58 (10.3%) patients for gastric erosion (3 patients), psychologic, intolerance (2 patients), and in the remaining patient was converted 2 years after surgery (BMI 31) to gastric bypass or gastric pouch dilatation. Patient follow-up at 1, 3, 5, and 7 years was 48/52 (92.3%), 37/42 (88.1%), 25/33 (75.7%), and 10/10, respectively. At these times, mean BMI was 35.9 +/- 8.4, 37.8 +/- 11.27, 34.9 +/- 12.2, and 29.7 +/- 5.2 Kg/m2. Mean %EWL at the same time was 45.6 +/- 29.6, 39.7 +/- 29.8, 43.7 +/- 38.1, and 55.6 +/- 29.2. Five/25 (20%) patients had < or = 25% EWL at 5 years follow-up, while none of the 10 patients subject to follow-up at 7 years had < or = 25% EWL. CONCLUSIONS: Lap-Band System is an interesting option for teenagers suffering obesity and its related comorbidities, which deserves further investigation.

Transient increase of plasma ghrelin after laparoscopic adjustable gastric banding in morbid obesity.

Ghrelin is a peptide hormone with orexigenic properties that is produced by the stomach. Ghrelin and leptin are thought to be the main regulators of appetite and body weight. The present study was aimed at evaluating the effect of weight reduction after laparoscopic adjustable gastric banding (LAGB) on metabolic parameters and energy balance regulatory peptides. Patients were evaluated before and 6, 12, 24 or 36 months after the procedure, and a blood sample was obtained. Ghrelin rose 6 and 12 months after LABG, and then returned to near-baseline levels. In our study, the correlation between ghrelin and BMI was weak, but a strong significant correlation was maintained between leptin and BMI. We conclude that ghrelin is mainly stimulated by the negative caloric balance, and hypothesize that ghrelin is involved in maintaining a stable body weight, while leptin signals the body energy store; both hormones together are part of a more complex feedback mechanism.

Italian Group for Lap-Band System: results of multicenter study on patients with BMI < or =35 kg/m2.

BACKGROUND: The Lap-Band System is the most common bariatric operation world-wide. Current selection criteria do not include patients with BMI < or = 35. We report the Italian multicentre experience with BMI < or = 35 kg/m(2) over the last 5 years. PATIENTS AND METHODS: Data were obtained from 27 centres involved in the Italian Collaborative Study Group for Lap-Band System. Detailed information was collected on a specially created electronic data sheet (MS Access 2000) on patients operated in Italy since January 1996. Items regarding patients with BMI < or = 35 were selected. Data were expressed as mean +/- SD except as otherwise indicated. RESULTS: 225 (6.8%) out of 3,319 Lap-Band patients were recruited from the data-base. 15 patients, previously submitted to another bariatric procedure (BIB =14; VBG= 1) were excluded. 210 patients were eligible for study (34M/176F, mean age 38.19+/-11.8, range 17-66 years, mean BMI 33.9+/-1.1, range 25.1-35 kg/m(2), mean excess weight 29.5+/-7.1, range 8-41). 199 comorbidities were diagnosed preoperatively in 55/210 patients (26.2%). 1 patient (0.4%) (35 F) died 20 months postoperatively from sepsis following perforation of dilated gastric pouch. There were no conversions to laparotomy. Postoperative complications presented in 17/210 patients (8.1%). Follow-up was obtained at 6, 12, 24, 36, 48 and 60 months. At these time periods, mean BMI was 31.1+/-2.15, 29.7+/-2.19, 28.7+/-3.8, 26.7+/-4.3, 27.9+/-3.2, and 28.2+/-0.9 kg/m(2) respectively. Co-morbidities completely resolved 1 year postoperatively in 49/55 patients (89.1%). At 60 months follow-up, only 1 patient (0.4%) has a BMI >30. CONCLUSIONS: Although surgical indications for BMI < or = 35 remain questionable, the Lap-Band in this study demonstrated that all but 1 patient achieved normal weight, and most lost their co-morbidities with a very low mortality rate.

The Italian Group for LAP-BAND: predictive value of initial body mass index for weight loss after 5 years of follow-up.

BACKGROUND: Laparoscopic of the LAP-BAND System placement stage of obesity is a safe operation, but its indication in terms of stage of obesity is controversial. The aim of this study was to evaluate the 5 years stage of obesity results for weight loss in patients with varying preoperative ranges of body mass index (BMI). METHODS: Data were obtained from the Italian Collaborative Study Group for LAP-BAND System (GILB) registry. Detailed information was collected on a specifically created database (MS Access 2000) for patients operated on in Italy from January 1996 to 2003. Patients operated on between January 1996 and December 1997 were allocated to four groups according to preoperative BMI range: 30-39.9 kg/m(2) (group A), 40-49.9 kg/m(2) (group B), 50-59.9 kg/m(2) (group C), and =60 kg/m(2) (group D) percent estimated weight loss respectively. Postoperative complications, mortality, BMI, BMI loss, and (%EWL) were considered in each group. Data are expressed as mean +/- SD, except as otherwise indicated. Statistical analysis was done by means of Fisher's exact test, and p < 0.05 was considered significant. RESULTS: After 5 years from LAP-BAND System surgery, 573 of 3,562 patients were eligible for the study. One hundred fifty-five of 573 (27.0%) were lost to follow-up, 24 of 418 (5.7%) underwent band removal due to complications (gastric pouch dilation, band erosion), eight of 418 (1.9%) were converted to other bariatric procedures, five of 418 (1.2%) died of causes not related to the operation or the band, and 381 of 573 (66.5%) were available for follow-up. Based on 96, 214, 64, and seven patients their preoperative BMI, Were allocated to groups A, B, C, and D, respectively. At time of follow-up mean BMI was 27.5 +/- 5.2 in group A, 31.6 +/- 4.7 in group B, 37.6 +/- 17.3 in group C, and 41.4 +/- 6.9 kg/m(2) in group D. Mean BMI loss was 9.8 +/- 5.4, 12.9 +/- 5.2, 15.8 +/- 8.1, and 23.2 +/- 4.9 kg/m(2), respectively, in groups A, B, C, and D. Mean %EWL at the same time was 54.6 +/- 32.3 in group A, 54.1 +/- 17.2 in group B, 51.6 +/- 35 in group C, and 59.l +/- 17.1 in group D. CONCLUSION: Initial BMI in this series did not correlate with %EWL 5 years after the operation. In fact %EWL was almost the same in each group, independent of preoperative weight. Initial BMI was an accurate indicator of the results obtained 5 years after LAP-BAND in group C (50-59.9 kg/m(2)) and D (=60 kg/m(2)) patients, who remained morbidly obese despite their %EWL.

Morbid obesity: evaluation of metabolic indexes after adjustable silicone gastric banding.

Morbid obesity is frequently associated with other characteristics of metabolic syndrome and is related to an increased risk of cardiovascular disease. This study aimed at evaluating time-course changes in body weight, body mass index (BMI), insulin sensitivity indexes and lipid profile in severely obese patients who underwent adjustable silicone gastric banding. We studied 19 obese subjects before and 6-36 months after surgery. An oral glucose tolerance test was performed in all non-diabetic patients. All subjects were evaluated using insulin sensitivity indexes (ISI-HOMA and QUICKI), lipid profile, and anthropometric parameters (WHR, WC, BMI), and body composition was assessed with bioelectrical impedance analysis (BIA). Most of the weight reduction occurred within the first 6-12 months, followed by near stabilisation or even weight regain. We found a significant decrease in fasting insulin, improvement in waist-hip ratio, reduction in BMI and fat mass percent. We observed an improvement in insulin sensitivity evaluated by means of ISI-HOMA and QUICKI. Bariatric surgery was an effective therapeutic approach for these obese patients because it reduced both weight and insulin resistance, along with improving metabolic parameters. Improvement in metabolic parameters appears to precede body weight reduction.

Lap Band adjustable gastric banding system: the Italian experience with 1863 patients operated on 6 years.

BACKGROUND: The Lap Band system procedure is currently the most common bariatric surgical procedure worldwide. This is an interim report of the experience of the 27 Italian centers participating in the national collaborative study group for Lap Band (GILB). METHODS: An electronic database was specifically created. It was mailed and e-mailed to all of the surgeons now performing the laparoscopic gastric banding operation in Italy. RESULTS: Beginning in January 1996, 1893 patients were recruited for the study. There were 1534 women and 359 men with a mean body mass index (BMI) of (range 30.4-83.6) and a mean age of 37.8 +/- 10.9 years (range; 17-74). The mortality rate has been 0.53% (n = 10), mainly due to cardiovascular complications (myocardial infarction, pulmonary embolism). The laparotomic conversion rate has been 3.1% (59/1893) and was higher in superobese patients (BMI>50) than in to morbidly obese patients (BMI <50) (p <0.05). Postoperative complications occurred in 193 patients (10.2%), including tube port failure (n = 79; 40.9%), gastric pouch dilation (GPD) (n = 93; 48.9%), and gastric erosion (n = 21, 10.8%). Most GPD (65.5%) occurred during the first 50 patients treated at each center. The incidence of GPD decreased as the surgeons acquired more experience. Surgery for complications was often performed by laparoscopic access, rarely via laparotomy. No death was recorded as a consequence of surgery to treat complications. Weight loss has been evaluated at the following intervals: 6, 12, 24, 36, 48, 60, and 72 months, with BMI 37.9, 33.7, 34.8, 34.1, 32.7, 34.8, and 32. CONCLUSIONS: The Lap Band system procedure has a very low mortality rate and a low morbidity rate and it yields satisfactory weight loss. Surgery for complications can be performed safely via laparoscopic access.

Multiscale modelling as a tool to prescribe realistic boundary conditions for the study of surgical procedures.

This work was motivated by the problems of analysing detailed 3D models of vascular districts with complex anatomy. It suggests an approach to prescribing realistic boundary conditions to use in order to obtain information on local as well as global haemodynamics. A method was developed which simultaneously solves Navier-Stokes equations for local information and a non-linear system of ordinary differential equations for global information. This is based on the principle that an anatomically detailed 3D model of a cardiovascular district can be achieved by using the finite element method. In turn the finite element method requires a specific boundary condition set. The approach outlined in this work is to include the system of ordinary differential equations in the boundary condition set. Such a multiscale approach was first applied to two controls: (i) a 3D model of a straight tube in a simple hydraulic network and (ii) a 3D model of a straight coronary vessel in a lumped-parameter model of the cardiovascular system. The results obtained are very close to the solutions available for the pipe geometry. This paper also presents preliminary results from the application of the methodology to a particular haemodynamic problem: namely the fluid dynamics of a systemic-to-pulmonary shunt in paediatric cardiac surgery.

Results of the Italian multicenter study on 239 super-obese patients treated by adjustable gastric banding.

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) is the most common bariatric operation. This study is a retrospective analysis of the multicenter Italian experience in patients with BMI > 50 over the last 4 years. METHODS: An electronic data sheet made for LAGB-operated patients since January 1996, was mailed and e-mailed to all surgeons involved in this kind of procedure in Italy. Items regarding patients with BMI > 50 were selected. Analysis used Fisher's exact test and logarithmic regression analysis (P < 0.05 significant). Data were expressed as mean +/- SD. RESULTS: 239 patients (13.3%), out of 1,797 Lap-Band operated patients entered the study (179F / 60M), with mean age 37.6 +/- 11.3 years (19-69) and mean BMI 54.6 +/- 4.8 (50.1-83.6). Laparotomic conversion rate was 5.4% (44/239). Postoperative complications occurred in 24 / 239 patients (9.0%). Follow-up was obtained in 218 / 218, 198 / 198, 121 /147, 75 / 93, 30 / 38 LAGB patients at 6,12, 24, 36, and 48 months respectively. At these time periods, mean BMI was 46.7, 43.9, 42.2, 41.9, and 39.3 kg/m2. At the same intervals, mean %EWL was 24.1, 34.1, 38.8, 38.9, and 52.9%. The number of patients with < 25% EWL at 12, 24, 36, and 48 months follow-up were 34, 10, 4, and 0. Serious co-morbidities (189 in 124 of 239, 57%) had completely resolved 1 year postoperatively in 74 / 124 of the patients (59.6%). CONCLUSION: Although super-obese patients following the LAGB remain obese with BMI > 35, in the short-term most lose their co-morbidities, with a very low morbidity and mortality rate.

Laparoscopic Italian experience with the Lap-Band.

BACKGROUND: An increasing number of surgeons with different levels of experience with laparoscopic surgery and open obesity surgery have started to perform laparoscopic implantation of the Lap-Band. METHODS: An electronic patient data sheet was created and was mailed and e-mailed to all surgeons performing laparoscopic adjustable silicone gastric banding (LASGB) in Italy. Patients were recruited since January 1996. Data on 1,265 Lap-Band System operated patients (258 M/1,007 F; mean BMI 44.1, range 27.0-78.1; mean age 38, range 17-74 years) were collected from 23 surgeons performing this operation. RESULTS: Intra-operative mortality was absent. Post-operative mortality was 0.55% (7 patients) for causes not specifically related to LASGB implantation. The laparotomic conversion rate was 1.7% (22 patients). LASGB related complications occurred in 143 patients (11.3%). Pouch dilatation was diagnosed in 65 (5.2%), and 28 (2.2%) of these underwent re-operation. Band erosion was observed in 24 patients (1.9%). Port or connecting tube-port complications occurred in 54 patients (4.2%), 12 of whom required revision under general anesthesia. Follow-up was obtained at 6, 12, 18, 24, 36 and 48 months, and mean BMI was respectively 38.4, 35.1, 33.1, 30.2, 32.1 and 31.5. The percentage of patients observed at each follow-up was > 60%. There was no intra-operative mortality and no complication-related mortality, with acceptable weight loss. CONCLUSION: The LASGB operation is safe and effective, and deserves wider use for treatment of morbid obesity.

[Spinal or epidural anaesthesia for caesarean section? Compared opinions]. / Anestesia spinale o epidurale nel taglio cesareo? Opinioni a confronto.

Regional anaesthesia during caesarean section reduces mortality directly related to anaesthesia. Epidural anaesthesia is a good choice when an epidural anaesthesia was performed during labor. General anaesthesia is recommended only for emergency caesarean section and when regional anaesthesia is contraindicated. The Authors describe the reasons for choicing an epidural or a spinal block. Main points supporting spinal block are facility in performing, quickness of the achievement of the block and a good quality of sensorial and motor block. On the other side epidural anaesthesia makes the anaesthesist able to titrate with exactness the level of sensorial block and offers a good postoperative analgesia. Because of the introduction of atraumatic needles PPDH has drammatically decreased: accidental PPDH takes place in a small but ingrained percentage. Recently spinal block has been described as a reliable choice even in preeclampsia and in pregnancy hypertension. Epidural opiates have a lower incidence of maddening side effects compared with spinal opiates and allow better maternal satisfaction as regard postoperative analgesia. In accordance with ASA guidelines there are no decisive reasons in order to choice spinal or epidural block: actually literature is unable to give a definitive suggestion about complications and advantages. The choice would be take place weighing up maternal wishes, fetal factors (elective versus urgent caesarean section) and the preferences of the anesthesiologist.

ViVa: the virtual vascular project.

The aim of the virtual vascular project (ViVa) is to develop tools for the modern hemodynamicist and cardiovascular surgeon to study and interpret the constantly increasing amount of information being produced by noninvasive imaging equipment. In particular, we are developing a system able to process and visualize three-dimensional (3-D) medical data, reconstruct the geometry of arteries of specific patients, and simulate blood flow in them. The initial applications of the system will be for clinical research and training purposes. In a later stage, we will explore the application of the system to surgical planning. ViVa is based on an integrated set of tools, each dedicated to a specific aspect of the data processing and simulation pipeline: image processing and segmentation; real-time 3-D volume visualization; 3-D geometry reconstruction; 3-D mesh generation; and blood flow simulation and visualization.

[Role of hyperbaric oxygen in the treatment of necrotizing infections of the soft tissues]. / Ruolo dell'ossigeno iperbarico nel trattamento delle infezioni necrotizzanti dei tessuti molli.

The Authors report their experience in the treatment of soft tissue necrotizing infections. The correct "timing" of the association of surgery, antibiotics and hyperbaric oxygen therapy is stressed. The good clinical results obtained in the patients examined confirm the usefulness of an early treatment modulated according to the needs of each single patient.

[Superselective spinal anesthesia for saphenectomy intervention. Comparison of 2 concentrations of hyperbaric bupivacaine]. / Anestesia spinale superselettiva per l'intervento di safenectomia. Confronto fra due concentrazioni di bupivacaina iperbarica.

BACKGROUND: High concentrations of intrathecal local anaesthetics may be neurotoxic. The purpose of this study was to compare the features of superselective spinal anaesthesia (ASS) obtained with an equivalent dose (5 mg) of 0.5% (available now also in Italy) and 1% hyperbaric bupivacaine. METHODS: A prospective study was carried out on 100 patients undergoing saphenectomy, who were randomized into two groups to receive either 0.5% bupivacaine 1 ml (group A) or 1% bupivacaine 0.5 ml (group B). The anaesthetic solution was injected 1 ml/min at L2-L3 with an atraumatic needle. During dural puncture and following 20 minutes patients were held with the operative side down. In every patient were recorded: quality and level of analgesia on dependent (operative) and non dependent sides; motor-block at the 20th minute and 2nd, 3rd and 4th hours on both sides; reduction per cent of systolic artery pressure (SAP) and heart rate (HR), incidence of hypotension (SAP < 90 mmHg) and bradycardia (HR < 50 bts/min); recovery of deambulation and micturition and side effects. RESULTS: Significant differences between the two groups have been found in: 1) number of thoracic segments blocked (3.22 vs 2.02); 2) motor block at the 2nd hour; 3) number of patients able to walk (19 vs 3) and to micturate (11 vs 3) at the 2nd hour. CONCLUSIONS: 0.5% hyperbaric bupivacaine can be successfully use in ASS; early regression of motor block is especially suitable for the requirements of day surgery.

Thoracic desmoid tumors: a rare evolution of rib fracture. Etiopathogenesis and therapeutic considerations.

The Authors report a case of thoracic desmoid tumor. The strict correlation between a previous chest injury and the site of desmoid tumor in this patient seems to strengthen the possible etiological role of trauma, as already suggested.

Clinically silent inflammatory gut lesions in undifferentiated spondyloarthropathies.

Gastrointestinal inflammation or infection can be associated with various forms of arthritis, such as, acute reactive arthritis triggered by enteritis due to gram-negative bacteria or ankylosing spondylitis and peripheral arthritis in relation to Crohn's disease and ulcerative colitis. Using colonoscopy, we have found a high prevalence of clinically silent inflammatory lesions in 38 patients (24 males and 14 females) affected by undifferentiated spondyloarthropathies (SpA). Microscopic inflammatory lesions were present in all the patients. Three patterns of nonspecific chronic inflammatory alterations were observed. No difference was noted between patients taking or not taking nonsteroidal anti-inflammatory drugs. Direct immunofluorescence demonstrated the presence of IgG, IgA, IgM, C3, C4 and fibrinogen in 75% of the specimens examined. The finding of chronic inflammatory gut lesions hypothesizes that a local activation of the immune system depending on the persistence of intestinal microbial antigens or toxins, due to impaired elimination or increased exposition, may have a part in the pathogenesis of SpA.

[The sternotomy and thoracotomy approaches in the treatment of differentiated thyroid cancer in an advanced phase]. / Approccio sternotomico e toracotomico nel trattamento del cancro differenziato della tiroide in fase avanzata.

The authors report their experience in the treatment of well-differentiated thyroid cancer. The analysis of 5 cases treated with extensive surgery give the opportunity to discuss about the use of sternotomy or thoracotomy to eradicate mediastinal lymph nodes. The importance of preoperative assessment, especially by histological examination is stressed as well as the role of surgery in the multidisciplinary approach for the treatment of the disease.

[The surgical treatment of a differentiated thyroid carcinoma infiltrating the large mediastinal veins]. / II trattamento chirurgico del carcinoma tiroideo differenziato infiltrante i grandi vasi venosi mediastinici.

The authors report on 2 patients affected by well-differentiated, locally advanced, thyroid carcinoma infiltrating the major mediastinal veins. Removal of the neoplastic mass was possible through a combined cervical and trans-sternal approach. Surgical indication, operative strategy and follow up are discussed. A review of the literature is also reported.