Importance of the numerical schemes in the CFD of the human nose.

Computational fluid dynamics of the air flow in the human nasal cavities, starting from patient-specific Computer Tomography (CT) scans, is an important tool for diagnostics and surgery planning. However, a complete and systematic assessment of the influence of the main modelling assumptions is still lacking. In designing such simulations, choosing the discretization scheme, which is the main subject of the present work, is an often overlooked decision of primary importance. We use a comparison framework to quantify the effects of the major design choices. The reconstructed airways of a healthy, representative adult patient are used to set up a computational study where such effects are systematically measured. It is found that the choice of the numerical scheme is the most important aspect, although all varied parameters impact the solution noticeably. For a physiologically meaningful flow rate, changes of the global pressure drop up to more than 50% are observed; locally, velocity differences can become extremely significant. Our results call for an improved standard in the description of this type of numerical studies, where way too often the order of accuracy of the numerical scheme is not mentioned.

[Lithium toxicity after bariatric surgery]. / Intoxication au lithium après chirurgie bariatrique.

Since many years a correlation between neuropsychiatric disorders and eating disorders resulting in obesity is well established. According to different studies, 1.2 - 4 % of patients scheduled for bariatric surgery are taking lithium as a mood stabilizer treatment for bipolar disorder. We are presenting a case of lithium toxicity after vertical sleeve gastrectomy surgery in a 40 years-old female. The patient developed severe neurological and renal signs needing an intensive care unit admission and continuous veno-venous hemodiafiltration. A literature review provides insights into physiological and pharmacokinetics changes that could contribute to lithium poisoning after bariatric surgery. This article illustrates the need for closer monitoring of lithium serum levels following bariatric surgery and presents guidance in managing lithium therapy during perioperative period based on experts' opinion.

Une corrélation entre troubles neuropsychiatriques et troubles alimentaires est maintenant établie depuis plusieurs années. Selon les études, 1,2 à 4% des patients éligibles pour une chirurgie bariatrique ont un traitement chronique comprenant du lithium (1-3). Nous rapportons le cas d'une patiente de 40 ans qui développe une intoxication au lithium dans le décours d'une «sleeve¼ - gastrectomie avec des signes neurologiques et rénaux sévères nécessitant sa prise en charge aux soins intensifs avec hémodiafiltration continue veino-veineuse. Nous détaillons les modifications physiologiques et pharmacocinétiques susceptibles d'induire un surdosage en lithium après une telle chirurgie. Nous revoyons enfin les recommandations concernant la prise en charge de l'intoxication au lithium ainsi que les mesures préventives péri-opératoires afin d'éviter une telle situation.

Treatment of rectovaginal fistula after colorectal resection with endoscopic stenting: long-term results.

AIM: To treat patients with rectovaginal fistula after anterior resection for cancer using self-expanding metal stents. METHOD: Ten patients of mean age of 56.3 years with rectovaginal fistula after colorectal resection for cancer were treated with endoscopic placement of a self-expanding metal stent. In three patients a diverting proximal stoma had been performed elsewhere. The rectal opening of the fistula was located from 3 to 10 cm from the anal verge (mean 6 cm). All patients had preoperative radiotherapy. In seven patients the stent was placed as the initial treatment while three referred patients had had multiple failed operations. RESULTS: There were no complications after the procedure. At a mean follow-up of 24 months the rectovaginal fistula has healed without major faecal incontinence in eight patients. In the remaining two the fistula has reduced significantly in size to allow a successful flap transposition. CONCLUSION: Endoscopic placement of a self-expanding metal stent is a valid adjunct to treat patients with rectovaginal fistula after colorectal resection for cancer.

[Abdominal CSF pseudocyst recurrence in a 14-year-old patient with ventricular-peritoneal shunt]. / Récurrence d'un kyste abdominal de liquide céphalo-rachidien chez un adolescent de 14 ans porteur d'un drain ventriculo-péritonéal.

Abdominal cerebrospinal fluid (CSF) pseudocyst is a rare complication of ventricular-peritoneal shunt (VPS) but needs to be considered in every patient with abdominal complaints or signs of intracranial hypertension (IH). The pathogenesis of pseudocysts remains unclear. Diverse predisposing factors have been proposed such as previous abdominal surgeries, multiple VPS revisions, infections, history of necrotizing enterocolitis, and nonspecific inflammatory processes. We report the case of a 14-year-old patient, known to have a VPS as intraventricular hemorrhage treatment, presenting cephalalgia, vomiting, apathy, and an indurate abdominal mass without fever. The first abdominal CSF pseudocyst diagnosis had been established 3 months earlier. Abdominal ultrasounds confirmed a large homogeneous cyst with the shunt tip within the pseudocyst. Cerebral CT revealed an increased ventricular size. An exploratory laparotomy with cyst aspiration, lysis of adhesions, excision of cystic walls, and repositioning of the peritoneal catheter was performed. No antibiotics were initiated given that the cultures were negative. Ultrasonography proved to be the method of choice in the diagnosis of VPS abdominal complications, especially CSF pseudocyst. CT can also reliably confirm the pseudocyst. In case of IH signs, a cerebral CT scan can be performed to evaluate the ventricular distension and to check the shunt position. Various methods to process the cyst have been described in the medical literature, but the recurrence rate remains elevated (25-100%). Then the probability of an infection without any clinical sign has to be considered. In case of suspected infection, the VPS is removed and replaced by an external ventricular drain. Antibiotics are started and adjusted to the results of the CSF culture. If there is no direct sign of infection, only the distal catheter is externalized and antibiotics are introduced until infection is treated. Depending on the peritoneal absorption state, the distal catheter is replaced in the abdominal cavity or in the atrium, the pleural space or the gallbladder if there is no suitable place for repositioning. If the peritoneal state allows it, a laparoscopic procedure is recommended to avoid peritoneal adhesion formation increasing the recurrence rate of CSF pseudocyst.

Self-expandable metal stents in the treatment of benign anastomotic stricture after rectal resection for cancer.

AIM: To evaluate the use of self-expandable metallic stents to treat patients with symptomatic benign anastomotic stricture after colorectal resection. METHOD: Ten patients with a benign symptomatic anastomotic stricture after colorectal resection were treated with endoscopic placement of a self-expandable metal stent. RESULTS: The stent was placed successfully in all 10 patients without any major morbidity. At a mean follow-up of 18 months the stenosis was resolved successfully in 7 out 10 patients (70%). The remaining three patients were subsequently treated successfully with balloon dilatation. CONCLUSION: Self-expandable metal stents represent a valid alternative to balloon dilatation to treat patients with benign symptomatic anastomotic stricture after colorectal resection for cancer.

Computed tomographic colonography (virtual colonoscopy): blinded prospective comparison with conventional colonoscopy for the detection of colorectal neoplasia.

BACKGROUND AND STUDY AIMS: Computed tomographic colonography (CTC), also known as virtual colonoscopy, is a recently introduced imaging modality for the detection of colorectal neoplasia. The aim of our study was to evaluate the performance of CTC in a blinded comparison with conventional colonoscopy. PATIENTS AND METHODS: A total of 66 consecutive, symptomatic patients underwent spiral computed tomography (CT) examination after standard bowel preparation. CT images were analyzed and subsequently compared with conventional colonoscopy findings. RESULTS: Conventional colonoscopy detected 15 colorectal carcinomas and 52 polyps. CTC correctly identified all carcinomas, 13 of 14 polyps greater than 10.0 mm (sensitivity 92.8 %; 95 % confidence interval (95 % CI); 77 - 100), 11 of 13 polyps between 6.0 and 9.0 mm (sensitivity 84.6 %; 95 % CI; 62 - 100), and six of 25 polyps smaller than 5.0 mm (sensitivity 24 %; 95 % CI; 6 - 42). The per-patient sensitivity and specificity were 93.7 % and 94.1 %, respectively. CONCLUSIONS: Computed tomographic colonography is an accurate imaging modality for the detection of colorectal neoplasia, especially for lesions larger than 6.0 mm in diameter.

[Caroli's disease: 2 case reports and review of the literature]. / La malattia di Caroli: descrizione di due casi clinici e revisione della letteratura.

The most appropriate management of Caroli's disease is still controversial: in fact many surgical modalities have been proposed for patients exhibiting cholangitis or intrahepatic lithiasis, but these approaches have been seldom performed on asymptomatic or oligosymptomatic patients. However, this figure, due to the surgical risk related with a bilio-enteric anastomosis or with an hepatic resection, should be always compared with the possible development of a cholangiocarcinoma within the enlarged biliary tree (7%), as clearly shown in the 2 cases herein reported.

[Endometriosis of the abdominal wall: a clinical case report and a review of the literature]. / Endometriosi della parete addominale: presentazione di un caso clinico e revisione della letteratura.

The authors report one case of abdominal wall endometriosis secondary to cesarean section. They emphasize the rarity of this localization and discuss about the incidence of extrapelvic endometriosis stressing the importance of this pathology in the differential diagnosis with other disease.

The importance of heterogeneity and of multiple site sampling in the prospective determination of deoxyribonucleic acid flow cytometry.

Multiple fresh specimens from 59 nonsmall cell carcinomas of the lung, 38 carcinomas of the gastric tract and 55 carcinomas of the colon and rectum were analyzed by deoxyribonucleic acid (DNA) flow cytometry (FC) after radical resection to evaluate tumor ploidy as an independent prognostic factor. The minimum follow-up period was five years (range of five to ten years). Aneuploidy was observed in 98.0 percent of carcinomas of the lung, in 70.9 percent of carcinomas of the colon and rectum and in 63.1 percent of carcinomas of the gastric tract. FC DNA heterogeneity, in terms of different number of DNA stem lines or different DNA indices between core and periphery, or both, was found in 50.0 percent of carcinomas of the lung, 47.0 percent of carcinomas of the colon and rectum and in 34.5 percent of carcinomas of the gastric tract. A diploid pattern was more frequently observed in less advanced stages of the gastrointestinal tract. By univariate analysis (Kaplan-Meier), patients with carcinoma of the lung with hypodiploid or hypertetraploid peaks, or both, and aneuploid gastric tumors had poorer prognosis. These differences were only marginally significant. Cox analysis demonstrated that the single most important prognostic variable for predicting the overall survival rate was the stage of disease. Tumor DNA content can be considered a marker of advanced stages, particularly in tumors of the gastrointestinal tract, but there is no evidence that it is an independent prognostic variable able to predict long term survival in patients who have been radically resected.

[Surgery by exeresis for gastric carcinoma. An analysis of 165 consecutive cases]. / Chirurgia d'exeresi per carcinoma gastrico. Analisi di 165 casi consecutivi.

Surgery is still considered the best approach in gastric cancer. The aim of this study was to identify the most important factors involved in the determination of long-term survival. Total and subtotal gastrectomy were analysed. Long-term survival in these patients was strictly correlated with the stage of disease and the infiltration of resection margins. Early diagnosis is confirmed to be the most important factor in the long-term survival of these patients.

Flow cytometric analysis in colorectal carcinoma: prognostic significance of cellular DNA content.

The prognostic value of DNA ploidy status was evaluated prospectively in 70 patients with colorectal carcinoma. Cellular DNA content was measured by flow cytometry from fresh specimens with multiple site sampling. Seventy-five percent of cases exhibited a DNA aneuploid pattern. In a univariate analysis, DNA ploidy status showed a statistically significant correlation with survival (p less than 0.05), weaker than Dukes' stage (p less than 0.001). No correlation was observed between survival and presence of multiple DNA stemlines. In a multivariate analysis, Dukes' stage was the strongest prognostic indicator (p = 0.01) while DNA ploidy status did not show an independent prognostic value. It is concluded that DNA ploidy status is associated with pathological features of aggressive malignancy, but it does not have a determinant role in predicting survival.

[Prognostic factors in stomach cancer: invasion of gastric serosa and lymph node involvement]. / Fattori di prognosi del cancro dello stomaco: invasione della sierosa gastrica e coinvolgimento dei linfonodi.

Concerning prognostic factors in gastric cancer, the Authors analyse the main two influencing long-term prognosis: the depth of penetration of the tumor in the gastric wall and the presence of lymph node metastasis. 194 operated gastric neoplasms were staged, according to TNM classification (U.I.C.C., 1987) and divided into 4 groups: in the first group both the serosa and the lymph nodes were tumor-free; in the second both were involved; in the third only lymph nodes were involved; in the fourth only the serosa was involved. Crossed statistic analysis between groups showed that the only factor that influenced the long-term survival is the node involvement in the patients with tumor-free gastric serosa. These results correspond to most of the others in literature, and point to the connection between these two factors in defining the stage of the disease.

Early gastric cancer.

A clear difference in survival among the patients affected by gastric cancer has been observed worldwide between Early Gastric Cancer (EGC) and Advanced Gastric Cancer (AGC). Optical fiber endoscopy has allowed a sharp increase in the number of diagnoses of EGC since the sixties. Among 182 our patients operated on, 19 [10.4%] had an EGC. A difference in incidence was found between males and females, while no difference was found in the age distribution. The main symptom was epigastric pain; EGCS common findings were ulceration or a flat tumor. Surgical procedures were carried out with the same criteria used for AGC. No difference was found in the tumor location. Local spread was studied according to the Japanese Research Society for Gastric Cancer, while histological type was classified according to Lauren classification. Crude 5-year survival was 80% (8 out of 10), with a mean of 76.8 +/- 13 (SEM) months.

Intrarectal ultrasonography in the preoperative staging of rectal cancer.

Intrarectal ultrasonography is a new imaging method used in the preoperative staging of rectal cancer. Twenty five patients with proven rectal cancer were submitted to preoperative intrarectal ultrasonography; 24 were resected. Real time scanner with a linear probe of 5 MHz was employed. Five sonographic structures corresponding to the five histological layers were evidenced. Ultrasound T staging was compared to pathology, using UICC classification. In all but two cases pathology corresponded to ultrasound T staging (accuracy 92%). Perirectal nodal involvement was also investigated. It is concluded that intrarectal ultrasonography will play a definite role in the preoperative staging as well as in programming treatment of rectal carcinoma.