Silicone-based simulation models for peripheral nerve microsurgery

Background

There is a need for a peripheral nerve model on which surgeons-in-training can simulate the repair of nerve injuries at their own pace. Although practicing on animal models/cadavers is considered the “gold standard” of microsurgical training, the proposed model aims to provide a platform for improving the technical skills of surgical trainees prior to their practice on cadaver/animal models. In addition, this model has the potential to serve as a standardized test medium for assessing the skill sets of surgeons.

Effects of parity on pregnancy hormonal profiles across ethnic groups with a diverse incidence of breast cancer.

Epidemiologic evidence suggests that a full-term pregnancy may affect maternal risk of breast cancer later in life. The objective of this cross-sectional study was to compare circulating levels of maternal hormones affecting breast differentiation (human chorionic gonadotropin and prolactin) and proliferation [alpha-fetoprotein, insulin-like growth factor I (IGF-I), and estradiol] between women at a low to moderate risk (Asians and Hispanics), as compared with women at a high risk for breast cancer (Caucasians and African-Americans). Between May 2002 and December 2004, a total of 586 pregnant women were approached during a routine prenatal visit. Among them, 450 women (206 Caucasian, 126 Asian, 88 Hispanic, and 30 African-American) met the inclusion criteria and signed the informed consent. Only singleton pregnancies were considered. Blood samples were drawn during the second trimester of pregnancy. Laboratory analyses were done using the IMMULITE 2000 immunoassay system. Gestational age standardized mean levels of estradiol, IGF-I, and prolactin were significantly higher in Hispanic women compared with Caucasian women. Mean concentration of IGF-I was significantly higher in African-American women compared with Caucasian and Asian women. No significant differences in pregnancy hormone levels were observed between Caucasian and Asian (predominantly second-generation Chinese) women in this study. Irrespective of ethnicity, women who had their first pregnancy had substantially higher mean levels of alpha-fetoprotein, human chorionic gonadotropin, estradiol, and prolactin compared with women who previously had at least one full-term pregnancy. These data suggest that circulating pregnancy hormone levels may explain some of the ethnic differences in breast cancer risk.     

An algorithm for deciding alternative grafting materials used in secondary rhinoplasty.

Severe middle vault deformity with disturbed nasal form and function is one of the most challenging procedures to correct in a secondary rhinoplasty. Reconstructing the deformity with autologous septal cartilage would be the primary choice of most surgeons, if it were always available. However in certain cases the lack of a sufficient quantity of autologous cartilage has forced surgeons to explore other viable options. This paper discusses our experience with the combined use of spreader and dorsal onlay grafts from various materials in the reconstruction of severe middle vault deformity in 110 patients. In follow up, (between 6 and 42 months; mean 21 months) all patients were noted to have improved in both aesthetics and function with no major complications noted. In summary, this study proposes that any engrafting material can be used safely when the proper surgical principals and technique are employed.     

Sentinel Bleeding After Pancreaticoduodenectomy: A Disregarded Sign

Introduction Delayed massive hemorrhage induced by pancreatic fistula after pancreaticoduodenectomy is a rare but life-threatening complication. The purpose of this study was to analyze the clinical course of patients with late hemorrhage, with or without sentinel bleeding, to better define treatment options in the future. Material and Methods From April 1998 to December 2006, 189 pancreaticoduodenectomies were performed. Eleven patients, including two patients referred from other hospitals, were treated with delayed massive hemorrhage occurring 5 days or more after pancreaticoduodenectomy. Sentinel bleeding was defined as minor blood loss via surgical drains or the gastrointestinal tract with an asymptomatic interval until development of hemorrhagic shock. The clinical data of patients with bleeding episodes were analyzed retrospectively. Results Eight of the 11 patients had sentinel bleeding, and seven of them had it at least 6 h before acute deterioration. Seven out of 11 patients died, five out of eight with sentinel bleeding. No differences could be detected between patients with or without sentinel bleeding before delayed massive hemorrhage. The only difference found was that non-surviving patients were significantly older than surviving patients. Delayed massive hemorrhage is a common cause of death after pancreaticoduodenostomy complicated by pancreatic fistula formation. The observation of sentinel bleeding should lead to emergency angiography and dependent from the result to emergency relaparotomy to increase the likelihood of survival.     

Airway hyper-responsiveness to adenosine 5''-monophosphate in preschool-age children with asthma

Airway hyper-responsiveness (AHR) to adenosine 5'-monophosphate (AMP) is closely associated with airway inflammation; however, not all asthmatic patients are responsive to it. This study was planned to investigate the predictive factors of AHR to AMP in asthmatic children aged between 3 and 6 yr. We performed a retrospective analysis of data from 63 asthmatic preschool-age children who were challenged by AMP in our department. All children were characterized by skin-prick tests, serum immunoglobulin E (IgE) levels, peripheral blood eosinophil percentage and bronchial challenge with methacholine (MCH) and AMP. Potential determinants for AHR to AMP were assessed within the group. AHR to AMP was found in 46% of preschool-age children with asthma, while that of MCH was 93.7%. All children responsive to AMP were also responsive to MCH. The geometric mean provocative concentration of MCH and AMP causing a 15% fall in transcutaneous oxygen tension (PC(15)PtcO(2)MCH and AMP) were 0.55 mg/ml (0.004-9.19) and 10.53 mg/ml (0.59-342.89), respectively. AMP-responsive children did not differ from non-responsive ones with respect to demographic factors, geometric mean PC(15)PtcO(2)MCH and atopic status. The median serum IgE level was significantly higher in AMP-responsive group than the non-responsive ones (p = 0.011). The peripheral blood eosinophilia was more frequent among responsive children (p = 0.019), and it was found as the only predictive factor for AMP responsiveness in preschool-age children with asthma in logistic regression model (odds ratio: 5.14; 95% CI: 1.23-21.47; p = 0.025). AMP responsiveness may be predicted by peripheral blood eosinophilia but not with atopy markers in young children with asthma.     

Comparison of CT-guided sclerotherapy with using 95% ethanol and 20% hypertonic saline for managing simple renal cyst.

OBJECTIVE: We wanted to compare the efficacies of 95% ethanol and 20% hypertonic saline (HS) sclerotherapies that were performed in a single session under CT guidance for the management of simple renal cysts. MATERIALS AND METHODS: A prospective series of 74 consecutive patients (average age: 57.6 +/- 8.1 years) with simple renal cysts were enrolled in this study. They were randomized into two groups and 95% ethanol or 20% HS, respectively, corresponding to 25% of the aspiration volume, was injected. Treatment success was determined six months later with follow-up clinical evaluation and performing ultrasonography. RESULTS: The sclerotherapy was accepted as technically successful without major complications in all except two patients who were excluded because of a communication between the simple renal cyst and the pelvicalyceal collecting system. Thirty-six patients in the ethanol group received sclerotherapy with 95% ethanol and 36 patients in the HS group underwent sclerotherapy with 20% HS. The complete regression ratio of the ethanol group was significantly higher (94% versus 72%, respectively) than that of the HS group. There was one patient with partial regression in each group. The failure ratio of the ethanol group was significantly lower (3% versus 25%, respectively) than that of the HS group. CONCLUSION: Ethanol sclerotherapy under CT guidance is a successful and safe procedure and it can be used for the treatment of simple renal cysts. Sclerotherapy with 95% ethanol is more effective than 20% HS sclerotherapy. Sclerotherapy with HS may be an option for patients preferring to undergo a less painful treatment procedure.     

An intelligent system for diagnosis of the heart valve diseases with wavelet packet neural networks

In this paper, an intelligent system is presented for interpretation of the Doppler signals of the heart valve diseases based on the pattern recognition. This paper especially deals with combination of the feature extraction and classification from measured Doppler signal waveforms at the heart valve using the Doppler Ultrasound. Because of this, a wavelet packet neural network model developed by us is used. The model consists of two layers: wavelet and multi-layer perceptron. The wavelet layer is used for adaptive feature extraction in the time-frequency domain and is composed of wavelet packet decomposition and wavelet packet entropy. The multi-layer perceptron used for classification is a feed-forward neural network. The performance of the developed system has been evaluated in 215 samples. The test results showed that this system was effective in detecting Doppler heart sounds. The correct classification rate was about 94% for abnormal and normal subjects.