751 research outputs found

    Anatomic segmentectomy for stage I nonā€“small-cell lung cancer: Comparison of video-assisted thoracic surgery versus open approach

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    ObjectivesAnatomic segmentectomy is increasingly being considered as a means of achieving an R0 resection for peripheral, small, stage I nonā€“small-cell lung cancer. In the current study, we compare the results of video-assisted thoracic surgery (n = 104) versus open (n = 121) segmentectomy in the treatment of stage I nonā€“small-cell lung cancer.MethodsA total of 225 consecutive anatomic segmentectomies were performed for stage IA (n = 138) or IB (nĀ = 87) nonā€“small-cell lung cancer from 2002 to 2007. Primary outcome variables included hospital course, complications, mortality, recurrence, and survival. Statistical comparisons were performed utilizing the t test and Fisher exact test. The probability of overall and recurrence-free survival was estimated with the Kaplan-Meier method, with significance being estimated by the log-rank test.ResultsMean age (69.9 years) and gender distribution were similar between the video-assisted thoracic surgery and open groups. Average tumor size was 2.3 cm (2.1 cm video-assisted thoracic surgery; 2.4 cm open). Mean follow-up was 16.2 (video-assisted thoracic surgery) and 28.2 (open) months. There were 2 perioperative deaths (2/225; 0.9%), both in the open group. Video-assisted thoracic surgery segmentectomy was associated with decreased length of stay (5 vs 7 days, P < .001) and pulmonary complications (15.4% vs 29.8%, P = .012) compared with open segmentectomy. Overall mortality, complications, local and systemic recurrence, and survival were similar between video-assisted thoracic surgery and open segmentectomy groups.ConclusionsVideo-assisted thoracic surgery segmentectomy can be performed with acceptable morbidity, mortality, recurrence, and survival. The video-assisted thoracic surgery approach affords a shorter length of stay and fewer postoperative pulmonary complications compared with open techniques. The potential benefits and limitations of segmentectomy will need to be further evaluated by prospective, randomized trials

    Crystal-Like geometric modeling

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    Crystals are natural phenomena that exhibit high degrees of order, symmetry, and recursion. They naturally form interesting and inspiring geometric shapes. This thesis provides geometric modeling techniques for creating shapes with crystallike geometry. The tiered extrusion method, along with a face grouping technique, simplifies the creation of complex, intricate faceted shapes. In combination with remeshing, these methods provide the capability to generate geometric shapes exhibiting planar faces, symmetry, and fractal geometry. The techniques have also been implemented in software, as a proof of concept. They are used in an interactive geometric modeling system, in which users can use these techniques to create crystal-like shapes. The crystal-like modeling operations are shown to successfully create beautiful geometric shapes. The methods improve upon traditional modeling capabilities, providing an easier way to create crystal-like geometric shapes

    Acute idiopathic heart failure following laparoscopic myotomy for achalasia of the esophagus

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    Background: Stress-induced cardiomyopathy, also known as takotsubo cardiomyopathy, is not fully understood. It is thought to occur in patients who have signs and symptoms consistent with acute myocardial infarction but display no obstructive coronary lesions during heart catheterization. Characteristics include transient left ventricular dysfunction, wall motion abnormalities on echocardiogram, new electrocardiographic ST-segment changes, and the occurrence of a precipitating stressor. Case Report: We present a patient who underwent Heller myotomy and suffered acute heart failure in the immediate postoperative period. Left heart catheterization revealed clean coronary arteries, and the patient fully recovered days later. While difficult to fully exclude drug-related causes, we believe this case to be consistent with takotsubo cardiomyopathy. Conclusion: This unusual postoperative complication following uneventful laparoscopic surgery should be kept in mind when unsuspected cardiovascular compromise is seen in the early perioperative recovery period. In addition to the rare occurrence of acute coronary ischemia syndromes and possible perioperative pulmonary embolic events, cardiovascular decompensation related to acute stress syndromes or idiopathic pharmacologic responses must be considered. Even patients who seem most healthy can have complications that warrant immediate attention and treatment

    Scales and Scale-like Structures

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    Scales are a visually striking feature that grows on many animals. These small, rigid plates embedded in the skin form an integral part of our description of ļ¬sh and reptiles, some plants, and many extinct animals. Scales exist in many shapes and sizes, and serve as protection, camouļ¬‚age, and plumage for animals. The variety of scales and the animals they grow from pose an interesting problem in the ļ¬eld of Computer Graphics. This dissertation presents a method for generating scales and scale-like structures on a polygonal mesh through surface replacement. A triangular mesh was covered with scales and one or more proxy-models were used as the scales shape. A user began scale generation by drawing a lateral line on the model to control the distribution and orientation of scales on the surface. Next, a vector ļ¬eld was created over the surface to control an anisotropic Voronoi tessellation, which represents the region occupied by each scale. Then these regions were replaced by cutting the proxy model to match the boundary of the Voronoi region and deform the cut model onto the surface. The ļ¬nal result is a fully connected 2-manifold that is suitable for subsequent post-processing applications, like surface subdivision

    Minimally invasive resection of benign esophageal tumors

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    ObjectiveBenign tumors of the esophagus are uncommon. Traditionally, resection has required thoracotomy or laparotomy. In this study we present our experience with resection of these tumors using a minimally invasive approach.MethodsA retrospective review of patients who underwent resection of benign esophageal tumors between 1990 and 2005 was conducted. Operative approach, tumor size, and outcomes after surgery were recorded.ResultsTwenty patients were identified (leiomyoma: n = 15; stromal tumor: n = 3; granular cell tumor, n = 1; schwannoma: n = 1). Four patients underwent an open approach (right thoracotomy); the remainder were resected using minimally invasive techniques (thoracoscopy, n = 9; laparoscopy, n =7). There were no postoperative leaks or other major complications after surgery. Two patients required repair of a mucosal injury during resection. Mean tumor size in the open group was 8.1 cm (range 7ā€“10 cm) compared with 3.5 cm (range 0.9ā€“8 cm) in the minimally invasive group. Median length of stay was 5.5 days in the open group compared with 2.75 days in the minimally invasive group. Five patients subsequently required fundoplication for worsening (n = 3) or new-onset (n = 2) gastroesophageal reflux disease after tumor resection.ConclusionsMinimally invasive resection of benign esophageal tumors is technically safe and associated with a shorter length of stay compared with open approaches. Although no specific cutoff for size could be identified, most tumors greater than 7 cm were removed by thoracotomy. The subsequent development of reflux may be related to the esophageal myotomy required for resection
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