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Biomedical subjects

Jacques Marescaux

Publications and source records attributed to Jacques Marescaux.

At least 19 recordsLinked to original sources
PubMed2006

A modular and evolutive component oriented software architecture for patient modeling.

This paper deals with the design aspect of a software aiming at modeling the anatomical and pathological structures of patients from medical images, for diagnosis purposes. In terms of functionalities, it allows to combine image processing algorithms, and to visualize and manipulate 3D models and images. The proposed software uses specific extensible and reusable components and a system managing their combination, thanks to a formal XML-based description of their interfaces. This architecture facilitates the dynamic integration of new functionalities, in particular in terms of image processing algorithms. We describe the structural and behavioral aspects of the proposed reusable component-based architecture. We also discuss the potential of this work for developing other softwares in the field of computer aided surgery.

Computer Simulation↗
PubMed2006

An interactive medical image segmentation system based on the optimal management of regions of interest using topological medical knowledge.

This paper presents an original interactive system for efficient medical image segmentation in computer aided diagnosis. The main originality concerns the method used to manage, according to an a priori topological-based structural model, regions of interest (ROIs) within which computations can be constrained. The goal is then to avoid the processing of irrelevant image points, therefore improving and accelerating segmentations. In the case of a hierarchical modeling procedure, our ROI management method enables, for delineating a given medical structure, to optimally determine image points of interest by taking previously segmented structures into account. We propose a mathematical formulation of the method as well as a possible implementation within an interactive system. We also detail an experience report focussing on the segmentation of several abdominal structures from a CT image. It illustrates the behavior and the potential of our method.

Abdomen↗
PubMed2006

The mechanism of diabetes control after gastrointestinal bypass surgery reveals a role of the proximal small intestine in the pathophysiology of type 2 diabetes.

SUMMARY BACKGROUND DATA: Most patients who undergo Roux-en-Y gastric bypass (RYGB) experience rapid resolution of type 2 diabetes. Prior studies indicate that this results from more than gastric restriction and weight loss, implicating the rearranged intestine as a primary mediator. It is unclear, however, if diabetes improves because of enhanced delivery of nutrients to the distal intestine and increased secretion of hindgut signals that improve glucose homeostasis, or because of altered signals from the excluded segment of proximal intestine. We sought to distinguish between these two mechanisms. METHODS: Goto-Kakizaki (GK) type 2 diabetic rats underwent duodenal-jejunal bypass (DJB), a stomach-preserving RYGB that excludes the proximal intestine, or a gastrojejunostomy (GJ), which creates a shortcut for ingested nutrients without bypassing any intestine. Controls were pair-fed (PF) sham-operated and untreated GK rats. Rats that had undergone GJ were then reoperated to exclude the proximal intestine; and conversely, duodenal passage was restored in rats that had undergone DJB. Oral glucose tolerance (OGTT), food intake, body weight, and intestinal nutrient absorption were measured. RESULTS: There were no differences in food intake, body weight, or nutrient absorption among surgical groups. DJB-treated rats had markedly better oral glucose tolerance compared with all control groups as shown by lower peak and area-under-the-curve glucose values (P < 0.001 for both). GJ did not affect glucose homeostasis, but exclusion of duodenal nutrient passage in reoperated GJ rats significantly improved glucose tolerance. Conversely, restoration of duodenal passage in DJB rats reestablished impaired glucose tolerance. CONCLUSIONS: This study shows that bypassing a short segment of proximal intestine directly ameliorates type 2 diabetes, independently of effects on food intake, body weight, malabsorption, or nutrient delivery to the hindgut. These findings suggest that a proximal intestinal bypass could be considered for diabetes treatment and that potentially undiscovered factors from the proximal bowel might contribute to the pathophysiology of type 2 diabetes.

Animals↗
PubMed2005

Surgical education and Internet-based simulation: The World Virtual University.

The new means and modalities of communication and information technologies have significantly revolutionized access to surgical education. The introduction of the Internet information highway into mainstream clinical practice as an information sharing medium offers a wide range of opportunities to healthcare professionals. High-speed Internet broadcasting allows the display of high-quality full-screen videos. Access to surgical procedures through the Internet already plays a major role in continuing medical education nowadays and will undoubtedly be gaining grounds in the future. WebSurg.com, the World Virtual University, a web-based surgical university, is dedicated to minimally invasive laparoscopic surgery. Using brand-new multimedia data, the electronic university provides thorough descriptions of over 150 procedures in minimal access surgery and 265 videos of surgical interventions. Such a teaching tool recreates all the prerequisites and requirements of a traditional School of Medicine, incorporating the manifold standpoints of world-renowned experts about specific topics and hands-on hints in various surgical specialities. Following the evolution of technologies, recent advances have made it possible to display items of Websurg.com on handheld devices (personal data/digital assistance also known as PDAs, Pocket PCs, and smart phones). Integrating all these elements into a unique World Virtual University, Websurg.com epitomizes the concept of a unified academic center providing teaching and tutorials administered by international experts. The Internet assuredly contributes to the worldwide diffusion of scientific information in an easy and user-friendly way.

Journal Article↗
PubMed2005

The impact of obesity on technical feasibility and postoperative outcomes of laparoscopic left colectomy.

OBJECTIVE: To compare technical aspects and postoperative outcomes of laparoscopic left colectomy in obese and nonobese patients. SUMMARY BACKGROUND DATA: Obesity has been generally associated with increased surgical risk. The data regarding outcomes after laparoscopic colectomy in obese and nonobese patients are limited and quite controversial; however, most reports have suggested that obesity is associated with a greater technical difficulty as well as an increased risk for conversions and postoperative complications. METHODS: All patients undergoing laparoscopic left colectomy for any pathologic condition between January 2001 and January 2003 were analyzed. Patients with a body mass index (BMI) above 30 kg/m were defined as obese and patients with BMI below 30 kg/m were defined as nonobese. Data collected included age, gender, BMI, American Society of Anesthesiologists score, diagnosis, technical parameters of the procedure, operative time, conversion, pathology, length of hospital stay, and complications over a 30-day postoperative course. RESULTS: A total of 123 patients underwent elective laparoscopic left colectomy during the 2-year period. Twelve patients were excluded from analysis because missing data did not allow calculation of their BMI. Of the 111 patients analyzed, 23 (20.7%) were obese and 88 patients (79.3%) were nonobese. Patients' preoperative clinical characteristics were similar in obese and nonobese patients except for BMI (P > 0.001). There were no significant differences between the 2 groups with respect to intraoperative parameters, duration of the operation, resection margin, and number of harvested nodes as well as overall postoperative complication rates. There were no conversions in the obese patients, whereas 5 procedures in the nonobese group required conversion to open surgery (P = not significant). Obese patients had shorter hospital stays than nonobese subjects (7 +/- 2.5 days vs. 9.5 +/- 7 days; P = 0.018). CONCLUSION: In contrast with previously reported series of laparoscopic colectomy, our findings show that obesity does not have an adverse impact on the technical difficulty and postoperative outcomes of laparoscopic left colectomy. Our study supports the safety of using laparoscopic surgery for colorectal diseases in obese patients.

Aged↗
PubMed2005

Laparoscopic total mesorectal excision for rectal cancer surgery.

The introduction of total mesorectal excision in the early 1980s has improved local control and survival in patients with rectal cancer. Laparoscopic resections for colonic malignancies are gaining acceptance in the light of the recent evidence of oncologic adequacy from randomized clinical trials. Technical difficulties and the difference in the natural history of the disease have excluded rectal cancer from major clinical trials comparing laparoscopic to conventional rectal surgery. This review examined the feasibility, safety and oncologic outcomes of reported laparoscopic total mesorectal excision for surgical treatment of operable rectal cancer.

Humans↗
PubMed2005

Late gastric prolapse with pouch necrosis after laparoscopic adjustable gastric banding.

One of the most significant complications of the gastric banding procedure is gastric prolapse. However, pouch necrosis after gastric prolapse is an extremely rare complication. We present the case of a morbidly obese 41-year-old woman who had had a laparoscopic adjustable gastric banding procedure 3 years before. She developed a pouch necrosis after a late gastric prolapse. After failure of conservative treatment, a diagnostic laparoscopy was performed. This resulted in removal of the band and the diagnosis of pouch necrosis. A laparotomy was indicated and a sleeve gastrectomy was performed. A delay in the diagnosis of gastric prolapse can lead to major complications. Initial referral to a specialized center is necessary for proper care of this complication. Failure of conservative treatment mandates early operative intervention.

Adult↗
PubMed2005

Real-time ultrasonography simulator based on 3D CT-scan images.

A new method for real-time simulation of ultrasonography is presented. This method uses directly 3D enhanced helical CT-scan images. The originality of this method is that it can be run directly on real patient data with no need of any pretreatment.

Computer Simulation↗
PubMed2004

The role of the small bowel in the regulation of circulating ghrelin levels and food intake in the obese Zucker rat.

Circulating levels of ghrelin, a stomach peptide that promotes food intake, rise before and fall after meal. We aimed to investigate whether there is an independent contribution of the small bowel to the regulation of ghrelin and appetite. A duodenal-jejunal bypass (DJB) with preservation of normal gastric volume and exposure to nutrients was performed in 12-wk-old obese Zucker ZDF fa/fa rat. Food intake, weight gain, 48-h fasting, and 24-h refeeding levels of total and acylated ghrelin were measured. The DJB was challenged against gastric banding (GB), diet, and a sham operation in matched animals. Normal controls were age-matched Wistar rats, which underwent either DJB or a sham operation. The Zucker obese animals showed a paradoxical increase of acylated ghrelin levels after refeeding (+30% with respect to fasting levels; P = 0.001), an abnormality that was completely reversed only by the DJB (-30%; P = 0.01) but not after GB, diet, or sham operation. In obese rats, the DJB resulted in significantly less food intake and weight gain compared with both GB (P < 0.05) and sham operation (P < 0.01). In sharp contrast, the DJB did not alter food intake and weight gain in normal rats. The DJB does not physically restrict the flow of food but restores meal-induced suppression of acylated ghrelin and significantly reduces food intake in Zucker obese rats. These findings suggest an independent intestinal contribution to the regulation of the dynamic ghrelin response to eating and the possibility that defective signaling from the proximal bowel could be involved in the pathogenesis of obesity/hyperphagia.

Anastomosis, Roux-en-Y↗
PubMed2004

Safe laparoscopic surgery in the elderly.

BACKGROUND: The elderly are more prone to complications of surgery because of comorbidity, and they may benefit most from a minimally invasive approach. This study was intended to evaluate the safety of the use of a laparoscopic approach for emergency and elective surgery in elderly patients. METHODS: From January 2000 to June 2001, all patients over 75 years of age who underwent a procedure that began laparoscopically were included. Physiologic and operative scores according to the POSSUM scoring system were recorded. These were then used to calculate predicted morbidity and mortality by both the POSSUM and P-POSSUM systems. Predicted outcomes were compared with actual outcomes. RESULTS: One hundred sixty-two patients with a mean age of 80 years were included; 52% were emergency cases. The overall morbidity was 14.5% and the mortality rate was 1.8%. Fourteen procedures (8.4%), all emergencies, were converted. Both mortality and morbidity rates were lower than the predicted values (P = 0.001 and P = 0.0001, respectively). CONCLUSIONS: A laparoscopic approach can be used safely in an elderly population undergoing surgery in a daily practice for miscellaneous conditions, whether elective or emergency operations.

Age Factors↗
PubMed2004

Combined suicide gene therapy for pancreatic peritoneal carcinomatosis using BGTC liposomes.

Peritoneal dissemination is a common end-stage complication of pancreatic cancer for which novel therapeutic modalities are actively investigated, as there is no current effective therapy. Thus, we evaluated, in a mouse model of pancreatic peritoneal carcinomatosis, the therapeutic potential of a novel nonviral gene therapy approach consisting of bis-guanidinium-tren-cholesterol (BGTC)-mediated lipofection of a combined suicide gene system. Human BxPC-3 pancreatic cells secreting the carcinoembryonic antigen (CEA) tumor marker were injected into the peritoneal cavity of nude mice. After 8 days, intraperitoneal (i.p.) lipofection was performed using BGTC/DOPE cationic liposomes complexed with plasmids encoding the two prodrug-activating enzymes Herpes Simplex Virus thymidine kinase and Escherichia coli cytosine deaminase, the latter being expressed from a bicistronic cassette also encoding E. coli uracil phosphoribosyltransferase. Administration of the lipoplexes was followed by treatment with the corresponding prodrugs ganciclovir and 5-fluorocytosine. The results presented herein demonstrate that BGTC/DOPE liposomes can efficiently mediate gene transfection into peritoneal tumor nodules. Indeed, HSV-TK mRNA was detected in tumor nodule tissues by semiquantitative reverse transcription-polymerase chain reaction analysis. In addition, green fluorescent protein (GFP) fluorescence and X-gal staining were observed in the peritoneal tumor foci following lipofection of the corresponding EGFP and LacZ reporter genes. These expression analyses also showed that transgene expression lasted for about 2 weeks and was preferential for the tumor nodules, this tumor preference being in good agreement with the absence of obvious treatment-related toxicity. Most importantly, mice receiving the full treatment scheme (BGTC liposomes, suicide genes and prodrugs) had significantly lower serum CEA levels than those of the various control groups, a finding indicating that peritoneal carcinomatosis progression was strongly reduced in these mice. In conclusion, our results demonstrate the therapeutic efficiency of BGTC-mediated i.p. lipofection of a combined suicide gene system in a mouse peritoneal carcinomatosis model and suggest that BGTC-based prodrug-activating gene therapy approaches may constitute a potential treatment modality for patients with peritoneal carcinomatosis and minimal residual disease.

Animals↗
PubMed2004

Effect of duodenal-jejunal exclusion in a non-obese animal model of type 2 diabetes: a new perspective for an old disease.

BACKGROUND: The Roux-en-Y gastric bypass and the biliopancreatic diversion effectively induce weight loss and long-term control of type 2 diabetes in morbidly obese individuals. It is unknown whether the control of diabetes is a secondary outcome from the treatment of obesity or a direct result of the duodenal-jejunal exclusion that both operations include. The aim of this study was to investigate whether duodenal-jejunal exclusion can control diabetes independently on resolution of obesity-related abnormalities. METHODS: A gastrojejunal bypass (GJB) with preservation of an intact gastric volume was performed in 10- to 12-week-old Goto-Kakizaki rats, a spontaneous nonobese model of type 2 diabetes. Fasting glycemia, oral glucose tolerance, insulin sensitivity, basal plasma insulin, and glucose-dependent-insulinotropic peptide as well as plasma levels of cholesterol, triglycerides, and free fatty acids were measured. The GJB was challenged against a sham operation, marked food restriction, and medical therapy with rosiglitazone in matched groups of animals. Rats were observed for 36 weeks after surgery. RESULTS: Mean plasma glucose 3 weeks after GJB was 96.3 +/- 10.1 mg/dL (preoperative values were 159 +/- 47 mg/dL; P = 0.01). GJB strikingly improved glucose tolerance, inducing a greater than 40% reduction of the area under blood glucose concentration curve (P < 0.001). These effects were not seen in the sham-operated animals despite similar operative time, same postoperative food intake rates, and no significant difference in weight gain profile. GJB resulted also in better glycemic control than greater weight loss from food restriction and than rosiglitazone therapy. CONCLUSIONS: Results of our study support the hypothesis that the bypass of duodenum and jejunum can directly control type 2 diabetes and not secondarily to weight loss or treatment of obesity. These findings suggest a potential role of the proximal gut in the pathogenesis the disease and put forward the possibility of alternative therapeutic approaches for the management of type 2 diabetes.

Anastomosis, Surgical↗
PubMed2004

Three-dimensional virtual cholangioscopy: a reliable tool for the diagnosis of common bile duct stones.

OBJECTIVE: Our goal was to evaluate the clinical reliability of a new software system employing 3-dimensional (3D) virtual anatomic reconstruction and intraluminal virtual exploration for detection of choledocholithiasis and preoperative visualization of the biliary anatomy. SUMMARY BACKGROUND DATA: Virtual reality systems have been proposed for gastroscopy, bronchoscopy, and colonoscopy, as well as for the 3D reconstruction of liver anatomy and hepatic lesions. The impact of these systems in preoperative diagnostics has not been established due to the lack of large clinical series evaluating their reliability. METHODS: From November 2000 to July 2002, all patients presenting to our Institute with suspected choledocholithiasis were prospectively included in the study. All patients underwent conventional magnetic resonance cholangiopancreatography (MRCP) and either intraoperative cholangiogram (IOC) or endoscopic retrograde cholangiopancreatography (ERCP). The digital data from MRCP were incorporated into an original virtual reality software system to generate a 3D reconstruction. All 3D reconstructions were evaluated by a surgeon and a computer software engineer who were blind to the results of the IOC or ERCP. Sensitivity and specificity were then calculated based on the results of either the IOC or ERCP. RESULTS: Sixty-five patients were enrolled in the study. The average time required to reconstruct the images into navigable virtual reality was 7.5 minutes (range, 4-13.5). The 3D virtual cholangioscopy had sensitivity and specificity rates of 71% and 91%, respectively, compared with 61% and 86% of the standard MRCP. CONCLUSION: : The 3D virtual cholangioscopy provides detailed preoperative reconstruction of biliary anatomy and reliable identification of choledocholithiasis with acceptable sensitivity and specificity in a clinical setting. Newer software developments may further enhance its accuracy, so that virtual cholangioscopy might challenge or replace more invasive diagnostic measures in the near future.

Cholangiography↗
PubMed2004

Image-guided robotic surgery.

Medical image processing leads to an improvement in patient care by guiding the surgical gesture. Three-dimensional models of patients that are generated from computed tomographic scans or magnetic resonance imaging allow improved surgical planning and surgical simulation that offers the opportunity for a surgeon to train the surgical gesture before performing it for real. These two preoperative steps can be used intra-operatively because of the development of augmented reality, which consists of superimposing the preoperative three-dimensional model of the patient onto the real intraoperative view. Augmented reality provides the surgeon with a view of the patient in transparency and can also guide the surgeon, thanks to the real-time tracking of surgical tools during the procedure. When adapted to robotic surgery, this tool tracking enables visual serving with the ability to automatically position and control surgical robotic arms in three dimensions. It is also now possible to filter physiologic movements such as breathing or the heart beat. In the future, by combining augmented reality and robotics, these image-guided robotic systems will enable automation of the surgical procedure, which will be the next revolution in surgery.

Humans↗
PubMed2004

Robot-assisted remote surgery: technological advances, potential complications, and solutions.

Technical limitations, mostly related to the issue of time delay for transmission of digitized information, had prevented the development of remote surgery intended as performance of a complete surgical procedure from long distances. To overcome the issue of time delay, tests and researches performed with the joined effort of surgeons, robotic and telecommunication engineers convinced our group that use of the high-speed terrestrial network [asynchronous transfer mode (ATM) service], rather than satellite connections, would significantly reduce the time lag for transmission of data. Using ATM technology, our group demonstrated the feasibility of performing surgery across transoceanic distances by safely carrying out a laparoscopic cholecystectomy, first on an animal model and later (September 7, 2001), on a patient. Using ATM technology, the mean time lag for transmission of data and images was 155 msec despite a total round-trip distance of 14,000 km. Teletransmission of active surgical manipulations have the potential to ensure availability of surgical expertise in remote locations for difficult or rare operations, and improve surgical training worldwide. However, several limitations remain for remote surgery to become commonplace. Among these, the need to render ATM network available to hospitals, costs of technology, ethical and liability issues, and possible conflicts of jurisdictions between countries involved.

Animals↗
PubMed2004

Argonaute 3D: a real-time cooperative medical planning software on DSL network.

Today, diagnosis of cancer and also therapeutic choice imply many specialized practitioners. They are generally located at different places and have to take the best decision as promptly as possible with the difficulty of CT-scan or MRI interpretation. Argonaute 3D is a tool that easily overcomes these issues, thanks to a cooperative solution based on virtual reality. An experimentation, where four practitioners met virtually throughout France, allowed to assess the interest of this solution.

Computer Communication Networks↗
PubMed2004

[Total mesorectal excision by laparoscopy for rectal cancer].

The treatment of rectal cancer has improved mostly because of the emergence of total mesorectal excision (TME), first described by Heald, and the adjunct of adjuvant therapy in the form of radiotherapy and chemotherapy. Laparoscopy has now been performed for more than a decade with results showing faster return to activity and decreased postoperative pain for intra-abdominal surgery. Laparoscopy is now widely used and is well accepted for the treatment of most intra-abdominal benign pathologies. Furthermore, several authors now report excellent short and medium-term results for the treatment of colorectal cancer. These study tends to show that laparoscopy can be safely applied to digestive malignancies, when oncological principles specific to laparoscopy are respected. The laparoscopic approach is in our opinion a perfect approach for the performance of TME, because of the magnification of structures that it provides, and allows the surgeon to see important structures that need to be identified for the performance of the best oncological and functional procedure possible. This paper describes in a through manner our standardized technique. We also review our own experience with laparoscopic TME, the multimodal treatment of rectal cancer, and provide an analysis of the literature about TME when performed by laparotomy and laparoscopy.

Clinical Trials as Topic↗