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Biomedical subjects

Y M Dion

Publications and source records attributed to Y M Dion.

At least 19 recordsLinked to original sources
PubMed2001

Totally laparoscopic abdominal aortic aneurysm repair.

Abdominal aortic aneurysm (AAA) resection is a major surgical procedure performed frequently. As a minimal access procedure, laparoscopy has been shown in the field of general surgery to improve a patient's postoperative well-being and to shorten hospital stay. The same benefits could be expected from a laparoscopic approach for AAA repair. We report what we believe to be the first totally laparoscopic AAA repair performed according to the principles of endoaneurysmorrhaphy.

Aged↗
PubMed2000

Sealing of polyester prostheses with autologous fibrin glue and bone marrow.

The purpose of this study was to develop a sealing technique for polyester prosthetic grafts able to promote healing and reduce intimal hyperplasia. The porcine experimental model was aortoiliac bypass with a 6-mm diameter knitted polyester prosthetic graft implanted for 14 and 90 days. Animals were divided into three groups according to sealing technique as follows: pre-clotting with blood (group I, n = 12), sealing with autologous fibrin glue (group II, n = 14), and sealing with autologous fibrin glue and bone marrow cells (group III, n = 16). Feasibility and quality of sealing were evaluated by scanning electron microscopy prior to implantation and by assessment of blood loss. After removal, prostheses were cut into three segments comprising the proximal anastomosis, midsection, and distal anastomosis. Pieces were fixed, embedded in paraffin, and serially sectioned for histologic study. Histological study focused on the degree of stenosis and hyperplasia of the neointima of each prosthesis. The results of this short-term study indicate that sealing of polyester vascular prosthetic grafts with autologous fibrin glue and bone marrow cells is effective in reducing intimal hyperplasia. However further study will be needed to assess long-term healing.

Animals↗
PubMed2000

Endovascular procedures under near-real-time magnetic resonance imaging guidance: an experimental feasibility study.

PURPOSE: The purpose of this study was to assess the feasibility of insertion of endovascular stents and the precision of an open-field interventional magnetic resonance imaging (iMRI) system in an in vivo model. METHODS: A feasibility study was undertaken at a university-affiliated hospital. Three male piglets with an average age of 6 months and a weight between 70 and 77 kg and two 3-month-old male piglets that weighed 40 to 44 kg were anesthetized. The five piglets underwent placement of nitinol stents inserted through the right femoral artery, under the guidance of a SIGNA-SP 0. 5T open-configuration iMRI unit. With a dedicated high-resolution near-real-time MRI sequence, the stent was guided and deployed onto a predefined target. RESULTS: The main outcome measures were the duration of the procedure from the beginning of positioning to the end of deployment of the stent, the final position of the stent in relation to the target on the iMRI screen, and comparison with autopsy findings. Three stents were deployed within the aorta at the level of the renal arteries, and two were deployed within the right iliac artery just below the aortic trifurcation. The average duration of the endovascular deployment was 13 minutes. There was an agreement of 0.6 mm in the position of the stent as observed on iMR images and found at autopsy. When the piglets were sacrificed, the average distance between the stents and the predefined target was 7. 8 mm, mostly because of the migration of one stent. Axial views allowed for accurate determination of stent impaction on the vascular wall. CONCLUSIONS: This study confirms the feasibility of stent deployment under near-real-time MRI guidance. It also emphasizes some inherent characteristics that hold promise with regard to other conventional techniques: stents and vascular structures are visualized in near-real-time in any desired plane, and the technique is performed without the potential adverse effects of ionizing radiations and iodinated contrast agents.

Animals↗
PubMed2000

In vitro evaluation of the accuracy of open-configuration MRI in endovascular techniques.

The purpose of this study was to determine the accuracy of an interventional magnetic resonance imaging (iMRI) system to position an endovascular catheter in an in vitro model that simulated an infrarenal aortic aneurysm. Adequate visualization of abdominal aortic aneurysms (AAAs) was shown previously in humans. A dedicated near-real-time imaging protocol readily available on a Signa SP 0.5T open configuration MRI unit (General Electric Medical Systems, Milwaukee, WI, USA) was used to image the AAAs of ten human volunteers. A pulsatile in vitro model that simulated an AAA was built, which included the kidneys, the renal arteries, the aorta, and the iliac arteries. A catheter was advanced to a predetermined target through one of the iliac limbs of the model. Using two different techniques, the accuracy with which an interventionist could position the endovascular catheter under the near-real-time guidance of the iMRI system was evaluated. The AAAs of all ten patients were visualized, including the aneurysm wall, the thrombus within it, and the residual lumen, while maintaining adequate contrast, signal, and imaging speed. The position of the catheter was evaluated on target in 42 in vitro procedures. This series of tests showed an average accuracy of 1 mm for catheter positioning. The near-real-time imaging mode of the iMRI system enabled satisfactory evaluation of human AAAs, and it showed great accuracy for catheter positioning in the in vitro model. These results provide optimism regarding the potential of iMRI in endovascular surgery.

Aortic Aneurysm, Abdominal↗
PubMed1999

Laparoscopic end-to-end aortobifemoral bypass with reimplantation of the inferior mesenteric artery. An experimental study.

BACKGROUND: Colic ischemia is a serious complication that can occur after abdominal aortic surgery. It has been described in two patients after laparoscopic aortic surgery. The goal of the current experiment was to determine the feasibility of inferior mesenteric artery (IMA) reimplantation during laparoscopic aortobifemoral bypass (LAFB). METHODS: Six piglets were submitted to the laparoscopic approach according to the "apron" technique previously described. The infrarenal aorta was clamped and an LAFB was performed using a dacron graft. The IMA was reimplanted in the body of the graft with a running 5-0 polypropylene suture. RESULTS: Mean operation and dissection times were 282.5 min (range, 270-310 min) and 123 min (range, 110-140 min), respectively, with a mean blood loss of 108 ml (range, 80-150 ml). Aortic clamping and anastomotic times were 123 min (range, 110-135 min) and 33 min (range, 24-45 min), respectively. The IMA reimplantation took 55 min (range, 45-70 min). At autopsy, all anastomoses were patent with no stenosis nor leak. CONCLUSION: Laparoscopic IMA reimplantation during laparoscopic aortobifemoral bypass is feasible.

Anastomosis, Surgical↗
PubMed1999

A model for laparoscopic aortic aneurysm resection.

BACKGROUND: The laparoscopic treatment of abdominal aortic aneurysm (AAA) could improve the perioperative course of patients suffering from this disease. The goal of the current experiment was to develop an animal model that could simulate many of the difficulties encountered in the treatment of human AAA. METHODS: Twelve piglets were submitted to a laparotomy. An AAA was created by suturing a 12- by 5-cm piece of knitted dacron to an aortotomy. Four to 15 days later, the piglets underwent the laparoscopic treatment of their AAA. RESULTS: All procedures were completed successfully. The average duration of the laparoscopic intervention was 210 min (range, 150-300 min). Aortic cross-clamping took 55 min (range, 38-72 min). Blood loss averaged 150 ml (range, 80-250 ml). During each procedure, four to six lumbar arteries were treated by intraluminal aortic clip application. Intraoperative complications consisted of one splenic trauma, one anastomotic stenosis, and one case of bleeding from a lumbar vein. CONCLUSION: Laparoscopic AAA resection is feasible in this animal model, which presents similarities to human AAA.

Anastomosis, Surgical↗
PubMed1999

Fat- and bone marrow-impregnated small diameter PTFE grafts.

OBJECTIVES: to evaluate an alternative and simple technique which consists in impregnation of a synthetic prosthesis with either autogenic omental fat or bone marrow. These tissues have been selected based on previous works and because they contain multiple cellular and extracellular compounds with biological healing properties (i.e. angiogenesis, endothelialisation, etc.). DESIGN: PTFE grafts of Group 1 were impregnated with fatty tissue, those of Group 2 with bone marrow and those of Group 3 served as controls. MATERIALS: nine mongrel dogs divided among these three groups. PTFE grafts are 3 mm in diameter. METHODS: in each animal, both iliac arteries were submitted to an end-to-side ilio-iliac bypass. At 3 months, pathology assessment was performed. RESULTS: group 1: all grafts were thrombosed and intimal hyperplasia was found occluding the anastomotic sites. Group 2: 4/6 grafts were patent and their mid-portion presented a thin neointima which did not totally cover the anastomotic sites. Group 3: 2/5 grafts were patent and their mid-portion as well as the anastomotic sites were covered with neointima which was hyperplastic in some areas. CONCLUSIONS: addition of bone marrow cells may contribute to improve the quality of the healing process.

Adipose Tissue↗
PubMed1999

Technological advances in laparoscopic aorto-occlusive surgery.

Minimally invasive surgery (MIS) has been recognized as increasingly beneficial to patients undergoing various cardiovascular surgical procedures. Cardiac applications with MIS techniques and technologies are being shown as beneficial in heart valve replacement and in coronary artery bypass. In vascular surgery, benefits are being reported for endoscopic saphenous vein harvesting as well as endoscopic ligation of incompetent perforators. Since 1993, applications of laparoscopy to aortic surgery have been reported. Until these reports, percutaneous interventional procedures have been the mainstay of MIS vascular work for aortoiliac disease. Reported laparoscopic techniques have ranged from laparoscopically assisted techniques to procedures performed completely laparoscopically. Several studies show that laparoscopic aortic surgery is feasible. These show the known advantages of MIS for patients, with decreased use of analgesics, shortened ileus, earlier ambulation, and shortened length of stay. Laparoscopy has been showing a growing role in the armamentarium of the modern vascular surgeon.

Adult↗
PubMed1999

Experimental laparoscopic aortobifemoral bypass with end-to-side aortic anastomosis.

The goal of this animal experiment was to demonstrate the feasibility of laparoscopic end-to-side aortic anastomosis, which is mandatory in certain cases presenting with aortoiliac occlusive disease. Six piglets were submitted to laparoscopic approach of the aortoiliac vessels using the "apron" technique. After clamping the infrarenal aorta with a laparoscopic Satinsky clamp, a 3-cm end-to-side laparoscopic aortic anastomosis was constructed. Mean operative and dissection times were 198 (170-240) and 92 (75-105) min, respectively, with a mean blood loss of 86 (50-120) mL. Mean preoperative and postoperative hematocrits were 38 (3448) and 38 (34-46). Aortic cross-clamp and anastomotic times were 51 (40-65) and 44 (35-60) min, respectively. No extra sutures were needed to secure the anastomoses. At autopsy, all the anastomoses were patent without stenoses. Results indicate the feasibility of laparoscopic aortobifemoral bypass with an end-to-side aortic anastomosis.

Anastomosis, Surgical↗
PubMed1998

Totally laparoscopic aortobifemoral bypass: a review of 10 patients.

The main purpose of this study is to evaluate the feasibility of totally laparoscopic aortobifemoral bypass for occlusive aortoiliac disease. Ten patients who had incapacitating claudication have been included to date in this investigation. We have designed a transabdominal retroperitoneal technique that allows performance of the procedure without the problems associated with retraction of intraperitoneal organs. During the study, surgery time decreased from 510 to 245 min. Mean total aortic clamping time was 121 min, and the mean time required to perform the aortic anastomosis was 66 min. Mean blood loss was 820 ml. Three patients needed conversion. Postoperative complications developed in three patients. One had an aortoureteral fistula, which needed reoperation; one experienced complications related to a retroaortic left renal vein; and the third had a mild compartment syndrome of the right leg. Totally laparoscopic aortobifemoral bypass is feasible. Laparoscopic aortobifemoral bypass appears to ease the patient's postoperative course and could become in the not so distant future part of the repertoire of the surgeon performing vascular surgery.

Adult↗
PubMed1997

Visual integration of data and basic motor skills under laparoscopy. Influence of 2-D and 3-D video-camera systems.

BACKGROUND: The qualities of visual perception and of motor reaction to the visual stimulus have never been studied in reference to the type of video-camera system (2-D vs 3-D) used during laparoscopy. METHODS: The study was designed in two parts. The first evaluated the ability of the eye to discriminate how objects are spaced relative to one another. The second investigated the motor reaction to the visual stimulus in an environment where depth was the preponderent cue. The tests were performed in a pelvi-trainer in which were inserted different modules built either for visual observation (Part 1) or for evaluation of motor ability (Part 2). Variables studied during Part 1 were the time required to do the test and the number of errors committed during its performance. The variable evaluated during Part 2 was the time needed to terminate the test. Each of these two parts of the study were completed alternating the 2-D and 3-D systems. A total of 304 observations were recorded. Statistics used were the paired t-test, the independent group t-test, and the Newman-Keuls multiple comparisons test. RESULTS: Results of Part 1 of the study confirm that visual perception varies significantly among individuals (n = 10) (p < 0.05) and that a true 3-D video-camera system facilitates visual perception when compared to a 2-D system (p < 0.001). Results of Part 2 of the study also show significant differences among participants (n = 9)(p < 0.05). The true 3-D system allowed significantly faster motor performances than the 2-D system (p < 0.001). CONCLUSION: Our experiment shows that the 3-D system allowed significant improvements in the execution of the evaluated parameters. Also noted were significant differences among participants in term of visual and motor skills.

Humans↗
PubMed1997

A new technique for laparoscopic aortobifemoral grafting in occlusive aortoiliac disease.

PURPOSE: This article describes an original laparoscopic technique that allows performance of aortobifemoral bypass grafting. METHODS: The technique described is the result of 6 years of in vitro and animal experimentation. It also represents the end result of prior clinical research with laparoscopy-assisted aortoiliac surgery and totally laparoscopic retroperitoneal aortobifemoral bypass grafting. The technique consists of the creation of a flap of retroperitoneum that is used to separate the intraperitoneal organs from the content of the retroperitoneal cavity. Surgery can then be conducted with no intrusion of any intraabdominal organ into the operative field. Another advantage is that the pneumoperitoneum is equally distributed among the two cavities. A conventional aortobifemoral bypass procedure is then performed with laparoscopic instrumentation. RESULTS: The described technique has been performed in three patients to date. The patients' intraoperative blood loss did not exceed 500 ml, and no complication arose. The intraoperative need for crystalloids was of the order of 3 L (almost half the quantity usually administered). The patients' analgesia requirement was low in these patients, and return to walking was rapid. They were sent home between the fourth and sixth postoperative days. CONCLUSIONS: The innovative technique described here is safe and appears to ease the patient's postoperative course. Data recovered from the multicenter study, which is now in its preliminary phase, should help answer numerous questions. We expect the procedure to be reproducible in other university centers that are participating in the trial.

Aorta, Abdominal↗
PubMed1996

Laparoscopic inguinal herniorrhaphy: appraisal of a cohort study.

OBJECTIVES: To assess the safety and effectiveness of individualized laparoscopic herniorrhaphy and to compare its intraoperative cost to that of the standard Bassini operation. DESIGN: An analytic cohort study. SETTING: A university teaching hospital. PATIENTS: One group of 158 patients underwent 167 laparoscopic herniorrhaphies for symptomatic groin hernias. The approach was transabdominal preperitoneal for the first 124 patients and totally preperitoneal for the last 34 patients. A second group of 50 patients underwent a conventional Bassini operation. INTERVENTION: Individualized laparoscopic inguinal herniorrhaphy or Bassini herniorrhaphy. MAIN OUTCOME MEASURES: Complications and recurrences encountered in the laparoscopic group. Total operative time and intraoperative cost involved in both procedures. Analgesia required in each group during the first 2 postoperative days. RESULTS: Intra- and postoperative complications of the laparoscopic approach were not life threatening. The recurrence rate at a mean follow-up of 16.8 months was 1.2%. Total operative time was significantly (p < 0.001) longer in the laparoscopy group than in the Bassini group. Patients in the Bassini group took more parenteral analgesics than those in the laparoscopy group (p = 0.02), but there was no difference with respect to the number of times enteral analgesics were required (p = 0.32). Use of mesh and staples was more expensive than sutures alone inserted laparoscopically. The Bassini procedure was a less expensive procedure than laparoscopic herniorrhaphy. CONCLUSIONS: The laparoscopic treatment of groin hernias is safe. The recurrence rate is low. Primary unilateral inguinal hernias could be adequately treated at a lesser cost by a standard approach. Bilateral, recurrent and femoral hernias could benefit from a laparoscopic approach.

Adult↗
PubMed1996

Experimental laparoscopic aortic aneurysm resection and aortobifemoral bypass.

The purpose of the present study was to develop a technique for laparoscopic aortic aneurysm resection and aortobifemoral bypass through an anterior retroperitoneal approach. Eight piglets weighing between 75 and 80 kg were anesthetized. The concepts of Shumacker's anterior retroperitoneal exposure of the aorta were modified to allow laparoscopic exposure of the aorta in the first four animals. The other four animals were treated as if they had an aortic aneurysm. The piglet is placed in a supine position. The first port (1.5 cm) is placed laterally near the tip of the 12th rib. As much dissection of the retroperitoneum as possible is performed digitally through this port. A second port (1.5 cm), through which an abdominal lift device and a peritoneal retractor will be inserted, is created superiorly just lateral to the left rectus sheath, and a plane is developed that joins the original dissected space. Two other ports (1.5 cm) are placed in the flanks in a plane inferosuperior to the first port. The surgeon will use two of the lateral ports, and the third one is for the laparoscope. The last two ports (1.5 cm), from which the assistant will work, are placed in the left paramedian region. Using this approach, we performed four aortobifemoral bypasses in an average of 4.5 h after conventional i.v. heparinization (100 IU/kg) with minimal bleeding (blood loss < 550 cc). After infrarenal aortic cross-clamping, the external iliac and caudal vessels were either tied with 0-chromic or occluded with laparoscopic bull-dogs. The aorta was opened, and bleeding lumbar arteries and the aortoiliac junction were sutured with 4-0 Prolene. The vascular graft was sutured end-to-end to the aortic stump with running 4-0 Prolene. Tunneling to the femoral regions was made easy by the position of the animal. No mortality occurred before sacrifice of the animals. This laparoscopic animal model paves the way for human aortic aneurysm replacement.

Animals↗
PubMed1996

Experimental laparoscopic aortobifemoral bypass for occlusive aortoiliac disease.

OBJECTIVE: To describe a totally laparoscopic technique for aortobifemoral bypass to treat aortoiliac atheromatous occlusive disease. DESIGN: A feasibility study. SETTING: A university teaching hospital. SUBJECTS: Six piglets weighing between 70 and 80 kg were submitted to a totally laparoscopic retroperitoneal aortobifemoral bypass, performed through six trocar sites, with abdominal suspension and a gasless technique. No minilaparotomy was performed. After systemic heparinization, the infrarenal aorta was cross-clamped and the aortic bifurcation stapled. An end-to-end aorto-prosthetic anastomosis was performed. Retroperitoneal tunnels were created to allow each limb of the graft to join its corresponding femoral artery by a conventional anastomosis. INTERVENTION: Totally laparoscopic aortobifemoral bypass. MAIN OUTCOME MEASURES: Duration of the procedure, intraoperative blood loss and operative complications, bleeding in the immediate postoperative period. Evaluation of the aortic anastomosis at autopsy. RESULTS: All aortobifemoral bypasses were completed in less than 4 hours. Intraoperative blood loss did not exceed 250 mL. No intraoperative complication was encountered except occasional bleeding at the aortic anastomosis upon releasing the arterial clamp. This was controlled with a collagen sponge (three cases) or extra stitches (two cases). The animals were observed for 15 minutes before sacrifice. Autopsy revealed a normal aortic anastomosis in all cases and a normal progression of the limbs of the graft under the ureters in the retroperitoneal tunnels. CONCLUSIONS: This animal model demonstrates the feasibility of the aortobifemoral bypass through a laparoscopic approach. The retroperitoneal anatomy of the piglet is similar to that of man. Aortic surgery can be conducted as for the standard technique. We used a similar approach to perform the first human, totally laparoscopic aortobifemoral bypass with an end-to-end anastomosis.

Anastomosis, Surgical↗
PubMed1995

Experimental carbon dioxide pulmonary embolization after vena cava laceration under pneumoperitoneum.

The potential for pulmonary embolization following major venous laceration occurring during laparoscopic surgery has never been evaluated. Five anesthetized dogs were hemodynamically monitored with an arterial line and Swan-Ganz catheter. Observation by transesophageal echocardiography (TEE) allowed comparison with pulmonary artery pressure (PAP) recording. Under pneumoperitoneum, a 1-cm venotomy was performed in the infrarenal vena cava and a total of 11 events were evaluated upon unclamping the venotomy. These results were compared with intravenous (i.v.) bolus injections of 15 cc of CO2 (15 events) and of 100 cc of CO2 (12 events). The animals were maintained euvolemic. In 2 out of the 11 (18%) events which followed unclamping the venotomies, a few CO2 bubbles were seen in the right heart cavities. However, the quantity of gas was much less important than that seen after i.v. injection of 15 cc and 100 cc of CO2. There was no significant elevation of the PAP from pre-event values after venotomy or after i.v. injection of 15 cc of CO2. However, there was a significant difference (P < 0.05) when these results were compared to the PAP values recorded after i.v. injection of 100 cc of CO2. No dog died after these episodes of embolization. Massive i.v. injection of CO2 (> 300 cc) led to appearance of gas bubbles in the left heart cavities and death. This experiment suggests that caution should be exerted when laparoscopic surgery is performed beside large veins. Nevertheless, the observation that no gas embolism occurred in 82% of the cases after unclamping venotomies was unexpected. In contrast, many more gas bubbles were detected in the right heart after i.v. injection of only 15 cc of CO2. TEE is a more sensitive indicator of pulmonary embolization than elevation of PAP.

Animals↗