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At least 1,117 records · Page 62Linked to original sources
PubMed1998

A PC-based surgical simulator for laparoscopic surgery.

Surgical simulators for minimally invasive surgery have been developing in the 1990s. Most of them use high-end UNIX workstations for real-time simulation of complex human organ models. Only few of them have input devices with force feedback. Recently, personal computer technologies have made real-time display of relatively complex models feasible. We are developing an Intel-based laparoscopic surgical simulator that provides near real-time intuitive interaction between the trainee and simulated models of human organs. The surgical simulator has a prototypical scenario of cholecystectomic surgery. It can interactively simulate the deformation and cutting of cystic duct and vein. In addition, a set of input devices with force feedback has been designed and tested to imitate the manipulation of surgical instruments. The input device has five degrees of freedom and three of them are driven by DC motors to produce force feedback.

Cholecystectomy↗
PubMed2005

[Sensor-based detection of skull positioning for image-guided cranial navigation under free head mobility].

PURPOSE: Although computer- and image-guided surgical procedures are an improvement of frame-guided stereotaxy, many navigation systems still require rigid fixation of the patient's head throughout the operation. This study describes the clinical application of a technical modification that enables cranial navigation with "free head mobility" using CT and MR images as well as the calculated 3-D reconstruction models. MATERIAL AND METHODS: A sensor-based electromagnetic neuronavigation system was expanded to allow the localization and position monitoring of several sensors within an electromagnetic field. One of these sensors was attached to a dental splint as an additional reference (DRF = dynamic reference frame). Thus, it was possible to determine the position of the sensor-guiding surgical instruments and to record the slightest movement of the cranium as well. This information was then used to continuously adapt the position of the imaging plane and the resultant calculated 3-D reconstructions to the actual position of the cranium. RESULTS: The clinical application of the DRF was tested for different neurosurgical procedures. They included image-guided biopsies and endoscopic interventions using MRI data, transnasal accesses to the base of the skull using CT data and surgical removal of multilocular metastases using data from both imaging modalities. Intracranial target reference points as well as those on the skull were found with a high accuracy to the initial measurement position after arbitrary movement of the patient's head. Thus, navigation was also possible without rigid fixation of the head because of the continuous adaptation of the imaging data on the change in position of the patient's head. CONCLUSION: Based on these first test results, a high clinical potential for DRF application in cranial navigation is to be expected. The aim of DRF is to dispense with the rigid fixation of the patient's head. This increases the application scope of image-guided navigation procedures to include, for example, any bioptic or endoscopic intervention, in which rigid pin fixation of the cranium is not required or desired. For all other procedures, continuous position monitoring by DRF ensures automatic correction of imaging data with mechanical alteration of the head position.

Brain Diseases↗
PubMed2006

In silico models of acute inflammation in animals.

Trauma and hemorrhagic shock elicit an acute inflammatory response, predisposing patients to sepsis, organ dysfunction, and death. Few approved therapies exist for these acute inflammatory states, mainly due to the complex interplay of interacting inflammatory and physiological elements working at multiple levels. Various animal models have been used to simulate these phenomena, but these models often do not replicate the clinical setting of multiple overlapping insults. Mathematical modeling of complex systems is an approach for understanding the interplay among biological interactions. We constructed a mathematical model using ordinary differential equations that encompass the dynamics of cells and cytokines of the acute inflammatory response, as well as global tissue dysfunction. The model was calibrated in C57Bl/6 mice subjected to (1) various doses of lipopolysaccharide (LPS) alone, (2) surgical trauma, and (3) surgery + hemorrhagic shock. We tested the model's predictive ability in scenarios on which it had not been trained, namely, (1) surgery +/- hemorrhagic shock + LPS given at times after the beginning of surgical instrumentation, and (2) surgery + hemorrhagic shock + bilateral femoral fracture. Software was created that facilitated fitting of the mathematical model to experimental data, as well as for simulation of experiments with various inflammatory challenges and associated variations (gene knockouts, inhibition of specific cytokines, etc.). Using this software, the C57Bl/6-specific model was recalibrated for inflammatory analyte data in CD14-/- mice and was used to elucidate altered features of inflammation in these animals. In other experiments, rats were subjected to surgical trauma +/- LPS or to bacterial infection via fibrin clots impregnated with various inocula of Escherichia coli. Mathematical modeling may provide insights into the complex dynamics of acute inflammation in a manner that can be tested in vivo using many fewer animals than has been possible previously.

Animals↗
PubMed2001

[The status of port-site recurrence].

Since laparoscopic surgery has been applied to cancer, an increased number of secondary tumors implanted in the abdominal wall have been reported. Quality of surgery is paramount in the incidence of port-site recurrences. In large prospective series of laparoscopic colorectal surgery, their incidence (around 0.85%) was similar to that reported in open surgery (0.6 to 1.6%) while it is higher for unapparent gallbladder cancer (around 15%) due to direct wound contamination. Viable tumor cells are seeded by inadequate surgical technique or released by advanced tumors. Tumor cells are carried across the abdominal cavity by peritoneal fluid currents and surgical instruments, not by CO2 pneumoperitoneum. CO2 modifies the morphology of mesothelial cells and inhibits peritoneal macrophages. Differences in retroperitoneal/subserosal/intraluminal tumor xenograft models show that CO2 laparoscopy reduces tumor growth when compared to gasless laparoscopy and laparotomy. The local effects of pneumoperitoneum in the wound might be counteracted by using inert gases such as helium, drug-loaded CO2 or various antiadhesive or cytotoxic agents. In clinical practice, port-site recurrences can be effectively prevented by careful surgical technique and prophylactic wound irrigation.

Abdominal Neoplasms↗
PubMedDate not supplied

[Video-assisted thoracic surgery. Current techniques and indications].

Up til recently, thoracoscopy was essentially performed for diagnostic purposes, allowing biopsies of the pleura or peripheral lesions of the lung tissue. Indications with a therapeutic objective were less frequent, usually in cases of recurrent pneumothorax. The recent development of less aggressive, more surgical instruments has virtually "forced" the surgeon to use the thoracoscope. Video thoracoscopy surgery thus entered the therapeutic armenatum. Small access channels less than a centimeter in diameter are used for videothoracoscopy giving an indirect view on the screed of the thoracic contents. Under these conditions, thoracoscopic procedures are possible to treat pneumothorax and resect small pleural or parenchymatous tumours. Inversely, gross resections (lobectomy, pneumonectomy) are technically more complex and raise the nearly unsolvable problem of removing the surgical specimen. In fact, a mini-thoracotomy has been required in many cases, leading to the development of video-assisted thoracic surgery. This new surgical technique is performed via a small incision and is guided by optic probes connected to the video screen. The surgeon can thus follow the entire operation both directly via the mini-thoracotomy and indirectly on the screen. This new approach is an interesting compromise between conventional thoracic surgery and videothoracoscopy.

Humans↗
PubMed2001

A qualitative study of the perceptions of Hong Kong Chinese women during caesarean section under regional anaesthesia.

AIM: to explore Hong Kong Chinese women's experiences and perceptions of elective caesarean section performed under regional anaesthesia. DESIGN: an exploratory study using a qualitative approach. Data were collected by tape-recorded in-depth interviews two to five days after caesarean section. PARTICIPANTS: a purposive sample of 18 Hong Kong Chinese women having an uncomplicated, elective caesarean section under successful regional anaesthesia. SETTING: a post-caesarean ward of a University affiliated District General Hospital in Hong Kong. KEY FINDINGS: the three categories relating to the overall theme of Consciousness during Surgery were: Interacting with others, Experience of birthing, and Awareness of the environment. IMPLICATIONS FOR PRACTICE: the experiences of women, related to the general theme and categories cited above, affected their feelings of security and fulfillment. On the whole, women were satisfied with the regional anaesthesia, preferring to remain conscious throughout the surgery. They appreciated being able to interact with others and listening to music, but needed information regarding what was happening. Many were distressed by the sight and noise of surgical instruments, the narrowness of the operating table, the operating theatre lamps and the coldness of the theatre. Recommendations for practice are made relating to these issues.

Anesthesia, Conduction↗
PubMed1995

[Some aspects of surgical treatment of postoperative ventral hernia].

The results of surgical treatment of of 392 patients with postoperative ventral hernia are discussed. The algorithm of treatment of patients with large hernias was developed. Special preoperative management by dosed pneumocompression in an antioverload costume makes it possible to avoid menacing complications after the operation, which are caused by increased intraabdominal pressure. Test for tolerance to increase of intraabodominal pressure allowed prognostication of the character of the operative intervention: with or without decrease of the volume of the abdominal cavity (autoplasty or alloplasty, respectively). Prevention of wound complications consisted in control of infection, improvement of operative techniques, and use of modern surgical instruments. The prevention of recurrent hernias should be directed at correct choice of the method of plastics and removal of wound complications.

Adult↗
PubMed2002

Sutureless contact lens ring system during vitrectomy.

PURPOSE: To report a new sutureless ring system to fix corneal contact lens in place during vitrectomy. DESIGN: New surgical instrument. METHODS: The sutureless ring system consists of a stainless steel ring that has two upright tabs 180 degrees apart with a hook on the top and two elastic silicone bands 8 mm in diameter to fix the ring to the eyelid speculum. RESULTS: The contact lens fixed in place with the sutureless ring was stable and allowed intraoperative visualization of the fundus. CONCLUSION: This suture-free contact lens system facilitates visualization of the fundus during vitrectomy allowing shorter surgical time. It also enables us to avoid additional trauma associated with the lens ring fixation procedure.

Contact Lenses↗
PubMed2005

Current state and future development of intracranial neuroendoscopic surgery.

Since the introduction of the modern, smaller endoscopes in the 1960s, neuroendoscopy has become an expanding field of neurosurgery. Neuroendoscopy reflects the tendency of modern neurosurgery to aim towards minimalism; that is, access and visualization through the narrowest practical corridor and maximum effective action at the target point with minimal disruption of normal tissue. Transventricular neuroendoscopy allows the treatment of several pathologies inside the ventricular system, such as obstructive hydrocephalus and intra-/paraventricular tumors or cysts, often avoiding the implantation of extracranial shunts or more invasive craniotomic approaches. Endoscopic endonasal transphenoidal surgery allows the treatment of pathologies of the sellar and parasellar region, with the advantage of a wider vision of the surgical field, less traumatism of the nasal structures, greater facility in the treatment of possible recurrences and reduced complications. However, an endoscope may be used to assist microsurgery in virtually any kind of neurosurgical procedures (endoscope-assisted microsurgery), particularly in aneurysm and tumor surgery. Basic principles of optical imaging and the physics of optic fibers are discussed, focusing on the neuroendoscope. The three main chapters of neuroendoscopy (transventricular, endonasal transphenoidal and endoscope-assisted microsurgery) are reviewed, concerning operative instruments, surgical procedures, main indications and results.

Brain↗
PubMed1993

[Hardware].

For effective management of clinical laboratory in spite of a shortage of medical technologists, we modified conventional analytical instruments on the market, and developed the automatic transport mechanism and the robotic analytical instruments to suit the operational needs of our laboratory. Consequently, we succeeded in designing a system in which the results for 89% of all the tests ordered were reported within 60 minutes after the time when the specimens were received at the laboratory. As a result of this laboratory automation system, medical technologists were spared from their routine work, and their expertise was now diverted to the other duties like examination for microbes in hospital facilities, evaluation for sterilization of surgical instruments, and maintenance of measuring apparatuses in the operating rooms. In addition, the technologists also became involved in preventive health activities for university personnel such as: periodical healthy check, and screening programs for adult diseases, and the like. Some became engaged in the health management programs for radiological department workers. Thus, the introduction of this laboratory automation system, enabled the medical technologists to cooperate in hospital operation activities and to contribute to the prevention of iatrogenic disorders.

Automation↗
PubMed2005

Arthroscopic hip surgery.

Many pathological entities that previously could be accessed only through large, open incisions now can be treated arthroscopically. Furthermore, arthroscopy has allowed certain conditions to be diagnosed that previously were unrecognized. Arthroscopic hip surgery has become an accepted surgical procedure with well-defined indications and expected outcomes, primarily because of recent advances in surgical instrumentation and techniques. Hip arthroscopy is performed as a same-day procedure using a fracture table to apply distraction to the hip joint. Coordination among surgeons and perioperative nursing staff members is essential for achieving consistent results and minimizing complications during this technically demanding procedure.

Adult↗
PubMed2005

Nosocomial infections in colo-rectal surgery of the old patient.

Every surgical act, especially in geriatric age, can be a relevant moment in the onset of nosocomial infections. This has a peculiar aspect in patient who undergo colo-rectal surgery, both in election and especially in emergency, in which the simple opening of intestines always involves a minimal contamination. In order to reduce the incidence of infections, and therefore the septic complications of this surgery, it is necessary to pay attention to the preparation of the surgical equipe, of the operating room, of the surgical instruments and, in election, to the careful preparation of the patient through a careful evaluation of the possible bio-umoral alterations, in order to correct them. The results of our experience allow us to say that the prevention of post-operatory sepsis find its main moment in the careful evaluation and eventual correction of the nutritional status, in the stimulation of the immune system, in the antibiotic prophylaxis both parenteral and topical, and, last but not least, in a correct surgical technique. All this is particularly important for patients affected by colo-rectal neoplastic and inflammatory diseases, for which the intestinal bacteria, more virulent in weak and fragile patients, often represent the source of contamination that can start a sepsis and then assume an important part in determining the final result of surgery.

Aged↗
PubMed2001

Incidence and predictors of surgical-site infections in Vietnam.

OBJECTIVE: To determine the incidence of, and risk factors for, surgical-site infections (SSIs). DESIGN: Prospective observational study of all patients undergoing surgery during a 3-month period. SETTING: Two urban hospitals in Hanoi, Vietnam. PATIENTS: All 697 patients admitted for emergent and elective surgery. METHODS: Data were collected on all patients undergoing surgery during a 3-month period at each hospital. We stratified the data by type of surgery, wound class, and Study on the Efficacy of Nosocomial Infection Control (SENIC) risk index. The analysis was done with the data sets from each hospital separately and with the combined data. The risk factors for SSI were identified using a logistic-regression model. RESULTS: During the period of observation, 10.9% of 697 patients had SSI. The SSI rate was 8.3% for clean wounds, 8.6% for clean-contaminated, 12.2% for contaminated, and 43.9% for dirty wounds. The lowest rate of SSI (2.4%) was found in obstetric-gynecologic procedures and the highest rate (33.3%) in cardiothoracic operations. Using the SENIC risk index, the incidence of SSI in low-risk patients was 5.1%; for medium-risk patients, 13.5%, and high-risk patients, 24.2%. In a logistic-regression model, abdominal surgery (odds ratio [OR], 4.46; P<.01) and wound class IV (OR, 5.67; P<.01) were significant predictors of SSI. All patients were treated with prolonged courses of perioperative antibiotics. Overall infection control practices were poor as a result of deficient facilities, limited surgical instruments, and a lack of proper supplies for wound care and personal hygiene. CONCLUSIONS: There was a higher incidence of SSI in low-risk patients in Vietnam compared with developed countries. Excessive reliance on antimicrobial therapy as a means to limit SSI places patients at higher risk of adverse effects from treatment and also may contribute to worsening problems with antimicrobial resistance. Establishment of an infection control program with guidelines for antimicrobial use should improve the use of prophylactic antibiotics and attention to proper surgical and wound-care techniques. These interventions also should reduce the incidence of SSI and its associated morbidity and costs.

Adolescent↗
PubMed1999

Image-guided surgery: preliminary feasibility studies of frameless stereotactic liver surgery.

BACKGROUND: Liver surgery can be difficult because there are few external landmarks defining hepatic anatomy and because the liver has significant vascularity. Although preoperative tomographic imaging (computed tomography or magnetic resonance imaging) provides essential anatomical information for operative planning, at present it cannot be used actively for precise localization during surgery. Interactive image-guided surgery involves the simultaneous real-time display of intraoperative instrument location on preoperative images (computed or positron-emission tomography or magnetic resonance imaging). Interactive image-guided surgery has been described for tumor localization in the brain (frameless stereotactic surgery) and allows for interactive use of preoperative images during resections or biopsies. HYPOTHESIS: The application of interactive image-guided surgery (IIGS) is feasible for hepatic procedures from a biomedical engineering standpoint. METHODS: We developed an interactive image-guided surgery system for liver surgery and tested a porcine liver model for tracking liver motion during insufflation; liver motion during respiration in open procedures in patients undergoing hepatic resection; and tracking accuracy of general surgical instruments, including a laparoscope and an ultrasound probe. RESULTS: Liver motion due to insufflation can be quantified; average motion was 2.5+/-1.4 mm. Average total liver motion secondary to respiration in patients was 10.8 +/-2.5 mm. Instruments of varying lengths, including a laparoscope, can be tracked to accuracies ranging from 1.4 to 2.1 mm within a 27-m3 (3 X 3 X 3-m) space. CONCLUSION: Interactive image-guided surgery appears to be feasible for open and laparoscopic hepatic procedures and may enhance future operative localization.

Animals↗
PubMed1999

Treatment of the patient with upper airway obstruction caused by cancer of the larynx.

The treatment of a patient with imminent airway obstruction caused by a malignant tumor of the larynx is an uncommon clinical problem. These cases need to be evaluated, diagnosed, and managed with care, skill, speed, and above all, appropriateness of intervention. Three methods are available to control the airway: tracheostomy, emergency laryngectomy, and controlled tracheal intubation with or without tumor debulking. Two groups of patients had their airways managed either by tracheostomy and delayed elective surgery or by emergency laryngectomy. There was no survival advantage between the groups, and no increased risk of stomal recurrence was demonstrated. If time permits, the patient is considered suitable, and adequate anesthetic and surgical instrumentation is available, it is currently recommended that the obstructing laryngeal tumor be debulked by cold-steel or, preferably, CO2 laser and that the emergency situation be stabilized and the definitive treatment of the patient be converted to an elective procedure without the need to create a tracheostomy.

Airway Obstruction↗
PubMed1985

The use of the artificial sphincter in the treatment of urinary incontinence in the female patient.

Data analysis of my experience with the implantation of the artificial sphincter shows an overall success rate of 84 per cent. These results are in 139 females ranging from 5 to 84 years of age. The surgery is difficult primarily because the urethral-vaginal septum is not a surgical plane. Even partial injury to these tissues can lead to failure with erosion of the device into the urethra or vagina. The use of a new surgical instrument, the "cutter clamp" (see Fig. 8) is expected to improve results because of the precision it offers in dissecting around the bladder neck. Infection occurred in 4 of 139 patients, or 3 per cent. In one infected patient, the cuff eroded into the urethra. The infection rate may actually be higher because infection might account for some of the other erosions that occurred. Once erosion occurs, secondary infection can obscure the fact that the device was contaminated at the time of the original implantation. The use of a surgical isolation bubble system may lower both the incidence of infection and erosions in the future. The relief to the totally incontinent female by the artificial sphincter cannot be overestimated. The patients are very grateful, especially because most have undergone multiple treatment methods in an effort to cure their incontinence. The effectiveness of the device, barring infection or erosion, is evident by a success of 91 per cent of such patients being socially continent and 66 per cent being completely dry.

Adolescent↗
PubMed1996

Interactive intraoperative localization during the resection of intraventricular lesions.

Mass lesions located in the ventricular system can be surgically challenging. These tumors are often slow growing and reach considerable size before they are diagnosed. These lesions commonly cause multiple obstructions to the circulation of cerebrospinal fluid with subsequent hydrocephalus. They are deeply located in the brain, surrounded by vital neurological and vascular structures, and often have irregular configurations. All these characteristics may pose real problems during surgery in terms of orientation and a optimal resection. For the surgical approach to such intraventricular lesions we are currently using an infrared-based system implemented at Wayne State University that allows intraoperative real-time localization. Three infrared cameras continuously track the position of multiple light-emitting diodes in relation to a predetermined "rigid body". This system can be used with different surgical instruments, and does not interfere with standard neurosurgical techniques. We present our preliminary experience in 18 patients with intraventricular tumors that were operated on between December 1992 and March 1995. Their lesions were located in the lateral ventricles, third ventricle, and pineal region with extension into the posterior aspect of the third ventricle. The use of the interactive infrared-based localizing unit allowed a total resection in 15 cases and a subtotal resection in 3 cases. We report 3 complications, but only one of them was related to the surgical procedure. The postoperative follow-up period ranged from 2 to 24 months. All patients were followed clinically and with postoperative magnetic resonance imaging scans. This interactive infrared system has proven to be a very useful tool, flexible, safe and reliable, increasing surgical efficiency, without a significant increase in the length of resection.

Adolescent↗
PubMed2001

Third trimester binge ethanol exposure results in fetal hypercapnea and acidemia but not hypoxemia in pregnant sheep.

BACKGROUND: The mechanisms by which maternal ethanol abuse during pregnancy causes neurodevelopmental injury in the fetus are not well understood. The purpose of this study was to use a chronically instrumented fetal sheep model system to determine if a binge pattern of ethanol exposure administered throughout the third trimester reduced fetal arterial partial pressure of oxygen (PaO2); a positive finding would support the hypothesis that fetal hypoxemia may play a role in mediating ethanol-related birth defects. METHODS: Pregnant ewes received saline or 0.75, 1.25, 1.5, or 1.75 g/kg of ethanol intravenously over 1 hr beginning on day 109 of gestation (term = 145 days) for 3 consecutive days per week followed by 4 days without exposure. The fetuses were surgically instrumented on day 113, and experiments were performed on days 118 or 132, the 6th and the 12th ethanol exposure, respectively. RESULTS: Ethanol infusions resulted in peak blood ethanol concentrations of 80.8 +/- 6.5, 182.5 +/- 13.5, 224.4 +/- 13.9, and 260.6 +/- 20.0 mg/dl +/- SEM (maternal) and 70.0 +/- 5.9, 149.7 +/- 9.0, 216.9 +/- 14.0, and 233.3 +/- 19.8 mg/dl +/- SEM (fetal) in response to the 0.75, 1.25, 1.5, and 1.75 g/kg doses, respectively. Maternal and fetal heart rate and maternal blood pressure increased whereas fetal blood pressure decreased in a dose-dependent manner in response to ethanol infusions. Maternal and fetal arterial pH decreased and arterial partial pressures of carbon dioxide increased in response to ethanol infusions. Maternal PaO2 decreased whereas fetal PaO2 did not change in response to ethanol infusions. CONCLUSIONS: A binge ethanol exposure paradigm, three consecutive days per week throughout the third trimester at ethanol doses that created blood ethanol concentrations commonly achieved by human ethanol abusers, resulted in changes in maternal and fetal heart rate, changes in blood pressure, hypercapnea, acidemia, and maternal, but not fetal, hypoxemia. We conclude that in an ovine model system, ethanol doses that create blood ethanol concentrations as high as 260 mg/dl do not result in fetal hypoxemia. Remaining issues to address with this model system are whether neurodevelopmental injuries that are associated with maternal ethanol abuse are mediated by a reduction in fetal cerebral blood flow, fetal hypercapnea, or acidemia.

Abnormalities, Drug-Induced↗