PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Surgery, Computer-Assisted”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,207 records · Page 67Linked to original sources
PubMed1994

[A new methodologic approach for determining right ventricular volumes from transesophageal echocardiography].

In order to develop a concept of right ventricular volume estimation accounting for variance in positioning of the transesophageal transducer, non-linear scale transformations of suitable measurements of areas and perimeters were used in a new modeling-approach. This type of modeling supposes self-similarity of ventricular dimensions, a mathematical concept generalizing the notion of proportionality. In a study using right ventricular casts, we were able to demonstrate the geometry of right ventricles complies with these assumptions. The resulting multivariate power law volume estimators were developed by non-linear data fitting by learning-analyses based upon angiographic reference volumes and two areas derived from non-orthogonal sections using a monoplane transducer in a first series of studies, and two orthogonal areas with corresponding perimeters using a biplane device in a second series. Correction factors for systolic and diastolic volumes were applied. By prospective test-analyses angiographic and TEE-derived volumes were compared to evaluate our volume estimator and good agreement was found. Trend was evaluated by correlation amounts to r = 0.95 (n = 22) in series 1 with monoplane transducer, and r = 0.9 (n = 20) in series 2 with biplane transducer. This approach is of use in monitoring right ventricular function in cases with unsuitable transthoracical windows, e.g., in cardiac surgery postoperatively.

Adult↗
PubMedDate not supplied

[Computer monitoring of hemodynamics during assisted circulation and extracorporeal detoxication in abdominal surgery].

Basic central and regional hemodynamic parameters have been studied using a computer monitoring system in 57 patients with acute abdominal surgical diseases during special extracorporeal procedures. Indications for regional assisted circulation (RAC) as well as regularities in hemodynamic changes during and after procedures have been established. The data of monitoring have shown that RAC and RAC in combination with hemosorption have in most cases a marked favourable effect on abdominal hemodynamics: mesenteric and portal blood flow is increased and consequently total hepatic flow is activated. The flow of portal blood leads to an increase in central venous pressure. Unfavourable tendencies have been established in changes of central hemodynamics during the procedures. They are: calculated intervals of the rates of central venous pressure increment and cardiac output decrement. This made it possible to optimize the use of extracorporeal procedures in patients with such diseases.

Abdomen↗
PubMedDate not supplied

[Documentation and computer-assisted evaluation of basic data in a geriatric clinic].

We analyzed data of our clinic by a computer program for discharge letters developed by us. Structure of patients, types of diseases, and success in rehabilitation were recorded. The average age of our patients was 80 years. The biggest group have been the 80-85 years old ones. Two-thirds have been female. Our department is divided into three sections. Admissions made to the section treating patients with acute diseases were made in two-thirds of the cases from surgeries and in one-third from accidents. The section where patients are rehabilitated received only patients who had been admitted before. Two-thirds of them were suffering from surgical diseases (especially orthopedic/traumatic problems). One-third from medical or neurological diseases--especially stroke. In the section for long-term treatment we transferred patients with chronic diseases, mainly from our own sections for acute care and rehabilitation. Twenty percent came from other departments and other hospitals. Discharge: Fifty-one percent of patients treated in the section for acute care were discharged. More than one-fourth were transferred to the section for long-term treatment. Thirteen percent died. Two-thirds of the rehabilitated patients were discharged home. Sixteen percent were treated long-term; about seven percent died. From our section for long-term treatment one-third of the patients were discharged home. Nineteen percent were discharged to nursing homes or other homes for seniors. Forty-one percent died. Younger patients could more likely be discharged without home nursing care and to a household with other members. More than fifty percent of patients of 80 years and older lived alone and required homecare.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1994

[Orbital volumetry as a planning principle for reconstruction of the orbital wall].

Before reconstruction of the orbital walls and other surgical procedures concerning the orbits leading to a modification of pathologically altered orbital volumes, it is useful to measure these volumes in order to allow preciser correction. Orbital volumetric studies on 22 patients and 6 dry skulls were performed using high resolution computer tomography. 14 patients presented enophthalmos of various origin, 3 patients fibrous dysplasia involving the orbits and 5 patients showed no orbital pathology. In 10 patients with unilateral posttraumatic enophthalmos an increase of the bony orbital volume of 20.1% in the average was found corresponding to an enophthalmos of 3.5 mm in the average. Correlation between the severity of the enophthalmos and the increase in orbital volume was found. Enophthalmos could not be correlated to the intraorbital fat volume, especially no atrophy of orbital fat could be demonstrated in these patients. Normal orbital volume measurements of patients and dry skulls were compared to those found in the literature. Planning of the surgery was therefore facilitated before correction of enophthalmos, reconstruction of bony orbital contour after tumor resection and in patients with fibrous dysplasia. Results suggest that the bony orbital enlargement, followed by a change in soft-tissue shape and position is the usual cause for posttraumatic enophthalmos. Changes in volume of soft-tissues themselves are less significant.

Cephalometry↗
PubMed1993

Clinical performance of a rule-based decision support system for mechanical ventilation of ARDS patients.

We developed a clinical decision support system--ventilation protocols--that managed tidal volume and ventilator rate settings during mechanical ventilation of patients with the Adult Respiratory Distress Syndrome (ARDS). We applied these protocols for a total of 10,903 hours in 40 ARDS patients. The clinical staff suspended the protocols for only 5% of the total application time due to medical procedures, surgeries, transient clinical problems not addressed by the protocols, or because of attending physician request. Of 3,148 instructions generated by the ventilation protocols, the clinical staff followed 2,932 (93%). The staff did not follow some instructions because of patient data errors, computer software and protocol logic errors, inability of the clinical staff to implement protocol instructions because of more pressing duties, and clinical staff objections to specific instructions. Sixty percent of the patients treated by the ventilation protocols survived. Our results demonstrate that the ventilation protocols provided a practical and safe decision support system for the mechanical ventilation of ARDS patients.

Clinical Protocols↗
PubMed1994

[Extraction of orbital foreign bodies using a new kind of image processing system].

We present a new localization system in orbital surgery. The procedure is based on the linkage of two methods. A preoperative thin-layer CT scan is taken and the image data are fed into a high-capacity computer which computes a three-dimensional model of the orbit. Intraoperatively, the volume model of the skull is linked to a mechanical arm for position measurement. Surgical instruments can be mounted to this arm. The computer then projects the position of the instrument into the volume model of the orbit, so that the surgeon can follow the movements of his instruments on the monitor. The surgeon has a means of checking position that comes close to constant intraoperative CT monitoring. Thereby the surgeon is able to localize even small foreign bodies without extensive explorations. We present six patients in whom orbital foreign bodies had to be extracted during the past 5 years. A 44-year-old man had an iron foreign body; the external wound was treated surgically elsewhere. Two patients (25 and 22 years old) had glass foreign bodies; in one of them the splinters were not seen using conventional X-ray. Choosing the exact level with the Hounsfield window, the foreign bodies could be demonstrated on the monitor. In three patients with orbital fractures and compression of the optic nerve, dislocated bone splinters were extracted. The localization of those splinters was easy using the imaging system, but would have been rather difficult by other means.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Arcuate keratotomy for the correction of spherical hyperopia in human cadaver eyes.

BACKGROUND: A new experimental surgical technique to correct spherical hyperopia by steepening of the central corneal curvature was performed on human cadaver eyes. METHODS: Ten eyes were used in the study. All were pretreated with glycerin to ensure a uniform corneal thickness between .55 and .65 mm on ultrasonic pachometry. A constant intraocular pressure of approximately 30 to 40 mm Hg was maintained in each eye by the injection of saline into the vitreous cavity. This was verified by pneumotonometry. A vertical blade diamond knife was set at 100% of the thinnest of four paracentral readings. Each eye underwent preoperative computed topography. One set of five eyes had 12 incisions made following a 5.75-millimeter diameter Mendez hexagonal marker that included unconnected T incisions at each junction (ie, "Hex T" pattern). The other set of five eyes had four arcuate incisions made following a 6-millimeter diameter zone marker; each incision was 60 degrees in arc. Immediately after surgery, computed topography was repeated. RESULTS: The hexagonal keratotomy set of eyes had an average steepening of the cornea of 0.80 D with a range of -1.05 to + 4.38 D. The arcuate keratotomy set had an average steepening of +2.12 D with a range of +1.27 to +3.27 D. CONCLUSIONS: This study suggests arcuate keratotomy may be a more effective procedure in the correction of spherical hyperopia when compared with hexagonal keratotomy. The amount of corneal steepening achieved in a cadaver eye model may not be the same as when performed in vivo.

Cornea↗
PubMedDate not supplied

[The brain in stereotaxic coordinates (a textbook for colleges)].

The present textbook is directed forward students of universities and medical colleges, young scientists and practicing doctors dealing with stereotaxic method. The Paxinos and Watson stereotaxic rat brain atlas (1982) is the basis of the textbook. The atlas has been transformed into computer educational program and seven laboratory works: insertion of the electrode into brain, microelectrophoresis, microinjection of drugs into brain, electrolytic destruction in the brain structures, local brain superfusion. The laboratory works are compiled so that they allow not only to study practical use of the stereotaxic method but to model simple problems involving stereotaxic surgery in the deep structures of brain. The textbook is intended for carrying by IBM PC/AT computers. The volume of the textbook is 1.7 Mbytes.

Animals↗
PubMed1993

[Surgical treatment of ventricular tachycardia].

Refractory ventricular tachycardia, resistant to antiarrhythmic drug therapy either because of inefficacy unwanted secondary effects or failure to comply with treatment, is not rare in the chronic phase of myocardial infarction. These considerations reinforce the value of curative therapeutic options, especially those related to antiarrhythmic surgery in these patients. Surgery is usually reserved for those with a ventricular aneurysm where the exclusion of arrhythmogenic zones may be performed with the scalpel, a cryoprobe, laser ... Procedures guided by peroperative endo end epicardial mapping, if possible simultaneous with computerised assistance, are more effective than procedures relying only on visual guiding. The clinical success rate is about 90% and the operative mortality tends to decrease (5 to 6%) with successive improvements to surgical technique. These satisfactory results show the reliability of this therapeutic approach applied to patients exposed to malignant arrhythmias.

Cryosurgery↗
PubMed1993

[Ambulatory continuous recording of pH and pressure in the esophagus].

Ambulatory simultaneous recording of oesophageal pressures and pH is a recently developed technique for evaluation of oesophageal function. The paper describes the experience gained with this technique at the Oesophagus Laboratory, department of Thoracic and Cardiovascular Surgery T, Odense University Hospital. A combined pH and pressure probe is positioned in the oesophagus and connected to a portable recorder. Data are digitised on-line and stored for later transfer to a computer. Analysis of pH-variations and contractile activity is performed automatically. Sections with normal and abnormal acid clearing are shown. A normal pressure response to reflux consists of frequent contractions of normal amplitude and propagation resulting in a stepwise clearing of acid from the oesophagus. Repetitive simultaneous contractions and periods of failed peristalsis are illustrated in sections from a patient with oesophagitis. Contractions of high amplitude and prolonged duration, as well as frequent non-propagating contractions in the distal oesophagus, are elements of a normal peristaltic pattern. The conventional manometric investigation performed under laboratory conditions still has first priority when esophageal dysmotility is suspected. In several instances, however, ambulatory recording of motility and pH may add valuable additional information.

Adult↗
PubMed1993

Selection of patients for surgery.

Patient selection for lumbar laminectomy has been reviewed. The clinical decision for laminectomy depends on the mainstays of history, physical examination, and radiologic examination. A computer model to assist in this difficult task has been presented; the model is yet to be clinically tested. Psychological and psychosocial criteria play an important role in the decision-making process in these patients.

Computer Simulation↗
PubMed1993

[Simulated surgery on a 3D model. Technic and applications].

Treatment planning for the correction of dentofacial deformities includes prediction tracing and model surgery. However, these conventional methods provide only limited information concerning the planned spatial displacement of skeletal structures. In cases of severe deformities we add simulated 3D model surgery in an individually processed life size polyurethane skull to our work-up. The basic steps of the 3D model surgery are described, the advantages outlined and the method discussed.

Computer-Aided Design↗
PubMed1993

[3D endoscopy].

With the aid of a 6 mm 0 degree stereo-endoscope supplied with a 100 Hz monitor and high-speed liquid crystal shutter, three-dimensional endoscopy of the upper airway was realized for the first time. The equipment used is based on alternating sequential projections of left and right eye images on a single tv screen. Two high-speed liquid crystal stereo switches (LCSS) are integrated in glasses and a rapid switching time of 100 microseconds is used. In a comparative study this innovative endoscopic technique was tested for its practicability in sinus surgery and endoscopy of the upper airway. With this equipment an excellent view was obtained of the pharynx, larynx and trachea. For sinus surgery, however, a stereoendoscope with smaller dimensions has to be developed.

Computer Graphics↗
PubMedDate not supplied

Isomorphic corneal topography: a clinical approach to 3-D representation of the corneal surface.

BACKGROUND: Newer methods of refractive surgery produce their effect by reshaping the corneal surface. It follows that topographic representations, used primarily to map refractive power, should now emphasize morphology and contour features. METHODS: We introduce a procedure using commercially available instrumentation which provides isomorphic three-dimensional corneal topography. The representations may be displayed either as refractive power, as is conventionally done, or as the more surgically relevant contour configuration. These images contain data points that are continuous rather than stepped as in the familiar color-coded displays. RESULTS: The technique proved easy to execute requiring no special software or mainframe computing. The corneal displays generated were freely rotatable and rescalable. CONCLUSIONS: In addition to producing clear and intuitive three-dimensional representations, the digital graphics environment allows manipulation unavailable in the conventional color-coded format; such representations should be particularly valuable for pre- and postoperative evaluation.

Computer Simulation↗
PubMed1995

Medicine in virtual environments.

Virtual Environments allow a human to interact with a (computer) system in such a way that a high level of presence in a computer-synthesised world is experienced. In principle, all human senses are involved with the interaction. Many applications may benefit from this type of human-machine interfacing, however, few have emerged so far for medicine. In this paper we elaborate on some realistic potential applications of Virtual Environment technology in the field of medicine. These applications can be found in education/training, therapy, surgery, rehabilitation, diagnosis, telemedicine and biomechanics. The value to be added to these applications by VE technology lies in the fact that patient data or patient models may be moderated to the physician in a more intuitive and natural manner. Despite these potentials, the short-term feasibility of these applications can be put into question for various reasons. Firstly, the current generation of display devices have a resolution that may show to be too low to achieve a sufficiently high degree of realism for medical applications. Secondly, there are no commercially-available actuators for tactile and force feedback which the physician desperately need for the simulation of the contact with the (virtual) patient. Thirdly, the enormous computing power required for these applications (still) needs a considerable investment. With these limitations in mind, we believe that we are at the cradle of a whole new generation of VE applications in medicine.

Computer Simulation↗
PubMed1995

[Indications and use of stereolithographic skull reconstructions in oromaxillofacial surgery].

Stereolithography (SLA), a rapid prototyping technique, was introduced in 1991 at the Clinic for Maxillofacial Surgery in Vienna and was adapted, in cooperation with the company Laserform, for our clinical requirements. As a refinement to physical models milled out of polyurethane, which had been used since 1989, this technique offered new applications for preoperative planning in craniomaxillofacial surgery. The proportions of these 3D models correspond 1:1 to the patients dimensions, with a possible accuracy of 0.25 mm. Since 1992 stereolithography has been used in 124 cases, primarily in traumatology, tumor surgery and in craniofacial surgery.

Adult↗