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Results for “Surgery, Computer-Assisted”

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PubMed1976

An analysis of potential physiological predictors of respiratory adequacy following cardiac surgery.

More than 50 potential physiological and clinical predictors of postoperative respiratory adequacy were examined in an attempt to identify those few variables which, singly or in combination, best predicted the outcome of the first trial of spontaneous respiration following cardiac surgery. This trial was initiated when patients seemed hemodynamically stable and relatively alert following surgery. Analysis of data from 124 patients identified the following useful predictors: forced vital capacity, total lung capacity, and maximal mid-expiratory flow rate from preoperative pulmonary function tests; resting cardiac index from preoperative cardiac catheterization; postoperative compliance and resistance measured by a computer-based monitoring system; postoperative vital capacity per kilogram, and maximum inspiratory force, measured at the bedside prior to the weaning trial. Stepwise linear discriminant analysis indicated that vital capacity per kilogram and maximum inspiratory force were the most useful predictors, the dividing line between successes and failures being represented by a vital capacity per kilogram of 15 ml. and a maximum inspiratory force of 28 cm. H2O. Mean values of successes were 18.3 +/- 7 ml. per kilogram and 30.7 +/- 9 cm. H2O and, for failures, 11.9 +/- 4 ml. per kilogram and 24.3 +/- 8.4 cm H2O. These physiological variables assess patient effort acting upon an abnormal pulmonary system. Measurements of passive pulmonary mechanics, cardiac function, and the measurement of arterial blood gases were suprisingly poor predictors.

Airway Resistance↗

PubMed1995

[Anatomical analysis of small bronchial arteries in front of the trachea by 3D-CT and digital subtraction angiography: implications for esophageal cancer surgery].

To preserve blood supply to the trachea and bronchus in the surgical procedure for esophageal cancer, anatomical characteristics of small bronchial arteries which course in front of the trachea were analysed by three-dimensional computed tomography (3D-CT) and digital subtraction angiography (DSA). In the 3D-CT study using five mediastina, three dimensional images of the bronchial arteries were reconstructed after the injection of contrast medium into the intercostobronchial arteries. Thus the detailed vascular network of the course of the small bronchial arteries in front of the trachea could be delineated. In the DSA study using seven mediastina, through this network of bronchial arteries, the branches originating from the aorta and the arteries supplying the cranial portion of the trachea could be viewed. These results indicate that the bronchial arteries are connected by a vascular network in front of the trachea. Based on these detailed findings, it is considered critical to avoid damage to the intercostobronchial artery and also the network of bronchial arteries in order to preserve blood supply to the trachea and bronchus.

Angiography, Digital Subtraction↗

PubMed1995

[3-dimensional computerized tomography in diagnosis and surgical planning of intracranial aneurysms].

Established alternative methods of visualisation of intracranial vessels--MR-angiography and angio-CT--give only two dimensional views similar to angiography. It is a subjective matter of the neurosurgeon's imagination to produce three dimensional views on the basis of these methods. Three dimensional processing of dynamic sequence or helical axial computed tomograms give any number you like of stereo-scopic views of the Willisi circulus. Comparing the usefulness of DSA and 3D-CT in 34 aneurysms, the latter often gives supplementary information concerning the direction, neck and adjacent arteries, helpful in planning surgery treatment. It is difficult or sometimes impossible to separate basal aneurysms (a.c.i.) from sinus cavernosus and skull base by this method, but especially in aneurysms located in the area of a.com.a. and c.m.a. the 3D-CT is sufficient for diagnosis and planning surgical treatment without DSA.

Angiography, Digital Subtraction↗

PubMedDate not supplied

[Late results of pathogenetically-oriented surgical treatment in congenital glaucoma and problems of medical rehabilitation].

Results of pathogenetical surgical treatment of congenital glaucoma were analyzed in late periods after surgery, from 1 to 17 years, in 105 patients (171 eyes). Ophthalmic tone normalization was attained in 87.5% of cases. High vision acuity was retained in 57.7% of cases. The principal causes of reduced central vision in process stabilization were astigmatism in 61.7%, amblyopia in 71.5%, strabismus in 59%, anisometropia in 22.8%. To improve vision acuity computer-aided pleoptic treatment was carried out in the postoperative period in 42 children (76 eyes). The efficacy of the method was 84.2%.

Age Factors↗

PubMed1994

[Evaluation of the aorta and supra-aortic vessels with spiral CT and 3-dimensional vascular reconstruction after operation of aortic isthmus stenosis].

Aneurysm formation, restenosis, and hypertension are well known complications after surgery for coarctation of the aorta (CoA). In order to assess long-term results, 46 patients were studied by spiral computed tomography and three-dimensional reconstruction after an interval ranging from 1 to 21 years (median 10 years) after surgery for coarctation. Spiral computed tomography showed pathological changes of the aorta in the majority of patients. Typical findings were ectasy or aneurysm formation of the ascending aorta, hypoplastic aortic arch, ectasy or aneurysm formation of the supraaortic vessels, circumscript aneurysm of the descending aorta at the side of surgery, restenosis of the descending aorta and malformations and anomalies of arterial vessels. In order to initiate adequate treatment of such specific complications as restenosis, aneurysm and/or arterial hypertension, regular controls are necessary in patients after surgery for aortic coarctation. In addition to clinical examination and besides magnetic resonance imaging and angiography, spiral computed tomography is an effective non-invasive imaging method for follow-up.

Adolescent↗

PubMed1994

Image analysis of the distribution of intraperitoneally administered fluids in patients with ovarian cancer.

Patients are selected for intraperitoneal chemotherapy based on the condition of the peritoneal cavity and the volume of residual disease, as determined by second-look surgery. Several techniques have been described to assess the distribution of intraperitoneal fluids. They rely on point, as opposed to area, measurements. We performed serial radionuclide scans of 15 patients undergoing intraperitoneal chemo for ovarian cancer. Scans were performed following intraperitoneal administration of 500-1000 ml of 99Tc-labeled human serum albumin in normal saline. Each patient underwent three scans at least 4 weeks apart. Radionuclide scans were digitized for computerized analysis. Area in picture elements (pixels) and optical density (mass) of the 99Tc-labeled regions were determined and analyzed for similarities in the pattern of distribution. Area analysis was used to divide the patients into two groups. Group 2 patients (n = 7) had more patients with < 0.5 cm of residual disease (P = .051) and no evidence of disease (P = 0.1) compared with group 1 patients (n = 8). No differences in overall survival were found (P = 0.21). No objective measurement of distribution of intraperitoneally administered fluids exists. Computer image analysis may be an improvement over static scoring techniques to assess non-invasive imaging studies.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1994

[Pathogenesis and treatment of accommodative disturbance].

Using a computer-assisted infrared optometer with a pupillograph, we tried to obtain basic understanding of accommodative disturbance and its by investigating tonic (dark focus) level of accommodation and quasi-static accommodative response. In normal volunteers in whom either visual fatigue, general fatigue, or drunkeness was loaded intentionally, myopic shift of refraction, increased refractive fluctuation, and miosis were induced in all cases but the effect on amplitude of accommodative response was minimal. Subjects that worked at a computer terminal all day for 2 years, but not controls, developed myopic change at a statistically significant level. The effect on tonic level of accommodation of subject age, sustained near-vision tasks, and topical application of autonomic-related drugs was investigated. In subjects with severe eyestrain, myopic shift of tonic accommodation and prominent pupillary unrest were observed, suggesting increased parasympathetic excitation. One patient who was accidentally exposed to diisopropyl fluorophosphate, a potent cholinesterase inhibitor, showed a phenomenon similar to that mentioned above. Chaos attractors based upon the Shil'nikov phenomenon were introduced for evaluation of microfluctuation and pupillary unrest, as first applied by Sumida et al. Topical application of low-dose cyclopentolate hydrochloride was effective for treating accommodative abnormality in professional computed workers, who sometimes develop abnormal parasympathetic excitation. Based on quasi-static accommodation measurements, accommodative abnormality after head and neck injury, including whiplash injury, was divided into two completely different states: accommodative spasm and palsy. Since quasi-static accommodation was greatly affected by satellite ganglion block, sympathetic innervation from cervical ganglions may strongly influence accommodative response. Hyperthyroidism, which may be accompanied by sympathetic hyper-excitation, showed diminished accommodative response. In patients after refractive surgery by excimer laser, there was no difference in accommodative response before and after surgery, although tonic accommodation was slightly unstable after surgery. These findings suggest that the evaluation of tonic level or a similar state of accommodation and pupillary unrest will yield extremely valuable information in regard to various accommodative disturbances.

Accommodation, Ocular↗

PubMed1994

[Follow-up of fracture healing--indications and clinical relevance of direct radiographic magnification in comparison with conventional roentgen imaging].

Comparison of 83 magnification radiographs with corresponding conventional X-rays showed that direct radiographic magnification (DIMA) yielded additional information in 39 cases (47%), which had implications for the treatment in 19 cases (22.9%). In 11 cases callus was first visualized in magnification radiography; the earliest evidence of callus was found 14 days after surgery. Since magnification radiography means the region that can be examined is smaller, conventional radiographs were necessary in 32.5% of cases to find the position of the fracture in long bones. For statistical evaluation interobserver analysis was performed, anatomical and pathological structures being graded according to four levels. Magnification radiography proved superior in all structures examined. Magnification radiography can be recommended as an additional method to monitor fracture healing. Computed radiography was used together with magnification radiography to reduce the radiation dose and to perform image processing including simulation of conventional technique and edge enhancement. DIMA is a valuable tool in the evaluation of fracture stability and in the adjustment of distraction rates in limb-lengthening procedures.

Adult↗

PubMed1994

Craniosynostosis: diagnostic imaging with three-dimensional CT presentation.

PURPOSE: To measure diagnostic performance and preference of two three-dimensional CT reconstruction modalities (voxel-gradient and surface-projection) displayed two ways (conventional and unwrapped) in craniosynostosis confirmed by surgical inspection and histologic analysis of resected sutures. METHODS: High-resolution 2-mm contiguous CT sections were obtained and three-dimensional reconstruction images generated for 25 infants and children with skull deformities before surgical treatment of craniosynostosis. Two pediatric radiologists and two neuroradiologists first ranked images by their own preferences for diagnostic use. Then they diagnosed craniosynostosis from images presented in random order and blinded. The standard of reference was inspection during surgery and histologic evaluation of excised sutures. Finally, reviewers repeated their subjective preference tests. RESULTS: The least experienced radiologist had 100% sensitivity for all imaging modalities and specificities ranging from 43% to 83%. The two most experienced radiologists performed nearly identically, with sensitivities of 96% and specificities of 100%. After performing diagnostic tasks using all image types, all radiologists preferred conventional surface projections. CONCLUSION: Experienced readers can achieve nearly perfect diagnostic performance using the latest three-dimensional CT reconstruction images, making it a contribution to the diagnostic process. Although performance is nearly identical for all modalities, readers strongly prefer conventionally presented surface-projection images.

Algorithms↗

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↗