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[The SITAR Project. A new approach to diagnosis and surgical indication in arteriopathic patients].

The extreme variations with which atherosclerotic disease presents as regards progression index, arterial bed localization frequency, malignity and invasiveness in different ages and often as regards different anatomopathological aspects characterizing the formation and course of the primary lesion, mean that there are still many unknowns in the aetiopathogenesis, diagnosis and operative indications for this disease. Such problems are more and more important to the vascular surgeon who, with the development of atherosclerotic disease, sees the long-term results of his arterial reconstructive surgery compromised. The vascular surgeon is therefore directly involved with his colleagues in the internal medicine and pharmacological departments in problems connected with the pathogenesis of arteriosclerosis, and indeed he contributes to setting new constraints on the choice of prosthetic materials, for use in cases of bridge-work, and in the creation of new surfaces by means of thrombendarteriectomy. On the basis of such considerations, the IInd Surgical Clinic of Milan University began, in 1975, a study whose end purpose was the drafting of a clinical card designed for data computerization. Compiled by the surgeon, it is intended essentially for vascular surgeons. However, as it is personally considered that by the very nature of the disease, the atherosclerosis approach must be interdisciplinary, it also concerns physicians in the internal medicine, pharmacological and dietological departments.

Arterial Occlusive Diseases

Atrial electrogram monitoring in a cardiac care unit.

Routine monitoring of a bipolar atrial electrogram (AEG) simultaneously with the electrocardiogram is a useful and safe clinical technique for the diagnosis of complex cardiac dysrhythmias. The large-amplitude A waves of the AEG can be more reliably identified than the corresponding low-amplitude p waves of the electrocardiogram. Epicardial wires placed during cardiac surgery, catheter-mounted endocardial electrodes, and esophageal electrodes can all be used for routine AEG monitoring. A multipurpose pulmonary arterial catheter with a pair of electrodes, and esophageal electrodes can all be used for routine AEG monitoring. A multipurpose pulmonary arterial catheter with a pair of electrodes mounted on the proximal shaft can be used for combined AEG and hemodynamic monitoring. The equipment needed for AEG monitoring and recording consists of an additional bedside amplifier with 12- to 100-Hz band-pass filter, a dual-channel display scope, and a dual-channel strip chart recorder. Care must be used to keep the atrial electrodes electrically isolated for patient safety. In addition to enhancing the diagnosis and management of dysrhythmias, recording an AEG provides a signal that is suitable for automatic processing.

Arrhythmias, Cardiac

[Operation of acute dissecting aortic aneurysm in the 25th week of pregnancy using hypothermic extracorporeal circulation].

We report on a 24 + 2 weeks pregnant woman with Marfan's syndrome, who acutely developed a dissecting aortic aneurysm with aortic valve insufficiency. Emergency surgery was performed by using hypothermic extracorporeal circulation, whilst the aortic valve and ascending aorta were replaced by a synthetic graft. Foetal heart rates, continuously monitored by using Doppler ultrasound, were shown to be closely correlated with perfusion pressures. By applying perfusion pressures of 90-100 mmHg, we were able to maintain foetal heart rates of approximately 100/min. During the first postoperative day, the CTG was normal for gestational age and no contractions were noted. During the second postoperative night, the patient prematurely delivered a dead 820 g infant (Apgar score 0/0/0/0). In view of this case report, opportunities and problems associated with an application of extracorporeal circulation during pregnancy are discussed.

Adult

Observations on the epicardial activation of the normal human heart.

Serial hand mapping techniques in man have identified 3 to 5 sites of epicardial breaktrough (EBT). However, transmural epicardial excitation from the widely distributed His/Purkinje system suggests a more complicated pattern may exist. Multielectrode arrays used with large mapping systems during surgery often present complicated and sometimes inconsistent activation patterns. The purpose of this work is to reconcile epicardial activation in the normal human heart with anatomical and endocardial/intramural physiological recordings using multichannel computer mapping requiring only a single beat, and rigorously defined and applied activation time detection algorithms. Eighteen subjects undergoing surgery for Wolff-Parkinson-White syndrome were recorded with a 119 site sock array during nonpreexcited sinus rhythm. None had evidence of coronary artery disease and all exhibited a normal 12-lead ECG except during periods of preexcitation or tachycardia. Each was recorded bipolarly and four also were recorded monopolarly. Recordings revealed 8.0 +/- 1.6 EBTs (range 5 to 12). Closely spaced, multiple EBTs often were observed and usually confirmed using different activation time detection algorithms. The earliest EBT always occurred over the anterior right ventricle at 14.3 +/- 6.5 msec (range -1 to 29 msec) after QRS onset. Subsequent EBTs could occur at any ventricular site with variable latencies. In contrast to previous reports describing epicardial spread of activation from a few foci, a mosaic of epicardial activation emerges. These data are consistent with endocardially initiated transmural activation of the epicardium suggested by the anatomy of the His/Purkinje system and intramural recordings.

Algorithms

Prediction of recurrence in giant cell bone tumors by DNA cytometry.

The most interesting therapeutic aspect of giant cell bone tumors is which patients can be cured without a risk of recurrence by intralesional surgery (curettage). To find out the suitability of some DNA cytometric and morphometric parameters for showing differences between this group of patients (n = 9) and those with recurrence (n = 12), the parameters mean ploidy, 2cDI (mean square deviation of the tumor cell DNA content from the normal 2c value), mean nuclear area and its variability were calculated from cytologic specimens prepared by a cell separation technique from formalin-fixed, paraffin-embedded tissues, measuring the values of 100 stromal cells per case by a TV image analysis system. Further measurements were performed on 19 cases of different diseases of the bone and on an additional 17 cases of giant cell tumors without follow-up. The 2cDI allowed us to distinguish the two groups of patients, with and without recurrence, without overlap; even the lowest value for patients with recurrence was higher than the highest value for cured ones. Mean ploidy analysis resulted in a less convincing discrimination of the patients. Mean nuclear area and its variability failed to predict recurrence. Single-cell DNA cytometry provided a parameter, 2cDI, that was able to predict recurrence in patients with giant cell bone tumors with high sensitivity.

Adult

Directional atherectomy for treatment of restenosis within coronary stents: clinical, angiographic and histologic results.

OBJECTIVES: The safety and long-term results of directional coronary atherectomy in stented coronary arteries were determined. In addition, tissue studies were performed to characterize the development of restenosis. METHODS: Directional coronary atherectomy was performed in restenosed stents in nine patients (10 procedures) 82 to 1,179 days after stenting. The tissue was assessed for histologic features of restenosis, smooth muscle cell phenotype, markers of cell proliferation and cell density. A control (no stenting) group consisted of 13 patients treated with directional coronary atherectomy for restenosis 14 to 597 days after coronary angioplasty, directional coronary atherectomy or laser intervention. RESULTS: Directional coronary atherectomy procedures within the stent were technically successful with results similar to those of the initial stenting procedure (2.31 +/- 0.38 vs. 2.44 +/- 0.35 mm). Of five patients with angiographic follow-up, three had restenosis requiring reintervention (surgery in two and repeat atherectomy followed by laser angioplasty in one). Intimal hyperplasia was identified in 80% of specimens after stenting and in 77% after coronary angioplasty or atherectomy. In three patients with stenting, 70% to 76% of the intimal cells showed morphologic features of a contractile phenotype by electron microscopy 47 to 185 days after coronary intervention. Evidence of ongoing proliferation (proliferating cell nuclear antigen antibody studies) was absent in all specimens studied. Although wide individual variability was present in the maximal cell density of the intimal hyperplasia, there was a trend toward a reduction in cell density over time. CONCLUSIONS: Although atherectomy is feasible for the treatment of restenosis in stented coronary arteries and initial results are excellent, recurrence of restenosis is common. Intimal hyperplasia is a nonspecific response to injury regardless of the device used and accounts for about 80% of cases of restenosis. Smooth muscle cell proliferation and phenotypic modulation toward a contractile phenotype are early events and largely completed by the time of clinical presentation of restenosis. Restenotic lesions may be predominantly cellular, matrix or a combination at a particular time after a coronary procedure.

Actins

Proposal of a computerized algorithm for continuous wave CO2 laser on-line control during orthopaedic surgery. Phase I: theoretical introduction and first in vitro trials.

New data obtained from treating polymethylmethacrylate (PMMA) with a non-moving cw- 10 watt-CO2 laser-beam focused at 2.5'', 5'', 7.5'' and 15.75'' are presented. . The final equations R(tc) and Z(tc) for each focal length are proposed. A very interesting correlation between the focal lengths in use and the integrated values of R and Z between 0 and 2 sec has been identified and discussed. This result has been used as basis to define a convenient operative protocol to follow during the planning phase of critical osteotomies or bone cement removal operations using a continuous-wave CO2 laser-beam set to any output power and focused by a set of most common, moving or non-moving focal lengths placed on the operating area. With a simple equation, it is possible to compare craters obtained with moving and non-moving laser-beams at different operative conditions between 0 and 2 sec, time interval which covers the majority of cases. A value of 2.3 +/- 0.1 between ablated volumes of PMMA and bone tissue has been identified. Several case studies regarding orthopaedic procedures from Literature are here reported and compared to the present LCA model. The computerized on-line flow of information for the laser-beam optimization and safety control is also described. Finally, a method for the simultaneous data collection from several operating rooms via a Local Area Network (LAN-Industry Standard IEEE) onto a central data base for later consultation is proposed in its general design.

Algorithms

Computer-aided diagnosis of "dyspepsia".

Experience with computer-aided diagnosis of "dyspepsia" in a consecutive prospective series of 212 patients coming to surgery is described. Analysis is concentrated upon 122 patients who presented to an outpatient clinic de novo for diagnosis. During their first (outpatient) hospital contact, a firm diagnosis was made in just over half of these patients (though where made, it was usually correct). After full investigation, the diagnostic accuracy (prior to operation) was 92.6%. Using data elicited solely from the house surgeon's interview at the time of admission, the computer's overall diagnostic accuracy was 87.7%. The cost of each new computer diagnosis was around 25 new pence ($0.60). and the time taken was about 5 minutes. In a further small series designed to discriminate between organic and functional dyspepsia, the computer correctly assigned all but 1 of 23 patients with organic disease to the correct disease category. However, almost half of 33 patients with x-ray negative dyspepsia were predicted by the computer to have organic lesions. Time alone will tell whether the computer is a better early predictor of eventual organic disease than currently available radiologic methods.

Bayes Theorem

[Visualized three-dimensional reconstruction and image analysis in orthopedics and trauma surgery].

Computer tomography is a commonly used technique for detecting pathological alterations in soft tissue and the skeleton. The remote access to image informations as well as the allocation of display and processing tools via networks enables improved diagnostic and therapeutic practice in orthopaedic and traumatologic surgery. The realization of a user friendly image analysis system displays and processes the acquired images in a modality oriented manner. Our method is based on a unique file format and specific evaluation procedures to produce the input data for three-dimensional display and algorithms for the individual design of implants. Our image analysis system can process the data of conventional computer tomographies with three or more mm distance. In contrast to the available systems there is a low significance of radiation effects.

Computer Graphics

Long term follow-up of EEG changes following therapeutic surgery in epilepsy.

Four cases, given in some detail, illustrate the effort to compare scalp EEGs taken before surgery for intractable seizures with those recorded some years postoperatively, and to relate these, together with the computer analyses of seizure activity recorded in depth, with the pathology found in the removed tissue and, importantly, with the postoperative clinical state of the patient. These four cases illustrate the following results: (1) Confirmation by histology and ultrastructure studies of abnormal neuronal tissue at the site pinpointed by computer analysis of EEGs as the driving focus for the electrical seizure discharge. (2) Correlation of clinical and behavioral improvement with normalization of the EEG, objectively quantified by computer analysis. Examples are given of excellent recovery (3 cases) and one of, at present, partial recovery.

Adolescent

A symptomatic discriminant to identify recurrent ulcer in patients with dysperpsia after gastric surgery.

A questionnaire has been completed by 99 patients referred for investigation of symptoms after gastric operations. The replies were analysed in an attempt to distinguish patients with a recurrent peptic ulcer from those with no recurrent ulcer. All cases were investigated by barium meal, endoscopy, and oral cholecystography. All recurrent ulcers were confirmed by reoperation and patients with gastric carcinoma, gallstones, or symptomatic hiatus hernia were excluded. The study was retrospective in 40 patients in whom the diagnosis was already confirmed when the questionnaire was analysed and prospective in 59 in whom the diagnosis was originally unknown. The replies were analysed with (a) a small computer using Bayes' theorem, (b) weighted tables, and (c) a discriminant analysis. The computer prediction of the prospective data was 85% accurate. The results of simpler methods were almost as good as the computer prediction, and questions related only to the severity of pain and vomiting accurately distinguished recurrent ulcer from other causes of dyspepsia in 81% of patients.

Diagnosis, Computer-Assisted

Evaluation of a collagen/hydroxylapatite implant for orbital reconstructive surgery.

A variety of autogenous and alloplastic materials have been used to correct enophthalmos. Hydroxylapatite (HA), is a calcium-phosphate-based compound that has been extensively studied as a bone replacement material. We studied the properties of a new dense particulate form of HA in a collagen matrix (PFC/HA) implanted in the subperiosteal space of ten rabbit orbits for a period of 6 months. All animals were studied with pre- and postoperative computed tomography (CT) scans, and measurements of induced proptosis and implant volume were made. The proptosis induced by the implant averaged 2.2 mm and was stable over a 6-month period. Implant volume was constant throughout the study. Three-dimensional computer-generated images of the soft tissue, skeletal, and implant surfaces confirmed the implant stability. All animals were studied histologically with fluorochrome bone markers, which revealed minimal foreign body reaction to the implant, no evidence of infection, and marked fibrovascular ingrowth. We found the PFC/HA to possess properties that make it an ideal implant material: ease of availability, ease of handling, no resorption, minimal immunogenicity, infection resistance, no observed migration, biointegration, and no risk of disease transmission. PFC/HA may make an excellent implant material to manage orbital volume.

Animals

Atraumatic evaluation of myocardial revascularization procedures with 43K1.

Least-squares regression analysis was computerized to provide functional color images of myocardial perfusion patterns. In 8 of the 9 patients studied, changes in pattern indicated that the revascularization procedure speeded the appearance time and/or net rate of 43K uptake. The functional images correlated well with coronary arteriograms made before and after surgery. This noninvasive isotope technique may prove to be clinically useful in (a) evaluating coronary artery disease, (b) defining the remaining viable myocardium when an aneurysm is present, and (c) determining the effectiveness of the revascularization procedure.

Adult

Knowledge-based multi-modality three-dimensional image analysis of the brain.

With the recent advances in medical imaging, three-dimensional anatomical and metabolic images of the brain are now available through MR/CT and PET/SPECT imaging modalities. Computerized multi-modality three-dimensional brain image registration and analysis can provide important correlated information for improving diagnosis and studying the pathology of disease. Such analysis may also provide help in planning brain surgery. Further, an anatomical model based quantification and analysis of internal structure can be used to develop a computerized anatomical atlas. Conventional anatomical atlases provide rigid spatial distribution of internal structures extracted from a single subject. The proposed computerized anatomical atlas provides probabilistic spatial distributions which can be easily updated to incorporate the variability of brain structures of subjects selected from pre-defined groups. This paper first presents a review of the current trends in knowledge-based segmentation, labeling, and analysis of MR brain images and then describes the Principal Axes Transformation based registration of three-dimensional MR brain images to develop composite models of selected internal brain structures. The composite models can be used as a computerized anatomical atlas in model-based segmentation and labeling of MR brain images. Three-dimensional labeled MR images of the brain can also be registered and correlated with PET images for analyzing the metabolic activity in the anatomically selected volume of interest. On the other hand, a volume of interest can be selected using the metabolic information and then analyzed for correlated anatomical information using the registered MR-PET images.

Algorithms

[Three-dimensional computerized tomography in trauma surgery. A case presentation].

Three-dimensional images of bone structures can easily be reconstructed from computed tomography data. The technique and the advantages of contemplating reconstructions of bone defects in different directions are described. A special software programme allows to combine all data which are given by the standard CT. The slice diameter is two millimetres. The reconstruction shows bone surfaces in all required views. In traumatic and orthopaedic surgery 3-D-CT is useful in the analysis, detection and preoperative planning of comminuted bone injuries of the spine, pelvis, knee, shoulder and the calcaneus. With this technique it is possible to see the bone in its topographic constellation, to observe fractures in unusual directions and to identify fragments from each other. The surgeon gets a lot of additional information which is helpful to decide on the incision, the reduction and the fixation of fragments. Undesirable effects during operation are reduced, which leads to a more accurate treatment and subsequent better results.

Accidents

Expert computer program for the management of laser surgery.

Since 1960 when the first laser was produced, different types of lasers were developed and over one hundred of them are actually used in medicine. These facts makes very difficult for a surgeon to optimally utilize different types of laser in varying surgical circumstances, unless a laser expert is actually participating in the procedure. As this presence is impractical, if not impossible in every case, we are offering a computer program which presents information in a flexible and friendly way; it is self perfecting and greatly expandable.

Humans

Computer assisted instruction for preoperative and postoperative patient education in joint replacement surgery.

This article describes a comprehensive system for preoperative and postoperative patient education. The system offers a cost-effective method of instruction which encourages patient interaction and practice with decision making. The system was designed for patients undergoing total joint replacement surgery and includes two preoperative lessons, and a third lesson presented postoperatively at the bedside. The computer lessons were developed using data collected by a patient assessment instrument, and collaboratively with input from a nurse clinical specialist, orthopedic surgeon, physical therapist, and computer programmer. In this project, several advantages for using computer assisted instruction for preoperative and postoperative patient education were identified.

Computer-Assisted Instruction

Enlarged acid-base and blood gas calculations by electronical data computing in the blood gas laboratory.

A rapid anaysis of parameters of the acid-base equilibrium and blood gases during open heart surgery and emergency therapy is absolutely necessary. Computing of the several parameters of the acid-base status by slide rules or nomograms is time consuming and can be shortened by computer applications. The central blood gas laboratory consists of a blood gas analyzer for PO2, PCO2 and pH, an electronic desktop calculator, a four color X-Y-plotter and two data lines to the cardiac surgery unit and to the intensive care unit. The time needed for computing and feedback of the parameters could be decreased to one quarter. In addition to numerical data printout, a graphical representation of the several parameters is possible on a X-Y-plotter and includes the Rahn-Fenn-O2-CO2-Diagram with venous admixture, ventilation perfusion ratio, alveolar dead space ventilation and the standard and actual oxygen dissociation curve as well as the pH/HCO3- Acid-Base nomogram. Furthermore, a computer diagnosis of the actual disturbances can be plotted.

Acid-Base Equilibrium