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PubMed1996

[LGM inferior vena cava filters--follow up 50 patients].

In the Department of Medicine at the Institute of Tuberculosis and Lung Diseases 50 LGM inferior vena cava filters have been inserted since 1993. Indications for filters placement were as follows: recurrent pulmonary embolism (PE) despite anticoagulation-16 patients (pts), severe bleeding complications of thrombolytic or anticoagulant therapy-9 pts, contraindications for thrombolytic and/or anticoagulant treatment-3 pts, massive PE-6 pts, chronic thromboembolic-major vessel pulmonary hypertension (CTEPH)-18 pts, extensive deep vein thrombosis of lower limbs or vena cava inferior in patients with urgent indications for surgery-10 pts. In every patient diagnostic procedures were performed after 1, 3, 6, 12, 24 and 36 months of follow-up period. Only one non-fatal episode of recurrent PE was documented. Other complications were rare and insignificant. The LGM inferior vena cava filters are effective and safe in such selectively chosen group of patients.

Female↗
PubMed2001

Mini-trabeculectomy in eyes with high risk of scarring: midterm follow-up.

PURPOSE: To report on the surgical outcome after at least 1 year of follow-up of mini-trabeculectomy (without scleral radial incisions), which took place in eyes at high risk of postoperative filtering bleb scarring. METHODS: In a prospective, institutional study, mini-trabeculectomy was performed on 26 eyes of 26 consecutive patients aged 40 years and older who had undergone a previous intraocular surgery or had had a post-traumatic recessed anterior chamber angle. The surgical procedure, a modification of the standard trabeculectomy, involved a 3-mm fornix-based conjunctival flap, sclerostomy at 1 mm from the limbus, and a sclerocorneal tunnel without radial incisions. During surgery, 0.4 mg per ml of mitomycin C was applied in the scleral pocket of each eye for 3 minutes. Of the 26 eyes, each of two eyes underwent an intraocular intervention during the first postoperative year and therefore was evaluated only for surgical complications. Another eye underwent inferior mini-trabeculectomy, and three other eyes did not complete 12 months of follow-up. Twenty eyes have completed 12 months or more of follow-up and were included in the midterm calculations of intraocular pressure control. RESULTS: Mean preoperative intraocular pressure (n = 20) was 32.2 +/- 9.5 mm Hg with 3.3 +/- 0.9 hypotensive medications. After 12 to 37 months (mean, 22.1 +/- 6.6) of follow-up, intraocular pressure was 20 mm Hg or less in 18 of 20 eyes (90%) and the mean intraocular pressure was 17.4 +/- 2.9 mm Hg (range, 12 to 23) with 1.1 +/- 1.2 hypotensive medications (range, 0 to 4). At that time, the filtering bleb was low and fleshy in appearance in 15 eyes (75%). Postoperative complications of the 22 eyes included early postoperative aqueous leakage in one eye (4.5%); cataract extraction took place in one eye and vitrectomy was performed in another eye, 7 and 3 months postoperatively, respectively. The four eyes that were excluded from the study had controlled intraocular pressure at the last examination. CONCLUSION: Mini-trabeculectomy in eyes with high risk of scarring was found efficacious and relatively safe. The relatively small peritomy, the tunnel approach, and the avoidance of radial incisions seem to offer important advantages over the standard trabeculectomy.

Aged↗
PubMed1997

Computerised prostate boundary estimation of ultrasound images using radial bas-relief method.

A new method is presented for automatic prostate boundary detection in ultrasound images taken transurethrally or transrectally. This is one of the stages in the implementation of a robotic procedure for prostate surgery performed by a robot known as the robot for urology (UROBOT). Unlike most edge detection methods, which detect object edges by means of either a spatial filter (such as Sobel, Laplacian or something of that nature) or a texture descriptor (local signal-to-noise ratio, joint probability density function etc.), this new approach employs a technique called radial bas-relief (RBR) to outline the prostate boundary area automatically. The results show that the RBR method works well in the detection of the prostate boundary in ultrasound images. It can also be useful for boundary detection problems in medical images where the object boundary is hard to detect using traditional edge detection algorithms, such as ultrasound of the uterus and kidney.

Humans↗
PubMed2006

Risk factors for restenosis after carotid artery angioplasty and stenting.

OBJECTIVES: With carotid artery stenting (CAS) becoming an ever-increasing procedure, we sought to determine risk factors for in-stent restenosis after CAS. METHODS: Consecutive patients undergoing CAS between January 2002 and October 2004 at a tertiary care hospital were retrospectively reviewed. Patient, filter, and stent selection were left to the discretion of the attending surgeon. High-risk patients were defined by significant comorbidities or a hostile neck (prior surgery or radiation, or both), and risk factor analysis was performed. In-stent restenosis was defined as >60%, and selective angiography was performed on patients with an in-stent restenosis >80% by duplex ultrasound imaging. RESULTS: Reviewed were 101 patients (55 men, 46 women) who underwent 109 CAS procedures. Comorbidities were typical for patients with atherosclerosis. In addition, 38% (n = 41) of procedures were performed in patients who had prior neck surgery, of which 29% (n = 32) had previous ipsilateral carotid endarterectomy. Seventeen patients (16%) had a history of neck cancer, and all had prior neck radiation. Median follow-up was 5 months (range, 0 to 30 months). Neurologic complications included three transient ischemic attacks (2.8%) and one nondisabling stroke (0.9%). There were two myocardial infarctions (1.9%) and no periprocedural deaths (30 days), for a combined stroke, myocardial infarction, and death rate of 2.9%. Asymptomatic in-stent restenosis developed in 12 carotids (11%), five of which required endovascular intervention, with a mean of 6 months to restenosis. Univariate Cox proportional hazard regression models were used to determine risk factors for the development of restenosis. Prior stroke, transient ischemic attack, amaurosis fugax, and prior neck cancer were all significant risk factors. When these significant risk factors from univariate analysis were put into multivariate analysis, however, the only marginally significant risk factor was prior neck cancer (P = .06). Kaplan-Meier analysis revealed a cumulative freedom from in-stent restenosis at 24 months of 88% +/- 6% in patients without neck cancer compared with 27% +/- 17% (P = .02) in patients with neck cancer. CONCLUSIONS: CAS has been shown to be safe and effective in high-risk patients, with minimal adverse events.

Adult↗
PubMed1991

Millipore analysis of valvular fluid in sterile valve malfunctions.

Malfunctions of sterile shunts may result from valvular dysfunction. The cerebrospinal fluid shunt valves of 14 patients were excised during surgery for sterile shunt malfunctions. In 6 patients, the malfunction was due specifically to a valve malfunction. Cerebrospinal fluid from each valve was passed through a millipore filter, which was then stained using either hematoxylin and eosin or periodic acid-Schiff. The stained millipore filters were examined by a neuropathologist who was unaware of the cause of the shunt malfunction. Although inflammatory cells were detected in all cases, the patients with valve malfunctions were found to have numerous macrophages and giant multinucleated reactive cells within their valves, while cerebrospinal fluid from valves that had been removed during shunt revisions for reasons other than a malfunctioning valve contained only rare mononuclear cells or macrophages. No valve contained erythrocytes, fibrinous matter, neural or glial tissue, or choroid plexus. The possible causes of valve malfunction, including infection and allergic reactions, are discussed. All patients did well after simple replacement of the valve.

Adolescent↗
PubMed2000

Quantification of posterior capsular opacification in digital images after cataract surgery.

PURPOSE: To describe a software program developed to provide an objective assessment of the amount of posterior capsular opacification (PCO) in high-resolution digital images of the posterior capsule after cataract surgery. METHODS: Images are analyzed by a set protocol of defining the area of the posterior capsule, removing the Purkinje light reflexes by intensity segmentation, contrast enhancement, filtering to enhance low-density PCO, and variance analysis using a co-occurrence matrix to assess texture. The accuracy of the system was tested for validity and repeatability. RESULTS: The software developed has been demonstrated to be an objective method of quantifying PCO. In validation tests, the image analysis-derived measure of PCO showed good agreement with clinically derived measures of PCO. Clinicians assessed PCO on a computer screen image and also under slit lamp examination (Pearson correlation coefficient for both methods >0.92). The entire acquisition and analysis system was demonstrated to have a confidence limit for 2 SDs of 9.8% for group data. CONCLUSIONS: This system is capable of producing an accurate and reproducible measure of PCO that is relevant to assessing techniques of PCO prevention.

Aged↗
PubMed1988

[Early changes of oxypurines in rat brain following focal cerebral ischemia].

Cerebral hypoxanthine, xanthine, and uric acid levels were measured by high-performance liquid chromatography (HPLC) for up to 4 hours following focal cerebral ischemia in the rat. Fifty male Sprague-Dawley rats were subjected to occlusion of the left middle cerebral artery under halothane inhalation anesthesia. The animals were sacrificed with microwave at 30, 60, 120, and 240 minutes after surgery. The brains were removed and divided into right and left hemisphere. Each hemisphere was homogenized with perchloric acid and centrifuged. The supernates were filtrated with membrane filter. An aliquot of the filtrate was used for measurement of uric acid, xanthine, and hypoxanthine in both of the ischemic and contralateral hemisphere by a HPLC system. A HPLC with multiple ultraviolet spectroscopy was used for measuring hypoxanthine and xanthine. Identification of hypoxanthine and xanthine was made by parallel chromatography of standards, disappearance with xanthine oxidase, and the spectrum of UV absorption. Uric acid was measured by reversed-phase HPLC with electrochemical detection as reported previously. Hypoxanthine increased rapidly and arrived at a peak value at 60 minutes. Xanthine increased not so rapidly as hypoxanthine and showed the highest value at 120 minutes. Uric acid also increased significantly but very slowly and did not seem to reach the peak value during the observation period. Hypoxanthine is oxidized to xanthine and then xanthine is oxidized to uric acid at the terminal stage of purine degradation. The order of peak times of cerebral hypoxanthine, xanthine, and uric acid levels following cerebral ischemia corresponds to the order in purine metabolism. This result strongly suggests that hypoxanthine is degraded into uric acid in ischemic rat brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Open indications for endovascular surgery].

Endovascular techniques are becoming a part of minimally invasive surgery. The AIM is either preservation or reconstruction of the vascular lumen without the risk involved in conventional reconstructive procedures. The therapeutic success is often only palliative and not durable, because only the local cause of the disease is excluded and not removed definitively. Despite improvement in the technical equipment the indication for endovascular surgical treatment remains questionable and is the subject of experimental vascular research. Like other innovative procedures, the place for endovascular procedures will emerge in relation to the individual patient risk patient concerning age, concomitant diseases and cardiorespiratory conditions. In comparison to conventional reconstructive procedures endovascular techniques are being strongly pushed by specialists and industry because the risks of treatment are believed to be significantly lower. However, the risks of conventional vascular reconstruction are often overestimated and, as a rule, the failure rate in endovascular reconstructive surgery is often underestimated.

Angioplasty, Balloon↗
PubMed1976

Maintenance of aseptic barriers in the conventional operating room: general principles.

Contamination of operative wounds during surgery occurs primarily through contact and secondarily through the airborne route. Inspection and maintenance of air-handling equipment is essential, with special reference to air intakes, filters, humidifiers, and exhaust systems. Doors should remain closed to maintain positive pressure. Surgical attire for all personnel must provide for complete coverage of hair and arms. Intensive interim cleaning of all horizontal sufaces between operations is essential. The infection rate is proportional to the duration of the operation and the number of personnel in the room, and inversely proportional to the air changes per hour.

Air Conditioning↗
PubMed1994

Quantitative and qualitative analysis of polyethylene wear particles in synovial fluid of patients with total knee arthroplasty. A preliminary report.

Synovial fluid from 13 knees undergoing revision total knee arthroplasty was subjected to chemical digestion and ultrafiltration. Scanning electron microscopy was used to visualize high-density polyethylene particles filtered from the fluid, and the images were analyzed using digital imaging software. This data were correlated with polyethylene wear patterns seen at the time of revision surgery. Patients' prostheses with gross polyethylene wear were differentiated from those with surface deformation and burnishing. The knees had been in situ for periods ranging from 3 to 112 months, and included 6 different prosthetic designs. The average area of the polyethylene particles measured ranged from 41 to 701 mu 2, and the total number of particles identified for each sample ranged from 38 to 279 mu 2. The largest particle identified had a surface area of 17,500 mu 2. Using the fluid volume analyzed, the particle area per milliliter of synovial fluid examined was calculated, and values ranged from 6.22 x 10(4) to 2.06 x 10(6) mu 2/ml. Visualization of high-density polyethylene using scanning electron microscopy allows greater resolution of morphologic detail than is possible with routine histologic examination using light microscopy. There were trends toward increasing particle size and total particle area in patients with gross polyethylene wear. The area of high-density polyethylene per milliliter of fluid in patients with gross wear was found to be statistically greater than that of patients without gross wear (p = 0.047). This technique offers a potentially valuable method of evaluating the status of high-density-polyethylene bearing surfaces in situ using a noninvasive technique.

Aged↗
PubMed2004

Deep vein thrombosis and malignancy: a surgical oncologist's perspective.

Oncology patients are at increased risk of developing deep vein thrombosis (DVT) and its potentially fatal sequel, pulmonary embolism. This is due to multiple factors, including the presence of the malignancy itself, comorbid factors and therapy-related interventions. Issues that are peculiar to venous thrombosis in the oncology setting are discussed, based on a MEDLINE search of the English literature. These include the need to screen for malignancy in idiopathic DVT, a high index of suspicion for venous thrombosis in the cancer patient, the use of vena cava filters, and the anti-neoplastic effects of heparin. Asian patients appear to have a lower incidence of DVT compared to Caucasians. A recommended regimen for prophylaxis of DVT must take into account the varying thrombosis risk associated with different malignancies. Cancer patients not undergoing abdominal, pelvic or orthopaedic surgery (e.g. mastectomy) should use elastic compression stockings and be mobilized early, whereas low-molecular-weight heparin should be given to those undergoing more major surgery. In advanced malignancy, treatment of DVT palliates symptoms. These patients may need long-term anticoagulation with warfarin.

Anticoagulants↗
PubMed1987

Effect of decreased perfusion pressure on glomerular permeability in the rat.

In several models of glomerular injury and in studies with tracers that affect systemic or regional hemodynamics, renal perfusion rate and perfusion pressure are often markedly reduced. In order to distinguish the possible effect of these hemodynamic changes from changes in intrinsic properties of the glomerular filter, we investigated alterations in glomerular permeability in anaesthesized rats with acutely lowered perfusion pressure induced by ligation of the aorta to a mean arterial pressure (MAP) of approximately 55 mmHg. Control rats underwent similar surgery except for aorta constriction. Filtration properties were studied by determining the fractional clearance of three differently charged horseradish peroxidases, with a molecular radius of approximately 30 A and an isoelectric point of 4 (anionic), 7.6 (native), or 9 (cationic) (N = 4 per group). Glomerular filtration rate was determined by inulin clearance and renal plasma flow was determined by inulin extraction. In addition, the effect of lowering MAP on penetration of intravenously administered ferritin into the glomerular capillary wall was studied by electron microscopy and morphometric analysis. The results showed that glomerular filtration rate and renal plasma flow decreased proportionally upon lowering MAP. The fractional clearances of the three differently charged peroxidases were unchanged, indicating unaltered charge-selective barrier function of the glomerular filter. In the animals with reduced MAP, no significant differences were found in ferritin concentration in glomerular capillary lumina of superficial glomeruli as compared to control animals. Penetration of ferritin into the capillary wall was found to be proportional with the amount of ferritin in the lumen in both experimental (N = 5) and control animals (N = 4). In conclusion, a decrease in perfusion pressure causing a marked reduction of glomerular filtration rate and renal plasma flow, had no effect on the charge discriminative properties of the glomerular filter and on permeability to large protein molecules such as ferritin. Furthermore, this study shows that in order to assess glomerular permeability by ultrastructural tracer studies, it is necessary to relate the intramembranous and intraluminal concentration of a given tracer.

Animals↗
PubMed1998

[The use of hydrophobic PALL BB22-15MS filters in cross-infection prevention during anesthesia].

OBJECTIVE: Microbiological testing evaluations of hygienic procedure properties using PALL BB22-15MS filters to prevent contamination of "single use" breathing circuits during anesthesia. DESIGN: Prospective study. SETTING: Two operating rooms in a University hospital. PATIENTS: One hundred and thirty eight patients underwent general anesthesia for urologic surgery procedures. Patients with positive tests for HIV, B and C hepatitis and those considered to be at risk for HIV infection were excluded. The study was divided into five phases on the basis of times of usage of the same circuit for an increasing number of patients: in phase I, microbiological tests were performed on 4 circuits used on 4 different patients; in phase II the same tests were performed on 2 circuits each used on two different groups of three patients; in phase III, a circuit was used on a group of 15 patients and another on a group of 16 patients and the results were analysed; in phase IV a circuit used in a group of 32 patients was evaluated and phase V involved the analysis of a circuit that was used in a group of 65 patients. INTERVENTIONS: A filter was left in place between the patient and the circuit's Y-piece during all phases of anesthesia. The level of microbial contamination of breathing circuits was analysed in order to evaluate the reliability of the procedure. RESULTS: All analysed circuits remained uncontaminated. Staphylococcus hominis was revealed in respiratory circuit no. 6 of phase II, probably as a consequence of secondary contamination. CONCLUSIONS: Our results confirm that this procedure with the routine placement of a PALL BB22-15MS filter at the circuit's Y-piece can provide an adequate level of protection against cross-infections during anesthesia. The hygienic protocol proposed may allow the change of the anesthetic breathing only once a month.

Anesthesia, Closed-Circuit↗
PubMed2005

Penetration of topically applied fluorescein into eyes with avascular filtering bleb after trabeculectomy.

PURPOSE: To evaluate intraocular penetration of topical fluorescein in eyes with avascular blebs after trabeculectomy. DESIGN: Case control study. METHODS: The study included 11 eyes with open-angle glaucoma and functioning avascular blebs, six of which were treated with topical anti-glaucomatous medications and had no history of surgery, 15 with open-angle glaucoma, and untreated eyes suspected of having open-angle glaucoma. The fluorescein concentration in the superior peripheral and central corneal stroma and anterior chamber was determined 30 and 60 minutes after fluorescein instillation. RESULTS: The fluorescein concentration in the superior cornea was significantly higher in eyes with blebs or those topically treated than in untreated eyes (P <.01); there was no significant difference in the central cornea. The fluorescein concentration in the anterior chamber was much higher in eyes with blebs than in those that were untreated or topically treated (P <.001). CONCLUSION: The presence of avascular filtering blebs greatly enhances intraocular penetration of topically instilled fluorescein.

Administration, Topical↗
PubMed1991

The effects of subconjunctival mitomycin-C on glaucoma filtration surgery in rabbits.

A prospective, randomized, masked, placebo-controlled study was performed to determine whether a single, intraoperative subconjunctival application of a 0.5-mg/mL solution of mitomycin-C enhances the success of full-thickness filtration surgery in rabbits. Compared with control eyes, mitomycin-C-treated eyes showed significant increases in bleb duration from 8.1 +/- 2.4 to 68.0 +/- 20.8 days and in intraocular pressure reduction from 6.0 +/- 3.0 to 63.6 +/- 21.5 days. Histopathologic evaluation confirmed the inhibitory effects of mitomycin-C on fibrovascular, fibrocellular, and collagenous organization of the filtering blebs that resulted in their preservation. Transient, superficial, corneal vascularization anterior to the bleb occurred in all mitomycin-C-treated eyes. No other clinical or pathologic signs of undesirable side effects were noted. We studied the effectiveness and safety of a single intraoperative application of mitomycin-C in prolonging the success of filtration surgery in rabbits and its potential for similar use in humans.

Administration, Topical↗
PubMed2006

Returning reservoir blood to right atrium during extracorporeal circulation for descending aortic surgery.

We report our techniques on conducting a closed-circuit femoral-femoral bypass during descending aortic surgery by which collected blood can be easily returned into the right atrium. The main circuit was composed of a centrifugal pump, an artificial membrane lung, and a filter. A reservoir with a roller pump was connected to the main circuit via a filter. Extracorporeal circulation was established by right atrial drainage via the femoral vein and femoral arterial return. On aortic cross-clamping, systemic blood pressure was controlled by activating the roller pump in reverse rotation and shifting the body blood into the reservoir temporarily. For a small amount of bleeding after aortotomy, the reservoir blood was returned via the femoral artery by activating the roller pump in normal rotation. When a large amount of bleeding was present making the systemic blood pressure fall, the main circuit was clamped just distal to the centrifugal pump and reservoir blood was directly returned to the right atrium to maintain systemic pressure. Confirming that bleeding was reduced, the clamp distal to the centrifugal pump was gradually released and blood was delivered to both the right atrium and the femoral artery. We believe that our system is a highly beneficial modality.

Aged↗