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1.
Osteoporos Int ; 32(2): 233-241, 2021 Feb.
Article in English | MEDLINE | ID: mdl-32820370

ABSTRACT

The mortality risk showed a positive correlation as the number of subsequent fractures increased. Hip fracture showed the greatest association with mortality risk, followed by vertebral fracture. For the combination of hip and vertebral fracture, a hip fracture after a vertebral fracture showed the highest mortality risk. INTRODUCTION: It is unclear whether subsequent fractures or a certain location and sequence of subsequent fractures are associated with mortality risk in the elderly. We aimed to investigate the relationship between subsequent fractures and mortality risk. METHODS: Using the Korean National Health Insurance Research Database, we analyzed the cohort data of 24,756 patients aged > 60Ā years who sustained fractures between 2002 and 2013. Cox regression was used to assess the mortality risk associated with the number, locations, and sequences of subsequent fractures. RESULTS: Mortality hazard ratios (HRs) for women and men were shown to be associated with the number of subsequent fractures (one, 1.63 (95% confidence interval [CI], 1.48-1.80) and 1.42 (95% CI, 1.28-1.58); two, 1.75 (95% CI, 1.47-2.08) and 2.03 (95% CI, 1.69-2.43); three or more, 2.46(95% CI, 1.92-3.15) and 1.92 (95% CI, 1.34-2.74), respectively). For women, the mortality risk was high when hip (HR, 2.49; 95% CI, 1.80-3.44) or vertebral (HR, 1.40; 95% CI, 1.03-1.90) fracture occurred as a second fracture. Compared with a single hip fracture, there was a high mortality risk in the group with hip fracture after the first vertebral fracture (HR, 2.90; 95% CI, 1.86-4.54), followed by vertebral fracture after the first hip fracture (HR, 1.90; 95% CI, 1.12-3.22). CONCLUSION: The mortality risk showed a positive correlation as the number of subsequent fractures increased. Hip fracture showed the greatest association with mortality risk, followed by vertebral fracture. For the combination of hip and vertebral fracture, a hip fracture after a vertebral fracture showed the highest mortality risk.


Subject(s)
Hip Fractures , Spinal Fractures , Aged , Cohort Studies , Female , Humans , Male , Proportional Hazards Models , Risk Factors , Spine
2.
Nano Lett ; 10(4): 1398-404, 2010 Apr 14.
Article in English | MEDLINE | ID: mdl-20196552

ABSTRACT

In 1908, Gustav Mie solved Maxwell's equations to account for the absorption and scattering of spherical plasmonic particles. Since then much attention has been devoted to the size dependent optical properties of metallic nanoparticles. However, ensemble measurements of colloidal solutions generally only yield the total extinction cross sections of the nanoparticles. Here, we show how Mie's prediction on the size dependence of the surface absorption and scattering can be probed separately for the same gold nanoparticle by using two single particle spectroscopy techniques, (1) dark-field scattering and (2) photothermal imaging, which selectively only measure scattering and absorption, respectively. Combining the optical measurements with correlated scanning electron microscopy furthermore allowed us to measure the size of the spherical gold nanoparticles, which ranged from 43 to 274 nm in diameter. We found that even though the trend predicted by Mie theory is followed well by the experimental data over a large range of nanoparticle diameters, for small size variations changes in scattering and absorption intensities are dominated by factors other than those considered by Mie theory. In particular, spectral shifts of the plasmon resonance due to deviations from a spherical particle shape alone cannot explain the observed variation in absorption and scattering intensities.


Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Nanotechnology/methods , Surface Plasmon Resonance/methods , Particle Size , Surface Properties
3.
Transplant Proc ; 40(5): 1353-6, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18589104

ABSTRACT

BACKGROUND: Epoxyeicosatrienoic acids (EETs) are endothelium-derived hyperpolarizing factors that contribute renal protective actions. The aim of this study was to identify the association between genetic variations in soluble epoxide hydrolase (EPHX2, EET-metabolizing enzyme) and kidney allograft dysfunction. MATERIALS AND METHODS: Data from 204 kidney transplant donor-recipient pairs were examined for polymorphisms of exon 8 (R287Q, rs751141 G/A) and 3' untranslated region (3' UTR, rs1042032 A/G) of the EPHX2 gene and correlated with clinical data. RESULTS: The mean duration of follow-up for recipients was 58 +/- 45.3 months who were 39 +/- 11.8 years old at the time of operation and displayed estimated glomerular filtration rate (eGFR) of 68 +/- 16.5 mL/min/1.73 m2 at 1 month after transplantation. AA, AG, and GG genotype frequencies in 3' UTR were 28%, 55%, and 16%, respectively. Twenty-one recipients experienced allograft dysfunction with eGFR <30 mL/min/1.73 m2; 10 had AA genotype of rs1042032 polymorphism (chi-square test; A/A vs A/G+G/G; P = .04). Recipients without rs1042032 polymorphism variant allele showed a significant risk for allograft dysfunction (A/A vs A/G+G/G; P = .04; odds ratio, 2.65; 95% confidence interval [CI], 1.03-6.81). Multivariate analysis of the characteristics of patients using a Cox proportional hazard model showed that the AA genotype of rs1042032 polymorphism was predictive of allograft dysfunction (Hazard Ratio = 3.26; P = .04; 95% CI, 1.08-9.59). CONCLUSION: The present study suggested that the presence of the rs1042032 variant allele in EPHX2 was associated with a protective role for allograft function.


Subject(s)
Epoxide Hydrolases/genetics , Genetic Variation , Kidney Transplantation/physiology , 3' Untranslated Regions/genetics , Adult , Arachidonic Acids/metabolism , Exons , Follow-Up Studies , Humans , Middle Aged , Treatment Outcome
4.
Transplant Proc ; 50(4): 1041-1044, 2018 May.
Article in English | MEDLINE | ID: mdl-29731063

ABSTRACT

Although a nationwide activation system has been developed to increase deceased donor kidney transplantation (DDKT), there is still enormous discrepancy between transplant need and deceased donor supply in Korea, and therefore waiting time to DDKT is still long. We need to determine the current status of waiting time and the risk factors for long waiting time. We retrospectively analyzed the medical records of the patients on the wait list for DDKT at the Seoul National University Hospital from 2000 to 2017. Among 2,211 wait-listed patients, 606 (27.5%) received DDKT and mean waiting time to DDKT was 45 months. Among them, blood type A was most prevalent (35.6%) and type AB was the least (14.0%). Panel-reactive assay (PRA) was positive in 59 (11.0%) in the first transplant group and 25 (35.0%) in retransplant group. Waiting time in PRA-positive recipients was 63 and 66 months in the first transplant group and retransplant group, respectively. However, waiting time for patients with negative PRA was 42.8 months. Waiting time was shorter in blood type AB (39 months) than other types (46 months). Waiting time was the shortest in children and adolescents. Among patients who were still on the wait list, retransplantation candidates, especially with PRA higher than 50%, had longer waiting time than first transplant candidates. In conclusion, non-AB blood type, positive PRA, and adult age were significantly associated with long waiting time. Therefore, it is necessary to establish a management strategy such as tailored desensitization for highly sensitized patients on the wait list to reduce their waiting time.


Subject(s)
Blood Group Incompatibility , Kidney Transplantation/methods , Waiting Lists , Adolescent , Adult , Child , Female , Humans , Kidney Transplantation/adverse effects , Male , Republic of Korea , Retrospective Studies , Time Factors , Tissue Donors/supply & distribution , Transplants/supply & distribution
5.
Transplant Proc ; 39(10): 3061-4, 2007 Dec.
Article in English | MEDLINE | ID: mdl-18089322

ABSTRACT

Although preemptive transplantation of kidneys from living donors without the previous initiation of dialysis is associated with longer allograft survival in a USRDS cohort, the effect of pretransplantation dialysis on graft outcome is still controversial in Korea. The purpose of this study was to evaluate the differential effects on long-term outcomes of living donor kidney transplantation according to initiation of dialysis and its duration or no dialysis. We performed a retrospective cohort study of 494 patients who received a first kidney transplant from a living donor between 1990 and 2006. The mean duration for dialysis was 14.5+/-22.2 months. The 10-year patient survival of 98.0% in the preemptive group was not significantly higher than the dialysis group (91.2%, P>.05). However, 10-year graft survival was higher in the preemptive than the dialysis group (preemptive 94.4%, dialysis 76.5%; P<.05). The differential effect of pretransplant dialysis either by hemodialysis or peritoneal dialysis was not significant, although peritoneal dialysis as a pretransplant treatment seemed to be beneficial on long-term graft survival (5-year graft survival; peritoneal 94.8% and hemodialysis 89.2%). The duration of dialysis did not affect graft survival in our study cohort. In conclusion, we suggest that preemptive transplantation should be applied to eligible patients.


Subject(s)
Graft Survival/physiology , Kidney Transplantation/physiology , Adolescent , Adult , Aged , Consanguinity , Female , Follow-Up Studies , Humans , Kidney Transplantation/mortality , Male , Middle Aged , Patient Selection , Retrospective Studies , Survival Analysis , Survivors , Time Factors , Treatment Outcome
6.
Circulation ; 104(9): 976-8, 2001 Aug 28.
Article in English | MEDLINE | ID: mdl-11524387

ABSTRACT

BACKGROUND: The early diastolic velocity of the mitral annulus (E') is reduced in patients with diastolic dysfunction and increased filling pressures. Because transmitral inflow early velocity (E) increases progressively with higher filling pressures, E/E' has been shown to have a strong positive relationship with pulmonary capillary wedge pressure (PCWP) and left ventricular end-diastolic pressure. However, previous studies have primarily involved patients without a pericardial abnormality. In constrictive pericarditis (CP), E' is not reduced, despite increased filling pressures. This study evaluated the relationship between E/E' and PCWP in patients with CP. METHODS AND RESULTS: We studied 10 patients (8 men; mean age, 64+/-7 years) with surgically confirmed CP. Doppler echocardiography was performed to measure early and late diastolic transmitral flow velocities. Tissue Doppler echocardiography was performed to measure E'. PCWP was measured with right heart catheterization. All patients were in sinus rhythm. Mean E and E' were 91+/-15 cm/s and 11+/-4 cm/s, respectively. Mean PCWP was 25+/-6 mm Hg. E' was positively correlated with PCWP (r=0.69, P=0.027). There was a significant inverse correlation between E/E' and PCWP (r=-0.74, P=0.014). Despite high left ventricular filling pressures, E/E' (mean, 9+/-4) was <15 in all but 1 patient. CONCLUSIONS: Paradoxical to the positive correlation between E/E' and PCWP in patients with myocardial disease, an inverse relationship was found in patients with CP.


Subject(s)
Mitral Valve/physiopathology , Pericarditis, Constrictive/physiopathology , Pulmonary Wedge Pressure , Aged , Blood Flow Velocity , Echocardiography, Doppler , Female , Heart Ventricles/physiopathology , Hemodynamics , Humans , Male , Middle Aged , Pericarditis, Constrictive/pathology
7.
Am J Cardiol ; 85(8): 986-91, 2000 Apr 15.
Article in English | MEDLINE | ID: mdl-10760340

ABSTRACT

A large left atrial (LA) v. wave can be observed in patients with pure mitral stenosis (MS) because of decreased LA compliance. Few data are available regarding the relation between the magnitude of the LA v wave and pulmonary artery pressure in MS. We hypothesized that pulmonary artery pressure may be higher in patients with decreased LA compliance and thus a large v. wave. We analyzed the right-sided cardiac and transseptal catheterization data in 113 patients (16 men and 97 women, mean age 39 years) with pure rheumatic MS in sinus rhythm. Peak systolic, diastolic, and mean pulmonary artery pressures were measured with right-sided cardiac catheterization. The magnitude of LA a and v. waves were measured through transseptal catheterization. Two-dimensional and Doppler echocardiography were also performed to measure LA size, mitral valve area, mean mitral gradient, and valvular regurgitation. Multiple regression analysis was performed to identify the most important factor in the determination of pulmonary artery pressure. A large v wave, defined if peak v wave height exceeded the mean LA pressure by > or =10 mm Hg, was observed in 43 of 113 patients (38%). Increased pulmonary artery systolic pressure (> or =50 mm Hg) was observed in 38 patients (34%). Univariate analysis showed that the factors associated with increased pulmonary artery systolic pressure were smaller mitral valve area, higher mean mitral gradient, higher mean LA pressure, and higher LA v. wave; among them, LA v wave (p <0. 001) and mean mitral gradient (p<0.001) were significant independent factors for pulmonary artery systolic pressure in multivariate analysis. In conclusion, in patients with pure MS and sinus rhythm, the magnitude of the LA v. wave is strongly associated with pulmonary artery pressure. This finding may suggest that LA compliance is a major contributing factor determining pulmonary artery pressure in pure MS.


Subject(s)
Atrial Function , Mitral Valve Stenosis/physiopathology , Pulmonary Artery/physiology , Adult , Blood Pressure/physiology , Cardiac Catheterization , Catheterization , Echocardiography , Echocardiography, Doppler , Female , Humans , Hypertension, Pulmonary/diagnosis , Hypertension, Pulmonary/etiology , Male , Mitral Valve Stenosis/complications , Regression Analysis
8.
Am J Cardiol ; 83(11): 1579-82, A8, 1999 Jun 01.
Article in English | MEDLINE | ID: mdl-10363879

ABSTRACT

We examined the relation between the echocardiographic morphology of cardiac myxoma and systemic embolism in 25 patients. Two distinct types of myxoma could be identified by echocardiography: round type characterized by solid and round shape with nonmobile surface (n = 13, 52%), and polypoid type characterized by soft and irregular shape with mobile surface (n = 12, 48%); multiple regression analysis revealed the polypoid type of tumor was the only independent predictor of systemic embolism (p = 0.0029).


Subject(s)
Echocardiography , Embolism/pathology , Heart Atria , Heart Neoplasms/diagnostic imaging , Heart Neoplasms/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Coronary Vessels/diagnostic imaging , Coronary Vessels/pathology , Embolism/diagnostic imaging , Female , Heart Neoplasms/surgery , Humans , Male , Middle Aged
9.
Am J Cardiol ; 87(5): 669-71, A11, 2001 Mar 01.
Article in English | MEDLINE | ID: mdl-11230864

ABSTRACT

When the results of transesophageal echocardiography was regarded as the gold standard for detecting a patent foramen ovale (PFO) in 136 consecutive patients referred for evaluation of cardiac source of embolism, transthoracic harmonic imaging using saline contrast was superior to fundamental imaging in accuracy for detecting a PFO (sensitivity, 22.5%; specificity [p < 0.05] and sensitivity, 100%; specificity 100%, respectively.)


Subject(s)
Echocardiography , Embolism, Paradoxical/diagnostic imaging , Heart Septal Defects, Atrial/diagnostic imaging , Image Enhancement , Adult , Aged , Aged, 80 and over , Echocardiography, Transesophageal , Female , Humans , Male , Middle Aged , Predictive Value of Tests
10.
Ann Thorac Surg ; 67(1): 226-8, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10086555

ABSTRACT

We examined a case of endocardial tuberculoma at the proximal superior vena cava and the right atrium in a 17-year-old male patient. He had frequent palpitations and general weakness for about 7 months and was referred for evaluation of incessant atrial tachyarrhythmia. Results of echocardiography and magnetic resonance imaging showed an intracardiac mass, which was excised using cardiopulmonary bypass. Histology of the mass was consistent with the diagnosis of tuberculoma. The patient's postoperative course was uneventful and he was discharged with antituberculous medication. Five months after the operation, the patient was well without tachycardia, and follow-up echocardiography showed complete disappearance of the mass.


Subject(s)
Tuberculoma/surgery , Tuberculosis, Cardiovascular/surgery , Adolescent , Echocardiography, Transesophageal , Humans , Male , Tuberculoma/diagnosis , Tuberculosis, Cardiovascular/diagnosis
11.
J Am Soc Echocardiogr ; 14(11): 1100-6, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11696835

ABSTRACT

Mitral stenosis (MS) and mitral regurgitation (MR) are the most frequent conditions that cause a dilation and dysfunction of the left atrial appendage (LAA). Despite similarly dilated LAA in patients with MS and MR, the incidence of LAA thrombi and the risk of thromboembolism is different between these patients. The purpose of this study was to characterize the filling pattern of LAA by using intravenous administration of perfluorocarbon-exposed dextrose albumin (PESDA) during transesophageal echocardiographic examination in patients with MS and MR. Twenty-four patients with moderate to severe MS, 12 patients with severe MR, and a control group including 30 patients with conditions other than mitral valve disease underwent transesophageal echocardiographic examination with an intravenous bolus injection of PESDA. LAA emptying and filling velocities and maximal and minimal areas of LAA and LAA ejection fraction were measured. Digital gray-scale intensity (GSI) of the left atrial (LA) and LAA cavity after PESDA injection was measured by off-line analysis. Compared with control patients, patients with MS or MR had larger maximal and minimal areas of LAA and reduced LAA ejection fraction. LAA peak emptying flow velocity was significantly lower in patients with MS compared with those of MR or control patients. LAA peak filling velocity was significantly lower in patients with MS compared with that of control patients. However, there was no significant difference of LAA peak filling velocity between the patients with MS and MR. There was no significant difference of GSI ratio of LAA and LA between patients with MR and control patients; however, GSI ratio of LAA and LA was significantly lower in patients with MS compared with that of MR. The incidence of LAA spontaneous echo contrast and LAA thrombi in patients with MS was significantly higher than that of the patients with MR and control subjects (P <.005). Despite similarly dilated LAA area and depressed contractile function of LAA in patients with MS and MR compared with control patients, profoundly impaired LAA filling with resultant flow stasis was demonstrated by contrast echocardiography in patients with MS. These findings may explain the higher incidence of LAA spontaneous echo contrast and thrombus in patients with MS.


Subject(s)
Atrial Appendage/physiopathology , Mitral Valve Insufficiency/physiopathology , Mitral Valve Stenosis/physiopathology , Aged , Atrial Appendage/diagnostic imaging , Case-Control Studies , Contrast Media/administration & dosage , Coronary Thrombosis/etiology , Coronary Thrombosis/physiopathology , Echocardiography, Transesophageal , Female , Fluorocarbons/administration & dosage , Glucose/administration & dosage , Humans , Injections, Intravenous , Male , Middle Aged , Mitral Valve Insufficiency/complications , Mitral Valve Stenosis/complications , Reference Values , Serum Albumin/administration & dosage , Serum Albumin, Human , Stroke Volume
12.
J Am Soc Echocardiogr ; 11(4): 393-6, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9571591

ABSTRACT

Pulmonary vein stenosis is a rare condition that usually is congenital in origin; it is almost invariably fatal in its bilateral and severe forms. It is often overlooked, however, during clinical examination, routine echocardiography, and even at cardiac catheterization. This report describes the pulsed Doppler, color flow echocardiography, and hemodynamic findings of bilateral pulmonary vein stenosis that accompany ventricular septal defect and atrial septal defect corrected by surgery.


Subject(s)
Cardiac Catheterization , Pulmonary Veins/abnormalities , Pulmonary Veins/diagnostic imaging , Adult , Constriction, Pathologic , Female , Heart Septal Defects/complications , Heart Septal Defects/diagnosis , Heart Septal Defects/diagnostic imaging , Humans , Ultrasonography, Doppler, Color , Ultrasonography, Doppler, Pulsed
13.
J Am Soc Echocardiogr ; 11(10): 992-6, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9804108

ABSTRACT

Pseudoaneurysm of the aorta usually occurs as a complication of nonpenetrating trauma or deceleration injuries. Spontaneous pseudoaneurysm of the aorta is, however, extremely rare. Pulmonary veins can be affected in this situation because of the anatomic proximity. However, it is often overlooked during clinical examination, during routine echocardiography, and even at invasive angiography. This report describes the importance of transesophageal echocardiography in the detection of pulmonary vein compression, which is not suspected during other noninvasive and invasive diagnostic tests, in a patient with spontaneous pseudoaneurysm of the descending thoracic aorta.


Subject(s)
Aneurysm, False/complications , Aortic Aneurysm, Thoracic/complications , Echocardiography, Transesophageal , Pulmonary Veno-Occlusive Disease/diagnostic imaging , Adult , Aneurysm, False/diagnostic imaging , Angiography, Digital Subtraction , Aortic Aneurysm, Thoracic/diagnostic imaging , Humans , Male , Pulmonary Veno-Occlusive Disease/etiology
14.
J Am Soc Echocardiogr ; 13(9): 849-54, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10980088

ABSTRACT

BACKGROUND: Spontaneous echo contrast (SEC) of the left atrium is associated with increased risk of thromboembolism in patients with mitral stenosis (MS). The determination of the presence and severity of left atrial (LA) SEC is of prognostic importance in these patients. Harmonic imaging (HI), a novel echocardiographic technique that differs from conventional fundamental imaging (FI) in that it involves transmitting ultrasound at one frequency and receiving at twice the transmitted frequency, produces better endocardial border definition and myocardial opacification. However, there are no data about its value for the detection of LA SEC. The purpose of this study was to investigate the utility of transthoracic noncontrast tissue HI in the detection of LA SEC in patients with MS. METHODS: Seventy-four consecutive patients with MS (49 women, mean age 51 years) underwent standard transthoracic echocardiography (TTE) in both HI and FI modes and transesophageal echocardiography (TEE) to determine the presence and severity of LA SEC. Left atrial SEC was graded by TEE as either mild (only seen at high gain) or severe (visible in the entire left atrium at normal gain control of the equipment). The control group comprised 30 patients randomly selected from patients who did not have LA SEC at the TEE examination. RESULTS: Atrial fibrillation was found in 46 patients (62.2%). The mean mitral valve area and mean mitral gradient were 1.0+/-0.3 cm(2) and 8.2+/-4.1 mm Hg, respectively. Nine patients (12.2%) had episodes of systemic embolism; 8 had stroke, and 1 had peripheral embolism. Left atrial thrombus was found in 11 patients (14.9%) by TEE. Left atrial SEC was present in all but one patient by TEE (mild in 35 patients, severe in 38). Fundamental imaging with TTE, however, revealed LA SEC in only 5 (6.8%) of the 73 patients. In contrast, with HI, LA SEC could be detected in 63 (86.3%) patients. In the detection of severe LA SEC, the sensitivities of FI and HI were 13.2% (5/38) and 100% (38/38), respectively. Left atrial SEC was not observed in control subjects by either FI or HI. CONCLUSIONS: Transthoracic HI significantly enhances the detection of LA SEC in patients with MS.


Subject(s)
Echocardiography/methods , Heart Atria/diagnostic imaging , Image Enhancement , Mitral Valve Stenosis/diagnostic imaging , Adolescent , Adult , Aged , Echocardiography, Transesophageal , Female , Humans , Male , Middle Aged , Sensitivity and Specificity
15.
Spine (Phila Pa 1976) ; 25(14): 1843-7, 2000 Jul 15.
Article in English | MEDLINE | ID: mdl-10888955

ABSTRACT

STUDY DESIGN: A prospective study of 87 patients who underwent unilateral or bilateral pedicle screw fixation. OBJECTIVES: To determine whether unilateral pedicle screw fixation is comparable with bilateral fixation in one- or two-segment lumbar spinal fusion. SUMMARY OF BACKGROUND DATA: Clinical results for unilateral variable screw placement instrumentation in isolated L4-L5 fusion have been reported to be as good as those for bilateral instrumentation. However, unilateral instrumentation may not be recommended for multilevel fusion. METHODS: Eighty-seven patients were assigned to either unilateral (n = 47) or bilateral (n = 40) pedicle screw instrumentation groups. Two kinds of pedicle screw system (Moss Miami, DePuy, Warsaw, IN, and Steffee VSP, AcroMed, Cleveland, OH) were used. Operating time, blood loss, duration of hospital stay, clinical outcomes, fusion rates, complication rates, and medical expenses were studied and tested with independent sample t test and chi2 test. RESULTS: There were no significant differences between the two groups in blood loss, clinically satisfactory results, fusion rate, and complication rate. There were significant differences in duration of operating time, duration of hospital stay, and medical expenses. The number of fusion segments or kinds of instrumentation did not affect the fusion rate or clinical outcomes. CONCLUSIONS: Unilateral pedicle screw fixation was as effective as bilateral pedicle screw fixation in lumbar spinal fusion independent of the number of fusion segments (one or two segments) or pedicle screw systems. Based on the results of this study, unilateral fixation could be used in two-segment lumbar spinal fusion.


Subject(s)
Bone Screws , Internal Fixators , Lumbar Vertebrae/surgery , Spinal Fusion/instrumentation , Adult , Aged , Blood Loss, Surgical , Female , Follow-Up Studies , Hospital Costs , Humans , Length of Stay , Lumbar Vertebrae/diagnostic imaging , Male , Middle Aged , Postoperative Complications , Prospective Studies , Radiography , Spinal Fusion/adverse effects , Spinal Fusion/economics , Time Factors , Treatment Outcome
16.
Spine (Phila Pa 1976) ; 26(22): 2498-503, 2001 Nov 15.
Article in English | MEDLINE | ID: mdl-11707718

ABSTRACT

STUDY DESIGN: Flexibility tests and finite element analyses were performed for the biomechanical evaluation of diagonal transfixation in pedicle screw instrumentation. OBJECTIVE: To assess the biomechanical advantages of diagonal transfixation compared with conventional horizontal transfixation. SUMMARY AND BACKGROUND DATA: A few pedicle screw instrumentation systems allow the use of cross-links in the diagonal direction. Such a diagonal transfixation is anticipated to improve the surgical construct stability, but its biomechanical qualities have not been completely evaluated. METHODS: Flexibility tests were performed on 10 calf lumbar spines (L2-L5). Specimens were subjected to pure moments up to 8.2 Nm in flexion, extension, lateral bending, and extension while the resulting movements of L3 and L4 were measured by a three-dimensional motion analysis system. The tested cases included (1) intact, (2) pedicle screw fixation without transfixation after total removal of the L3-L4 disc, (3) pedicle screw fixation with diagonal transfixation, and (4) pedicle screw fixation with horizontal transfixation. Three-dimensional finite element models of the tested surgical constructs were also developed by use of three-dimensional beam elements to investigate the effect of diagonal transfixation and horizontal transfixation on the construct stability and the corresponding stress changes in the screws. RESULTS: When compared with no transfixation, horizontal transfixation significantly improved the lateral bending and axial rotation stability by 15.7% and 13.9%, respectively, but there was no improvement of stability in flexion and extension. By contrast, diagonal transfixation significantly improved the flexion and extension stability by 12% and 10.7%, respectively, but not the lateral bending and axial rotation stability in comparison with no transfixation. Comparison between horizontal transfixation and diagonal transfixation showed that the stabilizing effect of diagonal transfixation was greater in flexion and extension (13% and 11%, P < 0.01) than that of horizontal transfixation but smaller in lateral bending (11%, P < 0.05) and axial rotation (6.6%, P > 0.1). Finite element model predictions of the motion changes were similar to the changes observed in flexibility tests. In horizontal transfixation, the load changes, compared with no transfixion, were a 0.02% increase in flexion-extension, a 27.5% increase in lateral bending, and a 58% decrease in axial rotation, and the magnitudes of the moments applied on both the right and left pedicle screws were identical. However, when diagonal transfixation was achieved by connecting the left superior screw and the right inferior screw, the loads in the left screw were increased by 11.5% in flexion-extension, 43.6% in lateral bending, and 7.9% in axial rotation, whereas the loads in the right screw were decreased by 10.9% in flexion-extension, increased by 0.06% in lateral bending, and decreased by 18.1% in axial rotation. CONCLUSIONS: The results of this study showed that diagonal transfixation provides more rigid fixation in flexion and extension but less in lateral bending and axial rotation in comparison with horizontal transfixation. Furthermore, greater stresses in the pedicle screws were predicted in the diagonal transfixation model. These limitations of diagonal transfixation should be considered carefully for clinical application.


Subject(s)
Bone Screws , Lumbar Vertebrae/physiopathology , Lumbar Vertebrae/surgery , Orthopedic Fixation Devices , Animals , Biomechanical Phenomena , Cattle , Finite Element Analysis , Models, Biological , Motion , Orthopedics/methods , Rotation , Stress, Mechanical
17.
Spine (Phila Pa 1976) ; 25(17): 2187-90, 2000 Sep 01.
Article in English | MEDLINE | ID: mdl-10973401

ABSTRACT

STUDY DESIGN: A retrospective follow-up study. OBJECTIVES: To review and analyze the sexual function of patients who have sustained lumbar fractures with incomplete paraparesis. SUMMARY OF BACKGROUND DATA: As a result of advances in surgical techniques, most patients with lumbar fractures have significant recovery of neurologic status. Because motor functions are important to patients, most of the studies have concentrated their analyses on motor recovery. Many patients who have almost completely recovered motor function, however, may have sexual dysfunction, especially men. METHODS: Forty-three patients with lumbar fractures that resulted in incomplete paraparesis were analyzed. American Spinal Injury Association motor index points were determined for each patient before and after surgery and used for comparison between American Spinal Injury Association motor index and international index of erectile function score. Eleven male patients who reported sexual dysfunction were evaluated by using Rigiscan. RESULTS: During the follow-up period, 42 patients showed neurologic recovery. Average improvement of American Spinal Injury Association motor score was 13. 1 and average international index of erectile function score was 45. Average improvement of American Spinal Injury Association motor score for patients who had not reported sexual dysfunction was 12.5, and average international index of erectile function score was 52. For 11 patients in the sexual dysfunction group, preoperative motor score was 28.0, and average improvement of score was 14.9. Nocturnal penile tumescence monitoring results were abnormal in four cases. Averaged international index of erectile function score was 15. There was a statistically significant difference between the sexually healthy and dysfunctional groups in international index of erectile function score (P < 0.05), whereas no difference was noted in American Spinal Injury Association motor score. CONCLUSIONS: Neurologic recovery after lumbar fractures was improved. Regardless of neurologic recovery, most patients reported some disability, usually caused by pain and occasionally sexual dysfunction. Impairment of sexual function was present in four patients (9.3%). Although these patients may preserve psychiatric erection potential, they usually experienced sexual problems.


Subject(s)
Erectile Dysfunction/etiology , Lumbar Vertebrae/injuries , Paraparesis/complications , Paraparesis/etiology , Recovery of Function , Spinal Fractures/complications , Adult , Erectile Dysfunction/epidemiology , Erectile Dysfunction/surgery , Follow-Up Studies , Humans , Lumbar Vertebrae/surgery , Male , Middle Aged , Paraparesis/surgery , Retrospective Studies , Spinal Fractures/epidemiology , Spinal Fractures/surgery , Treatment Outcome
18.
Yonsei Med J ; 34(4): 352-5, 1993 Dec.
Article in English | MEDLINE | ID: mdl-8128740

ABSTRACT

Progeria, also known as Hutchinson-Gilford syndrome, is an extremely rare condition originally described by Hutchinson in 1886. Death results from cardiac complications in the majority of cases and usually occurs at an average age of fourteen years. We recently experienced a patient with progeria who died suddenly after symptomatic improvement with conservative treatment. A Doppler and two-dimensional echocardiographic study revealed an enlarged and hypertrophied left ventricle with reduced global systolic function and senile aortic calcific stenosis (peak systolic pressure gradient: 50 mmHg) with a moderate degree of aortic regurgitation. Doppler findings of restrictive hemodynamic suggest severe left ventricular dysfunction due to multiple influences from the aging process, coronary artery and valvular heart disease.


Subject(s)
Cardiovascular System/diagnostic imaging , Echocardiography, Doppler , Echocardiography , Progeria/diagnostic imaging , Adult , Cardiac Catheterization , Coronary Angiography , Humans , Male , Progeria/diagnosis
19.
Yonsei Med J ; 39(5): 446-52, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9821794

ABSTRACT

We analyzed Doppler echocardiographic data in 120 subjects with normal sinus rhythm; normals (NL, n = 60, ages 54.1 +/- 15.1) and essential hypertensive patients (HT, n = 60, ages 57.3 +/- 10.2). The IMP was calculated as follows: IMP = (ICT + IRT)/ET, ICT; isovolumic contraction time, IRT; isovolumic relaxation time, ET; ejection time. There were no significant differences in ejection fraction (EF), stroke volume index (SVI), cardiac index (CI), ET and ICT between NL and HT. There were, however, significant differences in deceleration time (DT), E/A ratio, IRT and the IMP between the two groups (199.5 +/- 45.6 msec vs 222.3 +/- 54.3 msec, p < 0.01; 1.4 +/- 0.7 vs 0.9 +/- 0.2, p < 0.01; 113.6 +/- 30.2 msec vs 134.2 +/- 29.6 msec, p < 0.01; 0.6 +/- 0.1 vs 0.8 +/- 0.3, p < 0.05). In HT, there were no differences in EF, SVI, CI, E/A ratio and DT between the NYHA I (Gp I, n = 36) and II (Gp II, n = 24) groups. However, ET of Gp II was significantly shorter than that of Gp I (259.4 +/- 43.5 msec vs 297.8 +/- 33.6 msec, p < 0.01). ICT, IRT and the IMP were significantly increased in Gp II, compared to those of Gp I (64.4 +/- 23.9 msec vs 89.4 +/- 46.2 msec, p < 0.05; 120.3 +/- 21.0 msec vs 155.2 +/- 28.5 msec, p < 0.001; 0.6 +/- 0.2 vs 1.0 +/- 0.4, p < 0.001). There were no differences in heart rate and mean blood pressure between Gp I and Gp II (70.9 +/- 11.4/min vs 66.3 +/- 11.4/min, p > 0.05; 138.4 +/- 21.2 mmHg vs 131.3 +/- 19.9 mmHg, p > 0.05). These data suggest that the IMP may be a useful parameter and an early indicator of left ventricular dysfunction in essential hypertensive patients with normal systolic function.


Subject(s)
Echocardiography, Doppler , Hypertension/diagnostic imaging , Hypertension/physiopathology , Ventricular Function, Left/physiology , Adult , Aged , Diastole/physiology , Female , Humans , Male , Middle Aged , Systole/physiology
20.
Yonsei Med J ; 39(1): 61-6, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9529987

ABSTRACT

Left ventricular systolic function in hypertrophic cardiomyopathy (HCMP) does not usually deteriorate even in the end stage of the disease. However, occasionally cases of HCMP progress to a similar form of dilated cardiomyopathy (DCMP) with a decreased systolic function and dilated left ventricle. We report two cases of HCMP which progressed to DCMP during follow-up. Our cases have been documented by serial M-mode echocardiography which shows a prominent decrease in the left ventricular systolic function and a chamber enlargement of the left ventricle. There are various explanations of the pathogenesis of the functional and morphological myocardial deterioration of HCMP progressing to DCMP, and more cases should be studied to determine the pathogenesis and prevention of this end-stage feature of HCMP.


Subject(s)
Cardiomyopathy, Dilated/etiology , Cardiomyopathy, Hypertrophic/complications , Adolescent , Adult , Echocardiography , Follow-Up Studies , Humans , Male
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