Translational Research: Where Do We Go? / 신경중재치료의학

No abstract available.

Recent 10 Years' Trend Analysis of Inhaled Corticosteroids Prescription Rate and Severe Exacerbation Rate in Asthma Patients / 결핵및호흡기질환

BACKGROUND: Inhaled corticosteroids (ICSs) are the most essential medication for asthma control. Many reports suggest that the usage of ICSs improves not only the control of asthma symptoms but also prevents exacerbation. We investigated whether increases in ICS prescriptions are associated with decreases in asthma exacerbation in the clinical practice setting. METHODS: We retrospectively analyzed the database of adult asthma patients who had visited a tertiary referral hospital, the Asan Medical Center between January 2000 and December 2009. The number of emergency department (ED) visits, admissions, intensive care unit (ICU) care, deaths, and ICS prescriptions were analyzed to evaluate the time trend of asthma exacerbation as a function of the ICS prescription rate during the ten years. RESULTS: The numbers of ED visits, admissions, and episodes of ICU care decreased during the ten years (p<0.001, p=0.033, p=0.001, respectively) while the number of ICS prescriptions increased (p<0.001). We found a correlation between the number of ICS prescriptions and the number of ED visits, admissions, or ICU care. For these outcomes, the correlation coefficients were r=-0.952, p<0.001; r=-0.673, p=0.033; r=-0.948, p<0.001, respectively. CONCLUSION: The number of ICS prescriptions increased during the past ten years while the number of asthma exacerbations decreased. Our results also showed a negative correlation between the ICS prescription rate and asthma exacerbation in the clinical practice setting. In other words, an increase in ICS prescription may be a major cause of a decrease in asthma exacerbations.

Formulation of a reference coordinate system of three-dimensional (3D) head and neck images: Part I. Reproducibility of 3D cephalometric landmarks / 대한치과교정학회지

The purpose of this study was to redefine the cephalometric landmarks in three-dimensional (3D) images, which are used in orthodontic cephalometric radiography, and to evaluate the reproducibility of each landmark for 3D cephalometric analysis. Eighteen CT scans were taken at the Department of Diagnostic Radiology at Seoul National University Dental Hospital and manipulated with V works 4.0 (Cybermed Inc., Seoul, Korea). The coordinate system was established using 7 reference points, with no more than 4 points on the same plane. These 7 points were generated as a volume model, the voxel size of which was 4 by 4 by 2 (threshold value = 639). The cephalometric landmarks were selected at the multiplanar reformation (MPR) window on the volume mode of V works 4.0. The selected landmarks were exported to V surgery (Cybermed Inc., Seoul, Korea) for the calculation of coordinate values. All the data were taken twice with a lapse of 2 weeks by one investigator. The reproducibility of each landmark was 0.17 ~ 1.21 mm in the x axis, 0.30 ~ 1.53 mm in the y axis, and 0.27 ~ 1.81 mm in the z axis. In all three axes, the range of error was similar. These error ranges were acceptable with regards to the pixel space and slice thickness. The most reproducible points were I points which were selected on the basis of the volume model. The least reproducible points were J points that were defined by sutures.

Three-dimensional analysis of soft and hard tissue changes after mandibular setback surgery in skeletal Class III patients / 대한치과교정학회지

The three-dimensional (3D) changes of bone, soft tissue and the ratio of soft tissue to bony movement was investigated in 8 skeletal Class III patients treated by mandibular setback surgery. CT scans of each patient at pre- and post-operative states were taken. Each scan was segmented by a threshold value and registered to a universal three-dimensional coordinate system, consisting of an FH plane, a mid-sagittal plane, and a coronal plane defined by PNS. In the study, the grid parallel to the coronal plane was proposed for the comparison of the changes. The bone or soft tissue was intersected by the projected line from each point on the gird. The coordinate values of intersected point were measured and compared between the pre- and post-operative models. The facial surface changes after setback surgery occurred not only in the mandible, but also in the mouth corner region. The soft tissue changes of the mandibular area were measured relatively by the proportional ratios to the bone changes. The ratios at the mid-sagittal plane were 77 ~ 102% (p < 0.05). The ratios at all other sagittal planes had similar patterns to the mid-sagittal plane, but with decreased values. And, the changes in the maxillary region were calculated as a ratio, relative to the movement of a point representing a mandibular movement. When B point was used as a representative point, the ratios were 14 ~ 29%, and when Pog was used, the ratios were 17 ~ 37% (p < 0.05). In case of the 83rd point of the grid, the ratios were 11 ~ 22% (p < 0.05).

Formulation of a reference coordinate system of three-dimensional head and neck images: Part II. Reproducibility of the horizontal reference plane and midsagittal plane / 대한치과교정학회지

This study was performed to investigate the reproducibility of the horizontal and midsagittal planes, and to suggest a stable coordinate system for three-dimensional (3D) cephalometric analysis. Eighteen CT scans were taken and the coordinate system was established using 7 reference points marked by a volume model, with no more than 4 points on the same plane. The 3D landmarks were selected on V works (Cybermed Inc., Seoul, Korea), then exported to V surgery (Cybermed Inc., Seoul, Korea) to calculate the coordinate values. All the landmarks were taken twice with a lapse of 2 weeks. The horizontal and midsagittal planes were constructed and its reproducibility was evaluated. There was no significant difference in the reproducibility of the horizontal reference planes. But, FH planes were more reproducible than other horizontal planes. FH planes showed no difference between the planes constructed with 3 out of 4 points. The angle of intersection made by 2 FH planes, composed of both Po and one Or showed less than 1 degrees difference. This was identical when 2 FH planes were composed of both Or and one Po. But, the latter cases showed a significantly smaller error. The reproducibility of the midsagittal plane was reliable with an error range of 0.61 to 1.93 degrees except for 5 establishments (FMS-Nc, Na-Rh, Na-ANS, Rh-ANS, and FR-PNS). The 3D coordinate system may be constructed with 3 planes; the horizontal plane constructed by both Po and right Or; the midsagittal plane perpendicular to the horizontal plane, including the midpoint of the Foramen Spinosum and Nc; and the coronal plane perpendicular to the horizontal and midsagittal planes, including point clinoidale, or sella, or PNS.

Development of an Intra-operative Navigation System Using an Optical Tracking System / 대한정형외과연구학회지

PURPOSE: The purposes of this study were to develop an intraoperative navigation system as the first step toward image-guided surgery and robotic surgery, and to evaluate its accuracy. MATERIALS AND METHODS: The navigation system was composed of an optical tracking system (Polaris, Northern Digital) and a personal computer. The registration error and target localization error of fiducial registration and surface registration were measured using a phantom. Each of the errors was measured 30 times, and the average values and the standard deviations were calculated. RESULTS: The registration error was 0.84 +/- 0.28 mm at fiducial registration and 0.81 +/- 0.21 mm at surface registration. The target localization error was 1.54 +/- 0.34 mm at fiducial registration and 1.46 +/- 0.32 mm at surface registration. CONCLUSION: We have developed an intraoperative navigation system using an optical tracker, and could assure ourselves that its accuracy is adequate for many orthopaedic surgeries. However, it still requires improvement in the accuracy and development of specific software and instruments for various operations.

A Robot Arm-type Navigation System for Pedicle Screw Placement: A Feasibility Study / 대한척추외과학회지

STUDY DESIGN: The study involved the development and accuracy testing of an intra-operative navigation system. OBJECTIVES: This study was undertaken to develop a navigation system using a robot arm-type three-dimensional digitizer. And, to apply the developed system to pedicle screw insertion, and to evaluate its accuracy. SUMMARY OF LITERATURE REVIEW: To the best of our knowledge, no navigation system has been developed using a robot armtype three-dimensional digitizer. MATERIALS AND METHODS: We have developed a navigator using a three-dimensional digitizer (Microscribe 3-D G2, Immersion, USA) supported by a personal computer. Four types of patient-to-image registration techniques were implemented. During navigation, the central axis of the robot arm's stylus and arm extension can be displayed over multi-planar and three-dimensional images, which are reconstructed from axial CT scan images. Registration errors and target localization errors of the navigation system were evaluated using a phantom made from a plastic lumbo-sacral bone model. The accuracy of pedicle screw insertion was also evaluated by placing 18 pedicle screws in such bone models. RESULTS: The registration error was 0.78 +/- 0.27 mm at fiducial registration and 0.76 +/- 0.24 mm at hybrid registration, and the target localization error was 1.34 +/- 0.32 mm at fiducial registration and 1.28 +/- 0.29 mm at hybrid registration. Of the 18 screws placed in the plastic bone models, one (6%) screw breached the pedicle wall. CONCLUSIONS: We have developed a robot arm-type three-dimensional digitizer-based navigation system for pedicle screw insertion, and found that its accuracy is equal or slightly better than that of optical tracker-based navigators.

Reduction of Metal Artifact around Titanium Alloy-based Pedicle Screws on CT Scan Images: An Approach using a Digital Image Enhancement Technique / 대한척추외과학회지

STUDY DESIGN: A study on the development of an algorithm to enhance computed tomographic images. OBJECTIVE: The purpose of this study was to develop an approach to reduce the metal artifact that appears around pedicle screws, and thus to facilitate the evaluation of pedicle screw positions on CT scan images. SUMMARY OF LITERATURE REVIEW: Metal artifact caused by pedicle screws significantly reduces the interpretability of computed tomography images. MATERIALS AND METHODS: We describe the development of an algorithm that processes CT scan images on a personal computer using a digital image enhancement technique. The algorithm improves CT images by transforming image pixel values using a proper transformation curve that takes into account the characteristic distribution pattern of metal artifact caused by pedicle screws made of titanium alloys. We implemented this algorithm in a program that reconstructs the resulting images in arbitrary planes and in axial, coronal, and sagittal planes. The software was tested with spiral CT scan images of 38 patients containing 190 pedicle screws. RESULTS: In all test cases, our algorithm generated images with less metal artifact, better soft tissue visualization and clearer screw outlines than conventional bone setting. In addition, images reconstructed in arbitrary planes increase the convenience and confidence of localizing screw positions. CONCLUSIONS: The algorithm effectively decreases metal artifact and improved pedicle screw localization.

A Case of Female Epispadias / 대한비뇨기과학회지

Female epispadias is an uncommon congenital anomaly in genitourinary tract. We experienced a case of female epispadias with total urinary incontinence which was improved with periurethral injection of Glutaraldehyde Cross-Linked Collagen(GAX-Collagen) into the area of the bladder neck. The procedure was simple to perform and without significant complications. Herein we report a case of female epispadias in 29-year old female.

Initial Experience of the Effect of Laser CHRP (Coagulation and Hemostatic Resection of the Prostate) for Benign Prostatic Hyperplasia / 대한비뇨기과학회지

Laser CHRP (coagulation and hemostatic resection of the prostate) is a new acceptable treatment modality for benign prostatic hyperplasia. A total of 14 patients with symptomatic bladder outlet obstruction due to benign prostatic hyperplasia was entered into a prospective trial of laser prostatectomy performed with the right- angle firing neodymium: YAG laser fiber and the contact tip firing neodymium: YAG laser fiber at 60 watts power setting. Mean estimated prostatic weight was 36.3gm. Six patients (43%) were in urinary retention requiring catheterization before treatment. Mean energy delivery was 34,442 joules (range 25,360 to 45,000) with a mean operative time of 41 minutes. Efficacy of treatment was assessed at 1, 6 and 12 months postoperatively by Madsen symptom scores, peak urinary flow rates and ultrasonic assessment of prostatic volume. At preoperative baseline the mean symptom score was 19.9, mean peak urinary flow rate 8.6cc per second, and mean ultrasonic assessment of prostatic volume 36.3gm. At 1 year postoperatively mean symptom score was 6.1, mean peak urinary flow rate was 18.3cc per second and mean ultrasonic assessment of prostatic volume was 26.4 gm. One patient required retreatment for residual tissue. There was one bladder neck contracture requiring incision.