Changes of Prosapogenin Components in Tienchi Seng (Panax notoginseng) by Ultrasonic Thermal Fusion Process

The purpose of this study is to develop a new method of producing tienchi seng (notoginseng, Panax notoginseng) extracts featuring high concentrations of the ginsenoside Rg3, Rg5, and Rg6, special components of Korean red ginseng. The chemical transformation from ginseng saponin glycosides to prosapogenin was analyzed by HPLC. Tienchi seng was heat-processed at 100 o C and the optimum conditions were identified. The highest concentrations of total saponin (29.723%) and the ginsenoside Rg3 (1.769%), Rg5 (5.979%), and Rg6 (13.473%) were produced at 48 hours. Also, when tienchi seng was subjected to the ultrasonic thermal fusion (100 o C) process, the concentrations of total saponin (30.578%), ginsenoside Rg3 (2.392%), Rg5 (6.614%), and Rg6 (13.017%) were highest at 36 hours. On the other hand, the 2-hour heat-processed extract and 2-hour ultrasonic thermal fusion-processed extract did not contain ginsenoside Rg3, Rg5, and Rg6. The ultrasonic thermal fusion process had an extraction yield that was approximately 1.26 times greater than that of the heat process. These results indicate that the highly functional tienchi seng extracts created through the ultrasonic thermal fusion process are more industrially useful than those produced using the heat process.

Changes of Prosapogenin Components in Tienchi Seng (Panax notoginseng) by Ultrasonic Thermal Fusion Process

The purpose of this study is to develop a new method of producing tienchi seng (notoginseng, Panax notoginseng) extracts featuring high concentrations of the ginsenoside Rg3, Rg5, and Rg6, special components of Korean red ginseng. The chemical transformation from ginseng saponin glycosides to prosapogenin was analyzed by HPLC. Tienchi seng was heat-processed at 100 o C and the optimum conditions were identified. The highest concentrations of total saponin (29.723%) and the ginsenoside Rg3 (1.769%), Rg5 (5.979%), and Rg6 (13.473%) were produced at 48 hours. Also, when tienchi seng was subjected to the ultrasonic thermal fusion (100 o C) process, the concentrations of total saponin (30.578%), ginsenoside Rg3 (2.392%), Rg5 (6.614%), and Rg6 (13.017%) were highest at 36 hours. On the other hand, the 2-hour heat-processed extract and 2-hour ultrasonic thermal fusion-processed extract did not contain ginsenoside Rg3, Rg5, and Rg6. The ultrasonic thermal fusion process had an extraction yield that was approximately 1.26 times greater than that of the heat process. These results indicate that the highly functional tienchi seng extracts created through the ultrasonic thermal fusion process are more industrially useful than those produced using the heat process.

The Comparison of Seasonal Ginsenoside Composition Contents in Korean Wild Simulated Ginseng (Panax ginseng) which were Cultivated in Different Areas and Various Ages

The ginsenoside content was compared with wild simulated ginseng (Panax ginseng) collected every season at 11 wild simulated ginseng plantations in Korea. As a result, the total saponin of 7 years old wild simulated ginseng showed the highest content of 4.5% in spring sampling wild simulated ginseng, 2.0% in summer sampling wild simulated ginseng, 1.2% in winter sampling wild simulated ginseng and 1.0% in autumn sampling wild simulated ginseng. And also, the total saponin of 10 years old wild simulated ginseng showed the highest content of 3.9% in spring sampling wild simulated ginseng, summer sampling wild simulated ginseng (1.8%), winter sampling wild simulated ginseng (1.6%) and autumn sampling wild simulated ginseng (0.6%). Therefore, the total saponin of spring sampling wild simulated ginseng was about 4.5 – 6.5 times higher than that of autumn sampling wild simulated ginseng regardless of cultivation period.

Clinical Characteristics and Incidence of Perianal Diseases in Patients With Ulcerative Colitis

PURPOSE: While perianal disease (PAD) is a characteristic of patients with Crohn disease, it has been overlooked in patients with ulcerative colitis (UC). Thus, our study aimed to analyze the incidence and the clinical features of PAD in patients with UC. METHODS: We reviewed the data on 944 patients with an initial diagnosis of UC from October 2003 to October 2015. PAD was categorized as hemorrhoids, anal fissures, abscesses, and fistulae after anoscopic examination by experienced proctologists. Data on patients’ demographics, incidence and types of PAD, medications, surgical therapies, and clinical course were analyzed. RESULTS: The median follow-up period was 58 months (range, 12–142 months). Of the 944 UC patients, the cumulative incidence rates of PAD were 8.1% and 16.0% at 5 and 10 years, respectively. The incidence rates of bleeding hemorrhoids, anal fissures, abscesses, and fistulae at 10 years were 6.7%, 5.3%, 2.6%, and 3.4%, respectively. The cumulative incidence rates of perianal sepsis (abscess or fistula) were 2.2% and 4.5% at 5 and 10 years, respectively. In the multivariate analyses, male sex (risk ratio [RR], 4.6; 95% confidence interval [CI], 1.7–12.5) and extensive disease (RR, 4.2; 95% CI, 1.6–10.9) were significantly associated with the development of perianal sepsis. CONCLUSION: Although the clinical course of PAD in patients with UC is not serious, in clinical practice, PAD is not rare in such patients. Therefore, careful examination and appropriate management for PAD is needed if the quality of life for patients with UC is to be improved.

Comparison of partially-absorbable lightweight mesh with heavyweight mesh for inguinal hernia repair: multicenter randomized study

PURPOSE: Prosthetic mesh is widely used for inguinal hernia repair; however, pain and stiffness can develop. This study was a prospective, multicenter, single-blind, randomized trial to assess postoperative pain and quality of life according to mesh type after inguinal hernia repair. METHODS: Forty-seven patients who underwent Lichtenstein repair for unilateral inguinal hernia with prosthetic mesh were enrolled and randomly allocated to the partially-absorbable lightweight mesh (LW group, n = 24) or heavyweight mesh group (HW group, n = 23). Data were collected using a visual analogue scale (VAS), Carolinas Comfort Scale (CCS), and Activities Assessment Scale (AAS) at screening and postoperative day 1, 7, 90, and 120; foreign body sensation, sense of stiffness, and sense of pull during activity were also evaluated. RESULTS: There were no significant differences in patients' demographics and clinical characteristics between groups. The VAS at day 90 was significantly lower in the LW group (0.46 ± 0.78 vs. 0.96 ± 0.82, P = 0.027). The CCS and AAS were significantly lower in the LW group at day 1 (51.33 ± 20.29 vs. 64.65 ± 22.64, P = 0.047 and 39.83 ± 9.88 vs. 46.43 ± 7.82, P = 0.015, respectively). Foreign body sensation was significantly lower in the LW group at day 120 (4.2% vs. 30.4 %, P = 0.023), as was sense of stiffness (P = 0.023). The sense of pull during activity was lower in the LW group at day 90 and 120 (P = 0.012 and P = 0.022, respectively). There was no recurrence or serious complication during follow-up. CONCLUSION: Partially-absorbable lightweight prosthetic mesh can be used for inguinal hernia repair safely and improve functional outcomes and quality of life after surgery.

Comparison of partially-absorbable lightweight mesh with heavyweight mesh for inguinal hernia repair: multicenter randomized study

PURPOSE: Prosthetic mesh is widely used for inguinal hernia repair; however, pain and stiffness can develop. This study was a prospective, multicenter, single-blind, randomized trial to assess postoperative pain and quality of life according to mesh type after inguinal hernia repair. METHODS: Forty-seven patients who underwent Lichtenstein repair for unilateral inguinal hernia with prosthetic mesh were enrolled and randomly allocated to the partially-absorbable lightweight mesh (LW group, n = 24) or heavyweight mesh group (HW group, n = 23). Data were collected using a visual analogue scale (VAS), Carolinas Comfort Scale (CCS), and Activities Assessment Scale (AAS) at screening and postoperative day 1, 7, 90, and 120; foreign body sensation, sense of stiffness, and sense of pull during activity were also evaluated. RESULTS: There were no significant differences in patients' demographics and clinical characteristics between groups. The VAS at day 90 was significantly lower in the LW group (0.46 ± 0.78 vs. 0.96 ± 0.82, P = 0.027). The CCS and AAS were significantly lower in the LW group at day 1 (51.33 ± 20.29 vs. 64.65 ± 22.64, P = 0.047 and 39.83 ± 9.88 vs. 46.43 ± 7.82, P = 0.015, respectively). Foreign body sensation was significantly lower in the LW group at day 120 (4.2% vs. 30.4 %, P = 0.023), as was sense of stiffness (P = 0.023). The sense of pull during activity was lower in the LW group at day 90 and 120 (P = 0.012 and P = 0.022, respectively). There was no recurrence or serious complication during follow-up. CONCLUSION: Partially-absorbable lightweight prosthetic mesh can be used for inguinal hernia repair safely and improve functional outcomes and quality of life after surgery.

Persistent Bleeding Following a Stapled Hemorrhoidopexy

A stapled hemorrhoidopexy (SH) is widely used for treatment of patients with grades III and IV hemorrhoids. The SH is easy to perform, is associated with less pain and allows early return to normal activities. However, complications, whether severe or not, have been reported. Here, we present the case of a female patient with persistent bleeding after a SH. The bleeding was caused by the formation of granulation tissue at the stapler line, diagnosed with sigmoidoscopy, and successfully treated via transanal excision (TAE) under spinal anesthesia. The biopsy showed inflammatory granulation tissue. After the TAE, her symptom was completely gone.

The Clinical Features and Predictive Risk Factors for Reoperation in Patients With Perianal Crohn Diseases; A Multi-Center Study of a Korean Inflammatory Bowel Disease Study Group

PURPOSE: Perianal lesions are common in Crohn disease, but their clinical course is unpredictable. Nevertheless, predicting the clinical course after surgery for perianal Crohn disease (PCD) is important because repeated operations may decrease patient's quality of life. The aim of this study was to predict the risk of reoperation in patients with PCD. METHODS: From September 1994 to February 2010, 377 patients with PCD were recruited in twelve major tertiary university-affiliated hospitals and two specialized colorectal hospitals in Korea. Data on the patient's demographics, clinical features, and surgical outcomes were analyzed. RESULTS: Among 377 patients, 227 patients were ultimately included in the study. Among the 227 patients, 64 patients underwent at least one reoperation. The median period of reoperation following the first perianal surgery was 94 months. Overall 3-year, 5-year, and 10-year cumulative rates of reoperation-free individuals were 68.8%, 61.2%, and 50.5%, respectively. In multivariate analysis (Cox-regression hazard model), reoperation was significantly correlated with an age of onset less than 20 years (hazard ratio [HR], 1.93; 95% confidence interval [CI], 1.07-3.48; P = 0.03), history of abdominal surgery (HR, 1.99; 95% CI, 1.08-3.64; P = 0.03), and the type of surgery. Among types of surgery, fistulotomy or fistulectomy was associated with a decreased incidence of reoperation in comparison with incision and drainage (HR, 0.19; 95% CI, 0.09-0.42; P < 0.001). CONCLUSION: Young age of onset and a history of abdominal surgery were associated with a high risk of reoperation for PCD, and the risk of reoperation were relatively low in fistulotomy or fistulectomy procedures.

Comparison of Preoperative and Postoperative Ocular Biometry in Eyes with Phakic Intraocular Lens Implantations

PURPOSE: To compare preoperative and postoperative ocular biometry in patients with iris-fixated phakic intraocular lens (pIOLs): Artisan and Artiflex. MATERIALS AND METHODS: This study included 40 eyes with Artisan and 36 eyes with Artiflex pIOL implants. Anterior chamber depth (ACD) and axial length (AL) were measured by applanation ultrasonography (A-scan) and partial coherence interferometry (IOLMaster) preoperatively and 3 months after pIOL implantation. RESULTS: ACD measurements after Artisan or Artiflex pIOL implantation were smaller than preoperative measurements. Specifically, the difference after Artisan pIOL implantation was -1.07+/-0.17 mm by A-scan and -0.08+/-0.08 mm by IOLMaster. The difference after Artiflex pIOL implantation was -1.31+/-0.15 mm by A-scan and -0.05+/-0.07 mm by IOLMaster. After Artisan pIOL implantation, differences in AL measurements by A-scan were insignificant (difference: -0.03+/-0.15 mm), whereas postoperative AL measurements by IOLMaster were significantly longer than preoperative measurements (difference: 0.12+/-0.07 mm). After Artiflex pIOL implantation, AL measurements by both A-scan and IOLMaster were significantly longer than preoperative measurements (difference: 0.09+/-0.16 mm by A-scan and 0.07+/-0.10 mm by IOLMaster). In the Artiflex group, differences in AL measurements by A-scan correlated with the central thickness of the Artiflex pIOL. CONCLUSION: ACD and AL measurements were influenced by iris-fixated phakic IOL implantation.

Spontaneously Healed Membranous Type Ventricular Septal Defect with Malaligned Interventricular Septal Wall and Double-Chambered Right Ventricle in a 56-Year-Old Patient

A 56-year-old male presented with resting dyspnea and chest discomfort for several years. During transthoracic and transesophageal echocardiography, a spontaneously healed membranous type ventricular septal defect (VSD) with malaligned interventricular septal wall, aneurysmal changes, a subaortic ridge and a double-chambered right ventricle (DCRV) was observed. When combined with DCRV, VSD with malalignment between the outlet and trabecular septa was associated with tetralogy of Fallot. The subaortic ridge was due to turbulent flow caused by the malalignment-type VSD. The VSD with malaligned interventricular septal wall can be developed after aneurismal changes of a perimembranous VSD. We report here in the unusual case of a 56-year-old patient who had a pathology complex comprising DCRV, subaortic ridge, spontaneously healed membranous type VSD with malaligned interventricular septal wall, and survived with surgical treatment.

Endoscopic Submucosal Dissection for Colorectal Neoplasia: Early Outcomes After 260 Cases

PURPOSE: Endoscopic submucosal dissection (ESD), a recently introduced endoscopic technique, makes it possible to perform an en-bloc resection of a lesion regardless of its size. The aim of this study was to report early experiences with colorectal ESD performed in our hospital. METHODS: Between October 2006 and December 2008, we performed an ESD for 260 consecutive cases of colorectal neoplasia in 255 patients. We evaluated the clinical outcomes, except for two failure cases of bowel perforation. RESULTS: The mean resected tumor size was 24.2+/-9.8 (5-60) mm. Our overall endoscopic en-bloc resection rate was 93.0% (240/258). and the pathologically margin free rate was 91.5% (236/258). Perforation occurred in 7.7% (20/260) of the cases. In 17 patients, perforation was managed by endoscopic clipping without salvage surgery; the other three patients underwent a laparoscopic operation. Pathological examination showed an adenocarcinoma in 35.4% of the cases (92/260). We recommended additional radical surgery in 13 cases (submucosal invasion less than 1 mm with unfavorable pathology: 1 case; unknown depth of submucosal invasion: 1 case; submucosal invasion > or =1 mm: 9 cases; invasion to proper muscle: 2 cases). We were able to check the recurrence rate through colonoscopy for 125 patients. During the mean follow-up period of 8.0+/-4.3 (3-21) mo, there were no recurrences. CONCLUSION: ESD was technically difficult, had a substantial risk of perforation, and needed a long procedure time. However, ESD enabled en-bloc resection of large colorectal tumors. As experience with the technique increases, ESD might gradually replace piecemeal endoscopic mucosal resection (EMR) and radical colon resection in the treatment of colorectal tumors.

Early Experience with a Stapled TransAnal Rectal Resection for Obstructed Defecation Syndrome

PURPOSE: This study was designed to assess the early outcome of a stapled transanal rectal resection (STARR) in obstructed defecation syndrome (ODS) patients with rectocele and rectal intussusception. METHODS: From January to December in 2005, 41 patients with the symptoms of obstructed defecation and the findings of rectocele and rectal intussusception in defecography, who failed in conservative management, were enrolled in this study. All patients underwent the STARR procedure. Preoperatively all patients received colonoscopy, a colon transit time test, cinedefecography, etc. The constipation score was evaluated by using the Cleveland Clinic Florida (CCF) constipation score preoperatively and at 1 month and 3 months after operation. RESULTS: The mean age of the patients was 55.3 (19~76) years. There were three males and thirty-eight females. The mean operation time was 39.3 (25~80) minutes, and the mean hospital stay was 4.2 (4~6) days. Complications were fecal urgency in 9 cases (21.9%), which improved after 3 months, bleeding in 5 cases (12.2%), and anastomotic stenosis in 1 case (2.4%). At postoperative defecography, both intussusception and rectocele had disappeared in most patients. All constipation symptoms were significantly improved (P < 0.01). The mean CCF constipation score was 17.6 (11~24) preoperatively, and improved to 9.1 after 1 month and 8.2 after 3 months (P < 0.01). The overall patient satisfaction was graded as excellent, good, fairly good and poor in 19 cases (46.3%), 13 cases (31.7%), 4 cases (9.7%), and 5 cases (12.2%), respectively. CONCLUSION: The STARR procedure seems to be a safe and effective procedure in ODS patients with rectocele and rectal intussusception. However, further study of the long-term results is required.

Clinical Outcomes of Lateral Internal Sphincterotomy for Patients with Chronic Anal Fissure

PURPOSE: A lateral internal sphincterotomy (LIS) is a safe and effective surgical treatment that is the most commonly used one for patients with chronic anal fissure. However, reports on the recurrence rate and complications after LIS published in Korea are rare. The purpose of our study is to identify the types and rates of recurrence, the complications after LIS, and the differences in clinical outcomes between open and closed LIS. RESULTS: We used hospital records and telephone interviews to study retrospectively the rates of recurrence and complications of 898 patients who underwent a LIS for chronic anal fissure from July, 2003, to June 30, 2004. RESULTS: There were 292 male (mean age: 36.8 years, range: 16~84) and 606 female (mean age: 32.4 years, range: 1~68) patients. The preoperative mean maximum resting pressure in anal manommetry was 99.2 cmH2O in male patients and 97.7 cmH2O in female patients. Recurrence of fissure after LIS was present in five cases (0.6%). All underwent a LIS, on the same side of a previous LIS in four cases and on the opposite side in one case. Delayed healing of the fissure was present in six cases (0.7%). All of these patients were improved by conservative management. Complications of the LIS were thrombus formation, perianal abscess, fistula, and incontinence. Thrombus formation was present in eight cases (0.9%). Five patients underwent a thrombectomy and three patients were cured by conservative management. Perianal abscess or fistula was present in three patients (0.3%), who underwent incision and drainage or a simple fistulotomy. Incontinence was present in two cases (0.2%). One patient was lost to follow up, and the other patient was improved by conservative management. CONCLUSIONS: LIS is a safe and effective treatment for patients with chronic anal fissure, and recurrence and complications of LIS are rare.

Clinical usefulness of facial soft tissues thickness measurement using 3D computed tomographic images / 대한구강악안면방사선학회지

PURPOSE: To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. MATERIALS AND METHODS: One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. RESULTS: There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7mm slice thickness. CONCLUSION: The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

Measurement of facial soft tissues thickness using 3D computed tomographic images / 대한구강악안면방사선학회지

PURPOSE: To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. MATERIALS AND METHODS: One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side, The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. RESULTS: There were no statistically significant differences between the direct measurements and those using the 3D images (p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. CONCLUSION: The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissues thickness more easily in forensic science and anthropology.

Computer-assisted Evaluation of Pedicle Screw Position on CT Images / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to develop a personal computer-based method to facilitate the evaluation of pedicle screw position on computed tomography (CT) scan images and to assess its diagnostic value. MATERIAL AND METHOD: A personal computer-based method was developed using the CT images of 17 patients having a total of 84 pedicle screws. Images with a window range of -2, 000 to +3, 000 were inverted; a multiplanar reconstruction viewer was then produced to create these images in the sagittal and coronal planes. Finally, lines circumscribing the threaded portion of screws were drawn on the images. For CT images of thirty-two pedicle screws placed in the lumbar vertebrae of four pigs, screw locations were evaluated by 6 orthopaedic surgeons by our method and by conventional bone window setting. The diagnostic values of the two methods were calculated and compared. RESULT: Our method significantly improved the specificity (from 82% to 94%, p=0.007), the positive predictive value (from 79% to 92%, p=0.015), and inter-observer agreement (from 0.61 to 0.78, p<0.001) in terms of identifying misplaced screws. CONCLUSION: The described method improves the diagnostic accuracy and inter-observer reliability for the identification of misplaced pedicle screws on CT scan images.

Studies of Laser Subepithelial Keratomileusis (LASEK) using Leghorn Chick Eye

PURPOSE: Using the effect of 20% ethanol on Leghorn chick cornea, a suitable animal model for LASEK(Laser subepithelial keratomileusis) and effect on LASEK were evaluated. METHODS: Twenty Chick corneas were divided into 4 groups (n=5/group) to be exposed to 20% ethanol for 30 sec, 45 sec, 1 minute and 2 minutes respectively and changes were observed. Another 4 groups of Chick cornea, total of 20 (n=5/group) were prepared to perform nothing, PRK after mechanical or 20% ethanol-assisted debridement, or LASEK respectively and corneal changes were observed. RESULTS: Exposure of the corneal epithelium to 20% ethanol for more than 30 seconds allowed reproducible separation of epithelial flaps in Leghorn chick eyes. TUNEL staining of corneas obtained 4 hours after surgery revealed TUNEL-positive cells in the central superficial stroma and more abundantly in the peripheral superficial stroma around the epithelial flap margin and in the epithelial flap itself, particularly in the basal epithelial layer. Transmission electron microscopy showed similar evidence of apoptosis in the epithelium and anterior stroma. CONCLUSIONS: The Leghorn chick eye appears to be a reasonable model for LASEK surgery. Treatment with 20% ethanol for 30 seconds results in reproducible epithelial flap creation in the chick cornea and in relatively low levels of stromal and epithelial cell death after surgery.

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.

The Change of Eyeball Contour and Factors Affecting Corneal Flap using Automated Microkeratome in LASIK

PURPOSE: To evaluated the effect of suction ring on eyeball contour and its influence on the corneal flap made in LASIK(laser in situ keratomileusis). METHODS: We measured corneal thickness and axial length of 47 eyes, before and during application of the suction ring, in those which had undergone LASIK. The diameter and thickness of corneal flap made with Automated Corneal Shaper(R) were also measured in operation room. RESULTS: When applying suction ring while making a corneal flap, corneal thickness and axial length were decreased significantly(p<0.05), and the diameter of the flap was decreased as preoperative corneal curvature decreased(p<0.05). CONCLUSIONS: Careful attention is needed not to give an eyeball unnecessary pressure which may result in intraocular damage or flap complications such as free cap especially when their corneal curvature is too flat.