• Journal of Korean Neurosurgical Society
• /
• v.53 no.1
• /
• pp.6-12
• /
• 2013

Objective : This consecutive retrospective study was designed to analyze and to compare the efficacy and outcomes of anterior cervical discectomy and fusion (ACDF) using a fibular and femur allograft with anterior cervical plating. Methods : A total of 88 consecutive patients suffering from cervical degenerative disc disease (DDD) who were treated with ACDF from September 2007 to August 2010 were enrolled in this study. Thirty-seven patients (58 segments) underwent anterior interbody fusion with a femur allograft, and 51 patients (64 segments) were treated with a fibular allograft. The mean follow-up period was 16.0 (range, 12-25) months in the femur group and 19.5 (range, 14-39) months in the fibular group. Cage fracture and breakage, subsidence rate, fusion rate, segmental angle and height and disc height were assessed by using radiography. Clinical outcomes were assessed using a visual analog scale and neck disability index. Results : At 12 months postoperatively, cage fracture and breakage had occurred in 3.4% (2/58) and 7.4% (4/58) of the patients in the femur group, respectively, and 21.9% (14/64) and 31.3% (20/64) of the patients in the fibular group, respectively (p<0.05). Subsidence was noted in 43.1% (25/58) of the femur group and in 50.5% (32/64) of the fibular group. No difference in improvements in the clinical outcome between the two groups was observed. Conclusion : The femur allograft showed good results in subsidence and radiologic parameters, and sustained the original cage shape more effectively than the fibular allograft. The present study suggests that the femur allograft may be a good choice as a fusion substitute for the treatment of cervical DDD.

• Journal of the Korean Orthopaedic Association
• /
• v.54 no.3
• /
• pp.203-210
• /
• 2019

The aim of this review was to evaluate minimally invasive lateral lumbar interbody fusion on the latest update. Lumbar interbody fusion was introduced recently. This study performed, a literature review of the indications, clinical outcomes, fusion rate, and complications regarding recently highlighted minimally invasive lateral lumbar interbody fusion. The indications of lateral lumbar interbody fusion are similar to the conventional anterior and posterior interbody fusion in degenerative lumbar diseases. In particular, lateral lumbar interbody fusion is an effective minimally invasive surgery in spinal stenosis, degenerative spondylolisthesis, degenerative adult deformity, degenerative disc disease and adjacent segment disease. In addition, the clinical outcomes and fusion rates of lateral lumbar interbody fusion are similar compared to conventional lumbar fusion. On the other hand, non-specific complications including hip flexor weakness, nerve injury, vascular injury, visceral injury, cage subsidence and pseudohernia have been reported. Lateral lumbar interbody fusion is a very useful minimally invasive surgery because it has advantages over conventional anterior and posterior interbody fusion without many of the disadvantages. Nevertheless, nonspecific complications during lateral lumbar interbody fusion procedure remain a challenge to be improved.

• Journal of Korean Foot and Ankle Society
• /
• v.8 no.2
• /
• pp.171-175
• /
• 2004

Purpose: We evaluated the clinical and radiological results of arthroscopic ankle fusion using 2 medial screws which had advantages of less morbidity, early weight-bearing and high union rate. Material and Methods: From April, 2002 to March, 2004, 8 patients who had ankle osteoarthritis were treated by ankle fusion using 2 medial screws under arthroscopy; five patients with post-traumatic osteoarthritis, two with post-infectious arthritis and one with paralytic foot. There were 5 male and 3 female. Average age was 67 years old ranging from 57 to 71 years. We evaluated them clinically preoperative and postoperative using AOFAS score, VAS pain scale and patient's satisfaction. In regard to radiological fusion, we checked them by simple AP, lateral and mortise view. Follow up period was average 11 months (range, $6{\sim}24$ months). Results: All ankles were successfully fused with 2 medial screws under arthroscopy. The mean time of fusion was 10.5 weeks (range, $8{\sim}14$ weeks). Patient's satisfaction checked at 6 months after operation had favorable results (excellent and good 75%). One case had pain on medial malleolar area because of screw's protrusion. Conclusion: Arthroscopic ankle fusion using 2 medial screws was good modality of ankle fusion with less morbidity and early weight-bearing in some cases of ankle arthritis.

• Progress in Superconductivity and Cryogenics
• /
• v.14 no.2
• /
• pp.24-27
• /
• 2012

The superconducting coil system is one of the most important components in Korea Superconducting Tokamak Advanced Research (KSTAR), which has been operated since 2008. $Nb_3Sn$ and NbTi superconductors are being used for cable-in-conduit conductors (CICCs) of the KSTAR toroidal field (TF) and poloidal field (PF) coils. The CICCs are cooled by forced-flow supercritical helium about 4.5 K. The temperature, pressure and mass flow rate of the supercritical helium in the CICCs are interacting with each other during the operation of the coils. The complicate behaviors of the supercritical helium have an effect on the operation and the efficiency of the helium refrigeration system (HRS) by means of, for instance, pressure drop. The hydraulic characteristics of the supercritical helium have been monitored while the TF coils have stably achieved the full current of 35 kA. In other hands, the PF coils have been operated with various pulsed or bipolar mode, so the drastic changes happen in view of hydraulics. The heat load including AC loss on the coils has been analyzed according to the measurement. These activities are important to estimate the temperature margin in various PF operation conditions. In this paper, the latest hydraulic behaviors of PF coils during KSTAR operation are presented.

• Journal of Welding and Joining
• /
• v.31 no.1
• /
• pp.58-64
• /
• 2013

The following results were obtained, microstructures and tensile properties in arc brazed joints of DP(dual phase) steel using Cu-5.3wt%Sn insert metal was investigated as function of brazing current. 1) The Fusion Zone was composed of ${\alpha}Fe+{\gamma}Cu$ and Cu23Sn2. The reason for the formation of these solid solutions. Despite, Fe & Cu were impossible to solid solution at room temperature. It's melting & reaction to something of insert metal & Base Metal (DP Steel) by Arc. Brazing Process has faster cooling rate then Cast Process, Supersaturated solid solution at room temperature. 2) The increase Hardness of Fusion Zone was directly proportional to the rise of welding current. Because, ${\alpha}Fe+{\gamma}Cu$ phase (higher hardness than the Cu23Sn2.(104.1Hv < 271.9Hv)) Volume fraction was Growth, due to increasing the amount of base metal melting by High current. 3) The results of tensile shear test by Brazing, All specimens happen to fracture in Fusion Zone. On the other hand, when Brazing Current increasing tend to rise tensile load. but it was very small, about 26-30% of the base metal. 4) The result of fracture analysis, The crack initiate at Triple Point for meet to Upper B.M/Under B.M/Fusion Zone. This Crack propagated to Fusion zone. So ruptured by tensile strength. The Reason to in the fusion zone fracture, Fusion zone by Brazing of hardness (strength) was very lower then the base metal (DP steel). In addition the Fusion Zone's thickness in triple point was thin than the base metal's thickness in triple point.

• Journal of Pharmaceutical Investigation
• /
• v.41 no.3
• /
• pp.179-184
• /
• 2011

This study aimed to confirm the effect of molecular weight (MW) in solid dispersion of carvedilol with poly-vinylpyrrolidone (PVP) of various MW. Solid dispersion of carvedilol with PVP was prepared by spray-drying method. Scanning electron microscopy (SEM) was used to analyze the surface of solid dispersion samples. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to analyze the crystalline of solid dispersion. Fourier transform infrared spectroscopy (FT-IR) was used to analyze the change of chemical structure characteristic of solid dispersion. DSC and XRD show that drug crystalline was changed. FT-IR revealed that chemical structure of solid dispersion comparing the chemical structure of drug was changed. The dissolution studies of solid dispersion presented at simulated gastric juice (pH 1.2). The dissolution rate of solid dispersion was dramatically enhanced than pure drug and the MW of PVP has an effect on the release property of carvedilol in solid dispersion. In conclusion, the present study has confirmed the effect of MW of PVP on release property of solid dispersion formulation of carvedilol with PVP.

• Journal of Pharmaceutical Investigation
• /
• v.37 no.6
• /
• pp.339-347
• /
• 2007

SMEDDS is mixture of oils, surfactants, and cosurfactants, which are emulsified in aqueous media under conditions of gentle agitation and digestive motility that would be encountered in the gastro-intestinal(GI) tract. The main purpose of this work is to prepare self-microemulsifying drug delivery system(SMEDDS) for oral bioavailability enhancement of a poorly water soluble drug, atorvastatin calcium. Solubility of atorvastatin calcium was determined in various vehicles. Pseudo-ternary phase diagrams were constructed to identity the efficient self-emulsification region and particle size distributions of the resultant micro emulsions were determined using a laser diffraction sizer. Optimized formulations for in vitro dissolution and bioavailability assessment were $Capryol^{(R)}$ 90(50%), Tetraglycol(16%), and $Cremophor^{(R)}$ EL(32%). The release rate of atorvastatin from SMEDDS was significantly higher than the conventional tablet ($Lipitor^{(R)}$), 2-fold. Our studies illustrated the potential use of SMEDDS for the delivery of hydrophobic compounds, such as atorvastatin calcium by the oral route.

• Journal of Pharmaceutical Investigation
• /
• v.38 no.2
• /
• pp.119-126
• /
• 2008

Solid dispersions of poorly water-soluble drug, sibutramine, were prepared with hydrophilic polymer, poly-N-vinylpyrrolidone (PVP), hydroxypropylmethylcellulose (HPMC) and organic acid, citric acid, to improve the solubility of drug. Physicochemical variation and shape of microsphere were characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and Fourier-transform infrared spectroscopy (FT-IR). Microspheres containing additives showed more spherical shape than non additive microspheres. In vitro release behavior of microspheres presented at simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8). The solid dispersion form transformed the drug into an amorphous state and dramatically improved its dissolution rate. These data suggest that the solid dispersion technique is an effective approach for developing the appetite depressant drug products and various pharmaceutical excipients are able to control the release behaviors.

• Journal of Korean Neurosurgical Society
• /
• v.37 no.5
• /
• pp.340-344
• /
• 2005

Objective: Posterior lumbar interbody fusion(PLIF), the current leading method of pedicle screw fixation combined with interbody fusion via posterior route, sometimes requires too much destruction of the facet joint than expected especially for the patient with a narrow spine. On the other hand, tranforaminal lumbar interbody fusion(TLIF) technique provides potential advantages over PLIF and can be chosen as a better surgical alternative to more traditional fusion methods in certain surgical conditions. Methods: From October 1999, 99 PLIF and 29 TLIF procedures were done for the patients with spinal stenosis and instability. Radiological data including the interpedicular distance and the size of the pedicles as well as the clinical parameters were collected retrospectively. The degree of resection of the inferior articular process was compared with the interpedicular distance in each patient who received PLIF. Results: No significant differences were found between PLIF and TLIF regarding the operation time, blood loss, duration of hospital stay, or short term postoperative clinical result. There were no complication with TLIF, but PLIF resulted in 9(9.1%) complications. During PLIF procedure, all patients(n=24) except one with the interpedicular distance shorter than 27mm required near complete or complete resection of the inferior articular processes, whereas only 6(31.5%) of 19 patients with the interpedicular distances longer than 30mm required the similar extent of resection. Conclusion: TLIF is better than PLIF in terms of the complication rate. The patient who had narrow interpedicular distance(<27mm) might be better candidate for TLIF.

• Polymer(Korea)
• /
• v.33 no.6
• /
• pp.596-601
• /
• 2009

We prepared nanoparticles containing insoluble aceclofenac by the method of solid dispersions using spray dryer to improve solubility of aceclofenac. We used PVP-K30 as a water soluble carrier for the solid dispersion and poloxamer as a surfactant. Characterization of aceclofenac solid dispersion was performed by SEM, DSC, XRD and FT-IR. The results of SEM, DSC and XRD demonstrated that aceclofenac is amorphous in solid dispersion. The formation of salt by hydrogen bond between aceclofenac and PVP K-30 was confirmed by FT-IR. The dissolution rate measured in intestinal juice showed the method of solid dispersion improved aceclofenac solubility as compared with a conventional drug($Airtal^{(R)}$). In conclusion, the method of solid dispersion using spray dryer would improve solubility of aceclofenac in oral administration.