• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.311-316
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• 2007

Objective : The objective of this study is to investigate the safety, surgical efficacy, and advantages of a polyaxial screw-rod system for posterior occipitocervicothoracic arthrodesis. Methods : Charts and radiographs of 32 patients who underwent posterior cervical fixation between October 2004 and February 2006 were retrospectively reviewed. Posterior cervical polyaxial screw-rod fixation was applied on the cervical spine and/or upper thoracic spine. The surgical indication was fracture or dislocation in 18, C1-2 ligamentous injury with trauma in 5, atlantoaxial instability by rheumatoid arthritis (RA) or diffuse idiopathic skeletal hyperostosis (DISH) in 4, cervical spondylosis with myelopathy in 4, and spinal metastatic tumor in 1. The patients were followed up and evaluated based on their clinical status and radiographs at 1, 3, 6 months and 1 year after surgery. Results : A total of 189 screws were implanted in 32 patients. Fixation was carried out over an average of 3.3 spinal segment (range, 2 to 7). The mean follow-up interval was 20.2 months. This system allowed for screw placement in the occiput, C1 lateral mass, C2 pars, C3-7 lateral masses, as well as the lower cervical and upper thoracic pedicles. Satisfactory bony fusion and reduction were achieved and confirmed in postoperative flexion-extension lateral radiographs and computed tomography (CT) scans in all cases. Revision surgery was required in two cases due to deep wound infection. One case needed a skin graft due to necrotic change. There was one case of kyphotic change due to adjacent segmental degeneration. There were no other complications, such as cord or vertebral artery injury, cerebrospinal fluid leak, screw malposition or back-out, or implant failure, and there were no cases of postoperative radiculopathy due to foraminal stenosis. Conclusion : Posterior cervical stabilization with a polyaxial screw-rod system is a safe and reliable technique that appears to offer several advantages over existing methods. Further biomechanical testings and clinical experiences are needed in order to determine the true benefits of this procedure.

• Journal of Korean Neurosurgical Society
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• v.53 no.1
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• pp.49-51
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• 2013

A case of traumatic spondyloptosis of the cervical spine at the C6-C7 level is reported. The patient was treated succesfully with a anterior-posterior combined approach and decompression. The patient had good neurological outcome after surgery. A-51-year-old female patient was transported to our hospital's emergency department after a vehicle accident. The patient was quadriparetic (Asia D, MRC power 4/5) with severe neck pain. Plain radiographs, computerize tomography and spinal magnetic resonance imaging (MRI) showed C6-7 spondyloptosis and C5, C6 posterior element fractures. Gardner-Wells skeleton traction was applied. Spinal alignment was reachived by traction and dislocation was decreased to a grade 1 spondylolisthesis. Then the patient was firstly operated by anterior approach. Anterior stabilization and fusion was firstly achieved. Seven days after first operation the patient was operated by a posterior approach. The posterior stabilization and fusion was achieved. Postoperative lateral X-rays and three-dimensional computed tomography showed the physiological realignment and the correct screw placements. The patient's quadriparesis was improved significantly. Subaxial cervical spondyloptosis is a relatively rare clinical entity. In this report we present a summary of the clinical presentation, the surgical technique and outcome of this rarely seen spinal disorder.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.20.2-20.2
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• 2011

III-nitrides have attracted much attention for optoelectronic device applications whose emission wavelengths ranging from green to ultraviolet due to their wide band gap. However, due to the strong polarization properties of conventional c-plane III-nitrides, the built-in polarization-induced electric field limits the performance of optical devices. Therefore, there has been a renewed interest in the growth of nonpolar III-nitride semiconductors for polarization free heterostructure optoelectronic and electronic devices. However, the crystal and the optical quality of nonpolar/semipolar GaN have been poorer than those of conventional c-plane GaN, resulting in the relative poor optical and electrical properties of light emitting diodes (LEDs). In this presentation, I will discuss the growth and characterization of high quality nonpolar a-plane and semipolar (11-22) GaN and InGaN multiple quantum wells (MQWs) grown on r- and m-plane sapphire substrates, respectively, by using metalorganic chemical vapor deposition (MOCVD) without a low temperature GaN buffer layer. Especially, the epitaxial lateral overgrowth (ELO) technique will be also discussed to reduce the dislocation density and enhance the performance of nonpolar and semipolar GaN-based LEDs.

• Journal of Korean Physical Therapy Science
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• v.5 no.4
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• pp.717-728
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• 1998

The Temporomandibural joint(TMJ) is one of the most frequently used joint in the body as $1,500{\sim}2,000$ times per day for the activities of chewing, swallowing, talking, yawing and sneezing. The TMJ are formed by condylar process of mandible and mandible fossa of temporal bone, separated by an articular disc. This articular disc divides into two cavities as upper cavity and lower cavity. The gliding movement occurs in the upper cavity of the joint, whereas hinge movement occurs in the lower cavity. The movements that are allowed at the TMJ are opening, closing, protrusion, retraction and lateral movement. A cause of TMJ dysfunction are capsulitis, internal derangement, osteoarthritis, rheumatoid arthritis, infection and inflammation near the joint, trauma on joint, ankylosis, subluxation or dislocation of joint, injury of articular disc, myositis, muscle contracture or spasm, myofascial pain dysfunction syndrome, dyskinesia of masticatory muscles, developmental abnormality, tumor, connective tissue disease, fibrosis, malocclusion, swallowing abnormality, wrong habits such as bite nail or hair, bruxism, psycological stress and Costen syndrome etc. Assessment of TMJ dysfunction consist of interview, observation, functional examination, palpation, reflex test, joint play test, electromyography and radiologic examination and behavioral and psycological assessment etc.

• Journal of radiological science and technology
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• v.28 no.3
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• pp.203-209
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• 2005

Objective True lateral scapular image was very important to diagnosis the scapular fracture and dislocation induced by traumatic injury. The aim of this study was to know the patient rotation angle to be showing the scapular true lateral in Korean. Subjects and Materials Thirty patients(22men, 8 women, mean ages 53.4)with scapular pain, had supine anteroposterior projection taken with $32^{\circ}$, $37^{\circ}$, $42^{\circ}$ trunk rotation angle changing the manual angulation material. Radiographs were evaluated independently by 5 experienced observers(1 orthopedics surgery specialist, 1 diagnostic radiology specialist, 3 radiological technologist) They assessed overlab of vertebral border and axillary border of scapular as follows; Totally overlapping of vertebral border and axillary border is 4, partially overlapping is 3, not overlapping is 2 and oblique location with two borders is 1. All observers scored using by PACS monitor. Results $32^{\circ}$ trunk rotation was scored $1.53{\pm}0.39$, $37^{\circ}$ trunk rotation was scored $3.83{\pm}0.15$ and $42^{\circ}$trunk rotation was scored $2.17{\pm}0.43$. There was no difference(p<0.05) between group of more than 100cm of the girth of the chest and group of less than 100cm. Similarly, men and women group showed no difference(p<0.05) with trunk rotation statistically. Conclusions There was no result of trunk rotation angle to radiograph the true scapular lateral image up to date. This studies were summarized as follows; Adaptation of $37^{\circ}$ trunk rotation was the best to show the true scapular lateral image in Korean. Our results were very useful to get the true scapular lateral images in clinic.

• Clinics in Shoulder and Elbow
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• v.9 no.1
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• pp.50-59
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• 2006

Purpose: The nonoperative outcome of elbow dislocations with associated radial head and coronoid fractures are often unsatisfactory because of chronic instability and stiffness from proloned immobilization, Therefore we managed these injuries with well programed surgical appproaches. Method: Ten patients with this injury were evaluated retrospectively from May 1998 to June 2004 after a minimum of 12 months. These injuries include elbow dislocation and associated fractures of both the radial head and the coronoid process. All ten patients were treated by one clinic operatively with similar scheduled surgical methods which started on the lateral side and terminated on the medial side of the elbow. Radial head and neck fractures were classified Mason types, as two and three types respectively with six and four cases and six cases were fixated. Coronoid process were fixated with screws anteroposterior directly or anchor suture in all cases, each type was classified one, two and three. where were three type one, four type two, and three type three were according to Regan and Morrey classification. Results: The outcome was three resulting in excellent, four good, two normaland and the remaining case was one poor according to the Mayo Elbow Performance score. At a terminal follow up, the range of motion of the elbow averaged flection contracture, $6^{\circ}(0{\sim}20^{\circ})$ and further flection, $129^{\circ}(115{\sim}140^{\circ})$. Two patients had complications requiring additional care. One, displaced coronoid process which was repaired with capsule and the other patient experienced, palsy of ulnar nerve and contracted elbow joint. Conclusions: Usage of early operation as the minimum injury of medial ligaments complex and the rigid fixation of fractures to prompt motion with our scheduled management for elbow dislocations with associated radial head and coracoid fractures provided excellent results.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.156-161
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• 2009

Purpose: The fracture of talus has critical complications and results in various clinical outcomes. The purpose of this study is to evaluate clinical outcome and influence on involvement of ankle and subtalar joint. Materials and Methods: From December 1999 to December 2008, a total of 66 fractures and dislocations of talus was treated with minimal 9 months follow up period. Ankle-hindfoot scale of the American Orthopedic Foot & Ankle Society (AOFAS) was used to evaluate the clinical outcome. The complications and sequential radiologic findings were also analyzed. Results: There were 28 neck fractures, 11 lateral process fractures, 10 body fractures, 7 osteochondral fractures, 4 posteromedial tubercle fractures and 4 medial process fractures. In 38 cases, there were concomitant injuries. Ipsilateral ankle fracture, which found in 19 cases, was most common. The surgical treatment was performed in 36 cases. Mean AOFAS score was 85.5 (range, 72 to 96). In 13 of 47 cases, one or more fracture lines involving weight bearing surface were confirmed. The involvement of ankle or subtalar joint had resulted in unsatisfied outcome. Complications were developed as follows, post-traumatic arthritis in 8 cases, avascular necrosis in 3 cases, and deep infection in 2 cases. Conclusion: The involvement of ankle or subtalar joint in fractures of talus seemed to be common and to impact the clinical outcome. Meticulous consideration about that will be positively necessary.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.11
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• pp.702-706
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• 2016

We demonstrated that self-separation FS-GaN (freestanding-GaN) was grown on MELO (maskless epitaxially lateral overgrowth) GaN template by horizontal HVPE (hydride vapor phase epitaxy). Before thick GaN grwoth, MELO GaN template was grown on patterned GaN template by MOCVD (metal organic chemical vapor deposition). The laterally overgrown GaN would consist of a continuous well coalesced layer. The mixed TDD (threading dislocation density) of seed and wing region were $8{\times}10^8cm^{-2}$ and $7{\times}10^7cm^{-2}$, respectively. After thick GaN grown by HVPE, the self-separation between thick GaN and sapphire substrate was generated at seed region. The regions of self-separation for FS-GaN and sapphire were observed by FE-SEM. Moreover, Raman results indicated that the compressive strain of seed and wing regions at FS-GaN substrate were slightly released compared to that of thick GaN grown on conventional GaN template. The optical properties of the FS-GaN substrate were examined by using PL (photoluminescence). The PL exhibited that donor bound exciton and donor acceptor pair were observed at low temperature. The effects on optical and structural properties of FS-GaN substrate have been discussed in detail.

• Parasites, Hosts and Diseases
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• v.31 no.1
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• pp.7-12
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• 1993

Metaceriae of Parvatrema timondavidi (Digenea; Grmnophallidae) were found from Tapes phillippinarum, one of the most common marine clams in Korean. T. were philippinarum was collected from a fishery market in seoul, and all of the clams eximined were found to contain many gymnophyallid metacercariae. To get adult worms, 10 ICR mice were fed with 100 metacercariae each and sacrificed by cervical dislocation at 7, 10 and 14 mice were morphologically characterized by oval body shape, lage oral sucker with lateral located genital pore from the venttral sucker. Based on these characters they identified as P.timondawvidi Bartoli, 1964. this study first confirms the presence of P. timondawcidi metacercartae in T.philippinarum in Korea.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.148-149
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• 2012

This paper reports doping of carbon atoms in GaN layer, which based on dimethylhydrazine (DMHy) and growth temperature. It is well known that dislocations can act as non-radiative recombination center in light emitting diode (LED). Recently, many researchers have tried to reduce the dislocation density by using various techniques such as lateral epitaxial overgrowth (LEO) [1] and patterned sapphire substrate (PSS) [2], and etc. However, LEO and PSS techniques require additional complicated steps to make masks or patterns on the substrate. Some reports also showed insertion of carbon doped layer may have good effect on crystal quality of GaN layer [3]. Here we report the growth of GaN epitaxial layer by inserting carbon doped GaN layer into GaN epitaxial layer. GaN:C layer growth was performed in metal-organic chemical vapor deposition (MOCVD) reactor, and DMHy was used as a carbon doping source. We elucidated the role of DMHy in various GaN:C growth temperature. When growth temperature of GaN decreases, the concentration of carbon increases. Hence, we also checked the carbon concentration with DMHy depending on growth temperature. Carbon concentration of conventional GaN is $1.15{\times}1016$. Carbon concentration can be achieved up to $4.68{\times}1,018$. GaN epilayer quality measured by XRD rocking curve get better with GaN:C layer insertion. FWHM of (002) was decreased from 245 arcsec to 234 arcsec and FWHM of (102) decreased from 338 arcsec to 302 arcsec. By comparing the quality of GaN:C layer inserted GaN with conventional GaN, we confirmed that GaN:C interlayer can block dislocations.