• Journal of Korean Neurosurgical Society
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• v.61 no.2
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• pp.277-281
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• 2018

Objective : Craniovertebral junctional anomalies constitute a technical challenge. Surgical opening of atlantoaxial joint region is a complex procedure especially in patients with nuchal deformity like basilar invagination. This region has actually very complicated anatomical and functional characteristics, including multiple joints providing extension, flexion, and wide rotation. In fact, it is also a bottleneck region where bones, neural structures, and blood vessels are located. Stabilization surgery regarding this region should consider the fact that the area exposes excessive and life-long stress due to complex movements and human posture. Therefore, all options should be considered for surgical stabilization, and they could be interchanged during the surgery, if required. Methods : A 53-year-old male patient applied to outpatients' clinic with complaints of head and neck pain persisting for a long time. Physical examination was normal except increased deep tendon reflexes. The patient was on long-term corticosteroid due to an allergic disease. Magnetic resonance imaging and computed tomography findings indicated basilar invagination and atlantoaxial dislocation.The patient underwent C0-C3-C4 (lateral mass) and additional C0-C2 (translaminar) stabilization surgery. Results : In routine practice, the sites where rods are bound to occipital plates were placed as paramedian. Instead, we inserted lateral mass screw to the sites where occipital screws were inserted on the occipital plate, thereby creating a site where extra rod could be bound.When C2 translaminar screw is inserted, screw caps remain on the median plane, which makes them difficult to bind to contralateral system. These bind directly to occipital plate without any connection from this region to the contralateral system.Advantages of this technique include easy insertion of C2 translaminar screws, presence of increased screw sizes, and exclusion of pullout forces onto the screw from neck movements. Another advantage of the technique is the median placement of the rod; i.e., thick part of the occipital bone is in alignment with axial loading. Conclusion : We believe that this technique, which could be easily performed as adjuvant to classical stabilization surgery with no need for special screw and rod, may improve distraction force in patients with low bone density.

• Journal of Korean Neurosurgical Society
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• v.57 no.6
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• pp.460-464
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• 2015

Objective : Bilateral C1 lateral mass and C2 pedicle screw fixation (C1LM-C2P) is an ideal technique for correcting atlantoaxial instability (AAI). However, the inevitable situation of vertebral artery injury or unfavorable bone structure may necessitate the use of unilateral C1LM-C2P. This study compares the fusion rates of the C1 lateral mass and C2 pedicle screw in the unilateral and bilateral methods. Methods : Over five years, C1LM-C2P was performed in 25 patients with AAI in our institute. Preoperative studies including cervical X-ray, three-dimensional computed tomography (CT), CT angiogram, and magnetic resonance imaging were performed. To evaluate bony fusion, measurements of the atlanto-dental interval (ADI) and CT scans were performed in the preoperative period, immediate postoperative period, and postoperatively at 1, 3, 6, and 12 months. Results : Unilateral C1LM-C2P was performed in 11 patients (44%). The need to perform unilateral C1LM-C2P was due to anomalous course of the vertebral artery in eight patients (73%) and severe degenerative arthritis in three patients (27%). The mean ADI in the bilateral group was 2.09 mm in the immediate postoperative period and 1.75 mm in 12-months postoperatively. The mean ADI in the unilateral group was 1.82 mm in the immediate postoperative period and 1.91 mm in 12-months postoperatively. Comparison of ADI measurements showed no significant differences in either group (p=0.893), and the fusion rate was 100% in both groups. Conclusion : Although bilateral C1LM-C2P is effective for AAI from a biomechanical perspective, unilateral screw fixation is a useful alternative in patients with anatomical variations.

• Journal of the Korean institute of surface engineering
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• v.41 no.6
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• pp.292-300
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• 2008

Dental implant system is composed of abutment, abutment screw and implant fixture connected with screw. The problems of loosening/tightening and stability of abutment screw depend on surface characteristics, like a surface roughness, coating materials and friction resistance and so on. For this reason, surface treatment of abutment screw has been remained research problem in prosthodontics. The purpose of this study was to investigate the stability of TiN and WC coated dental abutment screw, abutment screw was used, respectively, for experiment. For improving the surface characteristics, TiN and WC film coating was carried out on the abutment screw using EB-PVD and sputtering, respectively. In order to observe the coating surface of abutment screw, surfaces of specimens were characterized, using field emission scanning electron microscope(FE-SEM) and energy dispersive x-ray spectroscopy(EDS). The stability of TiN and WC coated abutment screw was evaluated by potentiodynamic, and cyclic potentiodynamic polarization method in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The corrosion potential of TiN coated specimen was higher than those of WC coated and non-coated abutment screw. Whereas, corrosion current density of TiN coated screws was lower than those of WC coated and non-coated abutment screw. The stability of screw decreased as following order; TiN coating, WC coating and non-coated screw. The pitting potentials of TiN and WC coated specimens were higher than that of non-coated abutment screw, but repassivation potential of WC coated specimen was lower than those of TiN coated and non-coated abutment screws due to breakdown of coated film. The degree of local ion dissolution on the surface increased in the order of TiN coated, non-coated and WC coated screws.

• Journal of Trauma and Injury
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• v.19 no.2
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• pp.164-172
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• 2006

Background: The authors conducted a retrospective study to evaluate the mechanism of injury, the surgical techniques, the clinical features, the combined injuries, the treatment results, and the surgical complications in patients with atlantoaxial fracture/subluxations. Methods: The authors reviewed 71 cervical fracture/dislocations during a four-year period from September 2002 to August 2006. Among them, there were twenty one C1,2 fracture/subluxations. There were thirteen men (mean age : 43.5 years) and eight women (mean age : 50 years). Their follow-up period was at least 6 months, and the mean follow-up period was 9.6 months. Gardner-Wells tongs traction was used in all patients immediately on presentation. Surgical treatment was performed, depending on the pathologic conditions. Results: Of all 21 cases, 14 cases were injured in motor vehicle accidents, 5 were falls, and 2 were miscellaneous. There were four C1 fracture (5.6%), fourteen C2 fracture (66.7%), one C1 and 2 combined fracture (4.8%), and one C1-2 subluxation (4.8%). The C1 fractures in our series were classified as two Jefferson's fractures and two C1 lateral mass fracture. The C2 fractures were classified as one odontoid type I fracture, two odontoid type II fractures, five odontoid type III fractures, one hangman's fracture, and four C2 body tear-drop fractures. Atlantoaxial fractures were associated with six (28.6%) head injuries, four (19.0%) other spinal injuries, two (9.5%) chest injuries, and three (14.3%) spinal cord injuries. Surgical treatment was performed in nine cases, which included anterior odontoid screw fixation in two cases, transarticular screw fixation with iliac bone graft in one case, posterior fixation by using C2 pedicle screw and C3 lateral mass screw in three cases, lateral mass screw fixation C1-2 with iliac bone graft in one case, O(occipito)-C1-3-4 screw fixation in one case, posterior C2-3 wiring with allograft in one case, and halo vest in six cases. Conservative management was used in the rest of the patients in our trials. Bone fusion was complete in all cases. There were no operation-related complication, except one pin site infection in the case of halo vest. Conclusion: In this study, the choice of appropriate treatment according to the fracture types resulted in safe and effective management of unique atlantoaxial fracture/subluxations.

• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.23-28
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• 2007

Wood fuel must be dried before combustion to minimize the energy loss. Sawdust of Japanese red pine was dried in a direct contact thermal screw dryer to investigate the drying characteristics of sawdust as a raw material for bio-fuel. Average drying rate and energy efficiency was 1.4%/min and 69.23% at $100^{\circ}C$, respectively, and those at $120^{\circ}C$ was 2.1%/min and 71.03%, respectively.

• Journal of Korean Neurosurgical Society
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• v.41 no.4
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• pp.248-251
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• 2007

Atlantoaxial rotatory dislocation [AARD] is an uncommon disorder of childhood in which clinical diagnosis is generally difficult and often made late. It is very rare in adults because of the unique biomechanical features of the atlantoaxial articulation. We report a case of post-traumatic AARD in an adult. Reduction was difficult to obtain by skull traction and gentle manipulation. Therefore, the patient was treated surgically by an open reduction, transpedicular screw fixation, and posterior C1-2 wiring with graft. The normal atlantoaxial relation was restored with disappearance of torticollis. Postoperatively, the patient remains neurologically intact and has radiographic documentation of fusion. Atlantoaxial transpedicular screw fixation can be one of the treatment options for the AARD.

• Journal of Korean Neurosurgical Society
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• v.29 no.2
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• pp.280-285
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• 2000

Posterior transarticular screw fixation for atlantoaxial instability due to trauma or rheumatoid arthritis provides immediate rigid fixation of the C1-2 vertebral segment while preserving motion between the occiput and C1. This technique provides more resistance to translational and rotational forces than wiring technique. However, the technique of transarticular screw fixation is inherently demanding because of the complex anatomy of the occipitocervical region and vertebral artery(VA) at risk for arterial damage. VA injury may lead to serious subsequent neurological deficits and possibly death from bilateral VA injury. We report a case of a vertebral artery-to-epidural venous plexus fistula after posterior transarticular screw fixation which was treated with balloon occlusion.

• Journal of Ginseng Research
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• v.37 no.2
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• pp.219-226
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• 2013

This study was conducted to investigate the effect of extrusion conditions (moisture content 20% and 30%, screw speed 200 and 250 rpm, barrel temperature $115^{\circ}C$ and $130^{\circ}C$) on the acidic polysaccharide, ginsenoside contents and antioxidant properties of extruded Korean red ginseng (KRG). Extruded KRGs showed relatively higher amounts of acidic polysaccharide (6.80% to 9.34%) than non-extruded KRG (4.34%). Increased barrel temperature and screw speed significantly increased the content of acidic polysaccharide. The major ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rf, Rg2s, Rg3s, Rh1, and Rg3r) of KRG increased through extrusion, while the ginsenoside (Rg1) decreased. The EX8 (moisture 30%, screw speed 250 rpm, and temperature $130^{\circ}C$) had more total phenolics and had a better scavenging effect on 2,2-diphenyl-1-picrylhydrazyl radicals than those of extruded KRG samples. The extrusion cooking showed a significant increase (6.8% to 20.9%) in reducing power. Increased barrel temperature significantly increased the values of reducing power, the highest value was 1.152 obtained from EX4 (feed moisture 20%, screw speed 250 rpm, and temperature $130^{\circ}C$). These results suggest that extrusion conditions can be optimized to retain the health promoting compounds in KRG products.

• Journal of Korean Neurosurgical Society
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• v.43 no.2
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• pp.111-113
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• 2008

Recently, Harms and Melcher modified Goel's approach, the C1 lateral mass and C2 pedicle screw fixation, and the new technique is currently in favor among neurosurgeons. Comparing to the advantages of Harms construct, the disadvantages were not extensively investigated. We experienced a patient with severe occipital pain developed after the C1 lateral mass screw placement for the traumatic atlantoaxial instability. We reviewed literatures about Harms construct with focus on the occipital neuralgia as a postoperative complication and suggest here technical tips to avoid the troublesome pain.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.1
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• pp.119-130
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• 2007

Statement of problem: A few dry lubricants were applied to abutment screws for the improvement of joint stability. Purpose: The purpose of this study was to evaluate the surface change and fit of TiN-Coated abutment screw through the examination of tested screws in the field emission scanning electron microscope(FE-SEM;Netherland, Phillips co., model:XL 30 SFEG) after repeated closing and opening. Materials and method: Titanium(3i/implant Innovations Inc, USA) and Gold-Tite abutment screws(3i/implant Innovations Inc, USA) were selected for Group A and C respectively. TiN coated titanium abutment screws were also divided into two groups, Group B and D. Abutment screws of each group and the fit of abutment screw/implant fixture/abutment were observed on FE-SEM after repeated closing and opening test respectively. Results: 1. The abutment screws of TiN coated groups(Group B and D) showed more remarkable wear resistance in the threads of the screw than those of the other group(Group A and C). 2. There were more severe wear and defect of TiN coating in Group D tightened to 32 Ncm than Group B to 20 Ncm. 3. There was no difference in the fit of abutment screw/fixture/abutment among four groups, Group A, Group B, Group C and Group D. Conclusion: Under the conditions of this study, it is suggested that TiN coating of abutment screw be clinically acceptable and be expected to reduce the risk of abutment screw loosening. TiN coating of abutment screw showed good resistance against wear and the adequate fit of abutment screw/implant fixture/abutment.