• Journal of Korean Neurosurgical Society
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• v.40 no.5
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• pp.387-390
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• 2006

We report a case of C1-2 instability with a bilateral high-riding transverse foramen that was treated with rod-screw fixation using a technique of translaminar rigid screw fixation of the axis. It is believed that a C1-2 fixation with bilateral C-2 translaminar screws has an important advantage over previously reported techniques of C1-2 fixation by eliminating the risk of injury to the vertebral artery during C2 screw placement.

• Journal of Korean Neurosurgical Society
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• v.41 no.2
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• pp.141-144
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• 2007

A vertebral arte [VA] injury presents a difficult problem in atlantoaxial fixation. Recent technical reports described posterior C2 fixation using bilateral, crossing C2 laminar screws. The translaminar screw technique has the advantages of producing little risk of VA injury and the unconstrained screw placement. In addition, biomechanical studies have demonstrated the potential of the translaminar screw technique to provide a firmer construct that is equivalent to methods currently used. We report the successful treatment of C1-2 instability with a left-side high-riding VA. Because of the potential risk of VA injury, we performed a posterior C1-2 fixation with a combination of pedicle screws and a laminar screw in C2. We first placed bilateral C1 lateral mass screws and a right-side C2 pedicle screw. However, placement of the left- side C2 pedicle screw was technically difficult due to a narrow isthmus and pedicle. A laminar screw was inserted instead and authors believe that this posterior C1-C2 fixation with a combination of pedicle screws and a laminar screw in C2 can be a useful alternative technique for the treatment of C1-C2 instability in the presence of a unilateral high-riding VA.

• Journal of Korean Neurosurgical Society
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• v.47 no.3
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• pp.221-223
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• 2010

C1 lateral mass and C2 pedicle (C1LM-C2P) fixation is a relatively new technique for atlantoaxial stabilization. Complications from C1LM-C2P fixation have been rarely reported. The authors report unilateral rod migration into the posterior fossa as a rare complication after this posterior C1-C2 stabilization technique. A 23-year-old man suffered severe head trauma and cervical spine injury after vehicle accident. He was unconscious for 2 months and regained consciousness. He underwent C1LM-C2P fixation for stabilization of type II odontoid process fracture described by Harms. The patient recovered without a major complication. Twenty months after operation, brain computed tomogram performed at psychology department for disability evaluation showed rod migration into the right cerebellar hemisphere. The patient had mild occipital headache and dizziness only regarding the misplaced rod. He refused further operation for rod removal. To our knowledge, this complication is the first report regarding rod migration after Harms method. We should be kept in mind the possibility of rod migration, and C1LM-C2P fixation should be performed with meticulous technique and long-term follow-up.

• Journal of Korean Neurosurgical Society
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• v.51 no.3
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• pp.177-181
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• 2012

We present a case of an athetoid cerebral palsy with quadriparesis caused by kyphotic deformity of the cervical spine, severe spinal stenosis at the cervicomedullary junction, and atlantoaxial instability. The patient improved after the first surgery, which included a C1 total laminectomy and C-arm guided righ side unilateral C1-2 transarticular screw fixation. C1-2 fixation was not performed on the other side because of an aberrant and dominant vertebral artery (VA). Eight months after the first operation, the patient required revision surgery for persistent neck pain and screw malposition. We used intraoperative VA angiography with simultaneous fluoroscopy for precise image guidance during bilateral C1-2 transarticular screw fixation. Intraoperative VA angiography allowed the accurate insertion of screws, and can therefore be used to avoid VA injury during C1-2 transarticular screw fixation in comorbid patients with atlantoaxial deformities.

• Journal of Korean Neurosurgical Society
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• v.37 no.3
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• pp.201-206
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• 2005

Objective: To evaluate the accuracy and safety of C1-C2 transarticular screw insertion, we retrospectively review surgical records and postoperative radiological findings. Methods: From January 2001 to October 2003, the C1-C2 transarticular screw fixation and posterior wiring with iliac bone grafts was performed in 16 patients. 6 patients had rheumatoid arthritis which caused cervical instability, 3 patients had os odontoideum, 3 patients had type 2 odontoid process fracture, 3 patients had traumatic transverse ligament injury and 1 patients who had been managed with C1-C2 wire fixation had psoriatic arthritis. Results: Osseous fusion was documented in 15 patients(93.8%). Only one patient was recorded screw loosening because of postoperative infection. One patient had only one screw placed because of abnormal anatomical structure, one patients was breakage of a Kirschner wire, and one screw was medial location to lateral mass of C1, but clinical results was excellent and radiological instability was not noted. Conclusion: The author's experience demonstrates that C1-C2 transarticular screw fixation with wired bone graft is a safe procedure with higher fusion rate but precaution is needed to avoid the neural damage, vertebral artery injury, and hardware failure.

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.341-347
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• 2011

Objective : The purpose of this retrospective study was to evaluate the efficacy and safety of atlantoaxial stabilization using a new entry point for C2 pedicle screw fixation. Methods : Data were collected from 44 patients undergoing posterior C1 lateral mass screw and C2 screw fixation. The 20 cases were approached by the Harms entry point, 21 by the inferolateral point, and three by pars screw. The new inferolateral entry point of the C2 pedicle was located about 3-5 mm medial to the lateral border of the C2 lateral mass and 5-7 mm superior to the inferior border of the C2-3 facet joint. The screw was inserted at an angle $30^{\circ}$ to $45^{\circ}$ toward the midline in the transverse plane and $40^{\circ}$ to $50^{\circ}$ cephalad in the sagittal plane. Patients received followed-up with clinical examinations, radiographs and/or CT scans. Results : There were 28 males and 16 females. No neurological deterioration or vertebral artery injuries were observed. Five cases showed malpositioned screws (2.84%), with four of the screws showing cortical breaches of the transverse foramen. There were no clinical consequences for these five patients. One screw in the C1 lateral mass had a medial cortical breach. None of the screws were malpositioned in patients treated using the new entry point. There was a significant relationship between two group (p=0.036). Conclusion : Posterior C1-2 screw fixation can be performed safely using the new inferolateral entry point for C2 pedicle screw fixation for the treatment of high cervical lesions.

• The Korean Journal of Ecology
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• v.18 no.3
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• pp.323-332
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• 1995

Effects of wintering and temperature on nitrogen fixation activity of nodules of Melilotus suaveolens Ledeb. grown in the field and growth chamber conditions were investigated. The biennial plants transfered to the growth chamber from winter field recovered the activity in 3 weeks of incubation and attained the maximum rate of $153{\mu}mol\;C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$ in 5 weeks. When root nodules which adapted to different temperatures, were pretreated with 10, 20 and $30^{\circ}C$ for 1 hour, and then transfered to $30^{\circ}C$, nitrogen fixation activity was promoted in the nodules exposed to lower field temperature ($12^{\circ}C$) with 1$0^{\circ}C$ pretreatment. M. suaveolens maintained nitrogen fixation activity in the wide range of temperatures, and was more tolerant to lower temperature than those of other woody leguminous plants, Diurnal changes of nodule activity showed increase with sunrise and decrease with sunset during spring and autumn, but the activity was inhibited during July and August because of high temperature with stron irradiation. Nitrogen fixation activity of annual plant appeared in mid-April, and showed two peaks (104 and 43 mol $C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$) in July and September, and then disappeared after October. Nitrogen fixation activity of biennial plant reappeared in mid-March after wintering and attained two peaks (102 and 82 ${\mu}mol\;C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$) in April and June of flowering period, and then disappeared after July due to plant withering by severe drought.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1469-1475
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• 2000

Objective : The goal of this study was to evaluate the clinical outcome of the posterior C1-2 transarticular screw fixation without C1-2 sublaminar wiring in atlantoaxial instability. Methods : Between Apr. 1995 and Feb. 2000, we used this technique in treat randomly selected 17 patients (11 men, 6 women) who had atlantoaxial instability. The causes of instability were : type II-A odontoid process fracture(10 cases) ; type II-P odontoid process fracture(1 case) ; Os odontoideum(2 cases) ; transverse ligament laxity due to rheumatoid disease(1 case) ; and, transverse ligament injury without bone fracture(3 cases). All cases were operated with posterior C1-2 transarticular screw fixation with 3.5mm cortical screw and interlaminar iliac graft without sublaminar wire fixation. The mean follow-up period was 28 months(5 to 58 months) and the mean age at the time of operation was 41 years(15 to 68 years). All Patients were allowed to ambulate with Philadelphia neck collar on the first post-operation day. Results : Bony fusion was successfully achieved in all cases demonstrated at 3-month follow-up studies. There was no operative mortality or morbidity. Conclusion : The authors conclude that the posterior transarticular screw fixation without C1-2 sublaminar wiring provide adequate stability with high bony union rate in atlantoaxial instability of various causes.

• Journal of Korean Neurosurgical Society
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• v.49 no.6
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• pp.345-350
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• 2011

Objective : It is debatable whether an anterior oblique fracture orientation is really a contraindication to anterior odontoid screw fixation. The purpose of this study was to investigate the feasibility of anterior odontoid screw fixation of type II and rostral shallow type III fracture with an anterior oblique fracture orientation. Methods : The authors evaluated 16 patients with type II and rostral shallow type III odontoid fracture with an anterior oblique fracture orientation. Of these 16 patients, 8 (group 1) were treated by anterior odontoid screw fixation, and 8 (group 2) by a posterior C1-2 arthrodesis. Results : Of the 8 patients in group 1, seven patients achieved solid bone fusion (87.5%), and one experienced screw back-out of the C-2 body two months after anterior screw fixation. All patients treated by posterior C1-C2 fusion in group 2 achieved successful bone fusion. Mean fracture displacements and fracture gaps were not significantly different in two groups. (p=0.075 and 0.782). However, mean fracture orientation angles were $15.3{\pm}3.2$ degrees in group 1, and $28.6{\pm}8.1$ degrees in group 2 (p=0.002), and mean fragment angulations were $3.2{\pm}2.1$ degrees in group 1, and $14.8{\pm}3.7$ degrees in group 2 (p=0.001). Conclusion : Even when the fracture lines of type II and rostral shallow type III fractures are oriented in an anterior oblique direction, anterior odontoid screw fixation can be feasible in carefully selected patients with a relatively small fracture orientation angle and relatively small fragment angulation.

• Journal of Korean Neurosurgical Society
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• v.50 no.6
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• pp.528-531
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• 2011

Although posterior segmental fixation technique is becoming increasingly popular, surgical treatment of craniovertebral junctional disorders is still challenging because of its complex anatomy and surrounding critical neurovascular structures. Basilar invagination is major pathology of craniovertebral junction that has been a subject of clinical interest because of its various clinical presentations and difficulty of treatment. Most authors recommend a posterior occipitocervical fixation following transoral decompression or posterior decompression and occipitocervical fixation. However, both surgical modalities inadvertently sacrifice C0-1 and C1-2 joint motion. We report two cases of basilar invagination reduced by the vertical distraction between C1-2 facet joint. We reduced the C1-2 joint in an anatomical position and fused the joint with iliac bone graft and C1-2 segmental fixation using the polyaxial screws and rods C-1 lateral mass and the C-2 pedicle.