• Journal of Korean Neurosurgical Society
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• v.49 no.6
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• pp.351-354
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• 2011

Objective : This investigation was conducted to evaluate a new, safe entry point for the C2 pedicle screw, determined using the anatomical landmarks of the C2 lateral mass, the lamina, and the isthmus of the pars interarticularis. Methods : Fifteen patients underwent bilateral C1 lateral mass-C2 pedicle screw fixation, combined with posterior wiring. The C2 pedicle screw was inserted at the entry point determined using the following method : 4 mm lateral to and 4 mm inferior to the transitional point (from the superior end line of the lamina to the isthmus of the pars interarticularis). After a small hole was made with a high-speed drill, the taper was inserted with a 30 degree convergence in the cephalad direction. Other surgical procedures were performed according to Harm's description. Preoperatively, careful evaluation was performed with a cervical X-ray for C1-C2 alignment, magnetic resonance imaging for spinal cord and ligamentous structures, and a contrast-enhanced 3-dimensional computed tomogram (3-D CT) for bony anatomy and the course of the vertebral artery. A 3-D CT was checked postoperatively to evaluate screw placement Results : Bone fusion was achieved in all 15 patients (100%) without screw violation into the spinal canal, vertebral artery injury, or hardware failure. Occipital neuralgia developed in one patient, but this subsided after a C2 ganglion block. Conclusion : C2 transpedicular screw fixation can be easily and safely performed using the entry point of the present study. However, careful preoperative radiographic evaluation, regardless of methods, is mandatory.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.23-26
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• 1995

The objectives of the present study are 1)to find the effect of the diameter of transpedicular screws on their fixational strength in pedicles under static pull-out loading, 2)to determine the biomechanical correlation between the pedicle diameter and the screw diameter, and 3)to find the effects of other factors in the screw design, such as materials, screw pitch, thread height and shape on their fixational strength. Biomechanical tests (Test I) were performed to evaluate the effect of the screw diameter on pull-out strength by using 60 porcine pedicls and six groups of custom-made pedicle screws with different diameters (the major and the minor diameter of the screws used in the testing varied from 4mm upto 9mm and from 3mm upto 8mm, respectively) while all other factors (materials, screw pitch, thread height and shape etc.) were fixed. In Test II, by using 61 porcine pedicles, the relationship between the ratio of the pedicle diameter and the screw diameter(=aspect ratio) of the custum-made screw and the pull-out strength of the screw was investigated. Test III was performed with 94 porcine pedicles and 8 different types of the commercial screws from 6 major productors in order to determine the effect of the screw diameter, pitch and the thread shape on the pull-out strength of the screw, respectively. The results of Test I showed that the axial pull-out resistance of the screw could be increased prportionaly to the screw diameter(P<0.05). But this increase in the pull-out resistance did not found when the screws of 4mm or 9mm in the diameter were employed. It was found from the results of Test II that the screws had its maximum pull-out resistant force when the aspect ratio ranging 40 - 69% (P<0.05). based on the results for the major diameter against the minor diameter of screw, the maximal pull-out resistance was found at 60-65% (P<0.05). According to these biomechanical testing results, it seems that the screw with a moderately large pitch is more desirable and the buttress-shaped screw can provide stronger fixation than the V-shape one can, if other designal factor and conditions were fixed.

• Journal of Korean Neurosurgical Society
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• v.52 no.4
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• pp.359-364
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• 2012

Objective : Transpedicular screw fixation has some disadvantages such as postoperative back pain through wide muscle dissection, long operative time, and cephalad adjacent segmental degeneration (ASD). The purposes of this study are investigation and comparison of radiological and clinical results between interspinous fusion device (IFD) and pedicle screw. Methods : From Jan. 2008 to Aug. 2009, 40 patients underwent spinal fusion with IFD combined with posterior lumbar interbody fusion (PLIF). In same study period, 36 patients underwent spinal fusion with pedicle screw fixation as control group. Dynamic lateral radiographs, visual analogue scale (VAS), and Korean version of the Oswestry disability index (K-ODI) scores were evaluated in both groups. Results : The lumbar spine diseases in the IFD group were as followings; spinal stenosis in 26, degenerative spondylolisthesis in 12, and intervertebral disc herniation in 2. The mean follow up period was 14.24 months (range; 12 to 22 months) in the IFD group and 18.3 months (range; 12 to 28 months) in pedicle screw group. The mean VAS scores was preoperatively $7.16{\pm}2.1$ and $8.03{\pm}2.3$ in the IFD and pedicle screw groups, respectively, and improved postoperatively to $1.3{\pm}2.9$ and $1.2{\pm}3.2$ in 1-year follow ups (p<0.05). The K-ODI was decreased significantly in an equal amount in both groups one year postoperatively (p<0.05). The statistics revealed a higher incidence of ASD in pedicle screw group than the IFD group (p=0.029) Conclusion : Posterior IFD has several advantages over the pedicle screw fixation in terms of skin incision, muscle dissection and short operative time and less intraoperative estimated blood loss. The IFD with PLIF may be a favorable technique to replace the pedicle screw fixation in selective case.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.317-321
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• 2009

Objective : In the thoracic spine, insertion of a pedicle screw is annoying due to small pedicle size and wide morphological variation between different levels of the spine and between individuals. The aim of our study was to analyze radiologic parameters of the pedicle morphometry from T1 to T8 using computed tomographic myelography (CTM) in Korean population. Methods : For evaluation of the thoracic pedicle morphometry, the authors prospectively analyzed a consecutive series of 26 patients with stable thoracic spines. With the consent of patients, thoracic CTM were performed, from T1 to T8. We calculated the transverse outer diameters and the transverse angles of the pedicle, distance from the cord to the inner cortical wall of the pedicle, and distance from the cord to the dura. Results : Transverse outer pedicle diameter was widest at T1 ($7.66{\pm}2.14\;mm$) and narrowest at T4 ($4.38{\pm}1.55\;mm$). Transverse pedicle angle was widest at T1 ($30.2{\pm}12.0^{\circ}$ and it became less than $9.0^{\circ}$ below T6 level. Theoretical safety zone of the medial perforation of the pedicle screw, namely, distance from the cord to inner cortical wall of the pedicle was more than 4.5 mm. Conclusion : Based on this study, we suggest that the current pedicle screw system is not always suitable for Korean patients. Computed tomography is required before performing a transpedicular screw fixation at the thoracic levels.

• Journal of Korean Neurosurgical Society
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• v.29 no.2
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• pp.255-260
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• 2000

The authors report a posttraumatic syringomyelia in a 30-year-old man who has complained pain, weakness of upper arm and dissociation sensory loss since 2 months before. He was underwent by decompressive laminectomy from T12 to L1, reduction of encroached bony fragments, transpedicular screw fixation from T12 to L2 and posterolateral bony fusion due to burst fracture of L1 at other hospital 3 years ago. Preoperative spinal MRI was highly suggestive of wide-spread, multiseptated syringomyelia from C3 to thoracolumbar junction. We performed wide decompressive laminectomy from T10 to L2 and subarachnoid space reconstrucion composed of microdissection of meningeal fibrosis widely, iatrogenic meningocele formation with lefting the dura mater opened for treatment of spinal-spinal pressure dissociation. Clinical manifestations and radiological findings of the patient were improved after the operation. This technique was thought to be superior to shunting procedures in cases of wide-spread, multiseptated post-traumatic syringomyelia.

• Journal of Korean Neurosurgical Society
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• v.55 no.1
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• pp.48-50
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• 2014

Brucellosis is caused by gram-negative, aerobic, non-motile, facultative, intracellular coccobacilli belonging to the genus Brucella. A 50-year-old man working as an employee was admitted to neurosurgery clinic with severe low back, radicular right leg pain and hypoesthesia in right L4-5 dermatomes for 2 months. Brucella tube agglutination (Wright) test was positive in serum sample of the patient with a titer of 1/640. Brucella melitensis was isolated from blood culture. X-ray and MRI of the lomber spine showed massive collapse of L4 vertebral body. Neural tissue was decompressed and then posterior L3-5 short segment transpedicular screw fixation and stabilization was performed. Brucella melitensis was isolated from microbiologic culture of pathologic specimen. Antibiotic therapy was given as doxycycline 200 mg/day and rifampicin 600 mg/day for 6 months. Brucellosis is a systemic zoonotic infection and still an important public health problem in many geographical parts of the world. Vertebral body collapse caused by brucellosis occurs very rarely but represents a neurosurgical emergency because of its potential for causing rapidly progressive spinal cord compression and permanent paralysis. Neurosurgeons, emergency department personnel as well as infectious disease specialists should always keep a high index of suspicion and include brucellosis in the differential diagnosis of vertebral body collapse.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.108-114
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• 2001

Objective : Posterior lumbar interbody fusion(PLIF) provides the favorable outcome to degenerative lumbar disease, especially isthmic spondylolisthesis. To determine the long-term effect of PLIF using psterior movable segment, we analysed the results of follow-up radiologic changes and surgical outcome retrospectively Patients and Method : During the past 11 years(1989. 1.-1999. 9.), 148 patients with symptomatic lumbar spondylolisthesis were managed at our department and the clinical wants were throughly recieved and final outcome is determined at last follow up. PLIF using antogenous bone(posterior movable segment, iliac bone and rib) were performed in 106 case. Results : After an average follow-up period of 33 months(range ; 15-58 months), the results were excellent in 66 cases, good in 37 cases, fair in 2 cases and poor in 1 cases. And the satisfactory results were 103 cases(98.2%) in PLIF,. Conclusion : In conclusion, patients who underwent PLIF with autologous bone graft had good clinical and radiological outcomes without significant neurological complications.

• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.605-610
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• 2001

Objective : The authors investigated the efficacy of the calcium sulfate(OsteoSet$^{(R)}$ pellets) as an autograft extender when used to perform posterolateral lumbar fusions. Patients and Methods : Twenty patients who underwent lumbar posterolateral arthrodesis for various spinal diseases between October 1999 and March 2000 were evaluated. Arthrodesis was performed by transpedicular screw fixation and bone grafting with a mixture of autograft + calcium sulfate in a 1 : 1 ratio. At time intervals of 1, 2, 3, and 6 months, postoperative radiographs were obtained to review the resorption of calcium sulfate and the evidence of fusion. A modified Lenke scale was used to assess the status of the fusion. Results : At 2 months after operation, the average modified Lenke scale score for the OsteoSet$^{(R)}$ pellets group was 3.8. However at 6 months after operation, the average modified Lenke scale score for the OsteoSet$^{(R)}$ pellets group was 1.8. Resorption of calcium sulfate pellets was revealed in all cases at 6 months after surgery. Conclusion : It is presumed that a combination of calcium sulfate and autograft can play a role as an effective autograft extender in the posterolateral spinal fusion.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1262-1266
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• 2000

Objective : Flat back syndrome constitutes a syndrome complex characterized by the loss of normal lumbar lordosis. Various techniques of correction for flat back syndrome have been reported. Posterior extension osteotomy has certain drawbacks. Forceful hyperextension of the spine may result in vascular complications such as rupture of the aorta or the inferior vena cava and stretching of superior mesenteric artery, and pseudoarthrosis. We describe a rationale and technique of transvertebral posterior extension osteotomy to avoid complications of posterior extension osteotomy and to achieve an correction of 30 degrees of flat back syndrome. Method : A 63-year-old woman with degenerative lumbar kyphosis presented with low back pain, thigh pain, knee pain and walking difficulty. Transpedicular fixation from L1 vertebra to S1 vertebra was accomplished for lumbar degenerative kyphosis. After 6 months, the patient presented with flat back syndrome. A second operation was performed with transvertebral posterior extension osteotomy. Result : With short segemental fusion, early bone fusion and correction of 30 degrees were achieved. Conclusion : Transvertebral posterior extension osteotomy provide an 30-60 degrees of correction of flat back syndrome. This technique is considered to be good method for the revision of lumbar degenerative kyphosis.

• Journal of Korean Neurosurgical Society
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• v.42 no.1
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• pp.6-10
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• 2007

Objective : The purpose of this study was to determine the effect of bone cement augmentation of pedicular screwing in severe osteoporotic spondylolisthetic patients. Methods : Twenty patients with spondylolisthesis (8 : spondylolytic spondylolisthesis 12 : degenerative spondylolisthesis) who had undergone pedicular screwing and interbody fusion for osteoporotic lumbar spine (T-score on bone mineral density<-3.0) from 2002 to 2005 were reviewed. Mean age was 62.3 years with 3 male and 17 female patients. Average follow-up period was 14 months. Average T-score on bone mineral density (BMD) was -3.62. After decompression of neural elements, about 6cc of polymethylmethacrylate (PMMA) was injected into the each vertebral body through transpedicular route. All patients underwent one level interbody fusion and pedicular screw fixation. Clinical outcome was assessed using Oswestry Disability Index (ODI) on the last clinical follow-up. In addition, a modified MacNab's grading criteria was used to objectively assess patient's outcome postoperatively. Radiographic analysis of sagittal contour was assessed preoperatively, immediately postoperatively, and at final follow-up including fusion rate. Results : Eighteen of 20 patients were graded as excellent or good according to the modified MacNab's criteria. An significant improvement of ODI was achieved in both groups. Mean sagittal angle at the preoperative state, postoperative state and at the last follow-up state was $11.0^{\circ},\;20.1^{\circ}$ and $18.3^{\circ}$, respectively, with mean sagittal angle correction gain $7.3^{\circ}$. Firm fusion was achieved in all patients. There were one compression fracture above the fused segment after 6 months follow-up and one case of seroma. But there were no postoperative complications related to bone cement leakage and pedicular screwings such as screw pullout or screw cut-up. Conclusion : Bone cement augmentation of pedicular screwing can be an effective procedure for osteoporotic lumbar spine in spondylolisthetic patients.