• Journal of Korean Neurosurgical Society
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• v.63 no.6
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• pp.777-783
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• 2020

Objective : To compare the accuracy and breach rates of freehand (FH) versus navigated (NV) pedicle screws in the thoracic and lumbar spine in patients with metastatic spinal tumors. Methods : A retrospective review of adult patients who underwent pedicle screw fixation in the thoracic or lumbar spine for metastatic spinal tumors between 2012 and 2018 was conducted. Breaches were assessed based on the Gertzbein and Robbins classification and only screws placed >4 mm outside of the pedicle wall (lateral or medial) were considered breached. Results : A total of 62 patients received 547 pedicle screws (average 8 per patient) - 34 patients received 298 pedicle screws in the FH group and 28 patients received 249 screws in the NV group. There were 40/547 breaches, corresponding to a breach and accuracy rate of 7.3% and 92.7%, respectively. The breach rate was 9.7% in the FH group and 4.4% in the NV group (chi-squared test, p=0.017); this corresponded to an accuracy rate of 90.3% and 95.6%, respectively. Only one patient from the overall cohort (in the FH group) required revision surgery due to a medial breach abutting the spinal cord (1.6% of all patients; 2.9% of FH patients); no patient suffered organ, vessel, or neurological injury from screw breaches. Conclusion : Navigated pedicle screw placement in patients with metastatic spinal tumors has a significantly higher radiographic accuracy compared to the FH technique. However, the revision surgery was low and no patient suffered from clinically-relevant breach. Navigation also offers the advantage of real-time localization of spinal tumors and aids in targeting and resection of these lesions.

• Journal of Korean Neurosurgical Society
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• v.62 no.4
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• pp.467-475
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• 2019

Objective : There is a lack of knowledge regarding whether decompression is necessary in treating patients with epidural spinal cord compression (ESCC) grade 2. The purpose of this study was to compare the outcomes of minimally invasive surgery (MIS) without decompression and conventional open surgery (palliative laminectomy) for patients with hepatocellular carcinoma (HCC) spinal metastasis of ESCC grade 2. Methods : Patients with HCC spinal metastasis requiring surgery were retrospectively reviewed. Patients with ESCC grade 2, medically intractable mechanical back pain, a Nurick grade better than 3, 3-6 months of life expectancy, Tomita score ${\geq}5$, and Spinal Instability Neoplastic Score ${\geq}7$ were included. Patients with neurological deficits, other systemic illnesses and less than 1 month of life expectancy were excluded. Thirty patients were included in the study, including 17 in the open surgery group (until 2008) and 13 in the MIS group (since 2009). Results : The MIS group had a significantly shorter operative time ($94.2{\pm}48.2minutes$ vs. $162.9{\pm}52.3minutes$, p=0.001), less blood loss ($140.0{\pm}182.9mL$ vs. $1534.4{\pm}1484.2mL$, p=0.002), and less post-operative intensive care unit transfer (one patient vs. eight patients, p=0.042) than the open surgery group. The visual analogue scale for back pain at 3 months post-operation was significantly improved in the MIS group than in the open surgery group ($3.0{\pm}1.2$ vs. $4.3{\pm}1.2$, p=0.042). The MIS group had longer ambulation time ($183{\pm}33days$ vs. $166{\pm}36days$) and survival time ($216{\pm}38days$ vs. $204{\pm}43days$) than the open surgery group without significant difference (p=0.814 and 0.959, respectively). Conclusion : MIS without decompression would be a good choice for patients with HCC spinal metastasis of ESCC grade 2, especially those with limited prognosis, mechanical instability and no neurologic deficit.

• Journal of Korean Neurosurgical Society
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• v.41 no.3
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• pp.157-160
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• 2007

Objective : The purpose of this study was to evaluate the efficacy and safety of the surgical treatment for lumbar spinal stenosis in elderly patients. Methods : The authors reviewed the medical records of 49 patients older than 65 years of age with lumbar spinal stenosis who underwent surgical treatment from January 2002 to December 2004 in our institute. Results : Average age of patients was 70 years old [32 women, 17 men]. Twenty-four patients had chronic medical disorders. All patients were operated under the general anesthesia of these, 29 patients underwent decompressive laminectomy and decompressive laminectomy with instrumentation and fusion in 20 patients. The mean operation time was 193.5 minutes, mean estimated blood loss was 378cc and mean postoperative hospital stay length was 15.3 days. The mean follow-up duration was 11.9 months. The evaluation of outcome was assessed by Macnab classification. At first month after operation, the outcome showed excellent in 7 [14.3%]. good in 35 [71.4%], fair in 5 [10.2%], and poor in 2 [4.1%]. And at 6 months after operation, 17 patients were lost in follow-up, the outcome showed excellent in 4 [12.5%], good in 25 [78.1%], fair in 3 [9.4%], and no poor cases. There was no significant difference between outcome of laminectomy alone and that of laminectomy with fusion. Six patients [12.2%] experienced postoperative complications which included wound infection [3], nerve root injury [1], disc herniation [1], and reoperation due to insufficient decompression [1]. There were no deaths related to operation. Conclusion : We conclude that the surgical treatment for lumbar spinal stenosis in elderly patients can provide good results with acceptable morbidity when carefully selected. In addition, decision on lumbar spinal fusion should not be against solely on advanced age.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.317-325
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• 2007

Objective : The purpose of the study was to determine the clinical effects of anterior radical debridement on a series of patients with spontaneous spinal infection. Methods : We retrospectively analyzed the clinical characteristics of 32 patients who underwent surgical treatment from January 2000 to December 2005 in our department. The average follow-up Period was 33.4 months (range, 6 to 87 months). Thirty-two patients presented with the following : 23 cases with pyogenic spondylitis, eight with tuberculous spondylitis and one with fungal spondylitis. The indications for surgery were intractable pain, failure of medical management, neurological impairment with or without an associated abscess, vertebral destruction causing spinal instability and/or segmental kyphosis. Results : The study included 15 (46.9%) males and 17 (53.1%) females ranging in age from 26 to 75 years (mean, 53.1 years). Diabetes mellitus (DM) and pulmonary Tbc were the most common predisposing factors for pyogenic spondylitis and tuberculous spondylitis. Staphylococcus aureus (13%) was the main organism isolated. The most prevalent location was the lumbar spine (75%). Changes in the pain score, Frankel's classification, and laboratory parameters demonstrated a significant clinical improvement in all patients. However, there were recurrent infections in two patients with tuberculous spondylitis and inappropriate debridement and intolerance of medication and noncompliance. Autologous rib, iliac bone and allograft(fibular) were performed in most patients. However, 10 patients were grafted using a titanium mesh cage after anterior radical debridement. There were no recurrent infections in the 10 cases using the mesh cage with radical debridement. Conclusion : The findings of this study indicate that surgery based on appropriate surgical indications is effective for the control of spinal infection and prevention of recurrence with anterior radical debridement, proper drug use and abscess drainage.

• Journal of Korean Neurosurgical Society
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• v.60 no.2
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• pp.174-180
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• 2017

Objective : Proximal junctional kyphosis (PJK) is radiologic finding, and is defined as kyphosis of >$10^{\circ}$ at the proximal end of a construct. The aim of this study is to identify factors associated with PJK after segmental spinal instrumented fusion in adults with spinal deformity with a minimum follow-up of 2 years. Methods : A total of 49 cases of adult spinal deformity treated by segmental spinal instrumented fusion at two university hospitals from 2004 to 2011 were enrolled in this study. All enrolled cases included at least 4 or more levels from L5 or the sacral level. The patients were divided into two groups based on the presence of PJK during follow-up, and these two groups were compared to identify factors related to PJK. Results : PJK was observed in 16 of the 49 cases. Age, sex and mean follow-up duration were not statistically different between two groups. However, mean bone marrow density (BMD) and mean back muscle volume at the T10 to L2 level was significantly lower in the PJK group. Preoperatively, the distance between the C7 plumb line and uppermost instrumented vertebra (UIV) were no different in the two groups, but at final follow-up a significant intergroup difference was observed. Interestingly, spinal instrumentation factors, such as, receipt of a revision operation, the use of a cross-link, and screw fracture were no different in the two groups at final follow-up. Conclusion : Preoperative BMD, sagittal imbalance at UIV, and thoracolumbar muscle volume were found to be strongly associated with the presence of PJK.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1074-1079
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• 2000

We report a case of pyogenic spondylitis on L2 and L3 with diffuse epidural abscess up to T4 to L3 and large psoas abscess. A forty-nine-year old male was presented with progressive back pain, left flank pain and ab-dominal distention, weakness of the both legs and voiding and defecation difficulty during last 2 months. Initially multiple coronal hemilaminectomies from T4 to T12 were done for the treatment of diffuse thoracic epidural ab-scess. Then second operation via left retroperitoneal approach was performed for lumbar spondylitis and psoas abscess on third day after initial operation. After removal and curettage of pyogenic psoas and epidural abscess and spondylitis (L2-L3), iliac bone grafting with Keneda instrumentation from L1 to L4 was done simultaneously. Postoperative course has been unevenful without recurrent infection. The literature on diffuse epidural and large psoas abscess with pyogenic spondylitis are reviewed and instrumentation for stabilization of pyogenic spondylitis is also discussed.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.30-41
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• 2006

The goal of this work is to develop and test a robot-assisted surgery system for spinal fusion. The system is composed of a robot, a surgical planning system, and a navigation system. It plays the role of assisting surgeons for inserting a pedicle screw in the spinal fusion procedure. Compared to conventional methods for spinal fusion, the proposed surgical procedure ensures minimum invasion and better accuracy by using robot and image information. The robot plays the role of positioning and guiding needles, drills, and other surgical instruments or conducts automatic boring and screwing. Pre-operative CT images intra-operative fluoroscopic images are integrated to provide the surgeon with information for surgical planning. Some experiments employing the developed robotic surgery system are conducted. The experimental results confirm that the system is not only able to guide the surgical tools by accurately pointing and orienting the specified location, but also successfully compensate the movement of the patient due to respiration.

• Journal of Yeungnam Medical Science
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• v.15 no.1
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• pp.164-172
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• 1998

The Graf stabilization has been introduced in treating lumbar spinal disorder associated with posterior instability. This study reviewed some problems of the Graf instrumentation as a soft stabilizer. The purpose of this study is to analyse the problems of the soft stabilization in spinal instability. We reviewed 145 cases which were operative treatment using the Graf instrument for lumbar spinal disorder associated with posterior instability at our department from May, 1991 to Dec, 1995. The mean follow up periods was 29 months ranging from 24 months to 6 years 8 months. Of the 145 cases, 22 cases were showed the problem. The diagnostic method were simple x-ray, flexion-extension lateral stress view and CT scan. Results were as follows: Adjacent segmental instability was 10 cases(6.9%), disc space narrowing was 8 cases(5.5%), screw loosening was 3 cases(2.1%) and breakage of the Graf band was 1 case(0.6%). The problems of the soft stabilization were adjacent segmental instability, disc space narrowing, screw loosening, and breakage of the Graf band. But the rate of adjacent segmental instability and disc space narrowing was lower than other lumbar spinal instrumentation.

• Journal of Korean Neurosurgical Society
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• v.47 no.4
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• pp.265-270
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• 2010

Objective : The purpose of this study is to identify the relationship between asymptomatic urinary tract infection (aUTI) and postoperative spine infection. Methods : A retrospective review was done in 355 women more than 65 years old who had undergone laminectomy and/or discectomy, and spinal fusion, between January 2004 and December 2008. Previously postulated risk factors (i.e., instrumentation, diabetes, prior corticosteroid therapy, previous spinal surgery, and smoking) were investigated. Furthermore, we added aUTI that was not previously considered. Results : Among 355 patients, 42 met the criteria for aUTI (Bacteriuria ${\geq}\;10^5\;CFU/mL$ and no associated symptoms). A postoperative spine infection was evident in 15 of 355 patients. Of the previously described risk factors, multi-levels (p<0.05), instrumentation (p<0.05) and diabetes (p<0.05) were proven risk factors, whereas aUTI (p>0.05) was not statistically significant. However, aUTI with Foley catheterization was statistically significant when Foley catheterization was added as a variable to the all existing risk factors. Conclusion : aUTI is not rare in elderly women admitted to the hospital for lumbar spine surgery. The results of this study suggest that aUTI with Foley catheterization may be considered a risk factor for postoperative spine infection in elderly women. Therefore, we would consider treating aUTI before operating on elderly women who will need Foley catheterization.

• Journal of Biomedical Engineering Research
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• v.22 no.3
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• pp.249-257
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• 2001

The voluntary contracted EMG signal of spinal cord injured patients is very small because the information from central nervous system is not sufficiently transmitted to $\alpha$ motor neuron or muscle fiber. Therefore the acquisited EMG signal from needle or surface electrodes can not be identified obvious voluntary contraction pattern by muscle movement. In this paper we propose the extraction technique of voluntary muscle contraction and relaxation pattern from EMG signal of spinal cord injured patient whose EMG signal is composed of the linear sum of mo색 unit action potentials with two noise sources, additive noise assumed to be white Gaussian noise and high frequency discharge assumed to be not motor unit action potential but impulsive noise. In order to eliminate impulsive noise and additive noise from voluntary contracted EMG signal, we use the FatBear filter which is a nonarithmetic piecewise constant filter, and multiscale nonlinear wavelet denoising processing, respectively. The proposed technique is applied to the EMG signal acquisited from transverse myelitis patients to extract voluntary muscle contraction pattern.