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1.  At Least One Cyclic Teriparatide Administration Can Be Helpful to Delay Initial Onset of a New Osteoporotic Vertebral Compression Fracture 
Yonsei Medical Journal  2014;55(6):1576-1583.
Purpose
Teriparatide markedly increases bone formation and strength, while reducing the incidence of new-onset osteoporotic vertebral compression fractures (OVCFs). In some countries, expenses for teriparatide use are covered by medical insurance for up to 6 months; however, the national medical insurance of the authors' country does not cover these expenses. This retrospective cohort study compared the therapeutic effects of teriparatide on the initial onset of a new OVCF after treatment of osteoporosis and/or related OVCFs with regard to therapeutic durations of longer than 3 months (LT3M) or shorter than 3 months (ST3M).
Materials and Methods
From May 2007 to February 2012, 404 patients who were prescribed and administered teriparatide and who could be followed-up for longer than 12 months were enrolled. They were divided into two groups depending on teriparatide duration: LT3M (n=132) and ST3M (n=272).
Results
The group with the teriparatide duration of LT3M showed significantly less development of an initial OVCF within 1 year (p=0.004, chi-square). Duration of teriparatide use, body mass index, pre-teriparatide lowest spinal bone mineral density, and severity of osteoporosis significantly affected multiple regression analysis results (p<0.05). Survival analysis of first new-onset OVCFs demonstrated a significantly better survival rate for the LT3M group (log rank, p=0.005). Also, the ST3M group showed a higher odds ratio of 54.00 for development of an initial OVCF during follow-up than the LT3M group (Mantel-Haenzel common odds ratio, p=0.006).
Conclusion
At least one cyclic teriparatide administration is recommended to provide a protective effect against the initial onset of a new OVCF for up to one year after therapy.
doi:10.3349/ymj.2014.55.6.1576
PMCID: PMC4205697  PMID: 25323894
Osteoporosis; teriparatide; duration; vertebral compression fracture
2.  Sagittal Plane Analysis of Adolescent Idiopathic Scoliosis after VATS (Video-Assisted Thoracoscopic Surgery) Anterior Instrumentations 
Yonsei Medical Journal  2007;48(1):90-96.
Radiographic sagittal plane analysis of VATS (video-assisted thoracoscopic surgery) anterior instrumentation for adolescent idiopathic scoliosis. This is retrospective study. To report, in details about effects of VATS anterior instrumentation on the sagittal plane. Evaluations of the surgical outcome of scoliosis have primarily studied in coronal plane correction, functional, and cosmetic aspects. Sagittal balance, as well as coronal balance, is important in functional spine. Recently, scoliosis surgery applying VATS has been increasingly performed. Its outcome has been reported several times; however, according to our search of the literature, the only one study partially mentioned. The study population was a total of 42 cases of idiopathic scoliosis patients (8 male, 34 female). Their mean age was 15.6 years (13 to 18 years). The 18 cases were Lenke IA type, 16 cases were Lenke IB type, and 8 cases were Lenke IC type. The preoperative Cobb's angle was 54.5 ± 13.9°. All patients were followed up for a minimum of 2 years and implanted, on average, at the 5.9 level (5 to 8 levels). The most proximal implant was the 4th thoracic spine, and the most distal implant was the 1st lumbar spine. Whole spine standing PA and lateral radiographs were taken before surgery, 2 months after surgery, and at the last follow up (range 24-48 months, mean 35 months). The C7 plumbline proximal junctional measurement (PJM), distal junctional measurement (DJM), thoracic kyphosis, and lumbar lordosis angles were measured and compared. In all cases, follow-ups were possible and survived till the last follow up. The Cobb's angle in coronal plane at the last follow up was 19.7 ± 9.3° and was corrected to 63.8% on average. The preoperative C7 sagittal plumbline before surgery was -13.9 ± 29.1 mm, the final follow up was -9.9 ± 23.8 mm, and the average positive displacement was 4 mm. Thoracic kyphosis was increased from preoperative 18.2 ± 7.7° to 22.4 ± 7.2° on average at the last follow up, and the increase was, on average, 4.2°. The PJM angel was increased from 6.2 ± 4.3° preoperative to 8.8 ± 3.7° at the last follow up, and the increment was, on the average, 2.6°. The DJM angle before surgery was 6.8 ± 5.1° and 6.7 ± 4° at the last follow up, and did not change noticeably. Preoperative lumbar lordosis was 42 ± 10.7° and 43.5 ± 11.1° after surgery. Similarly, it did not change greatly. The scoliosis surgery applying VATS displaced the C7 sagittal plumb line by 4 mm to the anteriorly, increased thoracic kyphosis by 4.2°, and increased PJM by 2.6°. DJM and lumbar lordosis, before and after operation, were not significantly different. Although the surgical technique of VATS thoracic instrumentation is difficult to make the normal thoracic kyphosis, an acceptable sagittal balance can be obtained in Lenke type I adolescent idiopathic scoliosis using VATS.
doi:10.3349/ymj.2007.48.1.90
PMCID: PMC2627991  PMID: 17326250
Scoliosis; VATS; sagittal balance
3.  Transpedicular curettage and drainage versus combined anterior and posterior surgery in infectious spondylodiscitis 
Indian Journal of Orthopaedics  2014;48(1):74-80.
Background:
Hematogeneous infectious spondylodiscitis usually occurs in older immunocompromised patients with other comorbidities. They are usually unable to undergo reconstructive anterior and posterior surgeries. Therefore, an alternative, less aggressive surgical method of transpedicular curettage and drainage was suggested. This study was designed to compare the surgical outcomes for the treatment of hematogeneous infectious spondylodiscitis between transpedicular curettage and drainage technique and conventional combined anterior and posterior surgery.
Materials and Methods:
Between January 2002 and July 2011, 26 patients underwent surgical treatment for hematogeneous infectious spondylodiscitis. The patients were classified into two groups depending on surgical modality: a transpedicular curettage and drainage (TCD) group and a combined anterior and posterior surgery (CAPS) group.
Results:
The TCD group consisted of 10 patients (mean age 68.0 years), and the CAPS group consisted of 16 patients (mean age 58.4 years). The mean postoperative followup periods were 36.9 (months) in the TCD group and 69.9 (months) in the CAPS group. The operation time was 180.6 ± 33.6 minutes in the TCD group and 332.7 ± 74.5 minutes in the CAPS group (P < 0.05). Postoperative independent ambulation began at postoperative 4.9 ± 2.4 days in the TCD group but at postoperative 15.1 ± 15.3 days in the CAPS group (P < 0.05). The postoperative hospital stays were 19.9 ± 7.8 days in the TCD group and 35.4 ± 33.3 days in the CAPS group (P < 0.05). The level of C-reactive proteins decreased significantly in both groups after surgery (P < 0.05).
Conclusion:
Transpedicular curettage and drainage technique proved to be a useful technique for treating hematogeneous infectious spondylodiscitis in patients who were in poor heath with multiple comorbidities unable to undergo the conventional combined anterior and posterior surgery in a single day in terms of earlier ambulation, shorter hospitalization and similar clinical success rate.
doi:10.4103/0019-5413.125508
PMCID: PMC3931157  PMID: 24600067
Curettage; drainage; infectious; spondylodiscitis; transpedicular
4.  Cervical Foraminal and Discal Height after Dynamic Rotational Plating in the Cervical Discectomy and Fusion 
Asian Spine Journal  2013;7(4):289-293.
Study Design
This is a retrospective study.
Purpose
To evaluate the effect of the dynamic rotational plate to the intervertebral foraminal and discal height after anterior cervical discectomy and fusion.
Overview of Literature
There is no report regarding the changes of foraminal and discal height following cervical dynamic rotational plating.
Methods
We reviewed the outcomes of 30 patients (36 levels), who were followed-up for an average of 15 months (range, 12-57 months) after undergoing fusions with anterior cervical dynamic rotational plating for cervical radiculopathy, from March 2005 to February 2009. The changes of foraminal and intervertebral discal height of the operated levels were observed on oblique and lateral radiographs obtained at the preoperative, postoperative and follow-up examinations.
Results
The foraminal and discal height increased sufficiently, immediately following the operation. However, follow-up results showed gradual decrease in the foraminal and discal height. After 6 months of the surgery, they showed little difference compared with the preoperative heights. However, clinically, patients showed improvements in radiating pain during the follow-up period.
Conclusions
Anterior cervical dynamic rotational plating was an effective treatment modality for cervical radiculopathy without the deterioration of the foraminal and intervertebral discal height.
doi:10.4184/asj.2013.7.4.289
PMCID: PMC3863654  PMID: 24353845
Cervical spine; Cervical radiculopathy; Dynamic rotational plate
5.  Analysis of Single Nucleotide Polymorphism in Adolescent Idiopathic Scoliosis in Korea: For Personalized Treatment 
Yonsei Medical Journal  2013;54(2):500-509.
Purpose
The incidence of adolescent idiopathic scoliosis (AIS) has rapidly increased, and with it, physician consultations and expenditures (about one and a half times) in the last 5 years. Recent etiological studies reveal that AIS is a complex genetic disorder that results from the interaction of multiple gene loci and the environment. For personalized treatment of AIS, a tool that can accurately measure the progression of Cobb's angle would be of great use. Gene analysis utilizing single nucleotide polymorphism (SNP) has been developed as a diagnostic tool for use in Caucasians but not Koreans. Therefore, we attempted to reveal AIS-related genes and their relevance in Koreans, exploring the potential use of gene analysis as a diagnostic tool for personalized treatment of AIS therein.
Materials and Methods
A total of 68 Korean AIS and 35 age- and sex-matched, healthy adolescents were enrolled in this study and were examined for 10 candidate scoliosis gene SNPs.
Results
This study revealed that the SNPs of rs2449539 in lysosomal-associated transmembrane protein 4 beta (LAPTM4B) and rs5742612 in upstream and insulin-like growth factor 1 (IGF1) were associated with both susceptibility to and curve severity in AIS. The results suggested that both LAPTM4B and IGF1 genes were important in AIS predisposition and progression.
Conclusion
Thus, on the basis of this study, if more SNPs or candidate genes are studied in a larger population in Korea, personalized treatment of Korean AIS patients might become a possibility.
doi:10.3349/ymj.2013.54.2.500
PMCID: PMC3575984  PMID: 23364988
Adolescent idiopathic scoliosis; gene; single nucleotide polymorphism
6.  Stable Isolation of Phycocyanin from Spirulina platensis Associated with High-Pressure Extraction Process 
A method for stably purifying a functional dye, phycocyanin from Spirulina platensis was developed by a hexane extraction process combined with high pressure. This was necessary because this dye is known to be very unstable during normal extraction processes. The purification yield of this method was estimated as 10.2%, whose value is 3%–5% higher than is the case from another conventional separation method using phosphate buffer. The isolated phycocyanin from this process also showed the highest purity of 0.909 based on absorbance of 2.104 at 280 nm and 1.912 at 620 nm. Two subunits of phycocyanin namely α-phycocyanin (18.4 kDa) and β-phycocyanin (21.3 kDa) were found to remain from the original mixtures after being extracted, based on SDS-PAGE analysis, clearly demonstrating that this process can stably extract phycocyanin and is not affected by extraction solvent, temperature, etc. The stability of the extracted phycocyanin was also confirmed by comparing its DPPH (α,α-diphenyl-β-picrylhydrazyl) scavenging activity, showing 83% removal of oxygen free radicals. This activity was about 15% higher than that of commercially available standard phycocyanin, which implies that the combined extraction method can yield relatively intact chromoprotein through absence of degradation. The results were achieved because the low temperature and high pressure extraction effectively disrupted the cell membrane of Spirulina platensis and degraded less the polypeptide subunits of phycocyanin (which is a temperature/pH-sensitive chromoprotein) as well as increasing the extraction yield.
doi:10.3390/ijms14011778
PMCID: PMC3565347  PMID: 23325046
Spirulina platensis; phycocyanin; high-pressure extraction process
7.  Transpedicular Curettage and Drainage of Infective Lumbar Spondylodiscitis: Technique and Clinical Results 
Clinics in Orthopedic Surgery  2012;4(3):200-208.
Background
Infective spondylodiscitis usually occurs in patients of older age, immunocompromisation, co-morbidity, and individuals suffering from an overall poor general condition unable to undergo reconstructive anterior and posterior surgeries. Therefore, an alternative, less aggressive surgical method is needed for these select cases of infective spondylodiscitis. This retrospective clinical case series reports our novel surgical technique for the treatment of infective spondylodiscitis.
Methods
Between January 2005 and July 2011, among 48 patients who were diagnosed with pyogenic lumbar spondylodiscitis or tuberculosis lumbar spondylodiscitis, 10 patients (7 males and 3 females; 68 years and 48 to 78 years, respectively) underwent transpedicular curettage and drainage. The mean postoperative follow-up period was 29 months (range, 7 to 61 months). The pedicle screws were inserted to the adjacent healthy vertebrae in the usual manner. After insertion of pedicle screws, the drainage pedicle holes were made through pedicles of infected vertebra(e) in order to prevent possible seeding of infective emboli to the healthy vertebra, as the same instruments and utensils are used for both pedicle screws and the drainage holes. A minimum of 15,000 mL of sterilized normal saline was used for continuous irrigation through the pedicular pathways until the drained fluid looked clear.
Results
All patients' symptoms and inflammatory markers significantly improved clinically between postoperative 2 weeks and postoperative 3 months, and they were satisfied with their clinical results. Radiologically, all patients reached the spontaneous fusion between infected vertebrae and 3 patients had the screw pulled-out but they were clinically tolerable.
Conclusions
We suggest that our method of transpedicular curettage and drainage is a useful technique in regards to the treatment of infectious spondylodiscitic patients, who could not tolerate conventional combined anterior and posterior surgery due to multiple co-morbidities, multiple level infectious lesions and poor general condition.
doi:10.4055/cios.2012.4.3.200
PMCID: PMC3425650  PMID: 22949951
Spondylodiscitis; Curettage; Drainage; Surgery; Transpedicular
8.  Video-Assisted Thoracoscopic Surgery Plus Lumbar Mini-Open Surgery for Adolescent Idiopathic Scoliosis 
Yonsei Medical Journal  2010;52(1):130-136.
Purpose
The objectives of this study are to describe the outcome of adolescent idiopathic scoliosis (AIS) patients treated with Video Assisted Thoracoscopic Surgery (VATS) plus supplementary minimal incision in the lumbar region for thoracic and lumbar deformity correction and fusion.
Materials and Methods
This is a case series of 13 patients treated with VATS plus lumbar mini-open surgery for AIS. A total of 13 patients requiring fusions of both the thoracic and lumbar regions were included in this study: 5 of these patients were classified as Lenke type 1A and 8 as Lenke type 5C. Fusion was performed using VATS up to T12 or L1 vertebral level. Lower levels were accessed via a small mini-incision in the lumbar area to gain access to the lumbar spine via the retroperitoneal space. All patients had a minimum follow-up of 1 year.
Results
The average number of fused vertebrae was 7.1 levels. A significant correction in the Cobb angle was obtained at the final follow-up (p = 0.001). The instrumented segmental angle in the sagittal plane was relatively well-maintained following surgery, albeit with a slight increase. Scoliosis Research Society-22 (SRS-22) scores were noted have significantly improved at the final follow-up (p < 0.05).
Conclusion
Indications for the use of VATS may be extended from patients with localized thoracic scoliosis to those with thoracolumbar scoliosis. By utilizing a supplementary minimal incision in the lumbar region, a satisfactory deformity correction may be accomplished with minimal post-operative scarring.
doi:10.3349/ymj.2011.52.1.130
PMCID: PMC3017688  PMID: 21155045
Scoliosis; VATS; mini-open retroperitoneal approach
9.  Antibiotic Microbial Prophylaxis for Spinal Surgery: Comparison between 48 and 72-Hour AMP Protocols 
Asian Spine Journal  2010;4(2):71-76.
Study Design
This is a prospective randomized cohort study.
Purpose
We intended to evaluate the efficacy of a 48 hour antibiotic microbial prophylaxis (AMP) protocol as compared with a 72 hour AMP protocol.
Overview of Literature
The current guideline for the prevention of surgical site infection (SSI) suggests the AMP should not exceed 24 hours after clean surgery like spinal surgery. But there exist some confusion in real clinical practice about the duration of postoperative antibiotic administration because the evidence of the guideline was not robust.
Methods
The subjects were 548 patients who underwent spinal surgery at our department from April 2007 to December 2008. The patients were classified into two groups according to the prophylaxis protocol: group A, for which AMP was employed for 72 hours postoperatively and group B, for which AMP was employed for 48 hours postoperatively. Five hundred two patients out of 548 patients were followed until 6 months postoperatively. The incidence of SSI in the two groups was analyzed.
Results
The overall infection rate was 0.8%. There was no significant difference in infection rate between the two groups. The overall infection rate for the patients who underwent instrumented fusion was 0.9%. There was no significant difference in the infection rate between the patients of the two groups who underwent instrumented fusion.
Conclusions
AMP for 48 hours is as efficient as AMP for 72 hours.
doi:10.4184/asj.2010.4.2.71
PMCID: PMC2996630  PMID: 21165308
Spine; Surgical site infection; Anti-bacterial agents
10.  Comparison between Operated Muscular Dystrophy and Spinal Muscular Atrophy Patients in terms of Radiological, Pulmonary and Functional Outcomes 
Asian Spine Journal  2010;4(2):82-88.
Study Design
Retrospective comparative study.
Purpose
To study and compare the surgical outcomes of muscular dystrophy (MD) and spinal muscle atrophy (SMA).
Overview of Literature
There are few reports that have evaluated and compared the surgical outcomes of MD and SMA patients.
Methods
The patients (n = 35) were divided into two groups: a MD group with 24 patients and a SMA group with 11 patients. The average follow-up period was 21 months. All patients were operated for scoliosis correction using posterior instrumentation and fusion. In the immediate postoperative period, all efforts were made to reduce the pulmonary complications using non-invasive positive pressure ventilation and a coughing assist devices. The patients were evaluated by radiograph in terms of the Cobb's angle, pelvic obliquity, T1 translation, thoracic kyphosis and lumbar lordosis. The pulmonary function and self-image satisfaction were also assessed.
Results
There was a lower correction rate in the MD group (41.5%) than in the SMA group (48.3%), even though the curves were smaller in the MD group. The correction in the pelvic obliquity was significantly better in the SMA group (p = 0.03). The predicted vital capacity showed a 4% reduction in the MD group 1 year after surgery, while the SMA group showed a 10% reduction. The peak cough flow and end tidal PCO2 did not deteriorate and were well maintained. The average score for the improvement in self-image satisfaction postoperatively was 3.96 and 4.64 for the MD and SMA groups, respectively. The total complication rate was 45.7%; 14.3% of which were respiratory-related.
Conclusions
Surgical intervention for MD and SMA may be performed safely in patients with a very low forced vital capacity (< 30%) through aggressive preoperative and postoperative rehabilitation efforts.
doi:10.4184/asj.2010.4.2.82
PMCID: PMC2996632  PMID: 21165310
Muscular dystrophy; Spinal muscular atrophy; Neuromuscular scoliosis; Surgical correction; Pulmonary function
11.  Pulsed Electromagnetic Field Stimulates Cellular Proliferation in Human Intervertebral Disc Cells 
Yonsei Medical Journal  2010;51(6):954-959.
Purpose
The purpose of this study is to investigate the mechanism of cellular proliferation of electromagnetic field (EMF) on human intervertebral disc (IVD) cells.
Materials and Methods
Human IVD cells were cultured three-dimensionally in alginate beads. EMF was exposed to IVD cells with 650Ω, 1.8 millitesla magnetic flux density, 60 Hz sinusoidal wave. Cultures were divided into a control and EMF group. Cytotoxicity, DNA synthesis and proteoglycan synthesis were measured by MTT assay, [3H]-thymidine, and [35S]-sulfate incorporation. To detect phenotypical expression, reverse transcription-polymerase chain reactions (RT-PCR) were performed for aggrecan, collagen type I, and type II mRNA expression. To assess action mechanism of EMF, IVD cells were exposed to EMF with NG-Monomethyl-L-arginine (NMMA) and acetylsalicylic acid (ASA).
Results
There was no cytotoxicity in IVD cells with the EMF group in MTT assay. Cellular proliferation was observed in the EMF group (p < 0.05). There was no difference in newly synthesized proteoglycan normalized by DNA synthesis between the EMF group and the control. Cultures with EMF showed no significant change in the expression of aggrecan, type I, and type II collagen mRNA compared to the control group. Cultures with NMMA (blocker of nitric oxide) or ASA (blocker of prostaglandin E2) exposed to EMF demonstrated decreased DNA synthesis compared to control cultures without NMMA or ASA (p < 0.05).
Conclusion
EMF stimulated DNA synthesis in human IVD cells while no significant effect on proteoglycan synthesis and chondrogenic phenotype expressions. DNA synthesis was partially mediated by nitric oxide and prostaglandin E2. EMF can be utilized to stimulate proliferation of IVD cells, which may provide efficient cell amplification in cell therapy to degenerative disc disease.
doi:10.3349/ymj.2010.51.6.954
PMCID: PMC2995961  PMID: 20879066
Electromagnetic fields; intervertebral disc; nitric oxide; prostaglandin E2
12.  Video-Assisted Thoracoscopic Surgery for Correction of Adolescent Idiopatic Scoliosis: Comparison of 4.5 mm versus 5.5 mm Rod Constructs 
Yonsei Medical Journal  2010;51(5):753-760.
Purpose
The purpose of this study is to report the comparative results of thoracoscopic correction achieved via cantilever technique using a 4.5 mm thin rod and the poly-axial reduction screw technique using a 5.5 mm thick rod in Lenke type 1 adolescent idiopathic scoliosis (AIS).
Materials and Methods
Radiographic data, Scoliosis Research Society (SRS) patient-based outcome questionnaires, and operative records were reviewed for forty-nine patients undergoing surgical treatment of scoliosis. The study group was divided into a 4.5 mm thin rod group (n = 24) and a 5.5 mm thick rod group (n = 25). The radiographic parameters that were analyzed included coronal curve correction, the most caudal instrumented vertebra tilt angle correction, coronal balance, and thoracic kyphosis.
Results
The major curve was corrected from 49.8° and 47.2° pre-operatively to 24.5° and 18.8° at the final follow-up for the thin and thick rod groups, respectively (50.8% vs. 60.2% correction). There were no significant differences between the two groups in terms of kyphosis, coronal balance, or tilt angle at the time of the final follow-up. The mean number of levels fused was 6.2 in the thin rod group, compared with 5.9 levels in the thick rod group. There were no major intraoperative complications in either group.
Conclusion
Significant correction loss was observed in the thin rod system at the final follow-up though both groups had comparable correction immediately post-operative. Therefore, the thick rod with poly axial screw system helps to maintain post-operative correction.
doi:10.3349/ymj.2010.51.5.753
PMCID: PMC2908885  PMID: 20635452
Instrumentation; rod; scoliosis; thoracoscopic surgery
13.  Comparison of Surgical Outcomes in Thoracolumbar Fractures Operated with Posterior Constructs Having Varying Fixation Length with Selective Anterior Fusion 
Yonsei Medical Journal  2009;50(4):546-554.
Purpose
Surgical treatment in the case of thoracolumbar burst fractures is very controversial. Posterior instrumentation is most frequently used, however, but the number of levels to be instrumented still remains a matter of debate.
Materials and Methods
A total of 94 patients who had a single burst fracture between T11 and L2 were selected and were managed using posterior instrumentation with anterior fusion when necessary. They were divided into three groups as follows; Group I (n = 28) included patients who were operated by intermediate segment fixation, Group II (n = 32) included patients operated by long segment fixation, and Group III (n = 34) included those operated by intermediate segment fixation with a pair of additional screws in the fractured vertebra. The mean follow-up period was twenty one months. The outcomes were analyzed in terms of kyphosis angle (KA), regional kyphosis angle (RA), sagittal index (SI), anterior height compression rate, Frankel classification, and Oswestry Disability Index questionnaire.
Results
In Groups II and III, the correction values of KA, RA, and SI were much better than in Group I. At the final follow up, the correction values of KA (6.3 and 12.1, respectively) and SI (6.2 and 12.0, respectively) were in Groups II and III found to be better in the latter.
Conclusion
The intermediate segment fixation with an additional pair of screws at the fracture level vertebra gives results that are comparable or even better than long segment fixation and gives an advantage of preserving an extra mobile segment.
doi:10.3349/ymj.2009.50.4.546
PMCID: PMC2730618  PMID: 19718404
Thoracolumbar burst fracture; posterior instrumentation; intermediate segment fixation; fixation length; selective anterior fusion
14.  Risk Factors Associated with the Halo Phenomenon after Lumbar Fusion Surgery and its Clinical Significance 
Asian Spine Journal  2008;2(1):22-26.
Study Design
Retrospective study.
Purpose
First, to examine the association between bone mineral density (BMD) and the halo phenomenon, and second, to investigate risk factors predisposing to the halo phenomenon and its correlation with clinical outcomes.
Overview of Literature
The few in vivo studies regarding the relationship between pedicle screw stability and BMD have shown conflicting results.
Methods
Forty-four female patients who underwent spine fusion surgery due to spinal stenosis were included in this study. The halo phenomenon and fusion state were evaluated through plain radiographs performed immediately after surgery and through the final outpatient follow-up examination. BMD, osteoarthritis grade in the hip and knee joints, and surgical outcome were also evaluated.
Results
BMD was not related to the halo phenomenon, but age, absence of osteoarthritis in the knee, and non-union state were found to be significant risk factors for the halo phenomenon. However, the radiological halo phenomenon did not correlate with clinical outcome (visual analogue scale for back pain and leg pain).
Conclusions
The halo phenomenon is a simple phenomenon that can develop during follow-up after pedicle screw fixation. It does not influence clinical outcomes, and thus it is thought that hydroxyapatite coating screws, expandable screws, cement augmentation, and additional surgeries are not required, if their purpose is to prevent the halo phenomenon.
doi:10.4184/asj.2008.2.1.22
PMCID: PMC2857487  PMID: 20411138
Halo phenomenon; Pedicle screw; Bone mineral density
15.  Incidence and Risk Factors Associated with Superior Mesenteric Artery Syndrome following Surgical Correction of Scoliosis 
Asian Spine Journal  2008;2(1):27-33.
Study Design
Retrospective study.
Purpose
To more accurately determine the incidence and clarify risk factors.
Overview of Literature
Superior mesenteric artery syndrome is one of the possible complications following correctional operation for scoliosis. However, when preliminary symptoms are vague, the diagnosis of superior mesenteric artery syndrome may be easily missed.
Methods
We conducted a retrospective study using clinical data from 118 patients (43 men and 75 women) who underwent correctional operations for scoliosis between September 2001 and August 2007. The mean patient age was 15.9 years (range 9~24 years). The risk factors under scrutiny were the patient body mass index (BMI), change in Cobb's angle, and trunk length.
Results
The incidence of subjects confirmed to have obstruction was 2.5%. However, the rate increased to 7.6% with the inclusion of the 6 subjects who only showed clinical symptoms of obstruction without confirmative study. The BMI for the asymptomatic and symptomatic groups were 18.4±3.4 and 14.6±3, respectively. The change in Cobb's angle for the asymptomatic and symptomatic groups were 24.8±13.6° and 23.4±9.1°, respectively. The change in trunk length for the asymptomatic and symptomatic groups were 2.3±2.1 cm and 4.5±4.8 cm, respectively. Differences in Cobb's angle and the change in trunk length between the two groups did not reach statistical significance, although there was a greater increase in trunk length for the symptomatic group than for the asymptomatic group.
Conclusions
Our study shows that the incidence of superior mesenteric artery syndrome may be greater than the previously accepted rate of 4.7%. Therefore, in the face of any early signs or symptoms of superior mesenteric artery syndrome, prompt recognition and treatment are necessary.
doi:10.4184/asj.2008.2.1.27
PMCID: PMC2857491  PMID: 20411139
Scoliosis; Superior mesenteric artery syndrome; Body mass index; Trunk length
16.  Delayed Onset Neurological Deterioration due to a Spinal Epidural Hematoma after a Spine Fracture 
Asian Spine Journal  2007;1(2):98-101.
There are no reports of a 7-day delay in the onset of neurological deterioration because of a spinal epidural hematoma (SEH) after a spinal fracture. A hematoma was detected from the T12 to L2 area in a 36-year-old male patient with a T12 burst fracture. On the same day, the patient underwent in situ posterior pedicle instrumentation on T10-L3 with no additional laminectomy. On the seventh postoperative day, the patient suddenly developed weakness and sensory changes in both extremities, together with a sharp pain. A MRI showed that the hematoma had definitely increased in size. A partial laminectomy was performed 12 hours after the onset of symptoms. Two days after surgery, recovery of neurological function was noted. This case shows that spinal surgeons need to be aware of the possible occurrence of a delayed aggravated SEH and neurological deterioration after a spinal fracture.
doi:10.4184/asj.2007.1.2.98
PMCID: PMC2857477  PMID: 20411132
Spinal epidural hematoma; Spine fracture; Neurology
17.  The Incidence of New Vertebral Compression Fractures in Women after Kyphoplasty and Factors Involved 
Yonsei Medical Journal  2007;48(4):645-652.
Purpose
To identify the incidence of new vertebral compression fractures in women after kyphoplasty and to analyze influential factors in these patients.
Materials and Methods
One hundred and eleven consecutive female patients with osteoporotic vertebral compression fractures (VCFs) underwent kyphoplasty at 137 levels. These patients were followed for 15.2 months postoperatively. For the survey of new vertebral compression fractures, medical records and x-rays were reviewed, and telephone interviews were conducted with all patients.
Results
During that time 20 (18%) patients developed new VCFs. The rate of occurrence of new VCFs in one year was 15.5% using a Kaplan-Meier curve. Body mass index (BMI), symptom duration and kyphoplasty level were the statistically significant factors between the patient groups both with and without new VCFs after kyphoplasty. In the comparison between the adjacent and remote new VCF groups, the adjacent new VCF group showed a larger amount of polymethyl methacrylate (PMMA) use during kyphoplasty (p < 0.05). Before kyphoplasty, 9.9% of the patients had been prescribed medication for osteoporosis, and 93.7% of the patients started or continued medication after kyphoplasty. The development of new VCFs was affected by the number of vertebrae involved in the kyphoplasty. However, the lower incidence rate (15.5%) of new compression fractures might be due to a greater percentage (93.7% in our study) of patients taking anti-osteoporotic medication before and/or after kyphoplasty.
Conclusion
When kyphoplasty is planned for the management of patients with osteoporotic VCFs, the application of a small amount of PMMA can be considered in order to lower the risk of new fractures in adjacent vertebrae. The postoperative use of anti- osteoporotic medication is recommended for the prevention of new VCFs.
doi:10.3349/ymj.2007.48.4.645
PMCID: PMC2628047  PMID: 17722237
Kyphoplasty; compression fracture; influencing factor
18.  Comparison of the Predictive Value of Myelography, Computed Tomography and MRI on the Treadmill Test in Lumbar Spinal Stenosis 
Yonsei Medical Journal  2005;46(6):806-811.
To date, there have been no prospective, objective studies comparing the accuracy of the MRI, myelo-CT and myelography. The purpose of this study is to compare the diagnostic and predictive values of MRIs, myelo-CTs, and myelographies. Myelographies with dynamic motion views, myelo-CTs, MRIs and exercise treadmill tests were performed in 35 cases. The narrowest AP diameter of the dural sac was measured by myelography. At the pathologic level, dural cross-sectional area (D-CSA) was calculated in the MRI and Myelo-CT. The time to the first symptoms (TAF) and the total ambulation time (TAT) were measured during the exercise treadmill test and used as the standard in the comparison of correlation between radiographic parameters and walking capacity. The mean D-CSA by CT was 58.3 mm2 and 47.6 mm2 by MRI. All radiographic parameters such as AP diameters and D-CSA have no correlation to TAF or TAT (p>0.05). Our data showed no statistically significant differences in the correlation of the patients' walking capacity to the severity of stenosis as assessed by myelography, myelo-CT and MRI.
doi:10.3349/ymj.2005.46.6.806
PMCID: PMC2810595  PMID: 16385657
Spinal stenosis; myelography; spiral computed tomography; magnetic resonance imaging; exercise test; predictive value of tests

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