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1.  The Use of Magnetic Resonance Imaging in Predicting the Clinical Outcome of Spinal Arteriovenous Fistula 
Yonsei Medical Journal  2015;56(2):397-402.
Magnetic resonance imaging (MRI) has been used to screen and follow-up spinal dural arteriovenous fistulae (SDAVF). The purpose of this study was to evaluate the association between MRI findings and neurologic function in SDAVF. This study also investigated clinical features and treatment results of SDAVF.
Materials and Methods
A total of 15 consecutive patients who underwent embolization or surgery for SDAVF were included. We treated seven (60%) patients with embolization and six (40%) with surgery. We analysed clinical features, MRI findings, treatment results, and neurologic function. Neurologic function was measured by the Aminoff-Logue disability scale (ALS).
Patients with longer levels of intramedullary high signal intensity in preoperative T2-weighted images (T2WI) exhibited worse pre- and postoperative ALS scores (r=0.557, p=0.031; r=0.530, p=0.042, Pearson correlation). Preoperative ALS score was significantly correlated with postoperative ALS score (r=0.908, p=0.000, Pearson correlation). The number of levels showing intramedullary high signal intensity in T2WI decreased significantly postoperatively (5.2±3.1 vs. 1.0±1.4, p=0.001, Wilcoxon ranked test).
The number of involved levels of high signal intensity in preoperative T2WI is useful for predicting pre- and postoperative neurologic function in SDAVF.
PMCID: PMC4329350  PMID: 25683987
Spine; dural arteriovenous fistula; magnetic resonance imaging; neurologic manifestations
2.  Rosai-Dorfman Disease in Thoracic Spine: A Rare Case of Compression Fracture 
Korean Journal of Spine  2014;11(3):198-201.
Sinus histiocytosis with massive lymphadenopathy known as Rosai-Dorfman disease is characterized by painless bilateral cervical lymphadenopathy. Extranodal manifestations are uncommon and spinal involvement is rare. A 15-year-old man presented with intermittent midthoracic back pain only. He had no specific findings on neurologic examinations, hematologic and biochemical laboratory tests. Radiological examination of thoracic spine revealed collapse of T6 vertebrae with thoracic kyphosis and osteolytic lesion of T12 vertebra body. He underwent a removal of bone tumor, anterior reconstruction with mesh and pedicle screw fixation via posterior approach for pathologic confirmation and stabilization. Histopathologic study of the lesion revealed focal infiltration of large histiocytes showing emperipolesis. Immunochemistry stain of histiocytes was positive for CD68 and S-100 but negative for CD1a. This report presents a rare case and literature review of extranodal Rosai-dorfman disease in thoracic spine.
PMCID: PMC4206961  PMID: 25346769
Rosai-Dorfman disease; Extranodal involvement; Thoracic vertebra; Compression fracture
3.  Correction of Coronal Imbalance in Degenerative Lumbar Spine Disease Following Direct Lateral Interbody Fusion (DLIF) 
Korean Journal of Spine  2012;9(3):176-180.
The authors have recently been using a surgical technique of minimally invasive direct lateral interbody fusion (DLIF) for correcting of coronal imbalance. The purpose of this study was to evaluate the surgical outcome and complication of DLIF.
We undertook retrospective analysis of a consecutive series of 8 DLIF procedures in Degenerative lumbar spine disease since May 2011. Four patients underwent DLIF only, and the others underwent combined DLIF and posterior fixation. Data on intra- and postoperative complications were collected. The pre- and postoperative X-rays were reviewed. We investigated coronal deformity, Cobb's angle, and apical vertebral translation (AVT). The mean follow-up period was months with a range of 2 to 8 months.
A mean preoperative coronal Cobb's angle was 21.8° (range 11.5-32.4°). Following after DLIF, the mean Cobb's angle was decreased to 13.0° (range 2.9-21.5°). Following additional posterior screw fixation, mean Cobb's angle was further decreased to 7.4° (range 2.9-13.2°). A mean preoperative AVT was 2.0 cm(range 0.6-3.5 cm), and improved to 1.4 cm(range 0.3-2.4 cm) and 0.8 cm(range 0.2-1.8 cm) postoperatively (DLIF and, posterior fixation respectively). One patient (12.5%) showed cage migration during follow-up period. Two patients (25%) developed motor weakness, and 4 patients (50%) experienced postoperative thigh paresthesias or dysesthesias. During follow up period, motor weakness had resolved in 1 patient. Sensory symptoms were improved in all patients at the last follow-up.
Degenerative lumbar disease can be effectively corrected by DLIF with acceptable complications.
PMCID: PMC4430998  PMID: 25983811
Degenerative lumbar disease; Coronal imbalance; DLIF; Lumbosacral plexus; Postoperative complication
4.  Initial Clinical Outcomes of Minimally Invasive Lateral Lumbar Interbody Fusion in Degenerative Lumbar Disease: A Preliminary Report on the Experience of a Single Institution with 30 Cases 
Korean Journal of Spine  2012;9(3):187-192.
The object of this study was to evaluate the clinical and radiological outcomes of minimally invasive lateral lumbar interbody fusion.
This study included 30 patients who underwent minimally invasive lateral lumbar interbody fusion at our hospital between May 2011 and February 2012 for the following diagnoses: degenerative disc disease, adjacent-segment degeneration, degenerative spondylolisthesis and lumbar degenerative scoliosis. Pain assessment was reported from 0 to 10 using a subjective visual analog scale (VAS) upon admission and at every follow-up day. Lumbar X-rays were obtained in the standing position upon admission and the 1st and 5th postoperative day, and at every follow-up day after the operation. The heights of the intervertebral disc space and neural foramen were measured using an electronic caliper with the PACS software. The surgical outcome was assessed as excellent, good, fair or poor using the Odom scale at the last follow-up.
The mean VAS for low back pain were 4.93±1.47 on admission and 2.01±1.35 at last follow-up, respectively, and for leg pain, the scores were 4.87±2.16 on admission and 1.58±1.52 at last follow-up. The mean height of intervertebral disc space increased by 34% (7.93±2.33 preoperatively, and 11.09±4.33 immediately after surgery, p<0.01). The mean height of neural foramen also increased by 6.4% without any statistical significance (19.17±2.84 preoperatively, and 20.49±4.50 immediately after the surgery). Minimally invasive lateral lumbar interbody fusion was successful in 27 patients (90%) at last follow-up. Surgical complications were reported as transient postoperative thigh sensory changes (5 patients, 16.7%), transient psoas muscle weakness (3 patients, 10%), cage migration (2 patients, 6.7%), lumbar plexus injury (1 patient, 3.3%), and pain aggravation (1 patient, 3.3%).
The minimally invasive lateral lumbar interbody fusion is a safe and effective procedure for treating degenerative lumbar disease with good outcomes and moderate complications. Further follow-up is necessary to establish its safety and efficacy.
PMCID: PMC4431000  PMID: 25983813
Spinal fusion; Treatment outcome; Complication
5.  Posterior Lumbar Interbody Fusion via a Unilateral Approach 
Yonsei Medical Journal  2006;47(3):319-325.
This study sought to determine the outcomes of posterior lumbar interbody fusion (PLIF), via a unilateral approach, in selected patients who presented with unilateral leg pain and segmental instability of the lumbar spine. Patients with a single level of a herniated disc disease in the lumbar spine, unilateral leg pain, chronic disabling lower back pain (LBP), and a failed conservative treatment, were considered for the procedure. A total of 41 patients underwent a single-level PLIF using two PEEK™ (Poly-Ether-Ether-Ketone) cages filled with iliac bone, via a unilateral approach. The patients comprised 21 women and 20 men with a mean age of 41 years (range: 22 to 63 years). Two cages were inserted using a unilateral medial facetectomy and a partial hemilaminectomy. At follow-up, the outcomes were assessed using the Prolo Scale. The success of the fusion was determined by dynamic lumbar radiography and/or computerized tomography scanning. All the patients safely underwent surgery without severe complications. During a mean follow-up period of 26 months, 1 patient underwent percutaneous pedicle screw fixation due to persistent LBP. A posterior displacement of the cage was found in one patient. At the last follow up, 90% of the patients demonstrated satisfactory results. An osseous fusion was present in 85% of the patients. A PLIF, via a unilateral approach, enables a solid union with satisfactory clinical results. This preserves part of the posterior elements of the lumbar spine in selected patients with single level instability and unilateral leg pain.
PMCID: PMC2688150  PMID: 16807980
Posterior lumbar interbody fusion (PLIF); unilateral approach; instability
6.  Efficacy and Safety of Sodium Hyaluronate with 1,4-Butanediol Diglycidyl Ether Compared to Sodium Carboxymethylcellulose in Preventing Adhesion Formation after Lumbar Discectomy 
Korean Journal of Spine  2015;12(2):41-47.
Epidural injection of hyaluronic acid may prevent adhesion formation after spine surgery, but the compounds used to stabilize hyaluronidase could interfere with its anti-adhesion effects. The present study was conducted as a clinical trial to evaluate the efficacy and safety of an experimental medical gel in preventing adhesion formation.
This study was designed as a multicenter, randomized, double-blind, and comparative controlled clinical trial with an observation period of 6 weeks. Subjects were randomly assigned into two groups: group A with sodium hyaluronate + 1,4-butanediol diglycidyl ether (BDDE) and group B with sodium hyaluronate + sodium carboxymethylcellulose (CMC). Visual analogue scale (VAS) of back and leg pain and the Oswestry disability index (ODI) and scar score ratings were assessed after surgery.
Mean scar grade was 2.37±1.13 in group A and 2.75±0.97 in group B, a statistically significant difference (p=0.012). VAS of back and leg pain and ODI scores decreased significantly from baseline to 3 and 6 weeks postoperatively in both groups (p<0.001). However, VAS and ODI scores were not statistically different between groups A and B at baseline or at 3 and 6 weeks after operation (p>0.3). The number of adverse reactions related to the anti-adhesion gels was not statistically different (p=0.569), but subsequent analysis of nervous adverse reactions showed group B was superior with a statistically difference (p=0.027).
Sodium hyaluronate with BDDE demonstrated similar anti-adhesion properties to sodium hyaluronate with CMC. But, care should be used to nervous adverse reactions by using sodium hyaluronate with BDDE.
PMCID: PMC4513167  PMID: 26217381
Anti-adhesion; Scar formation; Lumbar discectomy; Sodium hyaluronate; 1,4-butanediol diglycidyl ether (BDDE); Sodium carboxymethylcellulose (CMC)
7.  Efficacy of Percutaneous Epidural Neuroplasty Does Not Correlate with Dural Sac Cross-Sectional Area in Single Level Disc Disease 
Yonsei Medical Journal  2015;56(3):691-697.
Percutaneous epidural neuroplasty (PEN) is a minimally invasive treatment. The efficacy of PEN has been relatively well investigated; however, the relationship between the clinical effectiveness of PEN and the severity of spinal canal stenosis by disc material has not yet been established. The purpose of this study was to compare clinical outcomes of PEN according to the dural sac cross-sectional area in single level disc disease.
Materials and Methods
This study included 363 patients with back pain from single level disc disease with and without radiculopathy. Patients were categorized into groups according to spinal canal compromise by disc material: Category 1, less or more than 50%; and Category 2, three subgroups with lesser than a third, between a third and two thirds, and more than two thirds. Clinical outcomes were assessed according to the Visual Analog Scale (VAS) score for back pain and leg pain and Odom's criteria at 1, 3, 6, 12, and 24 months after treatment.
The demographic data showed no difference between groups according to spinal canal compromise by disc material except age (older age correlated with more spinal canal compromise). The dural sac cross-sectional area did not correlate with the VAS scores for back and leg pain after PEN in single level disc disease in Groups 1 and 2. Odom's criteria after PEN were also not different according to dural sac cross-sectional area by disc material.
PEN is an effective procedure in treating single level lumbar disc herniation without affecting dural sac cross-sectional area.
PMCID: PMC4397438  PMID: 25837174
Lower back pain; lumbar disc disease; percutaneous epidural neuroplasty; percutaneous adhesiolysis; dural sac cross-sectional area
8.  Feasibility of Translaminar Screw Placement in Korean Population: Morphometric Analysis of Cervical Spine 
Yonsei Medical Journal  2014;56(1):159-166.
To analyze the feasibility of unilateral and bilateral translaminar screw placement in Koran population, and compare the acceptance rate using previously reported data in American population.
Materials and Methods
The translaminar lengths, thickness, heights, and sagittal-diagonal measurements were performed. The feasibility analysis was performed using unilateral and bilateral 3.5 mm cervical screw placement on the CT scans within 0.5 mm of safety margin. We also performed radiographic analysis of the morphometric dimensions and the feasibility of unilateral and bilateral translaminar screw placement at C3-C7.
Korean population had similar or significantly shorter translaminar lengths and thickness (lengths and thickness in C7 among males; lengths in C6-C7 and thickness in C4 among females) than American population, but had similar or significantly longer translaminar heights and sagittal-diagonal measurements (heights in C3-C7 and sagittal-diagonal measurements in C3-C6 among males; heights in C7 and sagittal-diagonal measurements in C3-C7 among females). Unilaterally, translaminar screw acceptance rates in C3-C7 were similar between Korean and American male population, but the rates in C4-C6 were significantly smaller between Korean and American female population. Bilaterally, translaminar screw acceptance rates in C3 and C5-C6 were significantly larger between Korean and American male population, but the rates in C3-C7 were similar between Korean and American female population.
The feasibility of unilateral and bilateral translaminar screw placement is different depending on different ethnics. Subaxial cervical unilateral translaminar screw placement among Korean male population and bilateral placement at C4-C7 among Korean female population are more acceptable than American population.
PMCID: PMC4276750  PMID: 25510760
Translaminar; cervical fusion; cervical spine; ethics; Korean; American
9.  Biologic Response of Degenerative Living Human Nucleus Pulposus Cells to Treatment with Cytokines 
Yonsei Medical Journal  2014;56(1):277-286.
To investigate the molecular responses of various genes and proteins related to disc degeneration upon treatment with cytokines that affect disc-cell proliferation and phenotype in living human intervertebral discs (IVDs). Responsiveness to these cytokines according to the degree of disc degeneration was also evaluated.
Materials and Methods
The disc specimens were classified into two groups: group 1 (6 patients) showed mild degeneration of IVDs and group 2 (6 patients) exhibited severe degeneration of IVDs. Gene expression was analyzed after treatment with four cytokines: recombinant human bone morphogenic protein (rhBMP-2), transforming growth factor-β (TGF-β), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α). Molecular responses were assessed after exposure of cells from the IVD specimens to these cytokines via real-time polymerase chain reaction and immunofluorescence staining.
mRNA gene expression was significantly greater for aggrecan, type I collagen, type II collagen, alkaline phosphatase, osteocalcin, and Sox9 in group 1 than mRNA gene expression in group 2, when the samples were not treated with cytokines. Analysis of mRNA levels for these molecules after morphogen treatment revealed significant increases in both groups, which were much higher in group 1 than in group 2. The average number of IVD cells that were immunofluorescence stained positive for alkaline phosphatase increased after treatment with rhBMP-2 and TGF-β in group 1.
The biologic responsiveness to treatment of rhBMP-2, TGF-β, TNF-α, and IL-1β in the degenerative living human IVD can be different according to the degree of degeneration of the IVD.
PMCID: PMC4276767  PMID: 25510775
Cytokine; disc degeneration; rhBMP-2; TGF-β; TNF-α; IL-1β
10.  Surgical Outcomes after Traumatic Vertebral Fractures in Patients with Ankylosing Spondylitis 
Ankylosing spondylitis is an inflammatory rheumatic disease mainly affecting the axial skeleton. The rigid spine may secondarily develop osteoporosis, further increasing the risk of spinal fracture. In this study, we reviewed fractures in patients with ankylosing spondylitis that had been clinically diagnosed to better define the mechanism of injury, associated neurological deficit, predisposing factors, and management strategies.
Between January 2003 and December 2013, 12 patients with 13 fractures with neurological complications were treated. Neuroimaging evaluation was obtained in all patients by using plain radiography, CT scan, and MR imaging. The ASIA Impairment Scale was used in order to evaluate the neurologic status of the patients. Management was based on the presence or absence of spinal instability.
A total of 9 cervical and 4 thoracolumbar fractures were identified in a review of patients in whom ankylosing spondylitis had been diagnosed. Of these, 7 fractures were associated with a hyperextension mechanism. 10 cases resulted in a fracture by minor trauma. Posttraumatic neurological deficits were demonstrated in 11 cases and neurological improvement after surgery was observed in 5 of these cases.
Patients with ankylosing spondylitis are highly susceptible to spinal fracture and spinal cord injury even after only mild trauma. Initial CT or MR imaging of the whole spine is recommended even if the patient's symptoms are mild. The patient should also have early surgical stabilization to correct spinal deformity and avoid worsening of the patient's neurological status.
PMCID: PMC4200357  PMID: 25328647
Ankylosing spondylitis; Trauma; Vertebral fracture; Spinal cord injury; Surgery
11.  Spinal Cord Hemangioblastomas in von Hippel-Lindau Disease: Management of Asymptomatic and Symptomatic Tumors 
Yonsei Medical Journal  2012;53(6):1073-1080.
Standard treatment of asymptomatic spinal cord hemangioblastoma in von Hippel-Lindau (VHL) disease has yet to be established. The purpose of this study was to propose guidelines for the treatment of asymptomatic spinal cord hemangioblastomas in VHL disease.
Materials and Methods
VHL disease patients treated for spinal cord hemangioblastomas between 1999 and 2009 were included. All spinal cord hemangioblastomas were divided into three groups: Group 1, asymptomatic tumors at initial diagnosis followed with serial imaging studies; Group 2, asymptomatic tumors at initial diagnosis that were subsequently resected; and Group 3, symptomatic tumors at initial diagnosis, all of which were resected.
We identified 24 spinal cord hemangioblastomas in 12 patients. Groups 1, 2 and 3 comprised 13, 4 and 7 tumors, respectively. Group 1 exhibited a smaller tumor volume (257.1 mm3) and syrinx size (0.8 vertebral columns) than those of Group 2 (1304.5 mm3, 3.3 vertebral columns) and Group 3 (1787.4 mm3, 6.1 vertebral columns). No difference in tumor volume or syrinx size was observed between Groups 2 and 3. Five tumors in Group 1 were resected during follow-up because symptoms had developed or the tumor had significantly grown. Finally, among 17 asymptomatic tumors at the initial diagnosis, nine tumors were resected. Only one tumor of these nine tumors resulted in neurological deficits, while five of seven symptomatic tumors caused neurological deficits.
Selective resection of asymptomatic tumors before they cause neurological deficits might bring about better outcomes.
PMCID: PMC3481394  PMID: 23074104
Hemangioblastoma; spinal cord; treatment planning; von Hippel-Lindau disease
12.  Robot-Assisted Transoral Odontoidectomy : Experiment in New Minimally Invasive Technology, a Cadaveric Study 
In the field of spinal surgery, a few laboratory results or clinical cases about robotic spinal surgery have been reported. In vivo trials and development of related surgical instruments for spinal surgery are required before its clinical application. We investigated the use of the da Vinci® Surgical System in spinal surgery at the craniovertebral junction in a human cadaver to demonstrate the efficacy and pitfalls of robotic surgery.
Dissection of pharyngeal wall to the exposure of C1 and odontoid process was performed with full robotic procedure. Although assistance of another surgeon was necessary for drilling and removal of odontoid process due to the lack of appropriate end-effectors, successful robotic procedures for dural sutures and exposing spinal cord proved its safety and dexterity.
Robot-assisted odontoidectomy was successfully performed in a human cadaver using the da Vinci® Surgical System with few robotic arm collisions and minimal soft tissue damages. Da Vinci® Surgical System manifested more dexterous movement than human hands in the deep and narrow oral cavity. Furthermore, sutures with robotic procedure in the oral cavity demonstrated the advantage over conventional procedure.
Presenting cadaveric study proved the probability of robot-assisted transoral approach. However, the development of robotic instruments specific to spinal surgery must first precede its clinical application.
PMCID: PMC3098433  PMID: 21607188
Cervical; Robotics; Odontoid process; Craniovertebral junction; Transoral surgery
13.  Robot-assisted Resection of Paraspinal Schwannoma 
Journal of Korean Medical Science  2010;26(1):150-153.
Resection of retroperitoneal tumors is usually perfomed using the anterior retroperitoneal approach. Our report presents an innovative method utilizing a robotic surgical system. A 50-yr-old male patient visited our hospital due to a known paravertebral mass. Magnetic resonance imaging showed a well-encapsulated mass slightly abutting the abdominal aorta and left psoas muscle at the L4-L5 level. The tumor seemed to be originated from the prevertebral sympathetic plexus or lumbosacral trunk and contained traversing vessels around the tumor capsule. A full-time robotic transperitoneal tumor resection was performed. Three trocars were used for the robotic camera and working arms. The da Vinci Surgical System® provided delicate dissection in the small space and the tumor was completely removed without damage to the surrounding organs and great vessels. This case demonstrates the feasibility of robotic resection in retroperitoneal space. Robotic surgery offered less invasiveness in contrast to conventional open surgery.
PMCID: PMC3012842  PMID: 21218046
Paraspinal; Neurilemmoma; Robotic; Retroperitoneal Space
14.  Spinal Cord Tumors of the Thoracolumbar Junction Requiring Surgery: A Retrospective Review of Clinical Features and Surgical Outcome 
Yonsei Medical Journal  2007;48(6):988-993.
A retrospective review of medical records and imaging studies. To investigate characteristic clinical features and surgical outcomes of spinal cord tumors (SCTs) of the thoracolumbar junction (TLJ). The spinal cord transitions to the cauda equina in the TLJ. The TLJ contains the upper and lower motor neurons of the spinal cord and cauda equina. As a result, the clinical features of lesions in the TLJ vary, and these anatomical characteristics may affect surgical outcome.
Materials and Methods
Pathological diagnosis, clinical features, neurological signs, and surgical outcomes were investigated in 76 patients surgically treated at our institute for SCTs arising from T11 to L2. The patients were divided into epiconus (T11-12, n = 18) and conus groups (L1-2, n = 58).
Patients in the epiconus group had hyperactive deep tendon reflexes (DTRs), while those in the conus group had hypoactive DTRs (p < 0.05). Nine patients were misdiagnosed with intervertebral disc diseases (IVDs) before correct diagnoses were made. It was impossible to definitively determine the exact cause of symptoms in four patients who had both SCTs and IVDs.
Among SCTs of the TLJ, the epiconus group displayed upper motor neuron syndrome and the conus group displayed lower motor neuron syndrome. SCTs of the TLJ were frequently misdiagnosed as IVDs due to symptomatic similarities. SCTs of the TLJ should be included in differential diagnosis of back and leg pain, and it is highly recommended that routine lumbar magnetic resonance imaging include the TLJ.
PMCID: PMC2628177  PMID: 18159591
Spinal cord neoplasms; thoracolumbar junction; conus medullaris; cauda equina
15.  Early Clinical Experience with the Mobi-C Disc Prosthesis 
Yonsei Medical Journal  2007;48(3):457-464.
We have experienced 23 patients who had underwent cervical disc replacement with Mobi-C disc prosthesis and analyzed their radiological results to evaluate its efficacy.
Patients and Methods
This study was performed on 23 patients with degenerative cervical disc disease who underwent CDR with Mobi-C disc prosthesis from March 2006 to June 2006.
The age of the study population ranged from 31 to 62 years with mean of 43 years, and 16 male and 7 female cases. Regarding axial pain, the average preoperative VAS score was 6.47 ± 1.4, while at final follow-up it was 1.4 ± 0.7 (p < 0.001). The preoperatively VAS score for radiculopathy was 6.7 ± 0.7 compared with an average score of 0 ± 0 at the final follow-up (p < 0.001). At postoperative 6th month, Odom's criteria were excellent, good, or fair for all 23 patients (100%). 7 patients (30.4%) were classified as excellent, 15 patients (65.2%) as good, and 1 patients (4.4%) as fair. Prolo economic and functional rating scale was average 8.9 ± 0.7 at postoperative 6th month. ROM in C2-7, ROM of FSU, and ROM in upper adjacent level were well preserved after CDR.
This report would be the first document about the CDR with Mobi-C disc prosthesis in the treatment of degenerative cervical disc disease. CDR with Mobi-C disc prosthesis provided a favorable clinical and radiological outcome in this study. However, Long-term follow-up studies are required to prove its efficacy and ability to prevent adjacent segment disease.
PMCID: PMC2628079  PMID: 17594154
Cervical; arthroplasty; Mobi-C disc prosthesis
16.  Early Results from Posterior Cervical Fusion with a Screw-Rod System 
Yonsei Medical Journal  2007;48(3):440-448.
We performed 65 cases of posterior fusion surgery for cervical and/or high thoracic lesions using a polyaxial screw-rod system.
Patients and Methods
A total of 486 screws were implanted in 65 patients.
Fixation of the screws was carried out over an average of 2.9 spinal segments. Upon evaluation by postoperative CT scans, twelve (2.5%) screws had suboptimal trajectories but two of these revealed radiculopathy in one patient and required screw repositioning. No vascular sequelae resulted. There has been no segmental motion in any of the cases to date. As for other complications, there was one case of dural tearing and two cases of lateral mass fractures. There were no infections or other wound healing problems or hardware failures. No patients had neurological deterioration after surgery. There were statistically significant improvements in the mean Neck Disability Index (NDI) scores and Visual Analogue Scale (VAS) scores in the preoperative and late postoperative follow-up evaluations. Although further studies are required to establish the long-term results of fusion rates and clinical outcomes.
We cautiously suggest that the posterior polyaxial screw-rod system can be safely used as a primary or additional fusion method in this risky region. The successful and safe use of this method is dependent on a precise preoperative surgical plan and tactics for ensuring safe screw fixation.
PMCID: PMC2628078  PMID: 17594152
Cervical; thoracic; fixation; posterior fusion; screw-rod system
17.  Postoperative Spinal Epidural Hematoma: Risk Factor and Clinical Outcome 
Yonsei Medical Journal  2006;47(3):326-332.
We report a series of epidural hematomas which cause neurologic deterioration after spinal surgery, and have taken risk factors and prognostic factors into consideration. We retrospectively reviewed the database of 3720 cases of spine operation in a single institute over 7 years (1998 April-2005 July). Nine patients who demonstrated neurologic deterioration after surgery and required surgical decompression were identified. Factors postulated to increase the postoperative epidural hematoma and to improve neurologic outcome were investigated. The incidence of postoperative epidural hematoma was 0.24%. Operation sites were cervical 3 cases, thoracic 2 cases, and lumbar 4 cases. Their original diagnoses were tumor 3 cases, cervical stenosis 2 cases, lumbar stenosis 3 cases and herniated lumbar disc 1case. The symptoms of epidural hematomas were neurologic deterioration and pain. After decompression, clinical outcome revealed complete recovery in 3 cases (33.3%), incomplete recovery in 5 cases (55.6%) and no change in 1 case (11.1%). Factors increasing the risk of postoperative epidural hematoma were coagulopathy from medical illness or anticoagulation therapy (4 cases, 44.4%) and highly vascularized tumor (3 cases, 33.3%). The time interval to evacuation of complete recovery group (29.3 hours) was shorter than incomplete recovery group (66.3 hours). Patients with coagulopathy and highly vascularized tumor were more vulnerable to spinal epidural hematoma. The postoperative outcome was related to the preoperative neurological deficit and the time interval to the decompression.
PMCID: PMC2688151  PMID: 16807981
Clinical outcome; risk factor; postoperative; spinal epidural hematoma; spine surgery
18.  Real-time CT Fluoroscopy (CTF)-Guided Vertebroplasty in Osteoporotic Spine Fractures 
Yonsei Medical Journal  2005;46(5):635-642.
The purpose of this study was to evaluate the clinical feasibility, benefits, and limitations of CT fluoroscopy (CTF)-guided percutaneous vertebroplasty (PVP). PVP under the guidance of CTF without additional guidance by conventional C-arm fluoroscopy was performed in a total of 29 vertebral bodies in 21 patients with vertebral compression fractures. While monitoring sectional CTF images, the needle was advanced from the skin to the target vertebra. Contrast media and polymethylmethacrylate (PMMA) were injected into the target vertebra with careful monitoring of their distribution. After the procedure, an evaluation was conducted to determine whether extraosseous leakage of PMMA occurred and whether sufficient filling of PMMA had been achieved. Needle placement into the target vertebra was easily achieved with both the transpedicular and posterolateral approaches. Injection of PMMA and venous leakage of contrast media were carefully monitored in all patients, and early detection of PMMA leaking was achieved in 5 patients. Extraosseous leakage that had not been detected during the procedure was not found upon postoperative evaluation. Pain scales were significantly decreased after the procedure, and no obvious complications occurred following the procedure. CTF-guided PVP without the combined use of C-arm fluoroscopy was feasible and showed definite benefits. We believe that, in spite of some limitations, CTF-guided PVP provides an alternative technique appropriate in certain situations.
PMCID: PMC2810568  PMID: 16259060
Compression fracture; osteoporosis; vertebroplasty; CT fluoroscopy

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