Discogenic differentiation of human bone marrow mesenchymal stem cell with adenovirus mediated glucose transporter-1 and hypoxia inducible factor-1α gene therapy

Dept. of Medicine/박사With aging and degeneration, intervertebral discs (IVDs) undergo profound and substantial changes in morphology and biochemical composition. An ideal solution for managing disc degeneration would be to repair the IVDs, by producing discogenic matrix. Recently, various approaches to biological repair of the disc function are under investigation, which are gene therapy, growth factor injection, cell therapy and cell-based tissue engineering. Hypoxia inducible factor-1α (HIF-1α) is the key molecules regulating energy metabolism and survival in the nucleus pulposus (NP) cell. The expression of HIF was demonstrated in the NP cell of normal human IVDs and can be used as a phenotypic marker of NP cell. Hypoxia responsive glucose transporter-1(GLUT-1) is a facilitative glucose transporter in the NP cell and also can be used as a phenotypic marker of NP cell along with HIF-1αThe discogenic induction from human bone marrow mesenchymal stem cell(BMSC) using adenoviral transduction of NP specific phenotypic factors of HIF-1α and GLUT-1 was investigated via in vitro and in vivo experiments. The BMSC was obtained from patients during surgery for lumbar spinal stenosis. Each control and experimental groups, in vitro and in vivo experiments were performed simultaneously. In vivo study, total of 6 conditions including 1 positive control with NP cell and 1 negative control with BMSC alone were set by the combination of control, viral vector and transducted genes. All groups were consisted of BMSC, BMSC with Ad-mock, the NP cell, BMSC with Ad-HIF-1α, BMSC with Ad-GLUT-1 and BMSC with Ad-HIF-1α and Ad-GLUT-1 in order. The gene transduction using adenovirus and subsequent differentiation of BMSC into NP cell was confirmed by reverse-transcription polymerase chain reaction(RT-PCR) and histologic analyses. In vivo experiment, xenograft of alginate-BMSC complex on the back of mice (DVA/1J) was done. Mice were sacrificed at 2 weeks and 4 weeks after subcutaneous implantation of alginate-BMSC complexes. Analyses of each specimen including histologic test were done. The mRNA of matrix component including aggrecan and collagen type II in the differentiated NP cell was tested. In vitro result at 24 and 48 hours culture, the BMSC with Ad-HIF-1α or Ad-GLUT-1 or both with Ad-HIF-1α and Ad-GLUT-1 groups showed increased mRNA expression of GLUT-1, aggrecan, and type II collagen compared to control and the expression level was comparable level of NP cell group. In HIF-1α mRNA expression, BMSC with Ad-HIF-1α, and the BMSC with Ad-HIF-1α and Ad-GLUT-1 groups showed increased level of expression of HIF-1α mRNA compared to those of other groups. Based on the different oxygen conditioned culture for 96 hours, expression of HIF-1α and GLUT-1 mRNA of normoxic-hypoxic group showed analogous pattern with that of continuous normoxic group. In matrix component mRNA expression, expression pattern of aggrecan and collagen type II mRNA was comparable with that of continuous hypoxic group.For in vivo study, the BMSC with Ad-HIF-1α, BMSC with Ad-GLUT-1 and BMSC with Ad-HIF-1α and Ad-GLUT-1 groups showed positive stains for collagen type II and aggrecan, which were analogous to the NP cell group. In conclusion, transduction of each gene of the HIF-1α, GLUT-1 using adenovirus vector was proved to be effective to induce the differentiation of BMSC into discogenic phenotype in vitro and in vivo.ope

Biomechanical Comparison of Multilevel Lumbar Instrumented Fusions in Adult Spinal Deformity According to the Upper and Lower Fusion Levels: A Finite Element Analysis

Multilevel lumbar fusion with posterior pedicle screw fixation is a widely performed surgical procedure for the management of adult spinal deformity. However, there has not been a comprehensive biomechanical study on the different types of fusion levels in terms of stability and possible complications. We aimed to investigate the biomechanical properties of multilevel lumbar fusion according to different types of upper and lower fusion levels. Six different types of fusions were performed using three-dimensional finite element models. Type A and B referred to the group of which upper fusion level was L1 and T10, respectively. Subtype 1, 2, and 3 referred to the group of which lower fusion level was L5, S1, and ilium, respectively (A1, L1-L5; A2, L1-S1; A3, L1-ilium; B1, T10-L5; B2, T10-S1; B3, T10-ilium). Flexion, extension, axial rotation, and lateral bending moments were applied, and the risk of screw loosening and failure and adjacent segment degeneration (ASD) was analyzed. Stress at the bone-screw interface of type B3 was lowest in overall motions. The risk of screw failure showed increasing pattern as the upper and lower levels extended in all motions. Proximal range of motion (ROM) increased as the lower fusion level changed from L5 to S1 and the ilium. For axial rotation, type B3 showed higher proximal ROM (16.2°) than type A3 (11.8°). In multilevel lumbar fusion surgery for adult spinal deformity, adding iliac screws and increasing the fusion level to T10-ilium may lower the risk of screw loosening. In terms of screw failure and proximal ASD, however, T10-ilium fusion has a higher potential risk compared with other fusion types. These results will contribute for surgeons to provide adequate patient education regarding screw failure and proximal ASD, when performing multilevel lumbar fusion.ope

Gastrointestinal Risk Assessment in the Patients Taking Nonsteroidal Anti-inflammarory Drugs for Lumbar Spinal Disease

Study Design: A cross-section observational study. Objectives: To evaluate the current prescription patterns of non-steroidal anti-inflammatory drugs (NSAIDs) and gastrointestinal (GI) risk assessment in patients with lumbar spine disease. Summary of Literature Review: NSAIDs are commonly prescribed medications for lumbar spine disease patients. Since the rate of GI complication varies for each patient, identification of individual GI risks is a prerequisite to prevent such a complication. There are few reports about the GI risks in patients with lumbar spine disease who take NSAIDs. Materials and Methods: 2264 patients with lumbar degenerative spondylopathy who were taking NSAIDs were enrolled from May 2010 to September 2010. The Standardized Calculator of Risk for Event (SCORE) was used to measure patients’ GI risk factors. NSAID prescription patterns and GI protective agents were also investigated. Results: Being aged over 65 (1098 patients; 48.5%) and the presence of GI side-effects from NSAIDs (896 patients;,39.6%) were the most common risk factors. 31.9% and 5.8% percent of patients belonged to each of the high risk and the very high risk groups in GI risk factor analysis. The total prescription rate of gastroprotectants was 91.7% for all patients. However, the prescription rate of selective COX-2 inhibitors in the high risk group was low, and in 54.8% of patients who took COX-2 inhibitors there was GI discomfort. Conclusions: The prescription pattern of GI protective agents was not correlated with GI symptoms. Therefore, physicians should consider NSAID prescription based on the GI risk factors of individual patientsope

Biomechanical Comparison of Posterior Fixation Combinations with an Allograft Spacer between the Lateral Mass and Pedicle Screws

Background: There are a few biomechanical studies that describe posterior fixation methods with pedicle screws (PS) and lateral mass screws (LMS); the combination of both screw types and their effect on an allograft spacer in a surgically treated cervical segment is unknown. Methods: Finite element model (FEM) analyses were used to investigate the effects of a hybrid technique using posterior PS and LMS. Stress distribution and subsidence risk from a combination of screws under hybrid motion control conditions, including flexion, extension, axial rotation, and lateral bending, were investigated to evaluate the biomechanical characteristics of different six-screw combinations. Findings: The load sharing on the allograft spacer in flexion mode was highest in the LMS model (74.6%) and lowest in the PS model (35.1%). The likelihood of subsidence of allograft spacer on C6 was highest in the screws from the distal LMS (type 5) model during flexion and extension (4.902 MPa, 30.1% and 2.189 MPa, 13.4%). In lateral bending, the left unilateral LMS (type 4) model screws on C5 (3.726 MPa, 22.9%) and C6 (2.994 MPa, 18.4%) yielded the greatest subsidence risks, because the lateral bending forces were supported by the LMS. In counterclockwise axial rotation, the left unilateral LMS (type 4) model screws on C5 (3.092 MPa, 19.0%) and C6 (3.076 MPa, 18.9%) demonstrated the highest subsidence risks. Conclusion: The asymmetrical ipsilateral use of LMS and posterior PS in lateral bending and axial rotation demonstrated the lowest stability and greatest subsidence risk. We recommend bilateral symmetrical insertion of LMS or posterior PS and posterior PS on distal vertebrae for increased stability and reduced risk of allograft spacer subsidenceope

Efficacy of computed tomography in prediction of operability of L5/S1 foraminal stenosis using region of interest: A STROBE-compliant retrospective study

Symptoms of intervertebral foraminal stenosis are caused by compression of nerve root exiting the intervertebral foramen. Many attempts to measure the size of the neuromuscular exit have been made; however, only a few studies to compare the area differences between foramens by computed tomography (CT) were done. In this retrospective comparative study, we used the region of interest (ROI) in CT to measure and compare the area of intervertebral foramen between the healthy control group and the patient group.Eighty-one patients who underwent CT of the lumbar spine between May 2014 and December 2017 were enrolled. Using the medical imaging program, the foraminal area between L5 and S1 vertebrae was measured on the sagittal, coronal, and axial planes using ROI. Four groups were established for comparison: those diagnosed with foraminal stenosis by a radiologist and those who were not, those diagnosed with foraminal stenosis by orthopedic surgeons and those who were not. These groups were further divided into subcategories depending on whether the area was operated on for foraminal stenosis. Interobserver and intraobserver agreements were assessed.The mean age of patients was 56.5 years (range 17-84). The foraminal area of the surgical group on sagittal plane was significantly narrower than the control group (P = .005). However, the difference between the 2 groups on axial and coronal planes was not statistically significant (P > .1). Foraminal area 0.9).In this study, we proved that measuring the intervertebral foraminal area using the ROI in CT in the lumbar spine is useful for diagnosing L5-S1 foraminal stenosis, especially on sagittal plane. Furthermore, not only does it provide aid in diagnosis, but it also helps predicting the operability of foraminal stenosis.ope

Clinical Outcome of the Operative Treatment for Lumbar Degenerative Spondylopathy in Patients Undergoing Dialysis

STUDY DESIGN: This is a retrospective review. OBJECTIVES: We wanted to evaluate the clinical and radiological outcomes of operative treatment for lumbar degenerative diseases in patients who are undergoing dialysis. SUMMARY OF THE LITERATURE REVIEW: Operative treatment for patients having spinal diseases with chronic renal failure (CRF) demands special consideration because of the medical and surgical complications and the poor clinical outcome. There are only few reports on operative treatment for lumbar degenerative diseases for patients who are undergoing dialysis. MATERIALS AND METHODS: Eight patients with lumbar degenerative spondylopathy and CRF and who were undergoing dialysis were operated on from August 1998 to September 2007. The clinical and radiological outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scale and the plain X-rays. The serum alkaline phosphatase levels were measured to evaluate the bone metabolism along with the postoperative improvement of clinical symptom. RESULTS: We had 1 case of postoperative mortality with peritoneal dialysis due to sepsis that was caused by panperitonitis and another complication of discitis. Only 1 of 4 cases that underwent fusion procedure had radiological bony union. The mean JOA scores were 12.0 (range: 10-14) preoperatively and 17.3 (range: 5-20) and 15.6 (range: 9-19) at postoperative 6 months and the final follow-up, respectively (p0.05). CONCLUSIONS: The clinical outcomes of surgical treatments were improved for the degenerative spine disease patients who are undergoing dialysis. However after the fusion procedure, the bony fusion rate was low (25%). Since a high rate of perioperative medical complications can be expected, thorough medical evaluation during preoperation and postoperation is recommendedope

Medial Pedicle Pivot Point Using Preoperative Computed Tomography Morphometric Measurements for Cervical Pedicle Screw Insertion: A Novel Technique and Case Series

This study describes a new and safe freehand cervical pedicle screw insertion technique using preoperative computed tomography (CT) morphometric measurements as a guide and a medial pedicle pivot point (MPPP) during the procedure. This study included 271 pedicles at 216 cervical spine levels (mean: 4.75 pedicles per patient). A pedicle diameter (PD) ≥ 3.5 mm was the cut-off for pedicle screw fixation. The presence and grade of perforation were detected using postoperative CT scans, where perforations were graded as follows: 0, no perforation; 1, perforation 1.75 mm. The surgical technique involved the use of an MPPP, which was the point at which the lines representing the depth of the lateral mass and total length of the pedicle intersected, deep in the lateral mass. The overall success rate was 96.3% (261/271, Grade 0 or 1 perforations). In total, 54 perforations occurred, among which 44 (81.5%) were Grade 1 and 10 (18.5%) were Grade 2. The most common perforation direction was medial (39/54, 72.2%). The freehand technique for cervical pedicle screw fixation using the MPPP may allow for a safe and accurate procedure in patients with a PD ≥3.5 mm.ope

Emphysematous osteomyelitis of the spine: A rare case report

Rationale: Emphysematous osteomyelitis is a rare disease caused by gas-forming bacteria. But only 45 cases have been reported in the literature since then. Patient concerns: A 72-year-old female presented to our hospital with severe lower back pain that aggravated 4 days ago. Diagnoses: Computed tomography (CT) revealed intraosseous mottled air in the T12 and L1 vertebral bodies and epidural space. The enhanced T1 and T2 magnetic resonance imaging scans showed heterogeneous signal intensity of vertebral bodies, suggestive of emphysematous osteomyelitis. Interventions: Surgery was performed to identify culture strains and to remove emphysematous lesions of the vertebral body using extensive transpedicular irrigation. Outcomes: Escherichia coli (E coli) was identified in the surgical specimen, and intravenous antibiotic therapy was continued with cefotaxime. The patient had a significant decrease in lower back pain after the surgery and the final CT scan before discharge revealed significantly decreased air at T12 and L1 vertebral bodies and no air density in the epidural space. Lessons: We present a patient diagnosed with emphysematous osteomyelitis in vertebral bodies caused by E coli and successfully treated with surgical intervention.ope

Delirium after Spinal Surgery: A Pilot Study of Electroencephalography Signals from a Wearable Device

Postoperative delirium after spinal surgery in elderly patients has been a recent concern. However, there has not been a study of delirium after spinal surgery based on electroencephalography (EEG) signals from a compact wearable device. We aimed to analyze differences in EEG signals from a wearable device in patients with and without delirium after spinal surgery. Thirty-seven patients who underwent cervical or lumbar decompression and instrumented fusion for degenerative spinal disease were included. EEG waves were collected from a compact wearable device, and percentage changes from baseline to within 1 week and 3 months after surgery were compared between patients with and without delirium. In patients with delirium, the anxiety- and stress-related EEG waves—including the H-beta (19.3%; p = 0.003) and gamma (18.8%; p = 0.006) waves—and the tension index (7.8%; p = 0.011) increased, and the relaxation-related theta waves (−23.2%; p = 0.016) decreased within 1 week after surgery compared to the non-delirium group. These results will contribute to understanding of the EEG patterns of postoperative delirium and can be applied for the early detection and prompt treatment of postoperative delirium after spinal surgery.ope

Biomechanical Comparison and Three-Dimensional Analysis of Cement Distribution Patterns for Different Pedicle Screw Designs

The purpose of this study to explore strategies for reducing cement leakage during cement-augmented pedicle screw fixation, we compared the cement distribution patterns and biomechanical strengths of different types of cement-augmented fenestrated screws and traditional cement-augmented techniques. We compared five screw groups in this study: (1) Cannulated screws (Cann); (2) distal one-hole screws (D1); (3) distal two-hole screws (D2); (4) middle two-hole screws (M2); and (5) traditional screws with a traditional cement injection technique (Trad). The screws were inserted into cancellous bone blocks using a controlled, adequate cement injection pressure (1.6-2.0 kg), and an appropriate cement viscosity. Center to screw tip distance, three-dimensional distribution, and pull-out strength for cement were compared between groups. The average distance between the cement center and the screw tip was highest in the M2 group, suggesting a higher risk of cement leakage into the spinal canal. The Trad group had the highest migration distance in the z-axis, also reflecting a higher risk of leakage into the spinal canal. The D1 group had the highest pull-out strength (253 ± 48.82 N and 797 ± 58.31 N) in bone blocks representing different degrees of osteoporosis, and the D2 group had the second highest pull-out strength in the severe osteoporosis model. Overall, D1 screws appeared to be the best option for optimizing biomechanical function and minimizing the risk of cement leakage into the spinal canal in patients with osteoporotic bone undergoing spinal surgery.ope