Seung Hwan Yoon

Complete Spinal Cord Injury Treatment Using Autologous Bone Marrow Cell Transplantation and Bone Marrow Stimulation with Granulocyte Macrophage‐Colony Stimulating Factor: Phase I/II Clinical Trial

To assess the safety and therapeutic efficacy of autologous human bone marrow cell (BMC) transplantation and the administration of granulocyte macrophage‐colony stimulating factor (GM‐CSF), a phase I/II open‐label and nonrandomized study was conducted on 35 complete spinal cord injury patients. The BMCs were transplanted by injection into the surrounding area of the spinal cord injury site within 14 injury days (n = 17), between 14 days and 8 weeks (n = 6), and at more than 8 weeks (n = 12) after injury. In the control group, all patients (n = 13) were treated only with conventional decompression and fusion surgery without BMC transplantation. The patients underwent preoperative and follow‐up neurological assessment using the American Spinal Injury Association Impairment Scale (AIS), electrophysiological monitoring, and magnetic resonance imaging (MRI). The mean follow‐up period was 10.4 months after injury. At 4 months, the MRI analysis showed the enlargement of spinal cords and the small enhancement of the cell implantation sites, which were not any adverse lesions such as malignant transformation, hemorrhage, new cysts, or infections. Furthermore, the BMC transplantation and GM‐CSF administration were not associated with any serious adverse clinical events increasing morbidities. The AIS grade increased in 30.4% of the acute and subacute treated patients (AIS A to B or C), whereas no significant improvement was observed in the chronic treatment group. Increasing neuropathic pain during the treatment and tumor formation at the site of transplantation are still remaining to be investigated. Long‐term and large scale multicenter clinical study is required to determine its precise therapeutic effect.

GM-CSF inhibits apoptosis of neural cells via regulating the expression of apoptosis-related proteins

Recently, we reported that GM-CSF showed therapeutic effects on the spinal cord injury (SCI) in rat model possibly via its anti-apoptotic activity in the nervous system. This study investigated the molecular mechanism of its anti-apoptotic and neuroprotective effects in N2a neuroblastoma cells and in rat SCI model. GM-CSF inhibited staurosporine-induced cytotoxicity and apoptosis of N2a cells. Single administration of GM-CSF either intraperitoneally or locally using a gelfoam, clearly reduced the apoptotic events in the surrounding region of the injury site in rat SCI model. Immunohistochemical analysis showed that apoptosis of cells occurred mainly in the neurons, but not significantly in the astrocytes in the surrounding regions. In both N2a cells and in rat SCI model, GM-CSF actually reduced the expression of pro-apoptotic proteins (p53, p21(WAF1/CIP1) and Bax), while further induced that of an anti-apoptotic protein (Bcl-2). In the Basso-Beattie-Bresnahan (BBB) locomotor test, the single GM-CSF administration showed better behavioral recovery than the untreated control only at early times within 1 week after injury. Overall, GM-CSF was shown to exert its neuroprotective effect on the neural injury by regulating the expression of apoptosis related genes, providing the molecular basis on its anti-apoptotic activity. Longer administration of GM-CSF appeared to be necessary for the sustained functional recovery from SCI.

GM-CSF inhibits glial scar formation and shows long-term protective effect after spinal cord injury

OBJECT This study investigated the effects of granulocyte macrophage-colony stimulating factor (GM-CSF) on the scar formation and repair of spinal cord tissues in rat spinal cord injury (SCI) model. METHODS Sprague-Dawley male rats (8 weeks old) were randomly divided into the sham-operated group, spinal cord injury group, and injury with GM-CSF treated group. A spinal cord injury was induced at T9/10 levels of rat spinal cord using a vascular clip. GM-CSF was administrated via intraperitoneal (IP) injection or on the dural surface using Gelfoam at the time of SCI. The morphological changes, tissue integrity, and scar formation were evaluated until 4 weeks after SCI using histological and immunohistochemical analyses. RESULTS The administration of GM-CSF either via IP injection or local treatment significantly reduced the cavity size and glial scar formation at 3-4 weeks after SCI. GM-CSF also reduced the expression of core proteins of chondroitin sulfate proteoglycans (CSPGs) such as neurocan and NG2 but not phosphacan. In particular, an intensive expression of glial fibriallary acidic protein (GFAP) and neurocan found around the cavity at 4 weeks was obviously suppressed by GM-CSF. Immunostaining for neurofilament (NF) and Luxol fast blue (LFB) showed that GM-CSF preserved well the axonal arrangement and myelin structure after SCI. The expression of GAP-43, a marker of regenerating axons, also apparently increased in the rostral grey matter by GM-CSF. CONCLUSION These results suggest that GM-CSF could enhance long-term recovery from SCI by suppressing the glial scar formation and enhancing the integrity of axonal structure.

Free Hand Pedicle Screw Placement in the Thoracic Spine without Any Radiographic Guidance : Technical Note, a Cadaveric Study

Thoracic pedicle screw fixation techniques are still controversial for thoracic deformities because of possible complications including neurologic deficit. Methods to aid the surgeon in appropriate screw placement have included the use of intraoperative fluoroscopy and/or radiography as well as image-guided techniques. We describe our technique for free hand pedicle screw placement in the thoracic spine without any radiographic guidance and present the results of pedicle screw placement analyzed by computed tomographic scan in two human cadavers. This free hand technique of thoracic pedicle screw placement performed in a step-wise, consistent, and compulsive manner is an accurate, reliable, and safe method of insertion to treat a variety of spinal disorders, including spinal deformity.

Signal transduction pathways of GM-CSF in neural cell lines.

GM-CSF is recently being suggested to play important role(s) in the nervous system. Present study was intended to understand signal transduction pathways of GM-CSF in human neuroblastoma (SK-N-(BE)2) and glioblastoma (A172) cell lines. The expression of GM-CSF receptors on the surface of these cells was confirmed by immunocytochemistry, Western blot analysis and RT-PCR. When treated for 10min, GM-CSF activated the signal transducer and activator of transcription 5 (STAT5) and extracellular signal regulated kinase (ERK) in both cell lines. However, Janus kinase 2 (JAK2) was activated only in A172 cells but not in SK-N-(BE)2 cells by GM-CSF. The GM-CSF-activated cellular signal pathways were specifically inhibited by the pretreatment of GM-CSF receptor alpha antibody, suggesting the specificity of the signal activation. The experiment using specific inhibitors (AG490) to the JAK/STAT pathway showed that JAK2/STAT5 cascade was well preserved and activated by GM-CSF in A172 cells, while STAT5 was activated by GM-CSF without JAK2 activation in SK-N-(EB)2 cells. The ERK pathway was activated by GM-CSF independently of JAK2 in both cell lines. Finally, GM-CSF showed cytoprotective effect on these cell lines by inhibiting cytotoxicity of saturosporine. The results revealed the signal transduction pathways activated by GM-CSF in neural cells and suggested that GM-CSF might affect the neural functions via these signal pathways.

Comparative Study of Outcomes between Shunting after Cranioplasty and in Cranioplasty after Shunting in Large Concave Flaccid Cranial Defect with Hydrocephalus

OBJECTIVE The cranioplasty and ventriculoperitoneal (VP) shunt operation have been used to treat a large cranial defect with posttraumatic hydrocephalus (PTH). The aim of this study was to evlauate the difference of outcomes between in the shunting after the cranioplasty (group 1) and the cranioplasty after the shunting (group 2) in a large flaccid cranial defect with PTH. METHODS In this study, a retrospective review was done on 23 patients undergoing the cranioplasty and VP shunt operation after the decompressive craniectomy for a refractory intracranial hypertension from 2002 to 2005. All of 23 cases had a large flaccid concave cranial defect and PTH. Ten cases belong to group 1 and 13 cases to group 2. The outcomes after operations were compared in two groups 6 months later. RESULTS The improvement of Glasgow outcome scale (GOS) was seen in 8 cases (80.0%) of total 10 cases in group 1, and 6 cases (46.2%) of 13 cases in group 2. Three (75.0%) of 4 cases with hemiparesis in group 1 and 3 of 6 cases (50.0%) in group 2 were improved. All cases (2 cases) with decrease of visual acuity were improved in each group. Dysphasia was improved in 3 of 5 cases (60%) in group 1 and 4 of 6 cases (66.6%) in group 2. CONCLUSION These results suggest that outcomes in group 1 may be better than in group 2 for a large flaccid concave cranial defect with PTH.

Time Course of Symptom Disappearance after Microvascular Decompression for Hemifacial Spasm

OBJECTIVE This study is to investigate time course of symptom disappearance in patients whose spasm relieved completely after microvascular decompression (MVD). METHODS Of 115 patients with hemifacial spasm (HFS) who underwent MVD from April 2003 to December 2006, 89 patients who had no facial paralysis after operation and showed no spasm at last follow-up more than 1.5 years after operation were selected. Symptom disappearance with time after MVD was classified into type 1 (symptom disappearance right after operation), type 2 (delayed symptom disappearance) and type 3 (unusual symptom disappearance). Type 2 was classified into type 2a (with postoperative silent period) and type 2b (without silent period). RESULTS Type 1, type 2a, type 2b and type 3 were 38.2%, 48.37%, 12.4% and 1.1%, respectively. Delayed disappearance group (type 2) was 60.7%. Post-operative symptom duration in all cases ranged from 0 to 900 days, average was 74.6 days and median was 14 days. In case of type 2, average post-operative symptom duration was 115.1 days and median was 42 days. Five and 3 patients required more than 1 year and 2 years, respectively, until complete disappearance of spasm. In type 2a, postoperative silent period ranged from 1 to 10 days, with an average of 2.4 days. CONCLUSION Surgeons should be aware that delayed symptom disappearance after MVD for HFS is more common than it has been reported, silent period can be as long as 10 days and time course of symptom disappearance is various as well as unpredictable.

Spinal cord injury without radiological abnormality in an infant with delayed presentation of symptoms after a minor injury.

Study Design. We present a very rare case of an infant with delayed presentation of spinal cord injury without radiologic abnormality (SCIWORA) after a minor injury. Objective. To emphasize the importance of spinal evaluation with MRI in selected cases, even after minor injuries, especially in infants. Summary of Background Data. SCIWORA arises mainly in infants and children during accidental trauma or after sport injury. However, it has been very rare for a 6-day-delayed infant SCIWORA after a minor injury. Methods. An infant presented with transient nausea and vomiting after falling from a baby-rocking horse of less than 30-cm height. The patient demonstrated right hemiparesis 6 days later. Plain cervical radiographs and brain and cervical spine computed tomograms (CT) were normal, but the cervical magnetic resonance imaging (MRI) demonstrated a high signal in the T2-weighted image of the lower cervical cord, and a neck collar was applied. Results. A follow-up cervical MRI 1 month later showed that the high signal of the lower cervical cord had disappeared. Another follow-up cervical MRI 12 months later also showed normal radiographic findings but there still remained mild weakness of the right lower extremities. Conclusion. The authors present a rare case of infant SCIWORA who developed delayed neurologic symptoms 6 days after a minor injury and suggest that spinal evaluation with MRI could be warranted in the selected case even after minor injuries, especially in infants.

A Multi-center Clinical Study of Posterior Lumbar Interbody Fusion with the Expandable Stand-alone Cage (Tyche® Cage) for Degenerative Lumbar Spinal Disorders

OBJECTIVE This multi-center clinical study was designed to determine the long-term results of patients who received a one-level posterior lumbar interbody fusion with expandable cage (Tyche(R) cage) for degenerative spinal diseases during the same period in each hospital. METHODS Fifty-seven patients with low back pain who had a one-level posterior lumbar interbody fusion using a newly designed expandable cage were enrolled in this study at five centers from June 2003 to December 2004 and followed up for 24 months. Pain improvement was checked with a Visual Analogue Scale (VAS) and their disability was evaluated with the Oswestry Disability Index. Radiographs were obtained before and after surgery. At the final follow-up, dynamic stability, quality of bone fusion, interveretebral disc height, and lumbar lordosis were assessed. In some cases, a lumbar computed tomography scan was also obtained. RESULTS The mean VAS score of back pain was improved from 6.44 points preoperatively to 0.44 at the final visit and the score of sciatica was reduced from 4.84 to 0.26. Also, the Oswestry Disability Index was improved from 32.62 points preoperatively to 18.25 at the final visit. The fusion rate was 92.5%. Intervertebral disc height, recorded as 9.94+/-2.69 mm before surgery was increased to 12.23+/-3.31 mm at postoperative 1 month and was stabilized at 11.43+/-2.23 mm on final visit. The segmental angle of lordosis was changed significantly from 3.54+/-3.70 degrees before surgery to 6.37+/-3.97 degrees by 24 months postoperative, and total lumbar lordosis was 20.37+/-11.30 degrees preoperatively and 24.71+/-11.70 degrees at 24 months postoperative. CONCLUSION There have been no special complications regarding the expandable cage during the follow-up period and the results of this study demonstrates a high fusion rate and clinical success.

Evaluation of Spinal Fusion Using Bone Marrow Derived Mesenchymal Stem Cells with or without Fibroblast Growth Factor-4.

OBJECTIVE In this study, the authors assessed the ability of rat bone marrow derived mesenchymal stem cells (BMDMSCs), in the presence of a growth factor, fibroblast growth factor-4 (FGF-4) and hydroxyapatite, to act as a scaffold for posterolateral spinal fusion in a rat model. METHODS Using a rat posterolateral spine fusion model, the experimental study comprised 3 groups. Group 1 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite only. Group 2 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite containing 1 x 10(6)/ 60 microL rat of BMDMSCs. Group 3 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite containing 1 x 10(6)/ 60 microL of rat BMDMSCs and FGF-4 1 microG to induce the bony differentiation of the BMDMSCs. Rats were assessed using radiographs obtained at 4, 6, and 8 weeks postoperatively. After sacrifice, spines were explanted and assessed by manual palpation, high-resolution microcomputerized tomography, and histological analysis. RESULTS Radiographic, high-resolution microcomputerized tomographic, and manual palpation revealed spinal fusion in five rats (83%) in Group 2 at 8 weeks. However, in Group 1, three (60%) rats developed fusion at L4-L5 by radiography and two (40%) by manual palpation in radiographic examination. In addition, in Group 3, bone fusion was observed in only 50% of rats by manual palpation and radiographic examination at this time. CONCLUSION The present study demonstrates that 0.08 gram of hydroxyapatite with 1 x 10(6)/ 60 microL rat of BMDMSCs induced bone fusion. FGF-4, added to differentiate primitive 1 x 10(6)/ 60 microL rat of BMDMSCs did not induce fusion. Based on histologic data, FGF-4 appears to induce fibrotic change rather than differentiation to bone by 1 x 10(6)/ 60 microL rat of BMDMSCs.