Sun Kil Choi

Clinical outcome of posterior fixation of the C1 lateral mass and C2 pedicle by polyaxial screw and rod

OBJECTIVE Because of atlantoaxial complex has a unique and complicated anatomy and instability of this complex is very dangerous. We investigated the clinical results of posterior C1-C2 fixation with a polyaxial screw-rod system. METHODS Between July 2001 and December 2007, the authors treated 17 patients suffering from atlantoaxial deformity and instability. Atlantoaxial fusion was employed in 9 patients with upper cervical fracture and dislocation, in 6 patients with atlantoaxial subluxation, in 1 patient with pure transverse ligament injury, and in 1 patient with basilar invagination. The mean age at the time of surgery was 40.4 years (range, 15-68 years). RESULTS Operative times ranged from 165 to 420 min (average 306 min), and the postoperative mean VAS score was 2.4. The mean follow-up period was 26 months. Solid fusion was achieved in 15 patients at the last follow up; no injury of the vertebral artery or spinal cord and no operative mortality occurred in these cases. CONCLUSIONS We suggest that posterior atlantoaxial fixation using the polyaxial screw-rod system is an effective and relatively safe technique. The navigation guidance system employed during the surgical procedure was helpful methods. Future studies of the feasibility of navigation system-guided surgical procedures will be required.

c-Myb Immunoreactivity, Protein and mRNA Levels Significantly Increase in the Aged Hippocampus Proper in Gerbils

Myb genes are a family of transcription factors and have been implicated in the control of the proliferation and differentiation of normal and transformed cells. c-Myb is the best characterized member of the myb family. In the present study, we investigated age-dependent changes of c-myb immunoreactivity, its protein and mRNA level in the hippocampus proper (CA1–3 regions) at various age stages in gerbils. In the postnatal month 1 (PM 1) group, c-myb immunoreactivity was detected in non-pyramidal neurons of the strata oriens and radiatum as well as in pyramidal neurons of the stratum pyramidale. At PM 3, c-myb immunoreactivity and its protein level were similar to those at PM 1. Thereafter, c-myb immunoreactivity and its protein level were increased with time. In the PM 24 group, c-myb immunoreactivity, its protein and mRNA levels were highest. These results suggest that the significant increase of c-myb immunoreactivity, protein and mRNA levels in the aged hippocampus may be associated with neuronal aging.

The pattern of E2F1 and c-myb immunoreactivities in the CA1 region is different from those in the CA2/3 region of the gerbil hippocampus induced by transient ischemia

In this study, we examined transient ischemia-induced changes in transcription factor E2F1 and c-myb expressions in the gerbil hippocampus after 5 min of transient forebrain ischemia. E2F1 immunoreactivity significantly increased in the CA1 region 6-12 h after ischemia/reperfusion. c-myb immunoreactivity increased mainly in CA1 pyramidal cells with time by 12 h after ischemia. Thereafter, E2F1 and c-myb immunoreactivities significantly decreased compared to those in the 12 h post-ischemic group. Four days after ischemia/reperfusion, E2F1 and c-myb immunoreactivities were detected in non-pyramidal cells. Ten days after ischemia, c-myb immunoreactivity increased again: at this time, astrocytes as well as non-pyramidal cells showed E2F1 and c-myb immunoreactivities. In the CA2/3 region, E2F1 and c-myb immunoreactivities mainly changed in non-pyramidal cells, and 10 days after ischemia, c-myb immunoreactivity was not expressed in astrocytes. In conclusion, E2F1 and c-myb significantly alter in pyramidal cells and express in astrocytes in the gerbil hippocampal CA1 region after transient ischemia. These results indicate that E2F1 and c-myb in the CA1 region after ischemic damage may be associated with delayed neuronal death.

The Change of Adjacent Segment and Sagittal Balance after Thoracolumbar Spine Surgery

OBJECTIVE To characterize perioperative biomechanical changes after thoracic spine surgery. METHODS Fifty-eight patients underwent spinal instrumented fusions and simple laminectomies on the thoracolumbar spine from April 2003 to October 2008. Patients were allocated to three groups; namely, the laminectomy without fusion group (group I, n = 17), the thoracolumbar fusion group (group II, n = 27), and the thoracic spine fusion group (group III, n = 14). Sagittal (ADS) and coronal (ADC) angles for adjacent segments were measured from two disc spaces above lesions at the upper margins, to two disc spaces below lesions at the lower margins. Sagittal (TLS) and coronal (TLC) angles of the thoracolumbar junction were measured from the lower margin of the 11th thoracic vertebra body to the upper margin of the 2nd lumbar vertebra body on plane radiographs. Adjacent segment disc heights and disc signal changes were determined using simple spinal examinations and by magnetic resonance imaging. Clinical outcome indices were determined using a visual analog scale. RESULTS The three groups demonstrated statistically significant differences in terms of angle changes by ANOVA (p < 0.05). All angles in group I showed significantly smaller angles changes than in groups II and III by Turkeys multiple comparison analysis. Coronal Cobbs angles of the thoracolumbar spine (TLC) were not significantly different in the three groups. CONCLUSION Postoperative sagittal balance is expected to change in the adjacent and thoracolumbar areas after thoracic spine fusion. However, its prevalence seems to be higher when the thoracolumbar spine is included in instrumented fusion.