Clinical Importance of MRI in Thoracolumbar Spinal Fracture / 대한척추외과학회지

STUDY DESIGN: Retrospective radiologic assessment OBJECTIVES: To assess the clinical importance of MRI for the diagnosis of posterior spinal ligament complex injuries in thoracolumbar fractures. SUMMARY OF LITERATURE REVIEW: Evaluation of spinal instability is important in thoracolumbar fractures. When simple radiography and CT alone are performed, spinal instability may be missed, especially that involving the posterior spinal ligament complex. MATERIALS AND METHODS: Eighty-seven patients who were evaluated using simple radiography, computed tomography (CT), and magnetic resonance imaging (MRI) between March 1994 and March 2003 were included in the study. The local kyphotic angle was measured on lateral radiography, and it was then compared to the fracture pattern on MRI. Statistical analysis was performed using ANOVA. RESULTS: There was no correlation between the local kyphotic angle on radiography and fracture involvement on MRI (p=0.106). In 41 patients who were found to have involvement of the anterior column on CT, 25 had anterior column involvement, 4 had middle column involvement, and 12 had posterior column involvement on MRI. In 36 patients who were found to have involvement of the middle column on CT, 17 had involvement of the middle column and 19 had involvement of the posterior column on MRI. The fractures of the ten patients who were found to have posterior column involvement on CT were all seen on MRI. The coincidence of fracture patterns between CT and MRI, which was evaluated using Cohen's Kappa analysis, was 0.434. The sensitivity of CT compared with MRI was 0.741 in the middle column and 0.243 in the posterior column. CONCLUSIONS: Many thoracolumbar fractures are missed on both simple radiography and CT. MRI is essential for accurate diagnosis of posterior spinal ligament complex injuries, especially when there is involvement above the middle column, or when canal encroachment is seen on CT.

MRI Assessments of Adjacent Disc Degeneration Following Lumbar Fusion / 대한척추외과학회지

STUDY DESIGN: Retrospective case-control study OBJECTIVE: To use MRI to assess intervertebral disc degeneration at adjacent levels after spinal fusion and after discectomy. SUMMARY OF LITERATURE REVIEW: Degeneration of adjacent intervertebral discs following lumbar spinal fusion is one of the principal reasons for considering motion preservation techniques, such as placement of an artificial disc. Much attention has recently been directed toward disc morphometric studies using MRI. MATERIALS AND METHODS: Fifty-six patients who underwent spinal surgery for lumbar degenerative disease and who underwent a minimum of 2 years of follow-up MRIs were included in this study. Thirty-four patients were included in the lumbar fusion study group, and 22 patients were included in the discectomy control group. The MRI Thompson classification was used to grade both upper and lower adjacent disc degeneration preoperatively and at the time of last follow-up. RESULTS: There were significant changes in Thompson degenerative grade in the upper adjacent levels for both the fusion group patients and in the discectomy group patients. However, there was no statistically significant difference between the two groups with regard to either the upper or lower adjacent levels (p=0.146 and 0.350, respectively). CONCLUSIONS: In this short-term study comparing MRI outcomes in spinal fusion and discectomy patients, no significant difference in adjacent disc degeneration was observed between the two group.

The Changes in the Dimensions of Neural Foramen After Anterior Interbody Fusion in the Spondylolisthesis / 대한척추외과학회지

STUDY DESIGN: A prospective radiological assessment was performed using computerized tomography measurements. OBJECTIVES: The aim of this study was to assess the changes in the dimensions of the neural foramen after anterior interbody fusion with posterior fixation in spondylolisthesis. SUMMARY OF LITERATURE REVIEW: Anterior lumbar interbody fusion distracts the height and width of the neural foramen. MATERIALS AND METHODS: Anterior interboody fusion with posterior fixation was performed in twenty-five patients. The sagittal parameters were the height and area of the neural foramen. The fused lumbar segments was imaged in the direct sagittal projections in a CT (SOMATOM Senstaion; SIMENS, Germany) and 1-mm slice thickness before surgery and after solid fusion. Computer digitation was used for the measurements independently by three different observers. Statistical analysis was performed using a Wilcoxon signed test and a paired T-test to determine the correlation between the measurements, and Pearson correlation to determine the level of interobserver and intraobserver agreement. RESULTS: After anterior interbody fusion and posterior fixation, the height and the area of the neural foramen had increased significantly by 15.5+/-14.0%(p.0.001) and 23.2+/-17.7%(p.0.001). There was a significant confidence in interobserver (0.9466~0.9996) and intraobserver(0.8896~0.9991) agreement. CONCLUSIONS: Anterior interbody fusion significantly increased the changes in the dimensions of the neural foramen. Anterior distraction and decompression with anterior interbody fusion increased the area of the neural foramen This study shows that anterior interbody fusion can be used to decompress the neural foramen in the spondylolisthesis.