Myelography in the Assessment of Degenerative Lumbar Scoliosis and Its Influence on Surgical Management

Lumbar Spine Anatomy in Supine versus Weight- Bearing Magnetic Resonance Imaging: Detecting Significant Positional Changes and Testing Reliability of Quantification

STUDY DESIGN

Testing between and within group differences and assessing reliability of measurements.

PURPOSE

To study and compare lumbar spine morphology in supine and weight-bearing (WB) magnetic resonance imaging (MRI).

OVERVIEW OF LITERATURE

Upright lumbar MRI may uncover anatomical changes that may escape detection when using conventional supine imaging. This study quantified anatomical dimensions of the lumbar spine in the supine and WB MRI, compared specific morphometric differences between them, and tested the intra-rater reliability of the measurements. Repeated measures analysis was used to compare within- and between-session measurements performed on the supine and WB images. Reliability and agreement were assessed by calculating intraclass correlation (ICC) coefficient.

METHODS

Data from 12 adults without any history of back pain were used in this study. Sagittal T2-weighted images of the lumbar spine were acquired in the supine and WB positions twice (in two separate sessions scheduled within a week). Linear, angular dimensions, and cross-sectional areas (CSAs) were measured using proprietary software. Supine and WB data acquired from the two imaging sessions were tested for intra-rater reliability. Quantified data were normalized for each session to test the significance of differences. ICC was calculated to test the reliability of the measurements.

RESULTS

Linear, angular, and CSA measurements demonstrated strong within-position (supine and WB) correlations (r -values, 0.75-0.97). Between-position (supine vs. WB) differences were significant for all measured dimensions (p<0.05). Between-session measurements demonstrated a strong correlation (r -values, 0.64-0.83). Calculated ICC showed strong agreement among the measurements.

CONCLUSIONS

Anatomical dimensions of the lumbar spine may demonstrate consistent and significant differences between supine and WB MRI for specific structural parameters.

Evaluation of Safety and Efficacy of Preoperative Coronal MRI-Guided Minimally Invasive Surgery for Cervical Spondylotic Radiculopathy

BACKGROUND Key-hole surgery is a minimally invasive technique that has shown promise in various surgical procedures. This study aimed to assess the clinical effectiveness of preoperative coronal MRI-assisted key-hole surgery for the treatment of patients with cervical spondylotic radiculopathy (CSR). MATERIAL AND METHODS A total of 30 patients diagnosed with CSR and undergoing key-hole surgery with CMRI assistance were included in the study. Various parameters, including surgical segments, incision length, disease duration, operative time, intraoperative fluoroscopy times, intraoperative blood loss, complications, and length of hospitalization, were recorded. Precise measurements of Cobb angles and intervertebral space height were taken before and after the surgical procedure. Surgical outcomes were evaluated using modified Macnab criteria, visual analogue scale (VAS), Japanese Orthopaedic Association Scores (JOA), and neck disability index (NDI). RESULTS The average duration of disease was 6.47±3.29 months, with an average incision length of 1.94±0.15 cm and operative time of 57.83±4.34 minutes. The average intraoperative blood loss was 33.70±9.28 ml, with an average of 3.50±0.73 intraoperative fluoroscopies. The average duration of hospitalization was 4.10±1.27 days. Preoperative and postoperative measurements showed no statistically significant difference in C2-C7 Cobb angles and intervertebral space height. However, there were significant improvements in postoperative VAS, NDI, and JOA scores compared to preoperative scores. The surgical effectiveness rate was 100%, with a high rate of good and excellent outcomes. CONCLUSIONS The findings of this study suggest that preoperative CMRI-assisted key-hole surgery for single-segment CSR is a safe and effective treatment option with low complication rates. The clinical benefits include high security and good outcomes. Further research and larger studies are warranted to validate these findings.

When does CT myelography add value beyond MRI for lumbar degenerative disease?

BACKGROUND CONTEXT

In patients with lumbar spinal stenosis, it is crucial for clinicians to identify all symptomatic levels. Prior studies have demonstrated that CT myelography has a greater sensitivity in revealing stenosis (94.4%) compared to MRI (75.9%). However, this is an invasive test that should be used judiciously. No study has identified subgroups of patients that do or do not benefit from this additional invasive testing.

PURPOSE

The objective of this study was to identify subgroups of patients with lumbar stenosis for whom CT myelogram could be expected to provide additional information following an MRI scan.

STUDY DESIGN

Retrospective chart review.

PATIENT SAMPLE

Consecutive series of patients with lumbar degenerative disease seen at a single multisurgeon tertiary spine center.

OUTCOME MEASURES

Degree of stenosis on MRI or CT myelo.

METHODS

Medical records were reviewed to collect standard demographic and surgical data and patient diagnoses. MRI and CT myelo obtained within 6 months of each other in patients >45 years old with a diagnosis of central stenosis, spondylolisthesis or degenerative scoliosis were reviewed. Each lumbar level was recorded as mild, moderate, or severe based on the radiologist's report. Fisher exact test was performed with change in recorded severity of stenosis from MRI to CT myelo as the primary outcome of interest.

RESULTS

Of 269 patients, 207 (80%) had at least one level of moderate or severe central stenosis on MRI and 62 had mild or no stenosis on MRI. Of the 207, 139 (67%) had multilevel stenosis and 68 (33%) had single level stenosis. CT myelo identified a greater proportion of additional stenotic levels in patients with multilevel stenosis (80/139, 58%) compared to patients with single-level stenosis (27/68, 40%, p=.018). In 62 patients with a clinical diagnosis of lumbar stenosis but no moderate to severe stenosis on MRI, CT myelogram identified three additional stenotic levels (3/65, 5%, p=.836).

CONCLUSIONS

CT myelography is not as useful in providing additional information in patients with no stenosis or single level stenosis as compared to patients with multilevel stenosis.

The normal appearance of CT myelograms

PURPOSE

CT myelography has been used since 1976 to diagnose neural compression in the axial skeleton. With the advent of routine MRI, its role in accurately diagnosing neural compression has been questioned as its normal appearances are not defined in the study. In this study, we examine a series of CT myelograms to define the normal appearances of the neural elements of the spine.

METHODS

The CT myelograms of patients with unilateral symptoms were examined by four independent physicians. The lateral extent of contrast was examined and recorded. Concordance between the recorded extents was assessed using kappa scores.

RESULTS

Thirty-six scans were reviewed. Kappa analysis shows that there is a fair agreement in the lateral extent of contrast at L1, L3 and L4. At L2 and L5, agreement is slight.

CONCLUSION

The interpretation of CT myelography shows significant interobserver variability. As a result, the usefulness of this diagnostic tool can be questioned, and if misinterpreted, it could lead to questionable diagnoses and inadvertently erroneous management if used in isolation. These slides can be retrieved under Electronic Supplementary Material.