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[False negative myelography in surgically confirmed lumbar intervertebral disk prolapse]
Abstract:
A consecutive series of 821 lumbar myelograms in patients operated on for prolapsed disks were analysed. 47 or 5-7% had to be listed false-negative in spite of excellent technical quality. To find out, whether anatomical variations or a special functional state of the subarachnoid space could have prevented a correct diagnosis, clinical symptoms and some special radiological parameters were examined and statistically evaluated: 1. Distances between peduncles of L4, L5, S1 2. Width of subarachnoid space in a coronal section of L4, L5, S1 3. Width of subarachnoid space in a sagittal section of L5 4. Distance between the posterior limit of the body of L5 and the anterior limit of the subarachnoid space. Measurement and statistical correlations did not reveal any correlation between false-negative myelograms and any of the anatomical variants measured. We still cannot rule out false-negative myelograms.
Insights
Lumbar myelograms for prolapsed disks can be false-negative, even with good technique. Anatomical variations in the subarachnoid space did not explain these diagnostic errors in this study.
Area of Science:
- Radiology
- Neurosurgery
- Orthopedics
Background:
- Lumbar myelography is a diagnostic tool for prolapsed intervertebral disks.
- A significant percentage of myelograms may yield false-negative results despite technical quality.
Purpose of the Study:
- To investigate if anatomical variations or functional states of the subarachnoid space contribute to false-negative lumbar myelograms in patients with prolapsed disks.
Main Methods:
- Analysis of 821 consecutive lumbar myelograms in surgically treated prolapsed disk patients.
- Evaluation of clinical symptoms and radiological parameters including pedicle distances and subarachnoid space widths at L4, L5, and S1.
- Statistical correlation of measurements with false-negative myelogram findings.
Main Results:
- 5.7% of myelograms were false-negative despite excellent technical quality.
- No statistically significant correlation was found between measured anatomical variants (pedicle distances, subarachnoid space widths) and false-negative myelograms.
- Specific functional states of the subarachnoid space could not be definitively ruled out as a cause.
Conclusions:
- Anatomical variations of the lumbar subarachnoid space do not appear to be the cause of false-negative myelograms in prolapsed disk patients.
- The possibility of false-negative results due to unmeasured factors or functional states remains.
- Further research is needed to fully understand the reasons for false-negative lumbar myelograms.