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Repeated 3.0 Tesla Magnetic Resonance Imaging After Clinically Successful Lumbar Disc Surgery
Clemens Weber1, Kjell Arne Kvistad, Viggo A Moholdt
1*Department of Neurosurgery, Stavanger University Hospital, Stavanger, Norway†National Advisory Unit on Spinal Surgery, St. Olavs University Hospital, Trondheim, Norway‡Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway§Department of Radiology, St. Olavs University Hospital, Trondheim, Norway¶Department of Neurosurgery, St. Olavs University Hospital, Trondheim, Norway||Norwegian Advisory Unit for Ultrasound and Image-Guided Surgery, St. Olavs University Hospital, Trondheim, Norway.
Study Design:
Prospective cohort study.
Objective:
To describe the naturally occurring magnetic resonance imaging (MRI) findings after successful microsurgical removal of lumbar disc herniation with repeated MRI examinations.
Summary Of Background Data:
The interpretation of MRI after spinal surgery may be particularly challenging and image findings do not always correlate to clinical findings. Early postoperative MRI has limited value in the evaluation of patients after surgery for lumbar disc herniation.
Methods:
Prospective study of 30 successfully operated patients, which underwent 3.0 T MRI within 24 h after surgery for lumbar disc herniation and repeated at 6 weeks and 3 months postoperatively. Postoperative image findings (nerve root enhancement, nerve root thickening, displacement or compression of the nerve root, and residual mass size and signal) were assessed quantitatively. Inter-rater reliability was tested.
Results:
Inter-rater reliability between neuroradiologists was moderate for assessed MRI variables. In the immediate postoperative phase, compression or dislocation of the nerve root at the operated level was common. A residual mass at the operated level was seen in 80%, 47%, and 33% after 24 h, 6 weeks, and 3 months, respectively. Postoperative dislocation or compression of the nerve root from residual masses was seen in 67%, 24%, and 14% after 24 h, 6 weeks, and 3 months, respectively. A residual mass with a higher signal than muscle on T2-weighted images was seen in 80%, 30%, and 17% after 24 h, 6 weeks, and 3 months, respectively.
Conclusion:
A residual mass with compression or dislocation of the nerve root at the operated level, that disappears over 3 months, is a common MRI finding in patients successfully operated for symptomatic lumbar disc herniation. An expectant approach instead of early reoperations may perhaps be preferred in patients with residual pain and root compression due to residual masses with high T2-signal since these often seem to resolve spontaneously.
Level Of Evidence:
3.
Insights
Magnetic resonance imaging (MRI) after lumbar disc herniation surgery often shows residual masses that compress nerve roots. These findings commonly resolve within three months, suggesting an expectant approach for persistent symptoms.
Area of Science:
- Neurosurgery
- Radiology
- Spinal Imaging
Background:
- Post-surgical MRI interpretation for lumbar disc herniation can be challenging.
- Early postoperative MRI findings may not correlate with clinical outcomes.
Purpose of the Study:
- To characterize the natural evolution of magnetic resonance imaging (MRI) findings after successful microsurgical lumbar disc herniation removal.
- To assess serial MRI changes over three months post-surgery.
Main Methods:
- Prospective cohort study of 30 patients undergoing microsurgical lumbar disc herniation removal.
- Serial 3.0 T MRI scans performed within 24 hours, at 6 weeks, and 3 months postoperatively.
- Quantitative assessment of nerve root enhancement, thickening, compression, and residual mass characteristics.
Main Results:
- Moderate inter-rater reliability was observed for MRI variable assessment.
- Residual masses were present in 80% at 24 hours, decreasing to 33% at 3 months.
- Nerve root compression by residual masses decreased from 67% at 24 hours to 14% at 3 months.
- High T2-signal residual masses decreased from 80% at 24 hours to 17% at 3 months.
Conclusions:
- A transient residual mass compressing the nerve root is a common postoperative MRI finding after lumbar disc herniation surgery.
- These findings often resolve spontaneously within three months.
- An expectant management strategy may be appropriate for residual pain and root compression due to high T2-signal residual masses.
