Volumetric measurement of herniated disc material as a predictor of outcome in periradicular therapy.

Purpose: The aim of this study was to analyze the correlation between volume change in disc herniations and pain improvement after CT guided periradicular therapy.

Methods: Between 5/2017 and 9/2023 46 volumetric MRI examinations of 18 patients suffering from lower back pain were compared to a control group, prior to and following periradicular infiltration therapy. The performed procedure included an image guided application of a glucocorticoid, a local anesthetic and a contrast agent close to the affected nerve root. An additional 3D MRI-dataset was acquired to perform the volumetric analysis. The measurement was conducted using a manual 3D tool independently by two experienced physicians twice. For measurement and calculation of correlation, the average value of the four measurements per examination was used. We assessed the volume-change of the herniated discs in follow-up examinations in both groups as well as change of pain score under and without therapy.

Results: Under interventional pain therapy, the herniated disc volume was significantly reduced compared to the control group. In the intervention group, the disc volume was reduced by an average of 20,4% whereas the disc volume in the control group increased by an average of 33,6%. There was an improvement of pain score of 4.4 points in the intervention group whereas the control group showed a worsening of 1.2 points.

Conclusion: Periradicular CT-guided infiltration leads to significant volume reduction of herniated discs compared to non-treated patients. Furthermore, a correlation between change of volume of the herniated disc and an improvement of pain score over time could be observed.