Changes of MRI in Inter-Spinal Distraction Fusion for Lumbar Degenerative Disease: A Retrospective Analysis Covering 3 Years

OBJECTIVE:To assess the preoperative and postoperative changes in MRI image and the short-term efficacy of the ISDF with BacFuse covering 3 years. METHODS:32 patients who underwent ISDF were involved in this retrospective study. The symptoms assessment including VAS, ODI, and SF-12 were evaluated preoperative and postoperative at 1 year and 3 years. The X-ray was used to measure posterior disk height (PDH), foramina height (FH), foramina width (FW), and MRI was taken to assess the cross-sectional area of dura sac (CSADS), cross-sectional area of canal (CSAC), herniated disc area, ligamentum flavum area. The preoperative ratio of herniated disc area and ligamentum flavum area to CSAC were compared with post-operative ratio. The modified Pfirrmann grade system was used to assess the surgical lumbar disc. RESULTS:The symptom indexes were significantly improved after surgery. PDH and FH increased significantly (P < 0.05) after surgery compared with that before surgery, but there was no statistical difference in FW (P > 0.05). CSADS and CSAC increased obviously (P < 0.05), while the area of herniated disc and ligamentum flavum decreased significantly (P < 0.05). The ratio changes showed a significant difference between last follow-up and pre-operation (P < 0.05), but there was no statistical significance in grade changes of surgical disc. CONCLUSION:ISDF with BacFuse could relieve clinical symptoms and expanse the spinal canal area in MRI. During 3-year observation, it could provide continuous traction and maintain the area of spinal canal, so as to partially retract the herniated disc and make it possible to repair the disc.