Post-decompression Disc Herniation - A More Common Complication. Comparison Between Minimally Invasive and "Mini-Open" Techniques

Background Index level disc herniation following lumbar spinal decompression is somewhat overlooked as postoperative complication, resulting in return of symptoms. It is proposed that the combination of local instability and degenerated disc is more likely to result in disc herniation. There is no literature comparing post-decompression disc herniation rates between different techniques. Purpose This study compares the postoperative disc herniation rates of the "mini-open" laminectomy versus the tubular system decompression. Study Design/Setting Retrospective comparative study Patient Sample 563 patients who underwent primary lumbar spinal decompression in our institution between February 2015 until September 2020. Outcome Measures Primary: comparison of post-decompression surgery, index level, disc herniation occurrence between two surgical techniques. Methods Patient files were retrospectively reviewed and divided into two groups, distinguished by surgical technique, "mini-open" partial laminotomy and minimally invasive surgery using tubular system. Demographic, clinical, and postoperative data were collected and compared using independent two-tailed t-test and Fisher's exact test with significance set at p<0.05. Results Postoperative index level disc herniation was significantly lower in the minimally invasive surgery group with 2 cases (0.8%) versus 19 cases (5.8%) in the "mini-open" group [p=0.002]. Disc herniation following single level and multi-level operations were also significantly lower in the minimally invasive group compared with the "mini-open" group (2 versus 11 and 0 versus 8 respectively; p<0.05). Conclusion Postoperative index level disc herniation following lumbar spinal decompression occurs in 3.7% of surgeries. Minimally invasive surgery is found to result in less herniations then "mini-open".