Pre-Test Optimizing Lumbar Discectomy: Closing Holes in the Disc Pre-Test Preserving disc material is beneficial in discectomy procedures, but increases the risk of reherniation and lower back pain. What mean increase in lower back pain was observed by McGirt, et al. (2009) after more than 2 years post-aggressive discectomy? 15.3% 20.2% 27.8% 34.4% According to 7 published studies on the use of bone-anchored implants for closing holes in the annulus, what was the average percentage reduction in reoperation for reherniation? 60% 72% 75% 81%