Comparison of Surgical Invasiveness Between Microdiscectomy and 3 Different Endoscopic Discectomy Techniques for Lumbar Disc Herniation

•Iatrogenic muscle injury was compared among 4 surgical techniques, MD, PELD, PEID, and UBED.•Surgical invasiveness was compared using blood markers and postoperative MRI.•MD had the highest CPK and CRP levels and largest CSA of the high-intensity lesion in the paraspinal muscle after surgery.•Surgical invasiveness affects hospital stay duration and postoperative back pain in the early stage.•PELD caused the least muscle injury and reduced postoperative back pain and hospital stay duration.