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

OBJECTIVE: Muscle injury is inevitable during surgical exposure of the spine. This study compared paraspinal muscle injury after 4 surgical techniques: microdiscectomy (MD), percutaneous endoscopic lumbar discectomy (PELD), percutaneous endoscopic interlaminar discectomy (PEID), unilateral biportal endoscopic discectomy (UBED). METHODS: Eighty patients who underwent MD, PELD, PEID, and UBED were prospectively observed. Creatine phosphokinase (CPK) and C-reactive protein levels were measured on admission and postoperative days 1, 3, 5, and 7. CPK ratio was calculated as CPK on postoperative day 1/CPK on admission. Cross-sectional area of the high-intensity lesion in the paraspinal muscle was measured on magnetic resonance imaging after surgery. Operative time and hospital stay duration were also examined. Clinical outcome was evaluated using the visual analog scale for back and leg pain. RESULTS: MD group had the highest CPK levels on postoperative days 1 and 3 and CPK ratio (P < 0.01, P = 0.02, P = 0.04). Serial C-reactive protein levels were highest in MD group (P < 0.01). PELD and PEID groups had lower C-reactive protein level on postoperative day 1 than UBED group. MD group had largest cross-sectional area (P< 0.01). Cross-sectional area was larger in UBED group than in PELD and PEID groups (P< 0.01). Operative time and hospital stay duration were shortest in PELD group (P< 0.01, P< 0.01). MD group had significantly higher visual analog scale scores for back pain on postoperative days 1 and 3 than the other groups (P< 0.01, P = 0.02). CONCLUSIONS: PELD is the least invasive spinal surgical technique.