Randomized, placebo-controlled, double-blind comparative study of N-Acetylcysteine for the treatment with intervertebral disc degeneration

INTERVENTION: Oral administration of NAC (900mg/day, 6 months) Oral administration of placebo CONDITION: Lumbar intervertebral disc degeneration associated with low back pain (containing lumbar disc herniation) PRIMARY OUTCOME: Quantitative assessment of disc degeneration using Q‐space imaging. INCLUSION CRITERIA: All participants who agree with enrollment in this study and meet all the criteria as bellows; 1) Lumbar intervertebral disc degeneration (Phirrmann grade : 3, 4) or lumbar disc herniation in whom VAS score is over 5.0 point. 2) Regardless of patients with hospitalized or outpatinet. 3) Regardless of disease with primary or recurrence. 4) Agreement to stop anti‐inflammatory analgesic except for an approved medicine.