• Change from baseline Oswestry disability index (ODI) [ Time Frame: 3, 6, and 12, months, and every year, up to 5 year after operation ]
  The ODI is based on a self-administered questionnaire measuring ''back-specific function.'' The questionnaire comprises 10 items, each with 6 levels of response. Each item is scored from 0 to 5, and the total summation is converted to a 0-100 scale. The ODI scores ranges from 0 to 100, with higher scores indicating severe symptoms.
• Change from baseline Visual Analog Pain Scale (VAS) [ Time Frame: 4, 8, 12, 24, 48 hours, 2 weeks, 3, 6, and 12, months, and every year, up to 5 year after operation ]
  VAS is a measurement score that indicates pain severity status. VAS score comprised a 10-cm line with ''none'' (0) on one end of the scale and ''disabling pain'' (10) on the other.
• Change from baseline EuroQoL-5 dimension (EQ-5D) value [ Time Frame: 3, 6, and 12, months, and every year, up to 5 year after operation ]
  EQ-5D is a standardized instrument developed by the EuroQol Group as a measure of health-related quality of life that can be used in a wide range of health conditions and treatments. The descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Rated level can be coded as a number 1 to 5, which indicates having no problems for 1, and having extreme problems for 5. As a result, a person's health status can be defined by a 5-digit number, ranging from 11111 (having no problems in all dimensions) to 55555 (having extreme problems in all dimensions). EQ-5D health states may be converted into a single index value. The index values are a major feature of the EQ-5D instrument, facilitating the calculation of quality-adjusted life years (QALYs) that are used to inform economic evaluations of health care interventions. The value sets are anchored on 11111 = 1 and 55555 = 0 and can therefore be used in QALY calculations.
• Change from baseline PainDETECT score [ Time Frame: 3, 6, and 12, months, and every year, up to 5 year after operation ]
  The painDETECT Questionnaire (PDQ) is a screening tool designed to detect neuropathic pain in patients with chronic low back pain (LBP) based on self-reported pain characteristics. The degree of the seven types of pain quality, the type of pain pattern, and the presence of radiating pain. From the three components of the PDQ, a total score is calculated; a high score indicates that the pain is likely to have a neuropathic component. Scoring is performed using a scoring manual, and results in a final screening score: a score of 0-12 indicates nociceptive pain, 19-38 indicates neuropathic pain, and 13-18 indicates mixed pain.
• Number of participants with treatment-related adverse events as assessed by CTCAE v4.0 [ Time Frame: up to 1 month after operation ]
  Surgery related adverse events (incidental durotomy, wound infection, re-operation, re-admission)
• Operation duration time (minutes) [ Time Frame: Immediate after operation ]
  Intraoperative time in minutes
• Volume of postoperative drainage (ml) [ Time Frame: Within 3 days after operation ]
  Total drainage after surgery in milli-liter
• Number of participants with complete discectomy [ Time Frame: Within 3 days after operation ]
  After surgery, degree of discectomy was measured using postoperative MRI
• Concentration of creatine phosphokinase level in blood [ Time Frame: At 2 day after surgery ]
  Creatine phosphokinase assessment to measure muscle injury at operation
• Volume of postoperative Fentanyl consumption [ Time Frame: At 3 days after operation ]
  Total amount of fentanyl consumption after surgery (PCA dose + rescue dose)
• Times of hospital stay (hours) [ Time Frame: Within 7 days after operation ]
  Total hospital stay after surgery
• Number of radiographic complications [ Time Frame: every year, up to 5 year after operation ]
  Radiographic complications includes disc degeneration, facet degeneration, re-ruptured disc, back muscle atrophy, kyphotic change, disc rupture...

• Procedure: Biportal endoscopy
  Biportal endoscopic spine surgery (BESS)
• Procedure: Microdiscectomy
  Using microscope for discectomy

• Experimental: Biportal endoscopic discectomy
  Biportal endoscopic discectomy for lumbar herniated intervertebral disc
  Intervention: Procedure: Biportal endoscopy
• Active Comparator: Microdiscectomy
  Microdiscectomy for lumbar herniated intervertebral disc
  Intervention: Procedure: Microdiscectomy

Inclusion Criteria:

• patients aged between 20 and 80
• patients who has radiating pain (VAS >=40) on lower extremities with HIVD
• patients who required one-level discectomy between L1 and S1
• those who (only if a signature was obtainable), or whose legal guardian, fully understood the clinical trial details and signed the informed consent form

Exclusion Criteria:

• Revision surgery
• Over spondylolisthesis Gr II
• Degenerative lumbar scoliosis (Cobb angle >20)
• patients with a history of other spinal diseases (compression fracture, spondylitis, tumor)
• women with positive pregnancy tests before the trial or who planned to become pregnant within the following 3 years
• patients with a history of malignant tumor or malignant diseases (but the cases of cured disease with no relapse for the past 5 years were included in the present study)
• patients with mental retardation or whose parents or legal guardians were older or had mental disabilities
• other patients viewed as inappropriate by the staff