After local anesthesia, and the puncture point was 8-12cm on the side of the paraspinous process under C arm fluoroscopy. The needle was punctured though the skin with an angle of 45-60 to the posterior of the vertebral via "safe" entry zone to the herniated site outside the intervertebral disc under the epidural space. The syringe was drawn back to confirm that no blood or cerebrospinal fluid was flowing out, Contrast agents were injected to make sure no flows out of the spinal canal. 600 unit collagenase was dissolved in 2ml normal saline and injected slowly with rate of 1ml per minute. The needle was removed and keep the dorsal elevated position for 6-8 hours. Keep away from load bear of lumbar for 3 months.

For L1-L4 segment, percutaneous endoscopic transforaminal discectomy(PETD) will be performed. An 1cm length incision was made at 8-14cm lateral of the paraspinous process, where a needle puncture to the superior articular process of the lower involved vertebrae of the herniated disc. A series of conical rods are to be introduced, subsequently a reamer is to be introduced through the cannula. After removal of the disc herniation, the cannula and endoscope are to be removed. For L5/S1 segment, percutaneous endoscopic interlaminar discectomy(PEID) was performed. An incision of nearly 7 mm was made at the entry point of the skin, and a series of expansion channels were sequentially inserted into the surface of the ligamentum flavum.Then, the ligamentum flavum and soft tissue around it were removed. Then, the tongue of the working cannula was inserted and rotated into the lateral nerve root. Removed the prominent nucleus pulposus by various nucleus pulposus forceps.

After local anesthesia, and the puncture point was 8-12cm on the side of the paraspinous process under C arm fluoroscopy. The needle was punctured though the skin with an angle of 45-60 to the posterior of the vertebral via "safe" entry zone to the herniated site outside the intervertebral disc under the epidural space. The syringe was drawn back to confirm that no blood or cerebrospinal fluid was flowing out, Contrast agents were injected to make sure no flows out of the spinal canal. 600 unit collagenase was dissolved in 2ml normal saline and injected slowly with rate of 1ml per minute. The needle was removed and keep the dorsal elevated position for 6-8 hours. Keep away from load bear of lumbar for 3 months.

Visual Analogue Scale pain assess for leg. Use a ruler about 10cm long, one side is marked with "0" and the other "10" respectively. A score of 0 indicates no pain, 10 indicates the most unbearable pain.

Visual Analogue Scale pain assess for lumbar. Use a ruler about 10cm long, one side is marked with "0" and the other "10" respectively. A score of 0 indicates no pain, 10 indicates the most unbearable pain.

The percentage of disc herniation recurrence appearance. 0 represents the minimum and 100% represents the maximum.

The percentage of reoperation rate. 0 represents the minimum and 100% represents the maximum.

The Roland-Morris Disability Questionnaire is a health status measure designed to be completed by patients to assess physical disability due to low back pain. The lowest score is 0, the highest 24. The higher the score, the more severe the dysfunction.