Microinvasive Endoscopic Discectomy (MED) is one of the minimally invasive treatments for lumbar disc herniation. As with traditional open disc removal, there is a certain recurrence rate after surgery. In China, recurrent LDH refers to the recurrence of symptoms after lumbar disc herniation surgery, and imaging shows herniation. According to foreign scholars, recurrence after disc removal is defined as symptom-free for at least 6 months after surgery, with a herniated disc in the same segment that had been previously operated on [1]. The recurrence rate after nucleus pulposus removal is approximately 4% to 11% [1,2]. In this paper, we summarize 73 cases of symptomatic recurrence after 1276 cases of LDH treated by MED in our hospital from January 2001 to January 2006, analyze the reasons for their recurrence, and discuss their reoperation strategies. 1 .Data and Methods 1.1 General Data From January 2001 to January 2006, there were 1276 cases of single-segment LDH diagnosed by clinical examination and CT/MRI and treated with MED. There were 697 male cases and 579 female cases, with ages ranging from 14 to 60 years, and an average of 37.2 years. The duration of the disease ranged from 4 months to 10 years, with an average of 7 months. All patients had obvious symptoms of low back and leg pain. Clinical examination: 1,174 cases of pressure pain or radiating pain in the spinous processes of the corresponding segments, 831 cases of hyperalgesia in the lower calf and/or dorsum of the foot, 837 cases of hypesthesia of the extensor [muscle], 372 cases of hyporeflexia or disappearance of the Achilles tendon reflex, and 866 cases of a positive straight-leg raising test or a positive femoral nerve pulling test. Lesion segments: L4/5 852 cases, L5S1 401 cases, L3/423 cases. Type of herniation: 914 cases of lateral type, 73 cases of central type, 289 cases of paracentral type, of which 319 cases were combined with lateral saphenous fossa stenosis and 92 cases of ossification of herniation. Epidural anesthesia, prone position and MED were used. Postoperatively, the patients were treated with routine infection prevention, anti-inflammation, dehydration and symptomatic treatment. Outpatient follow-up after discharge from the hospital, the average 39.2 months (8-60 months), 1059 cases were followed up. 1,2 Inclusion criteria: selection criteria were age 60 years,single-segment disc herniation,no history of lumbar surgery;all cases were diagnosed by CT/MRI confirmation and ineffective conservative treatment for more than 3 months. 1.3 Exclusion criteria: lumbar spinal stenosis, lumbar spine tumor, tuberculosis, lumbar spondylolisthesis, intervertebral instability, history of lumbar spine fracture, multisegmental disc herniation, bilateral disc herniation, extreme lateral type, giant free type herniation, and history of lumbar surgery. 1,4 Efficacy evaluation criteria: modified Macnab efficacy evaluation criteria Excellent: pain disappears, no motor dysfunction, resume work and activities; good: occasional pain, main symptoms disappear, muscle strength is normal, straight leg raising test (-), can engage in light physical work; OK: symptoms have improved, but still have pain, can not work; poor: there is a manifestation of nerve compression, need to be further surgical treatment.