Abstract:[Objective] To compare the clinical outcomes of PELD and MED for revision surgery for recurrent herniation after percutaneous endoscopic lumbar discectomy.[Methods] A retrospective study was conducted on 57 patients who underwentsurgical treatment for recurrent herniation after percutaneous endoscopic lumbar discectomy from March 2012 to October 2017. Of them, 30 patients received PELD, while the other 27 patients had MED. The length of the incision,operation time, blood loss, frequency of radiation perspective, hospital stay, hospital costs were compared between the two groups. Their clinical outcomes were evaluate with Visual Analogue Scale (VAS),Oswestry Disability Index (ODI) and modified MacNab’s criteria. [Results] The PELD group had significantly shorter incision length,less blood loss, longer X-ray exposure than the MED group (P<0.05).There was no significant difference in operation time,hospital stay and hospital costs between the two groups(>0.05)．Both VAS and ODI in the two groups significantly improved after operation compared with those before operation (P<0.05).The VAS for the lower back and ODI were significantly higher in the MED group than PELD group at 3 days after surgery (P<0.05),and no significant difference was found in VAS for the leg(P<0.05). In both the PELD and MED groups, VAS and ODI at pre-operative,3 and 6 months and at the final follow-up after surgery was no significant difference (P<0.05).At final follow-up, based on the modified MacNab standard, it was excellent in 22 cases, good in 5 cases, fair in 2 case,poor in1 case in PELD group; it was excellent in 22 cases, good in 3 cases, fair in 1 case ,poor in 1 case in MED group. Excellent rate of the PELD group was 90.00%, and that was 92.59% in the MED group, there was no significant difference between the two groups(P>0.05).[Conclusion] We found that PELD equals MED for the relief of radicular pain for recurrent herniation after PELD, but PELD is more advantageous for lower back pain than MED in a short period of time. The PELD had significantly shorter incision length and less blood loss than the MED.Howerer,the MED had significantly shorter X-ray exposure than the PELD .