Objective To investigate the therapeutic efficacy of minimally invasive modified transforaminal lumbar interbody fusion (TLIF) combined with unilateral nail holding system in patients with extreme lateral lumbar disc herniation.Methods Thirty-eight patients with extreme lateral lumbar disc herniation were divided into minimally invasive modified TLIF combined with unilateral nail holding system group (observation group) and conventional open TLIF group (control group) with 19 cases each according to random digital table method.The therapeutic efficacy was compared between 2 groups.Results Surgery was completed successfully in 2 groups,and there was no perioperative complications.The amount of bleeding and hospital stay length in observation group were significantly less than those in control group:(152 ± 82) ml vs.(258 ± 104) ml and (6.5 ± 2.3) d vs.(12.7 ± 3.6) d,and the rate of fusion and score of Japan Orthopaedic Association 6 months after surgery in observation group were significantly higher than those in control group:18/19 vs.10/19 and (14.5 ± 2.1) scores vs.(12.6 ± 1.9) scores.There were statistical differences (P ＜ 0.01).There was no statistical difference in complications between 2 groups (P ＞ 0.05).Conclusion Minimally invasive modified TLIF combined with unilateral nail holding system in patients with extreme lateral lumbar disc herniation has less blood loss and shorter hospital stay,and it is effective and safe.