Abstract: Objective To explore the mechanism of percutaneous laser disc decompression (PLDD) for treating prolapse of intervertebral disc. Methods 15 rabbits were divided into 3 groups randomly: sham group, model group with PLDD treatment, model group without PLDD treatment. The nerve conduction velocity (NCV) of L₆ nerve root and the activity of phospholipase A2 (PLA2) in the intervertebral disc of L₅-₆ were determined 2 weeks after the initial surgery. Results NCV in the group with PLDD was significantly faster than that in the group without PLDD (P<0.001); NCV in the group without PLDD was significantly lower than that in the sham group (P<0.001). The activity of PLA2 in the group with PLDD was significantly lower than that in the group without PLDD (P<0.001); The activity of PLA2 in the group without PLDD was significantly higher than that in the sham group (P<0.001). Conclusion The activity of PLA2 in the herniated discs is higher than that in normal discs, which result in NCV falls remarkably. The PLDD can reduces chemical factors such as PLA2.

Key words: prolapse of intervertebral disc, nucleus pulposus, percutaneous laser disc decompression (PLDD), phospholipase A2 (PLA2), nerve conduction velocity (NCV)