Objective To verify the safety and effectiveness of a new percutaneous controllable curved plasma radiofrequency instrument for nucleus pulposus ablation. Methods A new percutaneous controllable curved plasma radiofrequency instrument were designed (controllable curved group), and its ablation effect was compared with the currently used straight head non-bendable plasma ablation instrument (non-bendable group) on gross specimens. The ablation instrument was placed through the right intervertebral foramen, and continuous ablation on the same intervertebral disc was conducted for three times. The ablation range and trajectory were recorded, and the temperature changes in the front, back, left, and right of the ablation center during and 15 seconds after ablation were monitored by the inserted temperature probe. Results There were no difference in temperature changes in the front, back, right regions of the ablation center during and 15 seconds after ablation between the two groups. The temperature changes in the left region of the ablation center both during and 15 seconds after 3rd ablation were larger than those in the non-bendable group (P＜0.01). Compared with the non-bendable group, the controllable curved group achieved angle control and larger single ablation area (2.282 5 mm² vs 1.135 8 mm², P＜0.000 1). Conclusions This new percutaneous controllable curved plasma ablation instrument can achieve angle control and ablation on the side opposite to the puncture site, increase ablation volume, and is safe.

A study of 10 cadavers and 100 CT scans of lumbar spine was performed to investigate the topographical anatomy of the posterolateral disc puncture in percutaneous lumbar discectomy.A way of the puncture at L_5-S_1 disc,with comparative plain films of lumbar spine in different positions were taken in 50 cases.The results showed that the pos- terolateral approach for percutaneous discectony was a safe way.However,it is important to have full knowledge of the regional topographical anatomy associated with the puncture tech- nique to avoid the potential neurovascular complications.The special position designed by authors for the puncture at L_5-S_1 disc is useful by lowering the position of iliac crest which hinders the entrance of needle,thus can raise the successful rate of the percutaneous discec- tomy 100% successful rate of the disc puncture at L_5-S_1 disc was obtained in 130 cases.The two puncture parameters of Chinese associated with percutaneous lumbar discectomy were first measured;and also the route including nearby structures,the complications were dis- cussed.