A 42-year-old male presented with bilateral posterior sciatica having lasted for 2 years. The pain in the right side was greater than the pain in the left side.

The VAS was 9/10 for right leg pain and 3 to 4/10 for left leg pain.

MRI views showed a central disk herniation at the L4-L5 level. A CT scan also showed a soft disk ( Fig. 18.72 ).

Axial MRI images are used to determine the target point, the intended needle trajectory, and the distance from the midline. In this case the distance from the midline is ~12 cm ( Fig. 18.73 ).

The needle trajectory in this case required a shallower angle than other herniations to reach the contralateral side and perform a complete midline decompression ( Fig. 18.74A,B ).

Diskography is then performed ( Fig. 18.74C,D ).

The final working channel position is at the medial pedicular line on the AP view and half anterior and half posterior to the posterior border in the lateral fluoroscopic view ( Fig. 18.74E,F ).

Upon introduction of the endoscope, the blue-stained disk fragment can be seen ( Fig. 18.75A ).

As the endoscope is advanced, the annulus and soft tissue can be seen ( Fig. 18.75B ).

The radiofrequency probe is then used to ablate the PLL and annulus ( Fig. 18.75C ).

The remaining disk fragment can be visualized after laser ablation is complete ( Fig. 18.75D ).

The ventral dura and PLL are seen ( Fig. 18.75E ).

The dural sac is decompressed ( Fig. 18.75F ).

Adequate decompression is confirmed by the ventral dural pulsation and free nerve root as seen in Fig. 18.75G .