Preliminary Points
• The patients position and complications are the same as for the L5 – S1 approach
• You have to evaluate the width of the foramen and the best angle to extract the hernia without wounding the dura mater. Indeed, if the foramen is large, you can penetrate the dura inadvertently.

Techniques
An L4 – L5 hernia is not usually difficult to operate.
Sometimes, it can prove difficult in the case of pusillanimous patients. In this case, you must take more time to obtain a more efficient effect with the sedation. The hernia can be almost excluded in the medullar channel and then you have to penetrate the foramen at 70 degrees from the sagittal plane, as in the case of an L5 – S1. The triangular working zone can be small, and you have to be very careful when passing along the exiting root so you do not wound it (see recommendations in previous chapter). Sometimes, you can insert a trephine to abrase the anterior side of the facet (posterior side of the foramen) and then take out the hernia. Sometimes, you get a big fragment of two colors : blue for the side inside the disk and white or red for the side in the epidural space. More often you do not immediately find this big fragment and you have to look for it in the epidural space by using the endoscope. An enormous articular facet can be difficult to abrase or pass around. You have to persevere in reaching the hernia.

Tricks Concerning the Instruments
You should check the quality of the forceps. Some manufacturers make forceps with one of the jaws which opens at 70 degrees. This makes it easier to clasp a hernia and to pull on it in the epidural space.