Which method is used to treat a double layer herniated disk?

Depends: The term "double layer herniated disk" is not commonly used. Terms commonly used are contained, extruded, and sequestered. In cases with a disc recurrence after surgery, the MRI may show the new herniation encased in post-operative scar (a two layer effect). The treatment for each of these pathologies may vary depending on symptoms and the anatomy.

Not a common term : This term is not routinely used to describe disc herniations.

Not clear on ?: Sorry I am not sure what a double layer herniated disc is. In general, for one level or multiple level disc herniations, treatments consist of medications, physical therapy and injections first. If the disc location explains the pain (correct side, correct part of leg), and pain is severe, associated with weakness, bowel or bladder problems, then surgery should be considered.