The heat is not high enough to destroy tissue. It just changes the mechanical properties of the cartilage and ligaments. The goal is to increase shoulder joint stability by tightening up the ligaments and capsule. This may keep the shoulder from dislocating.
RF heat used with disc protrusion is called nucleoplasty. The RF used is the same energy source used with thermal capsular shrinkage but it's high enough to destroy the tissue. A curved probe is advanced in and pulled out of the disc creating channels. As the probe goes forward, the tissue is heated and destroyed. Although the disc isn't being shrunk, removing some of the disc helps take pressure off the nerve.
Nucleoplasty using RF energy for the treatment of sciatica caused by disc protrusion is a fairly new procedure still undergoing study. It has been used successfully in patients with one or two small- to medium-sized disc protrusions with an intact annulus fibrosis. The annulus is the outer covering of the disc material.
Other, more conservative care is always advised first before having surgery of any kind. Physical therapy to correct posture and stretch the sciatic nerve and muscles around it should be part of the early treatment process. Many patients with sciatica have improved symptoms or complete resolution of pain without surgical intervention.