Treatment for hypertrophic scars on chest

I have scars on my chest that is more than 10 years old. I’ve used silicone gel pads and some ointment with minimal success. I’ve been looking for clinics or hospital that speciliases on treatment hypertrophic scars.

I understand that from previous discussion with general practitioners, hypertrophic scars are difficult to successfully remove or make then flatter.

-What kind of procedures are available to get rid of these scars? 

-How long before results can be seen? 

– How much would this cost?