The empty chair is one gestalt method, probably the most well-known, but certainly is not required to do gestalt therapy. My T has a strong background in Gestalt and has asked me if I was interested in the empty chair a couple times, but it never seemed to be the 'right' thing.

My typical experience of a gestalt trauma processing...
I start talking about the trauma and when I get to a pause, T will ask what I'm feeling right NOW. He might ask how my body is feeling, if there is any tension anywhere? I would then make an effort to focus on my physical body in the present moment and see how it is reacting. I might then describe a tightness in my neck, and T will try to keep me focused on just staying *with* this feeling...describing it more. I might then say 'it feels like I cannot speak, like my neck is so tight no words can come out...or it reminds me of X time...etc.'

When I end up being able to focus on how I am feeling and my body is responding in the NOW of the therapy room, it helps me to bring myself out of living in the past of the trauma and focusing on what I can do right now. It has also taught me just how much the unresolved trauma is a part of my everyday life, whether I wanted to admit it or not.

It has also helped me to identify feelings better by being more in touch with my body. For example, I might at some other point feel that tightness in my neck and I know it is an emotional response. Just having that awareness is extremely powerful for learning when I am being triggered and how I can focus on the NOW and allow the emotional wave to pass.

I can only speak for myself, but I think the gestalt techniques were very helpful in processing trauma...and I never did talk to an empty chair.