Ken, from ONZ, works for Dr. Bierstedt. Many of Dr. Bierstedt's team members are former employees/patients of Dr. Ritter-Lang. They are correct, at least from what I've heard, that Dr. Ritter-Lang and Stenum are not good. However, they will say anything to prevent you from going to a surgeon outside of ONZ. Let's face it, they are sales people too.
Dr. Clavel is only associated with Dr. Bierstedt for marketing purposes. If you tried to get an appointment with Dr. Clavel through Dr. Ritter-Lang's website, they would push you to go with Dr. Ritter-Lang. Dr. Clavel has his own site. Here is a link to it:
Barcelona Spine Center
Btw, I believe the physicians at ONZ are very good. However, IMO, it is very shady of Ken and the team leaders to say that Dr. Clavel is associated with Dr. Ritter-Lang, when he has nothing to do with him except for appearing on his website. These people (i.e. Ken, Malte, Kelli) on the ONZ team are more closely related to Ritter-Lang and Stenum than Dr. Clavel ever was or will be.
Good luck!!
Gene