What did Gwen Stefani do to her nose bridge in your Professional opinion? Oesteotomies? Rhinoplasty? (Photos)

From her before and after photos it looks like she had osteotomies to narrow her nasal bones and tip refining by reduction of the nasal cartilage. 

Hello and thank you for your question. It is very difficult to make comments about what type of surgeries someone may or may not have had.  It would be much more helpful for you to have an in-person evaluation of your own nose.  Make sure you specifically look at before and after
pictures of real patients who have had this surgery performed by your surgeon
and not just a computer animation system. The most important
aspect is to find a surgeon you are comfortable with. I recommend that you seek
consultation with a qualified board-certified plastic surgeon who can evaluate
you in person.
Best wishes and good luck.
Richard G. Reish, M.D.
Harvard-trained plastic surgeon

The celebrity photos you posted appear to show a narrower appearance in her upper, middle, and lower thirds of her nose.  Based on your frontal photo, osteotomies and rhinoplasty surgery could be considered for achieving a narrower and less distracting nasal appearance. Hope this helps! Dr. Joseph. 

Based upon her photos, it looks like she had a rhinoplasty to narrow her bones and to refine her tip.

It looks like she has had osteotomies and her tip done. Although with makeup and lighting and photoshop its hard to say for sure.

When patients have a wide  bridge line, osteotomies are performed. This can be performed with a closed rhinoplasty approach with all of the incisions placed on the inside of the nose.  For more information and many before and after examples of narrowing wide nose   with osteotomies, please see the link and the video below