Can the "base" of the nose bridge be narrowed?

Hello and thank you for your question.  The best advice you can
receive is from an in-person consultation.  It is certainly possible to narrow the nasal bone as you describe.   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

Actually, that maneouver (nasal base narrowing) is essential part of the so-called "basic rhinoplasty", namely a pack of surgical gestures applicable to those standard cases of nasal surgery.It is achieved by splitting the nasal bones at the dorsum, where they meet and get fusion, by means of dorsal shaving or, if no hump existed, by means of paramedial osteotomies, and once the bones are freed at the dorsum the surgeon applies the basal osteotomies or infractures at Joseph's angle (the angle between maxilla and nasal bones) so that they stay well concealed and no step is seen at the walls of the nose.One common issue in rhinoplasty revisions is the unexplainable abscense of osteotomies in cases which they were a must.