Hi, DS(4) has laryngotrachaeomalacia.
Have they considered trachea as well as laryngomalacia? That will lead to breathing difficulties. Trachaeomalacia means the trachea is floppy as well as the larynx. Some babies have both issues. DS had larygomalacia diagnosed in a bronchoscopy and annoyingly it was a different consultant doing the surgery to the one who knew DS's symptoms really well. The surgeon assumed the larynx accounted for all symptoms so didn't fully investigate further. DS' consultant wanted to go back in to check the trachea.
Have they checked for other issues as well? With a likely diagnosis of laryngomalacia and trachaelmalacia DS was checked for Primary Ciliary Dyskinesia, every form of Cystic Fibrosis and a few more diseases I can't even recall. His symptoms got a lot worse with infections and he got a lot of infections. He turned out to have okish cilia, so they weren't working brilliantly, but just within normal. His immune system was also tested, and was at the low end of normal. Also had tiny nasal passages, allergies and asthmas, so his symptoms were a sort of perfect storm of laryngotrachaelmalacia + various other milder issues.
Could swelling from the procedure be an issue?
Did they do a lung wash to see what bacteria were lurking down there? We had a few, including a multi-resistant pathogen.
We had a difficult few years, but at age 4 DS is doing a lot better, though we still hold emergency ABs for him and have to nurse him through colds and flu. The cartilage stiffens over time, and by 1.5 yrs there was already a significant improvement.
That's all I can think of, and the suggestions above may not fit with how your baby is presenting, so the consultants may already have discounted them.
Who is your consultant? We had an incredible consultant in paediatric respiratory, at the regions respiratory specialist unit.