<s>[INST] My 5 year old child just had her tonsils and adenoids and turbinate reduction surgery 5 months ago. We just had a cat scan done because she was no better and now cat scan shows she has very large adenoids and sinustitis. Can adenoids grow back this fast in a 5 year old or could the doctor have forgot to remove them during surgery? The doctor was done with her surgery in about 10 to 15 minutes which I thought was resly fast. [/INST] Hello, My answer is as follows:There are only few studies ad Chat Doctor.  The available information suggests that regrowth rate varies between 9% to 26%, but the regrowth usually is classified as "traces of adenoidal tissue" or "grade 1 - obstructing less than 33% of nasopharyngeal space". In this context, the conclusion is that adenoids rarely regrow and, when they do, usually their size is small or only traces, and asymptomatic. Please note that it is impossible to remove adenoids at 100% rate because this tissue is not encapsulated (contrary to tonsils); therefore, there is always the risk of adenoid regrowth. Literature suggests that adenoids' regrowth after adenoidectomy is significantly higher among child </s>