ICD-10 Burn Coding

Some of us at work were doing one of the ICD-10 refresher webinars offered by AAPC. We were doing the sepsis webinar and disagreed with AAPC about the answer in one of the examples; I e-mailed AAPC, but I thought I'd see what you guys think.

Example: A consultation is requested for a patient with third degree burns to his entire back that has developed sepsis.

Our answer:

T21.33XA for the 3rd degree burn of the upper back

T21.34XA to account for the 3rd degree burn of the lower back

T31.11 to account for the percentage

A41.9 for the sepsis

AAPC's answer was T21.33XA for the burn, and the rest the same.

Our issue is with the burn code. Since the example specified the entire back and there is no code for the entire back, would we not need both codes? The index in ICD-10 -- at least, in my copy, which is the AAPC book -- does have a code for burns to "back (lower)", but that defaults to the lower back code, which again differs from the correct answer in the webinar.

Opinions?

Thanks!

ICD-10 Burn Coding