I would suggest reading the definitions. See pgs 2-4 here:
https://www.ama-assn.org/system/files/cpt-corrections-errata-2021.pdf
Acute, uncomplicated illness or injury: A recent or new short-term problem with low risk of morbidity for which treatment is considered. There is little to no risk of mortality with treatment, and full recovery without functional impairment is expected. A problem that is normally self-limited or minor but is not resolving consistent with a definite and prescribed course is an acute, uncomplicated illness.
Examples may include cystitis, allergic rhinitis, or a simple sprain.
Acute illness with systemic symptoms: An illness that causes systemic symptoms and has a high risk of morbidity without treatment. For systemic general symptoms, such as fever, body aches, or fatigue in a minor illness that may be treated to alleviate symptoms, shorten the course of illness, or to prevent complications, see the definitions for self-limited or minor problem or acute, uncomplicated illness or injury. Systemic symptoms may not be general but may be single system.
Examples may include pyelonephritis, pneumonitis, or colitis.
Consider instead: Chronic illness with exacerbation, progression, or side effects of treatment: A chronic illness that is acutely worsening, poorly controlled, or progressing with an intent to control progression and requiring additional supportive care or requiring attention to treatment for side effects but that does not require consideration of hospital level of care.
I would consider spondylosis chronic and if they are having unmanageable pain or other issues (radiculopathy) it would be chronic w/ exacerbation in my opinion. They tried tylenol or ibuprofen & heat w/ topical creams and maybe therapy but that is not working anymore and they are being referred to physiatry for example.)