Thank you for your question.
ACDF stands for ANTERIOR Cervical Discectomy and Fusion
. So it is an anterior procedure. I think both your surgeons mean the same that they want to approach the problem from front. The incision for this will be on either left or right side of the midline. Technically this is a correct approach for a single level stenosis. Another approach used is posterior (back of neck) approach that is generally useful to address multilevel stenosis.
Hope this answers your query. Please let me know if I can be of further assistance.