Both are dangerous. Both are good, short term, for non-
DDD related singular disk issues. Both are bad, for
DDD, or anything involving narrowing of the spinal canal. Also, manipulations can increase rate of degeneration in the vertebrae.
What's important here, is the rate of degeneration. Most likely, your NS doesn't know that now? They will watch you, and over time, get a decent judge of the rate.
Start taking steps to reduce the rate of degeneration.