I do not know what Prof Zamboni was thinking when he made this recommendation. For me the logic of staying with DMT/CRAB drugs is this:
1 - MS may be a combination of vascular and immune system problems, so we may need to treat both. An unknown at this time.
2 - Stopping a drug which is helping the patient is considered risky by medics, pharmacists etc.
The most compelling reason to continue everything as before procedure is continuity.
Not so much continuity of drugs etc but to monitor improvements/regression with a known datum.
If you have the procedure then stop taking the drugs you've been on for X number of years - how can you attribute any changes (good or bad) to what's been undertaken.