Is it better to remove implants through the areola which is my original scar, or underneath the breast?

You can have the implants removed through the original areola incision or under the breast.  As long as you are a candidate and the surgeon is comfortable with either approach, then the choice is yours.  Good luck with surgery!

Yes, implants can be inserted through areola scars and of course, if your surgeon can remove the implants through the initial scar that will provide better visual results.

The
removal of 300 cc implants will change the volume of the breasts significantly
creating sagging.  A loose skin envelope may
require skin excision.  For minor skin
excision, a circumareola approach is best. 
The implants can be removed through the incision and the skin can be
tightened.  If you need a greater skin excision,
you will benefit from an inframammary incision using The Bellesoma Method.  Best Wishes,Gary Horndeski, M.D.

For implants that have been in for several years, I would recommend removing the capsule with the implant.  This is better performed through an incision in your breast fold.  

If you are simply having the implants replaced, going back through the areola is possible so that you dont add new scars onto the breasts. If you are putting new implants in, i would suggest a new incision due to the risk of bacterial contamination of a new implant through the nipple and the risks of capsular contracture