You can do it with Poser and some other apps to edit the video.
But if you don't know what you do it will be no fun.

Take an simple human figure that comes with poser and apply some pose to it at maybe frame 30. Then go through the frames and do fixes to the pose if needed. (to avoid abrupt changes in pose)
Go to frame 60 and apply another pose to the figure, check the interpolation again and make movie at very low resolution.

Thats the easy part about it. The problematic part would be the animation of the surgery.
Prolly there is no way around modeling and painting skills to let it appear realistic compared to the standard figures.Even after a few weeks practise and with very good skills it would be difficult as soon as you reach the point where you have to create your own content.
Besides this, the movie with 60 frames will need quite some time to render on a high end machine. The movie of this site you refer to would take really long to render with high quality and acceptable resolution. 320x240 is not the way.

So... In the end it's not a good task to start with if not familar with the software you are using or will have to use.

That's my opinion. I wish you good luck tho. :)