In addition to the concerns above, I would say also to be very careful about the stocks of saline you use and the needles you use. Make sure they are freshly opened, unused syringe needles (you probably already do this as you do needle play but I can't leave it unsaid just in case you don't or someone else reads this thread). The biggest risk is infection. Especially make sure that the sterile medical saline you use is in date and the package undamaged.

I would also do a check and make sure that the video was a genuine scene and not faked up with special effects. I have not heard of this before (though I have heard of inflating the penis... so it is not beyond possibility) so it may just be a fantasy made real by the magic of special effects.