Pretty sure you have to pull the rear seat back.
It might be easier to leave the trunk down and do the job from inside if possible to keep everything lined up.

 

I like to know the answer too.

 

Dealing with the same issue except my hinge is completely broke

 

Mine has broke 3 times now on my 2006 Avalon, due to a bad design on the driver-side hinge using 14ga steel to hold the tension bar, IMHO. The tension bar causes the steel bracket to rip open, allowing the tension bar to come off. Replacing is tedious, requiring the back seat to be removed as well as the rear deck covering, to be able to get to the bolts securing the hinge. Also, the torsion bars, if they haven't popped-off already, must be removed. Without the torsion bars, the trunk won't stay up, and must be propped open. There is also a wiring harness going up into the lid and other things that must be removed, before the trunk lid can be lifted off (two people job). The new hinge can be modified by welding another small piece of 14ga steel on the inside of the bracket holding the torsion spring. This should have been a factory recall! Overall, it will cost over $200 to have a dealer make the repair, special tools required, of course.