Board Thread:Manga/@comment-27321453-20180108221508/@comment-28958062-20180111111645

Helel ben Shahaar wrote:

As for the fact that Attack Titan was still standing even after his spine was pierced: please note that Eren never bothered to pull the spike out. Even though it has been established that titans cannot feel pain, having a spike of that size embeded into a body is a great hinder to movement (assuming it doesn't outright kill you).

My reasoning is that Eren purposely left the spike. Had he pulled it out, he would inevitably fall to the ground, and in those few seconds it took for his spine to grow back, Wilhelmina Tybur would have ground him to a dust so fine you couldn't even mix it into concrete. He used the spike as a pseudo-spine, a support for his body, until he could catch a breather from combat and grow back his real spine. That's a bit of a streched explanation but it kind of makes sense and gives me a bit of peace of mind, kind of wish Hange would pop out and fully explain that one.