Surprisingly, he doesn't.
I forgot to mention that the OAV has so many plot loopholes, it's ridiculous.
SPOILER ALERT! Ah, screw it! No one's gonna watch this, anyway.
During the final battle between Shishimaru and Ginnai, Shishimaru has his right forearm chopped off. He then slices Ginnai in half, rupturing his hydrogen fuel cell and setting off an explosion that decimates at least 30 city blocks.
The next scene has Shishimaru, Momoji and Hayabusa lying on the ground. Shishimaru wakes up and sees faint, ghost-like images. The images tell him they saved him and his comrades from the explosion, and that there are more battles to come. The larger apparition mentions his name as "Black Lion" before disappearing. Shishimaru then sees a giant spaceship hovering over the sky. He then tries to reach out for it with his right hand.
That's when the narrator says, "At this point, Shishimaru did not notice that his right arm, which was severed by Ginnai in the battle, was reattached."
Sequel!!