He was able to conduct the post-fight interview but around 15 minutes later complained of head pains as he was preparing to take a shower.
MacKinnon underwent the emergency procedure and Reinsfield said the prognosis afterwards "leans on the positive side".
"He's doing better this morning than he was last night," he said. Berridge's cousin and Wanganui trainer Paul Berridge was in the corner and saw the toll that was taken.
"You could really see the devastation when Dan walked over to congratulate him.
"He looked really fragile and he looked like he hadn't recovered."
Robert Berridge had dictated the pace in the early rounds although he couldn't connect with the big knockout shot he wanted, before MacKinnon made a comeback in the sixth, knocking his stronger opponent into the ropes.
By the seventh round, MacKinnon was split open above the right eye from a close quarters head clash and then Berridge caught up with him in the eighth, clipping him with a shot that sent MacKinnon down to a knee.
The ninth round was a barnstormer as MacKinnon put Berridge down, but he climbed up to unload with vicious combinations which in turn dropped MacKinnon, who somehow pulled himself back up.
"They both looked pretty gassed by the end of the ninth, but Robbie just stepped up another gear," said Paul Berridge.
"Robbie kept on to turn him away to get free so he could get some combinations."
Looking tired himself, Berridge dropped MacKinnon again and while he staggered back up, the "cement" in the left hand of Berridge saw the fight stopped with seconds left in the tenth.
Duco Events is in talks to bring multiple-time world champion Roy Jones Jr to New Zealand to fight "the Butcher" next.
"Now that David Tua's had his swansong and he's retired, Duco's main focus is Robbie and Joseph [Parker]," said Paul Berridge. "[Commentator] Bob Sheridan was saying it was the best fight of the year and he's going to vote on it when he gets back to Las Vegas."