Stannard, 26, was rushed to hospital in Ypres after he crashed heavily into a deep ditch with around 70km to race.
Doctors diagnosed a fracture in one of Stannard's thoracic vertebrae, ending his hopes of becoming the first British rider to win Paris-Roubaix.
"I’ve hurt myself pretty badly before but straight away I knew I’d done something pretty bad. I was in a lot of pain," Stannard told Cycling Weekly.
"I’m pretty lucky to be honest – it could have been a lot worse."
Stannard, who took the best win of his career to date at Omloop Het Nieuwsblad last month, will now return home to await a specialist diagnosis before considering his return to the bike.
Team Sky's doctor Phil Riley said: “Ian has a fracture in one of his vertebrae as a result of his fall. The fracture is stable and he will undergo a review with a UK-based neurosurgeon this week, as well as having an MRI scan. That should allow us to find out more information following his CT scan.”
While his teammates, including Geraint Thomas and Bradley Wiggins, head to the Tour of Flanders and Paris-Roubaix, Stannard will turn his attention to the 2014 Tour de France, which starts in Leeds on July 5.
"It's going to really tough to get over, I’m pretty disappointed that I wont be there at Paris-Roubaix," Stannard added.
"But the Tour starts in Yorkshire this year and I’m a British rider, so I’m pretty sure I’ll be there. That gives me another focus and something to work towards."
Ian Stannard and Chris Sutton taken to hospital with injuries after four of Team Sky's riders crash in Ghent-Wevelgem
Ian Stannard becomes first British winner of Omloop Het Nieuwsblad after out-sprinting Greg Van Avermaet
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