"Within 15 minutes of him coming off the field and assessing him, we realised that he was at risk of this particular rare condition. He was taken straight to Vincent Pallotti (Hospital) where he had a vascular surgeon waiting and he was operated on that night.
"It's very unusual, very rare but they had to cut through the muscle to release the pressure and they were only able to close that leg 10 days after his initial injury."
The team doctor said the Springboks' flanker was recovering and faces a lengthy break from the field. Super Rugby has currently been postponed due to the coronavirus outbreak.
Stormers coach John Dobson praised the team doctor's actions.
"Doc deserves enormous credit for Pieter-Steph, had a rugby player lost his leg it would have been devastating for the game. And if it wasn't for the timely intervention then I think (he could have lost his leg)... almost half of the 43 reported cases had resulted in that," Dobson said.