Fatialofa, 27, a former New Zealand Schools' representative, took a blow to his neck only a minute after entering the field as a substitute in Worcester's 5-62 loss to Saracens at the weekend.
He was left with reduced power and sensation in his arms and legs.
Scans revealed no broken bones but showed some bruising and swelling on his spinal cord.
Surgery was expected on Monday evening, (UK time) with an aim of relieving the pressure caused by the bruising and to help restore function.
Worcester Rugby said in a statement that Fatialofa was fully awake and alert and had the support of family.
"Nick Tait, Warriors' club doctor, and the club's medical team are in daily contact with Michael's neurosurgeon.
"Michael and his wife, Tatiana, have been overwhelmed by messages and offers of support from the rugby community across the world," the club said.
Fatialofa's wife said in a message: "Haven't had a chance to reply to a single person yet but Michael is overwhelmed (in the best way) by all the prayers and support – it's truly keeping his spirits high.
"[We're] honestly just so thankful for the outpouring of love!
"We can tangibly feel the presence of God enveloping us in this horrible situation and have such trust he is good through it all.
"Update wise: Michael is stable in intensive care right now. [Please] keep praying for any improvement. Love, the Fats."
Warriors director of rugby Alan Solomons said after the game it appeared Fatialofa had dropped his head as he went into contact and the injury was 'a massive concern'.