InHealth has backed out of the proposals which would have led to the closure of the two departments, one at Leigh Infirmary and and the other at Wrightington hospital.
Staff could have been redeployed or made redundant if the project had gone ahead to move the entire department to a super sterilisation centre 10 miles away at Euxton Hall Hospital in Chorley.
Surgical instruments from five hospitals across the North West would have been cleaned at the InHealth site but it will now remain within the NHS.
Unison has expressed its relief that plans are no longer going to go ahead, saying that it would have put jobs and lives at risk.
Stephanie Thomas, head of health for Unison North West said: "We believe this risked severe delays in operations, and the damage or contamination of
equipment in transit.
"Our campaign was particularly supported by those staff who actually do the operations including consultants. We will now refocus our campaign to
support our preferred option of building a fit for purpose provision at Broad Green Hospital."
A spokeswoman for Wrightington, Wigan and Leigh NHS Trust confirmed that InHealth has walked away from negotiations but that they were continuing to explore other options.
Unison's campaign was on a large scale, amid fears that the service supplied to patients would suffer. There were fears that operations could be delayed because the essential equipment was not on site.
Ms Thomas said: "Unison locally have worked well to save this service. Our activists have marched, leafleted and petitioned the public and produced their own leaflet, which was circulated to the local MPs and councillors, the media, hospital consultants and copies were also sent to "In Health".
"Staff at the separate sites work under the NHS and know the doctors and surgeons.
"They know what equipment suits them best and if the different units had moved to a super centre then it could have been chaos."