A specialist neurosurgery unit should be centralised in Cardiff rather than in Swansea, say health officials.
Adult brain surgery services should be centred in Cardiff, review finds
Health Commission Wales (HCW) has chosen the University Hospital of Wales after a review. The plan now goes out to public consultation.
Swansea's Morriston Hospital, which also has a brain surgery unit, was the other option and trust managers called the recommendation "seriously flawed".
Project leaders said it was "based solely on improving patient care".
Swansea previously lost its child neurosurgery operations to Cardiff in November 2004.
Currently, adult neurosurgery is performed in both Cardiff and Swansea. Neurosurgery treats disorders of the nervous system including diseases of the head, brain and spine.
But a strategic review presented to HCW's national commissioning advisory board in December decided keeping both surgical units going would be unsustainable.
A review of neurosurgery services in by HCW found operations should be centralised at one hospital.
Over the past eight weeks, a consultation exercise has been held to decide which of the two hospitals will no longer perform adult neurosurgery.
A board meeting on Friday decided the amalgamated south Wales neurosciences centre should go to Cardiff.
The recommendation - which was opposed by the representative from Swansea NHS Trust on the board - means brain surgery for children and adults would no longer be available at Morriston.
David Hardy, consultant neurosurgeon who was chair of the project board said the decision was based "solely on improving patient care".
He said: "Creating a single service in Cardiff will help to safeguard the future of this service in south Wales, and will allow us to develop a wider range of neurosurgical services for the people of mid, west and south Wales.
"Outpatient services will remain in Swansea so most people will only have to come to Cardiff for inpatient care, which is a small part of their treatment."
But Swansea NHS Trust said the recommendations were "seriously flawed" and "based on a number of erroneous conclusions".
A spokesman added: "Senior managers within the trust will be working closely with clinicians over the coming weeks to develop a comprehensive response to the proposals and setting out why this important service should remain in Swansea."
South Wales West AM Dai Lloyd said it would affect patients living in mid and west Wales, who would face longer journeys for treatment.
Dr Lloyd said: "It is a savage blow to patient access particularly because the ambulance service is having difficulty in reaching response time targets to emergencies."
Neath AM Gwenda Thomas said she was "deeply disappointed and angry" but that the fight would continue.