Almost half of patients who were given a controversial type of bowel surgery should not have been operated on, a hospital trust has admitted.
North Bristol NHS Trust has told 57 patients at Southmead Hospital in Bristol they should have been offered alternative treatment first.
Surgeon Tony Dixon was suspended in 2017 after concerns were first raised.
Dozens of women had told the BBC they were left in severe pain after pelvic floor surgery using artificial mesh.
Mr Dixon pioneered the use of artificial mesh to lift prolapsed bowels – a technique known as laparoscopic ventral mesh rectopexy (LVMR) – often caused by childbirth.
The trust carried out a review after concerns were raised with the BBC by patients who suffered complications and ended up in chronic pain following the procedure.
Paula Goss, 49, from south Gloucestershire, was told the surgery “would change her life [and] would make everything better” but was now “disabled in many ways because of it”.
The operations began in the early 2000s, although the review only investigated cases from 2007 to 2017.
The vast majority of the operations were carried out by Mr Dixon, but some were performed by a further three surgeons.
The trust said although their operations were carried out successfully, the 57 patients were told they “should have been offered alternative treatments before proceeding to surgery”.
A further 73 patients have been told their surgery was appropriate, and investigations into 13 other cases are still to be completed.
The trust’s medical director, Dr Chris Burton, said he wanted to apologise to patients who received unnecessary surgery.
“It is unacceptable and we are taking it extremely seriously,” he said.
He added immediate action was taken to “ensure it couldn’t happen again”, and patients have been supported.
“We will keep investigating to ensure we have identified those patients affected by these issues, and to find out what happened to learn lessons for future care.”
Mr Dixon, who also performed operations at Spire Hospital in Bristol, said he was “unable to comment on specific allegations… due to patient confidentiality and while relevant investigations are on-going”.
“There is a need for caution in comparing the use of mesh in different procedures with very different risks and outcomes,” he added.
Spire Healthcare said it was carrying out a similar review which it hoped would be complete in May.