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Surgical mesh deemed unsafe for one medical problem is being used for another

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Surgical mesh can no longer be used to treat New Zealand women with pelvic organ prolapse (POP) after Medsafe removed four POP mesh products from the market in January.

That decision, which effectively bans the use of vaginal mesh to treat POP, was made due to safety concerns. The mesh has been associated with serious, long-term complications such as chronic pain, infection, vaginal bleeding and bowel problems.

However, the ban does not apply to vaginal mesh used to treat stress urinary incontinence (SUI) – involuntary urination caused by physical movement or activity such as coughing, sneezing, running or heavy lifting.

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This year, up to 1400 Kiwi women with SUI will have what’s known as a mid-urethral sling made of polypropylene mesh implanted through their vagina to support their urethra or bladder neck.

But the growing international controversy about the use of vaginal mesh to treat both POP and SUI – it’s been described as “the new thalidomide” because of its sometimes-devastating consequences – means they face a difficult decision: to have surgery or not?

“Every patient who comes to see me brings it up, and I have to go through the evidence with them,” says Dr Lynsey Hayward, a urogynaecologist at Middlemore Hospital.

Dr Lynsey Hayward.

As far as she’s concerned, the evidence for mid-urethral slings is convincing. She supports Medsafe’s decision to stop the use of vaginal mesh to treat POP, saying there are much more effective, non-mesh surgical options available. However, she describes mid-urethral slings as a “very different animal” and has no qualms about using them for patients who have not responded to non-surgical treatments for SUI. These include pelvic floor physiotherapy, weight loss and continence pessaries.

“I would use mid-urethral slings as a first-line surgical treatment for my patients and so would my colleagues.”

Hayward recommends using retropubic slings, which are inserted through an incision in the front wall of the vagina, rather than trans-obturator slings, which are inserted through two small cuts at the top of each thigh. She says retropubic slings have fewer complications and are also easier to remove.

“If I had stress urinary incontinence I would absolutely have a retropubic mid-urethral sling.”

Hayward also supports the Ministry of Health’s decision to develop a credentialling system for surgeons inserting the slings; she represents the Royal Australian and New Zealand College of Obstetricians and Gynaecologists on the credentialling committee. In the meantime, the ministry has told district health boards to stop offering the surgery if their surgeons don’t meet Australian credentialling guidelines. These include a requirement to perform at least 10 procedures a year, which is likely to limit the availability of the surgery at smaller regional hospitals.

“It’s clear from studies that high-volume surgeons who are experienced and used to doing the surgery have a much lower complication rate than those who are only doing it occasionally,” says Hayward. “That would apply to any surgery – any surgery at all.”

Carmel Berry.

Mesh Down Under, a support and advocacy group for people injured by mesh, also supports the credentialling process, though – not surprisingly – it takes a more cautious approach to the use of mid-urethral slings to treat SUI. Co-founder Carmel Berry is less convinced by the data than Hayward and says there is not yet much information about the long-term effects of the slings.

“Some people are fine for three or four years, then all kinds of problems start to arise.”

She doesn’t necessarily believe the slings should be banned, but does think they should be used only as a last resort – and only when women are aware of all the possible complications. “The proviso is that the patient must be fully consented.”

She’s helping to write a Ministry of Health information document about the different options for SUI treatment and their possible complications, which will have to be signed by both the patient and the surgeon before surgery goes ahead.

Berry says women who do opt to have a mid-urethral sling inserted should also have a plan in place so that any post-operative problems are fixed as quickly as possible.

“Something I’ve learnt recently is that if you’re in pain at six weeks post-operatively, you’re probably always going to be in pain unless you get it taken out.”

This article was first published in the December 1, 2018 issue of the New Zealand Listener.