It’s mixed news for Stryker (NYSE:SYK) today as the FDA limited use of the medical device company’s Wingspan brain stent system to a narrower group of patients over concerns that the devices may do more harm than good.

The FDA revised the device’s approval for patients with recurrent stroke that isn’t well managed through drugs alone and who have not had any new stroke symptoms within a week prior to implantation of the Wingspan stent, according to the FDA notice.

That means the Wingspan devices, which were approved in 2005 under a Humanitarian Device Exemption, won’t undergo a recall as called for by consumer watchdog groups and the former medical device director for the FDA.

"Data collected in clinical studies conducted since HDE approval for Wingspan, including the SAMMPRIS trial, show that Wingspan may present unacceptable risks, such as stroke and death, to many patients previously considered appropriate for treatment with Wingspan," according to the FDA notice. "While Wingspan is not beneficial for the broad population of stroke patients studied in SAMMPRIS, there is evidence from the original HDE study to show there are probable benefits of using Wingspan to treat the specific population of patients outlined in the new indications for use."

Stryker representatives did not immediately return requests for comment.

Consumer watchdog group Public Citizen had asked the federal government to recall Wingspan entirely over concerns that it may lead to heightened risk of stroke and death. Former FDA medical device director Larry Kessler joined the petition, asking that the agency pull the stents off the market "because, when combined with aggressive medical treatment, they provide no additional benefit but cause significantly more harm than safer aggressive medical treatment alone," according to the group’s petition.

Stryker got a chance in March to defend Wingspan during a meeting with the FDA’s neurological devices panel. The panel considered pre-market and post-market data on the device, including the Gateway PTA balloon catheter and stent delivery system.

Stryker is currently the only company with the FDA’s OK to sell a brain stent for certain high-risk patients in the U.S. who haven’t responded to drug treatment, having acquired it as part of a $1.5 billion cash buyout of Boston Scientific’s (NYSE:BSX) neurovascular business in October 2010. Thousands of patients have received the stent so far.

The trouble began when researchers concluded that high-risk patients who only took medication and received lifestyle coaching had better outcomes than those who also received the implant.

In September 2011, researchers released study results finding that stroke and death rates among patients who received the Wingspan system were 20% at 1 year, compared to 12.2% for the non-stented patients. The results came from the Stenting & Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) study.

Researchers suggested that the stent implantation procedure may have dislodged some arterial plaque from the original brain site and set it loose to block other, narrower arteries. Trial enrollment was cut off early when a high adverse effect proportion was found. The study was designed for up to 764 patients, but recruitment was halted when the Data Safety Monitoring Board determined there was enough evidence for a conclusive finding after 451 patients signed on.

"The SAMMPRIS trial did not follow the current HDE indication for use; it focused on studying the treatment of severe intracranial atherosclerotic disease, early in the treatment lifecycle and with an aggressive drug treatment regimen and rigorous oversight of medication compliance," Stryker spokeswoman Tamara Cutler told MassDevice.com in February, adding that the system is cleared for use in no more than 4,000 patients per year.

"Stryker continues to support the Wingspan stent system and Gateway PTA balloon catheter as an FDA approved Humanitarian Use Device for improving cerebral artery lumen diameter in patients with intracranial atherosclerotic disease who have failed medical therapy," the company said in a statement sent to MassDevice.com late last year.

Wingspan’s new labeling, approved today, specifies use of the device in patients aged 22-80 who have experienced at least 2 strokes despite "aggressive medical management." The devices should not be used for treatment of stoke within a week of Wingspan implantation or for treatment of transient ischemic attack, according to the new labeling.

Wall Street seemed to take little notice and SYK shares remained flat on the day, trading at $52.99 as of about 4:45 p.m.