Medical device maker Medtronic is advising doctors and patients to pay close attention to all malfunction alarms on implantable SynchroMed II drug pumps because of a problem that has caused a handful of newer pumps to seize up and stop delivering medication for chronic pain and spasticity.

The Food and Drug Administration said Monday that Medtronic is recalling about 11,000 SynchroMed II pumps made between May 2018 and April 2019 because of a manufacturing problem that caused certain pumps to retain a "foreign particle" that can permanently jam the device motor.

The problem is considered rare but serious, because a permanent motor stall will cause the device to stop pumping liquid medication into the intrathecal space around the spine, causing the re-onset of symptoms and potentially triggering withdrawal. For patients receiving the anti-spasticity drug baclofen, a motor stall could lead to a condition called baclofen withdrawal syndrome.

"Permanent motor stall could … cause serious injury, such as drug withdrawal, the return of symptoms of underlying conditions, the need for surgery to replace the pump, or death," the FDA said in a MedWatch alert that was e-mailed Monday.

Medtronic said the manufacturing issue has since been fixed. The problem was not seen in devices made before the recall dates. Medtronic's neuromodulation office on Central Avenue in Fridley is handling the voluntary recall, which was first announced by the company in October and re-emphasized on Monday.

The recall applies to devices made between May 4, 2018, and April 5, 2019, with model numbers 8637-20 or 8637-40. Not every device with those numbers made between those dates is affected; rather, customers can enter the device's serial numbers into Medtronic's online recall portal to find out if their pump is affected. The company also has provided implanting physicians with a list of their patients who may be affected.

Although Medtronic recommends doctors return unused devices to the company, it is not recommending that implanted devices affected by the recall be removed. That's because the risk of complications from replacement surgery (2.1%) far outweigh the risks of a pump motor stall from any cause (0.2%), the company said.

So far Medtronic has confirmed five cases of early permanent motor stall in affected SynchroMed II pumps because of the foreign particle, including two cases identified before implantation. The three other motor stalls happened within five months of implant. No deaths are linked to the problem.

In all cases, the pump's critical alarm functioned properly, Medtronic said. A jammed pump will trigger an audible critical alarm, which also will appear on the device a doctor uses to communicate with the pump in-office and the A820 myPTM application for patients with an at-home device programmer.

The company recommends that patients, caregivers and physicians affected by the recalled device communicate about what to look for if the motor stalls.

"Medtronic is not recommending prophylactic replacement of potentially affected SynchroMed II pumps, due to the low observed occurrence of motor stall from this issue, the presence of pump alarms, and the risks associated with replacement surgery," Medtronic's letter to customers Monday said.