Irish medical devices firm Mainstay Medical, which agreed a debt facility of up to $15 million (€13.1 million) earlier this week, has been awarded an additional US patent as it continues with moves to bring a new product to market.

Mainstay said in a statement on Thursday it had been awarded a patent entitled “Apparatus and methods for rehabilitating a muscle and assessing progress of rehabilitation.” Corresponding applications have been made in other countries and Mainstay said it intends to add to its portfolio of issued patents and pending applications.

"Mainstay is growing a strong intellectual property portfolio and this latest US patent, our third issued this year, is part of our continued development of that portfolio," said chief executive Peter Crosby.

The company received approval last year from the Food and Drug Administration (FDA) in the US to begin a clinical trial of its implantable neurostimulation system aimed at treating chronic low back pain.

The system, Reactiv8, helps restore control to the muscles that stabilise the lumbar spine.

On Monday, the company said it had agreed a new debt facility with IPF Partners which would be used to allow it to continue to push forward with commercialisation of Reactiv8.

The initial tranche of $4.5 million is to be made available immediately, with the second and third drawn when the company hits certain milestones for the product.

All three tranches have repayment terms of 60 months, with interest-only payments for the first 12 months.