SANTA ROSA -- Osseon Therapeutics, Inc. announced staffing changes that include Ron Clough being promoted to chief executive officer in September, as the medical device maker seeks to bolster its presence  in Europe, which accounts for 40 percent of its total sales.

Mr. Clough was hired in August as the company's chief operating officer. He has extensive experience with several companies that develop and market medical devices for the treatment of spinal disease and deformities. Most recently, he served as VP of operations at Theken Spine and was a key executive in the acquisition and integration of Theken Spine into Integra LifeSciences, an international medical device company. Integra LifeSciences acquired Theken for $200 million dollars in a two-year earn out in July, 2008.

Mr. Clough replaces former Osseon CEO John Stalcup.

Osseon also said its former president, Doug Clark, has rejoined the company as a member of its board of directors.  Mr. Clark has over 25 years of experience in medical device sales, sales management and business development.

And Osseon named Jon Nolan as its new director of sales.  Mr Nolan has worked in sales and surgeon training at Zimmer Spine, Johnson & Johnson, Stryker, and Vertebron. Mr. Nolan also served as a U.S. Army Ranger Captain. Mr. Nolan will be focusing his attention on acquiring distribution opportunities in the U.S.

Santa Rosa-based Osseon is hoping to develop and commercialize medical devices for minimally invasive treatments for degenerative bone and joint disease, including the treatment of vertebral compression fractures. It's newest product,  Osseoflex SB, is a vertebral augmentation device. The Osseoflex SB steerable bone tamp, introduced to the European marketplace in second quarter of 2012, has driven the company's revenue and distribution has expanded to six EU countries, with further growth expected.