CHICAGO (Reuters) - Medical device maker Medtronic Inc (MDT.N: Quote, Profile, Research) announced a series of management changes on Tuesday and said chief operating officer Michael DeMane was leaving the company to pursue other opportunities.

Medtronic's global business unit presidents will report to President and Chief Executive Bill Hawkins, effective immediately, the company said. Hawkins assumed the CEO position in August, replacing Art Collins, who held the post from 2001 to 2007.

The Minneapolis-based company also appointed Jean-Luc Butel as senior vice president and president of Medtronic International, James Dallas as senior vice president for quality and operations, and Katie Szyman as senior vice president of a newly formed strategy and development group.

Steve LaNeve, formerly president of Medtronic Japan, was named senior vice president and president of Medtronic's spinal and biologics business, replacing Pete Wehrly, who is leaving the company.

JP Morgan analyst Michael Weinstein said Hawkins is starting to put his stamp on the company. Eliminating the COO role puts "more responsibility and control in Hawkins' hands," Weinstein said in a note.

Medtronic's spine business, historically a key growth driver, needs to deliver better results for the company to hit its growth goals, Weinstein said, and Wehrly's departure raises concerns because Medtronic is in the midst of integrating its Kyphon acquisition.

Morgan Stanley analyst Glenn Reicin called DeMane's departure a "blow to the company's senior management structure" but an expected development.

"We thought the chief operating officer role was not enough to keep DeMane around," Reicin said in a note to clients.

"We are not surprised to see changes in the spinal division, as our diligence suggests this segment is struggling, especially the Kyphon integration," Reicin wrote.