The global computer system that tracks manufacturing and customer orders for Medtronic PLC is back online, but the medical device maker now has catch-up work to do after running for nearly a week without a critical IT system.

A company spokesman said Medtronic's computers were up and running again on Monday, nearly a full week after the system first went down because of an undisclosed internal technical problem. The problem triggered extra shifts for many company employees.

Although Medtronic spokesman Fernando Vivanco didn't know specifically how many customer orders had been disrupted by the outage, he said the problem affected business operations globally.

"There was some variation of impact across Medtronic's four major businesses based on their underlying systems," Vivanco said in an e-mail Monday. "We continue to work extensively to quickly process and ship orders made during this interruption."

A message to employees from CEO Omar Ishrak last week said that Medtronic had determined the problem started internally at the company and that there was no indication of any "outside agent" being involved, nor any data breach.

On Friday, Vivanco noted that a root-cause analysis was ongoing.

Although the company said Thursday that "our fundamental system has been restored," employees noted that the system appeared to remain down until the weekend. Vivanco said the system was "up and running" by Monday.

Last week, Vivanco said the company would be in a better position to evaluate the financial impact of the outage once the system was restored, but at the time, it didn't appear that it would have a material impact on quarterly financials.