(Reuters) - The U.S. Food and Drug Administration approved Medtronic Inc's device to permanently treat varicose veins on the legs.

The VenaSeal closure system works by sealing the affected veins using an adhesive agent injected through a catheter.

Varicose veins are swollen veins that are usually blue or dark purple. They often cause muscle cramps and an uncomfortable, heavy feeling in the affected area.

Veins contain tiny valves that stop blood from flowing backwards. Damage to these valves can cause blood to swell in the veins.

Since the device does not use heat application or cutting, the in-clinic procedure allows patients to quickly return to normal activities. (http://1.usa.gov/1Asb0bb)

The device is manufactured by Covidien LLC, whose acquisition Medtronic completed last month.

(Reporting by Amrutha Penumudi in Bengaluru; Editing by Maju Samuel)