A device for dividing a fibrous structure comprising a catheter; an expandable member positioned near a distal end of the catheter and in fluid communication with a lumen of the catheter; and a cutting element situated on an outer surface of the expandable member. A method for dividing a fibrous structure comprising positioning, proximate the fibrous structure, an expandable member having a cutting element situated thereon; expanding the expandable member outwards to tension the fibrous structure across the cutting element; and activating the cutting element to weaken or cut the fibrous structure. A method for treating carpal tunnel syndrome comprising inserting a needle into the carpal tunnel; directing a guidewire to a position proximate the transverse carpal ligament; advancing, along the guidewire, a device having an expandable member and a cutting element; positioning the cutting element; tensioning the ligament across the cutting element; and weakening or cutting the ligament.