For many years it has been known that the transverse fibers of the palmar fascia participate in flexor tendon biomechanics. Therefore, their thickening can contribute to triggering in certain individuals' digits. Many people, including diabetics, have a "Dupuytren's diathesis": a tendency to thicken their palmar fascia at sites of trauma and injury.
Useful in trigger finger releases, and less so in trigger thumb surgery, is the removal of the longitudinal and transverse bands of palmar fascia at and near the surgical site. This tends to reduce thickening of the scars and thickening of the palmar fascia around the incision. It lessens the possibility of "recurrence" of the triggering due to thickening of the transverse bands of the palmar fascia, grinding against the tendonosis of the flexor tendons. Of course, this is not necessarily a permanent solution, as this fascia has a tendency to regrow.