If these valves are weak or harmed, blood can flow backward and pool while in the veins, triggering the veins to stretch or twist. As per this journal write-up "Chronic venous insufficiency (CVI) from the lower legs may possibly trigger tissue problems, but involvement of peripheral nerves is unsure." Varicose https://www.sgvascularctr.com/what-surgery-is-available-for-varicose-veins/