We have a Tarlov cyst sub forum, or use the search tool to find post mentioning Tarlov in all our forums..
https://www.neurotalk.org/search.php
I would ask.. is the leg really shorter? , or are hips actually uneven making the leg seem shorter on one side.. Did any drs actually measure & compare hips, knees, shoulders for level or not?
If no obvious surgical need shows in MRI and other imaging.. might consider expert chiropractic , PT or body worker for whole alignment assessment.. and they may be able to help get discs back into place.