Related conditions would be, Syringomyelia (syrinx), Ehlers-Danlos Syndrome, POTS, ICP, CCI,tethered cord, bulging disks, scoliosis,retroflexed odontoid,Basilar ingvagnation, sleep apnea,.....as well as the non related conditions lymes, lupus and MS should be ruled out.
Hi and welcome to the Chiari forum.
Surgery does not remove Chiari...just helps lessen symptoms and slows progression, so it is possible to require a second surgery.
May I ask, outside of syringomyelia and Chiari do you have any other related conditions?