Is it possible for a traumatic syrinx to grow larger? i don't have chiari malformation.

Yes: Syrinx can enlarge / elongate. Sometimes tiny shunts are placed if the Neurosurgeon believes this will prevent elongation (if there is production of fluid under pressure within the syrinx ). We monitor the stability of the syrinx with serial neurological exams over time. The majority of the time the situation remains stable and new symptoms arise for other reasons. (Neuropathy, Carpal Tunnel etc)