Posttraumatic syrinx resulting in syringomyelia and syringobulbia: illustrative case

BACKGROUND Posttraumatic syringomyelia (PTS) refers to an elongated, intramedullary spinal cyst, representing a spectrum of severity and a variable interval after spinal cord injury (SCI). It typically presents with worsening motor and/or sensory function after a period of relative symptom stability following injury. The worsening ascends rostrally to include spinal cord levels previously intact above the level of injury. Rarely, PTS cavities extend rostrally to brainstem levels. OBSERVATIONS The case presented demonstrates nearly the full spectrum of features associated with PTS. The onset of worsening occurred relatively early, about 1 year after motor complete SCI at the T2–3 level. The delayed onset of worsening symptoms of the PTS included asymmetric sensory and motor deficits that extended rostral to the upper extremities, face, and swallowing, and caudal to include back pain. LESSONS The authors highlight key features of PTS, including 1) bilateral ascending expansile syrinx in the peridorsal horn gray matter, 2) medullary extension with trigeminal nucleus symptoms consistent with syringobulbia, and 3) evidence of spontaneous remission or collapsing cord sign. Additionally, risk factors for early PTS are discussed, including motor complete thoracic SCI with spinal stenosis on MRI. Operative management included hardware removal, laminectomy, spinal cord untethering with wide syringostomy, and duraplasty. https://thejns.org/doi/10.3171/CASE25797