Syringomyelia intermittens: highlighting the complex pathophysiology of syringomyelia. Illustrative case

Abstract

BACKGROUND Chiari Type I malformation (CM1) is a disorder recognized by caudal displacement of the cerebellar tonsils through the foramen magnum and into the cervical canal. Syringomyelia is frequently found in patients with CM1, but the pathophysiology of syringomyelia remains an enigma. As a general consensus, symptomatic patients should be treated and asymptomatic patients without a syrinx should not be treated. Mildly symptomatic patients or asymptomatic patients with a syrinx, on the other hand, pose a more challenging dilemma, as the natural evolution is uncertain. For many surgeons, the presence of a syrinx is an indication to offer surgery even if the patient is asymptomatic or mildly symptomatic. OBSERVATIONS The authors describe an illustrative case of a 31-year-old female with an incidental finding of a CM1 malformation and cervical syrinx in 2013. Conservative management was advocated as the patient was asymptomatic. Monitoring of the syrinx over a course of 8 years showed resolution, followed by reappearance and finally a complete resolution in 2021. A review of the literature and the possible pathophysiology is discussed. LESSONS The unusual course of this patient highlights the importance of guiding treatment by clinical symptoms, not radiological findings. Furthermore it reflects the complexity of the pathophysiology and the uncertain natural history of syringomyelia.

Successful treatment of unilateral facial nerve palsy in a pediatric patient with syringobulbia and Chiari malformation type I: illustrative case

“…Additionally, the SSS catheters can obstruct and fail due to an inflammatory response and adhesion. 16 Although the literature features one patient who presented with syringomyelia, syringobulbia, and left gaze paralysis, 14 our case is unique given the presentation of both syringomyelia and syringobulbia in conjunction with unilateral CN VII deficit. As previously stated, CN VII palsy is rarely observed (5%) 6 in patients with syringobulbia because of the location of the CN VII nucleus in the brainstem.…”

“…This explanation proposed that a syrinx could be caused by the flow of CSF from the fourth ventricle being blocked, which would push the CSF through a patent central canal. 14 The second theory, proposed in 1969, stated that a block in caudal CSF flow causes increased intracranial pressure, forcing CSF from the fourth ventricle into the central canal. 14 Additionally, the third theory, termed the piston theory, presented the idea that a syrinx was caused by the cerebellar tonsils creating large pressure waves in the spinal subarachnoid space, forcing fluid through the surface of the spinal cord into the central canal.…”

“… 14 The second theory, proposed in 1969, stated that a block in caudal CSF flow causes increased intracranial pressure, forcing CSF from the fourth ventricle into the central canal. 14 Additionally, the third theory, termed the piston theory, presented the idea that a syrinx was caused by the cerebellar tonsils creating large pressure waves in the spinal subarachnoid space, forcing fluid through the surface of the spinal cord into the central canal. 14 Although many hypotheses have been produced, there is still no definitive answer regarding any single cause of syringomyelia and syringobulbia; each presentation is likely the result of one or more of the above pathophysiological processes.…”

Spontaneous improvement in syringomyelia in a patient with Chiari 1 malformation: illustrative case

“…It was described by Arnold Chiari in 1891. 1 The prevalence of CM1 in the population is between 0.24% and 0.9%. 2 Radiographically, it is defined as the displacement of the cerebellar tonsils of 5 mm or more below the McRae line.…”