Coexisting Chiari malformation (CM) and thoracic outlet syndrome (TOS) in patients presenting with migraine: MRI/MRA/MRV

Abstract

In Chiari malformation the cerebellar tonsils are displaced below the foramen magnum impressing the medulla, with altered cerebrospinal fluid (CSF) flow. Clinically CM mimics other neurologic disorders including migraine and headache disorders; increased intracranial pressure; lower cranial nerve palsies, and spinal cord syndromes, this last in syringomyelia. Thoracic outlet syndrome is misdiagnosed as CM when low‐lying cerebellar tonsils are incidentally found on MRI. Patients undergo decompression surgery without resolution of TOS symptoms because of post‐surgical immobilization; increased sling/erector muscle laxity; round shoulders, and costoclavicular compression. Bilateral MRI/MRA/MRV displays sites of costoclavicular compression of bicuspid valves within lymphatics and draining veins of the neck and supraclavicular fossae and of subclavian and axillary arteries with binding nerve roots (JNMA 1999; 91:333–41). Monitored multiplanar images with abduction external rotation and 2D Time of Flight MRA/MRV without contrast were acquired on a 1.5 Tesla GE Signa LX unit, 44 cm field of view, 512 × 256 matrix and saline water bags to enhance signal to noise ratio. Two patients with both diagnoses are presented whose TOS symptoms worsened after CM decompression, one with syringomyelia, the other a teenage baseball player. Bilateral MRI/MRA/MRV confirmed both diagnoses.