The "presyrinx" state: A reversible myelopathic condition that may precedesyringomyelia

BACKGROUND AND PURPOSE: Alteration of CSF how has been proposed to be an im portant mechanism leading to the development of syringomyelia. We hypothesi ze that a "presyrinx" condition attributable to a potentially reversible al teration in normal CSF flow exists and that its appearance may be caused by variations in the competence of the central canal of the spinal cord, METHODS: Five patients with clinical evidence of myelopathy, no history of spinal cord trauma, enlargement of the cervical spinal cord with T1 and T2 prolongation but no cavitation, evidence of altered or obstructed CSF how, and no evidence of intramedullary tumor or a spinal vascular event underwen t MR imaging before and after intervention that alleviated obstruction to C SF flow, RESULTS: Preoperatively, all patients had enlarged spinal cords and parench ymal T1 and T2 prolongation without cavitation, Results of MR examinations after intervention showed resolution of cord enlargement and normalization or improvement of cord signal abnormalities. In one patient with severe ara chnoid adhesions who initially improved after decompression, late evolution into syringomyelia occurred in association with continued CSF obstruction. CONCLUSION: Nontraumatic obstruction of the CSF pathways in the spine may r esult in spinal cord parenchymal T2 prolongation that is reversible after r estoration of patency of CSF pathways. We refer to this MR appearance as th e "presyrinx" state and stress the importance of timely intervention to lim it progression to syringomyelia.