TRANSDURAL SPINAL-CORD HERNIATION - IMAGING AND CLINICAL SPECTRA

PURPOSE: Transdural herniation of the spinal cord is a rarely reported clinical entity, and many of the existing reports were published befo re the advent of MR imaging. We describe five current cases and compar e them with findings in 25 cases reported in the literature to delinea te the clinical and imaging spectra of transdural spinal cord herniati on. METHODS: MR imaging, CT myelography, and conventional myelography were performed in five patients with transdural herniation of the spin al cord. These studies, along with clinical findings, are described. I ntraoperative photographs are included for one case. The salient featu res of both the current and previously reported cases are summarized i n tabular form. RESULTS: In three cases, transdural spinal cord hernia tion occurred posttraumatically, in one case the cause was iatrogenic and in the others the herniation occurred spontaneously. Imaging featu res not previously reported include dorsally directed herniations at t horacolumbar levels (two patients), apparent (lacking surgical confirm ation) syringomeyelia (one case), a vertebral body nuclear trail sign (one case), and intramedullary hyperintensities on MR images (two case s). Clinical features not previously reported include unilateral pyram idal-sensory deficits (one case) and isolated unilateral pyramidal sig ns (one case). Clinical findings similar to previous reports include p rogressive paraparesis (two cases) and progressive Brown-Sequard syndr ome (one case). CONCLUSION: Our five cases illustrate certain clinical and imaging findings not previously reported, and, together with the established features of the 25 cases in the literature, delineate the spectra of transdural spinal cord herniation.