Nobuya Murakami1, Takato Morioka2,3, Takafumi Shimogawa3,4, Kimiaki Hashiguchi4, Nobutaka Mukae4, Kazuyoshi Uchihashi5, Satoshi O Suzuki6, Koji Iihara4. 1. Department of Neurosurgery, Fukuoka Children's Hospital, 5-1-1 Kashii-teriha, Higashi-ku, Fukuoka, 813-0017, Japan. murakami.n@fcho.jp. 2. Department of Neurosurgery, Fukuoka Children's Hospital, 5-1-1 Kashii-teriha, Higashi-ku, Fukuoka, 813-0017, Japan. 3. Department of Neurosurgery, Kyushu Rosai Hospital, Kitakyushu, Japan. 4. Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. 5. Department of Surgical Pathology, Kyushu Rosai Hospital, Kitakyushu, Japan. 6. Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Abstract
BACKGROUND: A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac. One case extending down to the base of a subcutaneous meningocele at the sacral level has been reported. CLINICAL PRESENTATION: We report on three cases of closed spinal dysraphism, in which a spinal cord-like tethering structure extended out from the dural cul-de-sac and terminated at a skin-covered meningocele sac in the sacrococcygeal region, which was well delineated in curvilinear coronal reconstructed images of 3D-heavily T2-weighted images (3D-hT2WI). Intraoperative neurophysiology revealed the spinal cord-like tethering structure was nonfunctional, and histopathology showed that it consisted of central nervous system tissue, consistent with RMC. The tethering structure histologically contained a glioneuronal core with an ependymal-like lumen and smooth muscle, which may indicate developmental failure during secondary neurulation. CONCLUSIONS: When the RMC extending to a meningocele is demonstrated with the detailed magnet resonance imaging including 3D-hT2WI, decision to cut the cord-like structure for untethering of the nervous tissue should be made under careful intraoperative neurophysiological monitoring.
BACKGROUND: A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac. One case extending down to the base of a subcutaneous meningocele at the sacral level has been reported. CLINICAL PRESENTATION: We report on three cases of closed spinal dysraphism, in which a spinal cord-like tethering structure extended out from the dural cul-de-sac and terminated at a skin-covered meningocele sac in the sacrococcygeal region, which was well delineated in curvilinear coronal reconstructed images of 3D-heavily T2-weighted images (3D-hT2WI). Intraoperative neurophysiology revealed the spinal cord-like tethering structure was nonfunctional, and histopathology showed that it consisted of central nervous system tissue, consistent with RMC. The tethering structure histologically contained a glioneuronal core with an ependymal-like lumen and smooth muscle, which may indicate developmental failure during secondary neurulation. CONCLUSIONS: When the RMC extending to a meningocele is demonstrated with the detailed magnet resonance imaging including 3D-hT2WI, decision to cut the cord-like structure for untethering of the nervous tissue should be made under careful intraoperative neurophysiological monitoring.