Morioka Takato, Murakami Nobuya, Yanagida Haruhisa, Yamaguchi Toru, Noguchi Yushi, Takahata Yasushi, Tsukamoto Ayumi, Suzuki Satoshi O
Department of Neurosurgery, Fukuoka Children's Hospital, 5-1-1 Kashii-teriha, Higashi-ku, Fukuoka, 813-0017, Japan.
Department of Orthopedics and Spine Surgery, Fukuoka Children's Hospital, Fukuoka, Japan.
Childs Nerv Syst. 2020 Apr;36(4):819-826. doi: 10.1007/s00381-019-04297-8. Epub 2019 Jul 17.
Limited dorsal myeloschisis (LDM) is characterized by a fibroneural tethering stalk linking the skin lesion to the underlying spinal cord. Terminal syringomyelia, which is located at the lower third of the cord, is often associated with a tethered cord caused by various spinal dysraphisms; however, terminal syringomyelia has not been documented in LDM. The purpose of this study was to clarify the pathophysiological mechanisms of syringomyelia in LDM.
In our 16 patients with lumbar LDM, three patients had terminal syringomyelia. We retrospectively analyzed the clinical, neuroradiological, intraoperative, and histopathological findings for these patients, with particular attention to the clinical course of the syrinx.
Patient 1 had a saccular skin lesion and patients 2 and 3 had flat lesions. In all patients, the syringomyelic cavity was located in the lower thoracolumbar cord, immediately rostral to the stalk-cord attachment at the lumbar level. The caudal pole of the syrinx extended to the thickened stalk at the attachment instead of at the caudal cord. Patient 3 had another syrinx in the stalk itself. The longitudinal axis of the syrinx and central canal coincided with the traveling angle of the LDM stalk at the stalk-cord attachment. In patient 1, histology revealed an ependyma-lined central canal in both the LDM stalk and meningocele sac. Patients 1 and 2 underwent syringostomy, but long-term effects were not obtained. Preoperative spontaneous resolution occurred in patient 3.
The histological findings in patient 1 supported the idea that segmental myelocystocele is involved in the development of saccular LDM. The hydromyelic central canal herniates and distends the stalk, resulting in the formation of the myelocystocele. It is possible that the hydromyelic central canal also distends the stalk of flat LDM lesions. The syrinx in patient 3 differed from that in patients 1 and 2, in that the syrinx resolved spontaneously. Further studies are needed to clarify the outcomes of syrinxes associated with LDM stalks.
局限性背侧脊髓纵裂（LDM）的特征是存在一条纤维神经束带，将皮肤病变与下方的脊髓相连。终末型脊髓空洞症位于脊髓下三分之一处，常与各种脊柱裂导致的脊髓栓系相关；然而，LDM中尚未有终末型脊髓空洞症的相关报道。本研究的目的是阐明LDM中脊髓空洞症的病理生理机制。
在我们的16例腰椎LDM患者中，有3例患有终末型脊髓空洞症。我们回顾性分析了这些患者的临床、神经放射学、术中及组织病理学表现，尤其关注脊髓空洞症的临床病程。
患者1有一个囊状皮肤病变，患者2和3有扁平病变。在所有患者中，脊髓空洞腔位于胸腰段脊髓下部，紧邻腰椎水平束带与脊髓附着处的头侧。脊髓空洞的尾极延伸至附着处增厚的束带而非尾侧脊髓。患者3在束带本身还有另一个脊髓空洞。脊髓空洞和中央管的纵轴与LDM束带在束带 - 脊髓附着处的走行角度一致。在患者1中，组织学检查显示LDM束带和脊膜膨出囊内均有室管膜衬里的中央管。患者1和2接受了脊髓空洞造瘘术，但未获得长期效果。患者3术前脊髓空洞自发消退。
患者1的组织学发现支持节段性脊髓囊肿膨出参与囊状LDM形成的观点。积水性中央管疝出并扩张束带，导致脊髓囊肿膨出的形成。积水性中央管也可能扩张扁平LDM病变的束带。患者3的脊髓空洞与患者1和2不同，其脊髓空洞自发消退。需要进一步研究以阐明与LDM束带相关的脊髓空洞症的转归。
