Department of Neurosurgery, Fukuoka Children's Hospital, 5-1-1 Kashii-teriha, Higashi-ku, Fukuoka, 813-0017, Japan.
Department of Neurosurgery, Kitakyushu Municipal Medical Center, Kitakyushu, Japan.
Childs Nerv Syst. 2020 Feb;36(2):423-427. doi: 10.1007/s00381-019-04301-1. Epub 2019 Jul 11.
A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated cord-like structure extending continuously from the conus medullaris to the dural cul-de-sac that is caused by late arrest of secondary neurulation. Five patients with RMC extending to an associated sacral subcutaneous meningocele have been reported.
We report an additional patient with RMC, in whom a congenital dermal sinus (CDS) was found in the caudal portion of the RMC. At the age of 3 days, the patient underwent surgery consisting of meningocele excision and cord untethering, and CDS was noted histologically in the proximal cut end of the RMC. During a second surgery at the age of 5 months, after determining the exact border of the nonfunctional RMC and the true conus by neurophysiological mapping, we removed the entire length of the remnant RMC, including newly developed epidermoid cysts in the CDS.
Although the exact pathoembryogenesis of concurrent RMC and CDS is unknown, an associated subcutaneous meningocele, caused by failure of primary neurulation, could be involved. Surgeons should be aware of the possibility of the coexistence of CDS when dealing with RMCs that extend out to the extradural space.
硬脊膜内残留脊髓（RMC）是一种罕见的闭合性脊髓脊膜畸形，其特征为一条结构完整的延长状脊髓样结构，从脊髓圆锥连续延伸至硬脊膜囊末端，这是由于二次神经管闭合过程晚期停止所致。目前已有 5 例 RMC 延伸至与之相关的骶部皮下脑膜膨出的病例报道。
我们报告了另一名 RMC 患者，其 RMC 的尾部存在先天性皮窦（CDS）。在 3 天大时，患者接受了手术治疗，包括脑膜膨出切除和脊髓松解，在 RMC 的近端切断端发现了 CDS 的组织学特征。在 5 个月大时进行了第二次手术，通过神经生理定位确定了无功能 RMC 和真正的脊髓圆锥的确切边界后，我们切除了整个 RMC 残段，包括 CDS 中新出现的表皮样囊肿。
尽管同时存在 RMC 和 CDS 的确切病理胚胎学机制尚不清楚，但可能与原发性神经管闭合失败有关的伴发皮下脑膜膨出有关。外科医生在处理延伸至硬脊膜外间隙的 RMC 时，应注意 CDS 同时存在的可能性。
