Limited dorsal myeloschisis: a single-center retrospective study of a rare spinal dysraphism

Background: Limited dorsal myeloschisis (LDM) is a rare form of spinal dysraphism, reported in the literature to account for 1–8% of all cases of spinal dysraphism. The purpose of this paper is to report a single-center series of LDM and to discuss its clinical features, surgical management, and outcomes. Methods: We conducted a retrospective analysis of 360 cases of spinal dysraphism from January 2019 to May 2024. Eighteen cases with LDM were included in the study. The inclusion criteria were open and closed spinal dysraphism admitted to our hospital. Results: The most common location was D5-D8 (61% of cases). All mothers who had hyperemesis gravidarum ( n = 9, 50%) delivered a baby with a neural tube defect (NTD). Thirteen mothers (72%) underwent an NT scan; of these, 11 (61%) had no prenatal diagnosis of an NTD. Tethering was identified at the level of the corresponding spinal lesion in 16 patients (89%); in the remaining 2, tethering occurred at a sublesional level, necessitating a separate incision for filum terminale detethering. Twenty-two percent had skin tags, and 11% had hair and dermal sinus as neurocutaneous markers. All patients underwent microsurgical sac excision. Conclusion: LDM is structurally and clinically distinct from lumbosacral MMC and generally has more favorable outcomes after surgery. Surgical treatment should be performed early. Intradural exploration is recommended in addition to the resection of the sac. Folic acid supplementation should begin at least three months before conception and be continued for at least 100 days to reduce the risk of NTDs.