Cervical saccular limited dorsal myeloschisis (LDM), previously so-called "cervical myelomeningocele," is a rare spinal dysraphism. Although the pathogenesis of true myelomeningocele is primary neurulation failure, LDM results from a delayed abnormality during the final stages of neurulation. The aim of the study was to evaluate the outcome of these patients and to assess the correlation of outcomes with the level and type of lesion. Also, pooled data from the literature on similar lesions were systematically reviewed. A retrospective study was conducted at Children's Medical Center (CMC), Tehran, Iran. Information of patients who underwent surgery between 2004 and 2020 (i.e., the recent series) was extracted and combined with data from a previously published series from the same center that were obtained between 2000 and 2003 (CMC series). The literature was reviewed for all published cases, to be combined with the CMC series for further analyses. Twenty-two patients were included in the recent series. Combined with 16 previously published cases, 38 patients with a mean ± SD age at surgery of 11.75 ± 28.64 months were included in the CMC series. The rates of neurological deficit, hydrocephalus, and Chiari malformation type II in the CMC series were 26.32%, 39.47%, and 28.95%, respectively. The lesions were at the upper levels in 17 (44.7%) and lower cervical levels in 21 (55.3%) patients, with 31 cases (81.58%) diagnosed with stalk-type lesions and 7 cases (18.42%) with myelocystocele-type lesions. At final follow-up, 31 patients (81.57%) achieved sphincter continence, and all 36 accessible patients were ambulated, consisting of 28 (73.68%) independent and 8 (21.05%) dependent ambulation patients. The rates of Chiari malformation type II and hydrocephalus were insignificantly higher in patients with upper-level lesions, but those of neurological deficit, ambulation, and sphincter continence were not associated with level. The rates of hydrocephalus (p < 0.01), Chiari type II malformation (p < 0.01), and neurological deficit (p = 0.04) were significantly higher in the myelocystocele group. In the systematic review, 24.77% of patients had neurological deficit. Binary logistic regression showed that older age at surgery (p = 0.03) and associated spinal anomalies (p = 0.04) were significant predictors of deficits. Chiari type II malformation was significantly (p < 0.001) and hydrocephalus was marginally (p = 0.06) more common in patients with myelocystocele-type lesions. The rate of Chiari malformation type II was higher in patients with upper-level lesions (p = 0.02). Patients with cervical saccular LDM had better outcome compared with those patients with true myelomeningocele in more distal areas. According to the current series, most patients obtained ambulation and voiding continence, regardless of the level or type of lesion. Hydrocephalus, Chiari type II malformation, and neurological deficit were more common in patients with myelocystocele-type lesions.

Historically, the presence of gray matter heterotopia was a concern for adverse postnatal neurocognitive status in patients undergoing fetal closure of open spinal dysraphism. The purpose of this study was to evaluate neurodevelopmental outcomes and the onset of seizures during early childhood in patients with a prenatal diagnosis of myelomeningocele/myeloschisis (MMC) and periventricular nodular heterotopia (PVNH). All patients evaluated at the Center for Fetal Diagnosis and Treatment with a diagnosis of MMC between June 2016 to March 2023 were identified. PVNH was determined from prenatal and/or postnatal MRI. The Bayley Scales of Infant and Toddler Development (edition III or IV) were used for neurodevelopmental assessments. Patients were screened for seizures/epilepsy. Of 497 patients evaluated with a prenatal diagnosis of MMC, 99 were found to have PVNH on prenatal MRI, of which 35 had confirmed PVNH on postnatal imaging. From the 497 patients, 398 initially did not exhibit heterotopia on prenatal MRI, but 47 of these then had confirmed postnatal PVNH. The presence of PVNH was not a significant risk factor for postnatal seizures in early childhood. The average neurodevelopmental scores were not significantly different among heterotopia groups for cognitive, language, and motor domains. The presence of PVNH in patients with a prenatal diagnosis of MMC does not indicate an increased risk for neurodevelopmental delay at 1 year of age. We did not demonstrate an association with seizures/epilepsy. These findings can aid clinicians in prenatal consultation regarding fetal repair of open spinal dysraphism. Long-term follow-up is required to discern the true association between PVNH seen on prenatal imaging and postnatal seizures/epilepsy and neurodevelopmental outcomes.

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.

OBJECTIVE Since the entity limited dorsal myeloschisis (LDM) was proposed, numerous confusing clinical cases have been renamed according to the embryopathogenesis. However, clinical application of this label appears to require some clarification with regard to pathology. There have been cases in which all criteria for the diagnosis of LDM were met except for the presence of a neural component in the stalk, an entity the authors call "probable" LDM. The present study was performed to meticulously review these cases and suggest that a modified surgical strategy using limited laminectomy is sufficient to achieve the surgical goal of untethering. METHODS The authors retrospectively reviewed the imaging findings, operative notes, and pathology reports of spinal dysraphism patients with subcutaneous stalk lesions who had presented to their institution between 2010 and 2014. RESULTS Among 33 patients with LDM, 13 had the typical nonsaccular lesions with simple subcutaneous stalks connecting the skin opening to the spinal cord. Four cases had "true" LDM meeting all criteria for diagnosis, including pathological confirmation of CNS tissue by immunohistochemical staining with glial fibrillary acidic protein. There were also 9 cases in which all clinical, imaging, and surgical findings were compatible with LDM, but the "neural" component in the resected stalk was not confirmed. For all the cases, limited exposure of the stalk was done and satisfactory untethering was achieved. CONCLUSIONS One can speculate based on the initial error of embryogenesis that if the entire stalk were traced to the point of insertion on the cord, the neural component would be proven. However, this would require an extended level of laminectomy/laminotomy, which may be unnecessary, at least with regard to the completeness of untethering. Therefore, the authors propose that for some selected cases of LDM, a minimal extent of laminectomy may suffice for untethering, although it may be insufficient for diagnosing a true LDM.