To describe prenatal imaging findings and postnatal outcomes in fetuses diagnosed with saccular forms of closed spinal dysraphism (CSD). This retrospective single-centre study included fetuses diagnosed with non-genetic, non-syndromic CSD between January 2018 and June 2023. Prenatal ultrasound and MRI findings were reviewed, with postnatal outcomes assessed in those managed expectantly, focusing on neurosurgical interventions, motor function, and urologic and bowel outcomes. Eighteen cases were identified; twelve opted for expectant management and had postnatal follow-up. The most common lesion was dysraphic spinal cord lipoma (10/18, 55.6%), followed by limited dorsal myeloschisis (3/18, 16.7%), myelocystocele (3/18, 16.7%) and meningocele (2/18, 11.0%). Chiari malformation and related brain abnormalities were absent at the time of diagnosis in all cases. Most fetuses (88.9%, 16/18) had a low-lying conus medullaris, and 70.6% (12/17) had a sac wall thickness ≥ 2 mm. Postnatally, 75% (9/12) underwent surgical detethering. At ≥ 30 months, all children could walk independently with or without orthoses. However, urologic complications were common in children age ≥ 48 months: 80% (4/5) required clean intermittent catheterization (CIC), 60% (3/5) had urinary incontinence, and 40% (2/5) experienced bowel incontinence. Prenatal imaging features at the lesion level are key for diagnosing CSD. While motor outcomes are favorable, urologic and bowel dysfunctions are frequent in postnatal life.

Limited dorsal myeloschisis (LDM) is a condition in which the separation of the neuroectoderm from the cutaneous ectoderm during primary neural tube formation results in localized disjuncture, causing a continuous cord-like connection and spinal cord tethering. We reported a case of cervical LDM with a wart-like cutaneous appendage that was treated with excision after long-term follow-up. The patient was an 18-year-old girl. A wart-like cutaneous appendage was noted over the nape of the neck since birth. Computed tomography showed spina bifida in the cervical and thoracic spines, and spinal magnetic resonance imaging (MRI) showed a cervical skin lesion and an enlarged dural sac in the dorsal thoracic spinal cord. At 18 years of age, the patient occasionally experienced numbness in her left hand and was referred to our outpatient clinic due to a new high signal intensity in the dorsal cervical spinal cord on a T2-weighted MRI. The MRI showed that a cord-like object was continuous intradural and dorsal to the spinal cord from a cutaneous lesion in the median cervical region, with a high signal in the same region. Symptomatic cervical spinal cord tethering due to a cord-like material was diagnosed, and the patient underwent resection. During surgery, the tract was removed from the cutaneous lesion into the dura mater as a single mass and untethered in the dorsal spinal cord. The histological diagnosis was a pseudo-dermal sinus tract with no luminal structures or neural tissue present, as the cord-like substance was connective tissue containing small blood vessels. Based on the neuroimaging and pathological findings, the patient was diagnosed with cervical LDM. Neurological symptoms improved postoperatively. Herein, we reported a case of cervical LDM that was treated after long-term follow-up. The patient's symptoms improved immediately after surgery. Cervical LDMs are rare, and the timing of surgery for LDM should be considered according to the patient's condition.

Saccular limited dorsal myeloschisis is a condition in which the spinal cord is tethered by a fibroneural stalk that links the cord to a saccular skin lesion, probably due to a small segmental failure of the disjunction between the neural and cutaneous ectoderm during primary neurulation. We previously reported that the dorsally bent cord deviated from the canal into the sac when the tethering effect of the limited dorsal myeloschisis stalk was strong. These cases of saccular limited dorsal myeloschisis should be prenatally differentiated from myelomeningoceles; however, this is complicated by the limited resolution of prenatal magnetic resonance imaging. Nevertheless, postnatal magnetic resonance imaging, including three-dimensional heavily T2-weighted imaging, to demonstrate the stalk linking the top of the bent cord to the sac dome is essential. We recently treated a patient who presented with a cord deviation to the sac due to a short stalk linking the rostral part of the bent cord to the base of the sac. While the sagittal and axial views of three-dimensional heavily T2-weighted imaging alone were insufficient to visualize the short stalk, the coronal view clearly demonstrated that the stalk ran almost parallel to it. During surgery, untethering the cord and completely returning it to the canal is important.

Limited dorsal myeloschisis (LDM) is caused by a primary neurulation defect resulting from incomplete disjunction of the cutaneous and neural ectoderm, and manifests as a fibroneural tethering stalk linking the skin lesion to the underlying spinal cord. We present a case of cervical LDM associated with a multi-lobular cystic lesion suspected during the prenatal ultrasonographic check-up. A diaphanous membranous cystic sac without neuronal components inside was extruded from the dorsal cervical vertebrae at the C6/7 portion. The preoperative diagnosis was confirmed by computed tomography (CT), and the lesion was successfully removed. The membranous sac with arachnoid tissue was extruded from the dural defect without direct connection with fibroneural tissue, suggesting incomplete LDM. We report the clinical characteristics of this rare entity along with a literature review.

Limited dorsal myeloschisis (LDM) is a rare closed neural tube defect characterized by the presence of a fibroneural rod connecting the spinal cord to the skin, and a focal closed skin defect. Distinguishing between open and closed forms of dysraphism is a major challenge, given their variable prognosis. However, the diagnosis of LDM in the antenatal period is difficult and the prognosis of children is little studied, although these data are vital in order to establish suitable prenatal advice and provide couples with the best possible support. We conducted a retrospective multicenter observational study from May 2010 to March 2023 on 5 reference centers attached to a prenatal diagnosis center: the university hospital centers (CHU) of Besançon, Dijon, Nancy, Reims and Strasbourg. A total of 21 cases of LDM suspected on reference ultrasonography were included. The ultrasound criteria used were standardized and corresponded to those described in the literature. In 76% of cases, MRI was performed to complement the obstetrical ultrasound. Amniocentesis was performed in over 50% of cases, and was always normal. Of the 21 cases initially suspected prenatally, there were 17 live births: 9 confirmed cases of LDM (52.9%) and 8 invalidated cases (47.1%), corresponding to another diagnosis. Of the 9 confirmed cases of LDM, 8 were isolated forms, and 1 was associated with a polymalformative syndrome (VACTERL). On reference ultrasonography, there were no significant differences in criteria between confirmed and invalidated LDM, apart from the fibroneural stalk described sonographically in 2 cases, both confirmed postnatally. Concerning the spinal level, there was a difference in involvement, with a predominance of the lumbar level in confirmed cases of LDM, whereas a sacral level was preferred among infirm cases. MRI was carried out in 76% of cases, and confirmed the diagnosis of LDM in 71% of confirmed cases in the postnatal period. Of the 5 requests for medical termination of pregnancy (MTP), 3 were accepted, but 2 were refused by the CPDPN. These two cases corresponded to a confirmed postnatal isolated LDM and a lipomyelomeningocele, both with a favorable prognosis and evolution. Postnatal follow-up averaged 32 months. No notable neurological abnormalities were noted. In terms of bladder and bowel function, urinary tract infections and constipation were common but rare (n=3/6; 50%) and not severe. No significant psychomotor retardation was reported. The 8 cases of invalidated LDM all corresponded to closed dysraphism. No diagnosis was corrected to open dysraphism. In contrast to myelomeningocele, our study confirms that limited dorsal myeloschisis (LDM) tends to have a good prognosis. However, given the risk of postnatal symptoms, particularly sphincter symptoms, management must be early and multidisciplinary. The place of MTP seems questionable. Prenatal counseling must be adapted in the light of these results, after multidisciplinary discussion, in order to communicate clear and appropriate information to future parents.