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To estimate the significance of the association between mid-trimester maternal serum alpha-fetoprotein (MSAFP) level and fetal neuroanatomic findings in cases of open neural tube defect (ONTD).Retrospective study of patients referred for prenatal ONTD repair between 2012 and 2018. Cases were classified into three groups based on their MSAFP level: 1)High MSAFP (3.8MoM - n = 22), 2)Moderately high MSAFP (≤3.8 and ≥2.5MoM - n = 28), 3)Normal MSAFP (2.5MoM - n = 18). MRI scans at the time of referral were used to assess the relationship between MSAFP and: A)Type of ONTD; B) Ventriculomegaly; C) Size of the myeloschisis lesion; D) Volume of myelomeningocele; E) Anatomical level of the lesion (LL).Having a high MSAFP level was more likely to be associated ventriculomegaly at mid-gestation than a moderately high or normal MSAFP level (OR = 8.4;CI95[0.9-73.4];p = 0.05 and OR = 2.8;CI95[0.9-8.8];p = 0.07). There were no differences between the three groups regarding type of lesion, size of the myeloschisis lesion, anatomic LL, or volume of the myelomeningocele sac. Myeloschisis cases with normal MSAFP had a larger surface area when compared to myeloschisis cases with moderately high MSAFP (219.8[104.4-551] vs 155.4[38.5-502.4] mm², p = 0.04).A 2nd trimester MSAFP level3.8MoM in a fetus with ONTD is associated with mid-gestation ventriculomegaly.

Spinal dysraphic lesions due to focal nondisjunction in primary neurulation are commonly encountered in paediatric neurosurgery, but the “fog-of-war” on these conditions was only gradually dispersed in the past 10 years by the works of the groups led by the senior author and Prof. Kyu-Chang Wang. It is now clear that limited dorsal myeloschisis and congenital spinal dermal sinus tract are conditions at the two ends of a spectrum; and mixed lesions of them with various configurations exist. This review article summarizes the current understanding of these conditions’ embryogenetic mechanisms, pathological anatomy and clinical manifestations, and their management strategy and surgical techniques.

Background Open spina bifida (OSB) is one of the most common congenital central nervous system defects and leads to long-term physical and cognitive disabilities. Open fetal surgery for OSB improves neurological outcomes and reduces the need for ventriculoperitoneal shunting, compared to postnatal surgery, but is associated with a significant risk of prematurity and maternal morbidity. Fetoscopic surgery comes with less maternal morbidity, yet the question remains whether the procedure is neuroprotective and reduces prematurity. Comparison of outcomes between different treatment options is challenging due to inconsistent outcome reporting. We aim to develop and disseminate a core outcome set (COS) for fetal OSB, to ensure that outcomes relevant to all stakeholders are collected and reported in a standardised fashion in future studies. Methods The COS will be developed using a validated Delphi methodology. A systematic literature review will be performed to identify outcomes previously reported for prenatally diagnosed OSB. We will assess maternal (primary and subsequent pregnancies), fetal, neonatal and childhood outcomes until adolescence. In a second phase, we will conduct semi-structured interviews with stakeholders, to ensure representation of additional relevant outcomes that may not have been reported in the literature. We will include patients and parents, as well as health professionals involved in the care of these pregnancies and children (fetal medicine specialists, fetal surgeons, neonatologists/paediatricians and allied health). Subsequently, an international group of key stakeholders will rate the importance of the identified outcomes using three sequential online rounds of a modified Delphi Survey. Final agreement on outcomes to be included in the COS, their definition and measurement will be achieved through a face-to-face consensus meeting with all stakeholder groups. Dissemination of the final COS will be ensured through different media and relevant societies. Discussion Development and implementation of a COS for fetal OSB will ensure consistent outcome reporting in future clinical trials, systematic reviews and clinical practice guidelines. This will lead to higher quality research, better evidence-based clinical practice and ultimately improved maternal, fetal and long-term childhood outcomes. Trial registration International Prospective Register of Systematic Reviews (PROSPERO) CRD42018104880. Registered on December 5, 2018. Core Outcome Measures in Effectiveness Trials (COMET): 1187

Some types of spinal dysraphism can be accompanied by extraspinal cysts, including myelomeningocele, myelocystocele, myelocele, meningocele, limited dorsal myeloschisis, lipomyelomeningocele, and terminal myelocystocele. Each disease is classified according to the developmental mechanism, embryologic process, site of occurrence, or internal structure of the extraspinal cyst. In most cystic spinal dysraphisms except meningocele, part of the spinal cord is attached to the cyst dome. Most open spinal dysraphisms pose a risk of infection and require urgent surgical intervention, but when the cyst is accompanied by closed spinal dysraphism, the timing of surgery may vary. However, if the extraspinal cyst grows, it aggravates tethering by pulling the tip of the cord, which is attached to the dome of the cyst. This causes neurological deficits, so urgent surgery is required to release the tethered cord.

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.

Objectives: The aim of the study was to report a subtype of dysraphism designated as myelic limited dorsal malformation (MyeLDM) and to describe its characteristics at prenatal ultrasound (US). Methods: It was a retrospective study from 2014 to 2020 based on second-line US evaluation of patients referred to our institution for myelomeningocele (MMC). Magnetic resonance imaging and acetylcholine esterase evaluation in the amniotic fluid were also offered. Major and minor criteria for open and closed dysraphism were defined and recorded for each patient. Patients were included as MyeLDM when both criteria of closed and open dysraphism were observed in the same fetus. Correlations were obtained with the postpartum data. Results: Twenty patients fulfilled the inclusion criteria, some of them being very close to MMC, others very close to limited dorsal myeloschisis (LDM), and others lying in between. There were 13 live-born neonates and 7 terminations of pregnancy. Correlations between prenatal and postpartum data were overall very good. Conclusion: Our series describe the ultrasonographic characteristics of an intermediate type of dysraphism and suggest that there is a continuum between MMC and LDM with numerous possibilities of hybrid forms (MyeLDM) sharing characteristics of both open and closed dysraphisms.

Background: Closed spinal dysraphism of primary neurulation failure could be associated with filar anomalies, such as filar lipoma or thickened and tight filum terminale (TFT), resulting from impaired secondary neurulation. Retained medullary cord (RMC) is a remnant of the cavitary medullary cord originating from the secondary neurulation failure. Some filar lipomas are known to contain a central canal-like ependyma-lined lumen with surrounding neuroglial tissues (E-LC w/NGT), that is, a characteristic histopathology of RMC. To clarify the embryological background of these filar anomalies, we evaluated the histopathological findings. Methods: Among 41 patients with lesions of primary neurulation failure who underwent initial untethering surgery, the filum including cord-like structure (C-LS) was additionally resected in 10 patients (five dorsal and transitional lipomas; five limited dorsal myeloschisis). We retrospectively analyzed the clinical, neuroradiological, intraoperative, and histopathological findings. Results: Among 10 patients, two patients were diagnosed with RMC based on morphological features and intraoperative neurophysiological monitoring. The diagnosis of filar lipoma was made in six patients, since various amounts of fibroadipose tissue were histopathologically noted in the filum. Two patients were diagnosed with TFT, since the filum was composed solely of fibrocollagenous tissue. E-LC w/NGT was noted not only in both C-LSs of RMCs but also in two out of six fila both with filar lipomas and fila with TFTs. Conclusion: These findings provide further evidence for the idea that entities, such as filar lipoma, TFT, and RMC, can be considered consequences of a continuum of regression failure occurring during late secondary neurulation.

International audience; Introduction: - Open fetal myelomeningocele (MMC) surgery is currently the standard of care option for prenatal MMC repair. We described the population referred to our center and reviewed outcome after open fetal MMC repair.Material and methods: - All patients referred to our center for MMC were reviewed from July 2014 to June 2020. For all the patients who underwent fetal MMC repair, surgical details, maternal characteristics and data from the neonatal to the three-years-old evaluations were collected.Results: - Among the 126 patients referred to our center, 49.2% were eligible and 27.4% (n=17) of them underwent fetal MMC repair. Average gestational age at fetal surgery was 24+6 weeks. There was no case of fetal complication and the only maternal complication was one case of transfusion. We recorded 70% of premature rupture of membranes and 47% of premature labor. Average gestational age at delivery was 34+2 weeks and no patient delivered before 30 weeks. There was no case of uterine scar dehiscence or maternal complication during cesarean section. After birth, 59% of the children had a hindbrain herniation reversal. At 1-year-old, 42% were assigned a functional level of one or more better than expected according to the prenatal anatomic level and 25% required a ventriculoperitoneal shunt. At 3-year-old, all the children attended school and 75% were able to walk with orthotics or independently.Conclusion: - Open fetal surgery enables anatomical repair of the MMC lesion, a potential benefit on cerebral anomalies and motor function, with a low rate of perinatal and maternal complications.

OBJECTIVE: A trial comparing prenatal with postnatal open spina bifida (OSB) repair established that prenatal surgery was associated with better postnatal outcome. However, in the trial, fetal surgery was carried out through hysterotomy. Minimally invasive approaches are being developed to mitigate the risks of open maternal-fetal surgery. The objective of this study was to investigate the impact of a novel neurosurgical technique for percutaneous fetoscopic repair of fetal OSB, the skin-over-biocellulose for antenatal fetoscopic repair (SAFER) technique, on long-term postnatal outcome. METHODS: This study examined descriptive data for all patients undergoing fetoscopic OSB repair who had available 12- and 30-month follow-up data for assessment of need for cerebrospinal fluid (CSF) diversion and need for bladder catheterization and ambulation, respectively, from eight centers that perform prenatal OSB repair via percutaneous fetoscopy using a biocellulose patch between the neural placode and skin/myofascial flap, without suture of the dura mater (SAFER technique). Univariate and multivariate logistic regression analyses were used to examine the effect of different factors on need for CSF diversion at 12 months and ambulation and need for bladder catheterization at 30 months. Potential cofactors included gestational age at fetal surgery and delivery, preoperative ultrasound findings of anatomical level of the lesion, cerebral lateral ventricular diameter, lesion type and presence of bilateral talipes, as well as postnatal findings of CSF leakage at birth, motor level, presence of bilateral talipes and reversal of hindbrain herniation. RESULTS: A total of 170 consecutive patients with fetal OSB were treated prenatally using the SAFER technique. Among these, 103 babies had follow-up at 12 months of age and 59 had follow-up at 30 months of age. At 12 months of age, 53.4% (55/103) of babies did not require ventriculoperitoneal shunt or third ventriculostomy. At 30 months of age, 54.2% (32/59) of children were ambulating independently and 61.0% (36/59) did not require chronic intermittent catheterization of the bladder. Multivariate logistic regression analysis demonstrated that significant prediction of need for CSF diversion was provided by lateral ventricular size and type of lesion (myeloschisis). Significant predictors of ambulatory status were prenatal bilateral talipes and anatomical and functional motor levels of the lesion. There were no significant predictors of need for bladder catheterization. CONCLUSION: Children who underwent prenatal OSB repair via the percutaneous fetoscopic SAFER technique achieved long-term neurological outcomes similar to those reported in the literature after hysterotomy-assisted OSB repair. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Objective Recognition of congenital tethered cervical cord in adults and literature review. Methods Retrospective review of adult onset tethered cervical cord patients (age >20 years). Results Three adults were identified; 2 women and 1 man, average age 47 years. The presenting symptoms were neck pain with restricted movement (3), quadriparesis (2), and sensory changes (2). Hyperreflexia was present in all three. Bony abnormalities were mainly bifid cervical spinous processes (3), with Klippel-Feil abnormalities in 1. The neurocutaneous stigmata was seen in 2. Magnetic resonance imaging revealed “limited dorsal myeloschisis” in all 3 patients. The dorsal aspect of the cervical cord extruded into the tract leading to the surface. Conclusions Neurocutaneous stigmata should not be considered benign. A missed clinical diagnosis was apparent in all 3 patients; 2 of whom underwent surgery with excellent results. Magnetic resonance imaging can identify the abnormal cervical cord protruding towards the “sinus tract” and allow planning to avert injury to the spinal cord during release.

Case series summary The aim of this case series was to describe the clinical presentation, imaging findings and histopathology of three cats with limited dorsal myeloschisis (LDM). The history, examination and MRI sequences were reviewed in three cases presented to a single referral hospital. The surgery report and histopathology were described in two cases. All cats were young (10 weeks old, 5 months old, 4 years old), presenting with varying degrees of progressive paraparesis. All had a midline skin defect overlying the spinal column that was either sunken or saccular, containing fluid thought to be cerebrospinal fluid. MRI sequences demonstrated tissue extending from the dura through an overlying bifid spinous process and attached to the dermis, with associated spinal cord tethering, atrophy and syringomyelia. Lesions were located at L2–L3, T8–T9 and L4. Histopathology described a fibroneural stalk with a glio-ependymal lining, surrounded by glial nests and nerve fibres. The youngest and most severely affected was euthanased, while the other two underwent surgery. Both regained independent ambulation with persistent paraparesis; however, one required ongoing management of urinary incontinence. Relevance and novel information LDM is a primary neural tube defect that may result in neurological deficits, including bladder dysfunction, and is characterised by a fibroneural stalk between the dermis and the spinal cord. Distinct MRI features, such as a visible intrathecal tract, dorsally tethered cord and syringomyelia, help distinguish this condition from the clinically similar dermoid sinus. The presence of progressive neurological signs, with a palpable midline defect overlying the affected spinal cord segment, may raise suspicion for this clinical entity in veterinary patients.

Amniotic band syndrome (ABS) has been known since ancient times. Descriptions in modern medicine have occurred since the mid-nineteenth century. The association of the amniotic band syndrome with tethered cord is rare. It was generally thought to be incompatible with life. Of late, with better imaging, there have been case reports of amniotic bands causing cord tethering in neurosurgical literature, but its association with limited dorsal myeloschisis has hitherto not been described. We report a case of amniotic band syndrome (ABS) associated with a cervical limited dorsal myeloschisis (LDM) in a child of 2 and a half years old. The management of LDM in ABS is essentially the same as in isolated cases.

OBJECTIVE We have described previously our percutaneous fetoscopic technique for the treatment of open spina bifida (OSB). However, approximately 20-30% of OSB defects are too large to allow primary skin closure. Here we describe a modification of our standard technique using a bilaminar skin substitute to allow closure of large spinal defects. The aim of this study was to report our clinical experience with the use of a bilaminar skin substitute and a percutaneous fetoscopic technique for the prenatal closure of large OSB defects. METHODS Surgery was performed between 24.0 and 28.9 gestational weeks with the woman under general anesthesia, using an entirely percutaneous fetoscopic approach with partial carbon dioxide insufflation of the uterine cavity, as described previously. If there was enough skin to be sutured in the midline, only a biocellulose patch was placed over the placode (single-patch group). In cases in which skin approximation was not possible, a bilaminar skin substitute (two layers: one silicone and one dermal matrix) was placed over the biocellulose patch and sutured to the skin edges (two-patch group). The surgical site was assessed at birth, and long-term follow-up was carried out. RESULTS Percutaneous fetoscopic OSB repair was attempted in 47 consecutive fetuses, but surgery could not be completed in two. Preterm prelabor rupture of membranes (PPROM) occurred in 36 of the 45 (80%) cases which formed the study group, and the mean gestational age at delivery was 32.8 ± 2.5 weeks. A bilaminar skin substitute was required in 13/45 (29%) cases; in the remaining 32 cases, direct skin-to-skin suture was feasible. There were 12 cases of myeloschisis, of which 10 were in the two-patch group. In all cases, the skin substitute was located at the surgical site at birth. In five of the 13 (38.5%) cases in the two-patch group, additional postnatal repair was needed. In the remaining cases, the silicone layer detached spontaneously from the dermal matrix (on average, 25 days after birth), and the lesion healed by secondary intention. The mean operating time was 193 (range, 83-450) min; it was significantly longer in cases requiring the bilaminar skin substitute (additional 42 min on average), although the two-patch group had similar PPROM rate and gestational age at delivery compared with the single-patch group. Complete reversal of hindbrain herniation occurred in 68% of the 28 single-patch cases and 33% of the 12 two-patch cases with this information available (P

Limited dorsal myeloschisis (LDM) is characterized by two invariable features: a focal closed neural tube defect and a fibroneural stalk linking the skin lesion to the underlying spinal cord. Although detailed histopathological findings of the LDM stalk were originally described by Pang et al., the precise relationship between the histopathological findings and clinical manifestations including intraoperative findings has not been fully determined. We retrospectively analyzed the histopathological findings of the almost entire stalk and their relevance to the clinical manifestations in six Japanese LDM patients with flat skin lesions. Glial fibrillary acidic protein (GFAP)-immunopositive neuroglial tissues were observed in three of the six patients. Unlike neuroglial tissues, peripheral nerve fibers were observed in every stalk. In four patients, dermal melanocytosis, “Mongolian spot,” was seen surrounding the cigarette-burn lesion. In three of these four patients, numerous melanocytes were distributed linearly along the long axis of the LDM stalk, which might represent migration of melanocytes from trunk neural crest cells during formation of the LDM stalk. Immunopositivity for GFAP in the LDM stalk was observed in as few as 50% of our patients, despite the relatively extensive histopathological examination. We confirm that the clinical diagnosis of LDM should be made based on comprehensive histopathological examination as well as clinical manifestations. The profuse network of peripheral nerve fibers in every stalk and the high incidence of melanocyte accumulation associated with dermal melanocytosis might assist the histopathological diagnosis of LDM.

After publication of the Management of Myelomeningocele Study (MOMS) there is confusion regarding which treatment of open neural tube defects (NTD) is best. We report our results of postnatally repaired open NTDs born between 2007–2018 (n = 36) in critical reflection of the MOMS study. Neurosurgical, orthopedic, and urologic data were assessed. We also introduce a new entity: “status post prenatal repair”. FU ranged from 29 to 161 months (mean: 89.1 m) in 7 cases of myeloschisis and 24 myelomeningoceles in the final collective n = 31. The shunt rate was 41.9%, and the endoscopic third ventriculostomy rate was 16.1%. Hydrocephalus requiring treatment was not associated with the anatomical level, but with premature birth (p = 0.048). Myeloschisis was associated with shunt placement (p = 0.008). ROC analysis revealed birth &lt, 38.5th week predicts the necessity for hydrocephalus treatment (sensitivity: 89%, specificity: 77%, AUC= 0.71, p = 0.055). Eight (25.8%), patients are wheelchair-bound, 2 (6.5%) ambulate with a posterior walker, 10 (32.3%) with orthosis and 11 (35.5%) independently. One (3.2%) patient underwent detethering at 5.5 years. A total of three patients underwent five Chiari decompressions (9.6%). Further, nineteen orthopedic procedures were performed in nine patients (29.0%). A total of 17 (54.8%) patients self-catheterize, which was associated with an anatomical lesion at L3 or below (p = 0.032) and 23 (74.2%) take anticholinergic medication. In conclusion, shunt dependency is associated with myeloschisis, not with the anatomical defect level. Hydrocephalus treatment is associated with premature birth. In this postnatal cohort with significantly longer follow-up data than the MOMs study, the ambulation rate is better, the shunt rate lower and the secondary tethered cord rate better compared to the MOMS study.

Diagnosis of fetal spinal dysraphism is a challenge. It is difficult to distinguish between a meningocele, myelomeningocele, and a recently described entity called limited dorsal myeloschisis (LDM). Although myelomeningocele is associated with a poor prognosis, LDM can have a good outcome. We present a case of prenatally diagnosed LDM. Because sonographic examination revealed a round, cystic, septated cervical mass without associated cerebral anomalies, the lesion was initially considered an isolated meningocele. Fetal MRI contributed to correct the diagnosis. A diagnostic error can lead to the wrong surgical support or even the termination of pregnancy. Therefore, we highlight the importance of fetal MRI in such cases, particularly when no cerebral abnormalities are observed on sonographic examination.

OBJECTIVESince 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.METHODSThe 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.RESULTSAmong 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.CONCLUSIONSOne 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.

Imaging of occult spinal dysraphism (OSD) has evolved significantly over the recent years. The preferred imaging modality of choice for most, if not all, lesions is MRI. In this chapter, we review imaging of five clinically relevant OSDs: low conus medullaris, dermal sinus tract, lipomyelomeningocele, neurenteric cyst, and split cord malformation. In each section, we take the opportunity to explore related topics. In the first section, the topics of nondiagnostic imaging in tethered cord syndrome, incidental fatty fila, and evaluation of the sacral dimple are discussed. The next section, on dermal sinus tracts, includes a discussion about related diagnoses, including the newer diagnostic entity of limited dorsal myeloschisis (LMD) and the more historical meningocele manque (MM). A third section discusses the imaging characteristics of lipomyelomeningocele, with a subsection on related diagnoses such as meningocele and myelocele. After discussions about neurenteric cysts (NECs) and split cord malformations (SCMs), we discuss future directions for imaging of OSD.

Spina bifida is a birth defect that occurs due to the disruption of the formation of the neural tube with an incidence of 1–10 cases per 1000 live births. Spina bifida can appear as an occulta or aperta type, and the latter consists of meningocele, myelomeningocele, and myeloschisis. We reported a case of a term male newborn who was presented with lethargic, bradypnea, suction reflex abnormalities, and paralysis of lower extremities. A defect was found in the spine in the thoracolumbar region showed a placode with no meningeal and skin covering, suggestive of a myeloshisis. The patient was treated in the neonatal intensive care unit, was placed on non-invasive ventilation with successful weaning, parenteral nutrition, systemic antibiotics regimen, and wound care. The patient was consulted with a neurosurgeon and was subjected to an ultrasound examination of the head that led to hydrocephalus. After experienced clinical improvement and oral tolerance, the patient was allowed for discharged and scheduled for surgery.

Introduction Limited dorsal myeloschisis (LDM) is a rare form of spinal dysraphism that is characterised by a distinctive fibroneural stalk connecting the spinal cord to the overlying skin lesion. The skin lesions associated with LDM can appear benign clinically and careful evaluation with an MRI scan is essential for diagnosing LDM and to differentiate this entity from other forms of spinal dysraphism and benign causes of skin lesions. Research question There is a lack of reported atlantoaxial LDM in the literature. We sought to report the clinical presentation, radiological features and surgical management of the first two reported atlantoaxial LDM. Material and methods Clinical findings and radiological images of the two cases of atlantoaxial LDM that underwent surgical intervention at our institution were retrieved from the medical notes, operative records and imaging system. Results Both cases of atlantoaxial LDM (C0-1 and C1-2 respectively) underwent successful resection of the overlying cutaneous lesions and stalks to release the tethered spinal cords. Discussion The surgical management of LDM have been associated with good outcomes and consists of resecting the fibroneural stalk close to the underlying cord, releasing the tethered spinal cord and removing the overlying cutaneous lesion. Conclusion These are the first two reported cases of atlantoaxial LDM in the literature. We aim to raise awareness of this pathological entity and highlight the importance of establishing the correct diagnosis to guide definitive management, and report the favourable neurological outcome in these cases despite the rostral location.

Objective: To determine the ultrasonographic characteristics of limited dorsal myeloschisis (LDM) at prenatal ultrasound (US) and to highlight the main features that may help differentiate LDM and myelomeningocele (MMC). Methods: In a tertiary reference center in fetal medicine, we prospectively collected the medical data and ultrasonographic characteristics of all patients referred for in utero prenatal repair of MMC between November 1, 2013 and April 30, 2015. Results: Among the 29 patients assessed, the diagnosis of MMC was revised in 7 cases. In 6 cases, the diagnosis of LDM was established. On US scan, LDM was characterized by a spinal saccular lesion with a thick peripheral lining in continuity with the adjacent skin. Within the saccular lesion, a thick hyperechoic well-delineated structure was present in continuity with the spinal cord. Cerebral structures were normal except for 2 cases showing a cisterna magna slightly decreased in size. In the remaining 22 cases MMC was confirmed, with cerebral anomalies present in 21/22 cases (95.5%). Conclusion: LDM is a form of closed dysraphism accessible to prenatal diagnosis by US that may mimic MMC. Considering the major difference in prognosis between these two entities, physicians should be aware of the existence and ultrasonographic characteristics of LDM.

The purpose of this study was to examine differences between patients with myelomeningocele and those with myelocele with respect to brain imaging findings at fetal MRI.A single-center retrospective analysis was performed of fetal MRI examinations revealing open spinal dysraphism from 2004 through 2016 with available diagnostic postnatal spinal MR images in conjunction with neurosurgical follow-up findings. Images were reviewed by two board-certified fellowship-trained pediatric neuroradiologists. Relevant clinical data were recorded.The study included 119 fetal MRI examinations of patients with open spinal dysraphism. Myeloceles were found in 29.4% (35/119) of these examinations and myelomeningoceles in the others. All (35/35) myeloceles showed grade 3 (severe) Chiari II malformations. Only 73.8% (62/84) of myelomeningoceles showed grade 3 Chiari II malformation. Clinically significant spinal kyphosis was found in 5.0% (6/119) of fetuses, and all of these fetuses had grade 3 Chiari II malformations. The size of the spinal dysraphic defect had significant positive correlation with lateral (p0.0001) and third (p = 0.006) ventricular size. Mean volume of the myelomeningocele sac was significantly different among Chiari II grades and inversely proportional to Chiari II grade (p = 0.0009).Larger spinal dysraphic defects correlated with increased ventricular size at fetal MRI. All of the fetuses with myelocele or kyphosis had severe Chiari II malformations. Larger myelomeningocele sac size was associated with lower grade of Chiari II malformation, suggesting that myelomeningocele sac formation may be protective against hindbrain herniation.

This study aims to highlight the recurrent tethered cord syndrome in relation to the relatively new pathological entity of limited dorsal myeloschisis (LDM) and to mention the difficulties faced by the paediatric neurosurgeon in developing countries with reference to LDM which was not recognized at initial presentation. We present three cases of recurrent tethered cord syndrome who were operated early in life (not by paediatric neurosurgeons) as meningoceles and who were then subsequently referred to the senior author as they presented with clinical signs of re-tethering of the cord. The first child of 1 year of age represented with cervicodorsal swelling 10 months after primary surgery for a cervical meningomyelocele done elsewhere on the second day of life. The second was a girl of 3 years of age who was operated at birth and presented with severe brachialgia and neck pain after 2 years. The third was a 19-year-old girl operated at birth presenting with spastic paraparesis and also hand weakness associated with kyphosis. All the three patients improved symptomatically and neurologically after redo surgery. The diagnosis of LDMs, especially in developing countries, is frequently missed. This needs to be tackled and addressed so that children with this subset of neural tube defects, who otherwise would normally have a very good outcome, may not be blighted and left scarred for life at an early age.

The term limited dorsal myeloschisis (LDM) was used by Pang et al. (2010) to describe a distinct clinicopathological entity. LDMs are characterized by two invariable features: a focal-closed neural tube defect and a fibroneural stalk that links the skin lesion to the underlying spinal cord. We retrospectively analyzed the neurosurgical pathologic findings of four LDM patients. Case 1 had a saccular skin lesion with nonterminal abortive myelocystocele at T11–12. Cases 2, 3, and 4 had a non-saccular (flat) skin lesion in the lumbosacral region. The morphologic features of the lesion in case 2 were those of meningocele manque. Cases 3 and 4 had accompanying non-LDM anomalies, caudal-type lipoma and type II split-cord malformation with neurenteric cyst, respectively. At preoperative diagnosis of the LDM stalk, magnetic resonance imaging, including 3D heavily T2-weighted image was useful; however, minute findings were often missed in the complicated cases 3 and 4. All patients had a favorable outcome following untethering of the stalk from the cord. The central histopathological feature of the LDM stalk is neuroglial tissue in the fibrocollagenous band; however, the stalk in cases 2 and 4 did not have glial fibrillary acidic protein-immunopositive neuroglial tissues. Therefore, the diagnosis of LDM should be made based on comprehensive evaluation of histologic and clinical findings.

To describe characteristics of foetuses undergoing in utero repair of open neural tube defects (ONTD) and assess postoperative evolution of posterior fossa and brain morphology. Analysis of pre- and postoperative foetal as well as neonatal MRI of 27 foetuses who underwent in utero repair of ONTD. Type and level of ONTD, hindbrain configuration, posterior fossa and liquor space dimensions, and detection of associated findings were compared between MRI studies and to age-matched controls. Level of bony spinal defect was defined with exactness of ± one vertebral body. Of surgically confirmed 18 myelomeningoceles (MMC) and 9 myeloschisis (MS), 3 MMC were misdiagnosed as MS due to non-visualisation of a flat membrane on MRI. Hindbrain herniation was more severe in MS than MMC (p

In surgery of repair for spina bifida, various skin plastic techniques are sometimes necessary due to large skin defect or subsequent ulcers in cases when approximation on the midline is difficult.A baby was born with a large skin defect due to huge lumbar myeloschisis and kyphosis, which was repaired 2 days after birth using Limberg's skin flap at the peak of kyphosis. Skin ischemia around the tip of the flap gradually enlarged and resulted in a large skin ulcer. We performed negative pressure wound therapy (NPWT) using a Vacuum Assisted Closure (V.A.C.®) therapy system for 4 weeks which shrank the ulcer remarkably. Subsequently, a pedicle skin flap without graft was performed to cover the rest of the ulcer, which adapted well without CSF leakage postoperatively.A combination treatment of NPWT and skin plastic surgery was successfully performed for a very young infant with spina bifida. NPWT could be another useful option for the treatment of ulcer following spina bifida repair surgery, though surgeons should carefully confirm that there is no CSF leakage before and during the procedure.

Introduction: We investigated the correlation of amniotic fluid (AF) concentrations of glial fibrillary acidic protein (GFAP) with prenatal features of myelomeningocele (MMC) and neurodevelopmental outcome after fetal MMC (fMMC) surgery. Materials and Methods: AF was collected during fMMC surgery between December 2012 and November 2015. AF-GFAP concentration was determined by ELISA. Retrospective chart review identified the characteristics of the defect. Data regarding delivery and 1-year neurodevelopmental outcome was collected from The Children's Hospital of Philadelphia fMMC Registry. Results: Eighty-two AF samples were collected from fMMC surgeries. Perinatal data were obtained from 77 subjects, and 1-year follow-up data from 65 subjects. GFAP concentrations were significantly elevated in MMC compared to myeloschisis (24.1 ± 2.9 and 10.3 ± 1.5 ng/mL; p < 0.0001). A larger percentage of subjects with myeloschisis defects delivered before their scheduled due date (myeloschisis 88.5%; MMC 55.0%; p = 0.003) and delivered at an earlier mean gestational age (34.6 ± 0.4 weeks, n = 26) compared to those with MMC defects (35.2 ± 0.4 weeks, n = 51) (p = 0.04). Discussion: AF-GFAP levels differentiate between MMC and myeloschisis, and raise interesting questions regarding the clinical significance between the 2 types of defects.

Limited dorsal myeloschisis (LDM) originates from undisjointed neural and cutaneous ectoderms during primary neurulation. Its hallmark is a fibroneural stalk causing tethering on the dorsal spinal cord rostral to the conus. Its treatment is a relatively straightforward resection of the LDM stalk from the spinal cord. On reviewing our series of 75 cases of LDMs, we found that the majority of LDM stalks have only a glioneuronal core within a fibrous stroma, but a small number have been found to have elements of dermoid cyst or a complete dermal sinus tract either contiguous with the fibroneural stalk or incorporated within its glial matrix, not surprising considering the original continuum of cutaneous and neural ectoderm in LDMs’ embryogenesis. The dermoid element can be microscopic and escape casual observation, but could grow to large intradural dermoid cysts if part of the dermoid invested LDM stalk is left inside the dura. We present our series of LDMs associated with dermoid elements and recommend excising the entire length of the intradural LDM stalk from its dural entry point to its merge point with the spinal cord during the initial treatment to avoid secondary deterioration and additional surgery.

There is an urgent need is for a regenerative patch for in utero repair of spina bifida in situations in which primary closure is difficult.We present two cases of large myeloschisis defects that underwent in utero spina bifida repair at midgestation with closure of the skin defect by using a cryopreserved human umbilical cord patch. The pregnancies were uncomplicated, and the births occurred at 37 weeks by planned cesarean delivery. The repair sites were intact with no evidence of cerebrospinal fluid leakage, with skin regenerated after delivery over a period of 3-4 weeks. The short-term outcomes after delivery showed reversal of hindbrain herniation, minimal spinal cord tethering, and normal function of the lower extremities.Cryopreserved human umbilical cord may be a suitable patch system for the spina bifida closure.

BACKGROUND AND PURPOSE: While limited dorsal myeloschisis is a distinctive form of spinal dysraphism, it may be confused with congenital dermal sinus. The aim of this study was to describe clinical and MR imaging findings of limited dorsal myeloschisis that can distinguish it from congenital dermal sinus. MATERIALS AND METHODS: We retrospectively reviewed the clinical and MR imaging findings of 12 patients with limited dorsal myeloschisis and 10 patients with congenital dermal sinus. Skin abnormalities, neurologic deficits, and infectious complication were evaluated on the basis of clinical information. We evaluated the following MR imaging features: visibility of the tract along the intrathecal course, attachment site of the tract, level of the conus medullaris, shape of the spinal cord, and presence of intradural lesions such as dermoid/epidermoid tumors. RESULTS: A crater covered with pale epithelium was the most common skin lesion in limited dorsal myeloschisis (10/12, 83%). Infectious complications were common in congenital dermal sinus (6/10, 60%), whereas none were found in limited dorsal myeloschisis (P = .003). The following MR imaging findings were significantly different between the 2 groups (P < .05): 1) higher visibility of the intrathecal tract in limited dorsal myeloschisis (10/12, 83%) versus in congenital dermal sinus (1/10, 10%), 2) the tract attached to the cord in limited dorsal myeloschisis (12/12, 100%) versus various tract attachments in congenital dermal sinus, 3) dorsal tenting of the cord in limited dorsal myeloschisis (10/12, 83%) versus in congenital dermal sinus (1/10, 10%), and 4) the presence of dermoid/epidermoid tumors in congenital dermal sinus (6/10, 60%) versus none in limited dorsal myeloschisis. CONCLUSIONS: Limited dorsal myeloschisis has distinct MR imaging features: a visible intrathecal tract with dorsal tenting of the cord at the tract-cord union. Limited dorsal myeloschisis was not associated with infection and dermoid/epidermoid tumors.

This report describes the case of a neonate with myeloschisis weighing 599 g that underwent an operation for spinal cord reconstruction resulting in substantial neuronal functional recovery. At 28 weeks of gestation, oligohydramnios was detected and the female fetus was diagnosed with intrauterine growth retardation. At birth by emergency caesarean section, she showed lumbosacral myeloschisis and complete paralysis of the lower extremities. Surgical repair and spinal cord reconstruction was performed 2 days after birth by closing the neural placode. Total blood loss was only 2 ml. Within 3 months of the operation, lower extremity neurologic function gradually improved down to the level of the knee joint. To our knowledge, this case is the lowest recorded body weight for a neonate with myeloschisis repair at birth, and this further suggests the possibility of improvement of lower extremity neurologic function after birth and surgical reconstruction.

We compared two strategies for treating newborns with myeloschisis or myelomeningocele (open neural tube defect [oNTD]) and hydrocephalus. These strategies involved insertion of a ventriculo-peritoneal shunt (VPS) either synchronous with or sequential to surgical closure of the oNTD. We investigated shunt infection and cerebrospinal fluid (CSF) leakage rates and their effects on the duration of hospitalization for both treatments. The study involved 65 patients with hydrocephalus and open neural placodes which were covered with a thin pseudomembrane. Thirty-eight infants underwent an oNTD repair operation and shunting during the same surgical session (synchronous group [group 1]), and 27 infants underwent sequential procedures, in which shunt insertion was delayed until the thoracolumbar wound was partially healed (sequential group [group 2]). Group 1 had a mean duration of hospital stay of 15.5 days, significantly less than the average 28.8 days of group 2 (p0.05). No significant differences in CSF leakage and shunt infections occurred between the two groups (p0.05). The incidence of shunt infection due to CSF fistulas that developed postoperatively was higher for patients with CSF leakage as a result of oNTD at birth than for patients without CSF leakage (p0.05). Patients with oNTD are at significant risk of infections because of the thin pseudomembrane over the defect. In addition, newborn patients may also have a weakened immune system. Despite these disadvantages, VPS placement within a single session can be advantageous for the patient, family and physician, compared to multiple surgical procedures. It is also more cost-effective.

Background Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characterized by 2 constant features: a focal "closed" midline defect and a fibroneural stalk that links the skin lesion to the underlying cord. The embryogenesis is hypothesized to be incomplete disjunction between cutaneous and neural ectoderms, thus preventing complete midline skin closure and allowing persistence of a physical link (fibroneural stalk) between the disjunction site and the dorsal neural tube. Objective To illustrate these features in 51 LDM patients. Methods All patients were studied with magnetic resonance imaging or computed tomography myelography, operated on, and followed for a mean of 7.4 years. Results There were 10 cervical, 13 thoracic, 6 thoracolumbar and 22 lumbar lesions. Two main types of skin lesion were saccular (21 patients), consisting of a skin-base cerebrospinal fluid sac topped with a squamous epithelial dome, and nonsaccular (30 patients), with a flat or sunken squamous epithelial crater or pit. The internal structure of a saccular LDM could be a basal neural nodule, a stalk that inserts on the dome, or a segmental myelocystocele. In nonsaccular LDMs, the fibroneural stalk has variable thickness and complexity. In all LDMs, the fibroneural stalk was tethering the cord. Twenty-nine patients had neurological deficits. There was a positive correlation between neurological grade and age, suggesting progression with chronicity. Treatment consisted of detaching the stalk from the cord. Most patients improved or remained stable. Conclusion LDM is a distinctive clinicopathological entity and a tethering lesion with characteristic external and internal features. We propose a new classification incorporating both saccular and flat lesions.

The aim of this study was to evaluate three-dimensional Fourier transformation-constructive interference in steady-state (CISS) imaging as a preoperative anatomical evaluation of the relationship between the placode, spinal nerve roots, CSF space, and the myelomeningocele sac in neonates with lumbosacral myeloschisis. Five consecutive patients with lumbosacral myeloschisis were included in this study. Magnetic resonance (MR) CISS, conventional T1-weighted (T1-W) and T2-weighted (T2-W) images were acquired on the day of birth to compare the anatomical findings with each sequence. We also performed curvilinear reconstruction of the CISS images, which can be reconstructed along the curved spinal cord and neural placode. Neural placodes were demonstrated in two patients on T1-W images and in three patients on T2-W images. T2-W images revealed a small number of nerve roots in two patients, while no nerve roots were demonstrated on T1-W images. In contrast, CISS images clearly demonstrated neural placodes and spinal nerve roots in four patients. These findings were in accordance with intraoperative findings. Curvilinear CISS images demonstrated the neuroanatomy around the myeloschisis in one slice. The resulting images were degraded by a band artifact that obstructed fine anatomical analysis of the nerve roots in the ventral CSF space. The placode and nerve roots could not be visualized in one patient in whom the CSF space was narrow due to the collapse of the myelomeningocele sac. MR CISS imaging is superior to T1-W and T2-W imaging for demonstrating the neural placode and nerve roots, although problems remain in terms of artifacts.

Hemimyeloschisis is a very rare congenital malformation of the spine which is characterized by a split cord malformation associated with complete exposureof the one hemicord to the exterior. We report a case of hemimyeloschisis on the right hemicord in a patient with hydrocephalus. The patient was a female neonate with myeloschisis, skin defect, and hypertrichosis visible at birth in the upper lumbar region. There was also skin defect around the myeloschisis. Computed tomography (CT) revealed a bony septum at the L2 level as well as the myeloschisis on the right hemicord, which enabled us to make a precise preoperative diagnosis of this rare malformation. There was also mild hydrocephalus in cranial CT scan. Closure of the myeloschisis and removal of the septum were successfully performed associated with the closure of the skin in one stage surgery to prevent subsequent infection and neurological deterioration. Ventriculoperitoneal shunt insertion was performed for hydrocephalus. The presence of combined split cord malformation and myeloschisis is consistent with the hypothesis of an ontogenic basis of development. This combination also emphasizes the importance of early imaging for diagnosis in this complex malformation.

Split cord malformation (SCM) associated with myeloschisis is a very rare form of spinal dysraphism. We encountered a case of SCM associated with myeloschisis showing split neural placodes (hemicords) in the upper lumbar region.Radiological examinations, including prenatal MRI and postnatal CT scan, clearly demonstrated a bony spur between the two hemicords as well as myeloschisis, which facilitated a precise preoperative diagnosis of this complex anomaly. Resection of the spur, closure of the myeloschisis, and untethering of the thickened filum terminale were successfully accomplished in one stage. The presence of SCM associated with myeloschisis is consistent with the hypothesis of an ontogenic basis of neural development, and we emphasize the importance of early imaging including prenatal MRI for diagnosing this complex anomaly.

We report a case of myeloschisis on the right hemicord in a patient with diastematomyelia. The patient was a female neonate with myeloschisis visible at birth in the upper lumbar region. Radiological examination, including three-dimensional CT and MRI, clearly revealed a bony septum as well as the myeloschisis on the right hemicord, which enabled us to make a precise preoperative diagnosis of this complex anomaly. Closure of the myeloschisis and removal of the septum were successfully accomplished in one stage to prevent subsequent infection and neurological deterioration. The presence of combined diastematomyelia and myeloschisis is consistent with the hypothesis of an ontogenic basis of development and emphasizes the importance of early imaging for diagnosis in this complex anomaly.

Subdural hematoma (SDH) is a well-known sequela of ventriculoperitoneal shunt insertion for hydrocephalus, usually spreads out over the cerebral convexity, and appears as a crescent-shaped lesion on imaging. The authors report the rare case of an infant with a globular SDH, which MR imaging revealed as a round mass lesion. A 13-month-old girl with a history of severe congenital hydrocephalus associated with myeloschisis underwent ventriculoperitoneal shunt placement after repair of myeloschisis and developed convulsive seizure. Magnetic resonance imaging showed a large subdural round mass with a lesion like a pedestal in the left parietal region, suggesting a globular SDH surrounded by a thin cerebral mantle. Because of the seizures and because the hematoma did not respond to a change in valve pressure, the patient underwent a craniotomy to remove the hematoma and to resect the thick outer membranes of multiple layers. Postoperative MR imaging demonstrated the disappearance of the SDH, and no additional shunt complication was observed during a long follow-up period. To the authors' knowledge, this is the first report of a patient with globular SDH published in the literature. The authors postulate that the globular SDH was caused by the thin cerebral mantle associated with severe craniocerebral disproportion, and they discuss the possible mechanisms for this unique formation.

Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characterized by two constant features: a focal "closed" midline skin defect and a fibroneural stalk that links the skin lesion to the underlying cord. The embryogenesis is hypothesized to be incomplete disjunction between cutaneous and neural ectoderms, thus preventing complete midline skin closure and allowing persistence of a physical link (fibroneural stalk) between the disjunction site and the dorsal neural tube.We utilize the experience gained from the management of 63 patients with LDM to illustrate these features.All patients were studied with MRI or CT myelogram, operated on, and followed for a mean of 9.4 years.There were 11 cervical, 16 thoracic, 8 thoracolumbar, and 28 lumbar lesions. Two main types of skin lesion were: saccular (26 patients; consisting of a skin base cerebrospinal fluid sac topped with squamous epithelial dome or a thin membranous sac) and nonsaccular (37 patients; with a flat or sunken squamous epithelial crater or pit). The internal structure of a saccular LDM could be a basal neural nodule, a stalk that inserts on the dome, or a segmental myelocystocoele. In nonsaccular LDMs, the fibroneural stalk has variable thickness and complexity. All fibroneural stalks contain glioneuronal tissues accompanied by variable quantities of nerves and mesodermal derivatives. In all LDMs, the fibroneural stalk was tethering the cord. Twenty-nine patients had neurological deficits. There was a positive correlation between neurological grade and age suggesting progression with chronicity. Treatment consisted of detaching the stalk from the cord. Most patients improved or remained stable. LDMs were associated with three other dysraphic malformations in more than coincidental frequencies: six LDMs were contiguous with dorsal lipomas, four LDMs shared the same tract or traveled in parallel with a dermal sinus tract, and seven LDMs were related to a split cord malformation. The embryogenetic implications of these associations are discussed.LDM is a distinctive clinicopathological entity and a tethering lesion with characteristic external and internal features. We propose a new classification incorporating both saccular and flat lesions.

The classification and embryogenesis of cystic cervical dysraphic lesions are discussed in the light of the authors' experience and review of the literature. It is felt that these lesions are best described as meningoceles or myelocystoceles, and the use of the term 'myelomeningocele' may be more confusing than clarifying. The authors hypothesize that the cervical meningocele and the myelocystocele are part of a spectrum of the same underlying developmental abnormality, namely limited dorsal myeloschisis, with the eventual abnormality depending on the presence or absence of associated hydromyelia.

Myeloschisis is the most serious and complex congenital anomaly in spina bifida manifesta (cystica). However, with improvements in medical care and increased understanding of its pathophysiology, the associated long-term morbidity and mortality rates have been significantly reduced. This article reviews various issues associated with the neurosurgical management of patients with myeloschisis, such as perinatal management, repair surgery for myeloschisis, neurosurgical management of hydrocephalus, Chiari malformation type II, tethered cord syndrome and epilepsy, and intrauterine fetal surgery.

The usual location of human neural tube defects at the rostral or caudal end of the primary neural tube suggests they are caused by failure of closure of the neural tube. In this study, neural tube defects were created by surgical reopening of the neural tube of 3-day-old duck embryos in one of three sites: the forebrain, cervicothoracic region, or thoracolumbar region. It was determined that of the 31 survivors with forebrain incisions, 39% had exencephaly; of the 42 survivors with thoracolumbar incisions, 31% had myeloschisis; but of the 37 with a cervicothoracic incision, only 14% had exposed spinal cord. This indicates that a rostral-caudal distribution of neural tube defects can be seen in a model created by secondary reopening of the neural tube. ( J Child Neurol 1990;5:336-340).

We present findings obtained from a total of 100 patients who had previously undergone surgery for spina bifida and whose progress had been monitored by magnetic resonance imaging (MRI) in our meningomyelocele clinic. Fourteen of these patients (14.0%) developed delayed symptom(s) of progressive spinal neurologic dysfunction. In those with myeloschisis, increase of motor deficit was the most common clinical manifestation during infancy and early childhood (mean age: 6.8 years), whereas pain on back flexion was seen in patients who were over 15 years of age (mean age: 17.3 years). MRI carried out in myeloschisis patients invariably demonstrated that the conus medullaris was in an abnormally low position, suggesting over-distension of the spinal cord. This was irrespective of whether symptom(s) developed or not and did not correlate with the initial surgical procedure (reconstructive or otherwise) used. Patients with symptom(s) were revealed by MRI to have an extremely low conus set at the spinal level of S-1 or below; neurological examination showed that the motor deficit occurred at high levels in the spine. Results from lipomeningocele patients were more erratic in terms of conus position and delayed development of neurological defects. The authors conclude: (1) that elongation of the spinal cord as an MRI finding seen postoperatively in cases of myeloschisis (radiological finding of a low-placed concus medullaris) does not necessarily imply functional disorder (tethered cord syndrome) and (2) that the pathophysiology of the late onset of progressive neurological deterioration in the spine occurring in patients who have previously undergone lipomeningocele repair may be associated with an invasive or expansile mass effect and should not always be regarded as involving tethered cord syndrome.

To characterize the anatomical features of the ventricular regions in patients with myeloschisis and related to successful performance of endoscopic third ventriculostomy (ETV). Radiological and endoscopic findings of 21 myeloschisis patients were retrospectively reviewed. Radiological features that could interfere with endoscopic procedures were (1) a huge massa intermedia (12/19), (2) sloping of the third ventricular floor (3/10), (3) narrow anteroposterior length of the third ventricular floor (2/10), and (4) narrow prepontine cistern (8/21). Endoscopic findings were (a) a narrow foramen of Monro (0/3), (b) hypertrophy of the anterior commissure (1/3), (c) sloping of the third ventricle floor (1/3), (d) a huge massa intermedia (3/3), and (e) opaque third ventricular floor (3/3). These endoscopic findings did not interfere with endoscopic procedures by using the Oi-HandyPro neuroendoscope without the above-mentioned radiological features 3 or 4. Narrow anteroposterior length of the third ventricular floor and narrow prepontine cistern are not infrequently observed. Preoperative evaluation and intraoperative inspection of these findings are very important in successful performance of ETV.

Several groups have begun to explore the feasibility and utility of intrauterine closure of myelomeningocele. A subset of these fetuses have defects which fall into the category of myeloschisis, and therefore have inadequate skin to enable primary closure. After considerable discussion, it was decided to utilize bipedicular flaps to close these lesions. The procedure is described, and representative examples are shown. To date, 13 of 56 fetuses have required this approach for closure in utero. While this technique generally provides adequate coverage of the dural sac, the cosmetic results have been less than optimal.