Neurosurgical management of occult spinal dysraphism associated with OEIS complex

Retained medullary cord and caudal lipoma with histopathological presence of terminal myelocystocele in the epidural stalk

Background

The retained medullary cord (RMC), caudal lipoma, and terminal myelocystocele (TMCC) are thought to originate from the failed regression spectrum during the secondary neurulation, and the central histopathological feature is the predominant presence of a central canal-like ependyma-lined lumen (CC-LELL) with surrounding neuroglial tissues (NGT), as a remnant of the medullary cord. However, reports on cases in which RMC, caudal lipoma, and TMCC coexist are very rare.

Case Description

We present two patients with cystic RMC with caudal lipoma and caudal lipoma with an RMC component, respectively, based on their clinical, neuroradiological, intraoperative, and histopathological findings. Although no typical morphological features of TMCC were noted on neuroimaging, histopathological examination revealed that a CC-LELL with NGT was present in the extraspinal stalk, extending from the skin lesion to the intraspinal tethering tract.

Conclusion

This histopathological finding indicates the presence of TMCC that could not be completely regressed and further supports the idea that these pathologies can be considered consequences of a continuum of regression failure during secondary neurulation.

Surgical management of myelocystocele: a single-center experience with long-term functional outcomes

OBJECTIVE

Myelocystocele (MCC) is an uncommon form of skin-covered spinal dysraphism. The authors aimed to present long-term functional outcomes of patients treated for MCC with and without associated abnormalities of cloacal development (ACD).

METHODS

All patients with MCC and at least one tethered cord release (TCR) treated at a single institution between 1982 and 2019 were retrospectively reviewed. Demographic, operative, and functional outcome data were analyzed.

RESULTS

Of 51 children with MCC, 30 (58.8%) had MCC only and 21 (41.2%) had associated ACD (MCC/ACD). Thirty-two patients (62.7%) had undergone one TCR, while 19 patients (37.3%) had multiple TCRs. Urinary continence assessment was possible in 41 patients (80.4%), and bowel continence assessment was possible in 43 patients (84.3%) who were either older than 6 years or toilet trained. Although patients with MCC only were more likely to void volitionally (p = 0.0001), there was no difference in overall bladder continence based on the presence of ACD (p = 0.15) or the need for additional untethering procedures (p = 0.15). Those with MCC only were more likely to have overall bowel continence (p = 0.0001) and not require any management (p = 0.002), while those with MCC/ACD were more likely to have an ileostomy (p = 0.01). Of the 30 patients with MCC only, 29 (96.7%) were able to ambulate in the community. Of 21 patients with MCC/ACD, 14 (66.7%) were able to ambulate in the community, 5 (23.8%) were not ambulating, and 2 (9.5%) were therapeutic ambulators. A greater proportion of children in the MCC cohort were ambulating in the community (p = 0.01). There was no difference in community ambulation based on the number of TCRs (p > 0.99), but those with multiple TCRs were more likely to use braces (p = 0.01) and require lower-extremity orthopedic surgery (p = 0.01).

CONCLUSIONS

Patients born with an MCC, with or without an associated ACD, attained long-term favorable outcomes in bladder and bowel continence and ambulation.

Retained Medullary Cord Associated with Terminal Myelocystocele and Intramedullary Arachnoid Cyst

INTRODUCTION

The retained medullary cord (RMC) is a newly defined entity of closed spinal dysraphism that is thought to originate from regression failure of the medullary cord during the last phase of secondary neurulation. The terminal myelocystocele (TMC) is an unusual type of closed spinal dysraphism, characterized by localized cystic dilatation of the terminal part of the central canal that then herniates through a posterior spinal bifida. The co-occurrence of RMC and TMC is extremely rare.

CASE PRESENTATION

We treated a baby girl with a huge sacrococcygeal meningocele-like sac with two components. Untethering surgery and repair surgery for the sac revealed that RMC, associated with intramedullary arachnoid cyst (IMAC), was terminated at the bottom of the rostral cyst, forming the septum of the two cystic components, and the caudal cyst was TMC derived from the central canal-like ependymal lining lumen (CC-LELL) of the RMC at the septum. IMAC within the RMC communicated with TMC, and both contained xanthochromic fluid with the same properties.

CONCLUSION

We speculated that the mass effect of the coexistent IMAC impeded the flow of cerebrospinal fluid in the CC-LELL within the RMC and eventually formed a huge TMC. In surgical strategies for such complex pathologies, it is important to identify the electrophysiological border between the functional cord and nonfunctional RMC and the severe RMC to untether the cord, as with a typical or simple RMC.

Refractory CSF leakage following untethering surgery performed 10 months after birth for enlarging terminal myelocystocele associated with OEIS complex

Background:

Terminal myelocystocele (TMC) is an occult spinal dysraphism characterized by cystic dilatation of the terminal spinal cord in the shape of a trumpet (myelocystocele) filled with cerebrospinal fluid (CSF), which herniates into the extraspinal subcutaneous region. The extraspinal CSF-filled portion of the TMC, consisting of the myelocystocele and the surrounding subarachnoid space, may progressively enlarge, leading to neurological deterioration, and early untethering surgery is recommended.

Case Description:

We report a case of a patient with TMC associated with OEIS complex consisting of omphalocele (O), exstrophy of the cloaca (E), imperforate anus (I), and spinal deformity (S). The untethering surgery for TMC had to be deferred until 10 months after birth because of the delayed healing of the giant omphalocele and the respiration instability due to hypoplastic thorax and increased intra-abdominal pressure. The TMC, predominantly the surrounding subarachnoid space, enlarged during the waiting period, resulting in the expansion of the caudal part of the dural sac. Although untethering surgery for the TMC was uneventfully performed with conventional duraplasty, postoperative CSF leakage occurred, and it took three surgical interventions to repair it. External CSF drainage, reduction of the size of the caudal part of the dural sac and use of gluteus muscle flaps and collagen matrix worked together for the CSF leakage.

Conclusion:

Preoperative enlargement of the TMC, together with the surrounding subarachnoid space, can cause the refractory CSF leakage after untethering surgery because the expanded dural sac possibly increases its own tensile strength and impedes healing of the duraplasty. Early untethering surgery is recommended after recovery from the life-threatening conditions associated with OEIS complex.

Cutaneous Stigmata of the Spine: A Review of Indications for Imaging and Referral

Cutaneous stigmata of the midline spine are a common question in pediatrics. They are known to be related to a higher likelihood of underlying dysraphic spinal abnormalities. Clear understanding of different types of cutaneous stigmata and correlating dysraphic findings can aid in appropriate imaging workup and timely management of patient pathology. In this article, the authors review midline spinal cutaneous findings in the pediatric population with occult spinal dysraphism.

Enlargement of Extraspinal Cysts in Spinal Dysraphism : A Reason for Early Untethering

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.

Ependyma-Lined Canal with Surrounding Neuroglial Tissues in Lumbosacral Lipomatous Malformations: Relationship with Retained Medullary Cord

BACKGROUND

An ependyma-lined canal with surrounding neuroglial tissues can be present in lumbosacral lipomatous malformations; however, the precise embryological significance is still unclear.

METHOD

Six out of 50 patients with lipomatous malformations had ependymal structures. We retrospectively analyzed the clinical, neuroradiological, and histological findings of these patients to demonstrate the relationship with the embryological background of the retained medullary cord (RMC), which normally regresses, but was retained here because of late arrest of secondary neurulation.

RESULTS

Five (13.9%) of 36 patients with filar and caudal types and 1 of 3 lipomyelomeningoceles had ependymal structures, while none with dorsal and transitional types had these tissues. Histologically, the ependymal structures surrounded by neuroglial tissue and containing various amounts of adipose tissue bear a striking resemblance to the ependymal structures in RMC.

CONCLUSION

The 13.9% incidence of association between the ependymal structures and filar and caudal types is thought to be because of second ary neurulation failure with the same embryological background as that of RMC. Dorsal and transitional types, resulting from primary neurulation failure, therefore, did not have ependymal structures.

Usefulness of three-dimensional T1-weighted spoiled gradient-recalled echo and three-dimensional heavily T2-weighted images in preoperative evaluation of spinal dysraphism

PURPOSE

The aim of this study was to evaluate the usefulness of three-dimensional T1-weighted spoiled gradient-recalled echo (3D T1-GRE) images for the preoperative anatomical evaluation of lumbosacral lipoma, thick filum terminale, and myelomeningocele as a means of compensating for the drawbacks of 3D heavily T2-weighted (3D hT2-W) images.

METHODS

Nine patients with lumbosacral lipomas, one patient with tight filum terminale, and five patients with myelomeningoceles were included in this study. 3D T1-GRE images were compared with 3D hT2-W images or conventional magnetic resonance images in terms of delineation of lipomas and other structures in the patients with lipomas and tight filum terminale. For patients with myelomeningoceles, 3D T1-GRE images were compared with 3D hT2-W images in terms of artifacts in the cerebrospinal fluid (CSF) space.

RESULTS

The 3D T1-GRE images demonstrated lipomas with good contrast to the spinal cord and CSF space and more clearly delineated the anatomical relationship between lipomas and these structures than did the 3D hT2-W images. The 3D T1-GRE images delineated dural defects through which extradural lipomas penetrated into the intradural space. The 3D T1-GRE images also demonstrated the presence or absence of lipomas in the filum terminale and the absence of artifact in the myelomeningoceles. Furthermore, they were useful for differentiating artifacts observed on the 3D hT2-W images from nerve elements.

CONCLUSIONS

The complementary use of 3D T1-GRE and 3D hT2-W images may compensate for the drawbacks of 3D hT2-W images and may eventually improve lesion visualization and surgical decision making.

Complex forms of spinal dysraphism

INTRODUCTION

Spinal dysraphisms are a heterogeneous group of congenital malformations involving the bony component of vertebrae or spinal cord or both. Simple forms include the contiguous, solitary malformations such as myelomeningocele and diastematomyelia, and can be either aperta or occulta type.

MATERIAL

Complex forms include various types of spinal malformations occurring in combination, one type of malformations occurring at multiple levels in noncontiguous manner or spinal dysraphisms with other organ anomalies. Anomalous development in gastrulation, primary neurulation, and secondary neurulation stage in variable proportions give rise to these types of complex malformations. These cases can be diagnosed postnatally in early infancy by the strong clinical suspicion, supplemented by whole spinal axis and cranial magnetic resonance imaging (MRI) screening, to detect any occult spinal dysraphisms like split cord malformations, neurenteric cyst, lipoma, or cranial anomalies like Chiari malformations and hydrocephalus. Computed tomography and MRI are the gold standard to detect bony anomalies and cord malformations, respectively. Complex spinal dysraphisms, to our mind, should always be tried to be corrected in single operative stage, however, in case of ruptured defects, correction through multiple operations can be considered.

DISCUSSION

Overall, prognosis of complex forms of spinal dysraphism is poor in comparison to their simple forms and depends on preoperative neurological status and the nature of complex dyraphism. We discuss the classification, embryogenesis, investigation, and treatment protocol with review of literature of such complex anomalies.

Neurosurgical management of patients with lumbosacral myeloschisis

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.

Spinal cord malformations

Malformations of the spinal cord are one of the most frequent malformations. They should be clearly divided into two completely different families of malformations: open dysraphisms and occult dysraphisms. Open dysraphism mostly consists in myelomeningocele (MMC). Its incidence is 1/1000 live births with a wide variation. Folic acid supplementation has been shown to reduce its risk. In most cases, the diagnosis is done prenatally by serum screening and ultrasound and may lead to termination of pregnancy. In case of decision to continue pregnancy, surgical treatment must be achieved during the first days of life, and in 50 to 90% of cases, a ventricular shunt must be installed. The follow-up of these children must be continued throughout life looking for late complications (Chiari II and syringomyelia, vertebral problems, neuropathic bladder, tethered cord). Occult dysraphisms are a heterogeneous group of malformations. Lipomas (filum and conus) are the most frequent and their treatment remains controversial. Diastematomyelia, neurenteric cysts, dermal sinus, and more complex forms (Currarino syndrome) belong to this group. Most of them can and must be diagnosed prenatally or at birth by careful examination of the lower back for the cutaneous stigmata of the disease to decrease the risk of neurological, urological, or orthopedic permanent handicap.

Terminal myelocystocele: surgical observations and theory of embryogenesis

BACKGROUND

The structural complexity of terminal myelocystocele (TMC) precludes a recognizable link to spinal cord development and therefore a plausible embryogenetic theory.

OBJECTIVE

To demystify TMC using clinical, imaging, surgical, electrophysiological, and histopathological data and to propose a theory of embryogenesis.

METHODS

Our series consisted of 4 newborns and 6 older children. All had preoperative magnetic resonance imagings and surgical repair of the myelocystocele with electrophysiological monitoring.

RESULTS

TMC can be deconstructed into essential and nonessential features. Essential features are present in all TMCs and constitute the core malformation, comprising an elongated spinal cord extending extraspinally into a cerebrospinal fluid--filled cyst that is broadly adherent to the subcutaneous fat. The functional conus resides in the proximal cyst or within the intraspinal cord, and the caudal myelocystocele wall is nonfunctional fibroneural tissue. Nonessential features include variable measures of hydromyelia, caudal meningocele, and fat, present in only some patients. The core structure of TMC strikingly resembles a transitory stage of late secondary neurulation in chicks in which the cerebrospinal fluid-filled bleblike distal neural tube bulges dorsally to fuse with the surface ectoderm, before focal apoptosis detaches it from the surface and undertakes its final dissolution. We theorize that TMC results from a time-specific paralysis of apoptosis just before the dehiscence of the cystic distal cord from the future skin, thereby preserving the embryonic state.

CONCLUSION

Besides tethering, the myelocystocele may show early rapid expansion causing precipitous deterioration. We recommend early repair with resection of the nonfunctional caudal cyst wall, reconstruction of the proximal neural placode, and duraplasty.

Urgent surgery is needed when cyst enlarges in terminal myelocystoceles

PURPOSE

The phenomenon of cyst enlargement in terminal myelocystocele (TMC) patients has been mentioned in the literature. However, its clinical significance has not been clarified in depth. We reviewed TMC patients who had experienced cyst enlargement during the preoperative period to determine the correlation with symptomatic progression. We sought to determine the optimal surgical strategy for such patients.

METHODS

Of eight patients who were operated on for TMC from 1991 to 2009, four patients that showed cyst enlargement before the operation were reviewed. A retrospective review of medical recordings, radiological imaging, and other evaluations for neurologic status was done, focusing on the temporal neurological changes that correlated with the cyst enlargement.

RESULTS

Each of the four patients with cyst enlargement showed concurrent progression of neurologic symptoms, two by motor weakness and two by neurogenic bladder. In only one case, early detection and prompt surgery were possible, and this patient showed dramatic improvement in muscle strength after the surgery. The progression of neurologic deterioration was arrested postoperatively for the other three patients.

CONCLUSIONS

Hence, cyst enlargement in a TMC patient should be considered as a warning for neurologic deterioration, and the operation should be performed expediently to prevent impairment in neurologic function.

Prenatal diagnosis of OEIS (omphalocele, bladder exstrophy, imperforate anus, clubfeet) variant associated with increased nuchal translucency and OEIS complex with ambiguous genitalia associated with corrected transposition of the great arteries: case series and review of the literature

INTRODUCTION

The OEIS complex refers to a combination of defects consisting in omphalocele, bladder exstrophy, imperforate anus and spinal defects and represents a rare nosologic entity (from 1:200,000 to 1:400,000 pregnancies). The defect probably occurs in early blastogenesis or in mesodermal migration during the primitive streak period.

MATERIALS AND METHODS

Two cases of OEIS complex diagnosed prenatally by ultrasound are reported. The medical record regarding differential diagnosis, associated anomalies, treatment and prognosis has also been sought and reported.

CONCLUSION

Differential diagnosis with exstrophy-epispadias complex and/or cloacalexstrophy complex may be difficult antenatally by means of ultrasound. However, color Doppler has been proved to aid the diagnosis of bladder exstrophy by depicting the urine flow in direct communication with the abdominal cavity and has been useful in showing the course of the perivesical umbilical arteries. Prenatal 3D ultrasound with tomographic ultrasound imaging (TUI) and antenatal MR imaging might be useful adjuncts to conventional 2D scan in aiding the prenatal diagnosis of such malformation.

Detailed anatomy of intracranial venous anomalies associated with atretic parietal cephaloceles revealed by high-resolution 3D-CISS and high-field T2-weighted reversed MR images

PURPOSE

The advancement of magnetic resonance (MR) imaging technology has revealed that intracranial venous anomalies, such as vertical embryonic positioning of the straight sinus (VEP of SS), are associated with atretic parietal cephaloceles. However, the precise anatomical relationships among the venous anomalies, superior sagittal sinus (SSS), cistern, and cephalocele have not been demonstrated. We compared the imaging features of conventional MR images and high-resolution 3-dimensional (3-D) MR images, such as Fourier-transformation-constructive interference in steady-state (CISS) images and T2-weighted reversed (T2R) images obtained on a 3-T MR machine.

METHODS

Three patients ranging in age from 1 to 18 years, with midline subscalp lesions, participated in this study. In two cases, the lesions were surgically excised and subjected to pathological examination.

RESULTS

In two children, 3-D MR images more clearly demonstrated anomalous veins, including bilateral internal cerebral veins, the great vein of Galen and the vertical position of the straight sinus in the falx, extending superiorly within the CSF tract in the posterior interhemispheric fissure. While the vertical straight sinus drained into the SSS, the CSF tract maintained a position posterior to the anomalous veins, ran through the SSS and extended to the skull defect. In one patient, ascending positioning of the anomalous vein from the inferior sagittal sinus to the SSS in the CSF space was observed; this could not be depicted on conventional MR images.

CONCLUSION

Detailed findings of the venous anomalies on 3-D MR images provide clues to the diagnosis of atretic cephalocele.