Split Cord Malformations

Management of split cord malformation and tethered cord syndrome: Experience of a main referral center in Uzbekistan

BACKGROUND

Split cord malformation and tethered cord syndrome are challenging pathologies in the pediatric population. During 2016-2022, 56 cases of split cord malformation (SCM) and tethered cord syndrome were treated at the Republican Specialized Scientific Medical Practical Center of Neurosurgery (RSSMPCN) of Uzbekistan. This article aims to provide a retrospective analysis of the clinical presentation, radiological findings, and surgical outcomes of patients with split cord malformation and tethered cord syndrome.

METHODS

The retrospective study was conducted for 56 pediatric patients with split cord malformation and tethered cord syndrome during the abovementioned six-year period. All patients underwent MR imaging with computed tomography, followed by surgery with intraoperative neurophysiological monitoring. Each patient underwent follow-up examinations at 3 and 6 months postoperatively and yearly thereafter.

RESULTS

The mean patient age was 5.7 years (10 months to 15 years), and the male-to-female ratio was 1:2.2. Encouragingly, 44 (78.6 %) of the 56 patients showed improved neurological status postoperatively. Even in the cases where spur resection procedures were performed, there was partial neurological improvement, demonstrating the overall positive outcomes of the surgeries. Importantly, none of the 56 patients had neurological deteriorations in the postoperative period CONCLUSIONS: Split cord malformation is a rare but challenging pathology of childhood. The presentation is primarily characterized by movement, sensory or bowel disorders, and back and leg pain. This underscores the importance of early recognition and intervention when neurological symptoms are evident. Surgical intervention, as demonstrated in our study, is both appropriate and efficient in improving the neurological status of the patients.

Complex split cord malformation with split conus

Split cord malformations are disorders of gastrulation. Disorders of secondary neurulation occur later and are traditionally considered separate from the former. Complex split cord malformations involving both the cord and the conus and encompassing the epochs of gastrulation, primary neurulation, junctional neurulation, and secondary neurulation have not been described in literature. We present a four-year-old boy with such a malformation and postulate the embryological mechanism involved. The clinical vignette of this unique case has been described. We report a good clinical outcome in this patient with surgical management.

Classification of and individual treatment strategies for complex tethered cord syndrome

Objective

To study the classification, diagnosis, and treatment strategies of complex tethered cord syndrome (C-TCS) on the basis of the patients' clinical symptoms, imaging findings, and therapeutic schedule.

Methods

The clinical data of 126 patients with C-TCS admitted to our department from January 2015 to December 2020 were retrospectively analyzed. Classification criteria for C-TCS were established by analyzing the causes of C-TCS. Different surgical strategies were adopted for different types of C-TCS. The Kirollos grading, visual analogue scale (VAS), critical muscle strength, and Japanese Orthopaedic Association (JOA) scores were used to evaluate the surgical outcomes and explore individualized diagnosis and treatment strategies for C-TCS.

Results

C-TCS was usually attributable to three or more types of tether-causing factors. The disease mechanisms could be categorized as pathological thickening and lipomatosis of the filum terminal (filum terminal type), arachnoid adhesion (arachnoid type), spina bifida with lipomyelomeningocele/meningocele (cele type), spinal lipoma (lipoma type), spinal deformity (bone type), and diastomyelia malformation (diastomyelia type). Patients with different subtypes showed complex and varied symptoms and required individualized treatment strategies.

Conclusion

Since C-TCS is attributable to different tether-related factors, C-TCS classification can guide individualized surgical treatment strategies to ensure complete release of the tethered cord and reduce surgical complications.

Developmental Abnormalities of the Pediatric Spine: A Review of the Correlation Between Ultrasound and MRI Findings

A broad spectrum of spinal pathologies can affect the pediatric population. Ultrasound (US) is the primary modality for pediatric spine assessment due to its widespread availability, non-requirement of sedation, and absence of ionizing radiation. Supplementing this, MRI offers an in-depth exploration of these conditions, aiding in preoperative strategizing. In this review, we examine the clinical indications, methodologies, and protocols for US and MRI scans of the pediatric spine. Additionally, we illustrate normal pediatric spinal anatomy, highlighting several examples of normal variants that are often misinterpreted. Through a series of case-based illustrations, we offer a comprehensive overview of various pathological conditions such as tethered cord, spinal dysraphism, spinal lipoma, diastematomyelia, and dermal sinus tract, among others. Furthermore, we explore the correlation between US and MRI findings for these lesions, employing real-world cases to enhance our understanding of this topic.

Dekyphosis operation combined with limited osteotomy to treat the symptomatic adult tethered cord syndrome with complicated malformations: A case report

RATIONALE

Tethered cord syndrome (TCS) represents a spectrum of neurological symptoms that are caused by constant or intermittent axial traction of the terminal cone of the spinal cord due to abnormal positioning. It is uncommon for abnormal structures of TCS to be accompanied by split cord malformation, thoracic spinal stenosis, and other spinal cord diseases.

PATIENT CONCERNS

A 45-year-old male patient visited our hospital due to severe lower back pain, extensive left lower limb muscle weakness, and intermittent claudication.

DIAGNOSES

TCS combined with stenosis of the thoracic canal, split cord malformation, and kyphosis deformity.

INTERVENTIONS

The patient underwent Dekyphosis operation combined with limited osteotomy symptoms.

OUTCOMES

The patient felt the right lower limb improved after surgery. At 4-month follow-up, a radiological examination showed adequate decompression of the spinal cord and a good internal fixation position. Overall, the patient's clinical symptoms significantly improved.

CONCLUSION

This is a rare case of TCS combined with thoracic disc herniation and bony mediastinum. A more conservative invasive surgical approach was elected and markedly improved the patient's symptoms. Additional clinical cases are needed to confirm the stability and feasibility of this surgical approach.

Split Notochord Syndrome with Spinal Column Duplication and Spinal Cord Lipoma: A Case Report

Background and Importance: Split notochord syndrome (SNS) is an exceedingly rare type of spinal dysraphism. SNS is sometimes associated with other congenital dysraphic defects but, as in our case, the association with spinal cord lipoma, tethered cord, and spinal deformity in the form of spinal column duplication would be exceedingly rare. Herein, the authors report a three-year-old child presented with SNS associated with complex spinal deformity and other associated congenital anomalies. The patient underwent microsurgical release of the tethering element with excellent short- and long-term outcomes. Clinical Presentation: A male newborn with healthy nonconsanguineous parents was born with multiple gastrointestinal and genitourinary anomalies, and duplicated vertebral columns at the lumbosacral area consistent with split notochord syndrome. The patient was initially managed for the gastrointestinal and genitourinary anomalies. As there was no obvious neurological deficit initially, the neurosurgical intervention was postponed till the child reached 30 months of age, when he underwent uneventful release of both spinal cords at their spit point. Conclusions: SNS is an exceedingly rare developmental anomaly that is usually associated with varying degrees of complex congenital dysraphic defects. Early clinical diagnosis, understanding of the pathophysiology of spinal cord tethering, and microsurgical cord untethering are the important steps in optimal management.

Spine duplication or split notochord syndrome - case report and literature review

Context: Spine duplication is a rare condition, with various extents and severe additional anomalies. The goal of this study was to describe a unique case of a boy with split notochord syndrome who was followed up from birth until maturity. Findings: Physical examination at birth showed defects of the abdominal wall and cloacal exstrophy with visible urether outlets. A transposed anus was present in the perineal region. Split bony elements of the spine with nonpalpable sacral bone were noted. A soft, skin-covered lump, with the consistency of a lipoma, was present in the sacral area. There was asymmetry of the lower limbs: the left was hypoplastic, with a deformed foot and hip. Computed tomography revealed a normal shape of the Th12 and L1 vertebrae, whereas the L2 was split. Downward from L3, there were two vertebrae at each level, with two spinal canals. The spinal cord divided into two "semicords" at the level of L1. Neurologic status and the shape of the spine remained unchanged during puberty. The last follow-up was performed at the age of 18 years. He managed to walk independently in prosthesis with visible limping. Conclusion: Spine deformities are always suspected in neonates with lipoma in the sacral region, which may sometimes be serious. Walking ability and quality of life depend on neurologic deficits; even with long duplication and double sacrum, walking can be a feasible option.

Embryology of Spinal Dysraphism and its Relationship to Surgical Treatment

Spinal dysraphism is an umbrella term that encompasses a number of congenital malformations that affect the central nervous system. The etiology of these conditions can be traced back to a specific defect in embryological development, with the more disabling malformations occurring at an earlier gestational age. A thorough understanding of the relevant neuroembryology is imperative for clinicians to select the correct treatment and prevent complications associated with spinal dysraphism. This paper will review the neuroembryology associated with the various forms of spinal dysraphism and provide a clinical-pathological correlation for these congenital malformations.

Split spinal cord malformations in 4 Holstein Friesian calves

Background

The split spinal cord malformation (SSCM) is an uncommon congenital malformation of the vertebral canal in which parts of the spinal cord are longitudinally duplicated. In SSCM Type I, each spinal cord has its own dura tube. In the SSCM Type II, both parts of the spinal cord are surrounded by a common dura tube.

Cases presentation

During the clinical examination one calf showed ambulatory paresis and 3 calves non-ambulatory paraparesis. Calf 4 additionally had a congenital tremor. The examination of calf 4 using magnetic resonance imaging (MRI) showed a median hydrosyringomyelia at the level of the 4th lumbar vertebra. The caudal part of this liquid-filled cavity was split longitudinally through a thin septum. From there, the spinal cord structures duplicated with an incomplete division, so that the transverse section of the spinal cord appeared peanut-shaped and in each half a central canal could be observed. The pathological-anatomical examination after euthanasia showed a duplication of the spinal cord in the area of the lumbar vertebral column in all calves. The histopathological examination revealed two central lumbar vertebral column channels. The two spinal cord duplicates were each surrounded by two separate meninges in calf 2 (SSCM type I); in the other calves (1, 3, 4, and) the two central canals and the spinal cord were covered by a common meninx (SSCM type II). A pedigree analysis of calves 2, 3 and 4 showed a degree of relationship suggestive of a hereditary component. This supports the hypothesis of a possible recessive inheritance due to common ancestors, leading to partial genetic homozygosity.

Conclusions

The clinical appearance of SSCM can vary widely. In calves with congenital paralysis SSCM should always be considered as a differential diagnosis. A reliable diagnosis intra vitam is possible only with laborious imaging procedures such as MRI. Further studies on the heritability of this malformation are necessary to confirm a genetic cause of this disease.

Diagnosis and treatment of diastematomyelia in children: a perspective cohort study

Study design

Cohort study.

Objectives

The objectives of this study were examination, observation and surgical interventions of pediatric patients with diastematomyelia, a rare congenital deformity of the spinal cord.

Setting

Spine surgery and neurosurgery clinic under ministry of health, the Russian Federation.

Methods

Twenty children (1-18 years of age) with diastematomyelia participated in this study. Diagnosis was based on subjects' medical history, results of clinical examination, spine radiography in anteroposterior and lateral views, and neurophysiological examinations. Septum resection surgery was done in seventeen subjects.

Results

All the subjects had skin manifestations along the midline of the back. Neurological symptoms were noted in 17 subjects: paraparesis in 11, urinary incontinence in 2, monoparesis in 4, and spasticity in 2 subjects. Three subjects did not show any neurological deficit. Orthopedic examination revealed spinal deformities of various degrees of severity. In 4 subjects, partial restorations of neurological functions were observed; and in 1 subject, bladder incontinence developed after the surgery.

Conclusions

Patients who have limb length discrepancy, congenital scoliosis, skin manifestations should be examined for the presence of diastematomyelia. Patients having neither neurological deficit nor orthopedic deterioration should be monitored, and in case of deterioration, surgical treatment should be reserved. We advocate for performing resection of the septum in patients with diastematomyelia prior to surgical correction of scoliosis or orthopedic correction of lower limb deformities.

Lumbar spine duplication: a case report

Duplication of the spine is a rare malformation. A neurologically intact pediatric patient with this malformation is described here. A 6-year-old girl presented to our institution for evaluation of an asymptomatic kyphotic deformity. She denied weakness, sensory changes, and bowel or bladder complaints. Physical examination revealed mild kyphosis at the thoracolumbar junction with normal gait and neurologic function. Radiographs demonstrated duplication of the lumbar spine and sacrum. Computed tomography, MRI, and abdominal ultrasound results are reported. As she is neurologically normal, we will continue to observe this patient and intervene in the case of development of neurologic impairment or worsening kyphosis.

Split cord malformation combined with tethered cord syndrome in an adult

Split cord malformations (SCMs) usually present in childhood, and are rarely reported in adults. And also, a cervicothoracic SCM associated with tethered cord syndrome has very rarely been reported in the literature. We report a case of SCM associated with tethered cord and spina bifida in an adult. This report describes the case of a 34-year-old woman who presented for evaluation of neck pain, back pain, and intermittent paraparesis of several months duration. The MRI and CT showed a SCM at the cervicothoracic level and a fibrous septum at the thoracic level. She underwent surgery for the SCM and tethered cord syndrome, and was followed for 7 years. Patient presented complete recovery in the follow-up. The authors discuss this unusual lesion and describe the anatomical relationship of the level of cord duplication and fibrous septum.

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.

Long-segment type 1 split cord malformation with two-level split cord malformation and a single dural sac at the lower split

OBJECTIVE AND IMPORTANCE

Two-level bony spurs are rare and also a very long segment of bony spur is very rare. Bony spur with a single dural covering is not reported in the literature. Here, we report a case of prophylactic surgery performed on a patient with a bony spur with a single dural covering who showed a good postoperative outcome. This case highlights the importance of prophylactic surgery in such patients to avoid cord injuries.

CLINICAL PRESENTATION

Since birth a 1-year-old child had had a tuft of hair at the dorsal (D6 and D7) region. The patient was examined and found to have scoliosis with convexity towards the right. There was no neurological deficit. MRI and CT spine scans showed 2-level type 1 split cord malformation (SCM) and there was a low-lying conus at the L(3-4) level.

INTERVENTION

The patient was operated on at the age of 1 year and 2 separate bony septae were observed. The upper one extended from D5 to D9 and the lower one was at the D11 level. The bony spurs were excised. The filum was sectioned at the L(4-5) level by a separate incision. The patient had a good postoperative recovery.

CONCLUSION

With meticulous planning and careful surgery, prophylactic surgery can have a very good outcome in long-segment and two-level type 1 SCM.

Acquired Chiari I malformation in a child with corrected diastematomyelia disappeared after thickened filum division

INTRODUCTION

In recent years there has been renewed interest in the relation between Chiari I malformation and spinal cord tethering.

CASE REPORT

A 3-year-old girl presented with right leg pain. At spinal MR scan there was diastematomyelia with a bony peg at L1 and syringomyelia at T10-11. She had a surgical repair of the diastematomyelia without filum division. Symptoms settled postoperatively. A few months later she started displaying weakness in the right leg and loss of bulkiness of the right calf. A new MR scan showed a new Chiari I malformation, which was not present in the preoperative MR scan. The syringomyelia cavity was smaller. There was low-ending conus medullaris at L3 and a thickened filum. The filum was divided 15 months after the first operation. At MR scan obtained 18 months after filum division, the previously noted acquired Chiari I malformation had disappeared.

DISCUSSION

There is no obvious explanation for the formation of acquired Chiari I malformation and its disappearance after filum division. Recently, there has been description of patients with Chiari I malformation and normal posterior fossa volume, who were treated with filum division, and their Chiari malformation regressed without craniovertebral decompression surgery. Nevertheless, it is difficult to explain how traction on the lowest aspect of the spinal cord could lead to herniation of the cerebellar tonsils through the foramen magnum.

Spinal congenital dermal sinus with dual ostia

OBJECT

Congenital dermal sinus (CDS) usually develops in the midline of the body as a single tract. To date, only a few patients with multiple CDS tracts and ostia have been reported. The authors analyzed the clinical features of patients with spinal CDS and multiple ostia and proposed a novel hypothesis for the pathogenesis of the atypical CDS.

METHODS

Five patients with spinal CDS and multiple ostia were included. The clinical, radiological, and operative features of these patients were reviewed retrospectively.

RESULTS

Three patients demonstrated bilateral paramedian ostia at the same or a very similar spinal level. One patient showed a paramedian and a midline ostium. One patient had 2 unilateral paramedian ostia at different spinal levels. The layers of the internal ending of CDS tracts were diverse. Complete removal of the tracts was possible in all patients. Two patients had dermoid tumors. All patients had an associated anomaly, such as a lumbosacral lipoma or the Currarino triad. The authors propose a "zipping error" hypothesis for the formation of dual ostia located at the spinal level of primary neurulation. An associated anomaly such as a lumbosacral lipoma may contribute to the formation of dual ostia.

CONCLUSIONS

Unilateral or bilateral dual ostia may be present in patients with CDS, especially when an associated anomaly is present. The atypical CDS may develop from aberrant neural tube closure.

Diastematomyelia in children: treatment outcome and natural history of associated syringomyelia

OBJECTIVE

To quantify the long-term outcome of children with diastematomyelia and the implication of syringomyelia in the natural history.

MATERIALS

Retrospective study of 17 children (nine girls and eight boys) with diastematomyelia operated during 1989-2004. Mean age at diagnosis was 3.4 years (range 5 days-12 years), mean follow-up was 5 years; 14 had excision of spur and cord untethering, 3 had excision of spur alone.

RESULTS

The bony spur was in the lumbar region in 12 and thoracic in 5 patients. Syringomyelia was present in eight (47%), associated with bony spur between L1 and 4 (p=0.088), spina bifida occulta in ten (58.8%), and spinal lipoma in one (6%). Preoperative Necker Enfants Malades (NEM) scores were 17 in eight patients, 16 in four, 15 in three, 13 in one, and 12 in one patient. Presenting neurological deficits were motor in eight, sensory deficits in three, and anal incontinence in one patient. There was improvement of NEM scores postoperatively in five patients only, but still with residual deficit. Repeat spur excision and cord untethering was performed in three patients for neurological deterioration 1-4 years after first operation. On postoperative MRI scans syringomyelia remained unchanged in all eight patients. There were one skin infection, one transient motor deterioration, and one patient with sensory deficit after surgery.

CONCLUSION

Prophylactic operations were associated with the best clinical outcome. Despite improvement, all patients with established preoperative deficit still had residual neurological deficits at their last follow-up. The associated syringomyelia remained unchanged after surgery, indicating that it does not contribute to the neurological syndrome.

Part 3: examination of the newborn with closed spinal dysraphism

Spinal dysraphism, an incomplete closure of the neural tube, can be open, exposing the neural elements to the environment, or can be closed, covered with skin. Abnormal development of the spine occurs early in life and also interferes with usual development of the skin. This often creates cutaneous markers or stigmata over the area. Cutaneous markers may include a subcutaneous mass, abnormal hair growth, skin dimple, tag or sinus, or unusual pigmentation. Recognizing these markers is important because, although many closed spinal dysraphisms are asymptomatic at birth, neurological sequelae can occur. The sequelae are insidious and often permanent. This article, Part 3 in a series of articles devoted to spinal assessment, reviews closed spinal dysraphisms. The article emphasizes identification of various cutaneous markers associated with closed spinal dysraphisms. Early detection and follow-up may prevent neurologic sequelae for the infant later in life.

Congenital Anomalies of the Spine

The complexity of the congenital anomalies of the spine can make the neuroradiologic diagnosis challenging. Knowledge of spinal embryology greatly helps in the understanding and classification of these anomalies. We use the classification devised by Tortori-Donati and Rossi and find it helpful from clinical and imaging standpoints. We believe that most patients who have known or suspected congenital spinal anomalies benefit from MR imaging.

Double myelomeningocele in a neonate: Case report and review of the literature

The presence of myelomeningocele at multiple levels along the spinal column is extremely rare. There are only a few cases of double myelomeningocele reported in the literature. We report the case of a newborn male who had two myelomeningoceles with one at the cervical level and the other at the lumbar level. This unusual case report as well as a review of the literature is presented.

Examining the newborn with an open spinal dysraphism

Spinal dysraphism includes a constellation of frequent and potentially complex malformations of the spine and spinal cord. Open spinal dysraphisms, the majority of which are myelomeningoceles, have a number of associated morbidities that require both immediate and lifelong medical care. The role of the neonatal nurse includes the immediate stabilization of the affected infant, systematic examination of the malformation, and implementation of evidence-based protocols to ameliorate the associated medical problems. Coordination of care and communication and support of the family are essential aspects of care. This article reviews the embryology of open spinal dysraphisms and the steps needed to stabilize and evaluate affected infants.

Surgical technique and outcome in cervical and thoracic myelomeningocoele surgery

Cervical and thoracic myelomeningocoeles differ from common lumbosacral myelomeningocoeles in many respects. We review the surgical technique and outcome achieved for a series of six infants who underwent surgery for cervical or thoracic myelomeningocoele. Five patients, who had intradural exploration and microsurgical untethering of the spinal cord, were neurologically stable on follow-up. The other patient, who had a simple subcutaneous resection of the sac without release of the intradural tethering bands, was re-operated on 16 months later, with progressive neurological symptoms due to cord tethering. Following re-exploration and microsurgical untethering of the spinal cord, the neurological deficits significantly improved. We suggest that the surgical technique in these lesions should include careful intradural exploration and microsurgical release of the spinal cord by meticulous resection of all tethering bands. This enables postoperative neurological improvement and possible prevention of future neurological deficits due to cord tethering.

Split cord malformations: an experience of 203 cases

METHODS

A total of 203 patients with split cord malformation (SCM) were operated on at our centre between March 1989 and October 2003. Patients' demographic profile, radiological and operative details, complications and surgical outcome were evaluated retrospectively.

RESULTS

The mean age of the patients was 7.4 years and the female to male ratio was 1.3:1. The dorsolumbar and lumbar regions were the most common sites. One hundred thirty-two patients had type I SCM and 71 had type II SCM. One or more skin stigmata were present in 60% cases, hypertrichosis being the most common. Asymmetric weakness of the lower limbs and sphincter disturbances were present in 73 and 33% cases, respectively. Twenty-seven patients were asymptomatic. Of the symptomatic cases, 40.5% showed improvement in motor power, whereas 31% regained continence. The neurological status was unchanged in 48%. Seven percent of the patients showed neurological deterioration immediately after surgery.

CONCLUSIONS

SCMs are rare malformations of the spinal cord. We present the largest series so far reported in the world literature. The risk of developing neurological deficits increases with age; hence, all patients with SCM should be surgically treated prophylactically even if asymptomatic.

Split cord malformation with associated Type IV spinal cord perimedullary arteriovenous fistula

✓ The authors describe the case of a 62-year-old woman with a Type II split cord malformation (SCM). At the initial time of workup, the authors observed an associated Klippel—Feil deformity at the level of the SCM and a low-lying conus medullaris; however, they discovered an associated Type IV perimedullary spinal cord arteriovenous fistula (AVF) only after the patient continued to deteriorate following a spinal cord untethering procedure. Although prominent blood vessels have been reported within the median cleft of SCMs, an angiographically and surgically proven perimedullary AVF has not previously been described. The potential coexistence of SCM and perimedullary AVF has significant clinical implications and its recognition is critically important prior to surgical treatment.

Cervical meningocele in association with spinal abnormalities

CASE REPORT

This case report presents a newborn baby girl, who was diagnosed at birth with a mid-cervical meningocele. Further radiographic workup by MRI revealed co-existing thoracic diplomyelia and bilateral tethered cords. At birth the patient was found to be neurologically intact. Surgery was performed at 4 months of age, the patient undergoing simultaneous repair of the cervical meningocele, exploration of the diplomyelia, and release of the tethered cords bilaterally. Long-term follow-up revealed an ambulating patient with no bowel or bladder incontinence, who has developed well for her chronological age so far.

REVIEW OF THE LITERATURE

A review of the literature relevant to this case is also presented.

Embryology of myelomeningocele and anencephaly

The authors review current views on of the embryogenesis of the neural tube defects (NTDs) myelomeningocele and anencephaly. In this context, the following four approaches to the study of NTDs are discussed: normal morphogenesis and timing of early human neural development from conception to the ascent of the conus medullaris; mechanical and molecular biology of neural tube closure derived from experimental and animal models; morphological and biomechanical features of the NTDs myelomeningocele and anencephaly; and the experimental evidence for the importance of both genetic and environmental influences on human NTDs. Although considerable insight into both normal neural tube closure and the factor(s) by which this process may be disrupted has been reported in recent years, the exact mechanism(s) by which human myelomeningoceles and anencephaly arise remain elusive.

Thoracic diastematomyelia with concurrent intradural epidermoid spinal cord tumor and cervical syrinx in an adult

✓ Diastematomyelia is a rare entity in which some portion of the spinal cord is split into two by a midline septum. Most cases occur in childhood, but some develop in adulthood. A variety of concurrent spinal anomalies may be found in patients with diastematomyelia.

The authors describe a 38-year-old right-handed woman who presented with a 7-month history of lower-extremity pain and weakness on the right side. She denied recent trauma or illness. Sensorimotor deficits, hyperreflexia, and a positive Babinski reflex in the right lower extremity were demonstrated on examination.

Neuroimaging revealed diastematomyelia extending from T-1 to T-3, an expanded right hemicord from T-2 to T-4, and a C6–7 syrinx. The patient underwent T1–3 total laminectomies, resection of the septum, untethering of the cord, and excision of the hemicord lesion. The hemicord mass was determined to be an intramedullary epidermoid cyst; on microscopic evaluation the diastematomyelia cleft was shown to contain fibroadipose connective tissue with nerve twigs and ganglion cells. Postoperatively, the right lower-extremity pain, weakness, and sensory deficits improved.

Diastematomyelia can present after a long, relatively asymptomatic period and should be kept in the differential diagnosis for radiculopathy, myelopathy, tethered cord syndrome, or cauda equina syndrome. Numerous spinal lesions can be found in conjunction with diastematomyelia. To the authors' knowledge, this is the first case in which a thoracic epidermoid cyst and cervical syrinx occurred concurrently with an upper thoracic diastematomyelia. Thorough neuraxis radiographic evaluation and surgical treatment are usually indicated.

Split-cord malformation in a girl with Angelman syndrome: a mere coincidence?

We present a case of a girl with both Angelman syndrome and split-cord malformation. The child was initially referred at the age of 2.5 years, for developmental delay and a possible diagnosis of spina bifida occulta, based on the presence of a hair tuft located on the midline of the lumbar area. Magnetic resonance imaging of the spine showed split-cord malformation below L1, whereas a cytogenetically detected deletion of chromosome bands 15q11-q13 (SNRPN) confirmed the clinical diagnosis of Angelman syndrome. Split-cord malformation or diastematomyelia is a rare form of spina bifida occulta that occurs sporadically and is not particularly related to specific syndromes. Hair patches or other distinctive cutaneous stigmata such as those seen in the present case have not, to our knowledge, been reported in other patients with Angelman syndrome; therefore, the association of Angelman syndrome and split-cord malformation in this child is probably coincidental. Spinal cord abnormalities have not been consistently reported in patients with Angelman syndrome; only one adult patient with Angelman syndrome and spina bifida occulta has been reported, and this association was probably considered fortuitous. However, some relatively uncommon clinical features such as deterioration of gait, lower limb malformations, and bladder dysfunction, particularly as the patients age, although nonspecific, are reminiscent of such a cause. We therefore urge clinicians to look for cutaneous stigmata along the spine and consider the evaluation of the spinal cord in children with apparent paraparesis, out of proportion to that usually seen in Angelman syndrome, should our case report not just be a coincidental observation.

Undiagnosed adult diastematomyelia associated with neurological symptoms following spinal anaesthesia

Spinal anaesthesia is a safe, routinely performed procedure. However, in patients with lumbar cutaneous abnormities or deformities of the lower extremities, a previously undetected spinal anomaly may be present. In such patients, it may be prudent to avoid central neuraxial block to prevent neural damage. This instructive case presents such an adult patient in whom previously undiagnosed diastematomyelia, low conus and tethered cord was discovered only in the assessment of postspinal neurological symptoms.

Ventral tethering in split cord malformation

OBJECT

The author studied the specific issue of ventral tethering in cases of type II split cord malformation (SCM). He also discussed the issue of ventral tethering in patients with type I SCM in whom a bony septum and dural sleeve have been resected.

METHODS

Eleven (21%) of 52 patients with type II SCM were found to have a ventral fibrous septum tethering the hemicords to the ventral dura. Four categories of ventral septa were noted: 1) pure ventral intradural septa (three patients); 2) complete dorsoventral intradural septa (three patients); 3) dorsoventral septa continuous with a dermal sinus tract (two patients); and 4) ventral or complete septa continuous with ventral intestinal bands causing intestinal malrotation or diverticulum (three patients). Excluding one autopsy case, all 10 patients had symptoms or progressive neurological syndromes at diagnosis. Magnetic resonance imaging was completely ineffective, and computerized tomography (CT) myelography was only partially effective in detecting ventral tethering in 50% of cases. The only other positive predictor of ventral tethering is the association of dermal sinus tract and intestinal malformations. Combining this predictor with CT myelography, only 60% of the cases of ventral tethering could be suspected before surgery.

CONCLUSIONS

The author recommends examining all patients with type II SCM, and at surgery the ventral surface of the split length and reunion site should be thoroughly inspected to reveal a ventral band.