An atypical case of segmental spinal dysgenesis

Segmental spinal dysgenesis: insights from three consecutive cases and a review of the literature

OBJECTIVE

Segmental spinal dysgenesis (SSD) is a rare congenital spinal abnormality affecting the thoracic and lumbar region of the spine, as well as the spinal cord of neonates and infants. The purpose of the study was to analyze our institution's surgical case series to provide insights into our best practices to contribute to SSD management principles, while conducting a comprehensive literature review.

METHODS

Following institutional review board approval, a retrospective review of SSD surgical cases was examined to observe clinical findings, radiographic findings, management, surgical intervention, and outcomes. Keywords in the comprehensive literature review included SSD, congenital spinal dysgenesis, congenital spinal stenosis, spinal aplasia, and surgery.

RESULTS

Three cases underwent successful surgical management with either improvement or maintenance of neurological baseline. Patients were diagnosed at an average age of 2.7 months, while surgical intervention averaged at 40.3 months with fecal incontinence, neurogenic bladders, spinal cord compression, clubfoot, and concerns for worsening spinal deformity as surgical indicators. The average time for follow-up was 33.7 months and no complications were reported.

CONCLUSIONS

Operative management for SSD is a clinically complex decision that requires multidisciplinary input and care. Patients should be observed at neurological baseline and receive intervention at the appropriate time to allow sufficient growth for functioning without permitting drastic disease progression. Consideration of patient size and spinal instrumentation are significant towards surgical success.

Surgical treatment of segmental spinal dysgenesis: a report of 19 cases

STUDY DESIGN

Retrospective review.

OBJECTIVE

To describe clinical presentation, surgical management, long-term results, and complications in patients with segmental spinal dysgenesis (SSD). In addition, we sought to emphasize early surgery for this complex congenital abnormality. SSD is a rare congenital malformation characterized by focal stenosis, spinal subluxation, kyphosis, and absence of the nerve roots. Neurologic function ranges from normal to complete paraplegia. Progression of the deformity and neurologic deterioration is the rule.

METHODS

An independent spinal surgeon reviewed the complete records of 19 patients with SSD, between 1998 and 2015 at a single institution. Mean follow-up was 10 years and 6 months (2-14 years).

RESULTS

We evaluated 11 males and 8 females, with a mean age of 2 years and 9 months (5 months-15 years). The dysgenetic segment involved an average of 2.9 vertebrae (1-5); the upper thoracic region was most commonly involved in ten cases. Fifteen patients had severe spinal stenosis. 14 patients presented neurological deficits and 15 patients had associated organ and musculoskeletal anomalies.Twenty-seven surgeries were performed, a mean of 1.76 procedures (1-5) to obtain solid fusion. Neurologic function improved in four, deteriorated in three, and remained unchanged in 12 patients Seven complications were recorded.

CONCLUSION

We strongly recommend decompression and fusion as soon as possible to preserve or prevent neurologic deterioration. Although challenging, it was possible to achieve a solid instrumented fusion in all cases; however, a high rate of patients may deteriorate or not recover neurological status after surgery.

LEVEL OF EVIDENCE

Level IV evidence.

Do junctional neural tube defect and segmental spinal dysgenesis have the same pathoembryological background?

INTRODUCTION

Junctional neural tube defect (JNTD) is a recently introduced form of congenital spinal dysraphism that is characterized by functional disconnection between the primary and secondary neural tubes. The upper and lower cords appeared to be connected by a non-functioning band-like structure. JNTD is suspected to arise from a developmental error not corresponding to either primary or secondary neurulation, but rather between the two neurulation processes. On the other hand, segmental spinal dysgenesis (SSD) is an older entity of spinal anomalies in which a segment of the spine and spinal cord does not develop properly. The anomaly had been noted for the bony abnormality, as it is the most prominent feature. Based on the recent encounter of two cases resembling both entities, we sought the possibility that the two diseases may have the same pathoembryogenesis.

METHODS AND RESULTS

Based on the impression that the two entities share important features, we compared the details of the two anomalies. First, our two recently encountered cases of JNTD were described. Second, previous reports of SSD were comprehensively reviewed. The two cases had the essential anomaly of the neural structures satisfying the definition of JNTD, as well as the elaborate spinal deformity as seen in SSD. In the previous literature on SSD, it was recognized that in addition to the bone anomaly, disconnected spinal cord was present. Hence, the two entities seem to have many similar clinical and neuroimaging features. The dysgenic spinal level is similar, and the disconnection between the primary and secondary neural tubes is found in the two diseases. The two neural tubes are connected by a band-like structure, with severe stenosis of the spinal canal at the level of the band. Both entities show segmental anomalies of the vertebrae in the thoracolumbar region, especially in the posterior element. Although the extent of shared features seems high, the previously suggested hypothetical pathoembryogenesis of SSD did not involve the process of junctional neurulation. We suggest that SSD shares the same origin as JNTD, and the bony abnormality may be a secondary phenomenon to the core error during neural tube development.

CONCLUSIONS

We propose that JNTD and SSD may be the same entity, originating from an error during junctional neurulation. As there is controversy regarding the treatment strategy for both entities, unified accumulation of clinical experience and analysis may help improve the management of patients.

Segmental Spinal Dysgenesis-"Redefined"

STUDY DESIGN

Retrospective single institutional observational study.

PURPOSE

Segmental spinal dysgenesis (SSD), a complex spinal dysraphic state caused by notochord malformation disorders, is named after its morphological presentation where a spine segment is dysgenetic, malformed or absent. This study's objective was to examine and reassess SSD imaging findings and correlate them with an embryological explanation.

OVERVIEW OF LITERATURE

Scott and his colleagues defined SSD as segmental agenesis or dysgenesis of the lumbar or thoracolumbar vertebrae and underlying spinal cord. Tortori-Donati and his colleagues defined it as a morphologic continuum ranging from hypoplasia to an absent spinal cord segment.

METHODS

Fifteen children, whose imaging findings and clinical features were consistent with SSD, were included in the study. Magnetic resonance imaging (MRI) was performed per institutional spine protocol.

RESULTS

Five children (33.3%) presented with a high-ending bulbous cord with no caudal segment, six (40%) presented with a dorsal or lumbar segmental dysgenetic cord with a low-lying, bulky caudal cord but without significant spinal canal narrowing, and four (26.6%) presented with segmental caudal dysgenesis with severe kyphoscoliosis, gibbus deformity, and spinal canal narrowing with a normal distal segment (normal or low-lying).

CONCLUSIONS

SSD is a complex spinal anomaly in children requiring clinical-radiological assessment followed by multidisciplinary management based on the extent and severity of the dysgenetic cord and the type of SSD. MRI plays a crucial role in both diagnosing and classifying SSD prior to surgical treatment to prevent further impairment.

Imaging spectrum of spinal dysraphism on magnetic resonance: A pictorial review

Congenital malformations of spine and spinal cord are collectively termed as spinal dysraphism. It includes a heterogeneous group of anomalies which result from faulty closure of midline structures during development. Magnetic resonance imaging (MRI) is now considered the imaging modality of choice for diagnosing these conditions. The purpose of this article is to review the normal development of spinal cord and spine and reviewing the MRI features of spinal dysraphism. Although imaging of spinal dysraphism is complicated, a systematic approach and correlation between neuro-radiological, clinical and developmental data helps in making the correct diagnosis.

Segmental spinal dysgenesis: a report of early surgical intervention and outcome in a 14-month-old child

Segmental spinal dysgenesis is a rare spinal deformity that is the result of failure of formation resulting in some cases spondyloptosis and neurological dysfunction usually at the thoracolumbar junction. There is little known concerning surgical intervention and timing in these patients. The goal of this case report is to present a case involving 14 months old diagnosed with segmental spinal dysgenesis with stenosis at the thoracolumbar junction soon after birth, treated with definitive posterior spinal fusion and subsequent follow-up.