Patterns of congenital bony spinal deformity and associated neural anomalies on X-ray and magnetic resonance imaging

Spinal dysraphism in congenital scoliosis and kyphosis: a retrospective analysis in an Indian population

PURPOSE

Early recognition is crucial for occult spinal dysraphism associated with congenital spinal deformities. There is limited literature available on its occurrence in congenital scoliosis and kyphosis in the Indian population.

METHODS

Our study involved a retrospective review of 247 children who presented at a single centre. We analyzed their demographics and clinical and radiological findings, which included the type of deformity, its location, vertebral anomaly, Cobb angle, and MRI findings. The deformities were categorized as congenital scoliosis or congenital kyphosis with failure of formation, failure of segmentation, or both.

RESULTS

A total of 247 cases were examined (congenital scoliosis-229, congenital kyphosis-18). The average age was seven years (range 0.8 to 19 years, SD 4.6). The mean Cobb angle at presentation in the congenital scoliosis group was 49.4° (range 8 to 145°, SD 23.77) for those with abnormal MRI and 42.45° (range 5 to 97°, SD 20.09) for those with normal MRI. For the congenital kyphosis group, the mean K angle at presentation was 47.7° (range 14 to 110°, SD 33.33) for those with abnormal MRI and 47.36° (range 15 to 70°, SD 16.63) for those with normal MRI. Abnormal MRI results were observed in 130 of the patients (congenital scoliosis-53.7%, congenital kyphosis-38.8%). The highest incidence of abnormal MRI findings was observed in the failure of segmentation (66.6%) and mixed (65%) types. Deformities in the dorsal region had the highest incidence (61.9%). The most common dysraphism instances were diastematomyelia and tethered cord. There was a significant correlation between type of deformity and presence of dysraphism.

CONCLUSION

This is the largest case series of congenital scoliosis and kyphosis reported from India. We found a high incidence of occult spinal dysraphism as compared to other published series. Occult spinal dysraphism is more common in the thoracic region. Diastematomyelia followed by tethered cord was the most common anomaly observed. We recommend MRI screening of whole spine and craniovertebral junction.

Is Intervertebral Disc Degeneration a Compensatory Mechanism in Adult Tethered Cord Syndrome?

OBJECTIVE

The purpose of the present study was to evaluate the influence of high nerve tension on lumbar disc degeneration and sagittal morphologies.

MATERIALS AND METHODS

A total of 50 young and middle-aged patients (mean age 32.1 ± 7.4 years, 22 men and 28 women) who suffered from tethered cord syndrome (TCS) were retrospectively assessed by two observers. Demographic and radiological data were recorded, including lumbar disc degeneration, disc height index and lumbar spine angle, and were compared with 50 patients (mean age 29.7 ± 5.4 years, 22 men and 28 women) without spinal cord abnormalities. Statistical associations were assessed by student's t-test and chi-square test.

RESULTS

Our results showed patients with TCS had a significantly higher rate of lumbar disc degeneration in L1/2, L2/3, L4/5 and L5/S1 than in those without TCS (P < 0.05). Moreover, the rates of multilevel disc degeneration and severe disc degeneration in TCS group were significantly higher than those in control group (P < 0.01). The mean disc height index of L3/4 and L4/5 in TCS group was significantly lower than that in control group (P < 0.05). The mean lumbosacral angle of TCS patients was significantly higher than that of patients without TCS (38.4 ± 3.5°vs. 33.7 ± 5.9°, P < 0.01).

CONCLUSIONS

We found a certain correlation between TCS and lumbar disc degeneration and lumbosacral angle enlargement, suggesting that the spine reduces the high tension of the spinal cord through disc degeneration. Therefore, it is speculated that there is a "compromised regulation" mechanism in the body under the condition of neurological abnormalities.

Fetal MRI prior to intrauterine surgery of open neural tube defects: What does the radiologist need to know

The management of myelomeningocele study trial showed significant prognostic improvement in fetal repair before 26 weeks of gestation. Hence, surgery in utero represents the best treatment option for open-neural tube defects (NTDs). Fetal surgery of open-NTDs has specific inclusion and exclusion criteria, which can be adequately studied with fetal MRI. The main concern: the spine (spinal defects other than Myelomeningocele and Myeloschisis, the level of the lesion higher than T1 or lower than S1 and the degree of kyphosis ≥ 30°), the skull/brain (no cerebellum herniation and Chiari II malformation and the presence of any intracranial abnormality unrelated to open NTDs), the uterus (cervix length less than 2 cm, multiple gestations and placental and uterine abnormalities) and any other fetal abnormality not attributed to spinal defect. In this review, we describe the fundamental role of fetal MRI in supporting therapeutic decisions in pre-surgery intrauterine planning through the accurate and comprehensive description of findings, providing a proposal of a structured report. In addition, we describe how post-surgical MRI is important in investigating the effectiveness of surgery and detecting repairing complications.

Accelerated three-dimensional susceptibility weighted imaging of the whole spine of fetus at 3T

OBJECTIVES

To investigate the image quality and capability of generalized auto-calibrating partially parallel acquisition (GRAPPA) accelerated Three-dimensional (3D) susceptibility weighted imaging (SWI) of the whole spine at 3T.

METHODS

A total of 37 pregnant women (gestation age 22 to 39 weeks, average 29 ± 3 weeks) with suspected fetal vertebral anomalies by ultrasound (US) screening underwent 3.0T MR imaging with 3D SWI, conventional two-dimensional (2D) half-flourier acquisition single-shot turbo spin-echo (HASTE) and 3D true fast imaging with steady-state precession (True FISP). The acquisition time of each protocol was recorded. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were determined in representative interest regions of fetal thoracic vertebrae and compared among three pulse sequences. Two radiologists rated image quality independently in random order on a 5-point scale. Kappa coefficients were computed to assess inter-observer reliability. Receiver operating characteristic curves were generated, and the area under the curve (AUC) was used to compare the diagnostic performance of each protocol in vertebral deformities.

RESULTS

The acquisition time was 15 s for 3D-SWI and 17 s for 3D True FISP, significantly shorter than conventional HASTE (37 s; both P < 0.01). Of the three protocols, The SNR was highest on 3D True FISP, while the CNR was highest on 3D SWI. Visualization of all segments of the whole spine by 3D SWI was comparable with 3D True FISP. In contrast, 3D SWI and 3D True FISP depicted cervical and sacrococcygeal vertebrae better than HASTE. The weighted kappa statistic was 0.70-0.89 to evaluate the image quality of all segments of the whole spine, indicating good to excellent interobserver agreement. 3D SWI had the highest diagnostic performance for detecting fetal vertebral anomalies (AUC = 0.92).

CONCLUSIONS

3D-SWI is feasible for improved visualization of the whole fetal vertebral column and its congenital malformations with adequate image quality and high accuracy, thereby providing a supplementary method to conventional MR imaging.

The value of magnetic resonance imaging and computed tomography in the study of spinal disorders

Computed tomography (CT) and magnetic resonance imaging (MRI) have replaced conventional radiography in the study of many spinal conditions, it is essential to know when these techniques are indicated instead of or as complementary tests to radiography, which findings can be expected in different clinical settings, and their significance in the diagnosis of different spinal conditions. Proper use of CT and MRI in spinal disorders may facilitate diagnosis and management of spinal conditions. An adequate clinical approach, a good understanding of the pathological manifestations demonstrated by these imaging techniques and a comprehensive report based on a universally accepted nomenclature represent the indispensable tools to improve the diagnostic approach and the decision-making process in patients with spinal pain. Several guidelines are available to assist clinicians in ordering appropriate imaging techniques to achieve an accurate diagnosis and to ensure appropriate medical care that meets the efficacy and safety needs of patients. This article reviews the clinical indications of CT and MRI in different pathologic conditions affecting the spine, including congenital, traumatic, degenerative, inflammatory, infectious and tumor disorders, as well as their main imaging features. It is intended to be a pictorial guide to clinicians involved in the diagnosis and treatment of spinal disorders.

The role of radiography in the study of spinal disorders

Despite the growing use of computed tomography (CT) and magnetic resonance imaging (MRI) in the study of spinal disorders, radiography still plays an important role in many conditions affecting the spine. However, the study and interpretation of spine radiograph is receiving less attention and radiologists are increasingly unfamiliar with the typical findings in normal and pathologic conditions of the spine. The aim of this article is to review the radiologic indications of radiograph in different pathologic conditions that affect the spine, including congenital, traumatic, degenerative, inflammatory, infectious and tumour disorders, as well as their main radiographic manifestations.

Cervical Abnormalities in Severe Spinal Deformity: A 10-year MRI Review

Objective

To investigate the incidence of cervical anomalies (CA), including cervical intraspinal neural axis abnormalities (CIINAA) and/or cervical osseous abnormalities (COA), and the clinical relevance in severe spinal deformities (SSD) at a single center.

Methods

A retrospective study of SSD admitted for spinal surgery from January 2003 to January 2015 was conducted at a single center. Inclusion criteria: patients who present with coronal Cobb over 90° (and/or sagittal cobb ≥90°); and patients with complete imaging and clinical data preoperatively. Exclusion criteria: ankylosing spondylitis, adult onset scoliosis, scoliosis secondary to bone destruction. There were 108 SSD patients who fulfilled the criteria in this research (41 males and 67 females). The mean age of the patients was 18.1 ± 2.7 years (range, 10–45 years). The clinical and radiological data of these patients were reviewed to identify CA and to analyze the relationship between clinical and radiographic characteristics in the population of SSD.

Results

The major curves of scoliosis and segmental kyphosis were 109.1° ± 24.7° and 91.2° ± 29.1°. Cervical abnormalities were detected in 56 patients (51.85%) with 9 different CA, including 28 patients (25.9%) with 6 different COA, 21 patients (19.4%) with 3 different CIINAA, and 7 patients (6.5%) with a combination of COA and cervical intraspinal neural axis abnormalities (CINAA). Basilar invagination and Klippel–Feil syndrome were the most frequent COA. Syringomyelia was the most frequent CINAA. SSD with COA in upper vertebral levels (UVL) had a higher incidence of CINAA than those in subaxial vertebral levels (SVL) (P = 0.024) and SSD with multiple COA (mCOA) in UVL had a higher incidence of CINAA than those with single COA (sCOA) (P = 0.029). In the present study, 83.9% of the SSD with CA were asymptomatic.

Conclusion

The incidence of CA in SSD was 51.85%, with most presenting with intact neurologic status. As the diversity of COA increased, we found a higher incidence of CINAA, especially in UVL.

Structured MRI reporting in spinal dysraphism

Magnetic resonance evaluation of spinal dysraphism can be confusing for inexperienced radiologists and a detailed, step-by-step evaluation of the normal and abnormal imaging findings can help garner the diagnosis. The purpose of this article is to review the existing literature and to provide a comprehensive, structured, template checklist-style format for reporting spinal dysraphism that can help inexperienced radiologists to systematically analyze and report all the significant and ancillary findings in cases of spinal dysraphism and efficiently communicate the findings to the treating physician/surgeon.

Frequency and characteristics of congenital intraspinal abnormalities in a cohort of 128 patients with congenital scoliosis

OBJECTIVES

The aims of this study were to determine the incidence and main characteristics of associated intraspinal anomalies in patients with congenital scoliosis (CS) and to analyze the different factors that influence the curve progression.

DESIGN

This was a retrospective comparative study.

METHODS

This was a retrospective study of 128 patients with CS.

MAIN OUTCOME MEASUREMENTS

The incidence of the patients with intraspinal anomalies and their demographic, clinical, and radiological values was described.

RESULTS

Intraspinal anomalies were present in 13.3% of the patients. Among them, the most frequent anomaly was syringomyelia. The most frequent curve was the thoracic curve. The main deformity based on McMaster classification was formation failure. The curve progression during follow-up did not show significant differences between vertebral anomalies, syringomyelia, presence of thoracic anomalies, and gender (P > 0.05).

CONCLUSIONS

Our study showed a lower percentage of spinal anomalies compared to other series. As other studies, the progression of the scoliosis curve in patients with spinal anomalies seems primarily to be determined by the type of vertebral malformation.

LEVEL OF EVIDENCE

Level II.

Tethered cord syndrome and transitional vertebrae

PURPOSE

Tethered cord syndrome (TCS) usually presents with low-lying conus medullaris and thickened filum terminale. Spinal cord anomalies usually accompany congenital malformations and variations of the vertebral column. Transitional vertebrae (TV) are common variant, especially in the lumbosacral region. Accurate definition of the spine level is essential for proper radiological diagnosis and treatment. In this study, congenital spinal cord and vertebral anomalies and the relation with TV groups and types were evaluated in TCS patients.

METHODS

The study was performed in 97 patients. Radiological imaging findings [computed tomography (CT), magnetic resonance imaging (MRI), and radiography] and medical records were evaluated. Spine bony malformation, spinal cord malformation, and spinal level of malformation were compared with TV and non-TV groups in TCS patients. In addition, TV groups and types were compared with each other for these anomalies.

RESULTS

There was no statistically significant difference between TV and non-TV group in terms of the presence of vertebral bone and spinal cord anomalies. There were some significant differences in some of the spine bone and spinal cord anomalies among the groups and types of TV.

CONCLUSION

Sixty-two point nine percent TCS patients had TV. Although these findings indicate that TV is common in patients with TCS, no significant difference is observed in most of the studied anomalies. However, there were some differences among the TV groups and TV types in relation to congenital malformations. It can be concluded that TV anomaly could be a distinct malformation apart from all the other anomalies that were studied. Transitional vertebrae may cause pain due to biomechanical changes in addition to progressive neurological symptoms which are usually seen with TCS.

Normal development of the fetal spinal canal and spinal cord at T12 on 3.0-T MRI

BACKGROUND

The studies that described the dimensions of the normal fetal thoracic spinal canal and spinal cord on magnetic resonance imaging (MRI) are scarce.

PURPOSE

To determine the normal appearance of the fetal spinal canal and spinal cord at T12 across different gestational ages using 3.0-T MRI.

MATERIAL AND METHODS

The spines of 43 normal human fetuses, aged 15-40 weeks, were scanned by 3.0-T MRI. All specimens were scanned using a GE 3.0-T MRI scanner. Imaging of the T12 vertebrae was performed in the coronal, sagittal, and axial planes. The anterior-posterior (AP) diameter, width, and cross-sectional area of the spinal canal and spinal cord at T12 were measured. The influence of gestational age on these parameters was investigated with a scatter plot and linear regression analysis using Pearson correlation coefficient.

RESULTS

The normal morphology of the fetal vertebra at T12 can be clearly showed by MRI; the spinal canal appeared circular, while the spinal cord was ellipsoid. Linear regression analysis showed a significant positive correlation between the AP diameter, width, and cross-sectional area of the spinal canal at T12 and gestational age.

CONCLUSION

Postmortem MRI is a reliable method for understanding the growth dynamics of the spinal canal and spinal cord at T12. Findings from this study would benefit the prenatal diagnosis of congenital malformations by MRI.

Malformed vertebrae: a clinical and imaging review

A variety of structural developmental anomalies affect the vertebral column. Malformed vertebrae can arise secondary to errors of vertebral formation, fusion and/or segmentation and developmental variation. Malformations can be simple with little or no clinical consequence, or complex with serious structural and neurologic implications. These anomalies can occasionally mimic acute trauma (bipartite atlas versus Jefferson fracture, butterfly vertebra versus burst fracture), or predispose the affected individual to myelopathy. Accurate imaging interpretation of vertebral malformations requires knowledge of ageappropriate normal, variant and abnormal vertebral morphology and the clinical implications of each entity. This knowledge will improve diagnostic confidence in acute situations and confounding clinical scenarios.

This review article seeks to familiarize the reader with the embryology, normal and variant anatomy of the vertebral column and the imaging appearance and clinical impact of the spectrum of vertebral malformations arising as a consequence of disordered embryological development.

Teaching points

• Some vertebral malformations predispose the affected individual to trauma or myelopathy.

• On imaging, malformed vertebrae can be indistinguishable from acute trauma.

• Abnormalities in spinal cord development may be associated and must be searched for.

• Accurate interpretation requires knowledge of normal, variant and abnormal vertebral morphology.

Imaging in the Diagnosis and Monitoring of Children with Idiopathic Scoliosis

The paper reviews the current imaging methods in the diagnosis and monitoring of patients with adolescent idiopathic scoliosis. Radiography is generally used in the initial diagnosis of the condition. Postero-anterior erect full spine radiograph is generally prescribed, and is supplemented by lateral full spine radiograph when indicated. To reduce the radiation hazard, only the area of interest should be exposed, and follow-up radiographs should be taken with as few projections as possible. When available, EOS® stereoradiography should be used. The radiation of the microdose protocol is 45 times less than that of the conventional radiography. Surface topography offers another approach to monitoring changes of curvatures in AIS patients. Recently, 3D ultrasound has been found to be able to measure the Cobb angle accurately. Yet, it is still in the early developmental stages. The inherent intrinsic and external limitations of the imaging system need to be resolved before it can be widely used clinically. For AIS patients with atypical presentation, computed tomography (CT) and/or magnetic resonance imaging (MRI) may be required to assess for any underlying pathology. As CT is associated with a high radiation dose, it is playing a diminishing role in the management of scoliosis, and is replaced by MRI, which is also used for pre-operative planning of scoliosis. The different imaging methods have their limitations. The EOS® stereoradiography is expensive and is not commonly available. The surface topography does not enable measurement of Cobb angle, particularly when the patient is in-brace. The 3D ultrasound scanning has inherent intrinsic technical limitation and cannot be used in all subjects. Radiography, however, enables diagnosis and monitoring of the adolescent idiopathic scoliosis (AIS). It is thus the gold standard in the evaluation and management of scoliosis curves.