Congenital spine deformities: scoliosis, kyphosis, and lordosis

Feasibility analysis of intrathecal administration strategy of nusinersen based on Cobb angle in children with spinal muscular atrophy

AIM

This retro-prospective observational study described the experience in lumbar puncture procedures in children with spinal muscular atrophy (SMA) with and without neuromuscular scoliosis in a single center. The technical feasibility of intrathecal nusinersen administration was the main limiting factor.

STUDY DESIGN

A total of 457 technically successful intrathecal injections based on a hierarchical strategy in Cobb angle were reviewed in 81 SMA children aged 0.75-13.5 years who were referred for nusinersen injections in our hospital from October 2019 to December 2022.

RESULTS

Under local anesthesia, conventional lumbar puncture was performed on 47 patients without spinal deformity (Cobb angle of 0-10°) and 20 patients with moderate scoliosis (Cobb angle of 10-50°). Ultrasound-assisted lumbar puncture was performed on 12 patients with moderate scoliosis but lordosis. A combination of ultrasound imaging and three-dimensional CT under sedation was performed in the remaining 14 patients with severe scoliosis (Cobb angle >50°). No severe complications were found.

CONCLUSION

Cobb angle is an important basis for intrathecal administration of nusinersen. It is feasible and suitable to carry out intrathecal nusinersen injection under ultrasound combined with three-dimensional CT imaging for children with severe scoliosis.

Building a Co-ordinated Musculoskeletal System: The Plasticity of the Developing Skeleton in Response to Muscle Contractions

The skeletal musculature and the cartilage, bone and other connective tissues of the skeleton are intimately co-ordinated. The shape, size and structure of each bone in the body is sculpted through dynamic physical stimuli generated by muscle contraction, from early development, with onset of the first embryo movements, and through repair and remodelling in later life. The importance of muscle movement during development is shown by congenital abnormalities where infants that experience reduced movement in the uterus present a sequence of skeletal issues including temporary brittle bones and joint dysplasia. A variety of animal models, utilising different immobilisation scenarios, have demonstrated the precise timing and events that are dependent on mechanical stimulation from movement. This chapter lays out the evidence for skeletal system dependence on muscle movement, gleaned largely from mouse and chick immobilised embryos, showing the many aspects of skeletal development affected. Effects are seen in joint development, ossification, the size and shape of skeletal rudiments and tendons, including compromised mechanical function. The enormous plasticity of the skeletal system in response to muscle contraction is a key factor in building a responsive, functional system. Insights from this work have implications for our understanding of morphological evolution, particularly the challenging concept of emergence of new structures. It is also providing insight for the potential of physical therapy for infants suffering the effects of reduced uterine movement and is enhancing our understanding of the cellular and molecular mechanisms involved in skeletal tissue differentiation, with potential for informing regenerative therapies.

Turning the Curve Into Straight: Phenogenetics of the Spine Morphology and Coordinate Maintenance in the Zebrafish

The vertebral column, or spine, provides mechanical support and determines body axis posture and motion. The most common malformation altering spine morphology and function is adolescent idiopathic scoliosis (AIS), a three-dimensional spinal deformity that affects approximately 4% of the population worldwide. Due to AIS genetic heterogenicity and the lack of suitable animal models for its study, the etiology of this condition remains unclear, thus limiting treatment options. We here review current advances in zebrafish phenogenetics concerning AIS-like models and highlight the recently discovered biological processes leading to spine malformations. First, we focus on gene functions and phenotypes controlling critical aspects of postembryonic aspects that prime in spine architecture development and straightening. Second, we summarize how primary cilia assembly and biomechanical stimulus transduction, cerebrospinal fluid components and flow driven by motile cilia have been implicated in the pathogenesis of AIS-like phenotypes. Third, we highlight the inflammatory responses associated with scoliosis. We finally discuss recent innovations and methodologies for morphometrically characterize and analyze the zebrafish spine. Ongoing phenotyping projects are expected to identify novel and unprecedented postembryonic gene functions controlling spine morphology and mutant models of AIS. Importantly, imaging and gene editing technologies are allowing deep phenotyping studies in the zebrafish, opening new experimental paradigms in the morphometric and three-dimensional assessment of spinal malformations. In the future, fully elucidating the phenogenetic underpinnings of AIS etiology in zebrafish and humans will undoubtedly lead to innovative pharmacological treatments against spinal deformities.

Effectiveness of Kyphosis Reduction Using Cantilever Method in Thoracolumbar Spondylitis Tuberculosis: A Short-Term Follow-Up

Background

Kyphosis in spondylitis tuberculosis (STb) is more than just a cosmetic issue. It has a potentially detrimental effect on both spine-associated structures and cardiopulmonary function. It can be corrected in any stage of STb; however, the corrective surgery is challenging, especially in the late case, in which the additional stiffness of the spine can come into consideration. To date, the cantilever technique is still a gold standard for sagittal plane deformity correction. However, no study to date has explored its effectiveness for thoracolumbar kyphotic deformity, especially that caused by spondylitis tuberculosis.

Methods

This is a retrospective study of 16 consecutive cases of spondylitis tuberculosis with thoracolumbar kyphosis that underwent corrective surgery in our center in the period of 2020–2021. We aim to evaluate the effectiveness of the cantilever technique that we use for kyphotic correction in thoracolumbar STb patients.

Results

At the 3-months follow-up, the mean Cobb angle was 14.6°±10.27°, with the mean gain of 20.90°±12.00° and positively correlate with the thoracolumbar kyphosis (TLK) correction (68.69%, r = 0.654, p = 0.001). The mean thoracic kyphosis, lumbar lordosis, and sagittal vertebral axis were 30.6°±13.08°, 39.4°±16.02°, and 1.4±4.09 cm, respectively, with sagittal Cobb difference of 12.70±9.85.

Conclusion

The kyphotic Cobb angle reduction by cantilever technique in the thoracolumbar area significantly improved the thoracolumbar kyphosis and realign the spinal sagittal axis. Thus, the cantilever technique remains the gold standard for sagittal plane deformity correction which can be applied for kyphotic deformity correction in thoracolumbar STb cases.

Cantilever method for severe kyphotic deformity correction in spondylitis tuberculosis: A technical note and literature review

Background

The kyphotic deformity is more than just a cosmetic disfigurement. It is potentially life-threatening and disturbs the quality of life by causing cardiopulmonary dysfunction, spinal imbalance, and other associated problems. Corrective surgery is challenging but it is needed to bring the spinal balance back thus halting the progressiveness of the deformity. The cantilever technique is a gold standard to correct the sagittal plane deformity.

Methods

This is a review article with some case illustrations from Author's experience.

Objective

We aim to review the cantilever technique for kyphotic correction in spondylitis tuberculosis patients.

Conclusion

The cantilever technique is the standard for sagittal plane deformity correction that can be applied for kyphotic deformity correction in spondylitis tuberculosis cases. Developing the safest techniques and instrumentation is crucial to achieving spinal balance with minimal risk of morbidities.

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Kyphotic deformity is more than just a cosmetic problem.

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Kyphotic deformity is potentially life-threatening and disturbs quality of life.

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Deformity correction surgery is challenging.

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Cantilever technique is a gold standard to correct sagittal plane deformity.

Joint development recovery on resumption of embryonic movement following paralysis

Fetal activity in utero is a normal part of pregnancy and reduced or absent movement can lead to long-term skeletal defects, such as Fetal Akinesia Deformation Sequence, joint dysplasia and arthrogryposis. A variety of animal models with decreased or absent embryonic movements show a consistent set of developmental defects, providing insight into the aetiology of congenital skeletal abnormalities. At developing joints, defects include reduced joint interzones with frequent fusion of cartilaginous skeletal rudiments across the joint. At the spine, defects include shortening and a spectrum of curvature deformations. An important question, with relevance to possible therapeutic interventions for human conditions, is the capacity for recovery with resumption of movement following short-term immobilisation. Here, we use the well-established chick model to compare the effects of sustained immobilisation from embryonic day (E)4-10 to two different recovery scenarios: (1) natural recovery from E6 until E10 and (2) the addition of hyperactive movement stimulation during the recovery period. We demonstrate partial recovery of movement and partial recovery of joint development under both recovery conditions, but no improvement in spine defects. The joints examined (elbow, hip and knee) showed better recovery in hindlimb than forelimb, with hyperactive mobility leading to greater recovery in the knee and hip. The hip joint showed the best recovery with improved rudiment separation, tissue organisation and commencement of cavitation. This work demonstrates that movement post paralysis can partially recover specific aspects of joint development, which could inform therapeutic approaches to ameliorate the effects of human fetal immobility. This article has an associated First Person interview with the first author of the paper.

Mesenchymal Stem Cell-Specific and Preosteoblast-Specific Ablation of TSC1 in Mice Lead to Severe and Slight Spinal Dysplasia, Respectively

Background

TSC1-related signaling plays a pivotal role in intramembranous and endochondral ossification processes during skeletogenesis. This study was aimed at determining the significance of the TSC1 gene at different stages of spinal development. Materials and Methods. TSC1-floxed mice (TSC1^flox/flox) were crossed with Prrx1-Cre or BGLAP-Cre transgenic mice or mesenchymal stem cell- and osteoblast-specific TSC1-deficient mice, respectively. Somatic and vertebral differences between WT and Prrx1-TSC1 null mice were examined at 4 weeks after birth.

Results

No apparent body size abnormalities were apparent in newborn and 4-week- to 2-month-old mice with BGLAP-Cre driver-depleted TSC1. Vertebral and intervertebral discs displayed strong dysplasia in Prrx1-TSC1 null mice. In contrast, vertebrae were only slightly affected, and intervertebral discs from skeletal preparations displayed no apparent changes in BGLAP-TSC1 null mice.

Conclusion

Our data suggest that the TSC1 gene is crucial for endochondral ossification during postnatal spine development but plays discriminative roles at different stages. Mesenchymal stem cell-specific ablation of TSC1 led to severe spinal dysplasia at early stages of endochondral ossification while osteoblast-specific deletion of TSC1 affected vertebrae slightly and had no detectable effects on intervertebral discs.

Zebrafish and medaka as models for biomedical research of bone diseases

The identification of disease-causing mutations has in recent years progressed immensely due to whole genome sequencing approaches using patient material. The task accordingly is shifting from gene identification to functional analysis of putative disease-causing genes, preferably in an in vivo setting which also allows testing of drug candidates or biotherapeutics in whole animal disease models. In this review, we highlight the advances made in the field of bone diseases using small laboratory fish, focusing on zebrafish and medaka. We particularly highlight those human conditions where teleost models are available.

Short-term foetal immobility temporally and progressively affects chick spinal curvature and anatomy and rib development

Congenital spine deformities may be influenced by movements in utero, but the effects of foetal immobility on spine and rib development remain unclear. The purpose of the present study was to determine (1) critical time-periods when rigid paralysis caused the most severe disruption in spine and rib development and (2) how the effects of an early, short-term immobilisation were propagated to the different features of spine and rib development. Chick embryos were immobilised once per single embryonic day (E) between E3 and E6 and harvested at E9. To assess the ontogenetic effects following single-day immobilisation, other embryos were immobilised at E4 and harvested daily between E5 and E9. Spinal curvature, vertebral shape and segmentation and rib development were analysed by optical projection tomography and histology. The results demonstrated that periods critical for movement varied for different aspects of spine and rib development. Single-day immobilisation at E3 or E4 resulted in the most pronounced spinal curvature abnormalities, multiple wedged vertebrae and segmentation defects, while single-day immobilisation at E5 led to the most severe rib abnormalities. Assessment of ontogenetic effects following single-day immobilisation at E4 revealed that vertebral segmentation defects were subsequent to earlier vertebral body shape and spinal curvature abnormalities, while rib formation (although delayed) was independent from thoracic vertebral shape or curvature changes. A day-long immobilisation in chicks severely affected spine and rib development, highlighting the importance of abnormal foetal movements at specific time-points and motivating targeted prenatal monitoring for early diagnosis of congenital scoliosis.

Abnormal fetal muscle forces result in defects in spinal curvature and alterations in vertebral segmentation and shape

The incidence of congenital spine deformities, including congenital scoliosis, kyphosis, and lordosis, may be influenced by the in utero mechanical environment, and particularly by fetal movements at critical time-points. There is a limited understanding of the influence of fetal movements on spinal development, despite the fact that mechanical forces have been shown to play an essential role in skeletal development of the limb. This study investigates the effects of muscle forces on spinal curvature, vertebral segmentation, and vertebral shape by inducing rigid or flaccid paralysis in the embryonic chick. The critical time-points for the influence of fetal movements on spinal development were identified by varying the time of onset of paralysis. Prolonged rigid paralysis induced severe defects in the spine, including curvature abnormalities, posterior and anterior vertebral fusions, and altered vertebral shape, while flaccid paralysis did not affect spinal curvature or vertebral segmentation. Early rigid paralysis resulted in more severe abnormalities in the spine than later rigid paralysis. The findings of this study support the hypothesis that the timing and nature of fetal muscle activity are critical influences on the normal development of the spine, with implications for the understanding of congenital spine deformities. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2135-2144, 2017.

Automatic spine curvature estimation from X-ray images of a mouse model

Automatic segmentation and quantification of skeletal structures has a variety of applications for biological research. Although solutions for good quality X-ray images of human skeletal structures are in existence in recent years, automatic solutions working on poor quality X-ray images of mice are rare. This paper proposes a fully automatic solution for spine segmentation and curvature quantification from X-ray images of mice. The proposed solution consists of three stages, namely preparation of the region of interest, spine segmentation, and spine curvature quantification, aiming to overcome technical difficulties in processing the X-ray images. We examined six different automatic measurements for quantifying the spine curvature through tests on a sample data set of 100 images. The experimental results show that some of the automatic measures are very close to and consistent with the best manual measurement results by annotators. The test results also demonstrate the effectiveness of the curvature quantification produced by the proposed solution in distinguishing abnormally shaped spines from the normal ones with accuracy up to 98.6%.

Congenital kyphosis in thoracic spine secondary to absence of two thoracic vertebral bodies

Congenital thoracic kyphosis at D6-D7 vertebral body level has been encountered in an 18-month-old boy without neurological deficit. The constellation of the spine malformation complex such as incomplete development of the vertebral bodies associated with defective ossification of the thoracic pedicles causing effectively the development of spinal cord injury at the kyphotic level of D6-D7 were present. Congenital kyphosis in thoracic spine secondary to absence of two thoracic vertebral bodies has been reported in a few studies. It is the absence and asymmetry of growth plates that may contribute to a congenital defect. Congenital Kyphosis refers to the normal convex curvature of the spine as it occurs in the thoracic and sacral regions since birth. Congenital kyphosis is an uncommon, but potentially devastating anomaly of the spine. It is one of the important aetiology for spinal cord compression leading to further neurological complications. Congenital kyphosis although rare, is more associated with neurological complication. Early identification not only helps in understanding its natural history but also helps in deciding its management.

Abnormalities associated with congenital scoliosis: a retrospective study of 226 Chinese surgical cases

STUDY DESIGN

Retrospective study of a series of 226 consecutive Chinese patients with congenital scoliosis.

OBJECTIVE

To identify the incidence of intraspinal abnormalities and other organ defects in surgical patients with congenital scoliosis in Chinese population.

SUMMARY OF BACKGROUND DATA

Previous studies have revealed high rates of intraspinal anomalies and other organ defects in patients with congenital scoliosis. The incidence of abnormalities in patients with congenital scoliosis in Chinese population has not been reported.

METHODS

A total of 226 patients with congenital scoliosis underwent surgical treatment in Peking Union Medical College Hospital between January 2005 and March 2011 were identified. A definitive diagnosis of congenital scoliosis for all patients was made. Complete data were reviewed, including medical records, plain radiograph, magnetic resonance (MR) image of the whole spine, echocardiography, and renal ultrasound. The incidence of intraspinal abnormalities and other organ defects were analyzed.

RESULTS

Intraspinal abnormalities were found in 99 (43%) patients. Diastematomyelia was identified to be the most common intraspinal pathological anomaly, which was different from the previous reports. The incidence of intraspinal anomaly in patients with failures of segmentation and mixed defects were significantly higher than those with failures of formation. Patients with thoracic hemivertebrae were found to have a higher incidence of intraspinal abnormalities than patients with lumbar hemivertebrae. Patients with intraspinal abnormality had a higher incidence of positive clinical findings than those with normal magnetic resonance imaging. However, the difference between the 2 groups was not statistically significant. Other organic defects were found in 91(40%) patients. Cardiac defects were detected in 18%, urogenital anomalies in 12%, and gastrointestinal anomalies in 5% of the patients in this study.

CONCLUSION

Diastematomyelia was found to be the most common intraspinal pathological anomaly and cardiac defects were the most common extraspinal anomaly in surgical patients with congenital scoliosis in this study. Magnetic resonance imaging, echocardiography, and ultrasound should be part of routine evaluation in all congenital cases before surgery, no matter positive clinical findings were found or not.

LEVEL OF EVIDENCE

3.

Prevalence, distribution, and morphology of ossification of the ligamentum flavum: a population study of one thousand seven hundred thirty-six magnetic resonance imaging scans

STUDY DESIGN

Large scale, cross-sectional imaging study of a general population.

OBJECTIVES

To evaluate the prevalence, morphology, and distribution of ossification of the ligamentum flavum (OLF) in a population, and synthesize the scientific literature on the prevalence of OLF and some factors associated with its occurrence.

SUMMARY OF BACKGROUND DATA

OLF is a rare disease in which the pathogenesis has not been conclusively established. Little is known about its epidemiology. To date, there is no study that comprehensively assessed the distribution and prevalence of OLF in the whole spine using magnetic resonance imaging (MRI).

METHODS

A total of 1736 southern Chinese volunteers (1068 women; 668 men) between 8 and 88 years of age (mean, 38 years) were recruited by open invitation. MRI was administered to all the participants. T2-weighted, 5-mm spin-echo MRI sequences of the whole spine were obtained. Presence of OLF was identified as an area of low signal intensity in the T2 sagittal sequence located in the posterior part of the spinal canal, and subsequently confirmed by computed tomography scans showing areas of ossification within the ligamentum flavum. The distribution of OLF was classified into 3 types: the isolated type, continuous type, and noncontinuous type. While the morphology of the lesion was classified into triangular, round, and beak shapes based on the pattern of ossification on T2-weighted sagittal MRIs.

RESULTS

OLF was identified in a total of 66 subjects or 3.8% of the population (52 women and 14 men). In 45(68.2%) cases, OLF was present at a single-level (isolated type), whereas in 21 (31.8%) cases OLF was present at multiple levels. The isolated type was found in 45 (68.2%) cases, continuous type in 11 (16.7%), and noncontinuous type in 10 (15.2%). The most common site of involvement is the lower thoracic spine, but they can also occur in the upper thoracic spine. The majority of the segments had a round morphology (n = 75: 81.5%), while 17 (18.5%) segments were triangular in shape. A literature review of the past 26 years showed only 4 reports on the prevalence of OLF, all were in special patient groups.

CONCLUSION

Case reports have described postoperative paraplegia from failure to identify and decompress all stenotic segments of OLF. This study demonstrated that OLF is not uncommon, and that some 15% of the lesions are noncontinuous, and therefore could be missed. The authors recommend that for patients undergoing surgical decompression for 1 level of OLF, the whole spine should be routinely screened for other stenotic segments. Failure to do so could result in paraplegia from the nondecompressed levels.

Pediatric scoliosis and kyphosis

Pediatric spinal deformity is a common manifestation of multiple disorders. The clinical picture varies depending on the age at presentation, the severity of the curve at the time of diagnosis, and the underlying cause. Knowledge of the natural history of these varied conditions, the dynamics of growth in the developing spine, and normal axial skeletal biomechanics are fundamental in planning an appropriate treatment. Furthermore, in many instances the spinal anomaly is just part of the problem in a globally affected patient. Treatment alternatives must be judged based on their capacity to positively alter the natural course of the disease and provide a long-standing solution into a patient's adulthood.

Embryology of the spine and associated congenital abnormalities

BACKGROUND CONTEXT

The spine is a complex and vital structure. Its function includes not only structural support of the body as a whole, but it also serves as a conduit for safe passage of the neural elements while allowing proper interaction with the brain. Anatomically, a variety of tissue types are represented in the spine. Embryologically, a detailed cascade of events must occur to result in the proper formation of both the musculoskeletal and neural elements of the spine. Alterations in these embryologic steps can result in one or more congenital abnormalities of the spine. Other body systems forming at the same time embryologically can be affected as well, resulting in associated defects in the cardiopulmonary system and the gastrointestinal and genitourinary tracts.

PURPOSE

This article is to serve as a review of the basic embryonic development of the spine. We will discuss the common congenital anomalies of the spine, including their clinical presentation, as examples of errors of this basic embryologic process.

STUDY DESIGN/SETTING

Review of the current literature on the embryology of the spine and associated congenital abnormalities.

METHODS

A literature search was performed on the embryology of the spine and associated congenital abnormalities.

RESULTS

Development of the spine is a complex event involving genes, signaling pathways and numerous metabolic processes. Various abnormalities are associated with errors in this process.

CONCLUSION

Physicians treating patients with congenital spinal deformities should have an understanding of normal embryologic development as well as common associated abnormalities.

The crankshaft phenomenon after posterior spinal arthrodesis for congenital scoliosis: a review of 54 patients

STUDY DESIGN

Retrospective chart and radiographic reviews were conducted.

OBJECTIVE

To identify the incidence of and any possible risk factors for the crankshaft phenomenon after posterior spinal arthrodesis for congenital scoliosis.

SUMMARY OF BACKGROUND DATA

Studies have shown the crankshaft problem to be common after posterior arthrodesis for infantile and juvenile idiopathic scoliosis, but the few reports available show it to be much less common for congenital scoliosis.

METHODS

This study chose children fused before the pubertal growth spurt, all classified as Risser 0 and with open triradiate cartilages. These children were followed to the end of their growth (mean follow-up period 12 years). Several measurement parameters were used for evaluation.

RESULTS

The crankshaft problem, measured as a Cobb angle increase of more than 10 degrees, was seen in 15% of the 54 patients. There was a positive correlation with earlier surgery and larger (>50 degrees) curves. No other positive correlations could be identified.

CONCLUSIONS

Crankshafting was observed in 15% of the patients, more often with larger curves and earlier fusions.

Congenital spinal deformity: a comprehensive assessment at presentation

STUDY DESIGN

A series of 126 consecutive patients with congenital spinal deformity is presented.

OBJECTIVE

To assess the incidence of intraspinal anomaly and other organic defects associated with different types of spine deformity at presentation.

SUMMARY OF BACKGROUND DATA

A high incidence of intraspinal abnormalities and other organ defects is reported in relation to congenital spine deformity. The prevalence of these problems with different types of deformities is to be determined.

METHODS

All patients had MRI, echocardiography, renal ultrasound, and a thorough clinical assessment.

RESULTS

Intraspinal abnormalities were found in 47 patients (37%). These abnormalities were significantly more common in patients with congenital kyphosis ( = 0.0048), and in those with scoliosis resulting from mixed and segmentation defects. Scoliosis patients with cervical and thoracic hemivertebrae had significantly more intraspinal abnormalities ( = 0.0253) than those with lumbar hemivertebrae. In 64 (55%) patients other organic defects were found. These defects were more common in patients with congenital scoliosis resulting from mixed defects ( = 0.002). Cardiac defects were detected in 26% and urogenital anomalies in 21% of the patients.

CONCLUSIONS

Magnetic resonance imaging and echocardiography should be an essential part in the evaluation of patients with congenital spinal deformity, and special attention should be paid to patients with segmentation abnormalities, mixed defects, and kyphosis.