Hemivertebrae: a comprehensive review of embryology, imaging, classification, and management

The most common congenital malformations in dogs: Literature review and practical guide

Congenital malformations can affect almost 7% of canine newborns. The increase of commercial dog breeding and inbreeding used to maintain the striking characteristics of each breed, the appearance of malformations has become increasingly common, especially in brachycephalic dogs. The causes are diverse, and include genetic, nutritional, iatrogenic, and infectious factors, often making it difficult to establish a cause-consequence relationship. The high mortality associated with malformations comes not only from the fact that some are incompatible with life, but also because even if many undergo surgical treatment or correction, they require specific management, monitoring, and clinical treatment for an indefinite period of time. The most common malformations such as cleft lip and palate, hydrocephalus and anasarca have been studied for a long time, and it is currently known that brachycephalic dogs have a greater predisposition, however, for other less common conditions as gastroschisis and hypospadias, there is only a few case reports. The appearance of congenital defects in a litter leads to financial losses for the breeder, emotional losses for the owner and the veterinarian and harms the well-being of that individual. For this reason, the aim of this review article is to gather relevant information on the characteristics, diagnosis, and management of the main malformations in puppies. It is essential that the veterinarian is prepared to diagnose and treat these conditions, reducing negative impacts on animals and owners.

Hemivertebra with pathogenic microdeletion of chromosome 9

Hemivertebra is a rare congenital abnormality of the spinal column. Hemivertebra with other structural and cytogenetic abnormalities are reported. The prognosis is favorable with partial hemivertebra and with a single spinal defect as compared to a defect involving full segments and affecting different levels of the spines. The perinatal outcome is obscured when it is associated with other syndromes or cytogenetic abnormality. It is imperative to do serial thorough anatomical ultrasound scanning and to screen for chromosomal abnormality when hemivertebra is detected during pregnancy.

Morphological analysis of isolated hemivertebra: radiographic manifestations related to the severity of congenital scoliosis

PURPOSE

The natural history of congenital scoliosis (CS) caused by hemivertebra varies greatly. This study aimed to explore the association between the morphology of hemivertebra and the severity of CS, since the diagnosis of the hemivertebra.

METHODS

Patients with isolated (single fully segmented) hemivertebra were enrolled. The degree and progression of deformity were compared by three morphological parameters of hemivertebra, comprising whether the width of hemivertebra extends across the central vertical line of lower adjacent vertebra (midline); the lateral height ratio (LHR, lateral height of hemivertebra× 2/(lateral height of HV-1 plus HV + 1) with the cut-point being 0.9; and the sagittal position of hemivertebra that was divided into the lateral and posterolateral group.

RESULTS

In total, 156 patients (mean age 9.7 ± 6.2 years, 81 males) were enrolled. The number of thoracic, thoracolumbar (T12/13-L1), and lumbar hemivertebrae were 63, 41, and 52, respectively. Hemivertebrae across the midline had larger scoliosis and kyphosis (58.3 ± 20.6° vs. 42.8 ± 15.0°, P <  0.001; 45.1 ± 32.5° vs. 29.5 ± 25.7°, P = 0.013, respectively). Hemivertebrae with LHR ≥0.9 was associated with larger scoliosis (55.7 ± 20.6° vs. 41.4 ± 13.3°, P <  0.001). Larger scoliosis and kyphosis were observed in posterolateral hemivertebrae (54.4 ± 21.0° vs. 44.4 ± 15.6°, P = 0.026; 51.4 ± 31.5° vs. 20.6 ± 17.1°, P <  0.001, respectively). Co-occurrence of more than one of the three positive parameters above indicated higher annual progression (5.0 ± 2.2° vs. 3.3 ± 1.3°, P <  0.001).

CONCLUSION

Three positive parameters, width across the midline, LHR ≥0.9, and posterolateral position were associated with a more severe deformity in patients with isolated hemivertebra. Hemivertebrae with more than one positive parameter may cause progressive deformity, and thus need prompt surgery.

LEVEL OF EVIDENCE

Prognostic, level IV.

Molecular landscape of congenital vertebral malformations: recent discoveries and future directions

Vertebral malformations (VMs) pose a significant global health problem, causing chronic pain and disability. Vertebral defects occur as isolated conditions or within the spectrum of various congenital disorders, such as Klippel-Feil syndrome, congenital scoliosis, spondylocostal dysostosis, sacral agenesis, and neural tube defects. Although both genetic abnormalities and environmental factors can contribute to abnormal vertebral development, our knowledge on molecular mechanisms of numerous VMs is still limited. Furthermore, there is a lack of resource that consolidates the current knowledge in this field. In this pioneering review, we provide a comprehensive analysis of the latest research on the molecular basis of VMs and the association of the VMs-related causative genes with bone developmental signaling pathways. Our study identifies 118 genes linked to VMs, with 98 genes involved in biological pathways crucial for the formation of the vertebral column. Overall, the review summarizes the current knowledge on VM genetics, and provides new insights into potential involvement of biological pathways in VM pathogenesis. We also present an overview of available data regarding the role of epigenetic and environmental factors in VMs. We identify areas where knowledge is lacking, such as precise molecular mechanisms in which specific genes contribute to the development of VMs. Finally, we propose future research avenues that could address knowledge gaps.

Deformity or variation? Phenotypic diversity in the zebrafish vertebral column

Vertebral bodies are composed of two types of metameric elements, centra and arches, each of which is considered as a developmental module. Most parts of the teleost vertebral column have a one-to-one relationship between centra and arches, although, in all teleosts, this one-to-one relationship is lost in the caudal fin endoskeleton. Deviation from the one-to-one relationship occurs in most vertebrates, related to changes in the number of vertebral centra or to a change in the number of arches. In zebrafish, deviations also occur predominantly in the caudal region of the vertebral column. In-depth phenotypic analysis of wild-type zebrafish was performed using whole-mount stained samples, histological analyses and synchrotron radiation X-ray tomographic microscopy 3D reconstructions. Three deviant centra phenotypes were observed: (i) fusion of two vertebral centra, (ii) wedge-shaped hemivertebrae and (iii) centra with reduced length. Neural and haemal arches and their spines displayed bilateral and unilateral variations that resemble vertebral column phenotypes of stem-ward actinopterygians or other gnathostomes as well as pathological conditions in extant species. Whether it is possible to distinguish variations from pathological alterations and whether alterations resemble ancestral conditions is discussed in the context of centra and arch variations in other vertebrate groups and basal actinopterygian species.

C2 semisegmented hemivertebra - a rare anomaly presenting with torticollis

BACKGROUND

Cervical hemivertebrae are extremely rare anomalies which usually present with restriction of neck movements and torticollis in childhood. Hemivertebrae within the craniovertebral junction have only been reported once previously in the literature. We report a case of semisegmented C2 vertebra presenting in a young adult with cervical pain and torticollis with no other associated anomalies.

CASE DESCRIPTION

A 21-year-old lady presented with a history of neck pain for the past 10 days and longstanding torticollis with head tilt to the left. Computed tomographic scan of the cervical spine revealed a semisegmented hemivertebra located laterally between the C1 lateral mass and C2 on the right side which was not associated with any other bony anomalies, scoliosis or atlantoaxial dislocation. Conservative treatment with physical therapy was the chosen therapeutic strategy.

CONCLUSION

Hemivertebrae within the craniovertebral junction are exceedingly rare anomalies which may present with pain and deformity in childhood and are an important cause of congenital torticollis which may be associated with other spinal, craniofacial, cardiac or renal anomalies.

Oculoauriculofrontonasal syndrome: Refining the phenotype through a new case series and literature review

The oculoauriculofrontonasal syndrome (OAFNS) is a rare condition, with unknown etiology, characterized by the association of frontonasal dysplasia (FND) and oculoauriculovertebral spectrum (OAVS). Main clinical findings include widely spaced eyes, epibulbar dermoid, broad nose, mandibular hypoplasia, and preauricular tags. Here, we describe a case series of 32 Brazilian individuals with OAFNS and review the literature ascertaining individuals presenting phenotypes compatible with the diagnosis of OAFNS, aiming to refine the phenotype. This series emphasizes the phenotypic variability of the OAFNS and highlights the occurrence of rare craniofacial clefts as a part of the phenotype. The ectopic nasal bone, a hallmark of OAFNS, was frequent in our series, reinforcing the clinical diagnosis. The absence of recurrence, consanguinity, chromosomal, and genetic abnormalities reinforces the hypothesis of a nontraditional inheritance model. The phenotypic refinement provided by this series contributes to an investigation regarding the etiology of OAFNS.

Congenital Torticollis in a Child With Cervical Spine Deformity: A Case Report and Literature Review

Congenital torticollis is an abnormal tilt of the neck in a newborn especially on the side of the pathology with the chin pointing toward the contralateral side. The most frequent cause is termed congenital muscular torticollis (CMT) which is a structural abnormality in the muscle of the neck called sternocleidomastoid muscle. There are also other causes of congenital torticollis that may arise such as anomalies of the cervical vertebrae, syndromic causes, and ocular defects. Diagnosing these other causes of congenital torticollis requires careful examination, cervical X-ray, CT scan, and MRI. The objective of this review is to create an awareness of the different types and causes of cervical spinal deformity. It also confirms that it is easy to misdiagnose these rarer causes of congenital torticollis as seen in a clinical vignette of a newborn who was managed for CMT for about one year with physical therapy and later turned out to have an associated hemivertebrae and fusion of the second and third cervical vertebrae. It is rare but it has the burden of huge financial and psychosocial impact.

Evaluation and Comparation of a Novel Surgical Technique and Hemivertebra Resection to the Correction of Congenital Cervical Scoliosis in Lower Cervical and Cervicothoracic Spine

OBJECTIVE

To report concave-side distraction technique to treat congenital cervical scoliosis in lower cervical and cervicothoracic spine. To evaluate and compare clinical and radiographic results of this procedure with classic hemivertebra resection procedure.

METHODS

This study reviewed 29 patients in last 13 years. These patients were divided into convex-side resection group (group R) and concave-side distraction group (group D). Radiographic assessment was based on parameter changes preoperatively, postoperatively and at last follow-up. Demographic data, surgical data and complications were also evaluated and compared between the 2 groups.

RESULTS

In group R, mean age was 8.9 ± 3.3 years and follow-up was 46 ± 18 months. Operation time and blood loss averaged 500 ± 100 minutes, 703 ± 367 mL. In group D, mean age was 9.9 ± 2.8 years and follow-up was 34 ± 14 months. Operation time and blood loss averaged 501 ± 112 minutes, 374 ± 181 mL. Structural Cobb angle was corrected from 29.4° ± 12.5° to 5.3° (2.1°-18.1°) (p = 0.001) and 33.7° ± 14.1° to 12.8° ± 11.4° (p < 0.001) in groups R and D. Compensatory Cobb angle had a spontaneous correction rate of 59.6% (40.0%-80.8%) and 59.7% ± 23.0% in groups R and D. Mandibular incline, clavicle angle and spine coronal balance were significantly improved at last follow-up in both groups. All correction rates were not statistically different between groups. However, group D had significant less blood loss (p < 0.001) and operation time (p = 0.004) per vertebra than group R. Seven patients developed C5 nerve root palsy and recovered by 6 months of follow-up.

CONCLUSION

Both surgical procedures are safe and effective in correcting congenital cervical scoliosis. But concave-side distraction technique has less blood loss and time-consuming during surgery, which provides a better option for the treatment of congenital cervical scoliosis.

Umbilical cord-derived mesenchymal stem cells implantation on Hemivertebra defect with three-year follow-up: Biological approach in congenital scoliosis treatment - A case report

Introduction and importance

Congenital scoliosis is abnormal vertebral column growth and development during embryogenesis. The most common type of congenital scoliosis is failure of growth which is called as hemivertebra. However, the recent surgical treatment of hemivertebra has several complications especially in young patient. The mesenchymal stem cells (MSCs) have been used to treat several bone problems including bone defect and may be have potential to treat the defect in hemiverterbra. We reported a hemivertebra treated by umbilical cord-derived MSCs (UC-MSCs).

Case presentation

A two-year-old boy presented with scoliosis deformity. The mother noticed the patient's deformity when he was 10th month of age as he learned to stand and progressed since then. There were no growth and development problems. On physical examination, the patient appeared to have scoliosis at lumbar level with bending to the right and asymmetry of waist fold with left shoulder depression. Based on X-ray and CT-Scan investigations, the patient was diagnosed with single fully segmented hemivertebra at 3rd lumbar level. 20 × 10⁶ UC-MSCs were implanted into the bone defect of hemivertebra.

Clinical discussion

At three-year follow-up, the X-ray and MRI investigations showed a decrease of Cobb angle and increase of hemivertebra ratio. These findings may be due to improvement of the bone defect, which is consistent with several studies that MSCs have abilities to promote bone formation by maintaining the osteoblast cells and improving vascularization.

Conclusion

We found that MSCs therapy for hemivertebra represent a potential therapy to correct scoliosis curvature and prevent further curvature. Further clinical studies are required to investigate the efficacy of this therapy in hemivertebra.

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Hemivertebrae is due to the failure of development of vertebrae.

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Mesenchymal stem cells induce new bone formation.

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Symmetrical growth of the spine is required for prevent spinal deformity.

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Regenerative therapy using mesenchymal stem cells as treatment strategy for hemivertebra

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Implantation of mesenchymal stem cells in hemivertebra is safe procedure.

Prenatal Diagnosis and Outcomes in Fetuses with Hemivertebra

Background: There are few studies on the burden of chromosomal abnormalities and single gene disorders in fetal hemivertebra (HV). We aim to investigate the cytogenetic and monogenic risk and evaluate prenatal outcomes of fetal HV. Method: This study included fetuses diagnosed with HV divided into two groups: isolated HV and non-isolated HV. Data on other sonographic structural anomalies, chromosomal and sub-chromosomal abnormalities, monogenic variations detected by WES, and prenatal outcomes are recorded and reviewed. Results: Among 109 fetal HV cases, forty-seven (43.1%) non-isolated HV cases were associated with structural anomalies. Chromosomal test results were available in 58 cases, identifying six (10.3%) chromosomal aberrations involved in four isolated and two non-isolated HV. WES identified four (likely) pathogenic variants in three cases among 16 fetuses with HV, involving three novel variants, 1250G > T and c.1277G> inherited from parents, respectively, in DLL3 and c.7213C > A ** in the FLNB. The live birth rate (LB) was higher in the isolated fetal HV group than in the non-isolated group (67.7% (42/62) vs. 12.5% (12/47), p < 0.001). Conclusion: This study emphasizes the risk of cytogenetic abnormalities in isolated HV. WES yields a diagnostic rate of 18.3% in HV with normal CMA, probably aiding the prenatal counseling and management of fetal HV.

Vertebral anomalies in a natural population of Taricha granulosa (Caudata: Salamandridae)

Developmental plasticity, a common pattern in lissamphibian evolution, results in numerous alternative morphologies among species and also within populations. In the present study, a natural population of the salamander Taricha granulosa (Salamandridae) was examined to detect variation in the vertebral count and to identify potential deformities of their vertebral column. The number of trunk vertebrae varied between 11 and 13 and we recorded 58 individuals with 69 anomalous vertebral elements. These anomalies range from congenital malformations (block vertebrae, unilateral bars, hemivertebrae), extra ossifications in the haemal region, to posttraumatic pathologies. Most osseous pathologies were encountered in the caudal region of the axial skeleton. Our data suggest a high frequency of vertebral malformations in salamanders; however, the identification of the exact causes remains challenging.

Birth defect co-occurrence patterns in the Texas Birth Defects Registry

BACKGROUND

The population-level landscape of co-occurring birth defects among infants without a syndromic diagnosis is not well understood.

METHODS

We analyzed data from 40,771 infants with two or more major birth defects in the Texas Birth Defects Registry (TBDR; 1999-2014). We calculated adjusted observed-to-expected (O/E) ratios for all two, three, four, and five-way combinations of 138 major defects.

RESULTS

Among 530 patterns with the highest adjusted O/E ratios (top 5% of 10,595 patterns), 66% included only defects co-occurring within one organ system and 28% were suggestive of known patterns (e.g., midline developmental defects). Of the remaining patterns, the combination of defects with the highest O/E ratio (193.8) encompassed the diaphragm, spine, spleen, and heart defects. Fourteen patterns involved heart and spine defects with or without rib defects. Ten additional patterns primarily involved two hallmark components of VACTERL association (specifically, vertebral defects, anal atresia, cardiac defects, renal, or limb defects, but not tracheoesophageal fistula).

CONCLUSIONS

Our analyses provide a description of the birth defect co-occurrence patterns in a multi-ethnic, population-based sample, and revealed several patterns of interest. This work complements prior work that has suggested etiologic connections between select defects (e.g., diaphragmatic hernia and heart and spleen anomalies; heart and spine defects).

IMPACT

In this large-scale, population-based study of birth defect co-occurrence patterns, we found several birth defect combinations of potential interest that warrant further investigation: congenital diaphragmatic hernia, heart, spine, and spleen defects and scimitar syndrome with vertebral defects. The majority of patterns of co-occurring defects observed more frequently than expected involved multiple defects within the same system and combinations suggestive of known associations. Nearly all of the top patterns (beyond the same system and those suggestive of known associations) involved organ systems that are components of the VACTERL association, with heart, spine, and rib defect patterns being the most common.

Proposed clinical approach and imaging studies in families with oculo-auriculo-vertebral spectrum to assess variable expressivity

A diagnosis of oculo-auriculo-vertebral spectrum (OAVS) is established when microtia is present in association with hemifacial hypoplasia (HH) and/or ocular, vertebral, and/or renal malformations. There is no consensus on which imaging studies should be used to rule out variable expressivity and distinguish "sporadic" from "familial" patients. This observational and descriptive study was performed in a Mexican population of 51 patients (32 males, 19 females, 0-18 years old) with microtia/OAVS, and their available parents. A clinical history, genealogy, and physical examination were obtained from all included patients, as were a computed tomography (CT) scan of the ear, audiological evaluation, orthopantomography, complete spine radiography, and renal ultrasound. The same approach was completed in their available parents (51 mothers and 40 fathers), excluding the CT scan and audiological evaluation. By genealogy, 53% of patients were classified as "sporadic"; of the "familial" patients, at least 79.1% had suggestion of a multifactorial inheritance. In the available parents, orthopantomography, complete spine X-ray, and renal ultrasound identified the following OAVS-related manifestations: HH (16.2%, n = 14/86), vertebral alterations (10.9%, n = 10/91), and renal anomalies (2.2%, n = 2/90). Our evaluation of the parents allowed three patients to be reclassified from "sporadic" to "familial" (5.8%, n = 3/51). Our proposed clinical and imaging approach allowed the identification of variable expressivity that more clearly distinguished between "sporadic" and "familial" OAVS patients, which is of utmost importance in providing proper genetic counseling to these families.

First-Trimester Diagnosis of Supernumerary Hemivertebra

Hemivertebra is a common cause of congenital scoliosis and results from a lack of formation of one-half of the vertebral body. This condition is very rare and can present as solitary or as a syndrome component: i.e., the split notochord syndrome, which often implies vertebral defects, from a bifid vertebra to hemivertebrae, or fused vertebrae. We describe a case of supernumerary lateral hemivertebra detected prenatally at 12 weeks of gestation and the ultrasonography specifics that lead to early and accurate diagnosis, monitoring during pregnancy, and follow-up at the 4-year period. The case is presented to specify the importance of an early assessment of fetal spine and diagnosis of various conditions, including hemivertebrae, considering the significant association with other anomalies (cardiovascular, urinary, skeletal, gastrointestinal, and central nervous systems), which are most commonly involved. Moreover, the need to counsel future parents on the risks implied by this anomaly is important for the obstetrician. We underline the inclusion of these types of congenital conditions in high-risk pregnancy because of the frequent association with high cesarean delivery rates, growth restriction, delivery before term, and higher morbidity rates.

Congenital Cervical Hemivertebrae and Block Vertebrae in a 43-Year-Old Male

Congenital deformities of the spine are a consequence of anomalous vertebral development in the embryo and may be identified at birth or remain unnoticed until adulthood. Minor bony malformations of all types occur in up to 12% of the general population and are usually not apparent. In contrast, congenital spinal malformations that result in progressive spinal deformity are relatively rare. Klippel-Feil syndrome is a complex heterogeneous entity that results in cervical vertebral fusion and sometimes can occur associated to hemivertebra. We present a case of a 43-year-old male who presented to the emergency department after a fall. The patient had severe cervicalgia and generalized loss of active movement and sensation on his limbs. On physical examination, the patient presented reduced cervical range of motion and tetraplegia. Cervical magnetic resonance imaging revealed complete atlanto-occipital assimilation, left C3 hemivertebra with partial fusion in the right lateral portion of C2 and C4. Finally, there was a C5-C6 fusion. Surgical cervical stabilization was attempted but the procedure was aborted due to lack of space for placing the anterior plate safely. During hospitalization, the patient wore a cervical collar and started a rehabilitation program including muscle strengthening, balance, and gait training. The rehabilitation treatment led to a favorable clinical evolution. At discharge, the patient maintained a slight deficit of strength in his left upper and lower extremities, but he was functionally autonomous and was able to walk with a walker.

Neuroradiological findings in Alagille syndrome

Alagille syndrome (ALGS) is a multisystemic disease caused by mutations in genes of Notch pathway, which regulates embryonic cell differentiation and angiogenesis. Clinically, ALGS is characterized by cholestasis, cardiac defects, characteristic facial features, skeletal and ophthalmologic abnormalities. The aim of this review is to illustrate neuroradiological findings in ALGS, which are less well-known and prevalent, including cerebrovascular anomalies (such as aneurysms, dolichoectasia, Moyamoya syndrome and venous peculiarities), Chiari 1 malformation, craniosynostosis, intracranial hypertension, and vertebral anomalies (namely butterfly vertebra, hemivertebra, and craniocervical junction anomalies). Rarer cerebral midline malformations and temporal bone anomalies have also been described.

Two-staged posterior osteotomy surgery in complex and rigid congenital scoliosis in younger than 10 years old children

Background

Congenital scoliosis caused by failure of multiply vertebral segmentation with concave fused rib or unsegmented bar combined with contralateralhemivertebra is usually rigid and produces enormous asymmetric growth. Fusionless techniques have less advantage and come with some complications. Paucity of data was reported for children with complex congenital scoliosis using two-staged osteotomy surgery.

Methods

From 2006 to 2016, 11 patients less than 10 years old undergoing two staged osteotomy surgery for complex rigid congenital scoliosis were retrospectively reviewed. The analysis included age at initial surgery, second surgery and at the latest follow-up, and complications. Changes in coronal major curve, thoracic kyphosis, lumbar lodorsis, apex vertebra translation, T1-T12 length, T1-S1 length, trunk shift, and SVAwere included in radiological evaluation.

Results

In all, the mean follow-up was 72.5 ± 23.8 (42 to 112) months. The mean flexibility of the spine was 17.4 and 17.8 % before two surgeries. The mean age at the initial surgery was 6.6 ± 2.6 (2.5–10) years. The mean fusion level was 4.6 ± 1.3 (2 to 6) segments. The mean scoliosis improved from 67.4° to 23.7° after initial surgery and was 17.4° at the latest follow-up. The average increase of T1-S1 length was 0.92 cm per year. No patients had neurological complications.

Conclusions

Two-staged osteotomy surgery including hemivertebrae resection or Y-shaped osteotomy can achieve good radiological and clinical outcomes without severe complications. This procedure can be an option of treatment for complex congenital scoliosis.

The Clinical and Radiologic Outcomes of Patients With Different 3-Dimensional Hemivertebra Morphologies Undergoing Posterior-Only Hemivertebra Resection and Fusion

OBJECTIVE

To compare the clinical and radiologic outcomes of patients with different 3-dimensional (3D) hemivertebra morphologies undergoing posterior-only hemivertebra resection and fusion.

METHODS

The files of patients with congenital scoliosis (CS) due to single hemivertebra undergoing posterior-only hemivertebra resection and fusion from January 2010 to January 2018 were reviewed. After evaluating the 3D computed tomography images, CS patients were divided into a unison hemivertebra group and a discordant hemivertebra group. Clinical outcomes, radiologic outcomes, and incidence of complications were compared.

RESULTS

A total of 42 consecutive patients with CS patients due to a single hemivertebra undergoing posterior-only hemivertebra resection and fusion were included in this study. The Cobb angle of the segmental curve was significantly improved postoperatively and at the last follow-up in both groups (all P < 0.05). At both postoperation and the last follow-up, no significant differences were found in the incidence of complications, Cobb angle of the segmental curve, correction rate of the segmental curve, or other radiologic outcomes between the unison hemivertebra group and discordant hemivertebra group (all P > 0.05). Compared with the unison hemivertebra group, increased operation time (P = 0.006) and intraoperative blood loss (P = 0.037) were found in the discordant hemivertebra group.

CONCLUSIONS

For CS patients with unison hemivertebra or discordant hemivertebra, satisfactory radiologic results were obtained by posterior-only hemivertebra resection and fusion. In terms of surgery, the radiologic outcomes of discordant hemivertebra patients were similar to those of unison hemivertebra patients, but discordant hemivertebrae could easily result in longer operation time and more intraoperative blood loss.

Selective hemivertebrae resection in congenital scoliosis with multiple hemivertebrae

There are no established guidelines regarding the surgical strategy to be adopted in congenital scoliosis with multiple hemivertebrae-decision has to be guided taking into account the contribution of each hemivertebra to the deformity and its growth potential. We describe a case of a 12-year-old woman with congenital scoliosis due to unbalanced multiple hemivertebrae. Preoperative imaging revealed the presence of three hemivertebrae-at D7, D10 and L5. Our surgical strategy was guided by various factors-the morphology of the hemivertebrae, the location, the contribution of each hemivertebra to the deformity and their relationship to each other. Based on this, we performed a selective hemivertebrae resection-completely resecting L5 hemivertebra and performing 'egg-shell' decancellation of D7 hemivertebra and in situ fusion of D10 hemivertebra, yielding satisfactory results. This case report illustrates a rational thought process that can guide a paediatric spinal deformity surgeon in treating scoliosis with multiple hemivertebrae.

Three-Dimensional Printing Technology for Surgical Correction of Congenital Scoliosis Caused by Hemivertebrae

OBJECTIVE

This study aimed to explore the clinical application of three-dimensional (3D) printing technology in the surgical treatment of congenital scoliosis caused by hemivertebrae.

METHODS

Twenty-four patients (11 in the 3D-printing group and 13 in the conventional group) with scoliosis secondary to a single hemivertebra were retrospectively reviewed. All patients underwent hemivertebrectomy and short-segment fixation. Virtual preoperative planning, operation simulation, and intraoperative application of 3D-printed patient-specific templates were performed in the 3D-printing group. Hemorrhage volume, operation time, transfusion, and complications were noted. Radiographic parameters were evaluated preoperatively, postoperatively, and at final follow-up.

RESULTS

All patients had different degrees of successfully corrected scoliosis. There was a similar correction of the Cobb angle postoperatively between the 2 groups. The operation time, blood loss, transfusion, time for the insertion of each screw, accuracy of screw placement, and complication rate in the 3D-printing group were significantly superior to those in the control group. No patient experienced major complications. No significant correction loss or instrument dysfunction was observed during follow-up.

CONCLUSIONS

As a viable and effective auxiliary technology, 3D printing makes it possible for surgery to meet both surgeon-specific and patient-specific requirements. 3D-printed individualized templates allow surgery for the correction of congenital scoliosis to enter a new stage of personalized precision surgery.

Lumbar hemivertebra resection in congenital scoliosis utilizing cone-beam navigation: less radiation, more accuracy-proof of concept

PURPOSE

To present the first known pediatric utilization of cone-beam navigation system (CBNS) for hemivertebra resection and spondylodesis CASE PRESENTATION: A 14-year-old female with congenital scoliosis, diagnosed at 8 years of age, presenting with progressive symptoms, a Cobb angle (L3-5) of 38° at time of surgery, treated historically with conservative measures. Presence of spinal intramedullary disease was excluded prior to operation via whole spine MRI.

RESULTS

Patient successfully underwent surgical correction utilizing the CBNS (O-arm™, Medtronic®). Post-operative Cobb angle (L3-5) was restored to 8°. Following four different pediatric patient's radiation exposures (two receiving correction via the O-arm platform and two via the traditional method employing fluoroscopy), we show a reduction in radiation exposure using the CBNS system.

CONCLUSION

We present the first known pediatric case of the utilization of the CBNS system for hemivertebra correction. We demonstrate that utilizing the CBNS platform can not only increase surgical accuracy but also decrease pediatric patient's radiation exposure as a preoperative CT scan is not needed. Future studies should continue to explore additional benefits of implementing the system into surgical practice.

Individualized Study of Posterior Hemivertebra Excision and Short-Segment Pedicle Screw Fixation for the Treatment of Congenital Scoliosis

OBJECTIVES

To compare the surgical effect of children with symmetrical screw fixation and asymmetric screw fixation during posterior hemivertebra excision and short-segment pedicle screw fixation for the treatment of congenital scoliosis (CS).

METHODS

A total of 30 children with CS who underwent posterior hemivertebra excision and short-segment bilateral pedicle screw fixation in our hospital from 2012 to 2018 were retrospectively included and were divided into two groups: symmetric fixation group (n = 18) and asymmetric fixation group (n = 12). The total main curve, segmental main curve, cranial compensatory curve, caudal compensatory curve, coronal balance, and apical vertebra translation were measured in the coronal plane. The segmental kyphosis, thoracic kyphosis, lumbar lordosis, and sagittal balance were measured in the sagittal plane.

RESULTS

Of the 30 children, 28 hemivertebrae were resected. Twenty-two children had one hemivertebra, three had two hemivertebrae, and five were rib deformities. The average operation time was 268 min (180-420 min). The average blood loss was 291 mL (150-550 mL). The average follow-up was 21.1 months (12-47 months). For symmetric fixation group and there were significant differences among postoperative and follow-up parameters including the total main curve, segmental main curve, cranial compensatory curve, caudal compensatory curve, apical vertebra translation and segmental kyphosis compared with those of preoperative parameters (P < 0.05). The postoperative coronal balance was significantly lower than preoperative coronal balance (P < 0.05). The follow-up thoracic kyphosis was significantly higher than preoperative and postoperative thoracic kyphosis (P < 0.05). For asymmetric fixation group, the postoperative and follow-up parameters including the total main curve, segmental main curve, cranial compensatory curve, caudal compensatory curve, apical vertebra translation, and segmental kyphosis had statistical differences compared with those of preoperative parameters (P < 0.05). The postoperative sagittal balance was significantly higher than preoperative postoperative (P < 0.05). There were no significant differences in the postoperative and follow-up correction rate and correction loss between the two groups (P > 0.05). There were three complications in 30 children in our study, including two cases who had poor wound healing, and the wound healed smoothly after half a month of sterile dressing change. Postoperative curve progression occurred in one case after T₁₂ and L₃ hemivertebra resection and thoracic hemivertebra resection was planned again.

CONCLUSION

For pedicles which were difficult for screw fixation, adjacent segments can be chosen for screw fixation and it is safe and effective for vertebral pedicles ≤3 without internal fixation.

Twin pregnancy complicated with congenital Hemivertebra: report of two cases and literature review

Background

Hemivertebra deformity, involving one or multiple vertebral bodies, is one of the important causes of congenital scoliosis. Congenital fetal hemivertebrae could be diagnosed by ultrasonography and confirmed by fetal magnetic resonance imaging during pregnancy. However, reports of hemivertebrae in twins during the perinatal period are very rare.

Case presentation

We report two cases of congenital fetal hemivertebrae, each affecting one fetus in a dichorionic diamniotic (DCDA) twin pregnancy. We have also conducted a literature review of its prenatal screening, diagnosis, management, and outcomes. These two cases of congenital fetal hemivertebrae in one fetus of a DCDA twin were both initially found by ultrasonography and confirmed by fetal magnetic resonance imaging (MRI). One couple chose selective termination of the hemivertebrae fetus after they were extensively counseled by the multidisciplinary team regarding the treatment and prognosis of the hemivertebrae twin, and a healthy baby weighing 2320 g was delivered at the 37^+ 1 gestational week. The other couple decided to continue the twin pregnancy and gave birth to two living newborns weighing 2580 g and 2060 g at 37^+ 1 gestational weeks. These three babies were all in good health during follow-up.

Conclusions

Based on our center’s experience, comprehensive ultrasonography is necessary for early prenatal diagnosis of this condition. In addition, fetal MRI will confirm the diagnosis of hemivertebrae and provide parents with helpful information for their decision about the fate of the affected fetus.

Anatomical Variations That Can Lead to Spine Surgery at The Wrong Level: Part II Thoracic Spine

Spine surgery at the wrong level is a detrimental ordeal for both surgeon and patient, and it falls under the wrong-site surgery sentinel events reporting system. While there are several methods designed to limit the incidence of these events, they continue to occur and can result in significant morbidity for the patient and malpractice lawsuits for the surgeon. In thoracic spine, numerous risk factors influence the development of this misadventure. These include anatomical variations such as transitional vertebrae, rib variants, hemivertebra, and block/fused vertebrae as well as patient characteristics, such as tumors, infections, previous thoracic spine surgery, obesity, and osteoporosis. An extensive literature search of the PubMed database up to 2019 was completed on each of the anatomical entities and their influence on developing thoracic spine surgery at the wrong level, taking into consideration patient’s individual factors. A reliable protocol and effective techniques were described to prevent this error. In addition, the surgeon should collaborate with radiologists, particularly in challenging cases. A thorough understanding of the surgical anatomy and its variants coupled with patients characteristic is crucial for maximal patient benefit and avoidance of thoracic spine surgery at the wrong level.

Pathological Features and Surgical Strategies of Cervical Deformity

Cervical deformity (CD) is a kind of disorder influencing cervical alignment. Although the incidence of CD is not high, this deformity can cause not only pain but also difficulties in daily activities such as swallowing and maintaining upright position. Even though the common cause of cervical deformity is still controversial, previous studies divided CD into congenital deformity and secondary deformity; secondary deformity includes iatrogenic and noniatrogenic deformity according to pathogenic factors. Due to the lack of relevant studies, a standardized evaluation for CD is absent. Even though the assessment of preoperative condition and surgical planning mainly rely on personal experience, the evaluation methods could still be summarized from previous studies. The objective in this article is to summarize studies on cervical scoliosis, identify clinical problems, and provide directions for researchers interested in delving deep into this specific topic. In this review, we found that the lack of standard classification system could lead to an absence of clinical guidance; in addition, the osseous landmarks and vascular distributions could be variable in CD patients, which might cause the risk of vascular or neurological complications; furthermore, multiple deformities were usually presented in CD patients, which might cause chain reaction after the correction of CD; this would prevent surgeons from choosing realignment surgery that is effective but risky.

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.

Posterior hemivertebral resection for upper thoracic congenital scoliosis: be aware of high risk of complications

The treatment of congenital hemivertebrae in the upper thoracic region is challenging. The objective of this study was to investigate the outcomes of posterior hemivertebral resection for the upper thoracic region. Twenty-one patients diagnosed with upper thoracic congenital scoliosis were included. All of them received hemivertebral resection surgery via the posterior-only approach with at least 2 years of follow-up. The radiographic parameters and Scoliosis Research Society-22 score were analyzed. All the intraoperative and postoperative complications were recorded retrospectively. The segmental main curve was 35.9° before surgery and 7.0° at the last follow-up, with an average correction rate of 80.2%. The total main curve was 44.1° before surgery and 11.6° at the last follow-up, with an average correction rate of 73.9%. The caudal compensatory curve was corrected from 20.2° to 7.1°, with an average correction rate of 64.9%. The segmental kyphosis was corrected from 30.9° to 8.9°, with an average correction rate of 65.5%. The total Scoliosis Research Society-22 score significantly improved in all patients at the last follow-up, mainly resulting from the improvement of the self-image, mental health, and satisfaction domains. The following complications were found: one pedicle fracture, two malpositioned screws, one transient neurologic deficit, one implant failure, and four postoperative curve progressions. Although good radiographic deformity correction and clinical results were achieved after surgery, the incidence rate of complications was high at 42.9%; great care should be taken to prevent them, especially for postoperative curve progression (19.0%).

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.

Efficacy and safety of one-stage posterior hemivertebral resection for unbalanced multiple hemivertebrae: A more than 2-year follow-up

OBJECTIVE

One-stage posterior hemivertebral resection has been proven to be an effective, reliable surgical option for treating congenital scoliosis due to a single hemivertebra. To date, however, no studies of treating unbalanced multiple hemivertebrae have appeared. This study evaluated the efficacy and safety of one-stage posterior hemivertebral resection for unbalanced multiple hemivertebrae.

PATIENTS AND METHODS

Altogether, we studied 15 patients with unbalanced multiple hemivertebrae who had undergone hemivertebral resection using the one-stage posterior approach with at least 2 years of follow-up. Clinical outcomes were assessed radiographically and with the Scoliosis Research Society-22 (SRS-22) score. Related complications were also recorded.

RESULTS

The mean Cobb angle of the main curve was 62.4° (46°-98°) before surgery and 18.2° (9°-33°) at the most recent follow-up (average correction 73.3%). The compensatory cranial curve was corrected from 28.5° (11°-52°) to 9.1° (0°-30°) (average correction 70.0%). The compensatory caudal curve was corrected from 31.6° (14°-54°) to 6.9°(0°-19°) (average correction 79.1%). The segmental kyphosis/lordosis was corrected from 41.1° (-40° to 98°) to 12.3° (-25° to 41°) (average correction 65.5%). The mean growth rate of the T1-S1 length in immature patients was 9.8mm/year during the follow-up period. Health-related quality of life (SRS-22 score) had significantly improved. Complications include one wound infection and one developing deformity.

CONCLUSION

One-stage posterior hemivertebral resection for unbalanced multiple hemivertebrae provides good radiographic and clinical outcomes with no severe complications when performed by an experienced surgeon. Longer follow-up to detect late complications is obligatory.

Childhood angular kyphosis: a plea for involvement of the pediatric neurosurgeon

INTRODUCTION

Childhood angular kyphosis is rare, as most children are affected by a mixed kyphotic and scoliotic deformity. Published series involving a mix of kyphosis and kyphoscoliosis, pediatric and adult, congenital and acquired cases are almost exclusively authored by orthopedic surgeons, suggesting that (pediatric) neurosurgeons are not involved.

CASE SERIES

We present five cases that illustrate the spectrum of angular kyphosis, and these were treated by a multidisciplinary team including child neurologist, orthopedic surgeon, and pediatric neurosurgeon as complementary partners.

DISCUSSION

Angular kyphosis is a cosmetic problem but above all a serious threat to the spinal cord and as such to the child's ambulatory, sphincter, and genito-urinary functions. Spinal cord stretch over the internal kyphosis may cause pain and/or neurological deficit, often accompanied by myelomalacia or even segmental cord atrophy. Spinal cord function may be additionally affected by associated disorders such as syringomyelia or tethered cord, an orthopedic surgeon may be less familiar with. The decision when and how to proceed surgically should be made by a multidisciplinary team, including a pediatric neurosurgeon who actively participates in the operation and helps to safely achieve adequate spinal cord decompression and stabilization.

CONCLUSION

Childhood angular kyphosis is a complex, heterogeneous disorder that should be managed by a multidisciplinary team in specialized pediatric spine centers. While every case is truly unique, the spinal cord is always at risk, especially during decompression, stabilization, and eventual correction of deformity. Pediatric neurosurgeons have an important role to play in preoperative work-up, actual operation, and follow-up.