Spinal disorders associated with skeletal dysplasias and syndromes

An original preoperative orthopaedic management of a complex spinal deformity in a 16-year-old patient with spondyloepiphyseal dysplasia congenita

PURPOSE

Spinal deformities in patients with Spondyloepiphyseal Dysplasia congenita are particularly challenging to treat. Addressing these deformities requires a holistic surgical strategy. The aim of this case report is to highlight an original preoperative protocol combining atlantoaxial instability stabilization by halo jacket with progressive correction of a thoracic kyphoscoliosis using continuous elongation by tension plaster cast as described by Stagnara.

METHOD

A 16-year-old patient with spondyloepiphyseal dysplasia congenita presenting a severe thoracic kyphoscoliosis associated with atlantoaxial instability causing cervical myelopathy was managed through a preoperative protocol combining a halo jacket with a Stagnara elongation cast allowing progressive correction of the kyphoscoliosis while stabilizing the cervical instability.

RESULTS

The preoperative protocol allowed a safer and a more effective surgical spine fusion, reducing neurological risks, improving the final correction, and offering better postoperative recovery. Clinical and radiological solid fusion was observed at 3-year-follow-up with significant improvement of the patient's quality of life.

CONCLUSION

This case report highlights the effectiveness of the preoperative preparation combining a halo jacket with a Stagnara elongation cast to safely stabilize the cervical spine while correcting the thoracic kyphoscoliosis. This strategy can serve as a valuable tool for spine teams when addressing complex spinal deformities particularly in this patient with SEDc.

LEVEL OF EVIDENCE

Level IV.

Atlantoaxial Subluxation in a 10-Year-Old Girl With Down Syndrome: A Case Report

Down syndrome is the most common inherited chromosomal disorder caused by trisomy 21. Atlantoaxial instability (AAI) is more common in children with Down syndrome, resulting from ligament laxity and odontoid dysplasia. We report the case of a 10-year-old girl with Down syndrome submental. She came to the ER with a history of abnormal gait for one week and was admitted with a case of ataxia for investigations. Moreover, we discovered that she had atlantoaxial subluxation, which was treated surgically.

Fifteen-minute consultation: Evaluation of paediatric torticollis

Torticollis refers to a state in which the neck is twisted due to excessive contraction or shortening of the muscles on one side. Congenital muscular torticollis, which is more common than acquired torticollis, has an incidence of 0.3%-1.9% among all live births. The clinical approach to torticollis depends on the age at presentation, duration of torticollis and presenting symptoms. The underlying aetiology for torticollis varies with the age of the child. Torticollis can be a presenting feature for life-threatening conditions and thus requires careful evaluation.

Elongation-Derotation-Flexion Casting Treatment of Early-Onset Progressive Scoliosis in Skeletal Dysplasia

BACKGROUND

Early-onset scoliosis in children with skeletal dysplasia is progressive, contributing to cardiopulmonary restrictive disease. Serial elongation-derotation-flexion (EDF) casting, used in other etiologies of scoliosis to delay curve progression, may be beneficial in maximizing spine growth. Our hypothesis is serial EDF casting can be safely used as a temporary alternative to surgery, delaying progression and preserving growth, to treat scoliosis in skeletal dysplasia.

METHODS

All patients with skeletal dysplasia treated at a single institution with serial EDF casting for scoliosis were reviewed retrospectively. Radiographic parameters: Cobb angle of major and minor curves, curve location, thoracic height, thoracolumbar height, space available for lung, and rib vertebra angle difference were measured before casting (C1), in first casting (C2), in last casting (C3), and out of last casting (C4). Peak inspiratory pressure (PIP) values were monitored and recorded during the casting application.

RESULTS

Eleven patients met the inclusion criteria (mean 9.7 castings). The mean duration of EDF serial casting was 35 months. The mean major Cobb angles were 54 degrees° (C1), 30 degrees (C2), 37 degrees (C3), and 49 degrees (C4) with no statistically significant differences. The mean minor Cobb angles were 35 degrees (C1), 25 degrees (C2), 33 degrees (C3), and 51 degrees (C4) with no statistically significant differences. The mean thoracic heights were 130 mm (C1), 155 mm (C2), 173 mm (C3), and 160 mm (C4). The 19-mm mean difference between C2 and C3 represents spinal growth. The PIP-1, PIP-2, and PIP-3 mean values were 15, 27, and 18 cmH2O, respectively. Changes in PIP-1 and PIP-2 and PIP-2 and PIP-3 were statistically significant.

CONCLUSION

Serial EDF casting can delay surgical scoliosis correction in children younger than 7 years with a diagnosis of skeletal dysplasia. Our study showed that serial casting controls progression of the major curve and allows longitudinal growth of the spine with possible expansion of lung volume for nearly 3 years. During cast application, PIP increased with molding and traction, and improved until windowing and trimming of the cast.

LEVEL OF EVIDENCE

Level IV-retrospective study.

Three-Dimensional-Printed Drill Guides for Occipitothoracic Fusion in a Pediatric Patient With Occipitocervical Instability

BACKGROUND

Pediatric occipitothoracic fusion can be challenging because of small size pedicles and thin occipital bone. Three-dimensional (3D) printing technology can help with accurate screw insertion but has not been described for occipital keel plate positioning so far.

OBJECTIVE

To describe the novel use of 3D technology to position occipital keel plates during pediatric occipitothoracic fixation.

METHODS

A young boy with segmental spinal dysgenesis presented with asymmetrical pyramidal paresis in all limbs. Developmental abnormities of the cervical spine caused a thinned spinal cord, and because of progressive spinal cord compression, surgical intervention by means of occipitothoracic fixation was indicated at the age of 3 yr.Because of the small-size pedicles and thin occipital bone, the pedicle screws and occipital plates were planned meticulously using 3D virtual surgical planning technology. The rods were virtually bent in order to properly align with the planned screws. By means of 3D-printed guides, the surgical plan was transferred to the operating theater. For the occipital bone, a novel guide concept was developed, aiming for screw positions at maximal bone thickness.

RESULTS

The postoperative course was uneventful, and radiographs showed good cervical alignment. After superimposing the virtual plan with the intraoperative acquired computed tomography, it was confirmed that the occipital plate positions matched the virtual plan and that pedicle screws were accurately inserted without signs of breach.

CONCLUSION

The use of 3D technology has greatly facilitated the performance of the occipitothoracic fixation and could, in the future, contribute to safer pediatric spinal fixation procedures.

A Heterozygous Missense Variant in MAP2K2 in a Stillborn Romagnola Calf with Skeletal-Cardio-Enteric Dysplasia

Simple Summary

Skeletal dysplasias encompass a clinical-, pathological- and genetically heterogeneous group of disorders characterized by abnormal cartilage and/or bone formation, growth, and remodeling. They may belong to the so-called RASopathies, congenital conditions caused by heterozygous variants in genes that encode components of the Ras/mitogen-activated protein kinase (MAPK) cell signaling pathway. Herein, an affected calf of the Italian Romagnola breed was reported showing a skeletal-cardio-enteric dysplasia. We identified a most likely disease-causing mutation in the MAP2K2 gene by whole-genome sequencing (WGS). The MAP2K2 gene is known to be related with dominant inherited cardio-facio-cutaneous syndrome in humans, but it was so far unknown to cause a similar disease in domestic animals. We assume that the identified missense variant that was predicted to impair the function of the protein, occurred either within the germline of the dam or post-zygotically in the embryo. Rare lethal diseases such as the skeletal-cardio-enteric dysplasia in livestock are usually not characterized to the molecular level, mainly because of the lack of funds and diagnostic opportunities. Precise WGS-based diagnostics enables the understanding of rare diseases and supports the value of monitoring cattle breeding populations for fatal genetic defects.

Abstract

RASopathies are a group of developmental disorders caused by dominant mutations in genes that encode components of the Ras/mitogen-activated protein kinase (MAPK) cell signaling pathway. The goal of this study was to characterize the pathological phenotype of a Romagnola stillborn calf with skeletal-cardio-enteric dysplasia and to identify a genetic cause by whole-genome sequencing (WGS). The calf showed reduced fetal growth, a short-spine, a long and narrow face, cardiac defects and heterotopy of the spiral colon. Genetic analysis revealed a private heterozygous missense variant in MAP2K2:p.Arg179Trp, located in the protein kinase domain in the calf, and not found in more than 4500 control genomes including its sire. The identified variant affecting a conserved residue was predicted to be deleterious and most likely occurred de novo. This represents the first example of a dominant acting, and most likely pathogenic, variant in MAP2K2 in domestic animals, thereby providing the first MAP2K2-related large animal model, especially in respect to the enteric malformation. In addition, this study demonstrates the utility of WGS-based precise diagnostics for understanding sporadic congenital syndromic anomalies in cattle and the general utility of continuous surveillance for rare hereditary defects in cattle.

An unusual injury mechanism of atlantoaxial dislocation: illustrative case

BACKGROUND

Atlantoaxial dislocation (AAD) is a rare and potentially life-threatening condition. Various underlying mechanisms of injury are described in the literature. Here, the authors report an unusual nontraumatic injury mechanism of AAD in a 12-year-old patient.

OBSERVATIONS

A 12-year-old boy presented with intolerable neck pain and numbness in both upper limbs. The patient’s symptoms had started 2 months after the initiation of online classes during the coronavirus disease 2019 pandemic without a history of trauma. He used a computer for personal study and online classes for prolonged hours with no respite. On physical and radiological evaluation, he was diagnosed with AAD. Before surgery, skull traction was applied to reduce the dislocation and posterior C1 lateral mass screw and C2 pedicle screw fixation was performed. An optimal clinical outcome was achieved with no postoperative complications. A preoperative visual analog scale score of 8.0 was reduced to 0 postoperatively.

LESSONS

A prolonged fixed neck posture is an unusual underlying cause of AAD. Posterior C1 lateral mass and C2 pedicle screw fixation results in an optimal clinical outcome.

Identification of clinical and radiographic predictors of central nervous system injury in genetic skeletal disorders

Some studies report neurological lesions in patients with genetic skeletal disorders (GSDs). However, none of them describe the frequency of neurological lesions in a large sample of patients or investigate the associations between clinical and/or radiological central nervous system (CNS) injury and clinical, anthropometric and imaging parameters. The project was approved by the institution’s ethics committee (CAAE 49433215.5.0000.0022). In this cross-sectional observational analysis study, 272 patients aged four or more years with clinically and radiologically confirmed GSDs were prospectively included. Genetic testing confirmed the diagnosis in the FGFR3 chondrodysplasias group. All patients underwent blinded and independent clinical, anthropometric and neuroaxis imaging evaluations. Information on the presence of headache, neuropsychomotor development (NPMD), low back pain, joint deformity, ligament laxity and lower limb discrepancy was collected. Imaging abnormalities of the axial skeleton and CNS were investigated by whole spine digital radiography, craniocervical junction CT and brain and spine MRI. The diagnostic criteria for CNS injury were abnormal clinical and/or radiographic examination of the CNS. Brain injury included malacia, encephalopathies and malformation. Spinal cord injury included malacia, hydrosyringomyelia and spinal cord injury without radiographic abnormalities. CNS injury was diagnosed in more than 25% of GSD patients. Spinal cord injury was found in 21.7% of patients, and brain injury was found in 5.9%. The presence of low back pain, os odontoideum and abnormal NPMD remained independently associated with CNS injury in the multivariable analysis. Early identification of these abnormalities may have some role in preventing compressive CNS injury, which is a priority in GSD patients.

Sitting Height to Standing Height Ratio Reference Charts for Children in the United States

OBJECTIVE

To create reference charts for sitting height to standing height ratio (SitHt/Ht) for children in the US, and to describe the trajectory of SitHt/Ht during puberty.

STUDY DESIGN

This was a cross-sectional study using data from the 1988-1994 National Health and Nutrition Examination Survey III, a strategic random sample of the US population. Comparison between non-Hispanic White (NHW), non-Hispanic Black (NHB) and Mexican American groups was performed by ANOVA to determine if a single population reference chart could be used. ANOVA was used to compare SitHt/Ht in pre-, early, and late puberty.

RESULTS

NHANES III recorded sitting height and standing height measurements in 9569 children aged 2-18 years of NHW (n = 2715), NHB (n = 3336), and Mexican American (n = 3518) ancestry. NHB children had lower SitHt/Ht than NHW and Mexican American children throughout childhood (P < .001). In both sexes, the SitHt/Ht decreased from prepuberty to early puberty and increased in late puberty. Sex-specific percentile charts of SitHt/Ht vs age were generated for NHB and for NHW and Mexican American youth combined.

CONCLUSIONS

SitHt/Ht assessment can detect disproportionate short stature in children with skeletal dysplasia, but age-, sex-, and population-specific reference charts are required to interpret this measurement. NHB children in the US have significantly lower SitHt/Ht than other children, which adds complexity to interpretation. We recommend the use of standardized ancestry-specific reference charts in screening for skeletal dysplasias and have developed such charts in this study.

Best practice guidelines for management of spinal disorders in skeletal dysplasia

BACKGROUND

Disorders of the spine present a common and difficult management concern in patients with skeletal dysplasia. Due to the rarity of these conditions however, the literature, largely consisting of small, single institution case series, is sparse in regard to well-designed studies to support clinical decision making in these situations.

METHODS

Using the Delphi method, an international, multi-disciplinary group of individuals, with significant experience in the care of patients with skeletal dysplasia, convened to develop multi-disciplinary, "best practice" guidelines in the care of spinal disorders in patients with skeletal dysplasia.

RESULTS

Starting with 33 statements, the group a developed a list of 31 "best practice" guidelines.

CONCLUSIONS

The guidelines are presented and discussed to provide context for clinicians in their decision making in this often-challenging realm of care.

Early-Onset Spinal Deformity in Skeletal Dysplasias: A Multicenter Study of Growth-Friendly Systems

PURPOSE

Severe, early-onset spinal deformity is common in patients with skeletal dysplasia. These deformities often present at young ages and are associated with significant pulmonary dysfunction. The objective of this study is to verify the effectiveness of growth-friendly spinal instrumentation systems in promoting growth in patients with skeletal dysplasia and early-onset kyphoscoliosis.

METHODS

A retrospective, multicenter comparative cohort study was performed. Twenty-three patients identified to have a skeletal dysplasia (SKD) were evaluated for diagnosis, age at treatment, gender, and type of growing rod construct (spine vs. rib constructs). Patients were matched by age and construct type with similarly treated patients with early-onset scoliosis (CON) without skeletal dysplasia. Radiographic parameters including maximum coronal and sagittal Cobb angle with levels, T1-S1 height, and T1-T12 height were measured.

RESULTS

T1-T12 (12.8 vs. 15.2 cm, p = .01) and T1-S1 (21.2 vs. 24.5 cm, p = .05) heights were significantly shorter for the SKD group at implantation, and kyphosis tended to be more severe in children with SKD (p = .80 and .07, respectively). Kyphosis did not improve with treatment. Scoliosis improved (p < .01), and ΔT1-T12 and ΔT1-S1 significantly increased in both groups (p < .01). Complication rates were similar between the two groups; however, patients with SKD had more intraoperative monitoring changes and hardware failures (p < .005).

CONCLUSION

Although patients with SKD start with shorter spine lengths, gains in spine length appear to be comparable to other forms of EOS. Neuromonitoring changes and implant failures are more common in the SKD group.

SIGNIFICANCE

The effectiveness of growth-friendly techniques in promoting growth in early-onset spinal deformities in patients with skeletal dysplasia has not been previously studied. We report the first comprehensive review of this topic. Growth-friendly techniques are an appropriate treatment option in this patient population.

An infantile alantoaxial dislocation with patent foramen ovale managed with titanium cabling and allogenic bone grafts

Atlantoaxial dislocation is a disorder that is characterized with loss of stability of the atlas and axis (C1-C2) with consequential loss of usual articulation. Although this condition is very common, no one has reported a case as young as our patients. We present a 7-month infant with bilateral paralysis of the lower limbs for four (4) months with no history of trauma. Computer tomographic (CT-scan) imaging revealed alantoaxial dislocation with severe cervical spinal cord compression. The odontoid process is displaced outwardly with no bone destruction. Doppler echocardiogram done revealed patent foramen ovale. Thorough physical examination as well as radiological evaluation revealed no feather malformations. Electrophysio - logical studies reveal normal compound muscle action potentials (CMAP) and sensory nerve action potentials (SNAPs) in all the limbs. Electromyography (EMG) also revealed normal nerves in the limbs and the trunk. We attained a stable fusion and anatomical reduction using a posterior titanium wire and an iliac bone graft harvested from his mother. This is the youngest patient reported in literature. Infantile alantoaxial dislocation should be managed at early stage to prevent long-term neurologic disorders.

Unilateral fixation for treatment of occipitocervical instability in children with congenital vertebral anomalies of the craniocervical junction

OBJECT Patients with occipitocervical (OC) instability from congenital vertebral anomalies (CVAs) of the craniocervical junction (CCJ) often have bony abnormalities that make instrumentation placement difficult. Within this patient population, some bilateral instrumentation constructs either fail or are not feasible, and a unilateral construct must be used. The authors describe the surgical management and outcomes of this disorder in patients in whom unilateral fixation constructs were used to treat OC instability. METHODS From a database of OC fusion procedures, the authors identified patients who underwent unilateral fixation for the management of OC instability. Patient characteristics, surgical details, and radiographic outcomes were reviewed. In each patient, CT scans were performed at least 4 months after surgery to evaluate for fusion. RESULTS Eight patients with CVAs of the CCJ underwent unilateral fixation for the treatment of OC instability. For 4 patients, the procedure occurred after a bilateral OC construct failed or infection forced hardware removal. For the remainder, it was the primary procedure. Two patients required reoperation for hardware revision and 1 developed nonunion requiring revision of the bone graft. Ultimately, 7 patients demonstrated osseous fusion on CT scans and 1 had a stable fibrous union. CONCLUSIONS These findings demonstrate that a unilateral OC fixation is effective for the treatment of OC instability in children with CVAs of the CCJ in whom bilateral screw placement fails or is not feasible.

Avoiding early complications and reoperation during occipitocervical fusion in pediatric patients

OBJECT

Surgical arthrodesis for pediatric occipitocervical (OC) instability has a high rate of success in a wide variety of challenging circumstances; however, identifying potential risk factors can help to target variables that should be the focus of improvement. The aim of this paper was to examine risk factors predictive of failure in a population of patients who underwent instrumented OC arthrodesis using a uniform surgical philosophy.

METHODS

The authors conducted a retrospective cohort study of pediatric patients who underwent OC fusion from 2001 to 2013 at a single institution to determine risk factors for surgical failure, defined as reoperation for revision of the arthrodesis or instrumentation. The primary study outcome was either radiographic confirmation of successful OC fusion or surgical failure requiring revision of the arthrodesis or instrumentation. The secondary outcome was the underlying cause of failure (hardware failure, graft failure, or infection). Univariate analysis was performed to assess the association between outcome and patient demographics, cause of OC instability, type of OC instrumentation, bone graft material, biological adjuncts, and complications.

RESULTS

Of the 127 procedures included, 20 (15.7%) involved some form of surgical failure and required revision surgery. Univariate analysis revealed that patients with deep wound infections requiring debridement were more likely to require surgical revision of the hardware or graft (p = 0.002). Subgroup analysis revealed that patients with skeletal dysplasia or congenital spinal anomalies were more likely to develop hardware failure than patients with other causes of OC instability (p = 0.020). Surgical failure was not associated with the method of C-2 fixation, type of rigid OC instrumentation, bone graft material, use of bone morphogenetic protein or biological adjuncts, cause of instability, sex, age, or having previous OC fusion operations.

CONCLUSIONS

Pediatric patients in the present cohort with postoperative wound infections requiring surgical debridement had higher surgical failure rates after OC fusion. Those with skeletal dysplasia and congenital spinal anomalies were more likely to require reoperation for hardware failure. Better understanding of the mode of surgical failure may enable surgeons to develop strategies to decrease the need for reoperation in pediatric patients with OC instability.

A review of the diagnosis and treatment of atlantoaxial dislocations

Study Design Literature review. Objective Atlantoaxial dislocation (AAD) is a rare and potentially fatal disturbance to the normal occipital-cervical anatomy that affects some populations disproportionately, which may cause permanent neurologic deficits or sagittal deformity if not treated in a timely and appropriate manner. Currently, there is a lack of consensus among surgeons on the best approach to diagnose, characterize, and treat this condition. The objective of this review is to provide a comprehensive review of the literature to identify timely and effective diagnostic techniques and treatment modalities of AAD. Methods This review examined all articles published concerning "atlantoaxial dislocation" or "atlantoaxial subluxation" on the PubMed database. We included 112 articles published between 1966 and 2014. Results Results of these studies are summarized primarily as defining AAD, the normal anatomy, etiology of dislocation, clinical presentation, diagnostic techniques, classification, and recommendations for timely treatment modalities. Conclusions The Wang Classification System provides a practical means to diagnose and treat AAD. However, future research is required to identify the most salient intervention component or combination of components that lead to the best outcomes.

Growth-sparing spinal instrumentation in skeletal dysplasia

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To report the outcomes of distraction-based, growth-sparing spinal instrumentation in patients with skeletal dysplasia.

SUMMARY OF BACKGROUND DATA

Patients with skeletal dysplasia with spinal deformity often undergo early fusion, further compromising an already small chest. Nonfusion techniques may provide a safe alternative and allow for thoracic growth.

METHODS

Between 2004 and 2010, 12 children with a diagnosis of various types of skeletal dysplasia underwent growth-sparing spinal instrumentation for severe spinal deformities. The mean duration of treatment with growing rods was 57 months (42-84 mo). Nine patients were treated with growing rods (8 dual, 1 single), and 3 were treated with vertical expandable prosthetic titanium rib (VEPTR; Synthes). Preoperative, initial postoperative, and final follow-up anteroposterior and lateral spine radiographs were measured for magnitude of deformity, junctional kyphosis, and implant failure.

RESULTS

The major curve Cobb angle improved from a mean of 79° preoperatively to a mean of 41° at the last follow-up (52%). There was a decrease in mean thoracic kyphosis from 77° preoperatively to 64° at final follow-up and an increase in mean lumbar lordosis from 58° preoperatively to 63° at final follow-up. The mean space available for the lungs increased by 26 mm on the concave and 24 mm on the convex side. Six patients required revision surgery for proximal junctional kyphosis. There were 4 rod failures and 6 hook and 8 screw dislodgements. One patient with vertical expandable prosthetic titanium rib had failed rib fixation that required revision.

CONCLUSION

Growth-sparing spinal instrumentation in patients with skeletal dysplasia and severe spinal deformity has a high complication and revision rate, and surgeons should closely monitor these patients. The complication rate is comparable with previous reports on patients with other diagnoses. However, deformities were well controlled, some trunk growth was achieved, and fusion surgery was delayed in all cases.

LEVEL OF EVIDENCE

4.

Recent progress in osteogenesis imperfecta

Osteogenesis imperfecta (OI), a rare clinical disease with abnormal type I collagen, is inherited or caused by mutation. A classification of OI into four types was proposed in 1979 and has been used up until four new types were added recently. A tough clinical challenge, OI causes abnormal blood coagulation and cardiovascular structure, airways obstruction, and delayed wound healing. The authors of the current article have reviewed recent progress in OI worldwide, including the mechanisms, classification, detection, clinical difficulties, and treatment.

Osteogenesis imperfecta: questions and answers

PURPOSE OF REVIEW

Considerable attention has recently been focused on the pathogenesis, diagnosis and treatment of osteogenesis imperfecta. Two new genes have been defined in patients with recessive severe or lethal osteogenesis imperfecta types. Diagnostic concerns involve testing procedures, either skin biopsies or DNA analysis. Bisphosphonates have been accepted as 'standard of care' for children with osteogenesis imperfecta. However, questions remain as to the selection of patients for treatment, effectiveness in fracture prevention, which bisphosphonates should be used and the duration of treatment. Orthopedic intervention occurs on several levels: including the immediate treatment of fractures, the treatment of scoliosis and the use of intramedullary rods.

RECENT FINDINGS

The discovery of mutations involving CRTAP and LEPRE1 genes in severe/lethal and recessively inherited osteogenesis imperfecta has provided partial answers to questions about 'other' osteogenesis imperfecta genes in patients with an osteogenesis imperfecta phenotype but no COL1A1 and COL1A2 mutations. Current experience suggests that DNA analysis is a better test for diagnosis as compared with dermal biopsy. There are no standardized guidelines for initiating bisphosphonate treatment in children. Recent data suggest either intravenous or oral bisphosphonates are effective, but differences exist between different bisphosphonates. Two recent reports document the paucity of evidence-based data regarding the effectiveness of bisphosphonate treatment in fracture prevention.

SUMMARY

This report will update the medical and orthopedic approaches to care for children with osteogenesis imperfecta.