Chiari I malformation associated with syringomyelia and scoliosis: a twenty-year review of surgical and nonsurgical treatment in a pediatric population

Role of spinal MRI for pre-operative work up in patients with adolescent idiopathic scoliosis: a retrospective case study and narrative review

INTRODUCTION

There remains variability in the acquisition of whole-spine MRI prior to surgical correction in patients with adolescent idiopathic scoliosis (AIS). In this study, we take a retrospective look at the clinical impact of uniformly obtaining spinal MRI on all patients with a diagnosis of AIS.

METHODS

Three hundred thirty four patients with presumed AIS who underwent surgery between 2017 and 2022 were identified; 283 of these patients who were asymptomatic and had a preoperative MRI in the database were included. We investigated radiographic, demographic, and clinical risk factors for the presence of neural axis anomalies. Radiologists' reports were reviewed to determine the level of the conus medullaris and the presence of any intra-spinal dysraphisms. The utility of known risk factors for neural axis anomalies and the utility of MRI identifying anomalies on clinical decision-making, intra-operative neuromonitoring (IONM) alerts, and postoperative neurologic insult in asymptomatic AIS patients were investigated.

RESULTS

There were 283 patients with a mean age of 14.1 years, 67 males (22.6%) and 26 (9.2%) left-sided thoracic curves. MRI identified nine patients with central cord dilations, four patients with low cerebellar tonsils, four patients with Chiari Malformations, five patients with low-lying conus, one patient with a tethered cord, and five patients with arachnoid cysts. Six (2.1%) of the 283 patients underwent a neurosurgical intervention and 3 (50%) of the 6 went on to have IONM alerts. Eighteen (6.4%) of the 283 patients had IONM alerts and 5 (28%) of the 18 had neural axis anomalies. None of the patients with IONM alerts had a permanent neurologic deficit post-operatively.

CONCLUSION

In asymptomatic patients presumed to have AIS, 9.9% had a neuro-axis anomaly, 2.1% needed a neurosurgical intervention, and 6.4% of the patients had an IONM alert. We did not find known risk factors for identifying neural axis anomalies to have statistically significant application in asymptomatic AIS patients. Presence of neuroaxis anomalies increased the chance of having IONM alerts, however, we were unable to demonstrate if neurosurgical interventions in these patients with anomalies were preventative for IONM alerts or have statistically significant protection against clinical complications.

Magnetic resonance imaging evaluation of the cerebellar tonsil position before and after posterior spinal fusion in adolescent idiopathic scoliosis

BACKGROUND

Chiari malformation type I(CM-I) is one of the most common neurological malformations observed in patients with adolescent idiopathic scoliosis (AIS). It remains uncertain whether AIS patients without neurological symptoms require CM-I decompression before undergoing spinal corrective surgery to prevent cerebellar tonsil herniation and potential neurological complications. This study aims to assess variations in the position of the cerebellar tonsil after posterior spinal fusion (PSF) in neurologically intact patients with AIS.

METHODS

We retrospectively evaluated 40 patients with AIS who underwent posterior spinal fusion (PSF) without neurological symptoms. Sagittal hindbrain MRIs were performed before and after spinal surgery. The cerebellar tonsil's position relative to the foramen magnum was measured using the method described by Aboulezz (J Comput Assist Tomogr 1985). We assessed variations in the cerebellar tonsil position concerning spinal correction and elongation after PSF.

RESULTS

The average preoperative magnitude of the scoliotic curve was 53.15 degrees (SD 10.46 degrees), and that of thoracic kyphosis was 35.42 degrees (SD 12.38 degrees). In the immediate postoperative period, the average magnitudes were 7.45 degrees (SD 7.33 degrees) and 27.87 degrees (SD 9.03 degrees), respectively. The average correction achieved with PSF was 86% in the coronal plane (p < 0.00001). The average length of the spine in the coronal plane was 44.5 cm (SD 5.25 cm) preoperatively and 48.27 cm (SD 4.40 cm) postoperatively (p < 0.00001). The average length of the vertebral column in the sagittal plane was 50.87 cm (SD 4.47 cm) preoperatively and 55.13 cm (SD 3.27 cm) postoperatively (p < 0.00001). No significant difference was observed in the position of the cerebellar tonsil in the measurements taken before and after spinal deformity correction (p = 0.6042). In 10 out of 40 patients, caudal displacement of the cerebellar tonsil was observed after PSF. In 28 patients, no variation in the position of the cerebellar tonsil was observed, and in 2, cephalic displacement was noted.

CONCLUSION

In AIS patients with a normal position of the cerebellar tonsil undergoing posterior spinal fusion, there is no significant change in their position after surgery. Our analysis did not reveal any correlation between curve correction, spine elongation, and variations in the cerebellar tonsil position.

SIGNIFICANCE

The position of the cerebellar tonsil remained largely unchanged after PSF in AIS patients without neurological symptoms. Further studies would be necessary to determine whether surgical decompression is required in asymptomatic patients with CM-I before undergoing surgery to correct spinal deformity.

The Role of Neurophysiology in Managing Patients with Chiari Malformations

Chiari malformation type 1 (CM1) includes various congenital anomalies that share ectopia of the cerebellar tonsils lower than the foramen magnum, in some cases associated with syringomyelia or hydrocephalus. CM1 can cause dysfunction of the brainstem, spinal cord, and cranial nerves. This functional alteration of the nervous system can be detected by various modalities of neurophysiological tests, such as brainstem auditory evoked potentials, somatosensory evoked potentials, motor evoked potentials, electromyography and nerve conduction studies of the cranial nerves and spinal roots, as well as brainstem reflexes. The main goal of this study is to review the findings of multimodal neurophysiological examinations in published studies of patients with CM1 and their indication in the diagnosis, treatment, and follow-up of these patients, as well as their utility in intraoperative monitoring.

Pediatric Aerodigestive Medicine: Advancing Collaborative Care for Children With Oropharyngeal Dysphagia

OBJECTIVES

Aerodigestive disorders encompass various pathological conditions affecting the lungs, upper airway, and gastrointestinal tract in children. While advanced care has primarily occurred in specialty centers, many children first present to general pediatric gastroenterologists with aerodigestive symptoms necessitating awareness of these conditions. At the 2021 Annual North American Society for Pediatric Gastroenterology, Hepatology and Nutrition meeting, the aerodigestive Special Interest Group held a full-day symposium entitled, Pediatric Aerodigestive Medicine: Advancing Collaborative Care of Children with Aerodigestive Disorders. The symposium aimed to underline the significance of a multidisciplinary approach to achieve better outcomes for these complex patients.

METHODS

The symposium brought together leading experts to highlight the growing aerodigestive field, promote new scientific and therapeutic strategies, share the structure and benefits of a multidisciplinary approach in diagnosing common and rare aerodigestive disorders, and foster multidisciplinary discussion of complex cases while highlighting the range of therapeutic and diagnostic options. In this article, we showcase the diagnostic and therapeutic approach to oropharyngeal dysphagia (OPD), one of the most common aerodigestive conditions, emphasizing the role of a collaborative model.

CONCLUSIONS

The aerodigestive field has made significant progress and continues to grow due to a unique multidisciplinary, collaborative model of care for these conditions. Despite diagnostic and therapeutic challenges, the multidisciplinary approach has enabled and greatly improved efficient, high-quality, and evidence-based care for patients, including those with OPD.

Predictors of reoperation for spinal disorders in Chiari malformation patients with prior surgical decompression

Background

Chiari malformation (CM) is a cluster of related developmental anomalies of the posterior fossa ranging from asymptomatic to fatal. Cranial and spinal decompression can help alleviate symptoms of increased cerebrospinal fluid pressure and correct spinal deformity. As surgical intervention for CM increases in frequency, understanding predictors of reoperation may help optimize neurosurgical planning.

Materials and Methods

This was a retrospective analysis of the prospectively collected Healthcare Cost and Utilization Project's California State Inpatient Database years 2004-2011. Chiari malformation Types 1-4 (queried with ICD-9 CM codes) with associated spinal pathologies undergoing stand-alone spinal decompression (queried with ICD-9 CM procedure codes) were included. Cranial decompressions were excluded.

Results

One thousand four hundred and forty-six patients (29.28 years, 55.6% of females) were included. Fifty-eight patients (4.01%) required reoperation (67 reoperations). Patients aged 40-50 years had the most reoperations (11); however, patients aged 15-20 years had a significantly higher reoperation rate than all other groups (15.5% vs. 8.2%, P = 0.048). Female gender was significantly associated with reoperation (67.2% vs. 55.6%, P = 0.006). Medical comorbidities associated with reoperation included chronic lung disease (19% vs. 6.9%, P < 0.001), iron deficiency anemia (10.3% vs. 4.1%, P = 0.024), and renal failure (3.4% vs. 0.9%, P = 0.05). Associated significant cluster anomalies included spina bifida (48.3% vs. 34.8%, P = 0.035), tethered cord syndrome (6.9% vs. 2.1%, P = 0.015), syringomyelia (12.1% vs. 5.9%, P = 0.054), hydrocephalus (37.9% vs. 17.7%, P < 0.001), scoliosis (13.8% vs. 6.4%, P = 0.028), and ventricular septal defect (6.9% vs. 2.3%, P = 0.026).

Conclusions

Multiple medical and CM-specific comorbidities were associated with reoperation. Addressing them, where possible, may aid in improving CM surgery outcomes.

The Chiari Malformations: A Bibliometric Analysis of the 100 Most Cited Articles

OBJECTIVE

The Chiari malformations present heterogeneous entities, raising many questions regarding their natural history, pathophysiology, treatment options, and prognosis. Bibliometric analyses have emerged as a method to assess the impact of articles in current clinical practice.

METHODS

The most cited articles were identified via Scopus Library by using the keywords "Chiari," "Arnold-Chiari," and "Chiari malformation." The 100 most cited articles were then assembled and analyzed in detail.

RESULTS

The top 100 articles yielded a mean of 155,28 citations per article, ranging from 87 to 896 citations, and from 1.63 to 38.96 per year. Years of publications ranged from 1950 to 2015. Oakes was the most cited author (n = 7), followed by Tubbs and Milhorat. The country with the highest cited articles was the United States (n = 63), followed by the United Kingdom (n = 6), Italy (n = 5), Spain (n = 5), Japan (n = 4), and Germany (n = 3). Neurosurgery is the journal with the most highly cited articles (n = 21), followed by Journal of Neurosurgery (n = 19). Most articles focused on Chiari malformation type I (n = 83). The topic discussed most often was imaging (n = 63), followed by the evaluation of treatment outcome (n = 58), clinical signs and symptoms (n = 57), and the role of surgery (n = 56).

CONCLUSIONS

The present bibliometric analysis provides a succinct appraisal of the most cited articles concerning Chiari malformation, allowing a deeper insight in this area and its main influential articles with their impact on current clinical practice and future research.

Treatment of Chiari Malformation and Concomitant Paediatric Scoliosis Long-Term Follow-Up in One Major Referral Centre in the UK

OBJECTIVE

Paediatric scoliosis (PS) and Chiari malformation type 1 (CM-1) have been reported to be associated with each other. Scoliosis curvature is a common finding among patients operated for CM-1, and curve development has been related to it. We report a cohort of PS and CM-1 patients managed with posterior fossa and upper cervical decompression (PFUCD) by a single surgeon, with an average of two years of follow-up.

METHODS

We present a retrospective cohort in a single referral centre for patients with CM-1 and PS.

RESULTS

From 2011 to 2018, we identified fifteen patients with CM-1 and PS; eleven underwent PFUCD, ten had symptomatic CM-1, and one had asymptomatic CM-1 but showed curve progression. The remaining four CM-1 patients were asymptomatic and were hence treated conservatively. The average follow-up post-PFUCD was 26.2 months. Scoliosis surgery was performed in seven cases; six patients underwent PFUCD prior to the scoliosis correction. One scoliosis case underwent surgery in the presence of mild CM-1 treated conservatively. The remaining four cases were scheduled for scoliosis correction surgery, while three were managed conservatively, with one case lost to follow-up. The average time between PFUCD and scoliosis surgery was 11 months. None of the cases had intraoperative neuromonitoring alerts or perioperative neurological complications.

CONCLUSION

CM-1 with concomitant scoliosis can be found. Symptomatic CM-1 might require surgery, but as we discovered, PFUCD had negligible effect on curve progression and the future need for scoliosis surgery.

Effectiveness of C1 Laminectomy for Chiari Malformation Type 1: Posterior Fossa Volume Expansion and Syrinx-Volume Decrease Rate

PURPOSE

This study aimed to analyze the effect of foramen magnum decompression with C1 laminectomy (C1L) for Chiari malformation type 1 (CM-1) in terms of improving clinical symptoms, expanding posterior fossa volume, and decreasing syrinx volume.

MATERIALS AND METHODS

Between January 2007 and June 2019, 107 patients with CM-1 were included. The median patient age was 13±13 years (range: 9 months-60 years), female-to-male ratio was 1:1, and average length of tonsil herniation was 13±5 mm (range: 5-24 mm). Surgical techniques were divided into four groups based on duraplasty or C1L usage. Among the study subjects, 38 patients underwent duraplasty and had their syrinx volumes measured separately on serial magnetic resonance imaging. A three-dimensional visualization software was used to evaluate the syrinx-volume decrease rate.

RESULTS

Bony decompression exhibited a mere 20% volume expansion of the lower-half posterior fossa. C1L offered a 3% additional volume expansion, which rose to 5% when duraplasty was added (p=0.029). There were no significant differences in complication rate when C1L was combined with duraplasty (p=0.526). Syrinx volumes were analyzed in 38 patients who had undergone duraplasty. Among them, 28 patients who had undergone duraplasty without C1L demonstrated a 5.9% monthly decrease in syrinx volume, which was 7.5% in the remaining 10 patients with C1L (p=0.040).

CONCLUSION

C1L was effective in increasing posterior fossa volume expansion, both with and without duraplasty. A more rapid decrease in syrinx volume occurred when C1L was combined with duraplasty.

Chiari Type 1 Malformation and Syringomyelia in Children: Classification and Treatment Options

Chiari type 1 malformation (CIM) is defined as tonsillar ectopia of >5 mm, while syringomyelia (SM) is defined as a cerebrospinal fluid (CSF)-filled cavity larger than 3 mm dissecting the spinal cord. Over the last decades, our understanding of these pathologies has grown; however, many controversies still exist almost in every aspect of CIM and SM, including etiology, indication for treatment, timing of treatment, surgical technique, follow-up regime, and outcome. This chapter provides a comprehensive overview on different aspects of CIM and SM and on the still existing controversies, based on the evidence presently available. Future directions for clinical research concerning CIM and SM treatment and outcome are elaborated and discussed as well.

The use of MRI in the study of patients with idiopathic scoliosis: a systematic review of the literature

Objective. To analyze the frequency of hidden neuraxial pathology in idiopathic scoliosis (IS), to substantiate the need for MRI in IS and to identify promising areas for the use of MRI in the examination of patients with IS.Material and Methods. The literature review was carried out using the PubMed and Google Scholar databases. Of the 780 papers on the research topic, 65 were selected after removing duplicates and checking for inclusion/exclusion criteria. As a result, 49 original studies were included in the analysis. Level of evidence – II.Results. According to modern literature, the main direction of using MRI in idiopathic scoliosis is the search for predictors of latent pathology of the spinal cord and craniovertebral junction. The frequency of neuraxial pathology in idiopathic scoliosis is 8 % for adolescent IS and 16 % for early IS. The main predictors of neuraxial pathology are male sex, early age of deformity onset, left-sided thoracic curve and thoracic hyperkyphosis. MRI in IS may be a useful addition to radiological diagnostic methods to identify risk factors and to study degenerative changes in the spine.Conclusion. MRI of the spine should be performed in the early stages of IS to detect latent spinal cord tethering. In type I Chiari anomalies, there is a possibility that early neurosurgery can prevent the development of scoliosis. The main signs of latent neuraxial pathology in IS are early progression of spinal deformity, left-sided thoracic curve, male gender and thoracic kyphosis over 40° according to Cobb.MRI can be used as an effective non-invasive tool in research aimed at identifying risk factors for IS, including helping to track early degeneration of intervertebral discs.

Preoperative MRI and Intraoperative Monitoring Differentially Prevent Neurological Sequelae in Idiopathic Scoliosis Surgical Correction, While Curves >70 Degrees Increase the Risk of Neurophysiological Incidences

The aim was to investigate the role of preoperative magnetic resonance imaging (MRI) and intraoperative monitoring (IOM) in the prevention of correction-related complications in idiopathic scoliosis (IS). We conducted a retrospective case study of 129 patients with juvenile and adolescent IS. The operations took place between 2005 and 2018 in Uppsala University Hospital. Data from MRI scans and IOM were collected. The patients were divided into groups depending on Lenke’s classification, sex, major curve (MC) size, and onset age. Neurophysiological incidences were reported in ten patients (7.8%), while nine of them had no signs of intraspinal pathology. Six patients (4.7%) had transient incidences; however, in four patients (3.1%), an intervention was required for the normalization of action potentials. Three of them had an MC >70 degrees, which was significantly higher than the expected value. Eight patients (6.1%) had intraspinal pathologies, and two of them (1.5%) underwent decompression. We suggest the continuation of MRI screening preoperatively and, most importantly, the use of IOM. In three cases with no signs of pathology in the MRI, IOM prevented possible neurological injuries. MCs >70 degrees should be considered a risk factor for the occurrence of neurophysiological deficiencies that require action to be normalized.

Headache characteristics and postoperative course in Chiari I malformation

Background

Chiari I malformation typically presents with cough headache. However, migraine-like or tension-type-like headaches may also occur. There are limited publications on Chiari I malformation-associated headache semiologies and the effect of foramen magnum decompression on different headache types.

Methods

A retrospective analysis complemented by structured phone interviews was performed on 65 patients with Chiari I malformation, treated at our hospital between 2010 and 2021. Headache semiology (according to ICHD-3), frequency, intensity, and radiological characteristics were evaluated pre- and postoperatively.

Results

We included 65 patients. 38 patients were female and 27 male. Mean age was 43.9 ± 15.7 years. Headache was predominant in 41 patients (63.0%). Twenty-one patients had cough headache and 20 had atypical headache (12 migrainous, eight tension-type headache-like). Thirty-five patients with headache underwent surgery. Frequency, intensity, and analgesic use was significantly reduced in cough headache (p < 0.001). Atypical headaches improved less (p = 0.004 to 0.176). Exploratory analysis suggested that larger preoperative tonsillar descent correlated with larger postoperative headache intensity relief (p = 0.025).

Conclusion

Decompression was effective in Chiari I malformation-related cough headache. Atypical headache responded less well, and the causal relation with Chiari I malformation remains uncertain. For atypical headache, decompression should only be considered after failed appropriate preventive therapy and within an interdisciplinary approach involving a neurologist.

Socioeconomic and demographic factors in the diagnosis and treatment of Chiari malformation type I and syringomyelia

OBJECTIVE

The goal of this study was to assess the social determinants that influence access and outcomes for pediatric neurosurgical care for patients with Chiari malformation type I (CM-I) and syringomyelia (SM).

METHODS

The authors used retro- and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM-I and SM who received surgical treatment and had at least 1 year of follow-up data. Race, ethnicity, and insurance status were used as comparators for preoperative, treatment, and postoperative characteristics and outcomes.

RESULTS

A total of 637 patients met inclusion criteria, and race or ethnicity data were available for 603 (94.7%) patients. A total of 463 (76.8%) were non-Hispanic White (NHW) and 140 (23.2%) were non-White. The non-White patients were older at diagnosis (p = 0.002) and were more likely to have an individualized education plan (p < 0.01). More non-White than NHW patients presented with cerebellar and cranial nerve deficits (i.e., gait ataxia [p = 0.028], nystagmus [p = 0.002], dysconjugate gaze [p = 0.03], hearing loss [p = 0.003], gait instability [p = 0.003], tremor [p = 0.021], or dysmetria [p < 0.001]). Non-White patients had higher rates of skull malformation (p = 0.004), platybasia (p = 0.002), and basilar invagination (p = 0.036). Non-White patients were more likely to be treated at low-volume centers than at high-volume centers (38.7% vs 15.2%; p < 0.01). Non-White patients were older at the time of surgery (p = 0.001) and had longer operative times (p < 0.001), higher estimated blood loss (p < 0.001), and a longer hospital stay (p = 0.04). There were no major group differences in terms of treatments performed or complications. The majority of subjects used private insurance (440, 71.5%), whereas 175 (28.5%) were using Medicaid or self-pay. Private insurance was used in 42.2% of non-White patients compared to 79.8% of NHW patients (p < 0.01). There were no major differences in presentation, treatment, or outcome between insurance groups. In multivariate modeling, non-White patients were more likely to present at an older age after controlling for sex and insurance status (p < 0.01). Non-White and male patients had a longer duration of symptoms before reaching diagnosis (p = 0.033 and 0.004, respectively).

CONCLUSIONS

Socioeconomic and demographic factors appear to influence the presentation and management of patients with CM-I and SM. Race is associated with age and timing of diagnosis as well as operating room time, estimated blood loss, and length of hospital stay. This exploration of socioeconomic and demographic barriers to care will be useful in understanding how to improve access to pediatric neurosurgical care for patients with CM-I and SM.

Longitudinal scoliosis behavior in Chiari malformation with and without syringomyelia

OBJECTIVE

The objective of this study was to understand the natural history of scoliosis in patients with Chiari malformation type I (CM-I) with and without syringomyelia.

METHODS

A retrospective review of data was conducted. Patients with CM-I were identified from a cohort of 14,118 individuals age 18 years or younger who had undergone MRI over an 11-year period at the University of Michigan. Patients eligible for study inclusion had a coronal curve ≥ 10° on radiography, associated CM-I with or without syringomyelia, and at least 1 year of clinical follow-up prior to any surgery. Curve magnitude at initial diagnosis, prior to posterior fossa decompression (PFD; if applicable), and at the last follow-up (prior to any surgical correction of scoliosis) was recorded, and clinical and radiographic characteristics were noted. The change in curve magnitude by 10° was defined as curve progression (increase by 10°) or regression (decrease by 10°).

RESULTS

Forty-three patients met the study inclusion criteria and were analyzed. About one-third (35%) of the patients presented with symptoms attributed to their CM-I. The mean degree of scoliosis at presentation was 32.6° ± 17.7°. Twenty-one patients (49%) had an associated syrinx. The mean tonsil position below the level of the foramen magnum was 9.8 ± 5.8 mm. Patients with a syrinx were more likely to have a curve > 20° (86% vs 41%, p = 0.002). Curve magnitude remained stable (≤ ±10°) in 77% of patients (33/43), progressed in 16% (7/43), and regressed in 7% (3/43). Mean age was higher (14.8 ± 0.59 years) among patients with regressed curves (p = 0.026). All regressed curves initially measured ≤ 20° (mean 14° ± 5.3°), and none of the patients with regressed curves had a syrinx. The change in curve magnitude was statistically similar in patients with (7.32° ± 17.7°) and without (5.32° ± 15.8°) a syrinx (p = 0.67). After a mean follow-up of 3.13 ± 2.04 years prior to surgery, 27 patients (63%) ultimately underwent posterior fossa or scoliosis correction surgery. For those who eventually underwent PFD only, the rate of change in curve magnitude prior to surgery was 0.054° ± 0.79°. The rate of change in curve magnitude was statistically similar before (0.054° ± 0.79°) and after (0.042° ± 0.33°) surgery (p = 0.45) for patients who underwent PFD surgery only.

CONCLUSIONS

The natural history of scoliosis in the presence of CM-I is variable, though most curves remained stable. All curves that regressed were ≤ 20° at initial diagnosis, and most patients in such cases were older at scoliosis diagnosis. Patients who underwent no surgery or PFD only had similar profiles for the change in curve magnitude, which remained relatively stable overall, as compared to patients who underwent PFD and subsequent fusion, who demonstrated curve progression. Among the patients with a syrinx, no curves regressed, most remained stable, and some progressed. Understanding this variability is a first step toward building a prediction model for outcomes for these patients.

Chiari 1: Is decompression always necessary previous to scoliosis surgery?

The association between Chiari 1 malformation and scoliosis is well known in the literature. Prevalence has increased after the advent of magnetic resonance imaging. In children with this association, prophylactic suboccipital decompression prior to scoliosis correction is a common surgical procedure although the rationale for this surgical management and whether not performing it may lead to spinal cord injury has not been clearly elucidated. We conducted a systematic review of the literature with the aim to obtain strong data to support the hypothesis that it is safe to proceed with scoliosis correction without prior prophylactic suboccipital decompression for Chiari 1 in an asymptomatic population. Using the Prisma methodology, we analyzed 3250 studies published between 1972 and 2018. Only four studies met the inclusion criteria. None of the studies had a level of evidence high enough to recommend prophylactic decompression previous to correction of the spinal deformity.

Syringomyelia: diagnosis and management

In the pre-MR era syringomyelia often presented late, as a crippling neurological disorder. Today, most cases are diagnosed earlier, with less pronounced deficits. We are therefore presented with new challenges, including understanding the significance of various presenting symptoms, knowing when surgery might help and being aware of other treatments that could benefit someone living with the effects of syringomyelia, or its underlying cause.

Brace treatment for scoliosis secondary to chiari malformation type 1 or syringomyelia without neurosurgical intervention: A matched comparison with idiopathic scoliosis

PURPOSE

To evaluate the effectiveness of brace treatment in patients with Chiari malformation type 1 (CM-1) or syringomyelia associated scoliosis without neurosurgical intervention.

METHODS

This was a retrospective case-control study. 34 CM-1 or syringomyelia (CMS) patients who received brace treatment without neurosurgical intervention were recruited. Another 68 matched patients with idiopathic scoliosis who received bracing served as the control group. The matching criteria included gender, age (± 1 years), Risser sign (± 1 grade), initial curve magnitude (± 5°), curve patterns and follow-up time (± 6 months). Patients who encountered curve progression and scoliosis surgery were compared between different groups.

RESULTS

Until the last visit, 16 (47%) patients in CMS group and 18 (26%) patients in IS group occurred curve progression; 9 (26%) patients and 15 (22%) patients underwent scoliosis surgery, respectively. Compared to idiopathic scoliosis, patients with CMS-associated scoliosis had a significantly higher rate of curve progression (P = 0.038). However, no significant difference was observed between two groups regarding to the rate of surgery (P = 0.867). Patients with combined CM-1 and syringomyelia had a higher rate of surgery than patients with isolated CM-1 or syringomyelia (P = 0.049). The double major curve pattern was identified as the risk factor for curve progression.

CONCLUSION

Brace treatment is effective for CMS-associated scoliosis without neurosurgical intervention. Compared to idiopathic scoliosis, brace can provide similar prevention for scoliosis surgery in CMS patients, but slight or moderate curve progression may occur. Specifically, patients with combined CM-1 and syringomyelia should be followed closely with a higher expectation of curve progression.

Extradural decompression versus duraplasty in Chiari malformation type I with syrinx: outcomes on scoliosis from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is common in patients with Chiari malformation type I (CM-I)-associated syringomyelia. While it is known that treatment with posterior fossa decompression (PFD) may reduce the progression of scoliosis, it is unknown if decompression with duraplasty is superior to extradural decompression.

METHODS

A large multicenter retrospective and prospective registry of 1257 pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for patients with scoliosis who underwent PFD with or without duraplasty.

RESULTS

In total, 422 patients who underwent PFD had a clinical diagnosis of scoliosis. Of these patients, 346 underwent duraplasty, 51 received extradural decompression alone, and 25 were excluded because no data were available on the type of PFD. The mean clinical follow-up was 2.6 years. Overall, there was no difference in subsequent occurrence of fusion or proportion of patients with curve progression between those with and those without a duraplasty. However, after controlling for age, sex, preoperative curve magnitude, syrinx length, syrinx width, and holocord syrinx, extradural decompression was associated with curve progression > 10°, but not increased occurrence of fusion. Older age at PFD and larger preoperative curve magnitude were independently associated with subsequent occurrence of fusion. Greater syrinx reduction after PFD of either type was associated with decreased occurrence of fusion.

CONCLUSIONS

In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in subsequent occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with an extradural decompression. However, after controlling for preoperative factors including age, syrinx characteristics, and curve magnitude, patients treated with duraplasty were less likely to have curve progression than patients treated with extradural decompression. Further study is needed to evaluate the role of duraplasty in curve stabilization after PFD.

Radiological and clinical associations with scoliosis outcomes after posterior fossa decompression in patients with Chiari malformation and syrinx from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

In patients with Chiari malformation type I (CM-I) and a syrinx who also have scoliosis, clinical and radiological predictors of curve regression after posterior fossa decompression are not well known. Prior reports indicate that age younger than 10 years and a curve magnitude < 35° are favorable predictors of curve regression following surgery. The aim of this study was to determine baseline radiological factors, including craniocervical junction alignment, that might predict curve stability or improvement after posterior fossa decompression.

METHODS

A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and a syrinx (≥ 3 mm in width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°) in patients who underwent posterior fossa decompression and who also had follow-up imaging.

RESULTS

Of 825 patients with CM-I and a syrinx, 251 (30.4%) were noted to have scoliosis present at the time of diagnosis. Forty-one (16.3%) of these patients underwent posterior fossa decompression and had follow-up imaging to assess for scoliosis. Twenty-three patients (56%) were female, the mean age at time of CM-I decompression was 10.0 years, and the mean follow-up duration was 1.3 years. Nine patients (22%) had stable curves, 16 (39%) showed improvement (> 5°), and 16 (39%) displayed curve progression (> 5°) during the follow-up period. Younger age at the time of decompression was associated with improvement in curve magnitude; for those with curves of ≤ 35°, 17% of patients younger than 10 years of age had curve progression compared with 64% of those 10 years of age or older (p = 0.008). There was no difference by age for those with curves > 35°. Tonsil position, baseline syrinx dimensions, and change in syrinx size were not associated with the change in curve magnitude. There was no difference in progression after surgery in patients who were also treated with a brace compared to those who were not treated with a brace for scoliosis.

CONCLUSIONS

In this cohort of patients with CM-I, a syrinx, and scoliosis, younger age at the time of decompression was associated with improvement in curve magnitude following surgery, especially in patients younger than 10 years of age with curves of ≤ 35°. Baseline tonsil position, syrinx dimensions, frontooccipital horn ratio, and craniocervical junction morphology were not associated with changes in curve magnitude after surgery.

Factors associated with syrinx size in pediatric patients treated for Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Factors associated with syrinx size in pediatric patients undergoing posterior fossa decompression (PFD) or PFD with duraplasty (PFDD) for Chiari malformation type I (CM-I) with syringomyelia (SM; CM-I+SM) are not well established.

METHODS

Using the Park-Reeves Syringomyelia Research Consortium registry, the authors analyzed variables associated with syrinx radiological outcomes in patients (< 20 years old at the time of surgery) with CM-I+SM undergoing PFD or PFDD. Syrinx resolution was defined as an anteroposterior (AP) diameter of ≤ 2 mm or ≤ 3 mm or a reduction in AP diameter of ≥ 50%. Syrinx regression or progression was defined using 1) change in syrinx AP diameter (≥ 1 mm), or 2) change in syrinx length (craniocaudal, ≥ 1 vertebral level). Syrinx stability was defined as a < 1-mm change in syrinx AP diameter and no change in syrinx length.

RESULTS

The authors identified 380 patients with CM-I+SM who underwent PFD or PFDD. Cox proportional hazards modeling revealed younger age at surgery and PFDD as being independently associated with syrinx resolution, defined as a ≤ 2-mm or ≤ 3-mm AP diameter or ≥ 50% reduction in AP diameter. Radiological syrinx resolution was associated with improvement in headache (p < 0.005) and neck pain (p < 0.011) after PFD or PFDD. Next, PFDD (p = 0.005), scoliosis (p = 0.007), and syrinx location across multiple spinal segments (p = 0.001) were associated with syrinx diameter regression, whereas increased preoperative frontal-occipital horn ratio (FOHR; p = 0.007) and syrinx location spanning multiple spinal segments (p = 0.04) were associated with syrinx length regression. Scoliosis (HR 0.38 [95% CI 0.16-0.91], p = 0.03) and smaller syrinx diameter (5.82 ± 3.38 vs 7.86 ± 3.05 mm; HR 0.60 [95% CI 0.34-1.03], p = 0.002) were associated with syrinx diameter stability, whereas shorter preoperative syrinx length (5.75 ± 4.01 vs 9.65 ± 4.31 levels; HR 0.21 [95% CI 0.12-0.38], p = 0.0001) and smaller pB-C2 distance (6.86 ± 1.27 vs 7.18 ± 1.38 mm; HR 1.44 [95% CI 1.02-2.05], p = 0.04) were associated with syrinx length stability. Finally, younger age at surgery (8.19 ± 5.02 vs 10.29 ± 4.25 years; HR 1.89 [95% CI 1.31-3.04], p = 0.01) was associated with syrinx diameter progression, whereas increased postoperative syrinx diameter (6.73 ± 3.64 vs 3.97 ± 3.07 mm; HR 3.10 [95% CI 1.67-5.76], p = 0.003), was associated with syrinx length progression. PFD versus PFDD was not associated with syrinx progression or reoperation rate.

CONCLUSIONS

These data suggest that PFDD and age are independently associated with radiological syrinx improvement, although forthcoming results from the PFDD versus PFD randomized controlled trial (NCT02669836, clinicaltrials.gov) will best answer this question.

Chiari I malformations with syringomyelia: long-term results of neurosurgical decompression

STUDY DESIGN

Retrospective case series.

OBJECTIVES

The objective was to assess the long-term outcomes on scoliosis following Chiari-I (CM-I) decompression in patients with CM-I and syringomyelia (SM). A secondary objective was to identify risk factors of scoliosis progression.

BACKGROUND

The association between CM-I with SM and scoliosis is recognized, but it remains unclear if CM-I decompression alters the long-term evolution of scoliosis in patients with associated syringomyelia.

METHODS

A retrospective review of children with scoliosis, CM-I, and SM during 1997-2015 was performed. Congenital, syndromic, and neuromuscular scoliosis were excluded. Clinical and radiographic characteristics were recorded at presentation, pre-decompression, after 1-year, and latest follow-up. A scale to measure syringomyelia area on MRI was used to evaluate SM changes post-decompression.

RESULTS

65 children with CM-I, SM, and scoliosis and a mean age of 8.9 years (range 0.7-15.8) were identified. Mean follow-up was 6.9 years (range 2.0-20.4). Atypical curves were present in 28 (43%) children. Thirty-eight patients (58%) underwent decompression before 10 years. Syringomyelia size reduced a mean of 70% after decompression (p < 0.001). Scoliosis improved in 26 (40%), stabilized in 17 (26%), and progressed in 22 (34%) cases. Early spinal fusion was required in 7 (11%) patients after a mean of 0.5 ± 0.37 years and delayed fusion in 16 (25%) patients after 6.0 ± 3.24 years. The remaining 42 (65%) patients were followed for a median of 6.1 years (range 2.0-12.3) without spine instrumentation or fusion. Fusion patients experienced less improvement in curve magnitude 1-year post-decompression (p < 0.001) and had larger curves at presentation (43° vs. 34°; p = 0.004).

CONCLUSIONS

Syringomyelia size decreased by 70% after CM-I decompression and scoliosis stabilized or improved in two-thirds of patients. Greater curve improvement within the first year post-decompression and smaller curves at presentation decreased the risk of spinal fusion. Neurosurgical decompression is recommended in children with CM-I, SM, and scoliosis with the potential to treat all three conditions.

LEVEL OF EVIDENCE

Level IV.

Somatosensory and motor evoked potentials during correction surgery of scoliosis in neurologically asymptomatic Chiari malformation-associated scoliosis: A comparison with idiopathic scoliosis

OBJECTIVES

To analyze the somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) in neurologically asymptomatic Chiari malformation-associated scoliosis (CMS) patients with and without syringomyelia as compared with those in idiopathic scoliosis (IS) ones, and to identify whether the deformities have impacts on the neurophysiological monitoring.

PATIENTS AND METHODS

This study included neurologically asymptomatic CMS patients undergoing posterior correction surgery between January 2010 and January 2016. IS patients were involved as control group and a subgroup of age- and height-matched IS patients were selected. The age, standing height and Cobb angles of main curve were measured. The SEPs latency and amplitude, MEPs amplitude, and the rate of abnormal SEPs pathologic change were compared between CMS and IS patients using independent-sample t-test and Chi-square test.

RESULTS

Sixty CMS patients and 210 IS patients were included. There was no difference between CMS patients and IS or matched IS patients in SEPs latency and amplitude, MEPs amplitude or rate of abnormal SEPs (p > 0.05). Forty-eight CMS patients concurrent with syringomyelia were associated with higher Cobb angle of main curve and lower SEPs amplitude than those without syringomyelia (p < 0.05). No significant difference was found between CMS patients with and without syringomyelia in age, height, SEPs latency, MEPs amplitude or rate of abnormal SEPs (p > 0.05).

CONCLUSION

Neurologically asymptomatic CMS patients showed similar absolute values of neurophysiological monitoring with IS patients. The syringomyelia in CMS indicated more severe curvature and lower SEPs amplitude even after posterior fossa decompression.

Radiological and clinical predictors of scoliosis in patients with Chiari malformation type I and spinal cord syrinx from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors' goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis.

METHODS

A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°).

RESULTS

Based on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB-C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude.

CONCLUSIONS

Syrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.

Management opinions from different centers (Rio de Janeiro)

INTRODUCTION

The surgical treatment of Chiari type 1 (CM1) malformation is controversial and depends largely on the preference of the surgeon. The evolution of neuroimaging resulted in an increased number of asymptomatic patients incidentally diagnosed.

PURPOSE

To study retrospectively a population of 24 symptomatic patients with CM1 operated between 1999 and 2017 in which intraoperative ultrasonography (IOUS)-assisted posterior fossa-C1 decompression was used to decide whether the dura mater should be opened (CVD+) or not (CVD).

RESULTS

Most of the patients complained of headache or neck pain, 15 had hydrosyringomyelia and 14 had some spinal cord involvement. Patients were categorized in improved, unchanged, or worse according the preoperative signs and symptoms. Overall, 19 patients improved, 3 deteriorated, and 2 remained unchanged. Among these, 4 out 5 had syringohydromyelia.

CONCLUSIONS

IOUS-assisted posterior fossa-C1 decompression is our preferred option to treat CM1. Children submitted to intradural procedures, initially or subsequently, had increased postoperative complications. CSF fistula or pseudomeningocele was the major cause of complication. The final result seems to correlate with the preoperative neurological status.

Opinion for different centers: surgical experience with Chiari malformation type I in children at Xuanwu Hospital, China

PURPOSE

To evaluate the presenting symptoms, surgical strategy, and outcome in children with Chiari malformation type I (CM-I).

METHODS

The medical records of children who were diagnosed with CM-I under 14 years old and subsequently underwent surgery for CM-I between 2014 and 2018 were reviewed. The medical records for presentation, radiological image, surgical intervention, and outcome were evaluated.

RESULTS

Twelve children with CM-I and syringomyelia were included. All of the children were symptomatic. The most common presenting symptom was weakness, followed by scoliosis. All of them underwent posterior fossa decompression with/without duraplasty. Relief of preoperative pathologies and syringomyelia was experienced by all of them.

CONCLUSIONS

The presenting symptoms of CM-I in children may be neurological deficits and scoliosis, which have a relationship with syringomyelia. Early recognition and a tailored operative procedure of CM-I in children could lead to good outcomes. Additional therapies for syringomyelia and scoliosis could be avoided.

Management of Chiari I malformations: a paradigm in evolution

PURPOSE

Despite decades of experience and research, the etiology and management of Chiari I malformations (CM-I) continue to raise more questions than answers. Controversy abounds in every aspect of management, including the indications, timing, and type of surgery, as well as clinical and radiographic outcomes. This review aims to outline past experiences, consolidate current evidence, and recommend directions for the future management of the Chiari I malformation.

METHODS

A review of recent literature on the management of CM-I in pediatric patients is presented, along with our experience in managing 1073 patients who were diagnosed with CM-I over the past two decades (1998-2018) at Children's National Medical Center (CNMC) in Washington DC.

RESULTS

The general trend reveals an increase in the diagnosis of CM-I at younger ages with a significant proportion of these being incidental findings (0.5-3.6%) in asymptomatic patients as well as a rise in the number of patients undergoing Chiari posterior fossa decompression surgery (PFD). The type of surgical intervention varies widely. At our institution, 104 (37%) Chiari surgeries were bone-only PFD with/without outer leaf durectomy, whereas 177 (63%) were PFD with duraplasty. We did not find a significant difference in outcomes between the PFD and PFDD groups (p = 0.59). An analysis of failures revealed a significant difference between patients who underwent tonsillar coagulation versus those whose tonsils were not manipulated (p = 0.02).

CONCLUSION

While the optimal surgical intervention continues to remain elusive, there is a shift away from intradural techniques in favor of a simple, extradural approach (including dural delamination) in pediatric patients due to high rates of clinical and radiographic success, along with a lower complication rate. The efficacy, safety, and necessity of tonsillar manipulation continue to be heavily contested, as evidence increasingly supports the efficacy and safety of less tonsillar manipulation, including our own experience.

Scoliosis in patients with Chiari malformation type I

The literature about the association between Chiari malformations (CMs) and scoliosis has been growing over the last three decades; yet, no consensus on the optimal management approach in this patient population has been reached. Spinal anomalies such as isolated syrinxes, isolated CM, and CM with a syrinx are relatively common among patients with presumed idiopathic scoliosis (IS), a rule that also applies to scoliosis among CM patients as well. In CM patients, scoliosis presents with atypical features such as early onset, left apical or kyphotic curvature, and neurological deficits. While spinal X-rays are essential to confirm the diagnosis of scoliosis among CM patients, a magnetic resonance imaging (MRI) is also recommended in IS patients with atypical presentations. Hypotheses attempting to explain the occurrence of scoliosis in CM patients include cerebellar tonsillar compression of the cervicomedullary junction and uneven expansion of a syrinx in the horizontal plane of the spinal cord. Early detection of scoliosis on routine spinal examination and close follow-up on curve stability and progression are essential initial steps in the management of scoliosis, especially in patients with CM, who may require full spine MRI to screen for associated neuro-axial anomalies; bracing and spinal fusion may be subsequently pursued in high-risk patients.

Anterior Spinal Overgrowth of the Thoracic Spine May Not Be Involved in the Initiation of Adolescent Idiopathic Scoliosis

OBJECTIVE

To compare vertebral morphology among patients with adolescent idiopathic scoliosis (AIS), patients with Chiari I malformation (CMS)-associated scoliosis, and normal control subjects, with the goal of determining the role of anterior column overgrowth in the development of AIS.

METHODS

One hundred and forty adolescent girls were enrolled (50 with AIS, 40 with CMS, and 50 control subjects). Thoracic computed tomography images were obtained for all subjects. Anterior height of the vertebral body (VBHa), posterior height of the vertebral body (VBHp), and height of the pedicle (PH) were measured for each level. Finally, the ratios of VBHa and VBHp to PH were calculated and compared among the 3 groups.

RESULTS

Compared with the control group, both the AIS and CMS groups exhibited consistently longer VBHa and VBHp for most thoracic vertebral bodies, whereas the PH of most vertebral bodies was shorter in both AIS and CMS groups. Moreover, the ratios for differential growth between the anterior and posterior elements of each thoracic vertebra in both the AIS and CMS groups were significantly larger than the ratios in the control group. However, for all mentioned parameters, there were no significant differences between the AIS and CMS groups.

CONCLUSIONS

Faster growth of the anterior spinal column was confirmed by longer vertebral bodies and shorter pedicles in both patient groups. Relative anterior spinal overgrowth of the thoracic spine is not involved in the initiation of AIS, and the abnormal growth pattern of the vertebral body in AIS might be a secondary change to the spinal curve.

Current management of pediatric chiari type 1 malformations

OBJECTIVES

Pediatric Chiari Type 1 Malformations (CM1) are commonly referred for neurosurgical opinion. The ideal management in children regarding surgical and radiographic decision making is not clearly delineated.

PATIENTS AND METHODS

We retrospectively reviewed our cohort of patients age 18 years and younger referred to a single neurosurgeon for CM1. Baseline MRIs of the spine were obtained. Non-operative patients had repeat imaging at 6-12 months. Patients who underwent an operation (decompression with/without duraplasty) had repeat imaging at 6 months.

RESULTS

One hundred and thirty-two patients with mean age of 10 years met inclusion criteria. All patients had post-operative symptomatic improvement. We identified 26 patients with syrinx, 8 with scoliosis, 3 with hydrocephalus, and one had tethered cord. The average tonsillar descent was 8.1 mm in the non-operative group and 11.9 mm in the operative group. Ninety-five patients were managed conservatively (72%). Thirty-seven were offered surgery (28%), and 33 patients underwent intervention; 21 with duraplasty (64%) and 12 without (36%).

CONCLUSIONS

Pediatric patients with CM1 require both clinical and radiographic follow-up. Duraplasty may be performed if decompression fails to relieve symptomatology, but is not always needed. CM1 continues to present a challenge in surgical decision making. Adhering to a treatment paradigm may help alleviate difficult decision-making.

Chiari I Malformation and Basilar Invagination in Fibrous Dysplasia: Prevalence, Mechanisms, and Clinical Implications

Fibrous dysplasia (FD) is a mosaic disorder of benign fibro-osseous lesions, which may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). Cranial base abnormalities, including Chiari I malformation (CM1), in which the cerebellum extends below the foramen magnum, and secondary basilar invagination (BI), in which the odontoid prolapses into the posterior cranial fossa, are potentially serious complications of metabolic bone disorders. The purpose of this study was to determine the prevalence, natural history, and risk factors for CM1 and BI in patients with FD/MAS, and to determine mechanisms of cranial base deformities. Clinical and radiographic data from subjects in an FD/MAS natural history study were evaluated and compared to normal controls. In 158 patients with craniofacial FD, 10 (6.3%) cases of CM1 and 12 (7.6%) cases of BI were diagnosed. No cranial base abnormalities were identified in 10 control subjects. Craniomorphometric and volumetric analyses identified cranial constriction and cranial settling as the primary mechanisms of cranial base abnormalities, whereas intracranial hypertension was a contributing factor in a minority of subjects. Longitudinal analyses found progression of odontoid position with age, but no progression of tonsillar position. No endocrinopathies were associated with CM1. MAS endocrinopathies associated with BI included hyperthyroidism (odds ratio [OR] 12.0; 95% confidence interval [CI], 2.9 to 55.6; p < 0.01), precocious puberty (OR 5.6; 95% CI, 1.2 to 26.0; p < 0.05), and hypophosphatemia (OR 7.7; 95% CI, 1.9 to 27.0; p < 0.01). Scoliosis was associated with both CM1 (OR 4.8; 95% CI, 1.1 to 22.8; p < 0.05) and BI (OR = infinity; 95% CI, 4.7 to infinity; p < 0.01). This study successfully characterized cranial base abnormalities in FD/MAS and the pathophysiological connection between them. These findings support routine screening for cranial base abnormalities in patients with craniofacial FD, as well as aggressive management of contributory risk factors. © 2018 American Society for Bone and Mineral Research.

Management of hydrocephalus and subdural hygromas in pediatric patients after decompression of Chiari malformation type I: case series and review of the literature

OBJECTIVE

Hydrocephalus associated with subdural hygromas is a rare complication after decompression of Chiari malformation type I (CM-I). There is no consensus for management of this complication. The authors present a series of 5 pediatric patients who underwent CM-I decompression with placement of a dural graft complicated by posterior fossa hygromas and hydrocephalus that were successfully managed nonoperatively.

METHODS

A retrospective review over the last 5 years of patients who presented with hydrocephalus and subdural hygromas following foramen magnum decompression with placement of a dural graft for CM-I was conducted at 2 pediatric institutions. Their preoperative presentation, perioperative hospital course, and postoperative re-presentation are discussed with attention to their treatment regimen and ultimate outcome. In addition to reporting these cases, the authors discuss all similar cases found in their literature review.

RESULTS

Over the last 5 years, the authors have encountered 194 pediatric cases of CM-I decompression with duraplasty equally distributed at the 2 institutions. Of those cases, 5 pediatric patients with a delayed postoperative complication involving hydrocephalus and subdural hygromas were identified. The 5 patients were managed nonoperatively with acetazolamide and high-dose dexamethasone; dosages of both drugs were adjusted to the age and weight of each patient. All patients were symptom free at follow-up and exhibited resolution of their pathology on imaging. Thirteen similar pediatric cases and 17 adult cases were identified in the literature review. Most reported cases were treated with CSF diversion or reoperation. There were a total of 4 cases previously reported with successful nonoperative management. Of these cases, only 1 case was reported in the pediatric population.

CONCLUSIONS

De novo hydrocephalus, in association with subdural hygromas following CM-I decompression, is rare. This presentation suggests that these complications after posterior fossa decompression with duraplasty can be treated with nonoperative medical management, therefore obviating the need for CSF diversion or reoperation.

Is the routine use of magnetic resonance imaging indicated in patients with scoliosis?

Background

To assess the reliability of the indicators for performing magnetic resonance imaging in patients with scoliosis and assess the incidence of neural axis anomalies in a population with scoliosis referred to a specialist centre.

Methods

A retrospective review of magnetic resonance imaging (MRI) reports of all patients under the age of 18 who underwent a pre-operative MRI for investigation of their scoliosis between 2009 and 2014 at a single institution was performed.

Results

There were 851 patients who underwent an MRI scan of their whole spine with a mean age of 14.08 years. There were 211 males and 640 females. One hundred and fourteen neural axis abnormalities (NAA) were identified. The presence of a left sided thoracic curve, a double thoracic curve, being male nor being diagnosed before the age of 10 were found to be statistically significant for the presence of a NAA. Furthermore, 2.34% of patients were also found to have an incidental finding (IF) of an extraspinal abnormality.

Conclusions

From our series, the reported indications for performing an MRI scan in the presence of scoliosis are not reliable for the presence of an underlying NAA. We have demonstrated that there is a number of intra and extra dural anomalies found on MRI without clinical symptoms and signs. This acts as normative information for this group.

Keywords

Scoliosis; magnetic resonance imaging (MRI); neural axis abnormalities (NAA); adolescent idiopathic scoliosis (AIS).

Intraspinal Anomalies in Early Onset Scoliosis: Current Concepts

Early onset scoliosis (EOS) is deformity of the spine below the age of 5 years. Children with EOS are at risk of impaired thoracic cage development and pulmonary maturation. Initial evaluation consists of determining the etiological cause for EOS, i.e., congenital, neurogenic, idiopathic, or syndromic. The advent of magnetic resonance imaging in recent times has lead to increased awareness of neurogenic causes leading to EOS. Evaluation of spinal cord anomalies in EOS is very important as early diagnosis and treatment can help in deformity stabilization and regression. Also, any surgical or nonsurgical intervention to correct the deformity without prior treatment of spinal cord anomalies can lead to disastrous neurological complications.

[Posterior decompression of the craniovertebral junction in syringomyelia combined with Chiari-1 malformation in children]

OBJECTIVE

to develop the algorithm for defining the amount of posterior decompression of the craniovertebral junction in children with syringomyelia combined with Chiari-1 malformation.

MATERIAL AND METHODS

Sixty eight children with syringomyelia and Chiari-1 malformation, under age of 18 years, underwent posterior decompression of the craniovertebral junction (PDCVJ) in the period from January 2001 to June 2016. Seven (10%) patients underwent extradural decompression (EDD), 16 (24%) patients underwent extra-arachnoid duraplasty (EAD), 25 (37%) patients underwent intra-arachnoid dissection (IAD) and duraplasty, and 20 (29%) patients underwent PDCVJ and placement of a fourth ventricle-subarachnoid shunt.

RESULTS

Clinical improvement occurred in 85% of patients, and stabilization was observed in 11% of patients. Syringomyelia regressed in 78% of cases. There were no complications associated with EDD; however, re-operation was required in 3 (43%) cases. In the case of EAD, treatment results were satisfactory in 11 (79%) patients; re-operation was required in 2 (12.5%) cases; there were no complications in the early postoperative period. The highest complication rate of 6 (30%) cases was associated with shunt placement and duraplasty. However, long-term results in this group of patients were satisfactory in 16 (94%) cases, and MRI-based positive changes were observed in 100% of cases.

CONCLUSION

According to our analysis, EAD is the method of choice for PDCVJ in children with syringomyelia and Chiari-1 malformation without myelopathy symptoms. In the presence of myelopathy symptoms, intra-arachnoid dissection (with or without shunting) is an acceptable alternative. To our opinion, the use of EDD in syringomyelia is unadvisable.

Active mechanosensory feedback during locomotion in the zebrafish spinal cord

The investigation of mechanosensory feedback to locomotion has been hindered by the challenge of recording neurons in motion. Genetic accessibility and optical transparency of zebrafish larvae provide means to revisit this question. Glutamatergic Rohon-Beard (RB) and GABAergic CSF-contacting neurons (CSF-cNs) are spinal mechanosensory neurons. Recent studies combining bioluminescence, silencing and optogenetic activation show that mechanosensory neurons enhance speed and stabilize posture during locomotion. RB neurons can modulate speed by projecting onto glutamatergic premotor V2a interneurons during fast swimming, while CSF-cNs inhibit V0-v interneurons sustaining slow swimming. Sensory gating, either through inhibition of sensory interneurons (CoPA) or though the direct inhibition of primary motor neurons by CSF-cNs, mediates postural control. Advanced optical methods have shed light on the dynamics of sensorimotor integration during active locomotion unraveling implications for translational research.

Chiari-related scoliosis: a single-center experience with long-term radiographic follow-up and relationship to deformity correction

OBJECTIVE Previous reports have addressed the short-term response of patients with Chiari-related scoliosis (CRS) to suboccipital decompression and duraplasty (SODD); however, the long-term behavior of the curve has not been well defined. The authors undertook a longitudinal study of a cohort of patients who underwent SODD for CRS to determine whether there are factors related to Chiari malformation (CM) that predict long-term scoliotic curve behavior and need for deformity correction. METHODS The authors retrospectively reviewed cases in which patients underwent SODD for CRS during a 14-year period at a single center. Clinical (age, sex, and associated disorders/syndromes) and radiographic (CM type, tonsillar descent, pBC2 line, clival-axial angle [CXA], syrinx length and level, and initial Cobb angle) information was evaluated to identify associations with the primary outcome: delayed thoracolumbar fusion for progressive scoliosis. RESULTS Twenty-eight patients were identified, but 4 were lost to follow-up and 1 underwent fusion within a year. Among the remaining 23 patients, 11 required fusion surgery at an average of 88.3 ± 15.4 months after SODD, including 7 (30%) who needed fusion more than 5 years after SODD. On univariate analysis, a lower CXA (131.5° ± 4.8° vs 146.5° ± 4.6°, p = 0.034), pBC2 > 9 mm (64% vs 25%, p = 0.06), and higher initial Cobb angle (35.1° ± 3.6° vs 22.8° ± 4.0°, p = 0.035) were associated with the need for thoracolumbar fusion. Multivariable modeling revealed that lower CXA was independently associated with a need for delayed thoracolumbar fusion (OR 1.12, p = 0.0128). CONCLUSIONS This investigation demonstrates the long-term outcome and natural history of CRS after SODD. The durability of the effect of SODD on CRS and curve behavior is poor, with late curve progression occurring in 30% of patients. Factors associated with CRS progression include an initial pBC2 > 9 mm, lower CXA, and higher Cobb angle. Lower CXA was an independent predictor of delayed thoracolumbar fusion. Further study is necessary on a larger cohort of patients to fully elucidate this relationship.

Should all paediatric patients with presumed idiopathic scoliosis undergo MRI screening for neuro-axial disease?

BACKGROUND

Idiopathic scoliosis is a relatively common childhood condition affecting 0.47-5.2% of the population. Traditional interventions focus on orthopaedic correction of the curve angle. There is a spectrum of patients with scoliosis who are found to have neuro-axial abnormality on full MRI of the spine, but not all surgeons request imaging in the absence of neurological symptoms. There is evidence to suggest that treatment of neuro-axial disease may improve scoliosis curve outcome. We therefore sought to estimate what proportion of patients with normal neurology and scoliosis are found to have neuro-axial abnormality on full MRI imaging of the spine, in particular Chiari malformation and syringomyelia.

RESULTS

Out of 11 identified studies consisting of 3372 paediatric patients (age < 18 years), mean weighted proportion demonstrates that 14.7% of patients with scoliosis (Cobb angle > 20°) and normal neurological examination will demonstrate a neuro-axial abnormality on full MRI imaging of the spine. Of patients, 8.3 and 8.4% were found to have Chiari malformation and syringomyelia, respectively.

CONCLUSIONS

Up to one in seven paediatric patients with scoliosis and normal neurological examination will demonstrate neuro-axial disease on MRI imaging of the spine. Given that younger age and earlier age of decompression is associated with improvement in curve angle, it seems important that MRI screening be considered in all patients regardless of neurological examination findings. There is a potentially long-term benefit in these patients. Multi-cross institutional prospective studies are encouraged to further investigate effect on curve angle.

The addition of duraplasty to posterior fossa decompression in the surgical treatment of pediatric Chiari malformation Type I: a systematic review and meta-analysis of surgical and performance outcomes

OBJECTIVE Surgery is the definitive treatment of Chiari malformation Type I (CM-I). It involves posterior fossa decompression, which can be performed along with C-1 laminectomy, reconstructive duraplasty, or tonsil shrinkage. The aim of this study was to provide an updated systematic review and meta-analysis of the latest available evidence regarding posterior fossa decompression only (PFDO) versus posterior fossa decompression with duraplasty (PFDD) in the treatment of CM-I in children. METHODS A literature search was performed in compliance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for article identification, screening, eligibility, and inclusion. Relevant articles were identified from 6 electronic databases from their inception to April 2016. These articles were screened against established criteria for inclusion into this study. RESULTS From 12 relevant studies identified, 1492 pediatric patients treated via PFDD were compared with 1963 pediatric patients treated by PFDO for CM-I. PFDD was associated with greater overall clinical improvement (p = 0.009), along with longer length of stay (p < 0.0001) and more postoperative complications (p = 0.0001) compared with PFDO. No difference was observed between PFDD and PFDO in terms of revision surgery incidence (p = 0.13), estimated blood loss (p = 0.14), syrinx improvement (p = 0.09), or scoliosis improvement (p = 0.95). CONCLUSIONS It appears that the addition of duraplasty to posterior decompression in the definitive treatment of CM-I in children may alter surgical and performance outcomes. In particular, parameters of overall clinical improvement, length of stay, and postoperative complication may differ between children undergoing PFDD and those undergoing PFDO. Current evidence in the literature is of low to very low quality that, as of yet, has not been able to completely control for inherent selection bias both in study design and surgeon preference. Future, large prospective registries and randomized controlled trials are warranted to validate the findings of this study.

Pediatric Chiari malformation type I: long-term outcomes following small-bone-window posterior fossa decompression with autologous-fascia duraplasty

Chiari malformation type I (CM-I) is a common hindbrain disorder that is associated with deformity and elongation of the cerebellar tonsils. Although CM-I occurs in both pediatric and adult patients, its prevalence, clinical features and management in the pediatric population are not well defined. The current study evaluated a consecutive case series of 92 children (38 females and 54 males) who were diagnosed with congenital CM-I. All patients underwent small-bone-window posterior fossa decompression with autologous-fascia duraplasty. Clinical and radiological features were analyzed and long-term follow-up data were recorded. Risk factors associated with clinical outcomes were investigated using comprehensive statistical methods. Out of the 92 children, 11 (12.0%) were asymptomatic. Associated ventricular dilation was observed in 24 children (26.1%) and concomitant syringomyelia was observed in 72 children (78.3%). A total of 44 children (47.8%) showed scoliosis on plain films. Follow-up data (mean duration, 88.6 months) were available for all patients. Syringomyelia was absent or markedly reduced in 56 patients (77.8%). Symptoms were alleviated in 66 patients, remained unchanged in 12 patients and progressed in 3 patients. Statistical analysis indicated that the cerebellar tonsillar descent (CTD) grade, basilar invagination and platybasia influenced the clinical outcome (P<0.05). In conclusion, early recognition and surgical treatment of CM-I in pediatric patients can lead to good outcomes. The current results suggested that small-bone-window posterior fossa decompression with autologous-fascia duraplasty was an effective safe treatment option with a low complication rate. High CTD grade, basilar invagination and platybasia were indicated to be predictors of poor clinical prognosis.

Headache outcomes in children undergoing foramen magnum decompression for Chiari I malformation

OBJECTIVE

A common symptom of Chiari I malformation (CIM) is headache, which is diagnosed using non-validated criteria from the International Headache Society (IHS). CIM-associated headaches should resolve following neurosurgical treatment of the malformation by foramen magnum decompression (FMD). We aimed to validate the IHS criteria and determine (1) the efficacy of FMD in treating headache and (2) whether duraplasty confers an advantage over simple bony decompression in the treatment of this symptom.

METHODS

A retrospective review of CIM cases treated with FMD at Great Ormond Street Hospital from 1989 to 2014 was carried out. Clinical headache characteristics were compared against IHS criteria and correlated with outcome following FMD.

RESULTS

Headache was a presenting symptom in 57/102 (55.9%) of patients. Of these, 42/57 (73.7%) could be classified as Chiari I-type headache. Following FMD, 42/57 (73.7%) of all presenting headaches showed a sustained improvement (>3 months) compared with 32/39 (82.1%) of Chiari I-type headaches. Duraplasty led to a sustained improvement in headache in 32/38 (84.2%) cases compared with 9/16 (56.3%) cases treated with bone-only decompression.

CONCLUSIONS

Our data suggest that 80% of headaches classified as Chiari I-type will show a sustained improvement following FMD, and, as such, the IHS criteria are clinically useful in evaluating symptoms attributable to CIM. For all headaches associated with CIM, duraplasty may confer a benefit in terms of long-term improvement, compared with bone-only decompression.

Long-term evaluation of intraoperative neurophysiological monitoring-assisted tethered cord surgery

PURPOSE

Patients with tethered spinal cord have been investigated for short-term effects after tethered spinal cord surgery in the past. However, little is known about the long-term effects in this patient group. In this retrospective, longitudinal, observational study, a patient sample of a previous report of 65 patients was reassessed to observe the long-term effects of intraoperative neurophysiological monitoring-assisted tethered cord surgery.

METHODS

With the use of patient charts and a survey, patients were scored on four domains: (1) neurological deficits, (2) urological deficits, (3) pain symptoms, and (4) orthopedic deficits. Measurements were performed at four moments in time: (1) preoperatively, (2) postoperatively, (3) follow-up 1 (4.6 years), and (4) follow-up 2 (11.2 years). Besides this, a subgroup analysis and a quality of life questionnaire were performed.

RESULTS

When observing the symptom domains in the long-term, the pain domain appeared to improve most postoperatively after which it remained stable over time. The neurological and urological domains showed a stable, slightly decreasing trend in the long-term follow-up. The orthopedic domain showed a significant increase of the number of patients with scoliosis during the long-term follow-up.

CONCLUSIONS

Lasting effects of stability in the neurological, urological, and pain domains were observed. Close monitoring during follow-up might contribute to early recognition of progressive scoliosis, in spite of detethering, in a risk group defined by females who underwent tethered cord surgery at or under the age of 12 years old with either lipomyelomeningocele, split cord malformation, or myelomeningocele. Detethering does not appear to protect these patients against progressive scoliosis.

Management of progressive late onset scoliosis with magnetic growth rod insertion leading to improvement of neural anomalies-a case report

BACKGROUND

To present the first known reported case of late onset idiopathic scoliosis with concomitant neural anomalies, treated with sequential distraction using magnetic growth rod, had significant improvement in both cranio-cervical and intraspinal anomaly.

METHODS

A caucasian, growing female child (at the age of ten) presented with moderately progressive late onset right thoracic scoliosis. She was found to have Chiari type I malformation and a cervicothoracic syrinx on routine pre-operative MRI scanning. We treated this child by inserting magnetic growing rod (MGR) system. After 48 months of follow up with serial distractions, the metalwork (MGR) was removed due to aseptic wound breakdown and granuloma formation. Subsequently due to the progression of deformity, a definitive posterior instrumented spinal fusion was done. A repeat MRI Scan of the Spine was done prior to this definitive procedure to assess for any residual neural anomalies.

RESULTS

The Chiari type I malformation appeared to have completely resolved, with no cerebellar tonsillar herniation seen, and a significant improvement in the size of the cervicothoracic syringomyelia effectively downgrading it to a prominent central canal.

CONCLUSIONS

This is a unique case of progressive late onset idiopathic scoliosis with associated Chiari malformation and syringomyelia, showing an improvement in these neural anomalies after gradual and protracted distractive lengthening of the spine with MGR.

Factors associated with spinal fusion after posterior fossa decompression in pediatric patients with Chiari I malformation and scoliosis

OBJECTIVE The authors performed a study to identify clinical characteristics of pediatric patients diagnosed with Chiari I malformation and scoliosis associated with a need for spinal fusion after posterior fossa decompression when managing the scoliotic curve. METHODS The authors conducted a multicenter retrospective review of 44 patients, aged 18 years or younger, diagnosed with Chiari I malformation and scoliosis who underwent posterior fossa decompression from 2000 to 2010. The outcome of interest was the need for spinal fusion after decompression. RESULTS Overall, 18 patients (40%) underwent posterior fossa decompression alone, and 26 patients (60%) required a spinal fusion after the decompression. The mean Cobb angle at presentation and the proportion of patients with curves > 35° differed between the decompression-only and fusion cohorts (30.7° ± 11.8° vs 52.1° ± 26.3°, p = 0.002; 5 of 18 vs 17 of 26, p = 0.031). An odds ratio of 1.0625 favoring a need for fusion was established for each 1° of increase in Cobb angle (p = 0.012, OR 1.0625, 95% CI 1.0135-1.1138). Among the 14 patients older than 10 years of age with a primary Cobb angle exceeding 35°, 13 (93%) ultimately required fusion. Patients with at least 1 year of follow-up whose curves progressed more 10° after decompression were younger than those without curve progression (6.1 ± 3.0 years vs 13.7 ± 3.2 years, p = 0.001, Mann-Whitney U-test). Left apical thoracic curves constituted a higher proportion of curves in the decompression-only group (8 of 16 vs 1 of 21, p = 0.002). CONCLUSIONS The need for fusion after posterior fossa decompression reflected the curve severity at clinical presentation. Patients presenting with curves measuring > 35°, as well as those greater than 10 years of age, may be at greater risk for requiring fusion after posterior fossa decompression, while patients less than 10 years of age may require routine monitoring for curve progression. Left apical thoracic curves may have a better response to Chiari malformation decompression.