Natural history of scoliosis in children with syringomyelia

Syrinx reduction due to spontaneous spinal cord tear: demonstration on 3 T MRI and review of the literature

A holocord syringomyelia due to Chiari 1.5 malformation (CM) in a 12-year-old girl was serially imaged with 3 T MRI over 4 years. The serial MRI showed reduction in size of the syrinx, without any surgical intervention or CM improvement, but rather due to spontaneous spinal cord tear. The tear was clearly demonstrated by evidence of flow signal across the tear between syrinx and subarachnoid space at the upper thoracic level. The tear showed spontaneous closure at follow-up. A medullary tear has been described in the adult population as one of the putative causes of spontaneous syringomyelia reduction, but its clear demonstration with modern high-resolution MRI has not been reported in the paediatric population. Moreover, this is the first reported case of syrinx reduction due to spontaneous fissuration in a paediatric patient.

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.

Chiari I malformation in children-the natural history

PURPOSE

To review the natural history of asymptomatic and symptomatic pediatric Chiari I malformations with and without syringomyelia.

MATERIALS AND METHODS

We reviewed the literature for case reports and case series describing the natural history of asymptomatic and symptomatic children with Chiari I malformations with and without syringomyelia. Our review included approximately 700 asymptomatic children without syringomyelia, 100 symptomatic children without syringomyelia, 22 asymptomatic children with syringomyelia, and 11 symptomatic children with syringomyelia. Symptomatic and imaging outcomes at the point of last reported follow-up were noted to describe the natural history of Chiari I malformations in children.

RESULTS

Our review of about 700 asymptomatic children with CM-I without syrinx revealed that most children do not exhibit new-onset symptoms (5-6%) or syrinx (2-3%). The nearly 100 published cases of symptomatic CM-I without syrinx suggest that about half of children report symptomatic improvement (48%) and few report symptomatic worsening (7%). New-onset syrinx is rarely observed (2%). Few cases have been published about asymptomatic and symptomatic CM-I with syrinx as syringomyelia are generally regarded to be an indication for surgical intervention. Nevertheless, all 22 children with asymptomatic CM-I with syringomyelia included in this study were asymptomatic at follow-up, with syrinx resolution observed in 18 children and tonsillar herniation improvement observed in 16 children. Overall, our review of asymptomatic pediatric CM-I with or without syringomyelia suggests that its natural history is much more favorable than previously acknowledged and that the literature generally favors conservative management of these cases.

CONCLUSION

Our review of asymptomatic pediatric CM-I with or without syringomyelia suggests that its natural history is much more favorable than previously acknowledged and that the literature generally favors conservative management of these cases. Further study of symptomatic pediatric CM-I is necessary to better understand its natural history.

International survey on the management of Chiari 1 malformation and syringomyelia: evolving worldwide opinions

INTRODUCTION

In 2003, pediatric neurosurgeons were surveyed under the auspices of the education committee of the International Society for Pediatric Neurosurgery (ISPN) to determine prevailing opinions regarding the management of Chiari I malformation (C1M) with and without associated syringomyelia. In the ensuing years, there has been further information from multiple C1M studies, with regards to indications, success rates of different surgical interventions, and complications. The purpose of this study was to re-evaluate current opinions and practices in pediatric C1M.

MATERIALS AND METHODS

Pediatric neurosurgeons worldwide were surveyed, using an e-mail list provided by the ISPN communication committee chairperson. Respondents were given scenarios similar to the 2003 C1M survey in order to determine opinions regarding whether to surgically intervene, and if so, with which operations.

RESULTS

Of 300 surveys electronically distributed, 122 responses were received (40.6% response rate)-an improvement over the 30.8% response rate in 2003. Pediatric neurosurgeons from 34 different countries responded. There was broad consensus that non-operative management is appropriate in asymptomatic C1M (> 90%) as well as asymptomatic C1M with a small syrinx (> 65%). With a large syrinx, a majority (almost 80%) recommended surgical intervention. Scoliotic patients with CIM were generally offered surgery only when there was a large syrinx. There has been a shift in the surgical management over the past decade, with a bone-only decompression now being offered more commonly. There remains, however, great variability in the operation offered.

CONCLUSION

This survey, with a relatively strong response rate, and with broad geographic representation, summarizes current worldwide expert opinion regarding management of pediatric C1M. Asymptomatic C1M and C1M with a small syrinx are generally managed non-operatively. When an operation is indicated, there has been a shift towards less invasive surgical approaches.

Natural and surgical history of Chiari malformation Type I in the pediatric population

OBJECT The natural and surgical history of Chiari malformation Type I (CM-I) in pediatric patients is currently not well described. In this study the authors discuss the clinical and radiological presentation and outcomes in a large cohort of pediatric CM-I patients treated with either conservative or surgical management. METHODS The authors retrospectively reviewed 95 cases involving pediatric patients with CM-I who presented between 2004 and 2013. The patients ranged in age from 9 months to 18 years (mean 8 years) at presentation. The cohort was evenly split between the sexes. Twenty-five patients underwent posterior fossa decompression (PFD) with either dural splitting or duraplasty. Seventy patients were managed without surgery. Patients were followed radiologically (mean 44.8 months, range 1.2-196.6 months) and clinically (mean 66.3 months, range 1.2-106.5 months). RESULTS Seventy patients were treated conservatively and followed with serial outpatient neurological and radiological examinations, whereas 25 patients were treated with PFD. Of these 25 surgical patients, 11 were treated with duraplasty (complete dural opening) and 14 were treated with a dura-splitting technique (incomplete dural opening). Surgical intervention was associated with better clinical resolution of symptoms and radiological resolution of tonsillar ectopia and syringomyelia (p = 0.0392). Over the course of follow-up, 20 (41.7%) of 48 nonsurgical patients who were symptomatic at presentation experienced improvement in symptoms and 18 (75%) of 24 symptomatic surgical patients showed clinical improvement (p = 0.0117). There was no statistically significant difference in resolution of symptoms between duraplasty and dura-splitting techniques (p = 0.3572) or between patients who underwent tonsillectomy and tonsillopexy (p = 0.1667). Neither of the 2 patients in the conservative group with syrinx at presentation showed radiological evidence of resolution of the syrinx, whereas 14 (87.5%) of 16 patients treated with surgery showed improvement or complete resolution of syringomyelia (p = 0.0392). In the nonsurgical cohort, 3 patients (4.3%) developed new or increased syrinx. CONCLUSIONS The overwhelming majority of CM-I patients (92.9%) managed conservatively do not experience clinical or radiological progression, and a sizeable minority (41.7%) of those who present with symptoms improve. However, appropriately selected symptomatic patients (sleep apnea and dysphagia) and those presenting with syringomyelia should be considered surgical candidates because of the high rates of clinical (75%) and radiological improvement (87.5%).

Headache and Chiari I Malformation in Children and Adolescents

Headache is a common problem in children and adolescents. Its recurrent and disabling nature may lead to use of neuroimaging to exclude secondary causes of headache such as Chiari I malformation (CM I). CM I has a variety of presentation with headache being the most common symptom. CM I can be asymptomatic and is also often found incidentally in neuroimaging done for conditions other than headache. This article reviews the spectrum of headache in patients with CM I.

A prospective natural history study of nonoperatively managed Chiari I malformation: does follow-up MRI surveillance alter surgical decision making?

OBJECT Chiari malformation Type I (CM-I) in children is a common incidental finding. Resolution of cerebellar tonsil ectopia has been reported, but no studies have followed tonsil position over regular intervals throughout childhood. To better elucidate the clinical and radiological natural history of CM-I in children, the authors prospectively followed up children with nonoperatively managed CM-I for up to 7 years. METHODS The study included all children evaluated for CM-I over a period of 12 years for whom surgery was not initially recommended. The study excluded patients with associated conditions, including syringomyelia and hydrocephalus. For all patients, initial management was nonoperative, and follow-up management consisted of annual cervical spine or brain MRI and clinical examination. At each follow-up examination, the neurological examination findings, subjective symptoms, and the position of the cerebellar tonsils on MR images were recorded. An alteration in tonsillar descent of 2 mm or greater was considered a change. RESULTS Neurological examination findings did not change over the course of the study in the 52 children who met the inclusion criteria. Although radiological changes were common, no surgeries were performed solely because of radiological change. Overall, tonsil position on radiological images remained stable in 50% of patients, was reduced in 38%, and increased in 12%. Resolution was seen in 12% of patients. Radiological changes in tonsil position were seen during every year of follow-up. On average, in any given year, 24% of images showed some form of change in tonsil position. A total of 3 patients, for whom no changes were seen on MR images, ultimately underwent surgery for subjective clinical reasons. CONCLUSIONS CM-I in children is not a radiologically static entity but rather is a dynamic one. Radiological changes were seen throughout the 7 years of follow-up. A reduction in tonsillar descent was substantially more common than an increase. Radiological changes did not correlate with neurological examination finding changes, symptom development, or the need for future surgery. Follow-up imaging of asymptomatic children with CM-I did not alter treatment for any patient. It would be reasonable to follow these children with clinical examinations but without regular surveillance MRI.

The association between Chiari malformation Type I, spinal syrinx, and scoliosis

OBJECT Chiari malformation Type I (CM-I) is often found in patients with scoliosis. Most previous reports of CM-I and scoliosis have focused on patients with CM-I and a spinal syrinx. The relationship between CM-I and scoliosis in the absence of a syrinx has never been defined clearly. The authors sought to determine if there is an independent association between CM-I and scoliosis when controlling for syrinx status. METHODS The medical records of 14,118 consecutive patients aged ≤ 18 years who underwent brain or cervical spine MRI at a single institution in an 11-year span were reviewed to identify patients with CM-I, scoliosis, and/or syrinx. The relationship between CM-I and scoliosis was analyzed by using multivariate regression analysis and controlling for age, sex, CM-I status, and syrinx status. RESULTS In this cohort, 509 patients had CM-I, 1740 patients had scoliosis, and 243 patients had a spinal syrinx. The presence of CM-I, the presence of syrinx, older age, and female sex were each significantly associated with scoliosis in the univariate analysis. In the multivariate regression analysis, older age (OR 1.02 [95% CI 1.01-1.03]; p < 0.0001), female sex (OR 1.71 [95% CI 1.54-1.90]; p < 0.0001), and syrinx (OR 9.08 [95% CI 6.82-12.10]; p < 0.0001) were each independently associated with scoliosis. CM-I was not independently associated with scoliosis when controlling for these other variables (OR 0.99 [95% CI 0.79-1.29]; p = 0.9). CONCLUSIONS A syrinx was independently associated with scoliosis in a large pediatric population undergoing MRI. CM-I was not independently associated with scoliosis when controlling for age, sex, and syrinx status. Because CM-I is not independently associated with scoliosis, scoliosis should not necessarily be considered a symptom of low cerebellar tonsil position in patients without a syrinx.

Syrinx resolution is correlated with the upward shifting of cerebellar tonsil following posterior fossa decompression in pediatric patients with Chiari malformation type I

PURPOSE

Chiari malformation type I (CMI) is characterized by deformed hindbrain. This study aimed to quantitatively evaluate the alterations in position of hindbrain after Posterior fossa decompression (PFD), and to identify the factors associated with syrinx resolution in pediatric patients with CMI.

METHODS

Eighty-seven patients, aged from 5 to 18 years, who underwent PFD for CMI between September 2006 and September 2012 were retrospectively reviewed. On mid-sagittal MR images, the position of medulla oblongata and cerebellum was quantitatively evaluated preoperatively and at follow-up. The maximal syrinx/cord (S/C) ratio and syrinx length were also measured. Significant improvement of syrinx was defined as a more than 20 % decrease in maximal S/C ratio or length on follow-up MRI.

RESULTS

Neurological deficits were found in 51 of the 87 patients preoperatively and 37 (72.4 %) of them obtained improvement of their symptoms at the last visit. Overall, upward shifting of the tip of cerebellar tonsil was observed in 66 (75.9 %) patients at the last follow-up. Moreover, the mean longitudinal distance of the tip of cerebella tonsil changed from 16.47 ± 5.00 to 13.89 ± 4.38 mm (P < 0.001) at final follow-up. Significant syrinx resolution was noticed in 79 (90.8 %) cases. Pointed cerebellar tonsils were found in 85 (97.7 %) of our patients preoperatively and 78 (91.8 %) of them acquired round cerebellar tonsils after PFD. The improvement of maximal S/C ratio was significantly correlated with upward shifting of the tip of cerebellar tonsil (P = 0.023).

CONCLUSIONS

Following PFD for CMI, position and morphology of the cerebellar tonsil could revert to normal in most of the pediatric patients, and the upward shifting of the tip of cerebellar tonsil is significantly correlated with syrinx improvement. From this study, PFD without shunting may be effective for syrinx secondary to CMI in pediatric population.

Asymmetry of tonsillar ectopia, syringomyelia and clinical manifestations in adult Chiari I malformation

BACKGROUND

The asymmetry of tonsillar ectopia, syringomyelia, and clinical manifestations, and their correlations in adult Chiari I malformation (CIM) are seldom discussed.

METHODS

Clinical and imaging data of 104 consecutive adult patients with CIM and syringomyelia were retrospectively reviewed. A method was devised to quantify tonsillar and syrinx asymmetry. Correlations between the asymmetrically displaced cerebellar tonsils, the side of the syrinx, clinical presentations, and the curve direction of scoliosis were investigated.

RESULTS

Tonsillar ectopia was left dominant in 46 patients (44.2 %), right dominant in 49 (47.1 %), and symmetrical in nine (8.7 %). The syrinx was left deviated in 44 patients (42.3 %), right deviated in 48 (46.2 %), and centrally located in 12 (11.5 %). A significant correlation was observed between the side of tonsillar herniation and the side of the syrinx (p < 0.001), and also between the descending ratio of tonsillar herniation and the deviation ratio of the syrinx (p < 0.001). The main side the of clinical presentations showed significant correlation with the dominant side of tonsillar herniation (p = 0.009) and the side of syrinx deviation (p = 0.012). In the 49 patients (47.1 %) with associated scoliosis, the curve direction was significantly related to not only the dominant side of tonsillar ectopia (p = 0.0,28) but also the deviated side of the syrinx (p = 0.044). Moreover, the curve magnitude was significantly correlated with the distance of the tonsillar herniation (p = 0.001).

CONCLUSIONS

In adult CIM, most tonsillar herniations are asymmetrical and most syringomyelia is eccentrical. We speculate that the dominant side of tonsillar herniation determines the side of syrinx deviation, which in turn determines the main side of clinical presentations and the convex side of scoliosis. Our results suggest that the more the descended tonsil tilts to one side, the more the syrinx tilts to the same side.

Relationship of syrinx size and tonsillar descent to spinal deformity in Chiari malformation Type I with associated syringomyelia

OBJECT

Chiari malformation Type I (CM-I) is a developmental abnormality often associated with a spinal syrinx. Patients with syringomyelia are known to have an increased risk of scoliosis, yet the influence of specific radiographically demonstrated features on the prevalence of scoliosis remains unclear. The primary objective of the present study was to investigate the relationship of maximum syrinx diameter and tonsillar descent to the presence of scoliosis in patients with CM-I-associated syringomyelia. A secondary objective was to explore the role of craniovertebral junction (CVJ) characteristics as additional risk factors for scoliosis.

METHODS

The authors conducted a retrospective review of pediatric patients evaluated for CM-I with syringomyelia at a single institution in the period from 2000 to 2012. Syrinx morphology and CVJ parameters were evaluated with MRI, whereas the presence of scoliosis was determined using standard radiographic criteria. Multiple logistic regression was used to analyze radiological features that were independently associated with scoliosis.

RESULTS

Ninety-two patients with CM-I and syringomyelia were identified. The mean age was 10.5 ± 5 years. Thirty-five (38%) of 92 patients had spine deformity; 23 (66%) of these 35 patients were referred primarily for deformity, and 12 (34%) were diagnosed with deformity during workup for other symptoms. Multiple regression analysis revealed maximum syrinx diameter > 6 mm (OR 12.1, 95% CI 3.63-40.57, p < 0.001) and moderate (5-12 mm) rather than severe (> 12 mm) tonsillar herniation (OR 7.64, 95% CI 2.3-25.31, p = 0.001) as significant predictors of spine deformity when controlling for age, sex, and syrinx location.

CONCLUSIONS

The current study further elucidates the association between CM-I and spinal deformity by defining specific radiographic characteristics associated with the presence of scoliosis. Specifically, patients presenting with larger maximum syrinx diameters (> 6 mm) have an increased risk of scoliosis.

Brace treatment versus observation alone for scoliosis associated with Chiari I malformation following posterior fossa decompression: a cohort study of 54 patients

PURPOSE

To be deemed effective in preventing curve progression, brace treatment should show alteration of the expected natural history. Most of the reported studies on the effect of bracing on the evolution of Chiari malformation-associated scoliosis (CMS) following posterior fossa decompression (PFD) were small series with inconclusive results. The goal of this study was to investigate whether post-PFD brace treatment for CMS produces better outcomes than observation alone.

METHODS

The clinical and radiographic data of 21 patients treated with observation alone (Ob group) and 33 patients receiving brace treatment (Br group) were retrospectively reviewed. Evolution of scoliosis was defined as progression of Cobb angle of the primary curve of >5°, as compared with that at brace initiation.

RESULTS

At the latest follow-up, curve progression occurred in 10 (30 %) of Br group and 13 (62 %) of Ob group (P = .022). Overall, 8 (24 %) patients in the Br group and 9 (43 %) in the Ob group underwent further scoliosis surgery (P = .151). When analyses were restricted to the 27 braced and 17 observed patients who had reached skeletal maturity or undergone spinal fusion surgery, decreased curve progression and surgical rates were also observed in the Br group though not reaching statistical significance. Results of the survival analysis, however, demonstrated a significantly increased survival proportion in the Br group (0.63 versus 0.35, P = .014).

CONCLUSIONS

Compared with observation alone, bracing treatment following PFD in patients with CMS was observed to reduce the rates of curve progression and scoliosis surgery. However, patients and their parents should be informed that almost a third of patients still go on to surgery.

Is curve direction correlated with the dominant side of tonsillar ectopia and side of syrinx deviation in patients with single thoracic scoliosis secondary to Chiari malformation and syringomyelia?

STUDY DESIGN

A retrospective imaging study.

OBJECTIVE

To conduct an assessment of the correlation of the coronal asymmetries between tonsillar ectopia, syrinx, and scoliosis.

SUMMARY OF BACKGROUND DATA

A few reports have shown that the convex side of scoliosis was on the same side as the dominant tonsillar ectopia or syrinx deviation in a majority of patients. However, this issue remains controversial.

METHODS

A retrospective study was conducted on young patients with a single thoracic scoliosis secondary to Chiari malformation type I and syringomyelia. The curve direction, side of the dominant tonsillar ectopia and side of the syrinx deviation were recorded and assessed quantitatively. The correlations between the asymmetrically displaced tonsils, eccentrically located syrinx, and curve convexity were investigated.

RESULTS

A total of 39 patients were included. The concordance between the deviated side of the eccentrically located syrinx and dominant side of the asymmetrically displaced tonsils was 87.0%. In 88.5% of the patients with an asymmetrically displaced tonsil, the convex side of the scoliosis was concordant with the dominant side of the tonsillar ectopia, and in 86.2% of patients with an eccentrically located syrinx, the convex side of the scoliosis was on the same side as the deviated side of the syrinx. In addition, the dominant tonsillar ectopia, syrinx deviation, and curve direction were all on the same side in 82.6% patients with asymmetrically displaced tonsils and eccentrically located syrinx.

CONCLUSION

Asymmetrically displaced tonsils and eccentrically located syrinxes were common imaging features in these patients. The thoracic spine tended to be convex to not only the dominant side of the asymmetrically displaced tonsil, but also the deviated side of the eccentrically located syrinx. The effect of syrinx deviation on curve convexity is similar to that of dominant tonsillar ectopia in the majority of patients.

Natural history of Chiari malformation Type I following decision for conservative treatment

OBJECT

The natural history of the Chiari malformation Type I (CM-I) is incompletely understood. The authors report on the outcome of a large group of patients with CM-I that were initially selected for nonsurgical management.

METHODS

The authors identified 147 patients in whom CM-I was diagnosed on MR imaging, who were not offered surgery at the time of diagnosis, and in whom at least 1 year of clinical and MR imaging follow-up was available after the initial CM-I diagnosis. These patients were included in an outcome analysis.

RESULTS

Patients were followed clinically and by MR imaging for a mean duration of 4.6 and 3.8 years, respectively. Of the 147 patients, 9 had new symptoms attributed to the CM-I during the follow-up interval. During this time, development of a spinal cord syrinx occurred in 8 patients; 5 of these patients had a prior diagnosis of a presyrinx state or a dilated central canal. Spontaneous resolution of a syrinx occurred in 3 patients. Multiple CSF flow studies were obtained in 74 patients. Of these patients, 23 had improvement in CSF flow, 39 had no change, and 12 showed worsening CSF flow at the foramen magnum. There was no significant change in the mean amount of cerebellar tonsillar herniation over the follow-up period. Fourteen patients underwent surgical treatment for CM-I. There were no differences in initial cerebellar tonsillar herniation or CSF flow at the foramen magnum in those who ultimately underwent surgery compared with those who did not.

CONCLUSIONS

In patients with CM-Is that are selected for nonsurgical management, the natural history is usually benign, although spontaneous improvement and worsening are occasionally seen.

Intraspinal anomalies in scoliosis: An MRI analysis of 177 consecutive scoliosis patients

BACKGROUND

The association of intraspinal neural anomalies with scoliosis is known for more than six decades. However, there are no studies documenting the incidence of association of intraspinal anomalies in scoliotic patients in the Indian population. The guide lines to obtain an magnetic resonance imaging (MRI) scan to rule out neuro-axial abnormalities in presumed adolescent idiopathic scoliosis are also not clear. We conducted a prospective study (a) to document and analyze the incidence and types of intraspinal anomalies in different types of scoliosis in Indian patients. (b) to identify clinico-radiological 'indicators' that best predict the findings of neuro-axial abnormalities in patients with presumed adolescent idiopathic scoliosis, which will alert the physician to the possible presence of intraspinal anomalies and optimize the use of MRI in this sub group of patients.

MATERIALS AND METHODS

The data from 177 consecutive scoliotic patients aged less than 21 years were analyzed. Patients were categorized into three groups; Group A - congenital scoliosis (n=60), group B -presumed idiopathic scoliosis (n=94) and group C - scoliosis secondary to neurofibromatosis, neuromuscular and connective tissue disorders (n=23). The presence and type of anomaly in the MRI was correlated to patient symptoms, clinical signs and curve characteristics.

RESULTS

The incidence of intraspinal anomalies in congenital scoliosis was 35% (21/60), with tethered cord due to filum terminale being the commonest anomaly (10/21). Patients with multiple vertebral anomalies had the highest incidence (48%) of neural anomalies and isolated hemi vertebrae had none. In presumed 'idiopathic' scoliosis patients the incidence was higher (16%) than previously reported. Arnold Chiari-I malformation (AC-I) with syringomyelia was the most common neural anomaly (9/15) and the incidence was higher in the presence of neurological findings (100%), apical kyphosis (66.6%) and early onset scoliosis. Isolated lumbar curves had no anomalies. In group-C, incidence was 22% and most of the anomalies were in curves with connective tissue disorders.

CONCLUSION

The high incidence of intraspinal anomalies in presumed idiopathic scoliosis in our study group emphasizes the need for detailed examination for subtle neurological signs that accompany neuro-axial anomalies. Preoperative MRI screening is recommended in patients with presumed 'idiopathic' scoliosis who present at young age, with neurological findings and in curves with apical thoracic kyphosis.

Care of the adolescent with spina bifida

Myelodysplasia with attendant spinal dysraphic disorders can be and often is progressive. In addition to the neurologic deficit present since the prenatal period, hydrocephalus, Chiari malformations with hydromyelia, tethered cord syndrome, or combinations of one or all lead to changing functional ability and progressive deformities. With recent advances in neurologic monitoring and treatment, many of these deformities can be prevented from appearing or becoming destabilizing if the subtle signs are picked up and early intervention is provided. Advances in urologic surgery have also provided better control of continence in addition to reduced infections and renal destruction. This article reviews the monitoring and treatment considerations that have led to such a significant improvement in outcomes in patients who have myelodysplasia.

The natural history of the Chiari Type I anomaly

OBJECT

Since the advent of MR imaging, an increasing number of asymptomatic or oligosymptomatic patients have been diagnosed with Chiari malformation Type I (CM-I). The decision of whether or not to operate is more difficult in these patients than in those with clear symptoms because of the lack of information about the natural course of this disease.

METHODS

The authors report on their experience in a series of 22 patients with CM-I who were evaluated at the authors' institution, and for whom a conservative approach to treatment was adopted. The patients ranged in age from 1 to 16 years (mean 6.3 years) at diagnosis. Neuroradiological and complete clinical examinations were performed in all patients 6 months after the first observation and every year thereafter. The follow-up period ranged from 3 to 19 years (mean 5.9 years).

RESULTS

Chiari malformation Type I was incidentally detected on MR images in 11 of 22 patients. The remaining 11 patients had minimal clinical signs at presentation that were not regarded as necessitating immediate surgical treatment. Seventeen patients (77.3%) showed progressive improvement in their symptoms or remained asymptomatic at the last follow-up whereas 5 patients (22.7%) experienced worsening, which was mild in 2 cases and required surgical correction in the remaining 3 cases. On MR imaging a mild reduction in tonsillar herniation was appreciated in 4 patients (18.18%), with complete spontaneous resolution in 1 of these. In 16 patients, tonsillar herniation remained stable during follow-up.

CONCLUSIONS

The authors' data confirm the common impression that in both asymptomatic and slightly symptomatic patients with CM-I, a conservative approach to treatment should be adopted with periodic clinical and radiological examinations.

Syringomyelia-associated scoliosis with and without the Chiari I malformation

Although there may be a hereditary component to true idiopathic scoliosis, the condition has no known cause and is not associated with dysraphism. However, scoliosis with an associated syrinx, with or without the Chiari I malformation, sometimes presents as an idiopathic-type curve. Physical examination findings and subtle clues on diagnostic imaging may help the orthopaedic surgeon diagnose scoliosis associated with syringomyelia. Examination findings include asymmetric reflexes and presentation at ages younger than those of patients who present with adolescent idiopathic curves (i.e., 10 to 14 years). Radiologic findings include kyphosis at the apex of the curve. Indications for surgical decompression include progressive neurologic deficits, weakness, pain, and progressive curves. Most orthopaedic surgeons agree that a syrinx should be evaluated neurosurgically before any planned spinal arthrodesis to decrease the risk of neurologic injury connected with surgical correction. The indications for arthrodesis in these patients compared with those with idiopathic curves are evolving.

Cervical spinal motion before and after surgery in patients with Chiari malformation type I associated with syringomyelia

OBJECT

There have been few reports about the cervical spinal motion in patients with Chiari malformation Type I (CM-I) associated with syringomyelia. To investigate this phenomenon, the relationship between the preoperative cervical range of motion (ROM) and the stage of cerebellar tonsillar descent as well as the cervical ROM before and after foramen magnum decompression (FMD) were evaluated.

METHODS

Thirty patients who had CM-I associated with syringomyelia and who underwent FMD participated in the study. The ROM and lordosis angle of the cervical spine were measured on x-ray films. In addition, the relationship between preoperative degree of cerebellar tonsillar descent and the ROM between the levels of the occiput (Oc) and C2 was investigated.

RESULTS

The mean flexion-extension ROM at Oc-C2 was 15.5 degrees before and 14.1 degrees after surgery, and the mean flexion-extension ROM of C2-7 was 55.1 degrees before and 52.8 degrees after surgery. The mean pre- and postoperative lordosis angles at C2-7 were 16.8 and 19.1 degrees, respectively. There was no significant difference between the values measured before and after surgery. There was no correlation between the degree of cerebellar tonsillar descent and the ROM at Oc-C2. CONCLUSIONS. Foramen magnum decompression is an excellent surgical technique that has no effect on the postoperative cervical ROM and cervical alignment.

Abnormal spreading and subunit expression of junctional acetylcholine receptors of paraspinal muscles in scoliosis associated with syringomyelia

STUDY DESIGN

A comparative study was performed among 2 groups of patients: Group A with scoliosis and syringomyelia and Group B with idiopathic scoliosis.

OBJECTIVE

To investigate the denervation of paraspinal muscles and analyze its association with scoliosis in patients with syringomyelia.

SUMMARY OF BACKGROUND DATA

The mechanism by which scoliosis develops secondary to syringomyelia remains unclear. Some authors hypothesize that scoliosis may be caused by an alteration in the innervation of the trunk musculature. Few studies, however, have been reported to testify the presence of denervation of the paraspinal muscles in scoliotic patients with syringomyelia.

METHODS

Forty-one children were enrolled in the study and were divided into 2 groups. Group A consisted of 25 patients with scoliosis associated with syringomyelia. Group B included 16 adolescents with idiopathic scoliosis. Bilateral biopsy of paraspinal muscles was performed during scheduled spinal surgery. Distribution of acetylcholine receptors (AChRs) and acetylcholinesterase was investigated by immunofluorescence staining. RT-PCR was performed to determine the AChRs subunit mRNA expression.

RESULTS

Immunostaining showed that 56% patients in Group A were scored positive for the loss of localization of AChRs to neuromuscular junction, while all Group B patients were negative. gamma-AChR subunit expression was detected in 65% patients in Group A while absent in all samples in Group B. There was no statistical significance of both the positive rate of abnormal spreading and that of gamma subunit expression of AChRs between the convex and concave side in Group A.

CONCLUSION

The denervation of paraspinal muscles is present in some patients with scoliosis associated with syringomyelia. The size of the syrinx and the degree of cerebellar tonsillar descent might seem to have no relation to the denervation of paraspinal muscles.

The outcomes of scoliosis surgery in patients with syringomyelia

STUDY DESIGN

A retrospective review of a consecutive case series.

OBJECTIVE

To describe patient demographics, syrinx morphology, and deformity characteristics, as well as postsurgical correction, progression, and complications.

SUMMARY OF BACKGROUND DATA

Conflicting data are available on the natural and postsurgical history of patients with spinal deformity associated with syringomyelia. This is the largest series in the literature on the surgical outcomes of these patients.

METHODS

All patients treated for spinal deformity at our institution with an associated syrinx were reviewed. Demographics, deformity morphology, treatment methods, and postoperative outcomes were measured and recorded.

RESULTS

Thirteen patients met inclusion criteria. All were Lenke thoracic modifier normal or positive. Ten patients underwent neurosurgical decompression. All curves either progressed or remained unchanged following neurosurgical treatment. The average thoracic kyphosis measured 46 degrees (29 degrees-69 degrees). Thoracic kyphosis was significantly increased compared with a population of adolescent idiopathic patients (P = 0.00002). The average curve before scoliosis surgery was 71 degrees (31 degrees-119 degrees) in the coronal plane and 46 degrees (29 degrees-68 degrees) in the sagittal plane. The average correction from the initial scoliosis surgery was 48% (6%-83%). All patients had spinal cord monitoring or wake-up tests during surgery. There were no instances of spinal cord injury from surgery. Three patients progressed significantly following anterior fusion, 2 of whom required further corrective surgery. Following arthrodesis, 4 patients progressed >10 degrees during follow-up.

CONCLUSION

The lack of thoracic hypokyphosis seen in idiopathic-like curves is a strong indicator of a possible underlying syrinx. Neurosurgical treatment of the syrinx did not improve the scoliosis. Caution should be exercised when choosing fusion levels, and arthrodesis should be planned with the underlying pathology in mind. Scoliosis surgery has proven to be safe in patients with treated syrinx when spinal cord monitoring or wake-up tests are used.

Recent advances in the aetiology of adolescent idiopathic scoliosis

The aetiology of adolescent idiopathic scoliosis (AIS) is still unknown despite many years of research effort. Theories on AIS's aetiology have included mechanical, hormonal, metabolic, neuromuscular, growth, and genetic abnormalities. Amongst these, some factors may be epiphenomena rather than the cause itself. Other factors may even contribute to curve progression, rather than curve initiation. Current views maintain that AIS is a multifactorial disease with genetic predisposing factors [Lowe et al. in J Bone Joint Surg [Am] 82:1157-1168, 2000]. With improvements in diagnostic methods, imaging and genomics, there has been considerable recent work on aetiology. This review aims to bring readers up-to-date with the latest developments in scoliosis research.

Surgical outcomes in adult patients with syringomyelia associated with Chiari malformation Type I: the relationship between scoliosis and neurological findings

Object

The clinical characteristics of pediatric scoliosis associated with syringomyelia have been reported in previous studies, but scoliosis associated with syringomyelia in adults is rarely treated, and there is a paucity of detailed studies. In the present study of adult syringomyelia associated with Chiari malformation Type I, the authors investigated the relationships among the syrinx, scoliosis, and neurological data.

Methods

The population was composed of 27 patients (≥ 20 years of age) who underwent foramen magnum decompression for the treatment of syringomyelia. The patients were divided into two groups: those with scoliosis of 10° or more (Group A) and those without scoliosis (Group B). The authors assessed the length of the syrinx, duration of morbidity, and clinical status before and after surgery based on the Japanese Orthopaedic Association (JOA) Scale.

There were 15 cases in Group A and 12 in Group B. The mean length of the syrinx was 12.8 vertebral bodies (VBs) in Group A and 7.2 VBs in Group B. The mean duration of morbidity was 14.2 years in Group A and 6.8 years in Group B. The mean preoperative JOA score was 10.1 in Group A and 14.4 in Group B, whereas the mean postoperative JOA scores were 11.9 and 15.8, respectively. There were significant differences between Groups A and B in length of the syrinx, duration of morbidity, and pre- and postoperative JOA scores.

Conclusions

In patients with syringomyelia and scoliosis the syringes spanned a greater number of VBs, the duration of morbidity was greater, neurological dysfunction was more severe, and surgical results were poorer. Scoliosis could be a predicting factor of the prognosis in patients with syringomyelia and Chiari malformation Type I.

Spontaneous resolution of syringomyelia without Chiari malformation

A 30-year-old woman presented with a cervical syrinx manifesting as hemihypesthesia. Neuroimaging found no evidence of Chiari malformation or tight cisterna magna. Serial magnetic resonance imaging studies over a 6-year period demonstrated spontaneous and complete resolution of the syrinx accompanied by an asymptomatic clinical course. The natural history of syringomyelia is highly unpredictable. The outcome of surgical treatment for patients with syringomyelia is not always satisfactory, so the indications for surgery are controversial. Spontaneous resolution of syringomyelia unrelated with foramen magnum lesion has various causes. Close follow up of the patient is necessary to monitor for recurrence.

The post-syrinx syndrome: stable central myelopathy and collapsed or absent syrinx

Among 168 cases with neurologic findings of cervicothoracic syringomyelia and MRI findings of Chiari 1 malformation and/or underdevelopment of the posterior cranial fossa, 15 patients (9.1 %) had collapsed, flat syrinxes and 14 patients (8.3 %) did not have syrinxes. Both groups of patients had clinical findings of central myelopathy that had been stable for at least 3 years. Magnetic resonance imaging detected atrophy of the cervical spinal cord in both groups and spontaneous communications between the syrinx and the subarachnoid space in 3 patients of the group with collapsed syrinxes. Analysis of these results and review of the literature suggest that patients with clinical signs of syringomyelia and Chiari 1 malformation or underdeveloped posterior fossa, but with small or absent syringomyelitic cavities, have the "postsyrinx" state as a result of spontaneous collapse of distended syrinxes.

Predictors of progression of scoliosis after decompression of an Arnold Chiari I malformation

STUDY DESIGN

Retrospective study of patients with scoliosis and an Arnold Chiari I malformation requiring operative management.

OBJECTIVES

Determine the factors that could predict whether a particular spinal deformity might progress despite neurosurgical management of Arnold Chiari I malformation.

SUMMARY OF BACKGROUND DATA

Few studies have documented the relationship between diagnosis and treatment of Arnold Chiari I malformation and associated spinal deformities. Most studies mix neural axis abnormalities and contain limited information about the spinal deformity.

METHODS

Medical records, radiographs, and magnetic resonance images of patients were evaluated focusing on age and findings at presentation, characteristics of presenting and follow-up spinal deformities, and the specifics of neurosurgical and orthopedic management. Patients were divided into two groups: those whose curves progressed >10 degrees or to surgical range (largest curve >45 degrees ) after neurosurgical intervention (progressors) and those whose curves stabilized or decreased (nonprogressors).

RESULTS

Eight progressors presented at an average age of 11.4 years (range 2-19) and were followed for 6.3 years (range 2-15). Seven nonprogressors presented at 6.5 years of age (range 5-10) and were followed for 6.6 years (range 3.5-14). Neurosurgical procedures were equivalent in both groups; however, surgical revisions were required in 3 out of 8 progressors and 1 out of 7 nonprogressors. All progressors had a double scoliosis curve; but only one nonprogressor had a double curve. Six out of 8 progressors and 0 out of 7 nonprogressors had a rotation >or=2+ and 50% of progressors had a thoracic kyphosis >50 degrees compared to 1 out of 7 nonprogressors.

CONCLUSIONS

In this series, progression of spinal deformity after neurosurgical management of Arnold Chiari I malformation was associated with later age at neurosurgical decompressions and initial neurologic symptoms, double scoliosis curve patterns, kyphosis, rotation, and larger curve at presentation.

A prognostic model for the presence of neurogenic lesions in atypical idiopathic scoliosis

STUDY DESIGN

Consecutive series of patients with idiopathic scoliosis with atypical features.

OBJECTIVES

The purpose of this study is to define a specific yet sensitive set of signs and symptoms to indicate the use of MRI in patients with atypical idiopathic scoliosis. Specifically, this study empirically defines a new diagnostic test for the presence of neurogenic lesions based on clinical and radiologic data and then reports the properties of this test in relation to MRI as the gold standard.

SUMMARY OF BACKGROUND DATA

The reported prevalence of brain stem and spinal cord abnormalities in patients with idiopathic scoliosis associated with atypical features varies from 0% to 60%. This wide range most likely results from the fact that the samples studied are either not well defined or are heterogeneous across studies. Because of these issues, the likelihood of neurogenic lesions in atypical idiopathic scoliosis is not known; consequently, the decision to order an MRI is controversial.METHODS A total of 1,206 patients coded as having idiopathic scoliosis were identified from our institutional database. Of these, 72 patients had one or more atypical features: early-onset scoliosis, atypical curve, severe curve despite immaturity (>45 degrees ), rapidly progressive curve (>1 degrees per month), back pain, headache, or neurologic abnormalities on clinical examination. All 72 patients underwent brain and spinal cord MRI. Logistic regression was used to determine significant predictors of positive MRI and to define the prognostic model.

RESULTS

Eleven patients (15%) had abnormal findings on MRI. Eight had an Arnold-Chiari type I malformation associated with a syrinx; 1 had an Arnold-Chiari type I malformation; 1 a syrinx; and 1 a cervical syrinx with a conus lipoma. MRI was positive in 5 of 9 patients (55%) with severe curves despite immaturity. Twenty patients had one or more abnormal neurologic signs. Of these, 8 (40%) had a positive MRI, while only 3 of the 52 patients (6%) with a normal neurologic examination (but other atypical features) had a positive MRI. The most predictive model included the variables neurologic abnormalities (yes or no) and severe curve despite immaturity (yes or no). Using this model, patients with atypical characteristics other than severe curvatures or abnormal neurologic abnormalities(s) had a 3% probability (95% confidence interval [CI], 1-12%) of having a positive MRI; patients with abnormal neurologic change(s), but a nonsevere curve, had a 29% probability of a positive MRI (95% CI, 12-53%) and patients with severe curves and no neurologic change(s) had a 32% probability of positive MRI (95% CI, 8-71%). Patients with both a severe curve and abnormal neurologic change(s) had an 86% probability of positive MRI (95% CI, 46-98%). Agreement between this test and the MRI was 75%, with a sensitivity of 82% (95% CI, 48-97%) and a specificity of 74% (95% CI, 61-83%).

CONCLUSIONS

The model derived in this study indicates that the probability of neurogenic lesions is extremely low in most patients with idiopathic scoliosis with atypical features. However, patients with severe curves despite skeletal immaturity and an abnormal neurologic examination have a significant probability of neurogenic lesions. Therefore, clinical efficiency will be enhanced by narrowing the indications for MRI to those patients with these risk factors.

Scoliosis associated with syringomyelia: clinical and radiologic correlation

STUDY DESIGN

A retrospective review with statistical correlations of 112 patients having both scoliosis and syringomyelia was performed.

OBJECTIVE

To determine whether there were significant correlations between the type of scoliosis, location of the syrinx, size of the syrinx, clinical manifestation of the syrinx, and associated lesions such as cord tethering and Chiari malformation (Chiari I or Arnold-Chiari II).

SUMMARY OF BACKGROUND DATA

The coexistence of scoliosis and syringomyelia has been described previously, but these detailed correlations have had minimal attention.

METHODS

All patients at the center with scoliosis of any type plus a syrinx had a detailed chart and radiologic review coupled with detailed statistical analysis.

RESULTS

Scoliosis and syringomyelia were seen in four diagnoses: myelomeningocele, myelomeningocele with congenital scoliosis, congenital scoliosis, and scoliosis with neither congenital anomalies nor myelomeningocele. Chiari malformation and cord tethering appear to have a major relation to scoliosis with syringomyelia.

CONCLUSIONS

Anomalies of the spinal cord or spinal column coexisting with lesions of the central nervous system have significant effects on the syrinx and scoliosis. There is a significant relation between the most caudal level of the syrinx and the locations of the scoliosis.

Idiopathic scoliosis as a presenting sign of familial neurologic abnormalities

STUDY DESIGN

Familial cases of "idiopathic" scoliosis associated with neurologic abnormalities are reported with a review of the literature.

OBJECTIVE

To investigate the prevalence of neurologic abnormalities such as syringomyelia, Chiari 1 malformation, and tonsillar ectopia in patients with genetically determined "idiopathic" scoliosis.

SUMMARY OF BACKGROUND DATA

Idiopathic scoliosis is widely considered to be a genetic disorder of unknown etiology. Magnetic resonance imaging (MRI) studies have shown that several cases of "idiopathic" scoliosis show neurologic abnormalities including syringomyelia and Chiari 1 malformation. Recently, several familial cases of either syringomyelia or Chiari malformation were reported, and it is suspected that genetic factors may influence the development of the craniovertebral malformation. It was hypothesized that some cases of "idiopathic" scoliosis include a craniovertebral malformation that is genetically determined.

METHODS

This study, using clinical examinations and MRI, investigated 71 patients with scoliosis and a family history of "idiopathic" scoliosis in third-degree relatives for the presence of neurologic abnormalities. If neurologic abnormalities were confirmed with MRI, the relatives affected with scoliosis were also examined.

RESULTS

Nine (13%) patients showed neurologic abnormalities on MRI. Magnetic resonance imaging showed syringomyelia with Chiari 1 malformation in four patients, Chiari 1 malformation in three patients, and tonsillar ectopia in two patients. Among the relatives of these patients, 4 of 15 individuals affected with scoliosis also showed neurologic abnormalities on MRI.

CONCLUSIONS

It is suggested that familial neurologic abnormalities may have a wide range of expression, and that some patients with "idiopathic" scoliosis present with genetically determined craniovertebral malformations such as syringomyelia, Chiari 1 malformation, and tonsillar ectopia.