Relationship between clinical parameters and malformations in dogs diagnosed with atlanto-axial instability.

Atlanto-axial instability is a common disease that affects toy-breed dogs. Most cases of atlanto-axial instability are congenital. Furthermore, patients with atlanto-axial instability are predisposed to other concurrent diseases. Therefore, this study aimed to retrospectively determine the presence of concurrent diseases in cases with atlanto-axial instability using imaging data and analyze the relationship between clinical parameters and the incidence of complex malformations. The clinical data and imaging findings of 41 toy-breed dogs diagnosed with atlanto-axial instability were analyzed using their medical records and imaging data. Occipital dysplasia (17/27), atlanto-occipital overlapping (22/34), dens dysplasia (27/41), Chiari-like malformation (8/34), syringomyelia (5/34), lateral ventricular enlargement (20/36), and intracranial arachnoid cyst (5/35) were observed in patients with atlanto-axial instability. The body weight of the patients in the groups with atlanto-occipital overlapping and lateral ventricular enlargement was lower than that of those in the groups without these diseases (1.78 ± 0.71 vs 2.71 ± 1.15 kg, P = 0.0269, 1.60 ± 0.40 vs 2.75 ± 1.08 kg, P = 0.001, respectively). Furthermore, when the correlation between the total number of concurrent diseases and the age at onset and body weight was examined, it became clear that lower body weight was associated with the incidence of a greater number of concurrent diseases. Thus, the findings of this study suggest that toy-breed dogs are more likely to present with complex malformations and should be evaluated carefully with additional examinations and treatment methods.

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.

Selective thoracolumbar/lumbar fusion for Syringomyelia-associated scoliosis: a case-control study with Lenke 5C adolescent idiopathic scoliosis.

BACKGROUND: Selective thoracolumbar/lumbar fusion technique was introduced to treat adolescent idiopathic scoliosis (AIS) patients with major thoracolumbar/lumbar curves. Theoretically, this surgical strategy could also be applied to syringomyelia patients. No previous study has specifically addressed the effectiveness of selective thoracolumbar/lumbar fusion for patients with syringomyelia-associated scoliosis. The aim of the study was to investigate the effectiveness of selective thoracolumbar/lumbar fusion for the surgical treatment of patients with syringomyelia-associated scoliosis. METHODS: From February 2010 to September 2016, 14 syringomyelia-associated patients with major thoracolumbar/lumbar curves were retrospectively reviewed. Besides, 30 Lenke 5C AIS patients were enrolled as a control group. Posterior selective thoracolumbar/lumbar fusion was performed for both groups. Patients' demographic, operative, radiological, and quality of life data were reviewed with follow-up. Intragroup comparisons were performed for each parameter. RESULTS: The two groups were matched by age, gender, curve characteristics, duration of follow-up, and all preoperative radiographic parameters except for thoracic kyphosis. After surgery, the average correction rate of the major thoracolumbar/lumbar curve was 82.2 ± 7.8% in the syringomyelia group, which was not significantly different from that of AIS group (82.5 ± 10.6%, P = 0.47). A similar improvement of unfused thoracic curve was observed between the two groups (50.1 ± 16.5% vs. 48.5 ± 26.9%, P = 0.29). During the follow-up, the correction effect of scoliosis was well maintained, without aggravation of the original neural symptoms or fresh permanent neurological deficits. Of note, the number of fusion levels was significantly larger in syringomyelia group than that in AIS group (7.6 ± 1.4 vs. 6.5 ± 1.2, P < 0.01). The average follow up was 47.6 months (36-81 months). CONCLUSION: Similar to AIS cases, syringomyelia-associated scoliosis can be effectively and safely corrected by selective thoracolumbar/lumbar fusion with satisfactory surgical outcomes. However, the syringomyelia group, on average, required an additional fused segment for treatment as compared to the AIS group (7.6 versus 6.5 in the AIS group).

Incidence of intraspinal abnormalities in congenital scoliosis: a systematic review and meta-analysis.

OBJECTIVE: This is the first systematic review and meta-analysis on the overall incidence of intraspinal abnormalities in patients with congenital scoliosis (CS) and potential influencing factors. METHODS: We searched three large electronic databases (PubMed, EMBASE, and Cochrane Library) for potentially relevant studies. The quality of the included studies was assessed independently by two authors using the Methodological Index for Non-Randomized Studies (MINORS) criteria. Data on the number of CS patients, number of CS patients with intraspinal abnormalities, sex of the patients, and CS types were extracted from the included studies. R software was used to pool and analyze all the extracted data. RESULTS: This meta-analysis included 10 articles, and 671 of 1863 CS patients undergoing magnetic resonance imaging (MRI) examinations were identified to have intraspinal abnormalities. The overall incidence of intraspinal abnormalities in the patients with CS was 37% (95% CI, 29-45%). Diastematomyelia was the most common intraspinal abnormality and was detected in 45.60% of the patients with intraspinal abnormalities (306/671). The remaining intraspinal abnormalities included syringomyelia (273/671, 40.69%), tethered cord (190/671, 28.32%), low conus (58/671, 8.64%), intraspinal mass (39/671, 5.81%), Chiari malformation (32/671, 4.77%), fatty filum (27/671, 4.02%), spina bifida (occulta excluded) (17/671, 2.53%), tumor (17/671, 2.53%), cyst (12/671, 1.79%), syringomyelus (4/671, 0.60%), dural ectasia (1/671, 0.15%), and undiagnosed cord MRI hyperintensity (1/671, 0.15%). The patient's sex and CS type were not factors that affected the incidence of intraspinal abnormalities in CS patients (all P > 0.05). CONCLUSIONS: This meta-analysis revealed that the overall incidence of intraspinal abnormalities detected by MRI in CS patients was 37%. Diastematomyelia was the most common intraspinal abnormality. The patient's sex and CS type were not factors that affected the incidence of intraspinal abnormalities in CS patients.

Neurological deficits are present in syndromic craniosynostosis patients with and without tonsillar herniation.

BACKGROUND: Children with syndromic craniosynostosis (sCS) have a higher incidence of cerebellar tonsillar herniation (TH) than the general population. In the general population, TH ≥ 5 mm below the foramen magnum is associated with typical neurological deficits but, in sCS, we do not know whether this degree of TH is required before such deficits occur. OBJECTIVE: This prospective cohort study aimed to determine the association between findings on neurological assessment and cerebellar tonsillar position. METHODS: Magnetic resonance imaging (MRI) was used to determine TH ≥ 5 mm and the presence of syringomyelia. In regard to the outcome of neurological deficits, these were categorized according to: A, cerebellar function; B, cranial nerve abnormalities; and C, sensory or motor dysfunction. RESULTS: Twenty of 63 patients with sCS (32% [95% confidence interval 21-45%]) had TH ≥ 5 mm and/or syringomyelia. There was no significant difference in proportion between individual forms of sCS: 16/34 Crouzon, 2/11 Muenke, 2/12 Apert, and 0/7 Saethre-Chotzen patients. Neurological deficits were prevalent (73% [95% confidence interval 60-83%]), and as frequent in patients with TH ≥ 5 mm and/or syringomyelia as those without. Surgery occurred in 3 patients overall, and only in Crouzon patients. CONCLUSION: Determining the effect of TH ≥ 5 mm on neurologic functioning in sCS patients is used to better determine when surgical intervention is warranted. However, we have found that neurological deficits are prevalent in sCS patients, irrespective of cerebellar tonsillar position, suggesting that such findings are developmental and, in part, syndrome-specific central nervous system features.

Prevalence and Impact of Underlying Diagnosis and Comorbidities on Chiari 1 Malformation.

BACKGROUND: Chiari malformation type 1 affects approximately one in 1,000 people symptomatically, although one in 100 meet radiological criteria, making it a common neurological disorder. The diagnosis of underlying conditions has become more sophisticated, and new radiological markers of disease have been described. We sought to determine the prevalence and impact of additional comorbidities and underlying diagnoses in patients with Chiari malformation type 1 on symptomatology and surgical treatment. METHODS: A retrospective review of 612 pediatric patients with a Chiari malformation type 1 diagnosis and imaging data evaluated between 2008 and 2018 was performed. Because of extensive clinical heterogeneity, patients were separated into four categories based on their primary comorbidities (nonsyndromic, central nervous system, skeletal, and multiple congenital anomalies) to identify associations with age of onset, radiographic measurements, syringomyelia, and surgical treatment. RESULTS: The largest group had nonsyndromic Chiari malformation type 1 (70%) and the latest age at diagnosis of any group. In the syndromic group, 6% were diagnosed with a known genetic abnormality, with overgrowth syndromes being the most common. Patients with multiple congenital anomalies had the earliest Chiari malformation type 1 onset, the most severe tonsillar ectopia and obex position, and were overrepresented among surgical cases. Although there were no statistically significant differences between groups and rates of syrinx, we observed differences in individual diagnoses. CONCLUSION: The underlying diagnoses and presence of comorbidities in patients with Chiari malformation type 1 impacts rates of syringomyelia and surgery. Although most Chiari malformation type 1 cases are nonsyndromic, clinical evaluation of growth parameters, scoliosis, and joint hypermobility should be routine for all patients as they are useful to determine syringomyelia risk and may impact treatment.

Prevalence and clinical relevance of underlying pathological conditions in painful adolescent idiopathic scoliosis: a MRI-based study.

STUDY DESIGN: Cross-sectional comparative study. OBJECTIVES: Evaluate prevalence and clinical relevance of an underlying pathology in painful adolescent idiopathic scoliosis (AIS) patients after a non-diagnostic history, physical examination and spinal X-ray using Magnetic Resonance Image (MRI) as diagnostic tool. Discrepancies regarding indications of routine MRI screening in painful AIS patients are multifactorial. Few studies have investigated relationship and practical importance of painful AIS with an underlying pathology by MRI. METHOD: A total of 152-consecutive AIS patients complaining of back pain during a 36-month period were enrolled. All patients underwent whole-spine MRI after a non-diagnostic history, physical examination and spinal X-ray. Underlying pathologies were reported as neural and non-neural axis abnormalities based on MRI reports. Variables such as sex, age, constant or intermittent pain, night pain, back pain location (thoracic or lumbar pain), Cobb-angle and follow-up were evaluated as clinical markers to predict presence of underlying MRI pathologies. RESULTS: The presence of an underlying pathology was found by MRI in 54 painful AIS patients (35.5%). Isolated syringomyelia was the only neural axis abnormality found in 6 patients (3.9%). Non-neural axis abnormalities (31.6%) were composed by: 32 herniated nucleus pulposus, 5 vertebral disc desiccation, 4 ovarian cysts, 3 renal cysts, 2 sacral cysts, and 2 vertebral hemangiomas. There was no association with gender, age of presentation, initial coronal Cobb angle and follow up; with presence of an underlying pathology. Lumbar pain location was identified as an adequate clinical marker that correlated with presence of an underlying pathology (p = 0.01). CONCLUSIONS: Prevalence of underlying pathologies diagnosed by MRI in painful AIS was found high (35.5%), but it's clinical relevance and implication are debatable. The use of MRI did not affect orthopedic management of painful AIS patients who showed an underlying pathology. A thorough evaluation must be performed by clinicians; and discussed with patients and family prior to undergo further imaging management. LEVEL OF EVIDENCE: Level III.

Results of the surgical treatment in children with Chiari malformation type I.

PURPOSE: Our study aimed to evaluate the quality of life of the patients operated due to Chiari malformation type 1 (CM-1) in the Department of Pediatric Neurosurgery, Medical University of Silesia in Katowice. METHODS: We performed a retrospective analysis of 11 patients diagnosed with CM-1 who were treated in our center in the years 2007 to 2016. There were 6 female and 5 male individuals. Short-term evaluation of the outcome was based on comparison of the presenting symptoms and radiological images before and after the surgical treatment. Long-term follow-up was carried out using survey questionnaires based on the Chicago Chiari Outcome Scale (CCOS) devised originally by Aliaga et al. RESULTS: Patients, based on their CCOS score were divided into three groups marked as "improved," "unchanged," and "worse," depending on a range of CCOS score: 13-16, 9-12, 4-8, respectively. The outcome of patients was as follows: 6 patients (55%) were evaluated as improved, and 5 (45%) as unchanged. No patient was classified as worse after surgery. Significant negative Spearman's correlation was found between the CCOS score and patients' age at the time of surgery (R = - 0.85, p = 0.0009). CONCLUSIONS: The decision of whether to operate pediatric patients with CM-1 should be considered very carefully. In our department, the main indication for surgery was the occurrence of clinical symptoms. Our study revealed that in the symptomatic patients, surgery improves their quality of life measured with CCOS.

Surgery for Chiari 1 malformation: the Lille experience.

PURPOSE: Decision-making in chronic tonsillar herniation (CTH) in children is complicated because many cases are diagnosed incidentally; on the other hand, its clinical impact may be underestimated. Furthermore, its surgical management is controversial. METHODS: In the present review, we tried to design a semi-quantitative approach to diagnosis, defining presenting symptoms as compatible, suggestive, or differential diagnoses. We expose our rationale for surgery. We review our experience with extensive posterior fossa decompression (PFD) with systematic dural opening and low threshold for tonsil resection. The aim is to achieve uncontroversial anatomical decompression. RESULTS: We operated 117 children during the last 10 years. Seventeen had complications, mostly hydraulic and minor; although most resolved without consequences, one patient died of unexplained cerebral vasospasm. At last control, 97% were clinically improved. No patient required reoperation for PFD. CONCLUSION: With proper patient selection, extensive PFD is a very efficient operation.

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.

Outcomes and complications for individual neurosurgeons for the treatment of Chiari I malformation at a children's hospital.

PURPOSE: The aim of this study was to evaluate the outcomes and complications for individual surgeons at British Columbia Children's Hospital for the treatment of Chiari I Malformation (CMI) in children. METHODS: This was a retrospective review of patients with CMI who had surgery from 1986 to 2015. We assessed the Chicago Chiari Outcome Scores (CCOS) and complication rates by surgeon. RESULTS: Seventy patients, 38 males and 32 females, underwent posterior fossa decompression including 14 extradural and 56 intradural approaches. Syringomyelia was present in 74.3%. Most syringomyelia improved with no difference between intradural and extradural surgeries. After initial surgery, 13 patients (18.6%) had complications including 2/14 (14.3%) of extradural and 11/56 (19.6%) of intradural surgeries. Two patients required surgical intervention for complications whereas 11 had transient complications. The complication rate by surgeon ranged from 11 to 20% for extradural (2 surgeons only) and 10.5 to 40% for intradural surgeries (4 surgeons). The CCOS ranged from 12 to 15 for extradural and 6 to 16 for intradural. The CCOS ranges for surgeons 1 and 2 were 12-15 and 13-15 respectively for extradural. The CCOS ranges for surgeons 1, 2, 3, and 4 were 12-16, 6-15, 12-16, and 12-16 respectively for intradural. Thirteen patients had a second surgery for CMI. The final CCOS was good in 86% and moderate in 14%. CONCLUSION: There was variability in surgeries performed at BCCH by different surgeons, with variations in CCOS and complication rates. This information is important during decision making, consent process, and for quality improvement.

"Management: opinions from different centers"-the Sankt Augustin experience.

OBJECTIVE: In this "how we do it" survey, we review our management regimen of symptomatic CM1 and provide an analysis of our institutional case series of "bony only" decompression of the craniocervical junction without dural opening. METHODS: In regard to the latter clinical symptomatology, neurological status, electrophysiology data, and pre- and post-surgical MRI were analyzed. Surgery was performed in standard fashion under IOM, evaluated by intraoperative ultrasound. RESULTS: We reviewed 22 patients (mean age at surgery 13 ± 7 years; 11 female, 11 male). Neck pain, occipital headaches, sensory symptoms, and dizziness were the predominating symptoms; 9% had central apnea, 5 patients had scoliosis, and 2 patients had a history of premature synostosis. On MRI, preoperative mean tonsillar herniation was 16.55 ± 6.19, compared to 14.25 ± 6.75 after surgery. About half of patients with syringomyelia (n = 11) experienced imagining improvement after surgery. Patients with neck pain, occipital headaches, dizziness, and sensory abnormalities benefited most from surgery. Of the 6 cases that presented with pathological SSEPs, 4 exhibited improved measurements after surgery. There were no postoperative complications. CONCLUSION: To conclude bony decompression for CM1 resulted in clinical and imaging wise improvement and can be viewed as a safe first-lane option for symptomatic CM1.

Chiari malformation clusters describe differing presence of concurrent anomalies based on Chiari type.

Chiari malformations are structural defects in the posterior fossa where the cerebellum displaces caudally into the foramen magnum and upper spinal canal. These malformations are classified by severity as Types 1-4, each presenting with different associated and/or concurrent conditions and anomalies. The aim of this study was to utilize a nationwide database to study patients with Chiari malformations including their concurrent diagnoses and associated anomalies. Using a retrospective review of the Nationwide Inpatient Sample (NIS) database from 2003 to 2012, Chiari malformations were assessed by Chiari type and rates of concurrence for various additional anomalies were evaluated using cross-tabulations. There were 305,726 national cases of Chiari Type 1, 119,632 cases of Chiari Type 2, 15,540 cases of Type 3, and 79,663 cases of Type 4. Overall 44.3% of Chiari patients have at least one concurrent anomaly. Stratified by Chiari Type, 7.1% of Type 1 patients, 12.3% of Type 2, and 100% of Type 3 and 4 have at least one concurrent anomaly. The most common isolated neurologic associations were tethered cord, syringomyelia, and hydrocephalus, while the most common anomaly clusters were syringomyelia and scoliosis in Type 1 (0.63), tethered cord syndrome and scoliosis (0.72%) in Type 2, encephalocele and acquired hydrocephalus (11.45%) in Type 3, and reduction deformity of the brain with acquired hydrocephalus (15.95%) in Type 4. Chiari malformations have strong associations with other abnormalities outside of known relationships in the current classification. While neurologic abnormalities are most common, additional body systems are frequently involved especially with worsening hindbrain defects.

Incidence of Neuraxial Abnormalities Is Approximately 8% Among Patients With Adolescent Idiopathic Scoliosis: A Meta-analysis.

BACKGROUND: Several studies have sought to address the role of routine preoperative MRI in patients with adolescent idiopathic scoliosis (AIS) undergoing deformity correction. Despite similar results regarding the prevalence of neuraxial anomalies detected on MRI, published conclusions conflict and give opposing recommendations. Lack of consensus has led to important variations in use of MRI before spinal surgery for patients with AIS. QUESTIONS/PURPOSES: This systematic review and meta-analysis of studies about patients with AIS evaluated (1) the overall proportion of neuraxial abnormalities; (2) the patient factors and curve characteristics that may be associated with abnormalities; and (3) the proportion of patients who underwent neurosurgical intervention before scoliosis surgery and the kinds of neuraxial lesions that were identified. METHODS: We performed a search of four electronic databases (PubMed, EMBASE, CINAHL Plus, and SCOPUS) utilizing search terms related to routine MRI and AIS, yielding 206 articles. Studies included had at least 20 participants, patients with ages 11 to 21 years, and a Methodological Index for Non-Randomized Studies (MINORS) study quality score of 8 and 16 points for noncomparative and comparative studies, respectively. Non-English manuscripts, animal studies, and those that did not include patients with AIS solely were excluded. Eighteen articles with 4746 patients were included for analysis of the overall proportion of neuraxial abnormalities, 12 articles with 3028 patients for analysis by sex, eight articles with 1603 patients for right main thoracic curve, eight articles with 665 patients for a left main thoracic curve, and 13 articles with 3063 patients and 230 (7.5%) abnormalities for number of neurosurgical interventions before scoliosis correction. The mean MINORS score for studies included was 14 (range, 10-20). Each study was analyzed for the proportion of patients identified with neuraxial abnormalities and associations with specific demographics. We determined the proportion of patients who underwent surgical interventions before scoliosis surgery as well as the types of neuraxial lesions identified. The articles were assessed for heterogeneity and publication bias. Because all groups were determined to be heterogeneous, a random-effects model was used for each group in this meta-analysis; with this analysis, an overlap of 95% confidence intervals suggests no difference at the p < 0.05 level, but this analytic approach does not provide p values. RESULTS: The pooled proportion of neuraxial abnormalities detected on MRI was 8% (95% confidence interval [CI], 6%-12%). With the numbers available, we found no difference in the proportion of male and female patients with neuraxial abnormalities (18% [95% CI, 11%-29%] versus 9% [95% CI, 6%-12%], respectively). Likewise, there was no difference in the proportion of pooled neuraxial abnormalities in right and left curves (9% [95% CI, 6%-14%] versus 15% [95% CI, 5%-35%], respectively). In the subset of abnormalities analyzed for number of neurosurgical interventions before scoliosis correction, the pooled proportion showed that 33% (95% CI, 24%-43%) underwent neurosurgical intervention before deformity correction. The most common abnormalities of the 367 found on MRI were syringomyelia in 127 patients (35%), Arnold-Chiari Type 1 malformation with syrinx in 103 patients (28%), and isolated Arnold-Chiari Type 1 malformation in 91 patients (25%). CONCLUSIONS: The proportion of patients with AIS who have neuraxial abnormalities is high (8%) and a large number undergo surgical intervention before scoliosis reconstruction. We did not find any particular demographic variables that indicated an increased risk of abnormality. Clinicians should consider advanced imaging before surgical intervention in the treatment of a patient with an idiopathic diagnosis. Preventable variables need to be identified by future studies to establish a better working treatment protocol for these patients. LEVEL OF EVIDENCE: Level III, diagnostic study.

[Treatment of syringomyelia associated with Chiari 1 malformation]. / Lechenie siringomielii u patsientov s anomaliei Kiari.

Syringomyelia (SM) develops due to the disturbance of cerebrospinal fluid dynamics, spinal fixation or a spinal tumor. The disturbance of cerebrospinal fluid dynamics in the area of the foramen magnum leads to the progression of SM in Chiari 1 malformation (CM1). CM1 is the most prevalent pathology of craniovertebral junction associated with SM. The prevalence of CM1 varies from 3 to 8 per 100 000 population but SM is diagnosed in 65% of patients with CM1. Clinical symptoms of CM1 and SM include pain in the occipital area, gait disturbances due to sensitive ataxia, dissociated sensory disorders, dysphagia, paresis of the extremities. In most patients, symptoms of SM progressed over the years. The diagnosis is based on MRI results of the brain and spinal cord. Phase-contrast MRI is used to study the disturbance of cerebrospinal fluid dynamics in details. Progression of SM or CM1 symptoms needs surgical treatment - decompression of the posterior cranial fossa for the recovery of normal cerebrospinal fluid dynamics.

Surgical Management of Adult Reducible Atlantoaxial Dislocation, Basilar Invagination and Chiari Malformation with Syringomyelia.

AIM: To analyze retrospectively the surgical management of reducible atlantoaxial dislocation (AAD), basilar invagination (BI) and Chiari malformation (CHM) with syringomyelia through a single-stage posterior approach. MATERIAL AND METHODS: Forty-three patients with reducible AAD, BI and CHM with syringomyelia underwent surgery from January 2009 to January 2013. Intraoperative restoration followed by posterior decompression and plate-rod placement with occipital cortical screws and C2/C3 lateral mass cortical screws fixation devices were used in all patients. Results were recorded both pre- and postoperatively and these outcome measures included Nurick grading (NG) and radiology findings (atlantodental interval (ADI), space available for the spinal cord (SAC), interval between odontoid and Chamberlain's line (IOC), and the cervicomedullary angle (CMA)). RESULTS: Forty (93%) of the 43 patients were followed up. Thirty-six (90%) patients' symptoms improved and four (10%) stabilized. No patients became progressively worse. The difference between preoperative and postoperative Nurick grades was statistically significant. All patients achieved restoration, including thirty (75%) patients had full restoration and ten (25%) had part restoration. The size of syringomyelia was obviously decreased in 32 (80%) patients and stable in 8 (20%) patients. All radiology findings (ADI, IOC, SAC, CMA) showed significant changes from pre- to postoperative (p < 0.01). CONCLUSION: Intraoperative distraction, extension combined posterior decompression with use of plate-rod-screws occipitocervical fusion device is an effective method to treat AAD, BI and CHM with syringomyelia.

The prevalence of intraspinal anomalies in infantile and juvenile patients with "presumed idiopathic" scoliosis: a MRI-based analysis of 504 patients.

BACKGROUND: Though several studies have reported the incidence of intraspinal neural axis abnormalities in infantile and juvenile "presumed idiopathic" scoliosis, there has been a varying prevalence ranging from 11.1 to 26.0% based on a limited sample size. Therefore, such inconclusive findings have resulted in some questions on the MRI-associated role in the management of these patients. We aimed to investigate the prevalence and distribution of intraspinal anomalies in the infantile and juvenile patients with "presumed idiopathic" scoliosis and to explore the radiographic and clinical indicators with large sample size. METHODS: A total of 504 infantile and juvenile patients diagnosed with "presumed idiopathic" scoliosis were examined for potentially-existing neural axis abnormalities by MRI. Patients were grouped into two cohorts according to the presence of neural axis abnormalities. Radiographic parameters including curve magnitude, curve pattern, location of apex, degree of thoracic kyphosis, and span of curve were recorded and compared between the two groups. The prevalence of the neural abnormalities between the infantile-age group and juvenile-age group was also compared. The student t test was used to evaluate the differences of continuous variables and the chi-square test was used to evaluate the difference of categorical variables. Fisher exact test was applied to detect the difference of the rate of intraspinal anomalies between the "infantile idiopathic scoliosis" and "juvenile idiopathic scoliosis" group. RESULTS: Involving the spinal cord, 94 patients (18.7%) were found to have a neural abnormality: Arnold-Chiari malformation alone in 43 patients, Arnold-Chiari malformation combined with syringomyelia in 18 patients, isolated syringomyelia in 13 patients, diastematomyelia in six patients, tethered cord combined with diastematomyelia in six patients, tethered cord alone in four patients, and other uncommon intraspinal abnormalities in the remaining four patients. Totally Arnold-Chiari malformation with or without syringomyelia accounted for 64.8% (61/94) among all these abnormalities. Male gender, left thoracic curve and right lumbar curve were found to be significantly associated with the presence of neural axis abnormalities on MRI. CONCLUSIONS: The incidence of neural axis abnormalities in the presumed IIS and JIS was 18.7%. Thus a routine MRI evaluation appears warranted for those "presumed idiopathic" scoliosis patients if aged less than 10 years, being male or having left thoracic or right lumbar curve.

Isolated thoracic syrinx in children with Chiari I malformation.

INTRODUCTION: Syrinx has been reported in 25-85 % of children with Chiari malformation type I (CMI), and it is most commonly cervical in location. As a result, cervical MRI is routinely included in an evaluation for CMI. Isolated thoracic syrinx without involvement of the cervical cord in this population is uncommon but clinically important because its presence may influence the decision to operate, surgical techniques employed, or interpretation of follow-up imaging. The purpose of this study was to determine the incidence of isolated thoracic syrinx in a large group of children evaluated for CMI. METHODS: We retrospectively reviewed all patients under 21 years of age who were evaluated for CMI at Columbia University/Morgan Stanley Children's Hospital of New York from 1998 to 2013. All patients underwent MRI of the entire spine as part of the CMI evaluation, regardless of whether surgery was planned. The proportion of patients exhibiting isolated thoracic syrinx was determined. Presenting signs, symptoms, and imaging findings were then studied in an attempt to identify any clinical features associated with isolated thoracic syrinx. RESULTS: We identified 266 patients evaluated over the study period. One-hundred thirty-two patients (50 %) presented with a syrinx, and 12 patients (4.5 % of all patients evaluated and 9.1 % of all patients with a syrinx) had an isolated thoracic syrinx. Demographic variables, clinical presentation, and extent of tonsillar ectopia showed great heterogeneity in this group, and no factor was consistently associated with isolated thoracic syrinx. CONCLUSIONS: Isolated thoracic syrinx is an uncommon but clinically significant finding in children with CMI. Our data demonstrate that the presence of a CMI-related thoracic syrinx cannot be reliably predicted clinically and is therefore likely to be missed in patients who do not undergo complete spinal cord imaging. MRI of the entire spinal cord should be considered for all children undergoing initial evaluation for CMI.

Surgical management of syringomyelia unrelated to Chiari malformation or spinal cord injury.

PURPOSE: Syringomyelia is a misleading disease since the problem always lies elsewhere. Arachnoiditis, because it is radiographically difficult to discern, is an especially insidious cause. To better guide selection from among surgical treatment options for syringomyelia, we reviewed our case series of patients without Chiari malformation or spinal injury. METHODS: Excluding syringomyelia due to Chiari malformation, spinal cord injury, and tumors, 32 patients (mean age 44 years) were operated on between 1995 and 2013 and followed up for a mean of 53.8 months. Presumed causes at diagnosis, clinical and radiological findings, type of operation, clinical and radiological outcome were reviewed. RESULTS: Duration of clinical history varied widely (range 6-164 months). Clinical assessment was based on the McCormick classification (15 independent, 17 dependent). Causes included birth trauma, pyogenic meningitis, tuberculous meningitis, postoperative scarring, dysraphism, and basilar impression. Treatment was local decompression with arachnoid lysis and shunts. Hindbrain-related syringomyelia was differentiated from non hindbrain-related syringomyelia. Hindbrain arachnoiditis was significantly associated with radiological findings at the foramen magnum (p = 0.01) and craniocervical decompression (p < 0.03), with good clinical and radiological outcome at 6 months and later follow-up controls (p = 0.02), whereas uneven results were observed in cases of non-hindbrain arachnoiditis. CONCLUSIONS: To remove the cause of syringomyelia, surgical planning will rely on thorough clinical history and accurate imaging to determine the site of cerebrospinal fluid obstruction. Craniocervical decompression to dissect basal arachnoiditis in the posterior fossa can be recommended in hindbrain syringomyelia. Treatment of non-hindbrain arachnoiditis is more controversial, probably owing to uncertainties about the extent of adhesions.

Management of idiopathic pediatric syringohydromyelia.

OBJECT: Syringohydromyelia is frequently identified on spinal imaging. The literature provides little guidance to decision making regarding the need for follow-up or treatment. The purpose of this study was to review the authors' experience in managing pediatric syringohydromyelia of unknown cause. METHODS: A single-institution retrospective review of all cases involving pediatric patients who underwent spinal MRI from 2002 to 2012 was conducted. Patients with idiopathic syringohydromyelia (IS) were identified and categorized into 2 subgroups: uncomplicated idiopathic syrinx and IS associated with scoliosis. Clinical and radiological course were analyzed. RESULTS: Ninety-eight patients (50 female, 48 male) met the inclusion criteria. Median age at diagnosis of syrinx was 11.9 years. Median maximum syrinx size was 2 mm (range 0.5-17 mm) and spanned 5 vertebral levels (range 1-20 vertebral levels). Thirty-seven patients had scoliosis. The most common presenting complaint was back pain (26%). Clinical follow-up was available for 78 patients (80%), with a median follow-up of 20.5 months (range 1-143 months). A neurological deficit existed at presentation in 36% of the patients; this was either stable or improved at last follow-up in 64% of cases. Radiological follow-up was available for 38 patients (39%), with a median duration of 13 months (range 2-83 months). There was no change in syrinx size in 76% of patients, while 16% had a decrease and 8% had an increase in syrinx size. Thirty-six patients had both clinical and radiological follow-up. There was concordance between clinical and radiological course in 14 patients (39%), with 11 patients (31%) showing no change and 3 patients (8%) showing clinical and radiological improvement. No patients had concurrent deterioration in clinical and radiological course. One patient with scoliosis and muscular dystrophy underwent direct surgical treatment of the syrinx and subsequently had a deteriorated clinical course and decreased syrinx size. CONCLUSIONS: There remains a paucity of data regarding the management of pediatric IS. IS in association with scoliosis can complicate neurosurgical decision making. There was no concordance between radiological syrinx size increase and clinical deterioration in this cohort, indicating that surgical decision making should reflect clinical course as opposed to radiological course.