Resolution Of Syringomyelia Research Articles

Predicting the presence of 4th ventricular outlet obstruction in Chiari I Malformation

IntroductionA subset of children with Chiari 1 malformation (CM-1) have a 4th ventricle arachnoid veil—a thin membrane covering the outlet of the 4th ventricle. Studies suggest that failure to disrupt this veil during posterior fossa decompression can reduce the likelihood of syringomyelia resolution. However, there is no reliable method for predicting the presence of the veil without direct surgical exploration. This study aims to evaluate the association between pre-operative symptoms, radiographic measurements, and the arachnoid veil.MethodsA retrospective review of an institutional database of children evaluated for CM-I was conducted. For patients treated with surgery, operative notes were reviewed to determine if an arachnoid veil was present. Logistic regression was used to test for relationship of clinical variables and radiographic measurements with the presence of an arachnoid veil.ResultsOut of 997 children with CM-1, 226 surgical patients were included in the analysis after excluding those with inadequate documentation. An arachnoid veil was found in 23 patients (10.2%). Larger syrinx, spinal canal, and thecal sac diameters were significantly associated with the presence of a veil, with odds ratios of 1.23 (95% CI 1.2–1.48; p = 0.03), 1.27 (95% CI 1.02–1.59; p = 0.03), and 1.35 (95% CI 1.03–1.77; p = 0.03), respectively. No significant associations were found with any signs or symptoms.ConclusionsArachnoid veil was present in 10% of cases. Radiographic measurements indicating larger syrinx size were the only variables found to be significantly associated with an arachnoid veil. Exploration of the 4th ventricular outlet is recommended for CM-I decompression in the setting of expansile syringomyelia.

Individualized Functional Decompression Options for Adult Chiari Malformation With Syringomyelia and A Novel Scale for Syringomyelia Resolution: A Single-Center Experience.

To compare outcomes of posterior fossa bony decompression alone (PFD) versus PFD with duraplasty (PFDD) versus PFDD with additional obex exploration (PFDDO) in patients with Chiari malformation type I (CMI) combining syringomyelia. Clinical records of adult patients who underwent decompressions from 2014 to 2022 were retrospectively analyzed. The decompression procedure was individualized based on the cerebrospinal fluid pulse in the surgical field. The Chicago Chiari Outcome Scale (CCOS) was used to assess the prognosis of the patients and a novel syringomyelia resolution scale, based on 3-dimensional volume, was introduced. The percentage change in the cervical syrinx volume was classified as follows by resolution: ≥ 70%, 30%-70%, and < 30%. Seventy-eight individuals were enrolled, of which 22, 20, and 36 underwent PFD, PFDD, and PFDDO, respectively. The three decompression groups had no significant difference in the preoperative characteristics and postoperative prognosis. Multivariate analyses revealed that better CCOS was significantly correlated with younger age at surgery (p = 0.018), syrinx originated from lower cervical levels (p = 0.037), narrower preoperative cerebral aqueduct (p = 0.005), and better syrinx volume resolution (p = 0.004). Additionally, a better cervical syrinx volume resolution was significantly correlated with higher CCOS (p = 0.017), narrower cerebral aqueduct (p = 0.035), and better tonsillar descent resolution (p = 0.007). Individualized functional decompression induced an equal effect on CCOS and syrinx volume resolution for all CMI patients with syringomyelia. Our syringomyelia resolution scale facilitates communication and prediction of CMI prognosis.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Patients With Chiari Malformation: Surgical Interventions.

Chiari malformation type I (CIM) diagnoses have increased in recent years. Controversy regarding the best operative management prompted a review of the literature to offer guidance on surgical interventions. To assess the literature to determine (1) whether posterior fossa decompression or posterior fossa decompression with duraplasty is more effective in preoperative symptom resolution; (2) whether there is benefit from cerebellar tonsillar resection/reduction; (3) the role of intraoperative neuromonitoring; (4) in patients with a syrinx, how long should a syrinx be observed for improvement before additional surgery is performed; and 5) what is the optimal duration of follow-up care after preoperative symptom resolution. A systematic review was performed using the National Library of Medicine/PubMed and Embase databases for studies on CIM in children and adults. The most appropriate surgical interventions, the use of neuromonitoring, and clinical improvement during follow-up were reviewed for studies published between 1946 and January 23, 2021. A total of 80 studies met inclusion criteria. Posterior fossa decompression with or without duraplasty or cerebellar tonsil reduction all appeared to show some benefit for symptom relief and syrinx reduction. There was insufficient evidence to determine whether duraplasty or cerebellar tonsil reduction was needed for specific patient groups. There was no strong correlation between symptom relief and syringomyelia resolution. Many surgeons follow patients for 6-12 months before considering reoperation for persistent syringomyelia. No benefit or harm was seen with the use of neuromonitoring. This evidence-based clinical guidelines for the treatment of CIM provide 1 Class II and 4 Class III recommendations. In patients with CIM with or without syringomyelia, treatment options include bone decompression with or without duraplasty or cerebellar tonsil reduction. Improved syrinx resolution may potentially be seen with dural patch grafting. Symptom resolution and syrinx resolution did not correlate directly. Reoperation for a persistent syrinx was potentially beneficial if the syrinx had not improved 6 to 12 months after the initial operation. The full guidelines can be seen online at https://www.cns.org/guidelines/browse-guidelines-detail/3-surgical-interventions .

Spontaneous improvement in syringomyelia in a patient with Chiari 1 malformation: illustrative case.

"Chiari malformation" refers to a spectrum of hindbrain abnormalities characterized by impaired cerebrospinal fluid circulation through the foramen magnum. Syringomyelia is frequently found in patients with Chiari malformation type 1. Although many theories have suggested how cerebrospinal fluid enters and makes the cystic cavity in the spinal cord, the pathogenesis of syringomyelia remains controversial. This report documents a case with spontaneous resolution of syringomyelia followed up by 3-year serial magnetic resonance imaging (MRI). These kinds of cases support a more conservative approach. A 59-year-old female presented to the authors' clinic in June 2019 with a history of Chiari malformation type 1. This symptomatic patient has been followed up with serial MRI. When the last MRI was performed in August 2022, compared with previous imaging, resolution of the syringomyelia was recognized. Because the natural evolution of mildly symptomatic/asymptomatic patients with syringes is unclear, these patients pose a treatment dilemma. Although surgical intervention is a widely accepted therapeutic method, a more conservative approach can be considered in cases with spontaneous resolution. Especially for patients without progressive symptoms, the surgical approach should not be considered as the first step. In view of relapses, follow-up with periodic neurological examinations and radiological imaging is preferrable.

Single-cell transcriptomics reveals ependymal subtypes related to cytoskeleton dynamics as the core driver of syringomyelia pathological development

Syringomyelia is a common clinical lesion associated with cerebrospinal fluid flow abnormalities. By a reversible model with chronic extradural compression to mimic human canalicular syringomyelia, we explored the spatiotemporal pathological alterations during syrinx development. The most dynamic alterations were observed in ependymal cells (EPCs), oligodendrocyte lineage, and microglia, as a response to neuroinflammation. Among different cell types, EPC subtypes experienced obvious dynamic alterations, which were accompanied by ultrastructural changes involving the ependymal cytoskeleton, cilia, and dynamic injury in parenchyma primarily around the central canal, corresponding to the single-cell transcripts. After effective decompression, the syrinx resolved with the recovery of pathological damage and overall neurological function, implying that for syringomyelia in the early stage, there was still endogenous repair potential coexisting with immune microenvironment imbalance. Ependymal remodeling and cilia restoration might be important for better resolution of syringomyelia and parenchymal injury recovery.

Spontaneus resolution of syringomyelia is a rare variant of the disease course: analysis of clinical and neuroimaging descriptions

The cases of syringomyelia described in the literature with spontaneous collapse of the cavity are analyzed. Differences among patients with cavity decay in childhood and adults are assessed. The basic theories of cavity shedding in syringomyelia are presented in this article.

Correlation Among Syrinx Resolution, Cervical Sagittal Realignment, and Surgical Outcome After Posterior Reduction for Basilar Invagination, Atlantoaxial Dislocation, and Syringomyelia.

The correlation among syrinx resolution, occipitoaxial sagittal alignment, and surgical outcome in long-term follow-up seems to have not been clarified. To further explore the relationship between the syrinx resolution and occipitoaxial realignment after posterior reduction and fixation in basilar invagination (BI)-atlantoaxial dislocation (AAD) patients with syringomyelia. A continuous series of 32 patients with BI-AAD and syringomyelia who received direct posterior reduction met the inclusion criteria of this study. Their clinical and imaging data were analyzed retrospectively. Before surgery and at the last follow-up, we used the Japanese Orthopedic Association (JOA) score and the Neck Disability Index (NDI) to assess the neurological status, respectively. The Pearson correlation coefficient and multiple stepwise regression analysis were used to explore the relevant factors that may affect surgical outcomes. There were significant differences in atlantodental interval, clivus-axial angle, occiput-C2 angle (Oc-C2A), cervicomedullary angle (CMA), subarachnoid space (SAS) at the foramen magnum (FM), syrinx size, NDI, and JOA score after surgery compared with those before surgery. ΔCMA and the resolution rate of syrinx/cord as relevant factors were correlated with the recovery rate of JOA (R 2 = 0.578, P < .001) and NDI (R 2 = 0.369, P < .01). What's more, ΔSAS/FMD (SAS/FM diameter) and ΔOc-C2A were positively correlated with the resolution rate of syrinx/cord (R 2 = 0.643, P < .001). With medulla decompression and occipital-cervical sagittal realignment after posterior reduction and fusion for BI-AAD patients with syringomyelia, the structural remodeling of the craniovertebral junction and occipitoaxial realignment could contribute to syringomyelia resolution.

Post-traumatic syringomyelia resolution following surgical treatment: the moniliform syrinx with a better prognosis.

Post-traumatic syringomyelia (PTS) presented as a serious delayed complication after spinal cord injury (SCI). In our preliminary pathological investigation of PTS in an animal model, the endogenous repair was activated during the early stage of the central canal expansion. We thought about whether there might be an "early syringomyelia state" with a better outcome. This study aimed to further understand the pathophysiological basis of PTS's occurrence, development, and outcome. A cross-sectional observational study from a single-center syringomyelia database prospectively maintained at China International Neuroscience Institute (CHINA-INI). A consecutive series of 28 PTS patients at our institution for surgical treatment met the inclusion criteria of this study. Their clinical and imaging data in a long-term follow-up were reviewed retrospectively. We compared the surgical outcome between moniliform and distended syringomyelia based on high‑resolution MRI and syringomyelia-related symptoms. American Spinal Injury Association (ASIA) impairment scale (AIS) grade to assess their neurological status. Through a series of phenotypic comparisons, we found that moniliform-like syrinx belongs to a special morphological state with a shorter natural history. The patients in the moniliform group had a better surgical outcome compared with those in the distended group (P = 0.028): more obvious symptom improvement as shown in Kaplan-Meier analysis (P = 0.033, Chi square = 4.523) and a higher syringomyelia resolution rate (P = 0.024). We consider the delayed post-traumatic syringomyelia with moniliform type with a better surgical outcome and emphasize the importance of timely intervention to restore cerebrospinal fluid circulation.

Chronological Progression and Management of Syringobulbia Caused by Spinal Hemangioblastoma: A Case Series and Review of the Literature

Syringomyelia often accompanies spinal hemangioblastoma (SHB). It often shows progression to the medulla oblongata, dubbed as "syringobulbia", which presents critical symptoms such as dysphagia and respiratory compromise. Appropriate management of chronological syringomyelia progression toward syringobulbia is not set in stone. This study aims to unravel the clinical and chronological behavior of syringobulbia and its management. A single-institution case series study of 5 patients operated for SHB with syringobulbia was conducted. Serial preoperative magnetic resonance imaging scans were analyzed in further details, especially focusing on the chronological progression of syringomyelia. A literature review was performed to describe clinical/imaging characteristics. Chronological imaging analyses revealed that despite the relatively steady progression of syringomyelia over years, it accelerated when developing syringobulbia. Intramedullary signal change ("presyringomyelia") was observed in the area where syringomyeliasubsequently occurred. Literature review yielded another 15 cases of SHB with syringobulbia, totaling 20 cases. Bulbar dysfunction was seen in 4 cases (20%). Gross total resection was performed in all cases except 1, which underwent just syringotomy. Rapid postoperativesymptom improvement was observed in all cases, as well as immediate imaging resolution of syringomyelia. The symptoms associated with syringobulbia often become life-threatening. Notably, its resolution may be near-synchronous to surgical resection of the spinal lesion. The speed of progression of syringomyelia is usually steady, but it may accelerate when extending to syringobulbia. Regular imaging follow-up is thus highly recommended to determine the best timing of intervention when presyringomyelia and syringomyelia are ascending toward the medulla oblongata.

Syringomyelia Resolution Following Chiari Surgery: A Novel Scale for Communication and Research

Lara-Reyna, Jacques MD; Chae, John BA; Tosi, Umberto MD; Souweidane, Mark M MD; Uribe-Cardenas, Rafael MD, MHS; Greenfield, Jeffrey P MD, PhD

One-Year Outcomes of Chiari Type 1 Malformation and Syringomyelia Treated With Posterior Fossa Decompression.

This was a retrospective cohort study. The objective of this study was to evaluate posterior fossa structural differences between Chiari type 1 malformation with and without syringomyelia, and assess data of the improvement of syringomyelia after different surgical options. Syringomyelia is among the most common concomitant complications of Chiari malformation (CM). However, posterior fossa decompression cannot definitely make the syringomyelia disappear even in the long term. Also, there are no universal criteria defining improvement in syrinx. All admitted CM patients at our institution from 2013 to 2018 with a 1-year follow-up were analyzed. Patients without syringomyelia were compared with those who had syringomyelia. Patients were divided into 3 groups according to the procedures performed: posterior fossa decompression versus posterior fossa decompression with duralplasty (PFDD) versus PFDD plus obex unblocking. Divergent prognosis of syringomyelia was defined as a 3-category ordinal variable. A multivariable ordinal regression model was used to estimate the relationship between patient variables and increased odds for better resolution of syringomyelia. No significant linear difference in bony structure was found between syringomyelia and nonsyringomyelia patients. Among syringomyelia patients, the regression analysis demonstrated that patients with shorter posterior fossa height ( P =0.032), lower Pavlov ratio ( P =0.029), and obex unblocking (vs. PFDD, P <0.001; vs. posterior fossa decompression, P =0.037) were more likely to gain a better resolution of syringomyelia. Syringomyelia of CM patients may not simply originate from single linear anatomic variation. Patients with shorter posterior fossa height and lower Pavlov ratio received better syringomyelia resolution. Also, unblocking the obex received better syringomyelia resolution compared with duraplasty alone and bony decompression alone with the avoidance of increased postoperative complications and worse clinical outcomes.

Syringomyelia Resolution Following Chiari Surgery: A Novel Scale for Communication and Research.

The pathophysiological connection between Chiari malformation and syringomyelia is accepted. Debate remains, however, how can we best define changes in syringomyelia following surgery. To introduce a grading system focusing on syrinx reduction based on routinely and reproducible radiological information, and provide a suggestion of the application of this scale for prediction of patient's prognoses. Data from 48 patients with Chiari malformation and syringomyelia were compiled. We calculated syrinx cross-sectional area by approximating an ellipse in the largest axial plane. We compared the percentage of reduction or enlargement following surgery. The percentage change was grouped into four grades: Grade 0=Increasing size, grade I≤50% reduction, grade II=50% to 90% reduction, grade III≥90% reduction. A total of 89.6% of patients had syrinx improvement after surgery. A total of 5 patients were grade 0, 14 were grade I, 20 patients were grade II, and 9 patients met criteria for grade III. The mean postoperative syrinx area was 24.1mm2 (0-169mm2) with a mean syrinx reduction of 62.7%. Radiological improvement of syringomyelia can be mathematically defined and standardized to assist in communication in outcome-based trials. Radiological resolution is expected most patients.

Persistent Syringomyelia After Posterior Fossa Decompression for Chiari Malformation

Chiari malformation (CM) is often comorbid with syringomyelia. The treatment of CM via posterior fossa decompression (PFD) may not improve syringomyelia in up to 40% of patients, based on historical cohorts. Management of these patients is problematic, as both reoperation and syrinx shunting have high failure rates in the long term. We retrospectively reviewed our cases in which patients with CM type 1 or 1.5 and syringomyelia underwent PFD without postoperative improvement in syringomyelia. Symptomatology and radiographic measurements were collected at presentation and on the first and latest available postoperative scans and analyzed. We present 2 cases to illustrate the challenges in the management of these patients. Our cohort consisted of 48 consecutive patients with CM and syringomyelia who underwent PFD. Of these, 41 patients had postoperative improvement in or resolution of syringomyelia. We subsequently studied the cohort of 7 patients who underwent PFD with (n= 5) or without (n= 2) durotomy and demonstrated worsening of syringomyelia following surgery. This cohort had mean (±SEM) preoperative syrinx area of 23.9 ± 10.0 mm2. Postoperatively, the mean syrinx area increased to 40.5 ± 9.6 mm2 and 57.3 ± 12.5 mm2 on the first and latest postoperative scans available (P= 0.02), for an increase of 106.9% ± 94.4% and 186.0% ± 107.4% (P= 0.04). Presenting symptoms included occipital headache, paresthesias, visual deterioration, and paraspinal pain. On last follow-up (mean 13.9 ± 4.9 months), the majority of symptoms were resolved in this cohort, despite persistence of syringomyelia. In this small cohort of unique patients, syrinx resolution was not achieved via decompression surgery. Despite "radiographic failure," good symptom control was achieved, with most patients remaining or becoming asymptomatic postoperatively, thus supporting our rationale for what has largely been a conservative approach in this population.

Recrudescence of the syringomyelia after surgery of Chiari malformation type 1 with duraplasty

Background: Few case reports describe an increase in the size of syringomyelia and the worsening of neurologic symptoms after surgery for foramen magnum decompression. We report three such cases.Material and method: Retrospective review of patients with Chiari malformation (CM) and syringomyelia operated at the Erzurum Regional Hospital, Department of Neurosurgery between 1 January 2008 and 18 June 2018.Results: A total of 118 patients were operated during the study period. Of the 118 patients, 81 were females, 37 were males. Ages range between 4 and 82 years, mean 38 years. Cervical or thoracic syringomyelia was found in 81 patients. Decompressive surgery with duraplasty was performed in all patients, and the patients were followed at least 2 years. The syrinx was the same or smaller in volume in 74 patients postoperatively, however, in three patients (3.7% of all patients with syringomyelia), the syrinx increased in volume.Conclusions: In this study, it was observed that an improvement or resolution of syringomyelia in 74 patients (91.3%) after decompression. There were no changes in the cavity in 4 and increased size in 3.

Clinical deterioration despite syringomyelia resolution after successful foramen magnum decompression for Chiari malformation - Case series

Neurosurgical treatment is recommended for symptomatic syringomyelia and the post-operative radiological resolution of the syringomyelia is associated with an improvement or at least stability of the patient's pre-operative symptoms. We reviewed syringomyelia treatment in our centre over the last five years for clinical outcome, surgical complications, post operative MRI and long term symptom resolution. 50 cases of symptomatic syringomyelia underwent foramen magnum decompression and expansile watertight duroplasty. While the outcomes for majority are similar to what published in literature, three of them developed typical syringomyelia symptoms after initial good recovery and radiological resolution of syrinx. Syringomyelia symptoms may appear or worsen following successful surgical treatment and radiological resolution of syrinx and it is important to counsel young people and their family regarding this.

No significant difference between chiari malformation type 1.5 and type I

ObjectiveChiari malformation Type 1.5 (CM 1.5) was defined as the association of Chiari malformation Type I (CM I) and brainstem herniation. The objective was to demonstrate the difference of clinical features and surgical outcomes between CM 1.5 and CM I. Patients and methodsAll CM 1.5 and CM I adult patients who underwent posterior fossa decompression with duraplasty at our institution between 2006 and 2010 were retrospectively reviewed. Clinical characteristics, imaging features, and long-term outcomes were compared between CM 1.5 and CM I patients. ResultsA total of 142 adult patients were enrolled, including 27 CM 1.5 and 115 CM I patients. The average follow-up period was 102 months. Age at diagnosis was significantly younger in CM 1.5 group than CM I group (p=0.039). And the degree of tonsillar herniation was significantly more severe in CM 1.5 group than CM I group (p<0.001). There was no significant difference in other clinical and imaging characteristics. Moreover, improvement of symptoms was observed in 21 CM 1.5 patients (77.8%) and 94 CM I patients (81.7%), and no significant difference was detected (p=0.637). There was no significant difference in the resolution of syringomyelia between CM 1.5 (72.7%) and CM I (76.5%) patients, either (p=0. 710). ConclusionsAlthough CM 1.5 patients presented with brainstem herniation and more severe tonsillar herniation, other clinical and imaging features and surgical outcomes were similar with CM I patients. We think CM 1.5 is just a subtype of CM I, rather than a unique type of Chiari malformations.

Dorsal Arachnoid Web and Scalpel Sign: A Diagnostic Imaging Entity.

A case of 60-year-old woman with idiopathic syringomyelia and progressive myelopathy by dorsal arachnoid web is discussed. One focal indentation along the dorsal surface of the spinal cord at the T3 vertebral body level revealed the scalpel sign, a radiologic entity diagnostic of a dorsal thoracic arachnoid web. T2-T3 laminectomy for the resection of dorsal arachnoid band was performed. Careful sectioning of the web resulted in visual apparent relief of the compression and good functional recovery. In patients with presumed idiopathic syringomyelia, imaging studies should be closely inspected for the presence of transverse arachnoid web. This extramedullary transverse band of arachnoid tissue extends to dorsal surface of the spinal cord, resulting in mass effect and dorsal indentation, known as scalpel sign because of its apparent resemblance to a scalpel on sagittal imaging. Early diagnosis with early intervention may benefit greatly patients. Surgical resection of transverse arachnoid web is a minimally invasive procedure with low morbidity, and can result in resolution of syringomyelia and improvement in neurological function.

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%).

Chiari malformation type 1.5 in male monozygotic twins: Case report and literature review

Chiari malformation Type 1.5 (CM 1.5) was defined as the association of Chiari malformation Type I (CM I) and brainstem herniation. The objective was to demonstrate the difference of clinical features and surgical outcomes between CM 1.5 and CM I.All CM 1.5 and CM I adult patients who underwent posterior fossa decompression with duraplasty at our institution between 2006 and 2010 were retrospectively reviewed. Clinical characteristics, imaging features, and long-term outcomes were compared between CM 1.5 and CM I patients.A total of 142 adult patients were enrolled, including 27 CM 1.5 and 115 CM I patients. The average follow-up period was 102 months. Age at diagnosis was significantly younger in CM 1.5 group than CM I group (p = 0.039). And the degree of tonsillar herniation was significantly more severe in CM 1.5 group than CM I group (p < 0.001). There was no significant difference in other clinical and imaging characteristics. Moreover, improvement of symptoms was observed in 21 CM 1.5 patients (77.8%) and 94 CM I patients (81.7%), and no significant difference was detected (p = 0.637). There was no significant difference in the resolution of syringomyelia between CM 1.5 (72.7%) and CM I (76.5%) patients, either (p = 0. 710).Although CM 1.5 patients presented with brainstem herniation and more severe tonsillar herniation, other clinical and imaging features and surgical outcomes were similar with CM I patients. We think CM 1.5 is just a subtype of CM I, rather than a unique type of Chiari malformations.

Extramedullary Myxopapillary Ependymoma of the Filum Terminale Associated With Syringomyelia: A Case Report

Abstract Aim: Ependymomas compose the majority of all intradural intramedullary spinal lesions. Filum terminale lesions are rarely associated with syringomyelia. Here we describe a case of extramedullary myxopapillary ependymoma associated with extensive syringomyelia located in the filum terminale. Material and Methods: A 34-year-old man admitted to our clinic with complaints of bilateral leg weakness, back pain and urinary dysfunction. The magnetic resonance imaging (MRI) of the patient showed us a contrast enhanced intraspinal mass at the level of L2 with a syringomyelia extending from L2 level to Th7 level. Results: The patient was operated via lumbar laminoplasty and tumor was totally resected. Conclusion: The removal of tumor is also sufficient for the resolution of syringomyelia and no additional procedure is essential for the treatment of syringomyelia in such cases. This is the first case of extramedullary tumors of the cauda equine with extensive syringomyelia.