Syringomyelia Research Articles

Prediction of Curve Progression After Posterior Fossa Decompression in Pediatric Patients With Scoliosis Secondary to Chiari Malformation

ObjectiveIn this retrospective radiographic and clinical study, we analyzed the evolution of scoliosis after posterior fossa decompression (PFD) to determine the predictors of curve progression after PFD in patients with scoliosis secondary to Chiari malformation type I (CM-I) and syringomyelia (SM). Institutional Review Board approval was obtained to conduct the study. Previous studies have shown that PFD can improve the associated scoliosis in some patients with CM-I, and certain clinical factors can predict curve progression after PFD. However, the results were often contradictory. MethodsIn our study, 54 patients with CM-I who underwent a standard PFD were divided into 2 groups according to the evolution of scoliosis after PFD. One group consisted of “progressors” with curve progression of more than 5° from before PFD to the final follow-up; the other group consisted of “nonprogressors” with curve stabilization or improvement. Clinical and radiographic data were compared between progressors and nonprogressors. ResultsTwenty-five of the patients received brace treatment, and 11 patients underwent spinal fusion. Nineteen patients were identified as progressors, and 35 were nonprogressors. Age, curve type, curve magnitude, and bracing treatment were independent predictors for curve progression after PFD. Both an age ≥ 10.5 years and a Cobb angle ≥ 44.5° were strongly predictive factors for curve progression. Regarding those patients with an indication for bracing, a significant difference (p=.009) was noted in terms of the evolution of scoliosis between patients with and without bracing treatment. ConclusionPFD had an effect on the regression of scoliosis in 64.8% of the CM-I patients. An age ≥ 10.5 years, a Cobb angle ≥ 44.5°, and double curves were factors that could predict the progression of scoliosis in these patients. Additionally, we advocate that bracing treatment may be effective in some skeletally immature patients.

Letters to the Editor: Syringomyelia

Letters to the Editor: Syringomyelia

Long-term outcome of Cavalier King Charles spaniel dogs with clinical signs associated with Chiari-like malformation and syringomyelia

The disease complex Chiari-like malformation (CM) and syringomyelia (SM) has been associated with the development of neuropathic pain (NeP), and commonly affects Cavalier King Charles spaniels (CKCS). This prospective cohort...

Treatment of Chiari malformation combined with basilar invagination by staged anterior and posterior decompression

Objective There is usually anterior compression of the brain stem in Chiari malformation patients combined with basilar invagination.After anterior decompression,many patients will present elevation of the cerebellar tonsil and resolution of syringomyelia.However,still in some patients,the Chiari malformation and syringomyelia remain unchanged after anterior decompression.This article is to discuss a staged anterior and posterior decompression strategy for the treatment of these patients.Methods 9 cases of Chiari malformation combined with basilar invagination were operated by transoral transpharyngeal odontoidectomy first,observed for 1 -2 months,the Chiari malformation and syringomyelia did not relieve,then posterior foramen magnum decompression,tonsillectomy and expansion of posterior fossa dura combined with occipito - cervical fusion or C1-2 fusion were performed.The patients were followed up for 24 - 60 months ( mean 32 months).Results There was no mortality or severe complication.The clinical symptoms were improved in all patients.The Chiari malformation and syringomyelia were relieved in 8 patients,while unchange in 1 case.Conclusions For Chiari malformation patients combine with basilar invagination,anterior decompression with odontoidectomy should be performed first. In many patients,increase ofposterior fossa volume,improved CSF dynamic may be achieved,posterior fusion will be enough.While in some other patients,only symptoms of basilar invagination may be improved after anterior decompression.So posterior decompression is still important. Key words: Platybasia; Arnold - Chiari malformation; Cranio - vertebral junction malformation; Odontoidectomy ; Occipito - cervical fusion

The efficacy of intraoperative ultrasonography⁃assisted microinvasive cisterna magna reconstruction for Chiari malformation typeIwith syringomyelia

Objective To report the method and effect of intraoperative ultrasonography⁃assisted microinvasive cisterna magna reconstruction for Chiari malformation type Ⅰ with syringomyelia. Methods Ninty⁃three patients suffered from Chiari malformation typeⅠwith syringomyelia were treated by microinvasive cisterna magna reconstruction. The skin incision was 1.50-3.00 cm. The bone removal of foramen magnum was 1.50 cm × 2.00 cm with C1 reserved. Dura and arachnoid were incised and sutured linearly. All of the patients underwent cerebellar tonsillar resection and exploration of median aperture of fourth ventricle. Intraoperative ultrasonography was performed both before and after cerebellar tonsillar resection to judge the effect of cisterna magna reconstruction. According to Tator method, the curative effect was divided into 3 groups, improved, stable and worsen. MRI were reviewed at the same time, and the result was divided into syrinx disappeared, reduced, no change and expanded. Results The operation was successful in all patients. Postoperative complications included cerebellum hemorrhage (n = 1), cerebral infarction (n = 1), hydrocephalus (n = 1), subcutaneous dropsy (n = 2) and were recovered after specific treatment. All patients were followed up for 6 months to 12 months after operation. Thirty⁃six cases were improved, 55 cases were stable, and 2 cases got worse. The MRI showed that the syringomyelia shrinked or disappeared in 90 cases, no change in 3 cases and no expansion. Eighty cases were followed up for 30 months to 36 months after operation, 12 stable cases improved, 1 stable case got worse, while the others remained unchanged. The MRI showed no change was compared with previous follow ⁃ up imaging. Conclusion Microinvasive cisterna magna reconstruction is a surgical procedure with mininal injury, quick recovery, stable effect, fewer complications, and high security. Intraoperative ultrasonography provides reliable data and is easy to perform. DOI：10.3969/j.issn.1672⁃6731.2012.04.015

Questionnaire-based behaviour analysis of Cavalier King Charles spaniels with neuropathic pain due to Chiari-like malformation and syringomyelia

Chiari-like malformation (CM)/syringomyelia (SM) is a disease complex recognised in Cavalier King Charles spaniels (CKCSs) that can lead to neuropathic pain (NeP). In humans, NeP is associated with anxiety, depression and reduced quality of life (QoL). In this study, databases of three specialist veterinary centres were searched and CKCS breed societies and health forums were contacted to identify CKCS with an imaging diagnosis of CM/SM. Owners completed questionnaires on behaviour, signalment, general health status, NeP and QoL. Data were analysed from 122 dogs out of 564 questionnaires completed, after incomplete questionnaires and data from dogs that had other potentially debilitating disease processes were excluded. NeP severity score was significantly and positively correlated with 'stranger-directed' fear (r(S)=0.28), non-social fear (r(S)=0.34), 'separation-related' behaviour (r(S)=0.38), attachment behaviour (r(S)=0.24), excitability (r(S)=0.21) and proxy for pain sensation (r(S)=0.29). Increased NeP was also significantly associated with decreased QoL (r(S)=0.47), ability to settle (r(S)=0.26) and willingness to exercise (r(S)=0.50). Severity of NeP was positively associated with certain fear-associated behaviour and with decreased owner-perceived QoL. Thus, neurobehavioural changes should be considered in the management of NeP in CKCS with CM/SM.

Volume reduction of the jugular foramina in Cavalier King Charles Spaniels with syringomyelia

BackgroundUnderstanding the pathogenesis of the chiari-like malformation in the Cavalier King Charles Spaniel (CKCS) is incomplete, and current hypotheses do not fully explain the development of syringomyelia (SM) in the spinal cords of affected dogs. This study investigates an unconventional pathogenetic theory for the development of cerebrospinal fluid (CSF) pressure waves in the subarachnoid space in CKCS with SM, by analogy with human diseases. In children with achondroplasia the shortening of the skull base can lead to a narrowing of the jugular foramina (JF) between the cranial base synchondroses. This in turn has been reported to cause a congestion of the major venous outflow tracts of the skull and consequently to an increase in the intracranial pressure (ICP). Amongst brachycephalic dog breeds the CKCS has been identified as having an extremely short and wide braincase. A stenosis of the JF and a consequential vascular compromise in this opening could contribute to venous hypertension, raising ICP and causing CSF jets in the spinal subarachnoid space of the CKCS. In this study, JF volumes in CKCSs with and without SM were compared to assess a possible role of this pathologic mechanism in the development of SM in this breed.ResultsComputed tomography (CT) scans of 40 CKCSs > 4 years of age were used to create three-dimensional (3D) models of the skull and the JF. Weight matched groups (7–10 kg) of 20 CKCSs with SM and 20 CKCSs without SM were compared. CKCSs without SM presented significantly larger JF -volumes (median left JF: 0.0633 cm3; median right JF: 0.0703 cm3; p < 0.0001) when compared with CKCSs with SM (median left JF: 0.0382 cm3; median right JF: 0.0434 cm3; p < 0.0001). There was no significant difference between the left and right JF within each group. Bland-Altman analysis revealed excellent reproducibility of all volume measurements.ConclusionA stenosis of the JF and consecutive venous congestion may explain the aetiology of CSF pressure waves in the subarachnoid space, independent of cerebellar herniation, as an additional pathogenetic factor for the development of SM in this breed.

Syrinx resolution after posterior fossa decompression in patients with scoliosis secondary to Chiari malformation type I

Description of syrinx resolution after posterior fossa decompression (PFD) in patients with scoliosis secondary to Chiari malformation type I (CMI) and syringomyelia (SM) has been rarely reported in the literature. This study was performed to investigate the outcome of PFD in patients with scoliosis secondary to CMI and to identify potential predictive factors for better outcome after PFD. Patients with scoliosis secondary to CMI and SM, who had undergone PFD during the period 2000 through 2009, were recruited. Inclusion criteria were (1) age≤18years, (2) diagnosis of SM associated with CMI, (3) scoliosis as the first complaint, (4) having undergone preoperative and follow-up magnetic resonance imaging (MRI). Patients with acquired CMI anomalies or who had received syringosubarachnoid shunting were excluded. The maximal S/C ratio and syrinx length were measured to evaluate syrinx resolution after PFD. A 20% decrease in S/C ratio or length at the latest follow-up was defined as a significant radiographic improvement and complete resolution was used to describe the syrinx disappearing after PFD. 44 patients were recruited. Follow-up MRI was conducted for all 44 patients at 6±3months postoperatively, for 37 patients at 2years±3months, for 26 patients at 4years±3months, and for 15 patients at 6years±3months. 97.7% (43 of 44) of patients showed significant radiographic improvement by MRI. The distance of tonsillar descent (mm) was correlated significantly with the surgical outcome (r=0.116, P=0.013). Significant improvement was observed within 6months postoperatively, with continued slow improvement after that. Syringes showed significant improvement after PFD in most patients with scoliosis secondary to CMI. Resolution generally occurred within 6months follow-up and continued at a slow rate for several years. In addition, the severity of tonsillar descent is a potential predictor for better improvement after standard PFD.

Effectiveness of breeding guidelines for reducing the prevalence of syringomyelia

Several toy breed dogs are predisposed to syringomyelia (SM), a spinal cord disorder, characterised by fluid-filled cavitation. SM is a complex trait with a moderately high heritability. Selective breeding against...

Posterior fossa decompression with tonsillectomy in 104 cases of basilar impression, Chiari malformation and/or syringomyelia

The prime objective in the surgical treatment of basilar impression (BI), Chiari malformation (CM) and/or syringomyelia (SM) is based on the restoration of the normal cerebrospinal fluid (CSF) dynamics at the craniovertebral junction through the creation of a large artificial cisterna magna. A small suboccipital craniectomy has been emphasized to avoid caudal migration of the hindbrain structures into the vertebral canal. Nevertheless, the results showed downward migration of the hindbrain related to that type of craniectomy. The authors present, otherwise, the results of 104 cases of BI, CM and/or SM, whose surgical treatment was characterized by a large craniectomy with the patient in the sitting position, tonsillectomy, large opening of the fourth ventricle and duraplasty with creation of a large artificial cisterna magna. A significant upward migration of the posterior fossa structures was detected by postoperative magnetic resonance imaging.

Letter to the Editor: Syringomyelia

Letter to the Editor: Syringomyelia

Histopathological Investigation of Syringomyelia in the Cavalier King Charles Spaniel

Syringomyelia (SM) in Cavalier King Charles spaniels (CKCSs) is identified commonly on magnetic resonance images and is sometimes associated with clinical signs of pain and cervical hyperaesthesia. However, the mechanism by which SM develops in this breed has not been fully elucidated and the associated effects on spinal cord structure have not been reported previously. The aims of this study were to describe changes found in the spinal cord of CKCSs, to compare findings between symptomatic and asymptomatic dogs and to determine whether syrinx formation was associated with tissue destruction. Anomalies of the central canal were found in all specimens and many dogs had grossly visible fluid-filled cavities within the spinal cord. Prominent microscopical findings were spongy degenerative changes associated with neuronal necrosis and Wallerian degeneration. The ependyma was discontinuous in many specimens, notably in symptomatic individuals, and there was evidence of angiogenesis and fibrous tissue proliferation around blood vessels adjacent to syrinx cavities. Compared with two different samples of the normal dog population, dogs with syrinxes had significantly less grey matter, although this decrease was associated with generalized loss of spinal cord area. Therefore, SM is associated with degenerative changes in the spinal cord and may develop through primary disruption of ependymal integrity followed by vascular hypertrophy and proliferation. Glial and fibrous proliferation appears to be associated with expression of clinical signs.

Influence of head positioning on the assessment of Chiari-like malformation in Cavalier King Charles spaniels

Chiari-like malformation (CM) is almost omnipresent in the Cavalier King Charles spaniels (CKCS), often leading to syringomyelia (SM). Morphometric studies have produced variable results concerning relationship between the brain parenchyma...

An efficacy analysis of posterior fossa decompression techniques in the treatment of Chiari malformation with associated syringomyelia

A retrospective study of the efficacy of posterior fossa decompression (PFD) was carried out in 132 patients with Chiari malformation (CM) with associated syringomyelia (SM). Of these 132 patients, 69 received extended PFD (large craniotomy group), and the other 63 patients received only local PFD (small craniotomy group). At the short-term postoperative evaluation (1–4 weeks) the extended PFD appeared to be more effective than the local PFD ( p < 0.05). However, there was no significant difference in long-term analysis (6 months–11 years) ( p > 0.05). In the large craniotomy group, there was no difference between the short-term and long-term efficacy ( p > 0.05). However, in the small craniotomy group, long-term efficacy clearly improved ( p < 0.05). Furthermore, patients who had undergone local PFD exhibited more obvious radiological improvement of SM ( p < 0.05) and fewer postoperative complications compared to patients undergoing extended PFD ( p < 0.05). Therefore, local PFD is preferable for the surgical treatment of CM with associated SM.

Diagnosis and microsurgical treatment of Chiari malformation

Objective To study the diagnosis and the microsurgical treatment for Chiari malformation( CM ).Methods The clinical data of 50 cases of Chiari malformation were analyzed retrospectively,30 cases were combinated with syringomyelia,3 with cranial basal invagination referred to dens of axis.Results 50 cases were followed up for an average 35 months.According to Tator's standard,the curative effect was excellent in 36,good in 12 and bad in 2 patients.The effective rate was 96％.The cavities in spinal cords reduced in 21 cases,disappeared in 7.Conclusion Limited posterior fossa decompression with reconstruction of cistern magna is a effective method for treatment of CM ; CM with cranial basilar invagination referred to dens of axis treated firstly by anterior decompression of odontoidectomy via oral approach may be an optimal selection. Key words: Chiari malformation ; Syringomyelia ; Diagnosis ; Microsurgery ;

Endoscopic foramen magnum decompression of Chiari malformation

Objective To investigate the methods and effectiveness to treat Chiari malformation with the surgical decompression of the foramen magnum under endoscope. Method 23 cases with Chiari malformation.(without atlanto- axialdislocation and basilar invagination) diagnosed by magnetic resonance imaging( MRI)were operated with the surgical decompression of the foramen magnum under the endoscope. Results 23 cases were followed- up 0. 5 -3. 0, years after operation, all the symptoms and signs were remarkably relieved after the operation. No complications was found. In 16 cases with spinal cavities,7 cases spinal cavities disappeared and scases deflated,l case no evident change. Conclusions The endoscope -assisted decompression of the foramen magnum is a safe and effective surgical method to treat Chairi malformation. Key words: Endoscopes; Chiari malformation; Tonsillar herniation malformation; Syringomyelia; Foramen magnum decompression

Current Opinions for Treatment of Symptomatic Hindbrain Herniation or Chiari Type I Malformation

T b d a a S e e m s p b h w T T he hindbrain herniation syndrome, often referred to as the Chiari I malformation, is a disorder that traditionally has been defined as downward herniation of the cerebellar onsils through the foramen magnum more than 4–5 mm on agittal magnetic resonance imaging (MRI) (2, 5, 6, 10, 13, 14). his anomaly is associated with syringohydromyelia (SHM) in 5%–68% of cases (12). It occurs in conjunction with osseous bnormalities of the craniovertebral junction. This is distinguished rom the more familiar Chiari II malformation, which is present at irth and consists of downward herniation of the cerebellum and edulla into the spinal canal and is associated with complex nomalies such as aqueductal forking, polymicrogyria, and myeldysplasia. Changes in cerebrospinal fluid (CSF) dynamics conribute to the symptoms and the clinical syndrome characterized y the occipital Valsalva-type headaches, lower cranial nerve bnormalities, and spinal cord myelopathy that may be overshadwed by the syringohydromyelia.

Distribution of syringomyelia along the entire spinal cord in clinically affected Cavalier King Charles Spaniels

Chiari-like malformation (CM) and syringomyelia (SM) is an important disease complex in the Cavalier King Charles Spaniel (CKCS) but data about the anatomical distribution of SM along the spinal cord are lacking in veterinary medicine. The objective of this study was to define the anatomic distribution of SM in CKCS clinically affected by CM/SM. Magnetic resonance imaging (MRI) of the brain and the entire spinal cord of 49 dogs was performed and different morphological parameters compared. Syrinx formation was present in the C1-C4 region and in other parts of the spinal cord. The maximal dorsoventral syrinx size can occur in any region of the spinal cord and the total syrinx size was positively correlated with age. Seventy-six per cent of CKCS with a cranial cervical syrinx also have a syrinx affecting more caudal spinal cord regions. MRI restricted to the cervical region may underestimate the extent of SM and the severity of the disease process in the majority of dogs.

Spinal Subarachnoid Space Pressure Measurements in an In Vitro Spinal Stenosis Model: Implications on Syringomyelia Theories

Full explanation for the pathogenesis of syringomyelia (SM), a neuropathology characterized by the formation of a cystic cavity (syrinx) in the spinal cord (SC), has not yet been provided. It has been hypothesized that abnormal cerebrospinal fluid (CSF) pressure, caused by subarachnoid space (SAS) flow blockage (stenosis), is an underlying cause of syrinx formation and subsequent pain in the patient. However, paucity in detailed in vivo pressure data has made theoretical explanations for the syrinx difficult to reconcile. In order to understand the complex pressure environment, four simplified in vitro models were constructed to have anatomical similarities with post-traumatic SM and Chiari malformation related SM. Experimental geometry and properties were based on in vivo data and incorporated pertinent elements such as a realistic CSF flow waveform, spinal stenosis, syrinx, flexible SC, and flexible spinal column. The presence of a spinal stenosis in the SAS caused peak-to-peak cerebrospinal fluid CSF pressure fluctuations to increase rostral to the stenosis. Pressure with both stenosis and syrinx present was complex. Overall, the interaction of the syrinx and stenosis resulted in a diastolic valve mechanism and rostral tensioning of the SC. In all experiments, the blockage was shown to increase and dissociate SAS pressure, while the axial pressure distribution in the syrinx remained uniform. These results highlight the importance of the properties of the SC and spinal SAS, such as compliance and permeability, and provide data for comparison with computational models. Further research examining the influence of stenosis size and location, and the importance of tissue properties, is warranted.

Mechanisms of neuropathic pain: A multimodal approach combining event-related potentials, psychophysics and spinal diffusion tensor imaging in syringomyelia

Mechanisms of neuropathic pain: A multimodal approach combining event-related potentials, psychophysics and spinal diffusion tensor imaging in syringomyelia