Defining, diagnosing, clarifying, and classifying the Chiari I malformations.

PURPOSE: Chiari malformations (CM) have been traditionally classified into four categories: I, II, III, and IV. In light of more recent understandings, variations of the CM have required a modification of this classification. METHODS: This article discusses the presentation, diagnostics, and treatment of the newer forms of hindbrain herniation associated with the CM type I. RESULTS: The CM 1 is a spectrum that includes some patients who do not fall into the exact category of this entity. CONCLUSIONS: While CM have been categorically recognized as discrete and individual conditions, newer classifications such as CM 0 and CM 1.5 exhibit some degree of continuity with CM 1; however, they require distinct and separate classification as symptoms and treatments can vary among these clinical subtypes.

Currarino syndrome: does the presence of a genetic anomaly correlate with a more severe phenotype? A multicentre study.

BACKGROUND/PURPOSE: Currarino syndrome (CS) phenotype, initially described as the triad of hemisacrum, anorectal malformation (ARM) and presacral mass, can be extremely variable. The triad is often incomplete and 3 main CS phenotypical subtypes have been described: Complete, Mild and Minimal. Various associated malformations are often present. Mutations in the MNX1 gene are the main genetic background of CS, although they are not present in almost half of the cases. Aim of our study is to analyze the distribution of the 3 CS subtypes and the incidence of associated malformations in a large sample of patients and to add information about the role of the genetic testing in guiding the diagnostic and prognostic evaluation of CS patients. METHODS: A multicentre retrospective data collection was performed. CS patients' phenotype was accurately analyzed according to a diagnostic-therapeutic standardized data collection sheet. The distribution of the three CS types and the frequency of each associated malformation were calculated. The phenotype of the patients with a known genetic anomaly was compared to the phenotype of the population with no genetic diagnosis, in order to determine whether the presence of a known genetic defect could correlate with a more severe CS phenotype. RESULTS: Data from 45 patients were analyzed. Twenty patients (44.5%) presented a Complete CS type, 19 (42.2%) a Mild CS and 6 (13.3%) a Minimal CS. In addition to the classical triad elements, 38 (84.5%) patients showed associated anomalies. The group of patients who resulted positive for a MNX1 mutation comprised a higher number (56.5%) of Complete CS cases than the group of patients that did not carry any MNX1 mutation (13%) (p = 0.0085). We could not find any relationship between CS subtype and the number of associated anomalies (p = 0.5102). CONCLUSIONS: The presence of a MNX1 mutation seems to correlate with a more severe CS phenotype. MNX1 seems the main responsible for the expression and the severity of the CS triad, while the associated anomalies appear to be prevalently determined by genes sited on different loci. A thorough multidisciplinary diagnostic overview of CS patients should always include genetic counseling and analysis, both in postnatal and prenatal settings. TYPE OF STUDY: Retrospective Study. LEVEL OF EVIDENCE: II.

Syringomyelia: a practical, clinical concept for classification.

BACKGROUND: The term syringomyelia describes many pathogenetically different disorders, and a variety of attempts to group these based on different criteria have been proposed in the literature. As a consequence a lack of consensus regarding classification and terminology exists. This inconsistency extends to the ICD-10 classification of diseases in regards to syringomyelia (G95.0) and hydromyelia (Q06.4). We propose a new unifying concept for classification that also incorporates diagnostics and treatment. METHODS: The PubMed online database was used to gain a general overview of the existing pathogenetic theories in relation to syringomyelia. Illustrative cases at our department were included and similar cases of the literature were found using the PubMed database. All material was reviewed with main focus on the classification and terminology used. RESULTS: Despite syringomyelia (G95.0) and hydromyelia (Q06.4) existing as independent ICD-10 entities, we have shown that the use of classifying terminology for fluid-filled cavities in the spinal cord is indiscriminate and inconsistent. Even though a general agreement on the believed pathogenetic mechanism exists, and the general treatment methods are used in accordance with this mechanism, the terminology fails to function as a simple and universal link between theory and treatment. CONCLUSIONS: We propose a new causal concept for an ICD classification with syringomyelia (G95.0) as the only describing terminology, thus abandoning the use of hydromyelia (Q06.4). Syringomyelia is divided into five subgroups according to the associated pathologies. The classification is based on applied diagnostics and serves as a clinical guidance for treatment.

[Diagnosis of syringomyelia and its classification on the basis of symptoms, radiological appearance, and causative disorders].

Although it is easier to accurately diagnose syringomyelia with the advent of magnetic resonance (MR) imaging, syringomyelia still poses challenges to clinicians because of its complex symptomatology, uncertain pathogenesis and multiple treatment options. Here, we propose criteria for classification of syringomyelia not related to those associated with spinal intramedullary tumors. The classification aims to distinguish between the presyrinx state and syringomyelia, between asymptomatic and symptomatic syringomyelia and to clarify the associated disorders such as Chiari malformations, spinal arachnoiditis and spinal cord trauma. Diagnostic criteria for Chiari I and II malformations with MR imaging were also defined. Several hypotheses proposed to explain the pathogenesis of syringomyelia associated with Chiari I malformation were reviewed. A questionnaire survey on syringomyelia based on the proposed criteria conducted between November 2009 and April 2010 in Japan revealed that 160 (22.6%) of the 708 patients were asymptomatic. Chiari I malformation was the most frequent causative disorder (48.3%), followed by spinal arachnoiditis (15.8%). The proposed criteria for classification of syringomyelia will facilitate a nationwide survey of syringomyelia in Japan. Such a survey will inform us of its prevalence and prognosis more precisely, and enable us to build a reliable database that may help determine the optimal treatment for the disease in the future.

Pediatric Chiari malformation Type 0: a 12-year institutional experience.

OBJECT: In 1998 the authors identified 5 patients with syringomyelia and no evidence of Chiari malformation Type I (CM-I). Magnetic resonance imaging of the entire neuraxis ruled out other causes of a syrinx. Ultimately, abnormal CSF flow at the foramen magnum was the suspected cause. The label "Chiari 0" was used to categorize these unique cases with no tonsillar ectopia. All of the patients underwent posterior fossa decompression and duraplasty identical to the technique used to treat patients with CM-I. Significant syrinx and symptom resolution occurred in these patients. Herein, the authors report on a follow-up study of patients with CM-0 who were derived from over 400 operative cases of pediatric CM-I decompression. METHODS: The authors present their 12-year experience with this group of patients. RESULTS: Fifteen patients (3.7%) were identified. At surgery, many were found to have physical barriers to CSF flow near the foramen magnum. In most of them, the syringomyelia was greatly diminished postoperatively. CONCLUSIONS: The authors stress that this subgroup represents a very small cohort among patients with Chiari malformations. They emphasize that careful patient selection is critical when diagnosing CM-0. Without an obvious CM-I, other etiologies of a spinal syrinx must be conclusively ruled out. Only then can one reasonably expect to ameliorate the clinical course of these patients via posterior fossa decompression.

Surgical outcomes of foramen magnum decompression for syringomyelia associated with Chiari I malformation: relation between the location of the syrinx and body pain.

BACKGROUND: There have been few reports about the relation between the morphology of syrinxes and body pain in syringomyelia associated with Chiari I malformation. To investigate this phenomenon, the relation between the location of the syrinx and body pain before and after foramen magnum decompression (FMD) were evaluated. METHODS: The subjects were 20 patients with Chiari I malformation associated with syringomyelia who underwent FMD. The morphology of the syrinxes was classified into three types - enlarged type, which was a distended syrinx at the central spinal cord; deviated type, which was a deviated syrinx posterolaterally within the spinal cord; central type, which was a small syrinx at the central canal of the spinal cord - based on axial magnetic resonance imaging (MRI). Preoperative and postoperative clinical symptoms and the body pain were evaluated by the Japanese Orthopaedic Association (JOA) score and a visual analogue scale (VAS) prospectively. RESULTS: Preoperative and postoperative JOA scores showed no statistically significant differences between the three syrinx types. Intensity of body pain evaluated by the VAS showed that patients with a deviated-type syrinx on pre- and postoperative MRI tended to be associated with more intense pain than the other two types. CONCLUSIONS: It was indicated that pain before and after surgery is more intense when the syrinx is deviated toward the spinal dorsal horn as seen on MRI.

Adult syringomielia. Classification, pathogenesis and therapeutic approaches.

Syringomyelia is characterized by the presence of cystic cavities inside the spinal cord, with an incidence estimated of 8.4 new cases/year/100 000 people. The cavities are usually located inside the cervical cord, although they can extend upwards and/or downwards. The underlying cause of all types of syringomyelia is an alteration in physiologic cerebrospinal fluid (CSF) flow dynamics. Four different main types may be described in descending order of frequency: associated with Chiari I malformations, associated with vertebral trauma, associated with basilar invagination and associated with hydrocephalus. Conservative treatment is not recommended as the surgical procedure stops the progress of the disease with clinical improvement being the rule. Early surgical treatment is highly recommended before the establishment of gross neurological deficits occurs. Treatment is urged in case of clinical deterioration or when the follow-up MRI studies show increase in size and extension of the syringomyelic cavity. The first step in the surgical treatment is a precise diagnosis of its etiology to direct the treatment to the underlying cause. Treatment directed to normalize CSF flow homeostasis should be case tailored. Surgical measures that aim to reconstruct the continuity of the subarachnoid space at the site of the block are the first treatment option. Shunting is advocated when reestablishment of the pathways proves impossible or as a second procedure.

Evaluating congenital spine deformities for intraspinal anomalies with magnetic resonance imaging.

SUMMARY: The incidence of intraspinal abnormalities associated with congenital spinal anomalies as detected by magnetic resonance imaging (MRI) is becoming better defined. In this study, 41 nonrandomized children with congenital spinal deformities (excluding myelomeningocele) who underwent complete MR evaluation were reviewed. Of the 41 congenital spinal deformities, 37 demonstrated congenital scoliosis, with failure of formation in 19, failure of segmentation in 4, and mixed defects in 14. The remaining four deformities were cases of congenital kyphosis. Thirteen patients with congenital spine anomalies were noted to have intraspinal abnormalities identified by MRI: tethered cord in 12 patients, syringomyelia in 3 patients, and diastematomyelia in 5 patients. Of the 12 patients with tethered cord, 2 patients had neurologic deficits. Urorectal anomaly was one of the most common associated findings (15%). Considering an incidence of intraspinal anomalies of 31% and as clinical manifestations may not be initially detectable, MRI is recommended in patients with congenital spinal deformity as part of the initial evaluation even in the absence of clinical findings.

Classification of syringomyelia.

Syringomyelia poses special challenges for the clinician because of its complex symptomatology, uncertain pathogenesis, and multiple options of treatment. The purpose of this study was to classify intramedullary cavities according to their most salient pathological and clinical features. Pathological findings obtained in 175 individuals with tubular cavitations of the spinal cord were correlated with clinical and magnetic resonance (MR) imaging findings in a database of 927 patients. A classification system was developed in which the morbid anatomy, cause, and pathogenesis of these lesions are emphasized. The use of a disease-based classification of syringomyelia facilitates diagnosis and the interpretation of MR imaging findings and provides a guide to treatment.

Presentation and management of hydromyelia in children with Chiari type-II malformation.

Hydromyelia in patients with myelomeningocele and Chiari-II malformation is a relatively frequent finding on MRI studies. However, not all children develop symptoms from the hydromyelia that requires treatment. Furthermore, treatment of hydromyelia in spina bifida patients is rather complex due to the associated malformations. The authors retrospectively analyzed 231 MRI studies carried out on spina bifida patients who presented neurological deterioration. Hydromyelia was found in 48.5% of the patients. Forty-five children with severe hydromyelia required treatment. These patients were first divided into 2 groups: those with holocord hydromyelia, and those with a segmental lesion. Fifteen patients presented symptoms characteristic of symptomatic Chiari-II malformation: neck rigidity; swallowing difficulty; pain in the upper extremeties; weakness or spasticity in the upper extremeties. Eighteen patients presented symptoms typical of the tethered cord syndrome: scoliosis; worsening bladder and/or bowel function; pain in the lower extremeties; weakness or spasticity in the lower extremeties. Twelve patients presented a mixed-type symptomatology. These patients subsequently underwent posterior cervical decompression, tethered cord release or insertion of a hydromyelia-pleural shunt according to the type of presenting symptoms and to the extent of the hydromyelic lesion. A pattern of successful treatment was identified for each type of presenting clinical and radiological picture. This has allowed the authors to determine an algorithm for optimal treatment of hydromyelia associated with Chiari-II malformation and myelomeningocele, which is proposed here.

[Surgical treatment of syringomyelia].

Eighty cases of surgically treated syringomyelia were retrospectively reviewed. The cases were classified into following 4 types, type 1: syringomyelia with Chiari malformation (54 cases), type 2: syringomyelia with basal arachnoiditis (15 cases), type 3: syringomyelia with an obstruction of the foramen Magendie (1 case), and type 4: syringomyelia with spinal arachnoiditis (14 cases). Foramen magnum decompression (FMD) was performed in patients with type 1, in type 2 fourth ventricle-subarachnoid shunt was additionally performed. Gardner's operation was performed in patients with type 3. Syrinx-peritoneal shunt was performed in patients with type 4. Surgical procedures for syringomyelia which we selected were thought to be appropriate, based on postoperative syrinx collapse rate in MRI. However, postoperative clinical course was much different in each type of syringomyelia after the collapse of syrinx had been equally achieved. Neurological disorders were stopped in deterioration after surgery in all cases of type 1. However, motor weakness was still deteriorated in half cases of type 2, and in 60% of type 4. When clinical severity of the patients with type 1 and 2, based on the distribution of dissociated sensory loss and motor weakness, were classified into 5 grades. The rate of improvement of patient's symptoms and signs was higher in the lower grades. We concluded that a surgical treatment for syringomyelia was essentially a preventive one, therefore it should be done in early stage of disorders.

Chiari I malformation: classification and management.

Considerable debate exists about which surgical options are best for the management of the Chiari I malformation. We present a classification system for the Chiari I malformation that improves the prediction of outcome and guides the selection of surgical treatment. Twenty-seven adult patients with Chiari I malformations were grouped on the basis of the presence of signs and symptoms of brain stem compression, syringomyelia, or both. To objectively assess changes in clinical status postoperatively, a scale was developed to quantify the signs and symptoms, which were statistically analyzed by the paired t test. Five patients were asymptomatic and underwent no treatment. Ten patients had symptoms of brain stem compression without associated syringomyelia and underwent brain stem decompression, including anterior decompression in one patient with basilar invagination; all 10 patients had significant improvement at 4-year mean follow-up visits (P < 0.0001). In 12 patients with syringomyelia, 5 were symptomatic from syringomyelia only, 6 were symptomatic from both brain stem compression and syringomyelia, and 1 was symptomatic from brain stem compression only. The median length of symptoms before presentation was longer for patients with syringomyelia than for patients without (2 yr versus 9 mo; P < 0.025); the mean follow-up was 4 years. Surgical procedures included posterior brain stem decompression in 12 patients, plugging of the obex in 7, and placement of syringosubarachnoid shunts in 7, a syringopleural shunt in 1, and fourth ventricular stents in 2. In the 12 patients with syringomyelia, symptoms from brain stem compression dramatically improved with surgical decompression (P < 0.025), whereas symptoms from syringomyelia less dramatically improved or stabilized. The slight improvement or stabilization of syrinx symptoms represents a successful result, given the documented progressive nature of syringomyelia in this group. We conclude that surgical treatment for the Chiari I malformation can stabilize or slightly improve the symptoms attributed to syringomyelia and dramatically relieve the symptoms of brain stem compression. Furthermore, early diagnosis and treatment are critical in obtaining the best outcome for the patient.

Introduction of a score system for the clinical evaluation of patients with spinal processes.

To facilitate statistical analysis of the clinical course of patients with spinal lesions such as tumours, dysraphic malformations, inflammation, or syringomyelia, we have developed a score system for each of the following symptoms and signs: sensory deficits, dysaesthesiae, pain, motor weakness, gait, bladder and bowel function. For each a score between 0 and 5 is given. The grading is designed in such a way that levels of functional significance receive separate scores: 0 = no function, 1 = severely disabled, 2 = disabled, 3 = severely compromised but function preserved, 4 = slightly compromised, and 5 = normal function. In general, scores between 0 and 2 indicate insufficient functional capacity and an unsatisfactory condition. Scores between 3 and 5 represent levels of function which should be the aim of treatment. We have used this scoring system for evaluation of almost 500 patients with spinal lesions both retrospectively and prospectively with good results in terms of reproducibility and validity.

Foraminal syringomyelia: suggestion for a grading system.

The standard treatment of foraminal syringomyelia includes foramen magnum decompression and duraplasty. Improvement or stabilization of the disease are achieved in most of cases. However, at least one third of patients are reported to receive little or no benefit. In this paper we retrospectively reviewed a series of 40 consecutive foramen magnum decompressions in order to identify the possible pre-operative outcome predictors. Based on clinical evolution, neurological impairment and radiological features, a scale of severity was fixed and retrospectively tested. A pre-operative score was obtained for each patient and was correlated with the surgical results. Then a four level grading system was derived. All grade I and grade II patients achieved good results (improvement or stabilization), whereas grade III patients showed intermediate behaviour and grade IV invariably worsened. On this basis, surgical results of foramen magnum decompression might be further improved provided that a careful pre-operative selection is made.

Syringomyelia: a neurological and surgical spectrum.

Because of the variation in the natural history, anatomy, surgical treatment, and follow-up periods reported to date, very few firm conclusions can be drawn regarding syringomyelia. With the advent of magnetic resonance scanning, cases of syringomyelia are being detected earlier and a better understanding of the disease has been facilitated. The authors report their personal experiences with 21 patients followed for 5-20 years. No single surgical procedure appears to predictably remedy any syrinx for more than a brief period of several years. Complete collapse of the syrinx does not eradicate all symptoms. Direct treatment of the syrinx makes intuitive sense for those syrinxes that do not communicate with the fourth ventricle. On the other hand, for syrinxes that are likely to communicate with the fourth ventricle, shunting of the ventricular system, particularly where ventriculomegaly exists (i.e., any degree of radiographic evidence of ventricular enlargement), should be considered initially. Procedures such as posterior fossa decompression may be necessary as dictated by the neurological condition of the patient. In the authors' experience, shunting procedures provided better improvement, with longer duration of improvement than with posterior fossa decompression. The timing and surgical details of posterior fossa decompression remain to be elucidated.

[Clinically manifest or silent primary and secondary syringomyelia. The magnetic resonance findings]. / Siringomielie primitive e secondarie a clinica manifesta o silente. Rilievi con Risonanza Magnetica.

The MR scans were retrospectively reviewed of 40 patients who had been diagnosed as having syringomyelia. Our results demonstrate that syringomyelia can be found in asymptomatic patients as well as in many with atypical symptomatology. Our study stresses MR efficacy in investigating this pathologic condition. As a matter of fact, MR allowed us to visualize the cavity, its extension, the eventual association with Arnold Chiari type-I malformation and/or syringobulbia. In all cases cord enlargement and the presence of septations could also be demonstrated. In most cases the possible pathogenesis of syringomyelia could also be supposed.