Syringomyelia: cyst measurement by magnetic resonance imaging and comparison with symptoms, signs and disability

Assessment of patients with a Chiari malformation type I

Introduction

The prevalence of Chiari malformation type I (CM-I) has been estimated as up to 1% of the general population. The majority of patients are asymptomatic and usually do not need treatment. Symptomatic patients, and some asymptomatic patients with associated conditions, may benefit from further assessment and treatment.

Research question

The aim of this review was to describe the clinical and radiological assessment of patients presenting with a CM-I.

Material and methods

A literature search was performed using the PubMed and Embase databases focused on clinical assessment and imaging techniques used to diagnose CM-I.

Results

Following a complete clinical evaluation in patients with symptomatic CM-I and/or radiologically significant CM-I (tonsillar impaction, resulting tonsillar asymmetry and loss of CSF spaces), MRI of the brain and whole spine enables an assessment of the CM-I and potential associated or causative conditions. These include hydrocephalus, syringomyelia, spinal dysraphism, and tethered cord. Flow and Cine MRI can provide information on CSF dynamics at the craniocervical junction, and help in surgical decision-making. Hypermobility or instability at the upper cervical and craniocervical junction is less common and can be measured with CT imaging and flexion/extension or upright MRI.

Discussion and conclusion

The majority of CM-I detected are incidental findings on MRI imaging of brain or spine, and do not require intervention. Once a radiological diagnosis and concern has been raised, clinical assessment by an appropriate specialist is required. A MRI brain and cervical spine is indicated in all radiologically labelled CM-I. In symptomatic patients or cases of radiologically significant CM-I, MRI of the brain and entire spine is indicated. Further investigations should be tailored to individuals’ needs.

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A CM-I assessment should include a history and examination and a referral to a specialist.

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MRI of the brain and spine enables an assessment of the CM-I and potential associated conditions.

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Flow and Cine MRI can help in surgical decision-making.

Mechanical quantitative sensory testing in cavalier King Charles spaniels with and without syringomyelia

BACKGROUND

Syringomyelia (SM) is a debilitating condition in the cavalier King Charles spaniel (CKCS) that results in neuropathic pain and diminished quality of life. Von Frey aesthesiometry (VFA) is a method of mechanical quantitative sensory testing that provides an objective sensory threshold (ST) value and can be used to quantify neuropathic pain (NP) and monitor response to therapy. The utility of VFA has been previously established in client-owned dogs with acute spinal cord injury but the technique has not been evaluated in dogs with SM. The goal of this study was to evaluate ST, as determined by VFA, in dogs with and without SM, to assess the utility of VFA in quantifying NP in SM-affected dogs. We hypothesized the SM-affected CKCS would have lower ST values, consistent with hyperesthesia, when compared to control CKCS. Additionally, we hypothesized that ST values in SM-affected dogs would be inversely correlated with syrinx size on MRI and with owner-derived clinical sign scores.

RESULTS

ST values for the thoracic and pelvic limbs differed significantly between the SM-affected and control CKCS (p = 0.027; p = 0.0396 respectively). Median ST value (range) for the thoracic limbs was 184.1 g (120.9-552) for control dogs, and 139.9 g (52.6-250.9) for SM-affected dogs. The median ST value (range) for the pelvic limbs was 164.9 g (100.8-260.3) in control dogs and 129.8 g (57.95-168.4) in SM-affected dogs. The ST values in SM-affected dogs did not correlate with syrinx height on MRI (r = 0.314; p = 0.137). Owner-reported clinical sign scores showed an inverse correlation with pelvic limb ST values, where dogs with lower ST values (hyperesthesia) were reported by their owners to display more frequent and severe clinical signs (r = - 0.657; p = 0.022).

CONCLUSION

ST values were lower in SM-affected CKCS compared to control dogs, suggesting the presence of neuropathic pain. Dogs with lower ST pelvic limb values were perceived by their owners to have more severe clinical signs classically associated with SM. Our results suggest that VFA might offer quantitative assessment of neuropathic pain in SM-affected dogs and could be useful for monitoring response to therapy in future clinical studies.

Association of increased body mass index with Chiari malformation Type I and syrinx formation in adults

Object

In this paper the authors describe an association between increased body mass index (BMI) and Chiari malformation Type I (CM-I) in adults, as well as its relationship to the development of syringomyelia.

Methods

In the period between January 2004 and December 2011, the senior author reviewed the data for all CM-I patients with or without syringomyelia and neurological deficit. Analyzed factors included clinical status (headaches and neurological signs), radiological characteristics of syringomyelia (diameter and vertical extent of syrinx), BMI, and relationship of age to BMI, syrinx diameter, and vertical extent of syrinx.

Results

Sixty consecutive adults had CM-I, 26 of whom also had syringomyelia. The mean BMI among all patients was 30.35 ± 7.65, which is Class I obesity (WHO), and was similar among patients with or without syringomyelia. Extension of the vertical syrinx was greater in overweight patients (p = 0.027) than in those with a normal body weight. Evidence of de novo syrinx formation was found in 2 patients who gained an average BMI of 10.8 points. After repeated decompression and no change in holocord syrinx width or vertical extent, a reduction in the syrinx was seen after BMI decreased 11.7 points in one individual. No correlation was found between patient age and BMI, age and vertical extension of the syrinx, and age and diameter of the syrinx.

Conclusions

An association between increased BMI and CM-I in adults was recognized. Gaining weight may influence the de novo creation of a syrinx in adults who previously had minimally symptomatic or asymptomatic CM-I, and reducing weight can improve a syrinx after unsuccessful surgical decompression. Therefore, a reduction in body weight should be recommended for all overweight and obese patients with CM-I.

Preuntethering and postuntethering courses of syringomyelia associated with tethered spinal cord

BACKGROUND

There has been controversy regarding the management of syringomyelia associated with tethered spinal cord. Previous reports on the topic have included only a small number of patients, considered open/closed spinal dysraphism together, or had a short follow-up.

OBJECTIVE

To review a uniform group of patients with syringomyelia associated with tethered cord and treated mainly by untethering alone.

METHODS

Of the 135 patients operated on for closed spinal dysraphism between 2003 and 2008, 33 patients with preoperative syringomyelia were identified. The preoperative/postoperative clinical data and syrinx index (ratio of the syrinx area and the cord area) were retrospectively reviewed. The syrinx index of each patient was plotted as an individual graph to outline the temporal change of the syrinx before and after untethering surgery.

RESULTS

Five patients showed symptom progression during the preoperative period, and 4 of the 5 had an additional magnetic resonance imaging before the operation that showed progression of the syringomyelia. Postoperatively, 31 of 32 patients (97%) who underwent postoperative follow-up imaging showed long-term stability or a decrease in the syrinx index. Four symptomatically stable patients showed a transient increase in the syrinx index during the initial postoperative 6 months, which later decreased spontaneously. In 1 patient with retethering, the syrinx index increased 6 months before the onset of new urinary symptoms.

CONCLUSION

Untethering alone may be sufficient for the management of syringomyelia associated with tethered cord. A transient increase in the syrinx index during the initial postoperative period may be observed without additional surgery if patients are symptomatically stable.

Treatment of terminal syringomyelia in association with tethered cord syndrome: clinical outcomes with and without syrinx drainage

Object

Current use of magnetic resonance (MR) imaging has led to increased awareness of the frequency of terminal syringomyelia in patients with tethered cord syndrome. However, that the surgical treatment of terminal syringomyelia is necessary remains unclear.

In this study the authors attempted to assess the clinical impact, if any, brought after syrinx decompression on the clinical outcome of tethered cord syndrome.

Methods

They randomly assigned 30 cases of pediatric tethered cord into two treatment groups: those in whom an untethering procedure was performed (Group I) and those in whom this procedure was combined with syrinx decompression (Group II). The 1-year follow-up clinical results obtained in the two groups, in correlation with MR imaging findings, were compared to evaluate the benefit of added syrinx drainage.

Clinical follow-up evaluation revealed that surgical drainage of the syrinx, when combined with spinal cord untethering, resulted in better outcomes in terms of resolution of sensory deficits (p = 0.036) and bladder dysfunction (p = 0.05). The improvement in clinical outcome correlated with the radiologically documented resolution of the syrinx cavity; however, response rates of symptoms differed for each tethering subgroup.

Conclusions

Preliminary results of this study indicated that terminal syringomyelia should be considered as a comorbidity that contributes to the clinical outcome of patients with tethered cord syndrome. A better clinical outcome is achieved following successful decompression of the syrinx in addition to untethering the spinal cord. These findings emphasize the importance of recognizing, evaluating, and treating this pathological entity.

Terminal syringomyelia in association with the tethered cord syndrome

OBJECTIVE

With the increasing use of magnetic resonance imaging, terminal syringomyelia (segmental cystic dilation of the caudal one-third of the spinal cord) in association with the tethered cord syndrome has become an appreciable finding. This study attempted to define the clinical significance of this associated pathological condition by describing its clinical and radiological characteristics and its contribution to the clinical status of patients with tethered spinal cords.

METHODS

Of 132 consecutive patients with tethered cord syndrome who presented to our department between 1990 and 1997, 32 patients with terminal syringomyelia were enrolled in this study. Clinical findings were correlated with syrinx morphological features, as defined using magnetic resonance imaging. Surgical treatment used two basic approaches, i.e., simple untethering or untethering with concurrent syrinx drainage.

RESULTS

Analysis of the neurological deficits established a contribution of segmental symptoms, which were correlated with the extension and dilation of the syrinx cavity. Magnetic resonance imaging scans revealed the frequency of sacral tethering (40.6%), the intramedullary paracentral position of the syrinx (75%), and disturbances in regional cerebrospinal fluid flow (42%). The clinical outcomes seemed to be correlated with syrinx shrinkage; all patients who experienced collapse of the cavity achieved better symptom resolution.

CONCLUSION

Radiologically significant terminal syringomyelia affects the clinical presentation of tethered cord syndrome, by increasing or inducing neurological deficits. Better clinical outcomes after syrinx decompression emphasize the importance of the recognition and treatment of this pathological condition.

[Correlations between clinical deficits, motor and sensory evoked potentials and radiologic aspects of MRI in malformative syringomyelia. 27 Cases]

Twenty-seven patients (15 males, 12 females, age range: 16-66 years) were admitted for malformative syringomyelia diagnosed on MRI with measures of syrinx extending and transverse diameter. Posterior tibial somatosensory evoked potentials (PT SEP), median (M SEP), trigeminal (V3 SEP), brain stem auditory evoked potentials (BEAP), cortical and cervical motor evoked potentials (MEP) were correlated with clinical and radiological findings. SEP abnormalities were not correlated with the duration of symptoms. PT SEP proved to be more sensitive than M SEP. MEP abnormalities were very frequent (87% of the cases), even without clinical motor deficits. Trigeminal SEP were more sensitive than BEAP which were not related to the presence of associated cranio-vertebral abnormalities. We found no significative relationship between clinical and radiological results. Moreover, there was a positive relationship between electrophysiological and radiological results: abnormal trigeminal SEP were detected in 85% of the patients with high cervical syringomyelia. In all cases, trigeminal SEP and MEP should be done in association with M and PT SEP as both of them detect subclinical evidence of spinal cord dysfunction in syringomyelia.

Posttraumatic syringomyelia: profound neuronal loss, yet preserved function

Posttraumatic syrinxes may extend many cord segments rostral to a spinal cord injury (SCI) and significantly dilate the spinal cord, yet few neurologic deficits may be noted. Careful physical examination may reveal ascending loss of pain and temperature without evident functional motor decline. We present a 49-year-old man with T4 paraplegia and a large posttraumatic syrinx who died 3 weeks after syringoperitoneal shunting. Neuropathologic study revealed a large bilateral syrinx cavity from T1 to C6 that tapered to a small unilateral syrinx at C2. Light microscopy of sections from T1 to C2 showed massive loss of intermediate to intermedio-lateral gray neurons and moderate reduction of motoneurons at T1 to C6 levels. Despite these findings, manual muscle testing results remained normal for wrist extensors and elbow extensors, and the patient continued to perform independent sliding board transfers. We conclude that this large progressive syrinx did not merely dissect neural elements apart but caused extensive neuronal damage. Loss of interneurons was evident in spinal segments with preserved strength and function. Possible mechanisms to explain the relatively minimal clinical deficits in view of the neuronal loss are discussed.

Utility of early postoperative MRI in hindbrain-related syringomyelia. A preliminary prospective study on five patients

We report a series of five patients operated on for hindbrain-related syringomyelia with posterior fossa decompression and duraplasty. In all cases an early postoperative MRI was performed (24-36 h after surgery). These images have been compared with the preoperative ones and with those obtained, 1, 3 and 6 months after operation. Both before and after surgery there was not always a tight correlation between clinical and MRI pictures. In all but one patient the early postoperative MR images showed a reduction of syrinx size and were as to those obtained later. We discuss the results observed in our small series and analyze the role of early postoperative MRI studies in patients with hindbrain-related syringomyelia.

Micturitional disturbance in syringomyelia

Micturitional histories and urodynamic studies were performed in 14 patients with syringomyelia. Eleven patients were revealed to have urinary symptoms including difficulty of voiding in 8, urinary retention in 3, nocturnal and diurnal urinary frequency in 3, urinary incontinence in 2, and sense of urgency and enuresis in one. These urinary symptoms appeared after 5.3 years (ranging from 2 months to 13 years) from the occurrence of the neurological symptoms. Urodynamic studies revealed detrusor hyperreflexia in 7, detrusor areflexia in 4, detrusor-sphincter dyssynergia in 4 and uninhibited sphincter relaxation in 2 patients. Analysis of the motor unit potentials of the external sphincter revealed 5 of 6 patients had high amplitude or polyphasic neurogenic changes. Supranuclear as well as nuclear types of parasympathetic and somatic nerve dysfunctions seemed to be responsible for micturitional disturbance in our patients with syringomyelia. During the follow-up period of 2 to 63 months, urinary symptoms gradually improved in 4 of 6 patients after syringosubarachnoid shunts and in 3 of 4 after alpha-adrenoreceptor blocking agents.

Scoliosis as the first sign of a cystic spinal cord lesion

We reviewed the cases of ten patients with scoliosis as the first sign of a cystic spinal cord lesion with the aim of identifying and studying early patient and curve characteristics. All patients were examined with magnetic resonance (MR) imaging of the brain and spinal cord and quantitative thermal testing (QTT). The mean Cobb angle was 22 degrees and the curves were right thoracic in seven patients, left thoracic in two, and left lumbar in one, when first seen for scoliosis. In six patients the cystic lesion was found in routine screening for syringomyelia, which is performed in all cases of congenital and juvenile scoliosis and in adolescent scoliosis before bracing. In four patients, it took up to 17 years following the initial diagnosis of scoliosis before neurologic deterioration warranted MR imaging, disclosing two Chiari I associated syrinxes and two cystic spinal cord tumors. QTT revealed a subclinically decreased sensation in two of the patients with no findings other than scoliosis. It also verified the decreased sensation in all patients in whom neurologic deterioration had complicated the clinical course of their scoliosis. More frequent spinal MR screening of patients with supposed juvenile or adolescent idiopathic scoliosis is indicated, regardless of curve type, to exclude a neurogenic cause. QTT documents subclinical as well as overt decreased sensation, and is valuable in the serial follow-up of these patients to monitor the progress or the response to treatment of the cystic lesion.

Surgery for hindbrain related syringomyelia

Syringomyelia is a condition with many possible causes, the commonest of which seems to be an abnormality at the foramen magnum. Such cases may be grouped under the heading of "Hindbrain related syringomyelia" and the principles of treatment for all such cases are largely similar. The commonest of these foramen magnum region abnormalities is hindbrain herniation which may be associated with a history of birth difficulties, a small posterior fossa, segmentation abnormalities of the cervical vertebrae or the base of the skull, arachnoiditis of the subarachnoid spaces, subarachnoid pouches, hydrocephalus and intracranial tumours or tumours partly blocking the foramen magnum. Other causes of syringomyelia include conditions which could be grouped under the heading of "non-hindbrain related syringomyelia", these mostly produce blockage of the spinal subarachnoid spaces, especially spinal "arachnoiditis" or meningeal fibrosis, including that secondary to traumatic paraplegia. Intraspinal tumours are sometimes cystic and some authors have included this association under the heading of syringomyelia. Syringomyelia of all kinds is almost always a surgical condition, the destructive forces are those of fluid distending the tissues. As a principle, treatment directed against the cause of the accumulation and the intracord propagation of the fluid by normalising the CSF pathways is more likely to be successful than drainage of the cavities. Drainage operations have an inevitable failure rate and a further incidence of complications attends myelotomy and the leaving of any drainage tube within the narrow confines of the spine. Correction of craniospinal pressure dissociation and re-establishment of a cisterna magna appears to be the most successful treatment strategy and is likely to be immediately and permanently successful in correcting not only the pressure problems such as long tract involvement and syringobulbia features but also in producing satisfactory clinical and radiological improvement in the syringomyelia. The recommended technique includes radical means to gain space at the foramen magnum by creating a large artificial cisterna magna, resecting part of the tonsils, preventing the descent of the cerebellum and avoiding the use of space occupying or fibrosis producing dural grafts. Because the pathogenesis of the cavities remains in doubt, the method by which this treatment stratagem is effective is unclear. It may be that change in the closure conditions of parts of the neuraxis, i.e., alteration in the capacitance and consequent change in pulsation characteristics afforded by the decompression may be the factor which predicates success. Surgical management of hindbrain related syringomyelia is not easy, there are hazards associated with operation, hydrocephalus demands priority in it's management.(ABSTRACT TRUNCATED AT 400 WORDS)

The relation between functional deficits, motor and sensory conduction times and MRI findings in syringomyelia

Opinions about the relation between the dimensions of the syrinx and the severity and distribution of symptoms in patients with syringomyelia are controversial. Therefore, this study investigates the relation of clinical symptoms, a disability score, quantified (1- and 2-dimensional) radiological findings (magnetic resonance imaging, MRI) and electrophysiological data (somatosensory and motor evoked potentials) in 22 patients with syringomyelia. There was a close relation between clinical symptoms and electrophysiological data. By both electrophysiological methods subclinical deficits could be detected. Furthermore, the results disclosed that the clinical symptoms, the degree of disability and the duration of the disease are not related to the dimensions of the syrinx or the electrophysiological results obtained by investigating the long ascending and descending spinal tracts of the lower limbs. Our findings suggest that, besides the syrinx, other factors not directly visible in the MRI are responsible for the development and progress of clinical symptoms.

Natural history and postsurgical outcome of syringomyelia

The surgical treatment of syringomyelia is still debatable and the result are often poor. Several surgical procedures, based on various proposed etiopathologies, have been developed but in many cases have proved completely ineffective. We have evaluated the follow-up of 69 syringomyelic patients, some operated on, some not, in the search for clues to the management of the disease. For this purpose we devised a rating system, which we describe. 31 patients underwent surgery while 38 received no treatment. We found that half of the patients deteriorated, whether they were operated on or not; only 1 in 5 improved and the rest remained stable. For surgical treatment to be successful, the disease must be in rapid evolution but without definite paraparesis.

The natural history and results of surgery in 50 cases of syringomyelia

In recent years, new neuroimaging techniques have revived interest in syringomyelia with respect to indications and results of surgery. Fifty patients, 36 of whom underwent surgery, have been reviewed. All patients but 3 underwent a new clinical assessment and 33 of them were also neurophysiologically investigated. In approximately one-third of the non-surgically treated patients the clinical course was benign. In 26 of the surgically treated patients an improvement was noted at the short-term assessment both for spasticity and pain, but in most of them it was not maintained in the medium term. Therefore, an accurate selection of the patients to be treated surgically is strongly recommended, particularly when the natural history of the disease is considered. Decompression of the posterior fossa seems to give the best results, yet no curative surgical treatment has been devised to date.

Spinal cord and brain stem anomalies in scoliosis. MR screening of 26 cases

The spinal cord and brain were examined with magnetic resonance (MR) in 26 patients with idiopathic scoliosis to study the prevalence of spinal cord and brainstem anomalies. Two patients had small centrally located spinal cord syrinxes, one at C6-C8 and the other at T6-T8, without association with any brainstem or cerebellar deformity. The lowest position of the cerebellar tonsils was 0.5 cm below the foramen magnum, which was also seen in 2 other patients. Scoliosis associated with syringomyelia may be more common than previously thought, and may be wrongly classified as idiopathic. A neurogenic cause of scoliosis should always be considered, and at least in atypical cases be excluded by MR imaging of the spinal cord. MR should be mandatory before bracing or operative correction of scoliosis.

Clinico-morphological correlation in syringomyelia: a statistical study assisted by computer measurement of magnetic resonance images

A computer-assisted measurement of synrinxes was performed on MR images in a series of 26 patients with syringomyelia-Chiari complex. Syrinx data such as length, surface area, contour, and greater diameter were statistically correlated to each other and with the main clinical symptomatology of the patients. In general, a direct relationship between the various measurements of the syrinxes exists. Nevertheless, although a slight relationship could be established between the presence of muscular atrophy and a greater length and contour of the syrinxes, the present study suggests that the evaluation of syrinx dimensions cannot be brought into relation with the nature or distribution of clinical symptomatology. Because a reduction in the syrinx is generally the aim of surgery, this conclusion should be born in mind when a surgical treatment is offered to syringomyelic patients.

Hindbrain migration after decompression for hindbrain hernia: a quantitative assessment using MRI

Pre- and post-operative assessments are presented in 17 adult patients who have been treated with craniovertebral decompression for hindbrain herniation, 11 of whom had syringomyelia. Objective improvement in the size of the syrinx was seen in all 11 cases; contrary to expectation the hindbrain more frequently moved downwards than upwards after decompression of the tonsils and creation of an artificial cisterna magna. A method is reported for the quantitative assessment of hindbrain migration using magnetic resonance imaging (MRI). The degree of 'slump', further downward displacement of the hindbrain, was compared with the clinical outcome and the MRI appearances. Slump was more common than expected, although the severity was not usually great enough to produce symptoms. Slump was less marked where the artificial cisterna magna was generous (p less than 0.02). This quantitative method may be useful in assessing patients with unexplained post-operative symptoms and in comparing different surgical techniques.

Syringomyelia-Chiari complex: magnetic resonance imaging and clinical evaluation of surgical treatment

Thirty patients with syringomyelia-Chiari complex who underwent posterior fossa decompression or syringosubarachnoid shunting were studied clinically and by magnetic resonance (MR) imaging to assess the changes in the syrinx and in their clinical picture after surgery. When symptoms of posterior fossa compression were present, posterior fossa decompression was performed; however, when symptoms of posterior fossa compression were absent, the choice of posterior fossa decompression or syringosubarachnoid shunting depended, respectively, on whether the syrinx was narrow or wide on MR imaging. At least 1 year after surgery, subjective improvement or arrest of disease was recorded in 73% of the patients. The present study suggests that: 1) the symptoms attributed to spinal cord damage have no significant relationship to the size of the syrinx on MR images; 2) the surgical techniques employed in this series (posterior fossa decompression or syringosubarachnoid shunt) were equally useful in inducing syrinx collapse; and 3) when posterior fossa decompression is performed, plugging of the obex is not necessary for syrinx collapse.

MR imaging of syringobulbia with giant syrinx

Syringobulbia with a large syrinx was revealed by MR imaging. The syrinx extended from the medulla to vertebral level T10. We suspect that this giant syrinx may be produced by a congenital meningioma at C7, generating pulsatile flow in the original syrinx and causing a giant syrinx.