Transplantation of Human Neural Precursor Cells Reverses Syrinx Growth in a Rat Model of Post-Traumatic Syringomyelia

Posttraumatic syringomyelia (PTS) is a serious condition of progressive expansion of spinal cord cysts, affecting patients with spinal cord injury years after injury. To evaluate neural cell therapy to prevent cyst expansion and potentially replace lost neurons, we developed a rat model of PTS. We combined contusive trauma with subarachnoid injections of blood, causing tethering of the spinal cord to the surrounding vertebrae, resulting in chronically expanding cysts. The cysts were usually located rostral to the injury, extracanalicular, lined by astrocytes. T2*-weighted magnetic resonance imaging (MRI) showed hyperintense fluid-filled cysts but also hypointense signals from debris and iron-laden macrophages/microglia. Two types of human neural stem/progenitor cells-fetal neural precursor cells (hNPCs) and neuroepithelial-like stem cells (hNESCs) derived from induced pluripotent stem cells-were transplanted to PTS cysts. Cells transplanted into cysts 10 weeks after injury survived at least 10 weeks, migrated into the surrounding parenchyma, but did not differentiate during this period. The cysts were partially obliterated by the cells, and cyst walls often merged with thin layers of cells in between. Cyst volume measurements with MRI showed that the volumes continued to expand in sham-transplanted rats by 102%, while the cyst expansion was effectively prevented by hNPCs and hNESCs transplantation, reducing the cyst volumes by 18.8% and 46.8%, respectively. The volume reductions far exceeded the volume of the added human cells. Thus, in an animal model closely mimicking the clinical situation, we provide proof-of-principle that transplantation of human neural stem/progenitor cells can be used as treatment for PTS.

Scoliosis in patients with Chiari malformation type I

The literature about the association between Chiari malformations (CMs) and scoliosis has been growing over the last three decades; yet, no consensus on the optimal management approach in this patient population has been reached. Spinal anomalies such as isolated syrinxes, isolated CM, and CM with a syrinx are relatively common among patients with presumed idiopathic scoliosis (IS), a rule that also applies to scoliosis among CM patients as well. In CM patients, scoliosis presents with atypical features such as early onset, left apical or kyphotic curvature, and neurological deficits. While spinal X-rays are essential to confirm the diagnosis of scoliosis among CM patients, a magnetic resonance imaging (MRI) is also recommended in IS patients with atypical presentations. Hypotheses attempting to explain the occurrence of scoliosis in CM patients include cerebellar tonsillar compression of the cervicomedullary junction and uneven expansion of a syrinx in the horizontal plane of the spinal cord. Early detection of scoliosis on routine spinal examination and close follow-up on curve stability and progression are essential initial steps in the management of scoliosis, especially in patients with CM, who may require full spine MRI to screen for associated neuro-axial anomalies; bracing and spinal fusion may be subsequently pursued in high-risk patients.

Assessment and management of acute spinal cord injury: From point of injury to rehabilitation

CONTEXT

Spinal cord injury (SCI) is a devastating condition that can lead to significant neurological impairment and reduced quality of life. Despite advancements in our understanding of the pathophysiology and secondary injury mechanisms involved in SCI, there are currently very few effective treatments for this condition. The field, however, is rapidly changing as new treatments are developed and key discoveries are made.

METHODS

In this review, we outline the pathophysiology, management, and long-term rehabilitation of individuals with traumatic SCI. We also provide an in-depth overview of emerging therapies along the spectrum of the translational pipeline.

EVIDENCE SYNTHESIS

The concept of "time is spine" refers to the concept which emphasizes the importance of early transfer to specialized centers, early decompressive surgery, and early delivery of other treatments (e.g. blood pressure augmentation, methylprednisolone) to affect long-term outcomes. Another important evolution in management has been the recognition and prevention of the chronic complications of SCI including respiratory compromise, bladder dysfunction, Charcot joints, and pressure sores through directed interventions along with early integration of physical rehabilitation and mobilization. There have also been significant advances in neuroprotective and neuroregenerative strategies for SCI, many of which are actively in clinical trial including riluzole, Cethrin, stem cell transplantation, and the use of functional electrical stimulation.

CONCLUSION

Pharmacologic treatments, cell-based therapies, and other technology-driven interventions will likely play a combinatorial role in the evolving management of SCI as the field continues to evolve.

[Syringomyelias in paediatrics: a retrospective study of 25 cases]

INTRODUCTION

Syringomyelia is defined as a cavity containing cerebrospinal fluid inside the spinal cord.

AIM

To describe the clinical characteristics of a series of patients with syringomyelia, as well as its diagnosis and treatment.

PATIENTS AND METHODS

We conducted a retrospective descriptive study by reviewing the medical records at our centre.

RESULTS

We reviewed 25 patients diagnosed with syringomyelia. In five cases, the diagnosis was reached casually, and eight of them presented a previous severe pathology (tumour, bone or vascular). Two patients began with hydrocephalus and clinical signs and symptoms of intracranial hypertension and just two of them reported headaches as the only symptom. Four presented progressive scoliosis, two of them as the initial complaint, and required surgery with arthrodesis and the use of a corset, respectively. A notable feature was the earliness of the diagnosis. Most of them only presented a slight loss of strength, with normal somatosensory potentials and electromyogram. Check-ups were carried out with magnetic resonance. Eight patients required a decompressive craniectomy with posterior C1-C2 laminectomy, with drainage of the syringomyelic cavity in four cases. Nine of them required a bypass valve and a ventriculostomy also had to be performed in two of them.

CONCLUSIONS

The presence of syringomyelia is rare in paediatric patients, and is generally associated with malformations in the posterior fossa and a medical history of spinal dysrhaphism. Progressive scoliosis stands out as a possible isolated manifestation. A multidisciplinary approach with regular radiological check-ups and evaluation by paediatric neurology and neurosurgery services are mandatory for its follow-up.

Morvan syndrome: clinical and serological observations in 29 cases

OBJECTIVE

A study was undertaken to describe the clinical spectrum, voltage-gated potassium channel (VGKC) complex antibody specificities, and central nervous system localization of antibody binding in 29 patients diagnosed with Morvan syndrome (MoS).

METHODS

Clinical data were collected using questionnaires. Radioimmunoassay, cell-based assays, and mouse brain immunohistochemistry were used to characterize the serum antibodies.

RESULTS

Neuromyotonia (100%), neuropsychiatric features (insomnia 89.7%, confusion 65.5%, amnesia 55.6%, hallucinations 51.9%), dysautonomia (hyperhidrosis 86.2%, cardiovascular 48.3%), and neuropathic pain (62.1%) were the most common manifestations. A total of 93.1% of MoS patients were male. VGKC-complex antibodies were present in 23 of 29 (79%) MoS patients at referral; 24 of 27 available sera had CASPR2, LGI1, or both CASPR2 and LGI1 antibodies (3 also with contactin-2 antibodies). CASPR2 antibodies were generally higher titer than LGI1 antibodies. Tumors (41.4%), mainly thymomas, were associated with CASPR2 antibodies and a poor prognosis, whereas LGI1 antibodies were associated with serum hyponatremia. In brain tissue regions including the hypothalamus, raphe, and locus coeruleus, commercial antibodies to LGI1 bound to neuronal cell bodies including the antidiuretic hormone-secreting and orexin-secreting hypothalamic neurons, whereas CASPR2 commercial antibodies bound more often to the neuropil. MoS antibodies bound similarly, but there was evidence of additional antibodies in some sera that were not adsorbed by LGI1- or CASPR2-expressing cells and bound to mouse Caspr2(-/-) tissue.

INTERPRETATION

MoS is clinically distinct from other VGKC-complex antibody-associated conditions, and usually is associated with high-titer CASPR2 antibodies, often accompanied by lower-titer LGI1 antibodies. CASPR2 and LGI1 antibodies bind to multiple brain regions, which helps to explain the multifocal clinical features of this disease, but other antibodies are likely to play a role in some patients and need to be characterized in future studies.

Terminal ventriculostomy as an adjuvant treatment of complex syringomyelia: a case report and review of the literature

Complex syringomyelia is multifactorial, and treatment strategies are highly individualized. In refractory cases, sectioning of the filum terminale, also known as terminal ventriculostomy, has been described as a potential adjuvant treatment to alleviate syrinx progression. A 10-year-old boy with a history of arachnoiditis presented with complex syringomyelia, progressive lower extremity motor weakness, and spasticity. Previously, he had failed spinal cord detethering and direct syrinx shunting. Imaging studies demonstrated a holocord syrinx extending to the level of his conus medullaris and into the filum terminale. The patient underwent an uncomplicated lumbar laminectomy and transection of the filum terminale. Operative pathologic specimens demonstrated a dilated central canal within the filum. Postoperative imaging demonstrated significant reduction in the diameter of the syrinx. At follow-up, the patient's motor symptoms had improved. Terminal ventriculostomy may be a useful adjuvant in treating caudally placed syringes refractory to other treatments. This procedure carries low neurological risk and involves no hardware implantation. In select cases, terminal ventriculostomy may help preserve neurological function in the face of otherwise progressive syringomyelia.

A lumped-parameter model of the cerebrospinal system for investigating arterial-driven flow in posttraumatic syringomyelia

Fluid transport in syringomyelia has remained enigmatic ever since the disease was first identified some three centuries ago. However, accumulating evidence in the last decade from animal studies implicates arterial pulsations in syrinx formation. In particular, it has been suggested that a phase difference between the pressure pulse in the spinal subarachnoid space and the perivascular spaces, due to a pathologically disturbed cerebrospinal fluid (CSF) or blood supply, could result in a net influx of CSF into the spinal cord (SC). A lumped-parameter model is developed of the cerebrospinal system to investigate this conjecture. It is found that although this phase-lag mechanism may operate, it requires the SC to have an intrinsic storage capacity due to the collapsibility of the contained venous reservoir. This net flux is associated with a higher mean pressure in the SC than the SSS which is maintained in the periodic steady state. According to our simulations the mechanical perturbations of arachnoiditis exacerbate the phase-lag effect, which may be partially alleviated by the presence of a posttraumatic syrinx and more completely by a syringo-subarachnoid shunt.

[Anti-VGKC antibody-associated limbic encephalitis/Morvan syndrome]

Anti-voltage-gated potassium channel antibodies (anti-VGKC-Ab) cause hyperexcitability of the peripheral nerve and central nervous system. Peripheral nerve hyperexcitability is the chief manifestation of Issacs syndrome and cramp-fasciculation syndrome. Morvan syndrome is characterized by neuromyotonia with autonomic and CNS involvement. Manifestations involving the CNS without peripheral involvement are characteristic of limbic encephalitis and epilepsy. The clinical features of anti-VGKC-Ab-associated limbic encephalitis are subacute onset of episodic memory impairment, disorientation and agitation. Hyponatremia is also noted in most patients. Cortico-steroid therapy, plasma exchange and intravenous immunoglobulin are effective in treating to not only the clinical symptoms but also hyponatremia. Unlike other anti-VGKC-Ab-associated neurological disorders, paraneoplastic cases are rare. Thus, anti-VGKC-Ab-associated limbic encephalopathy is considered to be an autoimmune, non-paraneoplastic, potentially treatable encephalitis. Morvan syndrome is characterized by widespread neurological symptoms involving the peripheral nervous system (neuromyotonia), autonomic system (hyperhidrosis, severe constipation, urinary incontinence, and cardiac arrhythmia) and the CNS (severe insomnia, hallucinations, impairment of short-term memory and epilepsy). Many patients have an underlying tumor, for example thymoma, lung cancer, testicular cancer and lymphoma; this indicates the paraneoplastic nature of the disease. Needle electro-myography reveals myokimic discharge. In nerve conduction study, stimulus-induced repetitive descharges are frequently demonstrated in involved muscles. Plasma exchange is an effective treatment approach, and tumor resection also improves symptoms. Both VGKC-Ab-associated limbic encephalitis and Morvan syndrome can be successfully treated. Therefore, when these diseases are suspected, it's important to measure the anti-VGKC-Ab level.

A feline case of isolated fourth ventricle with syringomyelia suspected to be related with feline infectious peritonitis

A one-year-old female cat was unable to stand. Magnetic resonance imaging was performed, and an enlargement of the lateral, third, and fourth ventricles and syringomyelia were detected. The cat was diagnosed with an isolated fourth ventricle (IFV) with syringomyelia. The serum isoantibody test for the feline infectious peritonitis (FIP) virus was 1:3,200. After the cat died, a pathological examination revealed nonsuppurative encephalomyelitis. We suspected that the IFV, detected in the cat, was associated with FIP encephalomyelitis. To our knowledge, there has been no report on IFV in veterinary medicine.

Scoliosis associated with syringomyelia: analysis of MRI and curve progression

Little is known about the natural history of scoliosis found in patients with syringomyelia, including the factors affecting scoliosis curve progression and the effect of syrinx drainage treatment. Twenty patients having scoliosis with syringomyelia diagnosed by MRI were followed up for 6.6 (range 2.0-12.6) years on an average. Various factors potentially influencing curve pattern or progression in these patients were then retrospectively reviewed. The convex side of major curve of scoliosis tended to be on the same side as the syrinx and as the unilateral neurologic abnormality. No correlation was found between the location and the size of the syrinx and the location and size of the major curve of the scoliosis, or between the severity of neurologic deficit and the size of the major curve of the scoliosis. In patients under the age of ten at the time of diagnosis of scoliosis and with a flexible curve, decompression of the syrinx improved or stabilized scoliosis. In most patients over the age of ten, surgical treatment of the scoliosis was necessary because of the large initial size of the curve or progression of the curve even after syrinx drainage. Other factors including gender, location of the syrinx, type of the curve, and severity of neurologic deficits did not correlate with the progression of the curve. The results of this retrospective study suggest that early diagnosis and decompression of a syrinx in scoliosis patients especially under the age of ten is crucial and may decrease the curve size and limit scoliosis curve progression.

[Syringomyelia and Arnold-Chiari syndrome]

Many hypotheses concerning pathogenesis of syringomyelia were abandoned because of evidence found in more recent investigations. We should rank among them the "classical" theories of Gardner and Williams based on the assumption that syringomyelic cavities result from directing the fluid from the fourth ventricle to the central canal of the spine in the case of disturbances of circulation of the cerebrospinal fluid in the region of the cranio-spinal junction. The theory of intraspinal pulsation pressure of Greitz may explain the pathogenesis of syringomyelia in the case of obstacles to fluid flow from the cranial cavity to the spinal canal as in patients with Arnold-Chiari syndrome. The origin of Arnold-Chiari syndrome is connected with narrowness in the posterior fossa, particularly with narrowing of the arachnoid spaces. Improvement of clinical condition after surgical restoration of the fluid spaces within the posterior cranial cavity and improvement of cerebrospinal fluid flow in the region of the cranio-cervical junction are factors supporting this opinion.

Chiari malformations in patients with uncorrected sagittal synostosis

BACKGROUND

Single suture craniosynostoses were long considered a benign condition with little risk of complications. In many cases, parents may forego surgical correction because of the inherent risks of surgical intervention.

CASE DESCRIPTION

We report 2 cases of uncorrected sagittal synostosis associated with the development of Chiari malformations with syringomyelia later in life. To our knowledge, this is the first report of symptomatic Chiari malformations associated with uncorrected sagittal synostosis. We discuss mode of presentation and management in each case. We propose that these patients either have a pathophysiological predisposition to Chiari malformations based on the compensatory bone growth pattern in sagittal synostosis resulting in craniocephalic disproportion or that there may be an underlying genetic alteration accounting for the association of the 2 processes.

CONCLUSIONS

Further investigations are warranted to investigate whether the incidence of Chiari malformations is decreased in patients who have undergone early correction of an isolated sagittal synostosis. We conclude that patients with sagittal synostosis should be evaluated for Chiari malformations before being discharged permanently from a neurosurgical practice.

Acute presentation of hydromyelia in a child

The authors document a rapid development, within 3 weeks, of hydromyelia in a 12 year-old boy. The boy was admitted to a local hospital because of drowsiness and persistent severe neck pain. Neurological examination disclosed a lethargic boy with no neurological deficit other than Parinaud's sign. During his transfer to our department, he presented a cardio-respiratory arrest with coma and bilateral mydriasis. External ventricular drain and craniocervical decompression achieved excellent clinical and neuroradiological outcomes. The development of hydromyelia in this case is caused by obstruction to the natural cerebrospinal fluid pathway at the craniocervical junction and the cardio-respiratory arrest is provoked by a brain stem compression against the clivus and odontoid process. This report illustrates that hydromyelia may complicate acute obstructive hydrocephalus due to acquired Chiari malformation.

Myelopathy: a report of two cases

OBJECTIVE

To present diagnostic imaging findings of two cases of cervical myelopathy, with different etiologies, presenting to a chiropractic office.

CLINICAL FEATURES

The patient with acute transverse myelitis had neck and upper back pain and nonspecific headaches for 40 years. The patient with posttraumatic syringomyelia experienced intermittent left arm pain starting in the anterolateral shoulder and radiating down the arm into the third, fourth, and fifth digits. Neither of these patients presented with typical myelopathic symptoms.

INTERVENTION AND OUTCOME

Chiropractic spinal manipulative therapy using high-velocity low-amplitude thrusts and concomitant medical management were used for the patient with posttraumatic syringomyelia. The patient with acute transverse myelitis was not treated.

CONCLUSION

Practitioners should be aware of the etiology, pathophysiology, clinical features, laboratory, diagnostic imaging findings, and treatment options pertaining to patients with cervical myelopathy.

Syringomyelia: current concepts in pathogenesis, diagnosis, and treatment

Syringomyelia is a condition that results in fluid-containing cavities within the parenchyma of the spinal cord as a consequence of altered cerebrospinal fluid dynamics. This review discusses the history and the classification of the disorder, the current theories of pathogenesis, and the advanced imaging modalities used in the diagnosis. The intramedullary pulse pressure theory (a new pathophysiologic concept of syringomyelia) also is presented. In addition, the current understanding of the painful nature of this condition is discussed and the current trends in medical and surgical management are reviewed.

Primary spinal syringomyelia. Invited submission from the joint section meeting on disorders of the spine and peripheral nerves, March 2005

In the present review the author describes the different types of syringomyelia that originate from abnormalities at the level of the spinal cord rather than at the craniovertebral junction. These include posttraumatic and postinflammatory syringomyelia, as well as syringomyelia associated with arachnoid cysts and spinal cord tumors. The diagnosis and the principles of managing these lesions are discussed, notably resection of the entity restricting cerebrospinal fluid flow. Placement of a shunt into the syrinx cavity is reserved for patients in whom other procedures have failed or who are not candidates for other procedures.

Syringomyelia, neuropathic arthropathy and rheumatoid arthritis as diagnostic dilemmas in two different cases: confounding factor and true coexistence

Two patients with neuropathic arthropathy (NA) of hands and wrists due to cervical syringomyelia are described. Articular deformities resembling rheumatoid arthritis (RA) were present in both cases. RA was misdiagnosed in the first case, leading to incorrect treatment with iatrogenic consequences, and there was real coexistence of RA and NA in the second one. Physicians must be aware of this rare condition in the differential diagnosis of wrist and hand deformities.

Factors influencing the outcome in symptomatic Chiari I malformation

BACKGROUND

To study the clinico-radiological determinants of outcome in patients with Chiari I malformation (CIM).

MATERIALS AND METHODS

The disability assessment of 48 patients with C I M who underwent posterior decompression was done by modified Klekamp and Samii scoring system. The outcome was regarded as good when the patient was ambulant without any aid with an improvement in the disability score; and, poor when (a) there was postoperative deterioration or lack of improvement; (b) the patient was non-ambulant without aid, irrespective of the improvement in the clinical score; or, (c) there was a perioperative mortality. Patients with hydrocephalus; those who underwent syringo-subarachnoid or syringo-peritoneal shunt as the primary procedure; and, patients with atlanto-axial dislocation were excluded from the study. STATISTICAL METHODS USED: Categorical data were expressed in proportions and analyzed with Chi square test. Analysis of factors predicting clinical outcome at 6 months was done utilizing logistic regression analysis.

RESULTS

The outcome assessed at six months showed that 30 patients (62.5%) had good outcome while 18 patients (37.5%; including two perioperative mortalities) had a poor outcome.

CONCLUSIONS

Significant predictors of outcome in patients with CIM include the duration of symptoms (P value=0.006), respiratory distress (P value=0.001), and basilar invagination (P value=0.048). The effect of syringomyelia in predicting the clinical outcome could not be determined due to the differences in the number of patients in the groups with or without syringomyelia.

Post-traumatic syringomyelia: a review

More than a quarter of spinal cord injured patients develop syringes and many of these patients suffer progressive neurological deficits as a result of cyst enlargement. The mechanism of initial cyst formation and progressive enlargement are unknown, although arachnoiditis and persisting cord compression with disturbance of cerebrospinal fluid flow appear to be important aetiological factors. Current treatment options include correction of bony deformity, decompression of the spinal cord, division of adhesions, and shunting. Long-term improvement occurs in fewer than half of patients treated. Imaging evidence of a reduction in syrinx size following treatment does not guarantee symptomatic resolution or even prevention of further neurological loss. A better understanding of the causal mechanisms of syringomyelia is required to develop more effective therapy.

Transplant mediated repair of the central nervous system: an imminent solution?

PURPOSE OF REVIEW

This article reviews recent advances in the use of cell transplantation to promote recovery from traumatic injury of the CNS, focusing on axonal regeneration in the spinal cord.

RECENT FINDINGS

The significant recent findings reported are: (1) the increased expression of inhibitory chondroitin sulphate-proteoglycans in host tissue following Schwann cell transplantation, highlighting the effects the transplant may have on the ability of the host tissue to support regeneration; (2) the ability of embryonic and neural stem cells to promote recovery following transplantation into experimental models of spinal cord injury; (3) that delayed grafting for several weeks after transplantation does not diminish the graft effectiveness and may be advantageous; (4) the use of transplanted fibroblasts engineered to express neurotrophic genes in a conditionally regulated manner using tetracycline-inducible promoters; and (5) the initial reports on phase 1 clinical trials of foetal spinal cord grafts into patients with post-traumatic syringomyelia demonstrating their feasibility and safety.

SUMMARY

Recent advances largely involve experimental refinements of existing approaches and the emergent application of stem cell biology to overcome spinal cord injury. While most experimental studies concentrate on single or restricted combinations of approaches, the most effective clinical strategies will be multi-component. Their formulation will require the development of intermediate models for bridging the differences between experimental models in laboratory animals and naturally occurring traumatic injury in humans.

[Syringohydromyelia--coexistence or complication following removal of meningioma of forth ventricle]

Numerous theories have been presented to explain the pathogenesis of syringohydromyelia. Among these is Gardner's hydrodynamic theory with later modifications. Syrinx is usually located in cervical cord and is often associated with Arnold-Chiari, Dandy-Walker malformation or other anomalies of cranio-cervical region. Other theories suggest that syringohydromyelia may be secondary to arachnoiditis, neoplasms or spinal cord trauma. The distal location of the syrinx is very often associated with occult spinal dysraphic lesion. The authors present the case of 28 years old woman operated on meningioma of fourth ventricle. One and a half year later syrinx on Th11-Th12 and coexistent arachnoiditis were recognized. They stress diagnostic and therapeutic difficulties in this case and try to explain of etiology of syringohydromyelia.

Imaging in chronic spinal cord injury--indications and benefits

As most patients who have suffered spinal cord injury can now expect a normal life span, the late complications of these injuries are seen increasingly frequently. Regular surveillance of both the renal tract and the central nervous system (CNS) is important as the treatment of impending, potentially fatal complications can be implemented before damage has progressed too far. Renal tract complications are particularly dangerous as they are often clinically silent but regular surveillance to detect early deterioration in renal function, particularly from reversible causes such as reflux or obstruction can pre-empt problems. Follow-up protocols depend on the bladder management regime but most centres advocate regular ultrasound with less frequent isotope function studies. With the increasing ability to diagnose and treat the neurological complications, surveillance of the state of the spinal cord with MRI is also important and many centres now advocate checks every few years with sagittal midline T2W sections are sufficient unless changes are noted, when axial T1W sections can be added without significant examination time penalty. Imaging is critical in acute problems. In addition to suffering from the usual normal conditions, patients with spinal cord injury suffer others peculiar to, or particularly related to, the injury, which may be missed as their symptomatology is greatly altered by their paraplegic or quadriplegic status and they may often present as generally unwell but with no obvious cause. This review discusses the role of radiology in routine surveillance of the CNS and the renal tract as well as in assessing specific conditions such as deteriorating neurology or renal function, pain, spinal instability, pressure sores, ectopic ossification, muscular spasm, spinal instability, airway problems and elective operations on the renal tract.

Hydrocephalus and syringomyelia in a cat

A 3-month-old male Japanese cat with feline parvovirus infection, showing central and cervical nerve abnormalities, was diagnosed as hydrocephalus and syringomyelia by use of magnetic resonance imaging (MRI). The cat was maintained clinically by medical treatment even though he could not stand. The MRI scans obtained about 5 months later showed that the ventricles had increased in size and the cervical syrinx had extended into the thoracic spinal cord. Ventriculoperitoneal (VP) shunt was performed. One week after surgery, neurological conditions had improved. At the postoperative MR images, the ventricles had decreased in size and the syrinx in the cervical and thoracic spinal cord could no longer be seen. The cat was still alive and was able to walk well.

Spontaneous resolution of a syrinx

Syrinx are often related to trauma, tumours or abnormalities of the craniocervical junction. Only a few cases of spontaneous resolution have been reported in the literature. The authors present a case of spontaneous resolution of a cervical syrinx, and analyse the possible physiopathological mechanisms leading to resolution. Other similar cases reported in the literature were collected and analysed.

[Posttraumatic syringomyelia in 2 patients with thoracic spinal cord lesions]

Two patients, men aged 42 and 40 years, developed new neurological symptoms 3 months and 22 years, respectively, after a traumatic high thoracic spinal cord injury. The MRI scan showed a cavity in the central part of the spinal cord, on which the diagnosis of 'posttraumatic syringomyelia' could be based. In one of the patients a syringo-subarachnoidal shunt was created, the other was treated conservatively because of a severe concomitant thoracic kyphosis. Posttraumatic syringomyelia is a potentially life-threathening late complication of spinal cord injury and is characterized by development of new neurological symptoms after a variable time interval. The most typical symptom of non-traumatic syringomyelia, viz. diminution of vital sensitivity without loss of gnostic sensitivity, is not necessarily present in posttraumatic syringomyelia. Surgical treatment of posttraumatic syringomyelia is advocated if there is progressive neurological deterioration, and consists of drainage of the syrinx.

Features of spontaneous improvement in syringomyelia with low-situated cerebellar tonsils

We analysed four patients who showed spontaneous improvement among the 19 nonsurgically treated cases of syringomyelia with low-situated cerebellar tonsils who visited our outpatient clinic. MR images both before and after improvement were available for two of these patients; CT-myelography before improvement and MR images after improvement were used for two patients. Consequently, we were able to abstract several features from detailed and precise neurological and radiological evaluations of these patients. These features consisted of mild (rather than severe) disability, as well as three radiological features--a rounded shape of the lower edge of the cerebellar tonsils, a low tightness of the foramen magnum, an elevation of the tonsils during the course of the disease. Results of our radiological analyses were consistent with the theories proposed for the pathogenesis of syringomyelia in the light of the CSF flow around the foramen magnum. We propose that the features we have isolated are useful in determining treatment policies and prognoses of patients with syringomyelia, accompanied by low-situated cerebellar tonsils.

CT-guided percutaneous drainage of syringomyelia

PURPOSE

Our purpose is to describe CT-guided percutaneous drainage of syringomyelia as a possible contribution in patient management.

METHOD

CT-guided percutaneous drainage was performed on three patients with symptomatic syringomyelia. We determined the success of percutaneous decompression by subsequent CT and MRI. The effect of syringomyelia decompression in relation to the patient's symptoms was determined. This information was then used to help guide clinical management.

RESULTS

In Case 1, percutaneous drainage of a large syrinx in a C5 quadriplegic patient with increasing lower extremity spasticity demonstrated significant decompression by imaging but did not result in clinical improvement. A surgical procedure to decompress the syrinx was not performed on the basis of this information. In Case 2, percutaneous drainage of a large syrinx in a quadriplegic patient with increasing upper extremity numbness and weakness demonstrated significant decompression by imaging and resulted in sustained clinical improvement, temporarily obviating the need for surgery. In Case 3, percutaneous drainage of the rostral aspect of a septated syrinx cavity in a patient with a Chiari I malformation and a syringoperitoneal shunt in place resulted in decompression by imaging but failed to relieve the patient's newly developed symptoms. An additional shunt was therefore not placed. In no case did the patient experience periprocedural complications or worsening of symptoms.

CONCLUSION

CT-guided percutaneous drainage of syringomyelia is a safe and successful technique. It can be used diagnostically to identify patients that may or may not benefit from surgical syrinx decompression and in some cases may provide a temporary therapeutic alternative to surgery.

The acquired Chiari malformation and syringomyelia following spinal CSF drainage: a study of incidence and management

Firstly, 14 patients are described who developed either an acquired Chiari malformation (ACM) alone (7 cases) or ACM and syringomyelia (7 cases) after lumbar subarachnoid space (SAS) shunting or in one case, epidural anaesthesia with SAS penetration. Four groups are considered: 3 cases with craniofacial dysostosis and communicating hydrocephalus (CH), 4 cases with CH alone, 3 cases with pseudotumour cerebri (PTC) and a miscellaneous group (4 cases). Initial treatment was varied: resiting the shunt to ventricle or cisterna magna [6], adding an H-V valve [1], syrinx shunting [4] and posterior fossa decompression [3]. Further treatment was required in 6 cases. Secondly, incidence was examined in 87 patients with PTC initially treated either by lumbar SAS shunting [70] or cisterna magna shunting [17]. In the first sub-group, 11 cases (15.7 per cent) developed an ACM, 3 symptomatic (as above) and eight asymptomatic with 1 case also having syringomyelia whereas 1 case occurred in the second group with a questionanably symptomatic ACM. While accurate for symptomatic lesions, these figures are tentative with respect to asymptomatic lesions due to inadequate pre-treatment radiology and detailed MR follow-up. The main conclusions are, first, that the incidence of symptomatic ACM and/or syringomyelia is not high enough to warrant abandoning SAS shunting; second that asymptomatic lesions need not necessarily be treated and third, that when treatment is required, shunt resiting is the first choice.

Features of spontaneous improvement in syringomyelia with low-situated cerebellar tonsils

We analysed six patients who showed spontaneous improvement among the 19 nonsurgically treated cases of syringomyelia with low-situated cerebellar tonsils who visited our outpatient clinic. MR images both before and after improvement were available for two of these patients; CT-myelography before improvement and MR images after improvement were used for two patients; and in the remaining two patients, MR images after improvement only were used. Consequently, we were able to abstract several features from detailed and precise neurological and radiological evaluations of these patients. These features consisted of mild (rather than severe) disability, as well as four radiological features--a rounded shape of the lower edge of the cerebellar tonsils, a low tightness of the foramen magnum, an elevation of the tonsils during the course of the disease. Results of our radiological analyses were consistent with the theories proposed for the pathogenesis of syringomyelia in the light of the CSF flow around the foramen magnum. We propose that the features we have isolated are useful in determining treatment policies and prognoses of patients with syringomyelia accompanied by low-situated cerebellar tonsils.

Syringomyelia and scoliosis in children

We reviewed 28 patients < 18 years of age with scoliosis and syringomyelia. Children with scoliosis and syringomyelia had an equal incidence of left- and right-sided curves with a normal sagittal alignment. Most were first seen at Risser 0 with significant curves, and curve progression occurred in half of the patients. Bracing was not effective in preventing curve progression. Neurologic signs, present in most children, stabilized after syrinx drainage. Neither the sex or age of the child, nor the type of curve, nor the drainage of the syrinx was predictive of curve progression.

Von Hippel-Lindau disease with multiple spinal cord hemangioblastomas, syringomyelia and pheochromocytoma

A 31-year-old blind man presented with numbness and weakness in the left hand, and elevated blood pressure. Multiple hemangioblastomas in the spinal cord associated with syringomyelia were well demonstrated by gadolinium-enhanced magnetic resonance imaging (MRI). He also had pheochromocytoma in the right adrenal gland, which was disclosed by abdominal computed tomography, MRI and 131I-metaiodobenzylguanidine scintigraphy. MRI screening should be considered for patients with von Hippel-Lindau gene to detect the multiple lesions in this disease.

[Syringomyelia as a rare cause of respiratory insufficiency requiring ventilation]

For 17 years a now 45-year-old man had suffered from progressively more severe flaccid paresis of the arms and thoracic muscles, spastic paralysis of the legs and kyphoscoliosis. Artificial ventilation was required when he contracted pneumonia. Although it was being treated with antibiotics, frequent bronchoalveolar lavage had to be done because of repeated atelectases. After 6 weeks clonuses developed in the legs, predominantly on the right, stretch synergisms and opisthotonos. The pupils were small with sluggish reaction to light, and there was a positive "doll's head" phenomenon. The level of consciousness alternated between somnolence and sleepiness. Magnetic resonance imaging demonstrated cavities in cervical and thoracic spinal cord, supporting the diagnosis of an abnormal cerebrospinal circulation due to gliosis in syringomyelia. To secure cerebrospinal fluid drainage, the cerebellar tonsils were resected, together with a duraplasty and partial resection of the atlas. Following this he became fully conscious and the spastic state improved. During the following 8 weeks it became possible gradually to wean him from the artificial ventilation and achieve satisfactory mobilization so that he could be discharged to domiciliary care.

Post-traumatic syringomyelia: a review of the literature

The need for increased awareness and a high index of suspicion for post traumatic syringomyelia is emphasised. Early clinical diagnosis confirmed by MRI and early treatment can avert or minimise the potentially devastating effects of post traumatic syringomyelia. The regular and frequent follow up of the patient on a yearly or alternate year basis to monitor the patient with spinal injury for this complication, as well as other complications, is the best way to ensure that post traumatic syringomyelia is diagnosed and managed early in order to avoid further disability.

Chiari malformations, syringomyelia, and intramedullary spinal cord tumors

Optimal management of congenital and acquired spinal cord lesions, such as Chiari malformations, syringomyelia, and intramedullary spinal cord tumors, depends on an understanding of the pathogenesis and natural history of these lesions. Magnetic resonance imaging and detailed physiologic investigations are shedding new light on these difficult-to-diagnose entities, and new surgical techniques are aiding in their management.

Percutaneous drainage and serial magnetic resonance imaging in the diagnosis of symptomatic posttraumatic syringomyelia: case report and review of the literature

A patient with high cervical tetraplegia with new-onset headaches and posttraumatic syringomyelia is presented. Percutaneous drainage of the syrinx resulted in a resolution of the headaches and collapse of the syrinx on follow-up magnetic resonance imaging (MRI). The return of the symptoms correlated with the re-expansion of the syrinx on MRI. The patient underwent syringopleural shunting with persistent resolution of the symptoms and collapse of the syrinx on MRI. The value of percutaneous drainage and serial MRI to determine the clinical significance of posttraumatic syringomyelia is discussed.

Neurological improvement following respiratory support in syringomyelia: case report

Respiratory failure in syringomyelia has rarely been reported. We report a patient with syringomyelia who showed some neurological improvement after intermittent respiratory support with negative and positive pressure ventilation.