Clinicopathological correlations in syringomyelia using axial magnetic resonance imaging

Ependymal cilia decline and AQP4 upregulation in young adult rats with syringomyelia

BACKGROUND

Syringomyelia was a rare condition characterized by the formation of fluid-filled cysts (syrinx) within the spinal cord, resulting in sensory and motor dysfunction. Currently, there was no satisfactory treatment for syringomyelia. Ependymal cells were integral to water transport and may represent a promising therapeutic target.

METHODS

Induction of syringomyelia occurred in 8-week old female rats followed by histological analyses at 3-, 7-, 14-, 30-, 60-, 180-, and 365-days later. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed to visualize cilia on rat central canal membrane cells at 30-day post-induction. Syringomyelia was induced via compression at T12-T13 using a sterile cotton ball. Each rat underwent MRI scanning one day before induction and one day prior to sacrifice. In vivo magnetic resonance imaging (MRI) was utilized to measure syrinx enlargement in eight-week-old syringomyelia rats. Histological Analysis and immunofluorescence staining were performed for changes of cilia, neurons, expression of AQP4 and infiltration of immune cells into spinal tissue.

RESULTS

In the current study, the cell junctions between ependymal cells of syringomyelia rats were absent, and the cilia on ependymal cells were reduced significantly on day 30 post syringomyelia. The number of ependymal cells kept increasing lasting for 1-2 months and begin to decrease. Edema and vacuolation in the spinal cord tissue are significant in syringomyelia rats. Furthermore, AQP4 expression was elevated in astrocytes of syringomyelia rats, and IBA1+ immune cells infiltrated spinal tissue. Furthermore, neuronal necrosis began in the acute stage of syringomyelia, and reached its peak one month later. Pathological changes in axonal rupture at anterior commissure (connection of the left and right white matter) could be observed in syringomyelia spinal tissue.

CONCLUSIONS

These findings underscored the significance of cilia on ependymal cells and the evolving microenvironment post-syringomyelia, providing valuable insights for clinical treatment strategies for this condition.

Spinal cord tethering and syringomyelia after trauma: impact of age and surgical outcome

Posttraumatic spinal cord tethering and syringomyelia frequently lead to progressive neurological loss. Although several studies demonstrated favourable outcome following spinal cord detethering with/without shunting, additional research is required as no clear consensus exists over the ideal treatment strategy and knowledge about prognostic demographic determinants is currently limited. In this investigation, we retrospectively investigated 67 patients (56 men, 11 women) who were surgically treated and followed for symptomatic spinal cord tethering and syringomyelia from 2012 to 2022 at our center. Age (B-coefficient 0.396) and severity of trauma to the spinal cord (B-coefficient - 0.462) have been identified as independent predictors for the rate of development of symptomatic spinal cord tethering and syringomyelia (p < 0.001). Following untethering surgery including expansion duraplasty with/without shunting, 65.9% of patients demonstrated an improvement of neurological loss (p < 0.001) whereas 50.0% of patients displayed amelioration of spasticity and/or neuropathic pain (p < 0.001). Conclusively, active screening for symptomatic spinal cord tethering and syringomyelia, particularly in younger patients with severe spinal trauma, is crucial as surgical untethering with/without shunting is able to achieve favourable clinical outcomes. This knowledge may enable clinicians to tailor treatment strategies in spinal cord injury patients suffering from progressive neurological loss towards a more optimal and personalized patient care.

Knowledge mapping of syringomyelia from 2003 to 2022: A bibliometric analysis

BACKGROUND

Syringomyelia is a chronic, progressive disease of the spinal cord. Syringomyelia is an etiologically diverse affliction caused by disturbance of normal cerebrospinal fluid flow dynamics. Lesions are characterized by the formation of tubular cavities in the gray matter of the spinal cord and gliosis; however, the etiology is unknown and treatment methods differ. Many existing studies have focused on the relationship between other diseases and syringomyelia. There is a lack of comprehensive and objective reports on the research status of syringomyelia. Therefore, this study aimed to conduct a bibliometric analysis to quantify studies on Syringomyelia and trending issues in the last 20 years.

METHODS

Articles were acquired from the Web of Science Core Collection database. We used the Library Metrology online analysis platform, BICOMB, gCLUTO, CiteSpace bibliometrics tools for analysis, VOSviewer 1.6.16 (Nees Jan van Eck and Ludo Waltman, 2010), and Microsoft Excel 2019 to perform bibliometric analysis and visualization. Individual impact and collaborative information were quantified by analyzing annual publications, journals, co-cited journals, countries/regions, institutions, authors, and co-cited authors. We then identified the trending research areas of syringomyelia by analyzing the co-occurrence of keywords and co-cited references.

RESULTS

From January 2003 to August 2022, 9,556 authors from 66 countries published a total of 1,902 research articles on syringomyelia in 518 academic journals. Most publications come from the United States, China, the United Kingdom, and Japan, with the United States dominating. Nanjing University and the University of Washington are the most active institutions, Dr. Claire Rusbridge has published the most papers, and Miholat has the most co-citations. The Journal of Neurosurgery has the highest number of co-cited articles, which are mainly in the fields of neurology, surgery, and biology. High-frequency keywords included syringomyelia, Chiari-I malformation, children, surgical treatment, and spinal cord.

CONCLUSIONS

The number of articles on syringomyelia has increased steadily over the past two decades. At present, research on syringomyelia is mainly focused on the age of onset, potential therapeutic interventions, surgical treatment, avoidance of recurrence, and delay of pain. The use of surgical treatment of the disease and the mechanism of further treatment are the current hot research topics. The correlation between trauma and congenital factors, translational application, the effect of surgical treatment, postoperative recurrence, and complications are further hot research areas. These may provide ideas for further research into a radical cure for syringomyelia.

Two differential cavities in syringomyelia of pediatric Chiari I malformation presenting with unilateral foot drop

INTRODUCTION

Patients with Chiari I malformation (CM1) may have chronic symptoms of syringomyelia, including numbness and weakness of the upper limbs, typically during young adulthood. Acute or subacute presentation of unilateral foot drop has been rarely reported as a first symptom of CM1-associated syringomyelia exclusively in childhood or adolescence. Why these patients do not show any symptoms of the upper limbs although holocord syringomyelia is always observed on magnetic resonance imaging (MRI) is unclear.

CASE PRESENTATION

A four-year-old girl presented rapidly with isolated left foot drop. Conventional MRI revealed holocord syringomyelia associated with CM1. Three-dimensional constructive interference in steady state (3D-CISS) imaging further demonstrated that the syringomyelia was comprised of two differential cavities that communicated with each other via a small pore: a centrally positioned upper cavity and a left-deviated lower one. Surgical decompression of the foramen magnum resolved the symptom with radiological improvement of the two cavities.

CONCLUSION

In contrast to a centrally enlarged syrinx that is often asymptomatic, a paracentrally extended syrinx usually produces segmental signs related to its levels. Thus, the left foot drop in this case would have been due to the ipsilaterally deviated lower cavity that was distinguished from the central upper cavity by 3D-CISS imaging. Further reports using this imaging technique are needed to verify the hypothetic pathology.

The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis)

BACKGROUND & IMPORTANCE

This patient and public-involved systematic review originally focused on arachnoiditis, a supposedly rare "iatrogenic chronic meningitis" causing permanent neurologic damage and intractable pain. We sought to prove disease existence, causation, symptoms, and inform future directions. After 63 terms for the same pathology were found, the study was renamed Diseases of the Leptomeninges (DLMs). We present results that nullify traditional clinical thinking about DLMs, answer study questions, and create a unified path forward.

METHODS

The prospective PRISMA protocol is published at Arcsology.org. We used four platforms, 10 sources, extraction software, and critical review with ≥2 researchers at each phase. All human sources to 12/6/2020 were eligible for qualitative synthesis utilizing R. Weekly updates since cutoff strengthen conclusions.

RESULTS

Included were 887/14286 sources containing 12721 DLMs patients. Pathology involves the subarachnoid space (SAS) and pia. DLMs occurred in all countries as a contributor to the top 10 causes of disability-adjusted life years lost, with communicable diseases (CDs) predominating. In the USA, the ratio of CDs to iatrogenic causes is 2.4:1, contradicting arachnoiditis literature. Spinal fusion surgery comprised 54.7% of the iatrogenic category, with rhBMP-2 resulting in 2.4x more DLMs than no use (p<0.0001). Spinal injections and neuraxial anesthesia procedures cause 1.1%, and 0.2% permanent DLMs, respectively. Syringomyelia, hydrocephalus, and arachnoid cysts are complications caused by blocked CSF flow. CNS neuron death occurs due to insufficient arterial supply from compromised vasculature and nerves traversing the SAS. Contrast MRI is currently the diagnostic test of choice. Lack of radiologist recognition is problematic.

DISCUSSION & CONCLUSION

DLMs are common. The LM clinically functions as an organ with critical CNS-sustaining roles involving the SAS-pia structure, enclosed cells, lymphatics, and biologic pathways. Cases involve all specialties. Causes are numerous, symptoms predictable, and outcomes dependent on time to treatment and extent of residual SAS damage. An international disease classification and possible treatment trials are proposed.

Diagnosis and treatment of Chiari malformation type 1 in children: the International Consensus Document

BACKGROUND

Chiari malformation type 1 (CM1) is a rare condition where agreed classification and treatment are still missing. The goal of this study is to achieve a consensus on the diagnosis and treatment of CM1 in children.

METHODS

A multidisciplinary panel formulated 57 provisional statements based on a review of the literature. Thirty-four international experts (IE) participated in a Delphi study by independently rating each statement on a 4-point Likert scale ("strongly disagree," "disagree," "agree," "strongly agree"). Statements that were endorsed ("agree" or "strongly agree") by < 75% of raters were re-formulated, or new statements were added, and another Delphi round followed (up to a maximum of three).

RESULTS

Thirty-five IE were contacted and 34 agreed to participate. A consensus was reached on 30/57 statements (52.6%) after round 1. Three statements were added, and one removed. After round 2, agreement was reached on 56/59 statements (94.9%). Finally, after round 3, which took place during the 2019 Chiari Consensus Conference (Milan, Italy), agreement was reached on 58/59 statements (98.3%) about four main sections (Definition and Classification, Planning, Surgery, Isolated Syringomyelia). Only one statement did not gain a consensus, which is the "definition of radiological failure 24 month post-surgery."

CONCLUSIONS

The consensus document consists of 58 statements (24 on diagnosis, 34 on treatment), serving clinicians and researchers following children with CM1. There is a clear need for establishing an international network and registry and to promote collaborative studies to increase the evidence base and optimize the long-term care of this patient population.

Development of pre-syrinx state and syringomyelia following a minor injury: a case report

Background

A generally accepted rule is that posttraumatic syringomyelia (PTS) results from spinal cord injury (SCI).

Case presentation

Here, we report the development of syringomyelia without SCI in a 54-year-old Caucasian man following a mild motor vehicle accident. The computed tomography on admission excluded an injury of the spine. Because of neck and back pain, magnetic resonance imaging was performed on day 3 post-injury and demonstrated minimal changes from a ligamentous strain at the cervicothoracic transition. Any traumatic affection of the bone, vertebral discs, intraspinal compartment, or spinal cord were excluded. Some limb weakness and neurogenic bladder dysfunction started manifesting within the following weeks. Repeated MRIs following the accident demonstrated arachnoid adhesions at the C1–2 level and spinal cord edema equivalent to a pre-syrinx state at 12 months and syrinx formation at 24 months. Because of further deterioration, decompression was performed at 36 months.

Conclusions

We conclude that even after a minor trauma PTS can occur and that medullary edema (pre-syrinx state) may precede syrinx formation.

Treatment of posttraumatic syringomyelia: evidence from a systematic review

Background

Following spinal cord injury (SCI), the routine use of magnetic resonance imaging (MRI) resulted in an incremental diagnosis of posttraumatic syringomyelia (PTS). However, facing four decades of preferred surgical treatment of PTS, no clear consensus on the recommended treatment exists. We review the literature on PTS regarding therapeutic strategies, outcomes, and complications.

Methods

We performed a systematic bibliographic search on (“spinal cord injuries” [Mesh] AND “syringomyelia” [Mesh]). English language literature published between 1980 and 2020 was gathered, and case reports and articles examining syrinx due to other causes were excluded. The type of study, interval injury to symptoms, severity and level of injury, therapeutic procedure, duration of follow-up, complications, and outcome were recorded.

Results

Forty-three observational studies including 1803 individuals met the eligibility criteria. The time interval from SCI to the diagnosis of PTS varied between 42 and 264 months. Eighty-nine percent of patients were treated surgically (n = 1605) with a complication rate of 26%. Symptoms improved in 43% of patients postoperatively and in 2% treated conservatively. Stable disease was documented in 50% of patients postoperatively and in 88% treated conservatively. The percentage of deterioration was similar (surgery 16%, 0.8% dead; conservative 10%). Detailed analysis of surgical outcome with regard to symptoms revealed that pain, motor, and sensory function could be improved in 43 to 55% of patients while motor function deteriorated in around 25%. The preferred methods of surgery were arachnoid lysis (48%) and syrinx drainage (31%).

Conclusion

Even diagnosing PTS early in its evolution with MRI, to date, no satisfactory standard treatment exists, and the present literature review shows similar outcomes, regardless of the treatment modality. Therefore, PTS remains a neurosurgical challenge. Additional research is required using appropriate study designs for improving treatment options.

Thoracic ossification of ligamentum flavum manifesting holocord syringomyelia: case report

It has been reported that syringomyelia is rarely associated with degenerative spinal disorders, but the case of holocord syringomyelia is never reported. We here present a case of a 59-year-old woman with right shoulder pain, dysesthesia of the right hand, and gait disturbance. Radiographically, examinations of the spine demonstrated holocord syringomyelia with ossification of ligamentum flavum at T2/3 level. Holocord syringomyelia was reduced remarkably after posterior decompression at the T2/3 level, and her symptoms also improved. We speculated that holocord syringomyelia might have developed due to craniospinal pressure dissociation caused by focal compression of dural sac from extradural degenerative change.

A points-based algorithm for prognosticating clinical outcome of Chiari malformation Type I with syringomyelia: results from a predictive model analysis of 82 surgically managed adult patients

OBJECTIVE Although various predictors of postoperative outcome have been previously identified in patients with Chiari malformation Type I (CMI) with syringomyelia, there is no known algorithm for predicting a multifactorial outcome measure in this widely studied disorder. Using one of the largest preoperative variable arrays used so far in CMI research, the authors attempted to generate a formula for predicting postoperative outcome. METHODS Data from the clinical records of 82 symptomatic adult patients with CMI and altered hindbrain CSF flow who were managed with foramen magnum decompression, C-1 laminectomy, and duraplasty over an 8-year period were collected and analyzed. Various preoperative clinical and radiological variables in the 57 patients who formed the study cohort were assessed in a bivariate analysis to determine their ability to predict clinical outcome (as measured on the Chicago Chiari Outcome Scale [CCOS]) and the resolution of syrinx at the last follow-up. The variables that were significant in the bivariate analysis were further analyzed in a multiple linear regression analysis. Different regression models were tested, and the model with the best prediction of CCOS was identified and internally validated in a subcohort of 25 patients. RESULTS There was no correlation between CCOS score and syrinx resolution (p = 0.24) at a mean ± SD follow-up of 40.29 ± 10.36 months. Multiple linear regression analysis revealed that the presence of gait instability, obex position, and the M-line-fourth ventricle vertex (FVV) distance correlated with CCOS score, while the presence of motor deficits was associated with poor syrinx resolution (p ≤ 0.05). The algorithm generated from the regression model demonstrated good diagnostic accuracy (area under curve 0.81), with a score of more than 128 points demonstrating 100% specificity for clinical improvement (CCOS score of 11 or greater). The model had excellent reliability (κ = 0.85) and was validated with fair accuracy in the validation cohort (area under the curve 0.75). CONCLUSIONS The presence of gait imbalance and motor deficits independently predict worse clinical and radiological outcomes, respectively, after decompressive surgery for CMI with altered hindbrain CSF flow. Caudal displacement of the obex and a shorter M-line-FVV distance correlated with good CCOS scores, indicating that patients with a greater degree of hindbrain pathology respond better to surgery. The proposed points-based algorithm has good predictive value for postoperative multifactorial outcome in these patients.

Stereological and Morphometric Analysis of MRI Chiari Malformation Type-1

Objective

In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements.

Methods

A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies were evaluated. Supratentorial, infratentorial, and total intracranial volumes were measured using Cavalieri method. Various cranial distances and angles were used to evaluate the platybasia and posterior cranial fossa (PCF) development.

Results

Tonsillar herniation length was measured 9.09±3.39 mm below foramen magnum in CM group. Tonsillar herniation/concurrent syringomyelia, concavity/defect of clivus, herniation of bulbus and fourth ventricle, basilar invagination and craniovertebral junction abnormality rates were 30.3, 27, 18, 2, 3, and 3 percent, respectively. Absence of cisterna magna was encountered in 87.9% of the patients. Total, IT and ST volumes and distance between Chamberlain line and tip of dens axis, Klaus index, clivus length, distance between internal occipital protuberance and opisthion were significantly decreased in patient group. Also in patient group, it was found that Welcher basal angle/Boogard angle increased and tentorial slope angle decreased.

Conclusion

Mean cranial volume and length-angle measurement values significantly decreased and there was a congenital abnormality association in nearly 81.5 percent of the CM cases. As a result, it was concluded that CM ethiology can be attributed to multifactorial causes. Moreover, congenital defects can also give rise to this condition.

Volume change theory for syringomyelia: A new perspective

Background:

The etiopathogenesis of syringomyelia is still an enigma. The authors present a novel theory based on fluid dynamics at the craniovertebral (CV) junction to explain the genesis of syringomyelia (SM). The changes in volume of spinal canal, spinal cord, central canal and spinal subarachnoid space (SSS) in relation to the posterior fossa have been analysed, specifically during postural movements of flexion and extension. The effect of fluctuations in volume of spinal canal and its contents associated with cerebrospinal fluid (CSF) flow dynamics at the CV junction have been postulated to cause the origin and propagation of the syringomyelia. The relevant literature on the subject has been reviewed and the author's theory has been discussed.

Conclusion:

Volume of spinal canal in flexion is always greater than that in extension. Flexion of spine causes narrowing of the ventral subarachnoid space (SAS) and widening of dorsal SAS while extension causes reverse changes leading to fluid movement in dorsal spinal SAS in flexion and ventral spinal SAS in extension. Cervical and lumbar spinal region with maximum bulk hence maximum area and volume undergo maximum deformation during postural changes. SSS CSF is the difference between the volume of spinal canal and spinal cord, varies in flexion and extension which is compensated by changes in posterior fossa (CSF) volume in normal circumstances. Blocked SAS at foramen magnum donot permit spinal SAS CSF exchange which during postural changes is compensated by cavitatory/cystic (syrinx) change at locations in cervical and lumbar spine with propensity for maximum deformation. Augmentation of posterior fossa volume by decompression helps by normalization of this CSF exchange dynamics but immobilizing the spinal movement theoretically will cease any dynamic volume changes thereby minimizing the destructive influence of the fluid exchange on the cord. Thus, this theory strengthens the rational of treating patients by either methodology.

Syringomyelia in an older patient

We describe the case of an 80-year-old man who presented with lower limb upper motor neurone weakness and spinothalamic tract sensory deficit secondary to previously undiagnosed syringomyelia. The case highlights the need for methodical history, examination and investigation in elderly patients to achieve diagnostic accuracy.

Factors contributing to improvement of syringomyelia after foramen magnum decompression for Chiari type I malformation

BACKGROUND

Although various surgical approaches have been proposed for treating syringomyelia associated with Chiari type I malformation, a standard method has yet to be established. we prospectively investigated the results of our surgical method: foramen magnum decompression combined with C1 laminectomy and excision of the outer layer of the dura mater.

METHODS

Twenty patients underwent surgery between 2000 and 2010 at our hospital. After surgery, the size of the syrinx decreased in 11 patients (decreased group) but remained unchanged in nine patients (unchanged group). The following parameters were compared: age at the time of surgery, duration of morbidity, improvement of preoperative symptoms, morphological type and length of the syrinx, presence or absence of scoliosis, cervical alignment, basal and clivo-axial angles, and postoperative subarachnoid space at the foramen magnum level.

RESULTS

Preoperative symptoms improved in all patients in the decreased group but in only one patient in the unchanged group. The average duration of morbidity was significantly shorter in the decreased group. Morphological examination revealed that the size of all central-type syrinxes decreased after surgery, whereas in all cases of deviated-type syrinx, size was unchanged. The average length of preoperative syrinx was significantly shorter in the decreased group. The postoperative subarachnoid space at the foramen magnum was enlarged in the entire decreased group, whereas residual narrowing of the space was observed in 44 % of patients in the unchanged group. No significant intergroup differences were observed in the other factors.

CONCLUSIONS

In patients with syringomyelia, a longer and deviated type of syrinx, a longer duration of morbidity, and postoperative residual narrowing of the subarachnoid space are associated with a poor prognosis after the surgical procedure. The pathogenesis of syringomyelia is inconsistent, and the choice of surgical technique for each pathological condition is important.

Communicating syringomyelia associated with ventriculoperitoneal shunt malfunction verified with a cerebrospinal fluid dynamic study: case report

HISTORY

A 20-year-old male presented with neck pain and motor impairment of the upper extremities because of recurrent syringomyelia caused by ventriculoperitoneal shunt malfunction.

EXAMINATION AND OPERATION

A computed tomography scan after shuntgraphy demonstrated opacity in the intracranial ventricular system and cervical syrinx with contrast medium, which indicated communication between the fourth ventricle and syrinx. His symptoms resolved immediately after peritoneal catheter replacement, and magnetic resonance images obtained 1 week after surgery showed the complete resolution of hydrocephalus and syringomyelia.

CONCLUSION

Syringomyelia associated with ventriculoparitoneal shunt malfunction is a well-known complication in myelodysplastic patients; however, this is the first case in which communicating syringomyelia was verified with a cerebrospinal fluid dynamic study. As the present case involved communicating syringomyelia, it could only be resolved by shunt revision surgery.

Syringomyelia and tethered cord in children

INTRODUCTION

The presence of syringomyelia varies in patients with different forms of dysraphism; from 21 % to 67 %. Only around 60 % of patients with syringomyelia is likely to experience symptoms related to it.

PATHOPHYSIOLOGY

Many theories have been outlined for the creation of syringomyelia. The one most applicable to tethered cord dictates that tensile radial stress may create a syrinx in a previously normal cord tissue and transiently lower pressure may draw in interstitial fluid, causing the syrinx to enlarge if fluid exit is inhibited. In addition, arachnoiditis increases flow resistance in the spinal subarachnoid space, altering temporal CSF pulse pressure dynamics, which promotes entry of CSF in to the spinal cord.

CLINICAL PRESENTATION

There is a significant overlap between the symptoms that are due to tethered cord and syringomyelia, both in newly presenting patients with coexisting syringomyelia, and in previously treated patients who during follow-up present recurrent symptoms and a new syringomyelia cavity.

TREATMENT

The treatment of patients with tethered cord and syringomyelia is directed towards untethering the cord from its most caudal region upwards and restoring spinal anatomy with reestablishment of unobstructed CSF flow in the subarachnoid space. Only if complete untethering has been ensured and syringomyelia deteriorates, then surgical treatment can be directed against the syrinx. In patients with spinal dysraphism and coexisting hydrocephalus, radiological presentation of new syringomyelia or deterioration of previously known syringomyelia may signify shunt obstruction "until proven otherwise".

CONCLUSION

In most occasions, satisfactory cord untethering addresses the development of syringomyelia.

A potential role for substance P and interleukin-6 in the cerebrospinal fluid of Cavalier King Charles Spaniels with neuropathic pain

BACKGROUND

Neuropathic pain can be a clinical sign in Cavalier King Charles Spaniels (CKCS) with syringomyelia. The pathophysiology of this pain is not fully understood.

HYPOTHESIS

Neuropathic pain in CKCS is a result of a neuroinflammatory process.

ANIMALS

Twenty-six client-owned dogs: 15 dogs with clinical signs of cervical hyperesthesia (group 1), and 11 dogs without of clinical signs (group 2).

METHODS

Dogs were examined by magnetic resonance imaging (MRI). Interleukin-6, tumor necrosis factor alpha, and substance P were measured in CSF and compared with morphological findings on MRI and clinical pain scores.

RESULTS

All dogs without clinical signs had symmetrical syringomyelia, whereas in the group with pain, 6 dogs had symmetrical and 9 dogs had asymmetrical syringomyelia. Pain and syringomyelia asymmetry were correlated, and a strong association between pain and dorsal horn involvement of syringomyelia was observed. There was no significant difference between the mean width of the syringomyelia in dogs with or without pain. The concentrations of interleukin-6 and substance P were significantly higher in dogs with neuropathic pain. Tumor necrosis factor alpha was not detected in either group. Concentrations of substance P were significantly higher in dogs with asymmetrical syringomyelia or dorsal horn involvement, whereas interleukin-6 concentrations were not significantly different between groups.

CONCLUSION

Release of interleukin-6 and substance P may initiate proinflammatory effects leading to development of persistent pain in CKCSs with syringomyelia.

Aquaporin-4 expression and blood–spinal cord barrier permeability in canalicular syringomyelia

Object

Noncommunicating canalicular syringomyelia occurs in up to 65% of patients with Chiari malformation Type I. The pathogenesis of this type of syringomyelia is poorly understood and treatment is not always effective. Although it is generally thought that syringomyelia is simply an accumulation of CSF from the subarachnoid space, the pathogenesis is likely to be more complex and may involve cellular and molecular processes. Aquaporin-4 (AQP4) has been implicated in numerous CNS pathological conditions involving fluid accumulation, including spinal cord edema. There is evidence that AQP4 facilitates the removal of extracellular water following vasogenic edema. The aim of this study was to investigate AQP4 expression and the structural and functional integrity of the blood–spinal cord barrier (BSCB) in a model of noncommunicating canalicular syringomyelia.

Methods

A kaolin-induced model of canalicular syringomyelia was used to investigate BSCB permeability and AQP4 expression in 27 adult male Sprague-Dawley rats. Control groups consisted of nonoperated, laminectomy-only, and saline-injected animals. The structural integrity of the BSCB was assessed using immunoreactivity to endothelial barrier antigen. Functional integrity of the BSCB was assessed by extravasation of systemically injected horseradish peroxidase (HRP) at 1, 3, 6, or 12 weeks after surgery. Immunofluorescence was used to assess AQP4 and glial fibrillary acidic protein (GFAP) expression at 12 weeks following syrinx induction.

Results

Extravasation of HRP was evident surrounding the central canal in 11 of 15 animals injected with kaolin, and in 2 of the 5 sham-injected animals. No disruption of the BSCB was observed in laminectomy-only controls. At 12 weeks the tracer leakage was widespread, occurring at every level rostral to the kaolin injection. At this time point there was a decrease in EBA expression in the gray matter surrounding the central canal from C-5 to C-7. Aquaporin-4 was expressed in gray- and white-matter astrocytes, predominantly at the glia limitans interna and externa, and to a lesser extent around neurons and blood vessels, in both control and syrinx animals. Expression of GFAP and APQ4 directly surrounding the central canal in kaolin-injected animals was variable and not significantly different from expression in controls.

Conclusions

This study demonstrated a prolonged disruption of the BSCB directly surrounding the central canal in the experimental model of noncommunicating canalicular syringomyelia. The disruption was widespread at 12 weeks, when central canal dilation was most marked. Loss of integrity of the barrier with fluid entering the interstitial space of the spinal parenchyma may contribute to enlargement of the canal and progression of syringomyelia. Significant changes in AQP4 expression were not observed in this model of canalicular syringomyelia. Further investigation is needed to elucidate whether subtle changes in AQP4 expression occur in canalicular syringomyelia.

A single-center experience with eccentric syringomyelia found with pediatric Chiari I malformation

INTRODUCTION

Eccentric syringes associated with Chiari I malformation have received scant attention in the medical literature. Herein, we describe our experience and long-term outcome in patients with this finding.

MATERIALS AND METHODS

A retrospective analysis of a Chiari I database was performed. Patients known to have an associated syringomyelia were then further analyzed for the type of syrinx present. When an eccentric syrinx was noted, the symptoms and postoperative course of these patients were analyzed.

RESULTS

Of well over 500 operative cases of Chiari I malformation, roughly 70 % (pre-syrinx and minimally dilated central canals were excluded) were found to have an associated syringomyelia. Of these, four patients were found to have an eccentrically positioned syrinx. Three of these cases presented with symptoms referable to the side of the eccentric syrinx. Postoperatively, cases with both a central and eccentrically located syrinx were found to have a greater decrease in the size of the central portion of their syrinx compared to the eccentrically located portion. Symptoms decreased in all patients.

CONCLUSIONS

The minority of our patients with hindbrain-induced syringomyelia were found to have an eccentrically located syrinx. Of these, most will have symptoms localized to the abnormal fluid-filled cavity, and these may not decrease in size as much as centrally located syringes following posterior fossa decompression. However, all symptoms decreased in those operated. Based on the literature, non-hindbrain-induced syringomyelia is more likely to result in an eccentrically placed syrinx. The mechanism for this is yet to be elucidated.

Paroxysmal neuropathic pain in an adolescent female with syringomyelia: a review of literature

Paroxysmal neuropathic pain is an uncommon complaint among pediatric patients visiting the emergency department. It is a rare presentation in children with syringomyelia. Patients with syringomyelia may present with a variety of pain symptoms. It is the site and extension of the syrinx, which determines the character of pain. We report an adolescent with Chiari malformation type 1 with syringomyelia who presented with neuropathic pain, dysesthesia, and absent triceps (C7) reflex. The pertinent literature is reviewed.

Foramen magnum arachnoid cyst induces compression of the spinal cord and syringomyelia: case report and literature review

It is very rare that a foramen magnum arachnoid cyst induces compression of the spinal cord and syringomyelia, and currently there are few treatment experiences available. Here we reported the case of a 43-year-old male patient who admitted to the hospital due to weakness and numbness of all 4 limbs, with difficulty in urination and bowel movement. MRI revealed a foramen magnum arachnoid cyst with associated syringomyelia. Posterior fossa decompression and arachnoid cyst excision were performed. Decompression was fully undertaken during surgery; however, only the posterior wall of the arachnoid cyst was excised, because it was almost impossible to remove the whole arachnoid cyst due to toughness of the cyst and tight adhesion to the spinal cord. Three months after the surgery, MRI showed a reduction in the size of the arachnoid cyst but syrinx still remained. Despite this, the symptoms of the patient were obviously improved compared to before surgery. Thus, for the treatment of foramen magnum arachnoid cyst with compression of the spinal cord and syringomyelia, if the arachnoid cyst could not be completely excised, excision should be performed as much as possible with complete decompression of the posterior fossa, which could result in a satisfying outcome.

Idiopathic syrinx in the pediatric population: a combined center experience

OBJECT

Discovery of a syrinx in a child, without a readily identifiable proximate cause such as a Chiari malformation, tumor, or site of tethering, is often a cause of concern for families and a source of consternation for clinicians. There is a paucity of data describing the natural history of an idiopathic syrinx in the pediatric population. The authors present the combined data of 2 major pediatric neurosurgical centers to describe their experience with this condition.

METHODS

Data were collected at Children's Hospital Boston and St. Louis Children's Hospital according to institutional review board-approved protocols and captured visits over a 2.5-year interval (October 2006-March 2009), with records reviewed if the patient had a preexisting diagnosis of syrinx. Patients were identified by ICD-9 codes derived from departmental databases. All pediatric patients (age < 19 years) in whom idiopathic syrinx had been diagnosed, as defined by MR imaging findings (dilated central canal in the spinal cord of ≥ 1 mm in axial dimension and extending over at least 2 vertebral levels), were included.

RESULTS

Forty-eight patients met the criteria for idiopathic syrinx during this period, and in 32 of them detailed follow-up imaging was available. Discovery of a syrinx was incidental in 6 patients, whereas the others were referred for imaging because of the presence of pain, neurological symptoms, scoliosis, or skin markings. The average age at the first MR imaging session was 9.7 years, with a mean syrinx size of 4 mm (range 1.2-9.4 mm). The majority (52%) of patients had a thoracic syrinx, with the average lesion spanning 7.1 vertebral levels. The average follow-up was 23.8 months (range 2-64 months), and subgroups of patients with < 3 years and ≥ 3 years of follow-up were independently reviewed. Overall, symptoms improved in 34% and worsened in 9%; 57% of the patients remained asymptomatic or stable. Radiographically (in the subgroup of 32 patients with detailed follow-up imaging), syrinx size decreased in 25% of patients, increased in 12.5%, and remained unchanged in 62.5%, with no apparent correlation between change in syrinx size and clinical symptoms.

CONCLUSIONS

Clinically, children with an idiopathic syrinx remained asymptomatic, stable, or improved in 91% of cases. The majority of syringes (87.5%) remained stable or shrank over time, with no apparent correlation between changes in size and changes in symptoms. Although longer follow-up is needed, these data suggest that the natural history of an idiopathic syrinx in children is benign, and that repeated imaging may not be necessary.

[Septic arthritis complicating neuropathic shoulder due to cervical syringomyelia]

One of the main causes of neuropathic osteoarthropathy of the shoulder is cervical syringomyelia. Chronic pain and swelling of the shoulder are the most frequent manifestations, but it occasionally can develop rapid osteoarticular destructive lesions (in less than six weeks), which raise the diagnostic possibility of septic arthritis and some tumours We present the report of two men with septic arthritis of the shoulder associated with neuropathic arthropathy secondary to syringomyelia. Both patients presented with sudden shoulder pain exacerbated by either passive or active joint movements, malaise and fever. The first patient, a 39-year-old man, suffered left shoulder arthritis due to Staphylococcus aureus. The second patient, a 59-year-old man presented with right shoulder arthritis caused by to Staphylococcus epidermidis. The last microorganism also was isolated in three blood cultures. Infection should certainly be considered as a possible complication of the natural history of the neuropathic shoulder.

Defining the line between hydromyelia and syringomyelia. A differentiation is possible based on electrophysiological and magnetic resonance imaging studies

PURPOSE

With the frequent use of magnetic resonance imaging (MRI), patients with subtle and diffuse symptoms due to small syrinx cavities increasingly present to neurosurgical care. In this respect, a dilated central canal, hydromyelia, must be separated from patients with true syringomyelia with an underlying disorder, as they do not share clinical and radiological features. We hypothesize that a differentiation of these two entities with distinct diagnostic tools is possible.

METHODS

To describe the entity of hydromyelia, we excluded all patients from the syringomyelia database (n = 142) with any obvious cause of a syringomyelia, any objective neurological deficits on clinical examination, pathological results on electrophysiological monitoring (SSEP, MEP, silent periods) or a widening of the spinal cord cavity of more than 6 mm on MRI [routine acquisitions with FLAIR, T1/T2-weighted images, Cine and CISS (constructive interference in steady-state) studies]. Life quality was assessed through SF-36 questionnaires and an individualized questionnaire for the clinical history, pain and alternative therapies.

RESULTS

Forty patients (15 males/25 females) matched the criteria of a hydromyelia. With a mean age of 36.7 years (range 11-62), they almost all presented with pain (79%) or dysaesthesia of the limbs, with some having been an incidental finding (10%). Over a follow-up time of 36.9 months (range 6-93) there was no neurological or radiological deterioration.

CONCLUSIONS

Patients with a hydromyelia do not share clinical or radiological characteristics with patients harbouring a true syringomyelia. As hydromyelia does not represent a disease with an underlying pathology, no clinical or radiological progression has been seen. With sophisticated diagnostic tools to rule out any pathology this subset of patients can be identified.

Long-term follow-up of Chiari-related syringomyelia in adults: analysis of 157 surgically treated cases

OBJECTIVE

To determine the long-term outcome of surgically treated Chiari-related syringomyelia.

METHODS

The medical charts of 157 consecutive surgically treated patients with Chiari-related syringomyelia were retrospectively analyzed. Factors predicting outcome, either clinical or radiological, are discussed, and our results are compared with those of other large series in the literature.

RESULTS

The study included 74 men and 83 women (age range, 16-75 years; mean age at surgery, 38.3 years). Pain and sensory disturbance were the most frequent initial symptoms. The average duration of preoperative symptoms was 8.2 years. The follow-up period ranged from 82 to 204 months (median, 88 months). At the end of the study, 99 patients (63.06%) had improved, 48 (30.58%) had stabilized, 9 (5.73%) had worsened, and 1 (0.63%) had died during the postoperative period. Factors predicting improvement or stabilization were young age at the time of surgery and clinical signs of paroxysmal intracranial hypertension. Factors associated with a poor outcome were older age at the time of surgery, arachnoiditis, and a clinical feature of long-tract impairment syndrome. The presence of arachnoiditis or of basilar invagination was associated with poor clinical presentation (P = 0.05 and 0.0001, respectively). The extent of the cyst on postoperative magnetic resonance imaging was a predictor of poor clinical outcome (P = 0.002).

CONCLUSION

Our results confirmed that surgery is an effective and safe treatment of Chiari-related syringomyelia, with a 90% chance of long-term stabilization or improvement on average. Surgery should be proposed as soon as possible in patients with clearly progressing clinical features.

CHIARI I MALFORMATION AS A CAUSE OF TRIGEMINAL NEURALGIA

OBJECTIVE

Trigeminal neuralgia (TN) is usually associated with vascular compression of the trigeminal nerve, but some cases are associated with central lesions such as tumors, aneurysms, or arteriovenous malformations. In this article, we report the 19th case of TN associated with Chiari I malformation and review clinical outcomes and pathophysiology.

CLINICAL PRESENTATION

A 63-year-old right-handed man initially presented in 1993 with left-sided lancinating facial pain in the V2 distribution of the trigeminal nerve; the pain was triggered by certain movements, tactile stimulation, or a hot shower. Magnetic resonance imaging revealed a Chiari I malformation associated with a syrinx from C1 to C3.

INTERVENTION

The patient underwent uncomplicated suboccipital craniectomy, C1 laminectomy, and duraplasty for Chiari decompression. Postoperatively, his pain resolved over a period of 1 year.

CONCLUSION

Chiari I malformation has been found to be associated with TN in 19 cases in the English-language literature. In patients refractory to medical treatment, suboccipital decompression leads to resolution of pain in about two-thirds of patients. Potential mechanisms for the pathogenesis of TN in the setting of Chiari I malformation are discussed. Chiari I malformation is important to consider as a rare cause of TN that responds to surgical therapy.

Neuronal and vascular biomarkers in syringomyelia: investigations using longitudinal MRI

Aims: Syringomyelia is a formation of fluid-filled cavities in the spinal cord, caused by a number of situations including trauma. To understand the origin and progression of syringomyelia, animal models were developed to mimick the condition and computer models were implemented for performing numerical analysis. This article characterizes the neuropathological stages of a contused spinal cord before and after the syringomyelia formation using longitudinal in vivo MRI. Materials & methods: Rat was subject to a contusion-type spinal cord injury (SCI) at the T12 level. MRI data were gathered on post-injury days 3, 14, 28, 72, 94 and 404 using a 9.4 T scanner. In addition, neurobehavioral tests were performed prior to the scans on these days. Results: Pathological consequences of SCI included significant edema and, to a lesser degree, hemorrhage in the acute phase, followed by neuronal loss, tissue alterations and vascular changes in the late stages. The images from the post-injury day 14 indicated shrinkage of the injured tissue and occlusion of the central canal. Subsequently, syringomyelia was initiated cranial to the occlusion and the fluid-filled cavities enlarged with time. The neurologic deficits of the injured rat also worsened over time. Conclusion: The inflammatory, but not the hemostatic, component seems to be a prerequisite for syringomyelia proceeding contusive SCI and abnormal flow of the cerebrospinal fluid (CSF) is likely the main factor. Bioimaging markers from high-resolution MRI sensitized to inflammation and CSF flow may be used for early detection of syringomyelia and assessing its prognosis.

Chiari malformation, cervical disc prolapse and syringomyelia--always think twice

We present the case of a 36-year-old man with neck pain and parasthesia of both upper limbs. Magnetic resonance imaging demonstrated a cervical disc protrusion with spinal cord compression, a Chiari I malformation and cervical syringomyelia. On clinical grounds it was suspected that the cervical stenosis was the symptomatic pathology and an anterior cervical decompression was performed, followed by arthroplasty. Post-operative imaging demonstrated adequate canal decompression, preserved cervical mobility and near-complete resolution of the syrinx. Syringomyelia has a multitude of causes and synchronous pathology can occur. Cervical spondylosis is infrequently associated with syringomyelia. Chiari I malformations are increasingly incidentally detected and asymptomatic. This first report of arthroplasty for cervical spondylosis associated with syringomyelia adds to the growing body of experience with this new technology.

Concurrent syringomyelia and intradural extramedullary tuberculoma as late complications of tuberculous meningitis

Tuberculous meningitis (TBM) is a common presentation of extrapulmonary tuberculosis. TBM is associated with many complications. However, concurrent syringomyelia and intradural extramedullary tuberculoma occurring in a patient treated for TBM is rare. Only one such case has been reported earlier. A 27-year-old woman presented with paraparesis of 2 months duration. She had been treated for TBM 8 months earlier. She was found to have an extensive syringomyelia from C2 to the conus medullaris and an intradural extramedullary tuberculoma at the lower thoracic levels. At surgery, a thick, granulomatous lesion was found in the intradural extramedullary plane. Following excision of the granulomatous lesion, a syringostomy was done. The patient was treated with antituberculous drugs and steroids. Six months after treatment, there was no significant change in her neurological status. Concurrent syringomyelia and intradural extramedullary tuberculoma should be entertained in the differential diagnosis when a patient presents with myelopathy following TBM. The pathogenesis of syringomyelia in this condition is discussed.

A case of syringomyelia associated with cervical spondylosis

Cervical spondylosis is an extremely common condition causing spinal cord compression, and yet it very rarely causes secondary syrinx formation. We report a case of cervical spondylosis with associated syringomyelia and review the possible pathogenesis of this condition.

[Imaging follow-up of post-traumatic myelomalacia]

The authors report a case of secondary worsening of neurological symptoms in a patient 2 months after cord injury at T5 causing paraplegia. The MRI showed myeolomalacia, which appears as cord oedema, located in the grey matter, extending increasingly from the initial lesion (eighth thoracic vertebra) to the bulb. This cord lesion known as grey matter cytotoxic oedema, evolved into a syringomyelic cavity.

An unusual presentation and resolution of syringomyelia after cervical spine injury

✓ The authors describe a case of noncommunicating syringomyelia associated with Chiari malformation Type I in a patient in whom acute symptomatic exacerbation occurred following cervical spine trauma. Surgical stabilization and realignment of the spine resulted in marked resolution of the neurological abnormalities, and subsequent magnetic resonance imaging demonstrated persistent collapse of the syrinx. The authors review the various factors in the pathogenesis of this unusual sequence of events.

Chiari type I malformations in adults: a morphometric analysis of the posterior cranial fossa

OBJECTIVE

Chiari type I malformation (CMI) is a congenital disorder characterized by caudal displacement of the cerebellar tonsils through the foramen magnum into the spinal canal. Recent studies suggest that overcrowding in the posterior cranial fossa (PCF) because of underdeveloped bony structures in the intrauterine life is the main cause of this malformation. For this reason, the authors want to contribute to the current literature, which focuses on bone abnormalities in the PCF in patients with CMIs.

METHODS

We examined a retrospective cohort of 60 adult patients with CMIs, and multiple measurements were made on magnetic resonance imaging. The results were compared to 30 healthy adult control subjects. Mann-Whitney U test was used as a statistical method.

RESULTS

All measurements except mean anteroposterior diameter of the foramen magnum were reduced in patients compared to control. An increase in the anteroposterior mid-sagittal distance of the foramen magnum in patients reached statistically significant difference compared to control. All patients had tonsillar herniation at least 5 mm below the plane of the foramen magnum. Chiari type I malformation in this study was associated with syringomyelia in 46 patients.

CONCLUSION

This study with a limited number of patients suggests that the bony components of the PCF are not developed fully, supporting the current concept that CMI is a disorder of the para-axial mesoderm.

The Origins of Syringomyelia: Numerical Models of Fluid/Structure Interactions in the Spinal Cord

A two-dimensional axi-symmetric numerical model is constructed of the spinal cord, consisting of elastic cord tissue surrounded by aqueous cerebrospinal fluid, in turn surrounded by elastic dura. The geometric and elastic parameters are simplified but of realistic order, compared with existing measurements. A distal reflecting site models scar tissue formed by earlier trauma to the cord, which is commonly associated with syrinx formation. Transients equivalent to both arterial pulsation and percussive coughing are used to excite wave propagation. Propagation is investigated in this model and one with a central canal down the middle of the cord tissue, and in further idealized versions of it, including a model with no cord, one with a rigid cord, one with a rigid dura, and a double-length untapered variant of the rigid-dura model. Analytical predictions for axial and radial wave-speeds in these different situations are compared with, and used to explain, the numerical outcomes. We find that the anatomic circumstances of the spinal cerebrospinal fluid cavity probably do not allow for significant wave steepening phenomena. The results indicate that wave propagation in the real cord is set by the elastic properties of both the cord tissue and the confining dura mater, fat, and bone. The central canal does not influence the wave propagation significantly.

Effects of surgery on the sensory deficits of syringomyelia and predictors of outcome: a long term prospective study

OBJECTIVE

To quantify the effects of surgery on the thermal deficits of syringomyelia and assess the predictors for such effects.

METHODS

The subjects were 16 consecutive patients (12 men, 4 women; mean (SD) duration of sensory symptoms, 5.1 (4.5) years) presenting with the typical symptoms of syringomyelia related to Chiari I malformation or trauma, and requiring surgical treatment. They were evaluated before surgery, then at six months and two years. Sensory evaluation included determination of the extent of thermal deficits and quantitative assessment of thermal, mechanical, vibration detection, and pain thresholds. Neuropathic pain intensity was evaluated on visual analogue scales. Magnetic resonance imaging was done before and after surgery to measure syrinx dimensions.

RESULTS

The magnitude and extent of thermal deficits improved in a subgroup of patients and this was best predicted by the duration of sensory symptoms: patients operated on less than two years after the onset of their symptoms tended to improve, while those operated on later were stabilised or deteriorated slightly. The effect of surgery on thermal deficits was correlated with the duration of sensory symptoms. Surgery also affected vibration deficits in patients with the Chiari malformation, neuropathic pain on effort, and syrinx dimensions.

CONCLUSIONS

The duration of sensory deficits is the best predictive factor of the efficacy of surgery for the thermal symptoms of syringomyelia. Early surgery is required if these deficits are to be minimised.

Retrospective study of surgery-related outcomes in patients with syringomyelia associated with Chiari I malformation: clinical significance of changes in the size and localization of syrinx on pain relief

Object. Pain is one of the major symptoms in patients with syringomyelia; however, its origin is not fully understood, and postoperative improvement of pain is difficult to predict. The objectives of this study were to assess the surgery-related results obtained in patients who underwent treatment for syringomyelia associated with Chiari I malformation, particularly related to pain status, and to identify factors that may influence improvement in postoperative pain by comparing pre- and postoperative magnetic resonance (MR) imaging findings.

Methods. The correlation between pre- and postoperative changes in the size and the location of the syrinx and pain improvement was investigated in 25 patients. The shapes of the syringes were classified into three types: central, enlarged, and deviated. In most cases in which the syrinx deviated toward the posterolateral aspect of the spinal cord at the level corresponding to dermatomal distribution of preoperative pain, the lesion remained at the same position postoperatively, and improvement in pain was poor. On the other hand, enlarged-type syringes were the most frequently observed prior to surgery, exhibited diverse changes postoperatively, and improvement in pain status was difficult to predict. When postoperative MR imaging revealed a transformation to the deviated type, poor pain improvement was noted.

Conclusions. Neurons in the dorsal horn were thought to be involved in the development of pain as a result of the deafferentiation mechanism in cases of 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.

Slitlike syrinx cavities: a persistent central canal

OBJECT

The authors review their experience in the diagnosis and management of 32 patients with slitlike syrinx cavities.

METHODS

There were 18 men and 14 women with a mean age of 40 years. Presenting symptoms that prompted magnetic resonance (MR) imaging evaluation were mechanical spinal pain (13 patients), radicular pain (seven patients), paresthesia (six patients), numbness (five patients), and muscle spasm (one patient). In 12 patients neurological examination demonstrated normal status, and in the remainder only minimal sensory or motor abnormalities were found. The mean diameter of the syrinx cavity was 2 mm (range 1-5 mm), and on average it covered three vertebral levels. The cavities were limited to the cervical region in 16 patients, the thoracic in 12, and both regions in four patients. The mean follow-up time for changes in clinical condition and repeated MR imaging features were 38 and 32 months, respectively. Thirty-one patients were treated nonoperatively, and one was treated surgically. During the follow-up period clinical improvement was documented in six patients, worsened status in seven, and no change was demonstrated in the clinical status of 19 patients. None of the syrinx cavities changed in size. In 16 patients medical workup revealed alternative diagnoses that were determined to be the true causes of each patient's symptoms.

CONCLUSIONS

Slitlike cavities likely do not represent true syringomyelia but rather remnants of the central canal detected in a small percentage of adults. Review of the authors' experience indicates that these cavities are asymptomatic and are unlikely to change in size. They can be considered an incidental finding, and in many of these patients another condition explaining the patient's symptoms may be found.

Endoscopic Third Ventriculostomy for Treatment of Noncommunicating Syringomyelia Associated with a Chiari I Malformation and Hydrocephalus: Case Report and Pathophysiological Considerations

OBJECTIVE AND IMPORTANCE

A Chiari I malformation associated with syringomyelia and hydrocephalus is a rare condition. We report the successful use of endoscopic third ventriculostomy for the treatment of this pathological entity. The successful use of this technique in such a case has not been previously described, and the results allow us to speculate on the pathophysiological mechanism involved.

CLINICAL PRESENTATION

A 34-year-old woman presented with headaches, a motor deficit of the right upper limb, and gait dyspraxia. Magnetic resonance imaging scans demonstrated dilation of all ventricles, compression of the retrocerebellar cerebrospinal fluid space, downward displacement of the tonsils, and syringomyelia. Syringomyelia involved the cervicodorsal cord below C3, with a syrinx-free segment between C1 and C3 and no enlargement of the rostral part of the central canal.

INTERVENTION

Endoscopic third ventriculostomy resulted in prompt improvement of the clinical symptoms. Postoperative magnetic resonance imaging scans demonstrated shrinkage of the syrinx and return of the cerebellar tonsils to their physiological positions.

CONCLUSION

This experience demonstrates that endoscopic third ventriculostomy, which is a simple, safe technique, may be the treatment of choice for associated Chiari I malformations, hydrocephalus, and syringomyelia (even the noncommunicating type).

Syrinx size and duration of symptoms predict the pace of progressive myelopathy: retrospective analysis of 103 unoperated cases with craniocervical junction malformations and syringomyelia

OBJECTIVE

the clinical course of syringomyelia associated with craniocervical junction abnormalities is variable. About half of the unoperated patients have benign course. This is difficult to explain on the basis of the present pathogenetic theories. Therefore, to understand the mechanism of syrinx progression better, we studied the value of syrinx size, syrinx morphology, and the syrinx/spinal cord size ratio in predicting the rate of progression and the severity of myelopathy in these patients.

METHODS

103 adult patients with syringomyelia associated with Chiari 1 malformation and/or radiographic signs of underdeveloped posterior cranial fossa were clinically and MRI examined. Patients were subdivided according to the type of disease progression. Severity of neurological deficits, and MRI features (the extent of cerebellar tonsillar displacement, anteroposterior diameter of cavities, the spinal cord and cyst/cord ratio and the shape of cavities) were measured.

RESULTS

a significant relationship was found between the mid-sagittal diameter of the syrinxes and the type of disease course; patients with short duration and rapid progression had the largest diameters of cavities, whereas patients with longer duration as well as with slow rate of progression had smaller diameters (chi(2)=28.90, P<0.05; chi(2)=29.89, P<0.01; r=-0.24, P<0.05). In addition, a correlation was found between the anteroposterior diameter of the spinal cord and cyst/cord ratio and the disease duration (r=0.52, P<0.05 and r=0.48, P<0.05, respectively).

CONCLUSIONS

the initial years for the development of symptomatic syringomyelia associated with CCJ malformations are characterized by relatively rapid clinical progression accompanied with distended cavities. In the later periods of unoperated syringomyelia, some patients show delay in the progress of syrinxes accompanied with collapse of cavities, probably either due to a spontaneous formation of drainage between the syrinx and the subarachnoidal space, or due to the restoration of abnormal CSF dynamics at the CCJ level.

Diffusion-weighted imaging of the spinal cord

Spinal cord DWI may be useful in providing information not available with conventional MR imaging. More work, however, is required to explain what the qualitative and quantitative results actually represent. Computer simulations and detailed radiologic-histologic correlations will therefore be necessary.

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.