Elucidating the pathophysiology of syringomyelia

1999 ◽  
Vol 91 (4) ◽  
pp. 553-562 ◽  
Author(s):  
John D. Heiss ◽  
Nicholas Patronas ◽  
Hetty L. DeVroom ◽  
Thomas Shawker ◽  
Robert Ennis ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Subarachnoid Space ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Content Type ◽  
Cine Mr ◽  
Spinal Subarachnoid Space ◽  
Chiari I ◽  
Cerebellar Tonsils ◽  
Fine Print

Object. Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy.Methods. The authors prospectively studied 20 adult patients with both Chiari I malformation and symptomatic syringomyelia. Testing before surgery included the following: clinical examination; evaluation of anatomy by using T1-weighted magnetic resonance (MR) imaging; evaluation of the syrinx and cerebrospinal fluid (CSF) velocity and flow by using phase-contrast cine MR imaging; and evaluation of lumbar and cervical subarachnoid pressure at rest, during the Valsalva maneuver, during jugular compression, and following removal of CSF (CSF compliance measurement). During surgery, cardiac-gated ultrasonography and pressure measurements were obtained from the intracranial, cervical subarachnoid, and lumbar intrathecal spaces and syrinx. Six months after surgery, clinical examinations, MR imaging studies, and CSF pressure recordings were repeated. Clinical examinations and MR imaging studies were repeated annually. For comparison, 18 healthy volunteers underwent T1-weighted MR imaging, cine MR imaging, and cervical and lumbar subarachnoid pressure testing.Compared with healthy volunteers, before surgery, the patients had decreased anteroposterior diameters of the ventral and dorsal CSF spaces at the foramen magnum. In patients, CSF velocity at the foramen magnum was increased, but CSF flow was reduced. Transmission of intracranial pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was partially obstructed. Spinal CSF compliance was reduced, whereas cervical subarachnoid pressure and pulse pressure were increased. Syrinx fluid flowed inferiorly during systole and superiorly during diastole on cine MR imaging. At surgery, the cerebellar tonsils abruptly descended during systole and ascended during diastole, and the upper pole of the syrinx contracted in a manner synchronous with tonsillar descent and with the peak systolic cervical subarachnoid pressure wave. Following surgery, the diameter of the CSF passages at the foramen magnum increased compared with preoperative values, and the maximum flow rate of CSF across the foramen magnum during systole increased. Transmission of pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was normal and cervical subarachnoid mean pressure and pulse pressure decreased to normal. The maximum syrinx diameter decreased on MR imaging in all patients. Cine MR imaging documented reduced velocity and flow of the syrinx fluid. Clinical symptoms and signs improved or remained stable in all patients, and the tonsils resumed a normal shape.Conclusions. The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-1 laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.

scholarly journals Elucidating the pathophysiology of syringomyelia

1999 ◽  
Vol 7 (2) ◽  
pp. E1 ◽  
Author(s):  
John D. Heiss ◽  
Nicholas Patronas ◽  
Hetty L. DeVroom ◽  
Thomas Shawker ◽  
Robert Ennis ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Pulse Pressure ◽  
Subarachnoid Space ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Imaging Studies ◽  
Cine Mr ◽  
Spinal Subarachnoid Space ◽  
Chiari I ◽  
Cerebellar Tonsils

Object Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy. Methods The authors prospectively studied 20 adult patients with both Chiari I malformation and symptomatic syringomyelia. Testing before surgery included the following: clinical examination; evaluation of anatomy by using T1-weighted magnetic resonance (MR) imaging; evaluation of the syrinx and cerebrospinal fluid (CSF) velocity and flow by using phase-contrast cine MR imaging; and evaluation of lumbar and cervical subarachnoid pressure at rest, during the Valsalva maneuver, during jugular compression, and following removal of CSF (CSF compliance measurement). During surgery, cardiac-gated ultrasonography and pressure measurements were obtained from the intracranial, cervical subarachnoid, and lumbar intrathecal spaces and syrinx. Six months after surgery, clinical examinations, MR imaging studies, and CSF pressure recordings were repeated. Clinical examinations and MR imaging studies were repeated annually. For comparison, 18 healthy volunteers underwent T1-weighted MR imaging, cine MR imaging, and cervical and lumbar subarachnoid pressure testing. Compared with healthy volunteers, before surgery, the patients had decreased anteroposterior diameters of the ventral and dorsal CSF spaces at the foramen magnum. In patients, CSF velocity at the foramen magnum was increased, but CSF flow was reduced. Transmission of intracranial pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was partially obstructed. Spinal CSF compliance was reduced, whereas cervical subarachnoid pressure and pulse pressure were increased. Syrinx fluid flowed inferiorly during systole and superiorly during diastole on cine MR imaging. At surgery, the cerebellar tonsils abruptly descended during systole and ascended during diastole, and the upper pole of the syrinx contracted in a manner synchronous with tonsillar descent and with the peak systolic cervical subarachnoid pressure wave. Following surgery, the diameter of the CSF passages at the foramen magnum increased compared with preoperative values, and the maximum flow rate of CSF across the foramen magnum during systole increased. Transmission of pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was normal and cervical subarachnoid mean pressuree and pulse pressure decreased to normal. The maximum syrinx diameter decreased on MR imaging in all patients. Cine MR imaging documented reduced velocity and flow of the syrinx fluid. Clinical symptoms and signs improved or remained stable in all patients, and the tonsils resumed a normal shape. Conclusions The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-1 laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.

“Acquired” Chiari I malformation

1994 ◽  
Vol 80 (6) ◽  
pp. 1099-1102 ◽  
Author(s):  
Paul P. Huang ◽  
Shlomo Constantini
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Chiari I Malformation ◽  
Congenital Defect ◽  
Content Type ◽  
Chiari I ◽  
Gait Abnormalities ◽  
Cerebellar Tonsils ◽  
Tonsillar Descent ◽  
Fine Print

✓ Tonsillar descent of the cerebellum in Chiari I malformations is often considered a congenital defect. A patient is presented in whom magnetic resonance (MR) imaging revealed normally positioned cerebellar tonsils; however, 1 year later MR imaging was repeated for evaluation of gait abnormalities and showed descent of the cerebellar tonsils. This case illustrates worsening symptoms with progressive descent of the cerebellar tonsils and suggests that Chiari I malformations can evolve postnatally.

Inclination of the odontoid process in the pediatric Chiari I malformation

2003 ◽  
Vol 98 (1) ◽  
pp. 43-49 ◽  
Author(s):  
R. Shane Tubbs ◽  
John C. Wellons ◽  
Jeffrey P. Blount ◽  
Paul A. Grabb ◽  
W. Jerry Oakes
Keyword(s):  
Odontoid Process ◽  
Postoperative Outcome ◽  
Craniocervical Junction ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Magnetic Resonance Images ◽  
Posterior Aspect ◽  
Content Type ◽  
Chiari I ◽  
Fine Print

Object. The quantitative analysis of odontoid process angulation has had scant attention in the Chiari I malformation population. In this study the authors sought to elucidate the correlation between posterior angulation of the odontoid process and patients with Chiari I malformation. Methods. Magnetic resonance images of the craniocervical junction obtained in 100 children with Chiari I malformation and in 50 children with normal intracranial anatomy (controls) were analyzed. Specific attention was focused on measuring the degree of angulation of the odontoid process and assigning a score to the various degrees. Postoperative outcome following posterior cranial fossa decompression was then correlated to grades of angulation. Other measurements included midsagittal lengths of the foramen magnum and basiocciput, the authors' institutions' previously documented pB—C2 line (a line drawn perpendicular to one drawn between the basion and the posterior aspect of the C-2 body), level of the obex from a midpoint of the McRae line, and the extent of tonsillar herniation. Higher grades of odontoid angulation (retroflexion) were found to be more frequently associated with syringomyelia and particularly holocord syringes. Higher grades of angulation were more common in female patients and were often found to have obices that were caudally displaced greater than three standard deviations below normal. Conclusions. These results not only confirm prior reports of an increased incidence of a retroflexed odontoid process in Chiari I malformation but quantitatively define grades of inclination. Grades of angulation were not found to correlate with postoperative outcome. It is the authors' hopes that these data add to our current limited understanding of the mechanisms involved in hindbrain herniation.

Tonsillectomy without craniectomy for the management of infantile Chiari I malformation

2002 ◽  
Vol 97 (5) ◽  
pp. 1018-1022 ◽  
Author(s):  
Jorge A. Lazareff ◽  
Marcelo Galarza ◽  
Tooraj Gravori ◽  
Theodore J. Spinks
Keyword(s):  
Failure To Thrive ◽  
Vocal Cord Palsy ◽  
Chiari I Malformation ◽  
Cortical Atrophy ◽  
Limb Weakness ◽  
Content Type ◽  
Time Period ◽  
Chiari I ◽  
Cerebellar Tonsils ◽  
Fine Print

Object. The authors report their experience with 15 pediatric patients who underwent resection or shrinkage of the cerebellar tonsils without craniectomy or laminectomy, for the management of Chiari I malformation. Methods. The procedure was performed in six boys and nine girls with a mean age of 10 years. Thirteen patients presented with the congenital form of this disorder and two patients with Chiari I malformation caused by lumboperitoneal shunting. Clinical complaints included headaches (seven patients), scoliosis (four patients), numbness of the extremities (four patients), and upper-limb weakness (two patients). Two patients presented with failure to thrive and one with vocal cord palsy. Eight patients (six girls and two boys) had syringomyelia. The patients' symptoms had developed within a mean time period of 21 months (range 1–70 months). In all patients the cerebellar tonsils were exposed through a dura mater—arachnoid incision at the occipitoatlantal space. In seven patients the tonsils were resected and in the remaining eight patients the tonsils were shrunk by coagulating their surfaces. All patients improved postoperatively. Gliosis with cortical atrophy was observed in the resected neural tissue. Syringomyelia was reduced in seven of eight patients. The mean length of the follow-up period was 7 months. Conclusions. Removal of herniated cerebellar tonsils can be sufficient for alleviating symptoms in patients with Chiari I malformations.

Rapid development of Chiari I malformation in an infant with Seckel syndrome and craniosynostosis

2003 ◽  
Vol 98 (5) ◽  
pp. 1113-1115 ◽  
Author(s):  
Timothy E. Hopkins ◽  
Stephen J. Haines
Keyword(s):  
Mr Imaging ◽  
Posterior Fossa ◽  
Rapid Development ◽  
Chiari I Malformation ◽  
Tonsillar Herniation ◽  
Seckel Syndrome ◽  
Content Type ◽  
Chiari I ◽  
Csf Diversion ◽  
Fine Print

✓ To illustrate the rapidity with which a child can develop a severe, symptomatic Chiari I malformation, the authors present the case of a 3-month-old infant with Seckel syndrome (microcephaly, micrognathia, craniosynostosis, and multiple other abnormalities) and posterior sagittal and bilateral lambdoid synostosis. The infant underwent magnetic resonance (MR) imaging shortly after birth; the initial image demonstrated the cerebellar tonsils in the posterior fossa, with no herniation. He subsequently developed severe apneic episodes and bradycardia; repeated MR imaging at 3 months demonstrated severe tonsillar herniation with compression of the brainstem. The child underwent posterior fossa remodeling surgery, including release of the posterior sagittal and lambdoid sutures and decompression of the Chiari I malformation. The patient's apnea gradually improved; however, he died of complications of pneumonia and sepsis several weeks later. The authors identified from the literature 21 patients in whom there was a documented MR image or other neuroimage that did not reveal evidence of a Chiari I malformation, followed by a subsequent study with clear documentation of the presence of Chiari I malformation. The interval between the initial study and the development of the tonsillar herniation ranged from 11 days to 18.5 years. In most cases, a lumbar cerebrospinal fluid (CSF) diversion had been performed. This patient developed a severely symptomatic Chiari I malformation during a 3-month period. These reports illustrate that the Chiari I malformation can develop rapidly in the face of increased intracranial pressure, craniosynostosis, and spinal CSF diversion.

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

2004 ◽  
Vol 100 (3) ◽  
pp. 241-244 ◽  
Author(s):  
Masaya Nakamura ◽  
Kazuhiro Chiba ◽  
Takashi Nishizawa ◽  
Hirofumi Maruiwa ◽  
Morio Matsumoto ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Chiari I Malformation ◽  
Preoperative Pain ◽  
Content Type ◽  
Postoperative Changes ◽  
Pain Status ◽  
Chiari I ◽  
Postoperative Improvement ◽  
Pain Improvement ◽  
Fine Print

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.

Acquired Chiari I malformation secondary to spontaneous spinal cerebrospinal fluid leakage and chronic intracranial hypotension syndrome in seven cases

1998 ◽  
Vol 88 (2) ◽  
pp. 237-242 ◽  
Author(s):  
John L. D. Atkinson ◽  
Brian G. Weinshenker ◽  
Gary M. Miller ◽  
David G. Piepgras ◽  
Bahram Mokri
Keyword(s):  
Cerebrospinal Fluid ◽  
Intracranial Hypotension ◽  
Chiari I Malformation ◽  
Csf Leak ◽  
Cerebrospinal Fluid Leakage ◽  
Content Type ◽  
Intracranial Hypotension Syndrome ◽  
Csf Leakage ◽  
Chiari I ◽  
Fine Print

Object. Spontaneous spinal cerebrospinal fluid (CSF) leakage with development of the intracranial hypotension syndrome and acquired Chiari I malformation due to lumbar spinal CSF diversion procedures have both been well described. However, concomitant presentation of both syndromes has rarely been reported. The object of this paper is to present data in seven cases in which both syndromes were present. Three illustrative cases are reported in detail. Methods. The authors describe seven symptomatic cases of spontaneous spinal CSF leakage with chronic intracranial hypotension syndrome in which magnetic resonance (MR) images depicted dural enhancement, brain sagging, loss of CSF cisterns, and acquired Chiari I malformation. Conclusions. This subtype of intracranial hypotension syndrome probably results from chronic spinal drainage of CSF or high-flow CSF shunting and subsequent loss of brain buoyancy that results in brain settling and herniation of hindbrain structures through the foramen magnum. Of 35 cases of spontaneous spinal CSF leakage identified in the authors' practice over the last decade, MR imaging evidence of acquired Chiari I malformation has been shown in seven. Not to be confused with idiopathic Chiari I malformation, ideal therapy requires recognition of the syndrome and treatment directed to the site of the spinal CSF leak.

Syrinx shunt to posterior fossa cisterns (syringocisternostomy) for bypassing obstructions of upper cervical theca

1992 ◽  
Vol 77 (6) ◽  
pp. 871-874 ◽  
Author(s):  
Thomas H. Milhorat ◽  
Walter D. Johnson ◽  
John I. Miller
Keyword(s):  
Posterior Fossa ◽  
Symptomatic Improvement ◽  
Foramen Magnum ◽  
Content Type ◽  
Results Of Treatment ◽  
Spinal Subarachnoid Space ◽  
Upper Cervical ◽  
Spinal Arachnoiditis ◽  
Chiari I

✓ Syrinx shunts to the spinal subarachnoid space are likely to fail if the cerebrospinal fluid pathways rostral to the syrinx are blocked. To bypass obstructions at or below the level of the foramen magnum, a technique was developed for shunting the syrinx to the posterior fossa cisterns, termed “syringocisternostomy.” Syrinxes were shunted to the cisterna magna in two patients with spinal arachnoiditis and to the cerebellopontine angle cistern in four patients with Chiari I malformations. There was symptomatic improvement and collapse of the syrinx in each case, with no complications or recurrences over a follow-up interval of 14 to 27 months (average 20.3 months). The surgical technique and results of treatment are described.

Chiari Malformation with Syringomyelia

2019 ◽  
pp. 57-64
Author(s):  
Yiping Li ◽  
Bermans J. Iskandar
Keyword(s):  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Neurological Deficits ◽  
Csf Leakage ◽  
Craniocervical Instability ◽  
Chiari I ◽  
Spine Mri ◽  
Operative Monitoring ◽  
Associated Abnormalities ◽  
Cerebellar Tonsils

Chiari I malformation (CIM) is defined by pathological herniation of the cerebellar tonsils below the foramen magnum. Operative intervention for CIM is generally undertaken to treat neurological deficits associated with tonsillar herniation or with associated syringomyelia. A complete brain and spine MRI is indicated to rule out associated abnormalities and to identify and the presence and extent of syringomyelia. The type of surgical decompression remains controversial but may include bone-only decompression, bony decompression followed by duraplasty, and bony decompression followed by duraplasty and tonsillar shrinkage. Post-operative monitoring for CSF leakage, inadequate decompression, subtle chronic craniocervical instability, and hydrocephalus is critical.

Ventricular perfusion in cats with kaolin-induced hydrocephalus

1974 ◽  
Vol 41 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Howard M. Eisenberg ◽  
James E. McLennan ◽  
Keasley Welch
Keyword(s):  
Spinal Cord ◽  
Subarachnoid Space ◽  
Central Canal ◽  
Ventricular System ◽  
Ventricular Pressure ◽  
Content Type ◽  
Lateral Ventricles ◽  
Spinal Subarachnoid Space ◽  
Wide Range ◽  
Fine Print

✓ Cats were made hydrocephalic by cisternal instillation of kaolin. Three to 8 weeks later it was found by perfusion between the ventricular system and the spinal subarachnoid space that communication had been reestablished through a demonstrably dilated central canal of the spinal cord. Absorption of fluid from the ventricular system, measured both by ventriculospinal perfusion and, after ligation of the spinal cord, by perfusion between the lateral ventricles, was found to be indistinguishable from zero over a wide range of ventricular pressure.

Sign in / Sign up

Export Citation Format

Share Document