Detection of locomotion deficit in a post-traumatic syringomyelia rat model using automated gait analysis technique

Syringomyelia (SM) is a spinal cord disorder in which a cyst (syrinx) filled with fluid forms in the spinal cord post-injury/disease, in patients syrinx symptoms include loss of pain and temperature sensation or locomotion deficit. Currently, there are no small animal models and connected tools to help study the functional impacts of SM. The objective of this study was to determine the detectability of subtle locomotion deficits due to syrinx formation/expansion in post-traumatic syringomyelia (PTSM) rat model using the recently reported method of Gait Analysis Instrumentation, and Technology Optimized for Rodents (GAITOR) with Automated Gait Analysis Through Hues and Areas (AGATHA) technique. First videos of the rats were collected while walking in an arena (using GAITOR) followed by extracting meaningful locomotion information from collected videos using AGATHA protocol. PTSM injured rats demonstrated detectable locomotion deficits in terms of duty factor imbalance, paw placement accuracy, step contact width, stride length, and phase dispersion parameters compared to uninjured rats due to SM. We concluded that this technique could detect mild and subtle locomotion deficits associated with PTSM injury, which also in future work could be used further to monitor locomotion responses after different treatment strategies for SM.

Peripheral nerve hyperexcitability

Neuromyotonic and myokymic discharges are abnormal electrical muscular discharges caused by ectopic discharges from motor axons and represent the hallmarks of peripheral nerve hyperexcitability. Neuromyotonic discharges are specific for peripheral nerve hyperexcitability syndromes, whereas myokymic discharges may occur either focally or in a more generalized fashion in many other peripheral nerve disorders. Isaacs syndrome and Morvan syndrome are rare acquired peripheral nerve hyperexcitability disorders that share common clinical features and are often associated with elevated voltage-gated potassium channel-complex antibodies. Central nervous system symptomatology is more common in Morvan syndrome, which also overlaps with limbic encephalitis. Cramp-fasciculation syndrome, a more common syndrome, may represent a milder form of peripheral nerve hyperexcitability. Peripheral nerve hyperexcitability syndromes should be distinguished from stiff person syndrome, myotonic disorders, and rippling muscle disease. When severe, Isaacs syndrome and Morvan syndrome may be disabling but often respond to membrane-stabilizing drugs and immunomodulatory treatments. The electrophysiologic features of these disorders are described.

On the Pathogenesis of Syringomyelia: A Review

Discussion of the pathogenesis of syringomyelia involves considering the origin of the fluid and also the forces which cause that fluid to break down the structure of the cord. When cerebrospinal fluid (CSF) appears to be the destructive element, it commonly enters through a patent central canal running from the fourth ventricle to the inside of the syrinx. In both clinical and experimental situations pressure differences may be measured which suck on the hindbrain, particularly the cerebellar tonsils, producing deformities. These pressure differences may also suck fluid into the syrinx. In other cases, even when a communication does not appear to be patent, the hindbrain abnormalities are usually present and suck effect may usually be demonstrated and its correction be accompanied by clinical improvement. Other sources of fluid within a syrinx include liquefaction of haematomata after traumatic paraplegia and transudation of fluid from intrinsic spinal tumours. Once fluid is present within a cord cavity it may pulsate upwards and downwards in response to fluid movements in the subarachnoid space, the most energetic of which result from venous influences. Such movement, ‘slosh’, may cause the cavities to extend at either end giving rise to upward and downward extension from a post-traumatic cord cyst and sometimes to syringobulbia. Cord ischaemia, venous congestion and transport of fluid along perivascular spaces may all play a part in the maintainance of cord cavities or the progression of the clinical disabilities.

Functional Impairments in a Patient with Morvan Syndrome: A Case Presentation

A 48-year-old man with lung squamous cell carcinoma was admitted to acute care with cognitive impairment after recent chemotherapy. He developed myoclonus, ataxia, agitation, and visual hallucinations. Morvan syndrome, a rare voltage-gated potassium channel antibody disorder characterized by neuromyotonia with central nervous system dysfunction, was eventually diagnosed. He received plasmapheresis and was admitted to inpatient rehabilitation, where he safely participated in therapies. By focusing on neuromuscular rehabilitation, balance training, fine motor skills, and cognitive retraining emphasizing skills relevant to the patient's premorbid cognitive activities, the patient demonstrated significant functional improvement, decreasing the burden of care of his caregivers.

LEVEL OF EVIDENCE

V.

Misdiagnosed syrinx in a patient with neuroschisis and Klippel-Feil syndrome: case report

INTRODUCTION

Patients with Klippel-Feil syndrome can present with a myriad of symptoms and imaging findings. Herein, we present a case of Klippel-Feil syndrome that was initially misdiagnosed with syringomyelia. We review this case and discuss the imaging findings.

CONCLUSIONS

Neuoroschisis should be suspected in patients with Klippel-Feil syndrome and differentiated from syringomyelia.

Cavalier King Charles Spaniels with Chiari-like malformation and Syringomyelia have increased variability of spatio-temporal gait characteristics

BACKGROUND

Chiari-like malformation in the Cavalier King Charles Spaniel is a herniation of the cerebellum and brainstem into or through the foramen magnum. This condition predisposes to Syringomyelia; fluid filled syrinxes within the spinal cord. The resulting pathology in spinal cord and cerebellum create neuropathic pain and changes in gait. This study aims to quantify the changes in gait for Cavalier King Charles Spaniel with Chiari-like malformation and Syringomyelia.

METHODS

We compared Cavalier King Charles Spaniel with Chiari-like malformation with (n = 9) and without (n = 8) Syringomyelia to Border Terriers (n = 8). Two video cameras and manual tracking was used to quantify gait parameters.

RESULTS AND CONCLUSIONS

We found a significant increase in coefficient of variation for the spatio-temporal characteristics and ipsilateral distance between paws and a wider base of support in the thoracic limbs but not in the pelvic limbs for Cavalier King Charles Spaniels compared with the border terrier.

Arnold Chiari Malformation With Sponastrime (Spondylar and Nasal Changes, With Striations of the Metaphyses) Dysplasia: A Case Report

SPOndylar and NAsal changes, with STRIations of the Metaphyses (SPONASTRIME) dysplasia (SD) is a dwarfing autosomal recessive syndrome, characterized by a variety of clinical and radiographic features, which form the basis for diagnosis. We describe the presentation of an Arnold Chiari malformation in a patient with a clinical diagnosis of SD. The malformation was successfully treated by decompression of the foramen magnum and elevation of the cerebellum, with complete resolution of pain.We report a rare case of Arnold Chiari malformation in a patient presenting with clinical and radiographic features strongly suggestive of SD and be successfully treated.

Results of surgical treatment of syringomyelia associated with Chiari 1 malformation. An analysis of 125 cases

The rate of Chiari malformation (CM) in a population ranges from 3 to 8 per 100,000 population. In 62-80% of cases, CM is accompanied by the development of syringomyelia (SM) at various levels. The clinical picture in these patients is a combination of CM and SM manifestations; however, SM symptoms often prevail, which creates some problems in the diagnosis of the disease and in the choice of optimal treatment.

OBJECTIVE

On the basis of our own experience of surgical interventions, we aimed to clarify the indications for surgical treatment of SM associated with CM and to determine the optimal amount of surgery and the criteria for evaluation of treatment outcomes.

MATERIAL AND METHODS

Two hundred twenty five patients with a combination of syringomyelia and Chiari 1 malformation were examined in the period from 2011 to February 2015. Of them, 125 patients were operated on. The mean age of the operated patients was 56±8 years. The mean time from the appearance of the first signs of the disease to surgery was 75±82 months. All operations were performed by a single surgeon. The operations were carried out in the half-sitting (89.6%) or prone (10.4%) position. The operation included sparing suboccipital craniectomy, C1 arch resection, recovery of the cerebrospinal fluid (CSF) circulation along the posterior surface of the cerebellum, and reconstruction of the dura mater in the craniovertebral junction region.

RESULTS

Exploration of the arachnoid mater of the cisterna magna after dura opening revealed no arachnopathy in 78 (62.4%) patients (Chiari 0 malformation according to Klekamp). The type 1 arachnopathy (by Klekamp) was detected in 31 patients (24.8%), and the type 2 arachnopathy was observed in 16 (12.8%). The condition of 109 (88%) patients was evaluated one year after the surgery. Sixty one (56%) patients had partial or complete regression of preoperative neurological symptoms. The disease stopped progressing in 44 patients (40%). The disease was progressing in 4 (3.7%) patients. No recurrence of a CSF circulation disturbance at the craniovertebral level was observed during follow-up. Early postoperative complications occurred in 4 (3.2%) patients: wound CSF leakage in 1 (0.8%) patient, acute epidural hematoma in 1 (0.8%) patient, and aseptic meningitis in 2 (1.6%) patients. Temporary deteriorations in the condition (headache worsening, meteosensitivity) were detected in 11 (8.9%) patients. These symptoms regressed by the end of the 1st postoperative month. There were no deaths.

CONCLUSIONS

The indication for surgery in patients with a combination of CM and SM is the presence of neurological symptoms associated with syringomyelia and their progression as well as headache caused by herniation of the cerebellar tonsils, which significantly deteriorates the patient's quality of life. The main criteria for evaluating the efficacy of treatment include stabilization of the clinical symptoms and/or improvement in the patient condition. Suboccipital craniectomy followed by reconstruction of the dura mater and recovery of the CSF circulation in the craniovertebral region is an effective treatment of syringomyelia associated with Chiari 1 malformation.

[Monitoring of Somatosensory Evoked Potentials during Foramen Magnum Decompression of Chiari Malformation Type I Complicated with Syringomyelia: A Report of Two Cases]

Few reports exist on anesthetic management for foramen magnum decompression (FMD) of Chiari malformation type I (CM I) complicated with syringomyelia. In two such cases we monitored somatosensory evoked potentials (SEP). Case 1 : A 40-year-old woman presented with occipital headache and nuchal pain for 2 months; numbness and muscular weakness of bilateral upper limbs for a month. Magnetic resonance imaging (MRI) scan showed CM I complicated with syringomyelia. Case 2 : A 32-year-old man presented with numbness and muscular weakness of bilateral upper limbs for 5 months; numbness and muscular weakness of lower limbs for 2 months. MRI scan showed CM I complicated with syringomyelia. They underwent FMD. In both cases, general anesthesia was induced with remifentanil, propofol and rocuronium, and was maintained with oxygen, air, remifentanil and propofol. Moreover, we monitored SEP. Their operative courses were uneventful. In case 1, SEP latency became shorter after FMD. Her preoperative neurologic symptoms disappeared on first postoperative day. In contrast there was no change of SEP latency after FMD in case 2. His preoperative neurologic symptoms showed no change on fifth postoperative day. SEP monitoring may be a useful index for prediction of early recovery of neurologic symptoms after FMD.

The impact of spinal cord nerve roots and denticulate ligaments on cerebrospinal fluid dynamics in the cervical spine

Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role in syringomyelia, Chiari I malformation (CM), and a role in intrathecal drug delivery. Yet, the impact that fine anatomical structures, including nerve roots and denticulate ligaments (NRDL), have on SSS CSF dynamics is not clear. In the present study we assessed the impact of NRDL on CSF dynamics in the cervical SSS. The 3D geometry of the cervical SSS was reconstructed based on manual segmentation of MRI images of a healthy volunteer and a patient with CM. Idealized NRDL were designed and added to each of the geometries based on in vivo measurments in the literature and confirmation by a neuroanatomist. CFD simulations were performed for the healthy and patient case with and without NRDL included. Our results showed that the NRDL had an important impact on CSF dynamics in terms of velocity field and flow patterns. However, pressure distribution was not altered greatly although the NRDL cases required a larger pressure gradient to maintain the same flow. Also, the NRDL did not alter CSF dynamics to a great degree in the SSS from the foramen magnum to the C1 level for the healthy subject and CM patient with mild tonsillar herniation (∼6 mm). Overall, the NRDL increased fluid mixing phenomena and resulted in a more complex flow field. Comparison of the streamlines of CSF flow revealed that the presence of NRDL lead to the formation of vortical structures and remarkably increased the local mixing of the CSF throughout the SSS.

[Brainstem auditory evoked potentials and somatosensory evoked potentials in Chiari malformation]

INTRODUCTION

Chiari malformations (CM) include a series of congenital anomalies involving the descent of the cerebellar tonsils below the foramen magnum, which may be associated with compression in the brainstem, upper spinal cord, and cranial nerves, consequently altering the responses of brainstem auditory evoked potentials (BAEP) and somatosensory evoked potentials (SSEP). However, only a small number of authors have described the indications of these tests in CM, and study groups to date have been small and heterogeneous.

AIM

To review the results of BAEPs and SSEPs in published studies of patients with Chiari type 1 malformation (CM-1) or Chiari type 2 malformation (CM-2) as well as the indications of both tests in the diagnosis, treatment, and monitoring of both diseases, especially CM-1.

DEVELOPMENT

We present a review article analyzing data from all published studies in Medline starting in 1966, located through PubMed, using combinations of the following keywords: 'Chiari malformation', 'Arnold-Chiari malformation', 'Chiari type 1 malformation', 'Arnold-Chiari type 1 malformation', 'evoked potentials', 'brainstem auditory evoked potentials' and 'somatosensory evoked potentials' as well as records of patients with CM-1 from the neurosurgery and neurophysiology departments at the Hospital Universitari Vall d'Hebron.

CONCLUSIONS

Common findings of SSEP are a reduction in cortical amplitude from the posterior tibial nerve, a reduction or absence of cervical median nerve potential, and an increased N13-N20 interval. In BAEP, the most frequent findings are an increased I-V interval and a peripheral or cochlear auditory disturbance.

Computational fluid dynamics modelling of cerebrospinal fluid pressure in Chiari malformation and syringomyelia

The pathogenesis of syringomyelia in association with Chiari malformation (CM) is unclear. Studies of patients with CM have shown alterations in the CSF velocity profile and these could contribute to syrinx development or enlargement. Few studies have considered the fluid mechanics of CM patients with and without syringomyelia separately. Three subject-specific CFD models were developed for a normal participant, a CM patient with syringomyelia and a CM patient without syringomyelia. Model geometries, CSF flow rate data and CSF velocity validation data were collected from MRI scans of the 3 subjects. The predicted peak CSF pressure was compared for the 3 models. An extension of the study performed geometry and flow substitution to investigate the relative effects of anatomy and CSF flow profile on resulting spinal CSF pressure. Based on 50 monitoring locations for each of the models, the CM models had significantly higher magnitude (p<0.01) peak CSF pressure compared with normal. When using the same CSF input flow waveform, changing the upper spinal geometry changed the magnitude of the CSF pressure gradient, and when using the same upper spinal geometry, changing the input flow waveform changed the timing of the peak pressure. This study may assist in understanding syringomyelia mechanisms and relative effects of CSF velocity profile and spinal geometry on CSF pressure.

Intraoperative neurophysiologic monitoring during syringomyelia surgery: lessons from a series of 13 patients

BACKGROUND

Avoiding iatrogenic neurological injury during spinal cord surgery is crucially important. Intraoperative neurological monitoring (INM) has been widely used in a variety of spinal surgeries as a means of reducing the risk of intraoperative neurological insults. This study evaluates the benefits of INM specifically in spinal procedures for treatment of syringomyelia.

METHODS

Thirteen patients who underwent surgery for syrinx drainage with the assistance of INM were included in this study. In all patients both somatosensory-evoked potentials (SSEP) and motor-evoked potentials (MEP) were monitored. INM data and perioperative neurological evaluations were both recorded and analyzed.

RESULTS

Eleven patients underwent syringo-subarachnoid shunt (SSAS) surgery. One patient underwent syrinx drainage and foramen magnum decompression (FMD). One patient underwent syringo-pleural shunt (SPA) surgery. Baseline MEP and SSEP were recordable at the beginning of surgery in 11 patients (>84 %). In the other two cases, baseline data from specific INM modalities were absent, correlating with the antecedent neurologic symptomotology. Two patients exhibited significant intraoperative changes in MEP data that influenced the course of surgery and prompted removal or re-insertion of the shunt. Mild and transient worsening of preoperative symptoms was reported in these instances. No new postoperative neurological deficits were reported in the other 11 patients in whom INM data were preserved throughout surgery.

CONCLUSION

These data support routine use of INM in syringomyelia surgery. INM can alert the surgeon to potential intraoperative threats to the functional integrity of the spinal cord, providing a useful adjunct to spinal cord surgeries for the treatment of syringomyelia.

Magnetic resonance 4D flow analysis of cerebrospinal fluid dynamics in Chiari I malformation with and without syringomyelia

OBJECTIVE

To analyse cerebrospinal fluid (CSF) hydrodynamics in patients with Chiari type I malformation (CM) with and without syringomyelia using 4D magnetic resonance (MR) phase contrast (PC) flow imaging.

METHODS

4D-PC CSF flow data were acquired in 20 patients with CM (12 patients with presyrinx/syrinx). Characteristic 4D-CSF flow patterns were identified. Quantitative CSF flow parameters were assessed at the craniocervical junction and the cervical spinal canal and compared with healthy volunteers and between patients with and without syringomyelia.

RESULTS

Compared with healthy volunteers, 17 CM patients showed flow abnormalities at the craniocervical junction in the form of heterogeneous flow (n = 3), anterolateral flow jets (n = 14) and flow vortex formation (n = 5), most prevalent in patients with syringomyelia. Peak flow velocities at the craniocervical junction were significantly increased in patients (-15.5 ± 11.3 vs. -4.7 ± 0.7 cm/s in healthy volunteers, P < 0.001). At the level of C1, maximum systolic flow was found to be significantly later in the cardiac cycle in patients (30.8 ± 10.3 vs. 22.7 ± 4.1%, P < 0.05).

CONCLUSIONS

4D-PC flow imaging allowed comprehensive analysis of CSF flow in patients with Chiari I malformation. Alterations of CSF hydrodynamics were most pronounced in patients with syringomyelia.

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.

Decreased ratio of downward to horizontal smooth pursuit eye movement velocity in a patient with Chiari I malformation: application in early detection of vestibulocerebellar malfunction

A 72-year-old man presented with dizziness and left hand muscle atrophy. Magnetic resonance imaging revealed a spinal cord cavity and descent of the cerebellar tonsils. His diagnosis was Chiari I malformation with syringomyelia. No cerebellar signs were observed on physical examination. The cause of dizziness was investigated using a video-based eye movement tracker, which revealed a downward smooth pursuit velocity gain significantly below normal when expressed relative to the horizontal pursuit velocity gain. Vestibulocerebellar damage can cause mild downward pursuit deficit. The downward to horizontal smooth pursuit velocity gain ratio may be a more sensitive means of detecting vestibulocerebellar damage early.

Characterization of cyclic CSF flow in the foramen magnum and upper cervical spinal canal with MR flow imaging and computational fluid dynamics

CSF flow has been shown to exhibit complex patterns in MR images in both healthy subjects and in patients with Chiari I. Abnormal CSF flow oscillations, according to prevailing opinion, cause syringomyelia and other clinical manifestations that affect some patients with the Chiari I malformation. For this article, we reviewed the literature on PC MR of CSF flow, collected the published CFD studies relevant to CSF flow, and performed flow simulations. PC MR creates cine and still images of CSF flow and measurements of flow velocities. CFD, a technique used to compute flow and pressure in liquid systems, simulates the CSF flow patterns that occur in a specific geometry or anatomy of the SAS and a specific volume of flow. Published PC MR studies show greater peak CSF velocities and more complex flow patterns in patients with Chiari I than in healthy subjects, with synchronous bidirectional flow one of the characteristic markers of pathologic flow. In mathematic models of the SAS created from high-resolution MR images, CFD displays complex CSF flow patterns similar to those shown in PC MR in patients. CFD shows that the pressure and flow patterns vary from level to level in the upper spinal canal and differ between patients with Chiari and healthy volunteers. In models in which elasticity and motion are incorporated, CFD displays CSF pressure waves in the SAS. PC MR and CFD studies to date demonstrate significant alterations of CSF flow and pressure patterns in patients with Chiari I. CSF flow has nonlaminar complex spatial and temporal variations and associated pressure waves and pressure gradients. Additional simulations of CSF flow supplemented by PC MR will lead to better measures for distinguishing pathologic flow abnormalities that cause syringomyelia, headaches, and other clinical manifestations in Chiari I malformations.

Morphometric analysis of foramen magnum dimensions and intracranial volume in pediatric Chiari I malformation

PURPOSE

Foramen magnum dimensions and intracranial volume in Chiari I malformations in children were studied, and the statistical relationship between patient demographics, radiological features and foramen magnum morphometry was investigated.

METHODS

Linear measurements were used to calculate the intracranial volume using preoperative magnetic resonance images and computed tomogram images. The area of the foramen magnum was obtained independently using computer imaging software and a regression formula. The result of 21 pediatric patients was compared with a matched control group.

RESULTS

The area of the foramen magnum was within the range of the expected value deduced using a formula based on the intracranial volume. There was no statistical difference in the area and linear dimensions of the foramen magnum in the study and control groups. Six patients (28%) had a foramen magnum in close proximity to a spherical shape.

CONCLUSION

The authors provide a simple, accurate and reproducible method of estimating foramen magnum area in the pediatric Chiari I group. The irregular shape of the foramen magnum is accentuated by developmental bony and soft tissue anomalies at the cranio-vertebral junction in Chiari malformation. Consequently, an individualized cross-sectional assessment of the foramen magnum in relation to the hindbrain tissue in the same plane is required to study the initiation and propagation of the Chiari I symptomatology.

Decompression for Chiari type I-malformation (with or without syringomyelia) by extreme lateral foramen magnum opening and expansile duraplasty with arachnoid preservation: comparison with other technical modalities (Literature review)

Posterior craniocervical decompression is the procedure most currently used for treating Chiari I malformation (alone or in association with syringomyelia in the absence of hydrocephalus). We reviewed the various technical modalities reported in the literature. We present a personal series of 44 patients harboring Chiari type I malformation (CM-I) operated with a suboccipital craniectomy and a C1 (or C1/C2) laminectomy, plus an extreme lateral Foramen Magnum opening, a "Y" shaped dural incision with preservation of the arachnoid membrane, and an expansile duraplasty employing autogenous periosteum. Outcomes were analyzed with follow-up ranging from 1 to 10 years (4 years on average). The presented technique was compared with the other surgical modalities reported in the literature. This comparative study shows that this type of craniocervical decompression achieved the best results with minimal complications and side-effects. Syringomyelia associated with CM-I must be treated by craniocervical decompression alone. Shunting no longer appears to be an appropriate method of treatment for syringomyelia.

Electrophysiologic and clinical data support the use of dorsal root entry zone myelotomy in syringosubarachnoid shunting for syringomyelia

BACKGROUND

The objectives of this study were to correlate preoperative changes in SEPs with clinical sensory dysfunction and to establish their importance in planning the microsurgical approach, either by DM myelotomy or by DREZ myelotomy, for patients with syringomyelia.

METHODS

In addition to conducting clinical sensory examination, we evaluated the N13 potential after median nerve stimulation and CPs after tibial nerve stimulation intraoperatively before performing myelotomy on patients with syringomyelia (N = 14).

RESULTS

Eleven patients with intact DS presented with unilateral PTD, and 9 had distressing unilateral dermatomal pain. Deep sensibility was affected in 3 patients (bilaterally in 1 patient) without PTD. Patients with PTD were likely to have spontaneous pain (P = .005). A significant correlation between preoperative PTD and the absence of the N13 potential was demonstrated on the right (P = .015) and left (P = .004) sides. In patients with PTD, DREZ myelotomy on the symptomatic side is suggested as the treatment of choice, whereas DM myelotomy might be superior in patients without PTD.

CONCLUSIONS

Absence of pain or temperature sensation in patients with syringomyelia is usually accompanied by same-sided loss of the N13 potential, suggesting damage to the DH gray matter. Deep sensibility is typically normal, and DREZ myelotomy with preservation of DCs is proposed as the treatment of choice. Conducted potentials are usually distorted in patients with normal pain or temperature sensation and affected vibration and posture sensation, suggesting damage to DCs and making DM myelotomy the treatment of choice. Electrophysiologic and clinical data support the use of DREZ myelotomy in syringosubarachnoid shunting for syringomyelia in patients whose DCs have an intact function.

Tuberculous meningitis presenting as mesencephalic infarction and syringomyelia

Cerebral ischaemia is a serious complication of tuberculous meningitis (TBM) with the anterior circulation most commonly affected. Acute syringomyelia is a very rare complication of TBM. Here, we report an unusual presentation of TBM with a third nerve palsy as a result of posterior circulation stroke as well as a syringomyelia.

OBSERVATIONS ON SPINE DEFORMITY AND SYRINGOMYELIA

OBJECTIVE

Spine deformities, notably scoliosis, are known to occur in conjunction with syringomyelia. This study aims to analyze the effect of laminectomies performed in the course of treatment of syringomyelia. It examines the incidence, severity, and type of spine deformity as it relates to the extent and location of laminectomies performed.

METHODS

Records of 169 patients were analyzed for evidence of spinal deformity on imaging studies for the extent of the syringomyelic cavities and for previous surgical procedures on the spine. This analysis included patients with syringomyelia related to Chiari malformation, as well as patients with primary spinal pathology.

RESULTS

Spinal deformities were encountered in 41% of Chiari-syringomyelia patients who had not undergone previous surgery and in 57% of such patients who underwent reoperation. Scoliosis, the most common type of deformity encountered, was likely to be mild in patients who had not undergone previous surgery and severe in reoperated patients. Spine deformity was significantly more common in those patients who had more extensive bone removal.

CONCLUSION

Complete laminectomy should be avoided whenever possible in patients with syringomyelia because local denervation of the axial musculature, added to loss of medial anterior horn cells from syringomyelia, favors the development of spine deformities. This is particularly true of laminectomies performed at the junctional areas of the spine, i.e., cervical-thoracic and thoracolumbar. Hemilaminectomy usually suffices for shunt placement; instrumented stabilization should be considered in patients undergoing full laminectomy, especially those considered to be at high risk of developing deformity.

Atypical syringomyelia without cavity in a patient with Chiari malformation and hydrocephalus

STUDY DESIGN

A case report is presented.

OBJECTIVE

To investigate atypical syringomyelia without cavity.

SUMMARY OF BACKGROUND DATA

Syringomyelia without frank cavity is rarely reported. The MR imaging appearance of this atypical syringomyelia may help to understand the mechanism leading to the development of syringomyelia.

METHODS

Data are given for one patient who underwent MR imaging; she had Chiari malformation and hydrocephalus.

RESULTS

The patient had enlarged spinal cords, and gray matter T2 prolongation without cavitation occurred in association with continued cerebrospinal fluid obstruction in upper spine and improved after surgical intervention 14 days later.

CONCLUSION

Obstruction of the cerebrospinal fluid pathways in the upper spine may result in spinal cord gray matter T2 prolongation that is reversible after restoration of patency of cerebrospinal fluid pathways and stress the importance of timely intervention to limit progression to syringomyelia.

Chiari 1 malformation with syringomyelia: correlation of phase-contrast cine MR imaging and outcome

AIM

This study was designed to determine the hemodynamics of cerebrospinal fluid flow in syringomyelia patients associated with Chiari I malformation using phase-contrast velocity-encoded-cine MRI and also to find out whether treatment outcomes may be predicted by these flow measurements.

MATERIAL AND METHODS

Eighteen consecutive symptomatic patients with syringomyelia associated with Chiari 1 malformation were included. The PC VEC MRI was performed at the level of foramen magnum and syrinx cavity both preoperatively and 6 months postoperatively. Following surgery, the modified Asgari score was calculated, and the association between CSF flow pattern and clinical outcome was assessed.

RESULTS

Evaluation of clinical symptoms at postoperative 6th month revealed improvement in 11 (61%) patients and stabilization in 5 (28%) patients whereas results were poor in 2 (11%) patients. Preoperative cine MRI flow studies showed a heterogeneous pattern at the foramen magnum level in all of the patients. Postoperative cine MR flow studies demonstrated the change from heterogeneous pattern to sinusoidal pattern in 11 patients and a decrease in heterogeneity in 7 patients.

CONCLUSION

Our results indicate that CSF flow measurements using PC VEC MRI can give important information regarding the prognosis and follow-up of the patients with Chiari I malformation.

A detailed morphologic and functional magnetic resonance imaging study of the craniocervical junction in adolescent idiopathic scoliosis

STUDY DESIGN

Conventional and phase-contrast magnetic resonance (MR) imaging were used to evaluate the morphology and cerebrospinal fluid (CSF) flow dynamics at craniocervical junction in adolescent idiopathic scoliosis (AIS).

OBJECTIVES

To determine the morphology of cerebellar tonsil, foramen magnum, and dynamic flow of CSF at the craniocervical junction in AIS patients versus normal controls and their correlation with somatosensory cortical evoked potentials (SSEP).

SUMMARY OF BACKGROUND DATA

Previous studies have documented obstructed CSF flow in patients with Chiari I malformation. Low-lying cerebellar tonsils and syringomyelia are also observed in AIS patients. We sought to investigate whether disturbed CSF flow is also evident in AIS subjects at the foramen magnum level and its association with level of cerebellar tonsils and dimensions of foramen magnum.

METHODS

Conventional and phase-contrast MR were performed in 105 adolescent girls (69 AIS subjects and 36 age-matched controls). Measurements of cerebellar tonsillar level related to the basion-opsithion (BO) line, anteroposterior (AP), transverse (TS) diameter, and area of foramen magnum, and peak velocity of CSF flow in both the anterior and posterior subarachnoid space through foramen magnum were obtained. Correlations were made among different parameters and SSEP findings.

RESULTS

A total of 42% of subjects in the AIS group had the cerebellar tonsillar tip positioned 1 mm below the BO line. The cerebellar tonsillar level in AIS subjects was significantly lower than the median tonsillar level in normal controls (P < 0.01). The AP diameter and area of foramen magnum were significantly larger in AIS subjects when compared with normal controls (P < 0.05), but the peak CSF velocities through foramen magnum showed no significant difference (P > 0.05).

CONCLUSION

Peak CSF velocities through foramen magnum were not significantly different in AIS subjects despite the presence of low-lying cerebellar tonsils. This might be explained by the compensatory effect of larger foramen magnum in AIS subjects.

Abnormal sudomotor skin responses to temperature and pain stimuli in syringomyelia

Thermoalgesic sensory deficits in patients with syringomyelia may escape objective documentation with conventional electrophysiological techniques. We examined six patients with radiologically proven centrospinal cavities and patchy thermoalgesic sensory deficits by recording the evoked potentials and the sympathetic sudomotor skin responses (SSR) to laser stimuli. While electrical stimuli to the affected areas induced evoked potentials and SSRs of normal latency and amplitude, CO2 laser stimulation induced absent or abnormally reduced evoked potentials. Also, warmth and heat pain stimulation with a Peltier thermode induced absent or abnormal SSRs when applied over the affected areas but well defined SSRs when applied to the corresponding contralateral areas. Our results reveal the utility of recording the SSR to pain and temperature stimuli over specific body sites to demonstrate impairment of pain and temperature pathways in patients with syringomyelia. Comparison of electrical versus laser and temperature induced SSRs is an objective means to evaluate the selective thermoalgesic sensory deficit in these patients.

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.

Pseudoathetosis: report of three patients

We report on 3 patients with pseudoathetosis, which are involuntary, slow, writhing movements due to loss of proprioception.

Syringomyelia in infants secondary to mobile congenital atlantoaxial dislocation

We report a characteristic pattern of 'waist-like' syringomyelia observed in three infants having mobile and reducible congenital atlantoaxial dislocation. The syringomyelia in at least two of these cases was diagnosed to be an intramedullary tumor. Following atlantoaxial fixation, all three patients had long-term recovery of their symptoms.

[Pathogenesis of syringomyelia]

Formation of syringomyelic cavities may be caused by known pathologic processes, e.g. neoplastic tumours, arachnitis, traumas or malformations of the cranio-vertebral junction, while pathogenesis of idiopathic, primary syringomyelia has not been established so far. This paper presents a historic review of hypotheses and theories concerning the aetiology and pathophysiology of syringomyelia and their critical discussion. It points out the importance of communication between extracellular and subarachnoid spaces through the Virchov-Robin perivascular space. Disturbance of the outflow of extracellular fluid of the spinal cord may lead to dilatation of these canals and to formation of syringomyelic cavities because of raised volume of extracellular fluid.

Disproportionately Large Communicating Fourth Ventricle With Syringomyelia-Case Report-

A 13-year-old boy presented with syringomyelia associated with disproportionately large communicating fourth ventricle (DLCFV) manifesting as symptoms attributable to hydrocephalus and characteristic posterior fossa symptoms. Magnetic resonance imaging demonstrated remarkable dilation of the fourth ventricle and syringomyelia. Ventriculoperitoneal shunting completely resolved all symptoms as well as the ventricular and spinal cord abnormalities. Pre- and postoperative cine magnetic resonance imaging revealed the change of cerebrospinal fluid flow signal in the area of the foramen magnum. We concluded that the syringomyelia could be described as enlargement of the central canal with DLCFV.

Spontaneous resolution of syringomyelia and Chiari malformation Type I in a patient with cerebrospinal fluid otorrhea

✓ The spontaneous resolution of syringomyelia in the setting of a Chiari malformation Type I (CM-I) has been reported infrequently. Several theories about the pathogenesis and spontaneous resolution of syringomyelia associated with CM-I have been proposed. The authors present the case of a patient with spontaneous resolution of a CM-I and syringomyelia coinciding with the development of cerebrospinal fluid (CSF) otorrhea. Although cases of spontaneous resolution of syringomyelia have been reported, this is the first reported case of spontaneous resolution of syringomyelia and a CM-I associated with the simultaneous development of CSF otorrhea.

Evidence of familial syringomyelia in discordant association with Chiari type I malformation

We report a sister and two half brothers who presented with magnetic resonance imaging (MRI)-proven syringomyelia and associated Chiari type I malformation in two cases. The individuals have the same mother but two different fathers. The mother shows no clinical signs of syringomyelia. The two fathers died through unknown causes. In a third healthy son of the mother by a relationship with a third father syringomyelia was excluded by MRI. We believe that an autosomal-dominant predisposition is the primary factor in the appearance of syringomyelia in these cases.

Unraveling the riddle of syringomyelia

The pathophysiology of syringomyelia development is not fully understood. Current prevailing theories suggest that increased pulse pressure in the subarachnoid space forces cerebrospinal fluid (CSF) through the spinal cord into the syrinx. It is generally accepted that the syrinx consists of CSF. The here-proposed intramedullary pulse pressure theory instead suggests that syringomyelia is caused by increased pulse pressure in the spinal cord and that the syrinx consists of extracellular fluid. A new principle is introduced implying that the distending force in the production of syringomyelia is a relative increase in pulse pressure in the spinal cord compared to that in the nearby subarachnoid space. The formation of a syrinx then occurs by the accumulation of extracellular fluid in the distended cord. A previously unrecognized mechanism for syrinx formation, the Bernoulli theorem, is also described. The Bernoulli theorem or the Venturi effect states that the regional increase in fluid velocity in a narrowed flow channel decreases fluid pressure. In Chiari I malformations, the systolic CSF pulse pressure and downward motion of the cerebellar tonsils are significantly increased. This leads to increased spinal CSF velocities and, as a consequence of the Bernoulli theorem, decreased fluid pressure in narrow regions of the spinal CSF pathways. The resulting relatively low CSF pressure in the narrowed CSF pathway causes a suction effect on the spinal cord that distends the cord during each systole. Syringomyelia develops by the accumulation of extracellular fluid in the distended cord. In posttraumatic syringomyelia, the downwards directed systolic CSF pulse pressure is transmitted and reflected into the spinal cord below and above the traumatic subarachnoid blockage, respectively. The ensuing increase in intramedullary pulse pressure distends the spinal cord and causes syringomyelia on both sides of the blockage. The here-proposed concept has the potential to unravel the riddle of syringomyelia and affords explanations to previously unanswered clinical and theoretical problems with syringomyelia. It also explains why syringomyelia associated with Chiari I malformations may develop in any part of the spinal cord including the medullary conus. Syringomyelia thus preferentially develops where the systolic CSF flow causes a suction effect on the spinal cord, i.e., at or immediately caudal to physiological or pathological encroachments of the spinal subarachnoid space.

Segmental spinal myoclonus and syringomyelia: A case report

We report the case of a 75-year-old woman who developed involuntary jerks of the abdominal musculature. They occurred spontaneously or triggered by a forced inspiration or attempts to rise from the supine position. Electromyography (EMG) recorded abnormal bursts of muscle activity in the abdominal, thoracic paraspinal, and intercostal muscles up to the 3rd intercostal space. The bursts were bilateral, arrythmic and synchronous in all muscles. Magnetic resonance imaging (MRI) of the spine revealed a syringomyelic cavity between the T3 and T10 levels. The topological correlation between the EMG muscle activities and the MRI findings was consistent with spinal myoclonus arising from the thoracic spinal cord. The synchronous bursts in muscles depending from few adjacent spinal segments suggested the diagnosis of segmental spinal myoclonus (SSM). There are few reports of SSM related to syringomyelia in the literature.

Sleep-disordered breathing in patients with Chiari malformation: Improvement after surgery

Sixteen consecutive patients with Arnold-Chiari malformation type I and syringomyelia underwent full-night polysomnography (PSG). Sleep apnea syndrome (apnea-hypopnea index > 10) was diagnosed in 12 of 16 patients with 48% of central apneas. In six patients with sleep apnea syndrome, PSG was repeated an average of 203 days after decompression surgery. Postoperative PSG showed a decrease in the central apnea index from 14.9 +/- 5.5 to 1.3 +/- 0.6 (p = 0.03).

Radiologic presentations in relation to curve severity in scoliosis associated with syringomyelia

The purpose of the study was to further explore the radiological presentations of scoliosis associated with syringomyelia in relation to curve severity. 87 children and adolescents were divided into three groups: Group I (10 degrees <or=Cobb angle<or=30 degrees), Group II (30 degrees <Cobb angle<or=60 degrees), and Group III (Cobb angle >60 degrees). Curves were classified into typical and atypical patterns in the coronal plane and the sagittal profile measured. Cerebellar tonsillar descent or syrinx patterns in relation to curve severity and the frequency of atypical curves were also investigated. The frequency of atypical curve patterns from Group 1 to 2 was 46.2%, 45.2%, and 40.7% respectively. 65.3% patients with typical curve patterns had atypical features in all of the three groups. There was a significant difference of kyphotic angle among the three groups. Both the degree of cerebellar tonsillar descent and syrinx patterns had no correlation with the curve severity or the frequency of atypical curves. These results show that radiographic presentations, including atypical curve patterns, atypical features in typical curve patterns, and a normal to hyperkyphotic thoracic spine may suggest the need for preoperative MRI. There is no evidence to suggest that the degree of cerebellar tonsillar descent and syrinx patterns have an effect on the progress of scoliosis and the frequency of atypical curves.

Spontaneous regression of syringomyelia in Hajdu-Cheney syndrome with severe platybasia. Case report

Hadju-Cheney syndrome (HCS) is a rare autosomal-dominant disorder with variable expressivity. It is characterized by facial dysmorphism, premature tooth loss, osteolysis of distal phalanges, and skull abnormalities. In some cases, progressive platybasia can occur and can lead to Chiari malformation with an obstruction of cerebrospinal fluid flow. To the best of the authors' knowledge, only five cases of HCS-associated syringomyelia have been reported in the literature. Because of the rarity of this association, little is known about its natural history. The authors present the case of a 16-year-old boy affected by HCS. On initial magnetic resonance (MR) imaging, a severe basilar invagination with Chiari malformation and cervicothoracic syringomyelia was documented. The syringomyelia had no clinical manifestations. A repeated MR image demonstrated a spontaneous resolution of the syrinx with no changes in the tonsil or the platybasia. The regression of the syringomyelia was confirmed by a control MR imaging examination performed after a 2-year period. No changes in the patient's clinical conditions were found during the follow-up period. This is the first case of spontaneous regression of the syringomyelia despite a severe platybasia in HCS. It did not appear correlated to a modification of the tonsil's structure or position. This observation illustrates one possible evolution of syringomyelia in the natural history of HCS and raises the question of the potential mechanisms involved in the spontaneous drainage of the syringomyelic cavity.

Chiari malformation: CSF flow dynamics in the craniocervical junction and syrinx

BACKGROUND

A CSF flow study in patients with Chiari malformation (ChM) who undergo craniocervical junction decompression (CCJD).

METHODS

Using spatial modulation of magnetization (SPAMM), cerebrospinal fluid (CSF) flow velocities were measured at the prepontine (PP), anterior cervical (AC), and posterior cervical (PC) subarachnoid spaces (SAS) in healthy subjects (n = 11) and patients with Chiari malformation (ChM) before and/or after CCJD (n = 15). In the syringes, the intrasyrigeal pulsatile CSF motion was estimated qualitatively as present or absent.

FINDINGS

In normal subjects, the mean CSF velocities were 2.4 +/- 0.2 cm/s (PP), 2.8 +/- 0.3 cm/s (AC), and 2.4 +/- 0.2 cm/s (PC). Velocities were significantly lower than normal in patients with ChM prior to CCJD, reduced by 38%, 25%, and 79% in the 3 regions, respectively (P<0.001). Post-CCJD, velocities were 20% (PP), 100% (AC), and 40% (PC) greater than preoperatively (P<0.001).

CONCLUSIONS

In ChM, the posterior cervical CSF flow velocity was low, increased minimally after CCJD and, by itself, had limited predictive value. Post-CCJD, an increase of the sum of anterior and posterior cervical CSF flow velocities by more than 20% consistently preceded or coincided with marked headache improvement. After CCJD, the finding that the intrasyringeal CSF pulsatile motion had become absent was an earlier and more sensitive predictor of motor or sensory improvement than a reduction in syrinx's size. SPAMM can be used to assess whether CCJD has restored CSF flow, predict outcome and provide pathophysiological insights in ChM and syringomyelia.

Progressive syringomyelia controlled by treatment of associated hydrocephalus in an infant with birth injury

The author's aim in reporting this case is to extend awareness of the importance of management of associated hydrocephalus among patients with syringomyelia to the posttraumatic state. A full-term infant was delivered by cesarean section because of transverse lie. In the 2nd week of life, hypotonia affecting the lower limbs and the left upper limb was recognized. On MR imaging, posterior fossa subdural hemorrhage and spinal cord injury at the T-1 and T-2 levels were evident. Sequential imaging studies demonstrated progressive myelomalacic changes in the cervical spinal cord and eventual development of syrinx cavities as far cephalad as C-3. Hydrocephalus developed simultaneously as well. A ventriculoperitoneal cerebrospinal fluid shunt was inserted at 22 months of age. Six months after shunt insertion, MR imaging demonstrated regression of the posttraumatic syringomyelia. The patient was stable from an imaging standpoint at 16 months after shunt insertion, and she has continued to make developmental progress. The importance of treatment of associated hydrocephalus is widely recognized in the management of syringomyelia associated with the Chiari malformations. It should be considered in the management of posttraumatic syringomyelia as well.