The Pathogenesis of Syringomyelia: A Re-Evaluation of the Elastic-Jump Hypothesis

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
N. S. J. Elliott ◽  
D. A. Lockerby ◽  
A. R. Brodbelt
Keyword(s):  
Spinal Cord ◽  
Wave Propagation ◽  
Subarachnoid Space ◽  
Pressure Wave ◽  
Fluid Accumulation ◽  
Elastic Tubes ◽  
Spinal Subarachnoid Space ◽  
Poor Treatment ◽  
Relative Rarity ◽  
Set Up

Syringomyelia is a disease in which fluid-filled cavities, called syrinxes, form in the spinal cord causing progressive loss of sensory and motor functions. Invasive monitoring of pressure waves in the spinal subarachnoid space implicates a hydrodynamic origin. Poor treatment outcomes have led to myriad hypotheses for its pathogenesis, which unfortunately are often based on small numbers of patients due to the relative rarity of the disease. However, only recently have models begun to appear based on the principles of mechanics. One such model is the mathematically rigorous work of Carpenter and colleagues (2003, “Pressure Wave Propagation in Fluid-Filled Co-Axial Elastic Tubes Part 1: Basic Theory,” ASME J. Biomech. Eng., 125(6), pp. 852–856; 2003, “Pressure Wave Propagation in Fluid-Filled Co-Axial Elastic Tubes Part 2: Mechanisms for the Pathogenesis of Syringomyelia,” ASME J. Biomech. Eng., 125(6), pp. 857–863). They suggested that a pressure wave due to a cough or sneeze could form a shocklike elastic jump, which when incident at a stenosis, such as a hindbrain tonsil, would generate a transient region of high pressure within the spinal cord and lead to fluid accumulation. The salient physiological parameters of this model were reviewed from the literature and the assumptions and predictions re-evaluated from a mechanical standpoint. It was found that, while the spinal geometry does allow for elastic jumps to occur, their effects are likely to be weak and subsumed by the small amount of viscous damping present in the subarachnoid space. Furthermore, the polarity of the pressure differential set up by cough-type impulses opposes the tenets of the elastic-jump hypothesis. The analysis presented here does not support the elastic-jump hypothesis or any theory reliant on cough-based pressure impulses as a mechanism for the pathogenesis of syringomyelia.

Pressure Wave Propagation in Fluid-Filled Co-Axial Elastic Tubes Part 2: Mechanisms for the Pathogenesis of Syringomyelia

2003 ◽  
Vol 125 (6) ◽  
pp. 857-863 ◽  
Author(s):  
P. W. Carpenter ◽  
K. Berkouk ◽  
A. D. Lucey
Keyword(s):  
Spinal Cord ◽  
High Pressure ◽  
Cerebrospinal Fluid ◽  
Subarachnoid Space ◽  
Leading Edge ◽  
Propagation Mechanism ◽  
Fluid System ◽  
Elastic Tubes ◽  
Spinal Subarachnoid Space ◽  
Piston Mechanism

Our aim in this paper is to use a simple theoretical model of the intraspinal cerebrospinal-fluid system to investigate mechanisms proposed for the pathogenesis of syringomyelia. The model is based on an inviscid theory for the propagation of pressure waves in co-axial, fluid-filled, elastic tubes. According to this model, the leading edge of a pressure pulse tends to steepen and form an elastic jump, as it propagates up the intraspinal cerebrospinal-fluid system. We show that when an elastic jump is incident on a stenosis of the spinal subarachnoid space, it reflects to form a transient, localized region of high pressure within the spinal cord that for a cough-induced pulse is estimated to be 50 to 70 mm Hg or more above the normal level in the spinal subarachnoid space. We propose this as a new mechanism whereby pressure pulses created by coughing or sneezing can generate syrinxes. We also use the same analysis to investigate Williams’ suck mechanism. Our results do not support his concept, nor, in cases where the stenosis is severe, the differential-pressure-propagation mechanism recently proposed by Greitz et al. Our analysis does provide some support for the piston mechanism recently proposed by Oldfield et al. and Heiss et al. For instance, it shows clearly how the spinal cord is compressed by the formation of elastic jumps over part of the cardiac cycle. What appears to be absent for this piston mechanism is any means whereby the elastic jumps can be focused (e.g., by reflecting from a stenosis) to form a transient, localized region of high pressure within the spinal cord. Thus it would seem to offer a mechanism for syrinx progression, but not for its formation.

Temporal changes of spinal subarachnoid space patency after graded spinal cord injury in rats

Injury ◽  
2015 ◽  
Vol 46 (4) ◽  
pp. 634-637 ◽  
Author(s):  
Rebecca E. Franco-Bourland ◽  
Horacio J. Reyes-Alva ◽  
Alejandra Quintana-Armenta ◽  
Angelina Martinez-Cruz ◽  
Ignacio Madrazo ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Subarachnoid Space ◽  
Temporal Changes ◽  
Spinal Subarachnoid Space ◽  
Cord Injury

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.

Pathological basis of spinal cord cavitation in syringomyelia: analysis of 105 autopsy cases

1995 ◽  
Vol 82 (5) ◽  
pp. 802-812 ◽  
Author(s):  
Thomas H. Milhorat ◽  
Anthony L. Capocelli ◽  
Archinto P. Anzil ◽  
Rene M. Kotzen ◽  
Robert H. Milhorat
Keyword(s):  
Spinal Cord ◽  
Subarachnoid Space ◽  
Fourth Ventricle ◽  
Spastic Paraparesis ◽  
Central Canal ◽  
Spinal Cord Tissue ◽  
Content Type ◽  
Age Related ◽  
Spinal Subarachnoid Space ◽  
Fine Print

✓ This report summarizes neuropathological, clinical, and general autopsy findings in 105 individuals with nonneoplastic syringomyelia. On the basis of detailed histological findings, three types of cavities were distinguished: 1) dilations of the central canal that communicated directly with the fourth ventricle (47 cases); 2) noncommunicating (isolated) dilations of the central canal that arose below a syrinx-free segment of spinal cord (23 cases); and 3) extracanalicular syrinxes that originated in the spinal cord parenchyma and did not communicate with the central canal (35 cases). The incidence of communicating syrinxes in this study reflects an autopsy bias of morbid conditions such as severe birth defects. Communicating central canal syrinxes were found in association with hydrocephalus. The cavities were lined wholly or partially by ependyma and their overall length was influenced by age-related stenosis of the central canal. Noncommunicating central canal syrinxes arose at a variable distance below the fourth ventricle and were associated with disorders that presumably affect cerebrospinal fluid dynamics in the spinal subarachnoid space, such as the Chiari I malformation, basilar impression, and arachnoiditis. These cavities were usually defined rostrally and caudally by stenosis of the central canal and were much more likely than communicating syrinxes to dissect paracentrally into the parenchymal tissues. The paracentral dissections of the central canal syrinxes occurred preferentially into the posterolateral quadrant of the spinal cord. Extracanalicular (parenchymal) syrinxes were found typically in the watershed area of the spinal cord and were associated with conditions that injure spinal cord tissue (for example, trauma, infarction, and hemorrhage). A distinguishing feature of this type of cavitation was its frequent association with myelomalacia. Extracanalicular syrinxes and the paracentral dissections of central canal syrinxes were lined by glial or fibroglial tissue, ruptured frequently into the spinal subarachnoid space, and were characterized by the presence of central chromatolysis, neuronophagia, and Wallerian degeneration. Some lesions extended rostrally into the medulla or pons (syringobulbia). Although clinical information was incomplete, simple dilations of the central canal tended to produce nonspecific neurological findings such as spastic paraparesis, whereas deficits associated with extracanalicular syrinxes and the paracentral dissections of central canal syrinxes included segmental signs that were referable to affected nuclei and tracts. It is concluded that syringomyelia has several distinct cavitary patterns with different mechanisms of pathogenesis that probably determine the clinical features of the condition.

Robot-assisted endoscopic exploration of the spinal cord

2010 ◽  
Vol 224 (7) ◽  
pp. 1515-1529 ◽  
Author(s):  
L Ascari ◽  
C Stefanini ◽  
U Bertocchi ◽  
P Dario
Keyword(s):  
Spinal Cord ◽  
Subarachnoid Space ◽  
Ex Vivo ◽  
Hierarchical Control ◽  
Three Dimensional ◽  
Robot Assisted ◽  
Actuation System ◽  
Spinal Subarachnoid Space

This work presents the design and development of an integrated image-guided robot-assisted endoscopic system for the safe navigation within the spinal subarachnoid space, providing the surgeon with the direct vision of the structures (i.e. spinal cord, roots, vessels) and the possibility of performing some particularly useful operations, like local electrostimulation of nerve roots. The modelling, micro-fabrication, fluidic sustentation, and cable-based actuation system of a steerable tip for a multilumen flexible catheter is described; the hierarchical control system shared between the surgeon and the computer, and based on machine vision techniques and a simple but effective three-dimensional reconstruction is detailed. The Blind Expected Perception sensory-motor scheme is proposed in robot-assited endoscopy. Results from in vitro, ex vivo, and in vivo experiments show that the described model can accurately predict the shape of the catheter given the tension distribution on the cables, that the proposed actuation system can assure smooth and precise control of the catheter tip, that the fluidic sustentation of the catheter is essential in in vivo navigation, and that the proposed rear view mirror interface to show non-visible obstacles is appropriate; in conclusion, the results proved the validity of the proposed solution to develop an intrinsically safe robotic system for navigation and intervention in a narrow and challenging environment such as the spinal subarachnoid space.

Syrinx Fluid Transport: Modeling Pressure-Wave-Induced Flux Across the Spinal Pial Membrane

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
N. S. J. Elliott
Keyword(s):  
Spinal Cord ◽  
Wave Propagation ◽  
Spinal Canal ◽  
Pressure Wave ◽  
Elastic Tube ◽  
Analytical Models ◽  
Perivascular Spaces ◽  
Interstitial Flow ◽  
Fluid Exchange ◽  
Wave Induced

Syrinxes are fluid-filled cavities of the spinal cord that characterize syringomyelia, a disease involving neurological damage. Their formation and expansion is poorly understood, which has hindered successful treatment. Syrinx cavities are hydraulically connected with the spinal subarachnoid space (SSS) enveloping the spinal cord via the cord interstitium and the network of perivascular spaces (PVSs), which surround blood vessels penetrating the pial membrane that is adherent to the cord surface. Since the spinal canal supports pressure wave propagation, it has been hypothesized that wave-induced fluid exchange across the pial membrane may play a role in syrinx filling. To investigate this conjecture a pair of one-dimensional (1-d) analytical models were developed from classical elastic tube theory coupled with Darcy’s law for either perivascular or interstitial flow. The results show that transpial flux serves as a mechanism for damping pressure waves by alleviating hoop stress in the pial membrane. The timescale ratio over which viscous and inertial forces compete was explicitly determined, which predicts that dilated PVS, SSS flow obstructions, and a stiffer and thicker pial membrane—all associated with syringomyelia—will increase transpial flux and retard wave travel. It was also revealed that the propagation of a pressure wave is aided by a less-permeable pial membrane and, in contrast, by a more-permeable spinal cord. This is the first modeling of the spinal canal to include both pressure-wave propagation along the spinal axis and a pathway for fluid to enter and leave the cord, which provides an analytical foundation from which to approach the full poroelastic problem.

Damping Effect on Mechanical Waves in an Elastic Solid Expanded Tubular

2006 ◽  
Vol 129 (4) ◽  
pp. 698-712
Author(s):  
A. Karrech ◽  
A. Seibi ◽  
T. Pervez
Keyword(s):  
Mathematical Model ◽  
Wave Propagation ◽  
Pressure Wave ◽  
Elastic Solid ◽  
Tube System ◽  
Structure Interaction ◽  
Damping Effect ◽  
Elastic Tubes ◽  
Mechanical Waves ◽  
Critical Regions

The present paper studies the dynamics of submerged expanded elastic tubes due to postexpansion sudden mandrel release known as pop-out phenomenon. A mathematical model describing the dynamics of the borehole-fluid-tube system is presented. Coupling of the fluid-structure interaction and damping effects were taken into consideration. An analytical solution for the displacement, stress, and pressure wave propagation in the fluid-tube system was obtained. The developed model predicted localized critical regions where the structure might experience failure.

The spinal cord central canal in kaolin-induced hydrocephalus

1977 ◽  
Vol 47 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Ansgar Torvik ◽  
V. S. Murthy
Keyword(s):  
Spinal Cord ◽  
Subarachnoid Space ◽  
Fourth Ventricle ◽  
Central Canal ◽  
Content Type ◽  
Spinal Subarachnoid Space ◽  
Individual Variations ◽  
Lower Brain Stem ◽  
Cleft Formation ◽  
Fine Print

✓ In order to study the cause of the great individual variations in kaolin-induced hydrocephalus, the lower brain stem and upper spinal cord were examined histologically in a series of young rabbits that had received injections of kaolin into the cisterna magna. Animals with complete occlusion of the outlets from the fourth ventricle into the subarachnoid space showed only a moderate ventricular dilatation, while cases with marked hydrocephalus also had plugs of kaolin in the caudal part of the fourth ventricle. The intraventricular kaolin was adherent to the roof of the fourth ventricle by strands of connective tissue and it is suggested that the plugs served as valves that initially occluded the opening of the central canal and were then lifted away as the ventricle dilated and the roof moved posteriorly. The animals with marked hydrocephalus also had extensive dilatation of the central canal with cleft formation in the posterior columns. The observations support the concept that in hydrocephalus the central canal may serve as an alternative resorption route for the cerebrospinal fluid through communication with the spinal subarachnoid space.

scholarly journals Cerebrospinal fluid drainage kinetics across the cribriform plate are reduced with aging

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Molly Brady ◽  
Akib Rahman ◽  
Abigail Combs ◽  
Chethana Venkatraman ◽  
R. Tristan Kasper ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cerebrospinal Fluid ◽  
Subarachnoid Space ◽  
Ex Vivo ◽  
Cribriform Plate ◽  
Cervical Lymph Nodes ◽  
Spinal Subarachnoid Space ◽  
Ex Vivo Tissues ◽  
The Brain

Abstract Background Continuous circulation and drainage of cerebrospinal fluid (CSF) are essential for the elimination of CSF-borne metabolic products and neuronal function. While multiple CSF drainage pathways have been identified, the significance of each to normal drainage and whether there are differential changes at CSF outflow regions in the aging brain are unclear. Methods Dynamic in vivo imaging of near infrared fluorescently-labeled albumin was used to simultaneously visualize the flow of CSF at outflow regions on the dorsal side (transcranial and -spinal) of the central nervous system. This was followed by kinetic analysis, which included the elimination rate constants for these regions. In addition, tracer distribution in ex vivo tissues were assessed, including the nasal/cribriform region, dorsal and ventral surfaces of the brain, spinal cord, cranial dura, skull base, optic and trigeminal nerves and cervical lymph nodes. Results Based on the in vivo data, there was evidence of CSF elimination, as determined by the rate of clearance, from the nasal route across the cribriform plate and spinal subarachnoid space, but not from the dorsal dural regions. Using ex vivo tissue samples, the presence of tracer was confirmed in the cribriform area and olfactory regions, around pial blood vessels, spinal subarachnoid space, spinal cord and cervical lymph nodes but not for the dorsal dura, skull base or the other cranial nerves. Also, ex vivo tissues showed retention of tracer along brain fissures and regions associated with cisterns on the brain surfaces, but not in the brain parenchyma. Aging reduced CSF elimination across the cribriform plate but not that from the spinal SAS nor retention on the brain surfaces. Conclusions Collectively, these data show that the main CSF outflow sites were the nasal region across the cribriform plate and from the spinal regions in mice. In young adult mice, the contribution of the nasal and cribriform route to outflow was much higher than from the spinal regions. In older mice, the contribution of the nasal route to CSF outflow was reduced significantly but not for the spinal routes. This kinetic approach may have significance in determining early changes in CSF drainage in neurological disorder, age-related cognitive decline and brain diseases.

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