Evaluation by Fluid/Structure-Interaction Spinal-Cord Simulation of the Effects of Subarachnoid-Space Stenosis on an Adjacent Syrinx

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
C. D. Bertram
Keyword(s):  
Spinal Cord ◽  
Dura Mater ◽  
Subarachnoid Space ◽  
Short Pulse ◽  
Fluid Motion ◽  
Pulse Excitation ◽  
Longitudinal Motion ◽  
Pia Mater ◽  
Bulk Fluid ◽  
Fluid Displacement

A finite-element numerical model was constructed of the spinal cord, pia mater, filum terminale, cerebrospinal fluid in the spinal subarachnoid space (SSS), and dura mater. The cord was hollowed out by a thoracic syrinx of length 140 mm, and the SSS included a stenosis of length 30 mm opposite this syrinx. The stenosis severity was varied from 0% to 90% by area. Pressure pulse excitation was applied to the model either at the cranial end of the SSS, simulating the effect of cranial arterial pulsation, or externally to the abdominal dura mater, simulating the effect of cough. A very short pulse was used to examine wave propagation; a pulse emulating cardiac systole was used to examine the effects of fluid displacement. Additionally, repetitive sinusoidal excitation was applied cranially. Bulk fluid flow past the stenosis gave rise to prominent longitudinal pressure dissociation (“suck”) in the SSS adjacent to the syrinx. However, this did not proportionally increase the longitudinal motion of fluid in the syrinx. The inertia of the fluid in the SSS, together with the compliance of this space, gave a resonance capable of being excited constructively or destructively by cardiac or coughing impulses. The main effect of mild stenosis was to lower the frequency of this resonance; severe stenosis damped out to-and-fro motions after the end of the applied excitation. Syrinx fluid motion indicated the fluid momentum and thus the pressure developed when the fluid was stopped by the end of the syrinx; however, the tearing stress in the local cord material depended also on the instantaneous local SSS pressure and was therefore not well predicted by syrinx fluid motion. Stenosis was also shown to give rise to a one-way valve effect causing raised SSS pressure caudally and slight average cord displacement cranially. The investigation showed that previous qualitative predictions of the effects of suck neglected factors that reduced the extent of the resulting syrinx fluid motion and of the cord tearing stress, which ultimately determines whether the syrinx lengthens.

Professor Betz's Method of Making Sections of Nervous Tissue

1873 ◽  
Vol 19 (87) ◽  
pp. 465-466
Author(s):  
Batty Tuke
Keyword(s):  
Spinal Cord ◽  
Dura Mater ◽  
Nervous Tissue ◽  
Cool Temperature ◽  
Cent Solution ◽  
Pia Mater ◽  
Thin Sections ◽  
Brown Colour ◽  
Ordinary Temperature

Professor Betz, of Kiew, has lately produced brain sections, which have attracted very considerable attention in Vienna. His specimens are of vast extent. He appears to be able to produce thin sections of an entire hemisphere. We append his method of hardening and cutting as it is stated in the “Correspondentze Blatt der deutschen Gesellschaft für Psychiatrie und Gerichtlich Psychologie, Jan., 1873.” The method of hardening which we wish to bring into notice is as follows:—observing that differences exist in the treatment of the spinal-cord, cerebrum and cerebellum. The spinal-cord—after tbe careful removal of the dura mater, it is placed in spirit of from 75 to 80 per cent., which is tinged a clear brown colour by the addition of Iodine. After from one to three days, during which the preparation must stand in a cool temperature, the Pia Mater and the Arachnoid are also removed; the specimen remaining in the spirit, to which a few drops of Iodine must be added daily for three days, maintaining an ordinary temperature. It is then transferred to a three per cent. solution of Chromate of Potass, and back again to the cool temperature. Here it hardens thoroughly, which is known by the fluid becoming turbid, and by the formation of a brown deposit upon the preparation. When this occurs, it must be immediately thoroughly washed with water, and immersed in a solution of Chromate of Potass, from a half to one per cent. strength, in which it will not become too hard or brittle.

Surgical treatment of the retethered spinal cord after repair of lipomyelomeningocele

1991 ◽  
Vol 74 (5) ◽  
pp. 709-714 ◽  
Author(s):  
Hiroaki Sakamoto ◽  
Akira Hakuba ◽  
Ken Fujitani ◽  
Shuro Nishimura
Keyword(s):  
Spinal Cord ◽  
Dura Mater ◽  
Conus Medullaris ◽  
Posterior Arch ◽  
Pia Mater ◽  
Dense Adhesion ◽  
Content Type ◽  
Dural Sac ◽  
Long Term Observation

✓ In a series of 75 patients with surgically treated lipomyelomeningoceles, the neurological condition of six patients deteriorated 6 months to 14 years after the operation due to repeat tethering of the spinal cord. The tethering resulted from postoperative dense adhesion between the cord and the overlying dura mater. Two of the six patients underwent conventional repeat untethering procedures, and the remaining four were successfully treated with a new surgical technique developed by the authors to prevent such dural adhesion. For this procedure, after complete untethering of the spinal cord, the lumbosacral cord is retained in the center of the dural sac by fine stay sutures between the pia mater of the conus medullaris and the ventral dura mater. In addition, the dura mater is tacked to the posterior arch which is reconstructed with bone grafts at one or two bifid vertebral levels. During a postoperative follow-up period of 1 to 3 years, no further deterioration has been observed and magnetic resonance studies have demonstrated a space filled with cerebrospinal fluid (CSF) around the lumbosacral cord. The authors conclude that long-term observation, both neurological and radiological, is essential even after successful repair of a lipomyelomeningocele. This new surgical procedure can maintain a CSF bath around the lumbosacral cord, thus preventing dural adhesion. Application of this technique will hopefully be beneficial in lipomyelomeningocele patients with a high risk of cord retethering after initial repair.

Dorsal arachnoid web with spinal cord compression: variant of an arachnoid cyst?

2000 ◽  
Vol 93 (2) ◽  
pp. 287-290 ◽  
Author(s):  
Christopher G. Paramore
Keyword(s):  
Spinal Cord ◽  
Subarachnoid Space ◽  
Rare Variants ◽  
Mass Effect ◽  
Arachnoid Cysts ◽  
Thoracic Myelopathy ◽  
Pia Mater ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal

✓ Spinal arachnoid cysts are diverticula of the subarachnoid space that may compress the spinal cord; these lesions are most commonly found in the thoracic spine. Two patients who presented with thoracic myelopathy were noted on magnetic resonance imaging to have focal indentation of the dorsal thoracic cord, with syringomyelia inferior to the site of compression. Both patients were found at operation to have discrete arachnoid “webs” tenaciously attached to the dura mater and pia mater. These webs were not true arachnoid cysts, yet they blocked the flow of cerebrospinal fluid (CSF) and caused focal compression of the spinal cord. The mass effect appeared to be the result of a pressure gradient created by the obstruction of CSF flow in the dorsal aspect of the subarachnoid space. Both patients responded well to resection of the arachnoid web. Arachnoid webs appear to be rare variants of arachnoid cysts and should be suspected in patients with focal compression of the thoracic spinal cord.

scholarly journals Clinical and Histological Effects of the Intrathecal Administration of a Single Dose of Dexmedetomidine in Rabbits

2016 ◽  
Vol 19 (2;2) ◽  
pp. E319-E327 ◽  
Author(s):  
Eliana Marisa Ganem
Keyword(s):  
Spinal Cord ◽  
Single Dose ◽  
Subarachnoid Space ◽  
Design Research ◽  
Control Group ◽  
Epidural Administration ◽  
Pia Mater ◽  
Neuroprotective Effects ◽  
Histological Changes ◽  
Preservative Free

Background: There is experimental evidence that dexmedetomidine has neuroprotective effects. So, it could be expected that its intrathecal or epidural administration presents no harm. However, whether dexmedetomidine is neurotoxic to the spinal cord remains to be fully elucidated. Objective: To evaluate the effect of preservative-free dexmedetomidine administered as a subarachnoid single injection on the spinal cord and meninges of rabbits. Study Design: Research article. Setting: Experimental research laboratory. Methods: Twenty young adult female rabbits, each weighing between 3200 and 4900 g, and having a spine length between 36 and 40 cm, were divided by lot into 2 groups (G): 0.9% saline in G1 and preservative-free dexmedetomidine in G2 (dose of 10 μg). After intravenous anesthesia with ketamine and xylazine, the subarachnoid space was punctured at S1-S2 under ultrasound guidance, and a random 5 µl.cm-1 of spinal length (0.2 mL) of solution (saline or dexmedetomidine) was injected. The animals remained in captivity for 21 days under medical observation and were sacrificed by decapitation. The lumbosacral spinal cord portion was removed for immunohistochemistry to assess the glial fibrillary acidic protein (GFAP), and histology was assessed using hematoxylin and eosin (HE) stain. Results: None of the animals had impaired motor function or decreased nociception during the period of clinical observation. None of the animals from the control group showed signs of injuries to meninges. In the dexmedetomidine group, however, 9 animals presented with signs of meningeal injury. The main histological changes observed were areas with meningeal thickening and lymphoplasmocitary infiltration in the pia-mater and arachnoid. Further histological examination also revealed adherence areas among the pia and arachnoid. There was no signal of injury in neural tissue in any animal of both groups. Limitations: Evaluation of the possible analgesic effects of the intrathecal dexmedetomidine was not performed. Conclusion: On the basis of the present results, dexmedetomidine administered in the subarachnoid space in a single dose of 10 µg is capable of producing histological changes over the meninges of rabbits. Key Words: Anesthesia, spinal; dexmedetomine; injections, spinal; spinal cord; rabbits

Professor Betz's Method of Making Sections of Nervous Tissue

1873 ◽  
Vol 19 (87) ◽  
pp. 465-466
Author(s):  
Batty Tuke
Keyword(s):  
Spinal Cord ◽  
Dura Mater ◽  
Nervous Tissue ◽  
Cool Temperature ◽  
Cent Solution ◽  
Pia Mater ◽  
Thin Sections ◽  
Brown Colour ◽  
Ordinary Temperature

Professor Betz, of Kiew, has lately produced brain sections, which have attracted very considerable attention in Vienna. His specimens are of vast extent. He appears to be able to produce thin sections of an entire hemisphere. We append his method of hardening and cutting as it is stated in the “Correspondentze Blatt der deutschen Gesellschaft für Psychiatrie und Gerichtlich Psychologie, Jan., 1873.” The method of hardening which we wish to bring into notice is as follows:—observing that differences exist in the treatment of the spinal-cord, cerebrum and cerebellum. The spinal-cord—after tbe careful removal of the dura mater, it is placed in spirit of from 75 to 80 per cent., which is tinged a clear brown colour by the addition of Iodine. After from one to three days, during which the preparation must stand in a cool temperature, the Pia Mater and the Arachnoid are also removed; the specimen remaining in the spirit, to which a few drops of Iodine must be added daily for three days, maintaining an ordinary temperature. It is then transferred to a three per cent. solution of Chromate of Potass, and back again to the cool temperature. Here it hardens thoroughly, which is known by the fluid becoming turbid, and by the formation of a brown deposit upon the preparation. When this occurs, it must be immediately thoroughly washed with water, and immersed in a solution of Chromate of Potass, from a half to one per cent. strength, in which it will not become too hard or brittle.

Intraspinal mesenchymal chondrosarcoma

1994 ◽  
Vol 80 (5) ◽  
pp. 928-930 ◽  
Author(s):  
Alok Ranjan ◽  
Geeta Chacko ◽  
Thomas Joseph ◽  
Sushil M. Chandi
Keyword(s):  
Spinal Cord ◽  
Magnetic Resonance ◽  
Dura Mater ◽  
Microscopic Examination ◽  
Mesenchymal Chondrosarcoma ◽  
Pia Mater ◽  
Content Type ◽  
The Right ◽  
Fine Print

✓ A 52-year-old man presented with symptoms of progressive cervical radiculomyelopathy. A myelogram showed an intradural block at the C-6 level. Magnetic resonance T1-weighted imaging revealed a hypointense, sausage-shaped mass extending from C-3 to C-6, located posterolaterally on the right side and pushing the spinal cord to the left and anteriorly. At surgery, a mass was found attached solely to the pia mater, with a normal arachnoid and dura mater overlying it. The mass was excised completely and microscopic examination identified a mesenchymal chondrosarcoma. The patient was symptom-free 6 months after surgery.

Postoperative fibrosis after surgical treatment of the porcine spinal cord: a comparison of dural substitutes

2005 ◽  
Vol 2 (1) ◽  
pp. 50-54 ◽  
Author(s):  
Iftikharul Haq ◽  
Yenisel Cruz-Almeida ◽  
Edir B. Siqueira ◽  
Michael Norenberg ◽  
Barth A. Green ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Adverse Effects ◽  
Subarachnoid Space ◽  
Histological Evaluation ◽  
Postoperative Adhesion ◽  
Pia Mater ◽  
Content Type ◽  
Inflammatory Reactions ◽  
Dural Substitute ◽  
Fine Print

Object. Postoperative adhesion- and fibrosis-induced spinal cord tethering is not uncommon and may be associated with delayed clinical sequelae. Multiple dural substitutes have been used in surgery without a full appreciation of the grafts' adverse effects. The authors conducted a comparative animal experimental study to evaluate the degree of chronic inflammatory reactions, adhesions, and fibrosis caused by the use of four dural substitutes—Surgicel, Durasis, DuraGen, and Preclude. Methods. Twenty-six pigs weighing 30 to 40 kg underwent a two-level lumbar laminectomy (a midline durotomy, implantation of a 2-cm dural substitute in the subarachnoid space, and watertight dural closure). After 8 weeks the animals were killed, and two independent neuropathologists blinded to the dural substitute group evaluated several sites along the implants, providing descriptions and quantitative scoring of fibrosis, chronic inflammatory reactions, foreign-body reactions, and spinal cord changes. Kruskal—Wallis one-way analysis of variance for ranks corrected for multiple comparisons was used to examine differences among the materials. Conclusions. The DuraGen dural substitute produced the least amount of inflammation in the subarachnoid space and Preclude generated the most (p < 0.001). Surgicel and DuraGen were completely resorbed on histological sections, but both produced some inflammation, which diminished gradually from the dural implant center. Histological evaluation of the nonresorbed grafts demonstrated that Durasis caused the least degree of inflammatory cell infiltration (p < 0.001). The Preclude dural substitute consistently demonstrated encapsulation and arachnoidal reaction. There was no evidence of implant-related adverse effects on the underlying pia mater and white matter regardless of the substitute type.

On the Trabecular Morphologies and Load Transfer to the Brain

2013 ◽  
Author(s):  
Siavash Hashemi ◽  
Parisa Saboori ◽  
Shahab Mansoor-Baghaei ◽  
Ali M. Sadegh
Keyword(s):  
Human Brain ◽  
Dura Mater ◽  
Subarachnoid Space ◽  
Load Transfer ◽  
Trabecular Architecture ◽  
Pia Mater ◽  
Tree Shape ◽  
External Loads ◽  
The Brain ◽  
Arachnoid Mater

The human brain trabeculae contain strands of collagen tissues connecting the arachnoid to the pia mater. In this paper the mechanotransductions of the external loads to the head passing through different trabecular architectures of the subarachnoid space were investigated. This has been accomplished by creating several local 2-D models consist of skull, dura mater, arachnoid, trabecular architecture and the brain. Different orientations of several architectures of the trabeculae were also analyzed. All models were subjected to the same loading and constraints. The strains in the brain for each model of the architecture and morphology were determined and compared to other corresponding models. It is concluded that the strain in the brain is less where the tree-shape trabeculae are upright, where the branches are attached to the arachnoid mater and the stems are attached to the pia mater. In addition, in the case of other morphologies the strain in the brain is less when the ratio of the trabecular area to the CSF space is less.

scholarly journals In vivo assessment of spinal cord elasticity using shear wave ultrasound in dogs

2018 ◽  
Vol 29 (4) ◽  
pp. 461-469 ◽  
Author(s):  
Amro Al-Habib ◽  
Abdulrahman Albakr ◽  
Abdullah Al Towim ◽  
Metab Alkubeyyer ◽  
Abdullah Abu Jamea ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Shear Wave ◽  
Dura Mater ◽  
Ex Vivo ◽  
Shear Wave Elastography ◽  
Biomechanical Properties ◽  
Tissue Elasticity ◽  
Pia Mater ◽  
Balloon Compression

OBJECTIVEEvaluation of living tissue elasticity has wide applications in disease characterization and prognosis prediction. Few previous ex vivo attempts have been made to characterize spinal cord elasticity (SCE). Recently, tissue elasticity assessment has been clinically feasible using ultrasound shear wave elastography (SWE). The current study aims to characterize SCE in healthy dogs, in vivo, utilizing SWE, and to address SCE changes during compression.METHODSTen Greyhound dogs (mean age 14 months; mean weight 14.3 kg) were anesthetized and tracheally intubated, with hemodynamic and neurological monitoring. A 3-level, midcervical laminectomy was performed. SCE was assessed at baseline. Next, 8- and 13-mm balloon compressions were sequentially applied ventral to the spinal cord.RESULTSThe mean SCE was 18.5 ± 7 kPa. Elasticity of the central canal, pia mater, and dura mater were 21.7 ± 9.6 kPa, 26.1 ± 14.8 kPa, and 63.2 ± 11.5 kPa, respectively. As expected, the spinal cord demonstrated less elasticity than the dura mater (p < 0.0001) and pia mater (trend toward significance p = 0.08). Notably, the 13-mm balloon compression resulted in a stiffer spinal cord than at baseline (233 ± 73 kPa versus 18.5 ± 7 kPa, p < 0.0001) and 8-mm balloon compression (233 ± 73 kPa versus 185 ± 68 kPa, p < 0.048).CONCLUSIONSIn vivo SCE evaluation using SWE is feasible and comparable to earlier reports, as demonstrated by physical sectioning of the spinal cord. The compressed spinal cord is stiffer than a free spinal cord, with a linear increase in SCE with increasing mechanical compression. Knowledge of the biomechanical properties of the spinal cord including SCE has potential implications for disease management and prognosis.

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