Biomechanics of the Spinal Cord and the Pia Mater

Author(s):  
Hiroshi Ozawa ◽  
Takeo Matsumoto ◽  
Toshiro Ohashi ◽  
Masaaki Sato
Keyword(s):  
1873 ◽  
Vol 19 (87) ◽  
pp. 465-466
Author(s):  
Batty Tuke

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.


1991 ◽  
Vol 74 (5) ◽  
pp. 709-714 ◽  
Author(s):  
Hiroaki Sakamoto ◽  
Akira Hakuba ◽  
Ken Fujitani ◽  
Shuro Nishimura

✓ 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.


1988 ◽  
Vol 69 (2) ◽  
pp. 276-282 ◽  
Author(s):  
David S. Nicholas ◽  
Roy O. Weller

✓ The fine anatomy of the human spinal meninges was examined in five postmortem spinal cords taken within 12 hours after death from patients aged 15 months to 46 years. Specimens of spinal cord were viewed in transverse section and from the dorsal and ventral aspects by scanning electron microscopy. Transverse sections of spinal cord and meninges were also examined by light microscopy. The arachnoid mater was seen to be closely applied to the inner aspect of the dura. An intermediate fenestrated leptomeningeal layer was observed attached to the inner aspect of the arachnoid mater and was reflected ventrally to form a series of dorsal septa. As it arborized laterally over the surface of the cord to surround nerves and blood vessels, the intermediate layer became highly fenestrated but remained distinct from the pia and arachnoid mater. The pia mater appeared to form a continuous layer which was reflected off the surface of the cord to coat blood vessels within the subarachnoid space in a manner similar to that described in the leptomeninges over the human cerebral cortex. Each dentate ligament consisted of a collagenous core which was continuous with the subpial connective tissue and was attached at intervals to the dura; pia-arachnoid cells coated the surface of the dentate ligaments. The present study suggests that the fine anatomy of the human spinal meninges differs significantly from that described in other mammals.


2019 ◽  
Vol 18 (1) ◽  
pp. E3-E4
Author(s):  
Benjamin K Hendricks ◽  
Robert F Spetzler

Abstract Symptomatic spinal arteriovenous malformations (AVMs) are most frequently associated with hypoperfusion of the spinal cord, either from venous congestion or vascular steal, and are less frequently associated with hemorrhage. This patient had a large cervicothoracic spinal AVM and presented with right hemibody sensory deficit with intact motor function. The AVM had significant preoperative mass effect on the dorsal spinal cord with cord signal change. Preoperative digital subtraction angiography demonstrated a left supreme intercostal feeding artery and left thyrocervical feeding artery, which was embolized preoperatively. A laminoplasty was performed from cervical 7 to thoracic 3 to allow for adequate visualization. The lesion demonstrated an intradural extramedullary presence, which made preservation of the pia mater paramount during the resection. The AVM was disconnected and removed in its entirety as determined by operative visualization and postoperative imaging. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.


Spine ◽  
2016 ◽  
Vol 41 (9) ◽  
pp. E524-E529 ◽  
Author(s):  
Daniel M. Harwell ◽  
Justin L. Gibson ◽  
Richard David Fessler ◽  
Jeffrey Holtz ◽  
David B. Pettigrew ◽  
...  

2000 ◽  
Vol 93 (2) ◽  
pp. 287-290 ◽  
Author(s):  
Christopher G. Paramore

✓ 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.


2010 ◽  
Vol 12 (3) ◽  
pp. 301-305 ◽  
Author(s):  
Yoshihiko Kato ◽  
Tsukasa Kanchiku ◽  
Yasuaki Imajo ◽  
Kotaro Kimura ◽  
Kazuhiko Ichihara ◽  
...  

Object The authors evaluated the biomechanical effect of 3 different degrees of static compression in a model of the spinal cord in order to investigate the effect of cord compression in patients with ossification of the posterior longitudinal ligament (OPLL). Methods A 3D finite element spinal cord model consisting of gray matter, white matter, and pia mater was established. As a simulation of OPLL-induced compression, a rigid plate compressed the anterior surface of the cord. The degrees of compression were 10, 20, and 40% of the anteroposterior (AP) diameter of the cord. The cord was supported from behind by the rigid body along its the posterior border, simulating the lamina. Stress distributions inside of the cord were evaluated. Results The stresses on the cord were very low under 10% compression. At 20% compression, the stresses on the cord increased very slightly. At 40% compression, the stresses on the cord became much higher than with 20% compression, and high stress distributions were observed in gray matter and the lateral and posterior funiculus. The stresses on the compressed layers were much higher than those on the uncompressed layer. Conclusions The stress distributions at 10 and 20% compression of the AP diameter of the spinal cord were very low. The stress distribution at 40% compression was much higher. The authors conclude that a critical point may exist between 20 and 40% compression of the AP diameter of the cord such that when the degree of the compression exceeds this point, the stress distribution becomes much higher, and that this may contribute to myelopathy.


2004 ◽  
Vol 16 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Sait Naderi ◽  
Uğur Türe ◽  
T. Glenn Pait

The first reference to spinal cord injury is recorded in the Edwin Smith papyrus. Little was known of the function of the cord before Galen's experiments conducted in the second century AD. Galen described the protective coverings of the spinal cord: the bone, posterior longitudinal ligament, dura mater, and pia mater. He gave a detailed account of the gross anatomy of the spinal cord. During the medieval period (AD 700–1500) almost nothing of note was added to Galen's account of spinal cord structure. The first significant work on the spinal cord was that of Blasius in 1666. He was the first to differentiate the gray and white matter of the cord and demonstrated for the first time the origin of the anterior and posterior spinal nerve roots. The elucidation of the various tracts in the spinal cord actually began with demonstrations of pyramidal decussation by Mistichelli (1709) and Pourfoir du Petit (1710). Huber (1739) recorded the first detailed account of spinal roots and the denticulate ligaments. In 1809, Rolando described the substantia gelati-nosa. The microtome, invented in 1824 by Stilling, proved to be one of the fundamental tools for the study of spinal cord anatomy. Stilling's technique involved slicing frozen or alcohol-hardened spinal cord into very thin sections and examining them unstained by using the naked eye or a microscope. With improvements in histological and experimental techniques, modern studies of spinal cord anatomy and function were initiated by Brown-Séquard. In 1846, he gave the first demonstration of the decussation of the sensory tracts. The location and direction of fiber tracts were uncovered by the experimental studies of Burdach (1826), Türck (1849), Clarke (1851), Lissauer (1855), Goll (1860), Flechsig (1876), and Gowers (1880). Bastian (1890) demonstrated that in complete transverse lesions of the spinal cord, reflexes below the level of the lesion are lost and muscle tone is abolished. Flatau (1894) observed the laminar nature of spinal pathways. The 20th century ushered in a new era in the evaluation of spinal cord function and localization; however, the total understanding of this remarkable organ remains elusive. Perhaps the next century will provide the answers to today's questions about spinal cord localization.


2010 ◽  
Vol 132 (6) ◽  
Author(s):  
C. D. Bertram

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.


Sign in / Sign up

Export Citation Format

Share Document