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This study examined and compared the effectiveness of woven vicryl (polyglactin 910) mesh and lyophilized cadaver dura (Lyodura) for the repair of spinal dural defects. A woven vicryl mesh was used to repair spinal dural defects in 16 mongrel dogs. As an internal control, all animals had a separate dural incision that was closed with 9-0 vicryl suture. Animals were killed, and results were evaluated at 4, 8, 12, and 24 weeks. The repair of dural defects was achieved in all animals, and there were no cases of pseudo-meningocele formation, cerebrospinal fluid leakage, or postoperative infection. The vicryl mesh served as a latticework for formation of a neodural membrane. Inflammatory or reactive response to vicryl mesh was minimal, and no adhesion to underlying neural structures was noted. The neodural membrane formed in the animals in which lyophilized dura was employed was usually thicker than those in which vicryl mesh was used and was associated with thick arachnoid-neural adhesions in two of eight animals. We believe vicryl mesh is a suitable dural substitute and offers promise for use in clinical situations.

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The search for an ideal substance for duraplasty has stimulated clinical and experimental investigations. To date a large number of materials have been employed for dural repair, although there is as yet no unanimity regarding the ideal material. Most of these studies have been concerned with cranial dura, and spinal duraplasty has received less attention. This study was designed to examine the repair of spinal dural defects in the dog. The materials chosen for this experiment were autologous fat, a polyester fiber mesh (Mersilene) and silicone-coated Dacron (Dura Film). Nineteen dogs were used in this study. Following lumbar laminectomy and the excision of elliptical pieces of dura (1.0 X 0.5 cm) at three noncontiguous levels, each of the defects was repaired using one of the three materials. Groups of animals were sacrificed at each of 3, 6, 12, and 24 weeks after dural repair. The lumbar region was removed en bloc and prepared for histological examination. Repair of the dural opening was achieved in all cases. The polyester fiber mesh was quite effective for dural repair, serving as a scaffold through which a neomembrane grew and united the dural edges. The results with autologous fat were similarly favorable. On the other hand, results with silicone-coated Dacron showed encapsulation by connective tissue, with the ventral aspect of the graft frequently compressing the underlying cord.

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Two cases are presented in which the patients developed an unusual complication following the use of an artificial dural substitute, silicone-coated Dacron (Dura Film). Both patients had undergone removal of a tumor and involved dura. The first patient developed a very thick connective-tissue capsule of the graft material which simulated a recurrent tumor. The second patient developed an acute hemorrhage initially thought to be an acute subdural hematoma beneath the artificial dura 9 weeks after tumor removal and implantation of the graft. A review of the literature and proposed mechanisms of these complications are presented.

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A new technique is described that minimizes the damage to neural tissues caused by the cortical incisions that must be made when operating on intracerebral or intraventricular lesions. Symmetric cortical incisions were made bilaterally in the same region of the middle suprasylvian gyrus in six dogs. Blunt dissection was performed on the right side. A new technique, which utilizes a balloon catheter, was employed on the left side. A greater hemiparesis was observed on the left side in all dogs. There was a mild but definite hemiparesis on the right side in four dogs, which improved within 2-3 days postoperatively. The dogs were killed on the sixth postoperative day. The Fink-Heimer technique for selective staining of degenerating axons and their terminal boutons was used to determine the extent of neuronal damage. Histologic studies support clinical observations in the experimental animal that the neural damage resulting from cortical incision is significantly decreased when the balloon catheter technique is applied.

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Cells from cranial and spinal arachnoid membranes of humans were grown in culture. Their growth characteristics, morphology and details of their cytoskeletal composition are described. Arachnoid membranes, obtained at autopsy, were finely minced and incubated in tissue culture medium. Monolayers of cells of homogeneous morphology grew from these tissue fragments. The cells were flat and polygonal. They divided slowly to form nonoverlapping monolayers of low cell density. Electron microscopic examination of cultured arachnoid cells revealed numerous desmosome-like tight junctions and abundant intermediate filaments (tonofilaments). Both morphological features are characteristic of arachnoid cells in situ, but not of cells in the fibroblast-rich dura mater. Immunofluorescence microscopy with monoclonal antibodies demonstrated cytokeratin in the cytoplasm of primary cultures of arachnoid cells. Thus we demonstrated that these cultured cells retained certain of the specific differentiated properties of arachnoid cells in situ and that they are not fibroblasts (which lack tight junctions and cytokeratins). To our knowledge, there have been no previous reports of in vitro growth of arachnoid cells. This in vitro model should be useful in studying the response of arachnoid cells to a variety of substances thought to be involved in the chronic inflammatory condition of the meninges known as arachnoiditis.

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Autologous fat grafts have been used in a number of surgical procedures, yet properties of fat as a transplant material have remained unclear. This study was designed to compare experimental observations of subcutaneous fat grafts in mice with clinical observations of autologous fat grafts placed over the dura following laminectomy in humans. Subcutaneous fat grafts were observed daily in 75 CFl mice with the use of modified Algire back chambers. Grafts were examined histologically and histochemically at intervals up to 60 days after transplantation. Gross and microscopic observations suggest that fat grafts went through a period of initial breakdown of fat cells which was followed by revascularization. This resulted in normal appearing fat, although a smaller volume than the original graft. Three samples of autologous fat grafts from humans were removed during reoperation in the lumbar region up to 22 months after the original procedure. Histological examination revealed revascularized grafts reduced in size: the fat was normal and never replaced by scar tissue.

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A single case of back pain due to Blastomyces dermatitidis infection limited solely to the skeleton is reported with a discussion of the differential diagnosis. This rare disease must be differentiated from other destructive bone lesions such as tuberculosis or tumors because of the availability of effective treatment.

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This study evaluates the histological and histochemical changes and osteogenicity of Synthos (tricalcium phosphate ceramic) implanted in the cervical intervertebral space. The cervical vertebrae from C-3 to C-6 were exposed in 20 dogs, and discectomy was performed at the third and fifth spaces. A dowel of Synthos was inserted into the third space, and a piece of fresh autologous graft from the humerus was inserted into the fifth space. The animals were divided into five groups with four animals in each. Four animals were sacrificed at each of 3, 6, 12, 18, and 22 weeks after the procedure. The C-3 to C-6 vertebrae were removed en bloc. One-half of each specimen was processed for histological examination of bone development, while the other half was processed for the two-color fluorescent labeling technique of Suzuki and Matthews for determination of osteogenesis at the time of operation and sacrifice. Various degrees of compression of the Synthos dowel were noted, with anterior and/or posterior displacement of the implant in 70% of the cases. Results indicate that the Synthos implant was biochemically and biomechanically unacceptable for the purposes of this investigation.

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The syndrome of massive and sometimes fatal epistaxis from an aneurysm of the internal carotid artery is reviewed. Two cases are reported in which exsanguination occurred with anterior and posterior gauze packing in place. The use of standard methods for controlling severe epistaxis in this syndrome was a futile exercise. This distressing and frustrating experience prompted the development of an emergency method to prevent exsanguination pending definitive surgical treatment. A description of this technique is presented and a proposal made for its use.

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A modification of the Mayfield aneurysm clip is described which is thought to decrease the chance of slippage of the clip, mainly in the case of large-necked and atherosclerotic aneurysms.

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This has been a review of some of the movements of the cervical spine. Much data remain to be accumulated and certainly much work must be done to evaluate the effect of forces in various directions upon these movements. Perhaps an improved understanding of these movements in association with an understanding of the pathogenesis of disc degeneration will enable us to better understand the development of spondylosis. Most important this review uncovers the fallacy of laying the blame for the development of cervical spondylosis solely at the door of increased or decreased mobility at certain area. Physical stress and tissue degeneration must be playing a significant role.

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