ABSTRACT
OBJECTIVE: The current cervical disc arthroplasty is limited by postoperative facet joint arthritis, heterotopic ossification and segmental kyphosis. The total Frisbee disc, which has an upper convex/concave non-spherical surface and a lower flat sliding surface, is a new approach for improved outcomes. Prior to clinical application, safety and suitability tests are required. METHODS: The Frisbee is the first 3rd generation disc according to a new classification of total disc because it can precisely mimic the segmental ROM, including the soft limitation of axial rotation. The ISO 18192-1 test was carried out to determine the rate of wear debris. A FE model was used to assess the safety of prosthetic components. In the sagittal plane several variables to determine the most favorable lordotic angle were evaluated. RESULTS: Two angled prosthetic plates are safer than one sliding angled core to prevent the displacement. The lordosis of 7° of the Frisbee leads to kyphosis of no more than 2° without reduction of the ROM. The wear rate of the Frisbee is five times smaller compared to an FDA-approved disc with a spherical sliding surface. CONCLUSIONS: Based on the test results, the clinical application of Frisbee can now be studied. The postoperative kyphosis observed with other devices is not an issue with the Frisbee design. Physiological ROM is combined with the significant reduction of wear debris. For these reasons the Frisbee has the potential to provide a better balanced segmental loading reducing the degeneration of the joint surface and heterotopic ossification. .
OBJETIVO: A atual artroplastia de disco cervical é limitada pela artrite facetária pós-operatória, pela ossificação heterotópica e pela cifose segmentar. O disco Frisbee total, que tem face superior não-esférica convexo-côncava e face inferior plana e deslizante, é uma nova modalidade para melhores resultados. Antes da aplicação clínica, são necessários testes de segurança e adequação. MÉTODOS: O Frisbee é o primeiro disco de 3ª geração, de acordo com uma nova classificação de disco total, pois pode imitar precisamente a AM segmentar, incluindo a limitação suave da rotação axial. O teste ISO 18192-1 foi realizado para determinar a taxa de resíduos de desgaste. Um modelo de FE foi utilizado para avaliar a segurança dos componentes protéticos. No plano sagital, foram avaliadas diversas variáveis para determinar o ângulo de lordose mais favorável. RESULTADOS: Duas placas protéticas anguladas são mais seguras para evitar o deslocamento do que um núcleo angulado deslizante. A lordose de 7° do Frisbee leva a uma cifose de não mais de 2°, sem redução da AM. A taxa de desgaste do Frisbee é cinco vezes menor em comparação com um disco aprovado pela FDA, com superfície de deslizamento esférica. CONCLUSÕES: Com base nos resultados dos testes, a aplicação clínica do Frisbee pode, agora, ser estudada. A cifose pós-operatória, observada com outras próteses não constitui problema com o desenho do Frisbee. A AM fisiológica é combinada com a redução significativa dos detritos de desgaste. Por essas razões o Frisbee tem o potencial de fornecer uma carga segmentar mais equilibrada, reduzindo a degeneração da face articular e a ossi...
OBJETIVO: La actual artroplastia de disco cervical es limitada por la artritis facetaria posoperatoria, por la osificación heterotópica y por la cifosis segmentaria. El disco Frisbee total, que tiene faz superior no esférica, convexo-cóncava e faz interior plana y deslizante, es una nueva modalidad para mejores resultados. Antes de la aplicación clínica, se necesita de pruebas de seguridad y adecuación. MÉTODOS: El Frisbee es el primer disco de la tercera generación, de acuerdo con una nueva clasificación de disco total, pues puede imitar, con precisión, la AM segmentaria, incluyendo la limitación suave de la rotación axial. La prueba ISO 18192-1 fue realizada para determinar la tasa de residuos de desgaste. Un modelo de FE fue utilizado para evaluar la seguridad de los componentes protéticos. En el plano sagital, se evaluaron diversas variables para determinar el ángulo más favorable de lordosis. RESULTADOS: Dos placas protéticas anguladas son más seguras, para evitar el desplazamiento, que un núcleo angulado deslizante. La lordosis de 7mo del Frisbee lleva a una cifosis de no más de 2do, sin reducción de la AM. La tasa de desgaste del Frisbee es cinco veces menor en comparación con un disco aprobado por la FDA, con superficie esférica de deslizamiento. CONCLUSIONES: Con base en los resultados de las pruebas, la aplicación clínica del Frisbee puede ser estudiada en la actualidad. La cifosis posoperatoria, observada con otras prótesis, no es un problema con el diseño del Frisbee. La AM fisiológica se combina con la reducción significativa de los detritos de desgaste. Por esas razones, el Frisbee tiene el potencial para suministrar una carga segmentaria más equilibrada, reduciendo la degeneración de la fase articular y la osificación heterotópica. .
Subject(s)
Joint Prosthesis , Arthroplasty , Total Disc Replacement , Intervertebral DiscABSTRACT
OBJECT: The goal of this study was to assess whether a stable but nonrigid nonfusion implant can stabilize the spine in degenerative diseases and also prevent instability following decompression. Instrumented spondylodesis is a recognized surgical treatment in degenerative disease of the lumbar spine. However, pain can develop at the bone graft donor site and the operative trauma can be very stressful in elderly patients, and it is suspected that there may be increased degenerative changes in the adjacent segments. In 2002, a nonrigid but rotationally stable pedicle screw and rod system was introduced, which could be used without additional fusion (referred to hereafter as the Cosmic system). METHODS: A total of 139 patients with degenerative disease of the lumbar spine underwent spinal stabilization with the Cosmic system without additional spondylodesis. Seventy patients had an additional decompression. The minimum follow-up was 2 years. The perioperative course, the clinical results, and the erect anteroposterior and lateral radiographs were recorded and compared with the preoperative data. The data were obtained from 6 different spine centers in Europe and documented on an Internet platform. RESULTS: The Oswestry Disability Index score improved from 48.9% to 22.5%, and the visual analog scale score decreased from 7.3 to 2.5. Lumbar lordosis did not change, nor did the adjacent disc height. Eleven patients underwent revision, 4 of them for implant failure. Of the 139 patients, 110 assessed the result as excellent, very good, or good; 24 as fair; and 5 as poor. A total of 122 patients would undergo surgery again. There were no significant differences between patients with or without an additional decompression. CONCLUSIONS: The Cosmic system is a stable but nonrigid posterior nonfusion system. Implant complications are low and the clinical outcome is good. Longer follow-up is necessary to confirm the 2-year results.
