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Literatura académica sobre el tema "Stabilità posteriore"

Autor: Grafiati

Publicado: 10 de marzo de 2023

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Artículos de revistas sobre el tema "Stabilità posteriore"

RE, M., M. IACOANGELI, L. DI SOMMA, L. ALVARO, D. NASI, G. MAGLIULO, F. M. GIOACCHINI, D. FRADEANI y M. SCERRATI. "Approccio endoscopico endonasale alla giunzione craniocervicale: l’importanza di preservare o ricostruire l’arco anteriore dell’atlante". Acta Otorhinolaryngologica Italica 36, n.º 2 (abril de 2016): 107–18. http://dx.doi.org/10.14639/0392-100x-647.

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Riportiamo la nostra esperienza con l’approccio endoscopico endonasale (EEA) in una serie consecutiva di 10 pazienti affetti da lesioni anteriori della giunzione cranio-cervicale. L’obiettivo dello studio è analizzare l’outcome di questi pazienti focalizzando l’attenzione sulla possibilità di preservare o ricostruire l’arco anteriore di C1, quale importante elemento di stabilità della giunzione cranio-cervicale. Dal gennaio 2009 al dicembre 2013, 10 pazienti con patologia della giunzione craniocervicale sono stati operati mediante approccio endoscopico endonasale. Le lesioni trattate includevano 4 casi di non riducibile compressione bulbo-midollare extradurale anteriore della giunzione (secondarie ad artrite reumatoide o anomalie della giunzione), 4 casi di fratture inveterate di C1 o del dente dell’epistrofeo e 2 casi lesioni tumorali. La valutazione clinica pre- e postoperatoria è stata effettuata mediante la scala di Ranawat per i casi di artrite reumatoide e di Nurick per gli altri. Il follow-up radiologico comprendeva invece RM, TC e RX con prove morfo-dinamiche per eventuale preesistente severa instabilità. Dopo l’approccio EEA puro alla giunzione craniocervicale, nessun paziente ha presentato un peggioramento neurologico, né si sono verificate significative complicanze. Al follow-up medio di 31 mesi (range 14-73 mesi), un miglioramento di almeno un livello della classificazione Ranawat o Nurick si è osservato in 6 pazienti mentre gli altri 4 sono rimasti stabili. Il follow-up neuroradiologico ha documentato in tutti i casi un’adeguata decompressione bulbo-midollare, mentre nei casi di frattura di C1 o C2 una regolare fusione ossea delle rime di frattura. Nessun paziente ha presentato segni di instabilità e non è stata pertanto necessaria alcuna procedura di stabilizzazione e fusione posteriore. L’approccio endoscopico endonasale garantisce un’adeguata esposizione delle lesioni antero-mediali della giunzione craniocervicale. Nella nostra serie di pazienti tale procedura ha permesso di preservare o ricostruire l’arco anteriore di C1, evitando quindi una sintesi posteriore e la relativa perdita di movimento rotazionale C0-C2 e l’instabilità subassiale.

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Biroli, F., F. De Gonda, L. Torcello, D. Prosetti, O. Manara y V. Cassinari. "Fratture del dente dell'epistrofeo". Rivista di Neuroradiologia 2, n.º 3 (octubre de 1989): 273–78. http://dx.doi.org/10.1177/197140098900200309.

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Le fratture del dente dell'epistrofeo rappresentano circa il 15% delle fratture del rachide cervicale. Vengono esaminati venti casi consecutivi osservati presso la Divisione di Neurochirurgia di Bergamo nel triennio 1984–1987: undici casi erano del secondo tipo di Anderson-D'Alonzo, e nove casi del terzo tipo. In diciassette casi la diagnosi fu tempestiva, mentre in tre la frattura fu misconosciuta e trattata tardivamente. Nel primo gruppo, dopo aver costantemente ottenuto una buona riduzione della frattura, il trattamento iniziale è stato sempre l'applicazione di un presidio di Halo, sotto controllo scopico. II periodo medio di applicazione è stato di 115 giorni. L'unica complicazione osservata è stata il frequente allentamento delle viti del cerchio, talora con flogosi localizzate in relazione al prolungato mantenimento dell'anello. Nel secondo gruppo di pazienti, in cui è sempre stata constatata l'assenza di un callo riparativo, il nostro atteggiamento è stato interventistico, praticando un'artrodesi per via posteriore seguita da applicazione di Halo. Il protocollo di monitoraggio prevede l'esecuzione mensile di radiogrammi standard nelle due proiezioni associati ad uno studio tomografico al fine di valutare la formazione del callo osseo e l'allineamento tra i monconi di frattura. Solo dopo l'osservazione di una soddisfacente riparazione ossea si procede alla rimozione dell'Halo ed all'esecuzione di radiogrammi nelle prove funzionali di estensione e flessione per confermare la stabilità dei monconi. I risultati sono stati complessivamente buoni. Nel primo gruppo tutte le fratture di terzo tipo sono guarite con formazione di callo osseo. Una sola frattura del secondo tipo non ha mostrato alcun fenomeno riparativo a tre mesi, per cui è stata sottoposta ad intervento chirurgico come già indicato, con successiva guarigione. Nel secondo gruppo abbiamo avuto un solo parziale insuccesso dovuto ad un'infezione della ferita chirurgica, guarita comunque per seconda intenzione. In conclusione, le fratture non significativamente dislocate o angolate, siano di secondo o di terzo tipo, meritano a parer nostro un primo approccio conservativo, avendo un'alta probabilità di guarigione. Se dislocate od angolate significativamente, può essere corretto proporre elettivamente la stabilizzazione chirurgica, the rimane comunque la scelta obbligata nei casi di mancata saldatura, di pseudoartrosi o di fratture inveterate. Nel primo caso il trattamento più efficace appare quello con Halo. L'intervento chirurgico è preferibilmente eseguito, secondo varie tecniche fra cui quella da not descritta, per via posteriore.

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Manfrè, L., L. Tomarchio, D. Materazzo, M. Leonardo y C. Cristaudo. "La vertebroplastica nelle neoplasie del rachide". Rivista di Neuroradiologia 15, n.º 4 (agosto de 2002): 461–72. http://dx.doi.org/10.1177/197140090201500416.

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Nonostante il primo trattamento di vertebroplastica percutanea su uomo sia stato eseguito in un paziente affetto da angioma espansivo dell'odontoide, la letteratura scientifica ha focalizzato maggiormente l'attenzione sulle possibilità applicative dell'introduzione del cemento al polimetilmetacrilato nell'ambito di vertebre affette da crolli primitivi da patologia osteoporotica. Negli ultimi anni tuttavia la comunità scientifica ha tuttavia guardato con interesse crescente l'uso della vertebroplastica in corso di neoplasie benigne o maligne a localizzazione vertebrale. La riduzione del rischio di crollo vertebrale fa della vertebroplastica uno dei trattamenti principali nella patologia tumorale vertebrale. La metodica appare quindi sostitutiva, o comunque di sostegno, ai trattamenti radioterapici, non sempre in grado di ottenere un soddisfacente effetto antalgico, meno invasiva della vertebrectomia. In caso di angioma espansivo, infine, la vertebroplastica può precedere, ove necessario, un eventuale trattamento embolizzante con colle della lesione, riducendo il letto vascolare della stessa. Le patologie espansive delle vertebre ove è indicato il trattamento percutaneo di vertebroplastica sono rappresentate dagli angiomi espansivi, dalle localizzazioni intrasomatiche di malattia neoplastica (solitamente neoplasie della serie ematica come la Leucemia Mieloide Cronica o il Mieloma Multiplo) e dalle metastasi, purché sia risparmiato l'arco posteriore vertebrale: una sua eventuale compromissione infatti precluderebbe nella maggior parte dei casi una vera stabilità vertebrale, anche dopo il trattamento, e ridurrebbe comunque le potenzialità antalgiche dello stesso. La scomparsa del dolore dipendente dalla vertebroplastica avviene solitamente in un periodo oscillante tra le prime 24–48 h sino a 30 giorni, con una media di 7 giorni. Il principale rischio della vertebroplastica in corso di patologia tumorale consiste nella fuoriuscita del cemento in sede extravertebrale durante la sua introduzione. La vertebroplastica rappresenta oggi una nuova arma dell'arsenale a disposizione della Neuroradiologia Interventiva per il trattamento di lesioni singole o multiple di natura tumorale della colonna vertebrale.

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Hawthorne, Benjamin C., Michael R. Mancini, Ian J. Wellington, Michael B. DiCosmo, Matthew E. Shuman, Maxwell T. Trudeau, Caitlin G. Dorsey, Elifho Obopilwe, Mark P. Cote y Augustus D. Mazzocca. "Deltotrapezial Stabilization of Acromioclavicular Joint Rotational Stability: A Biomechanical Evaluation". Orthopaedic Journal of Sports Medicine 11, n.º 1 (1 de enero de 2023): 232596712211195. http://dx.doi.org/10.1177/23259671221119542.

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Background: Despite advances in surgical management of acromioclavicular (AC) joint reconstruction, many patients fail to maintain sustained anatomic reduction postoperatively. Purpose: To determine the biomechanical support of the deltoid and trapezius on AC joint stability, focusing on the rotational stability provided by the muscles to posterior and anterior clavicular rotation. A novel technique was attempted to repair the deltoid and trapezius anatomically. Study Design: Controlled laboratory study. Methods: Twelve human cadaveric shoulders (mean ± SD age, 60.25 ± 10.25 years) underwent servohydraulic testing. Shoulders were randomly assigned to undergo serial defects to either the deltoid or trapezius surrounding the AC joint capsule, followed by a combined deltotrapezial muscle defect. Deltotrapezial defects were repaired with an all-suture anchor using an anatomic technique. The torque (N·m) required to rotate the clavicle 20° anterior and 20° posterior was recorded for the following conditions: intact (native), deltoid defect, trapezius defect, combined deltotrapezial defect, and repair. Results: When compared with the native condition, the deltoid defect decreased the torque required to rotate the clavicle 20° posteriorly by 7.1% ( P = .206) and 20° anteriorly by 6.1% ( P = .002); the trapezial defect decreased the amount of rotational torque posteriorly by 5.3% ( P = .079) and anteriorly by 4.9% ( P = .032); and the combined deltotrapezial defect decreased the amount of rotational torque posteriorly by 9.9% ( P = .002) and anteriorly by 9.4% ( P < .001). Anatomic deltotrapezial repair increased posterior rotational torque by 5.3% posteriorly as compared with the combined deltotrapezial defect ( P = .001) but failed to increase anterior rotational torque ( P > .999). The rotational torque of the repair was significantly lower than the native joint in the posterior ( P = .017) and anterior ( P < .001) directions. Conclusion: This study demonstrated that the deltoid and trapezius play a role in clavicular rotational stabilization. The proposed anatomic repair improved posterior rotational stability but did not improve anterior rotational stability as compared with the combined deltotrapezial defect; however, neither was restored to native stability. Clinical Relevance: Traumatic or iatrogenic damage to the deltotrapezial fascia and the inability to restore anatomic deltotrapezial attachments to the acromioclavicular joint may contribute to rotational instability. Limiting damage and improving the repair of these muscles should be a consideration during AC reconstruction.

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Feng, Jie, Xuguang Wang y Jonathan Poterjoy. "A Comparison of Two Local Moment-Matching Nonlinear Filters: Local Particle Filter (LPF) and Local Nonlinear Ensemble Transform Filter (LNETF)". Monthly Weather Review 148, n.º 11 (noviembre de 2020): 4377–95. http://dx.doi.org/10.1175/mwr-d-19-0368.1.

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AbstractThe local particle filter (LPF) and the local nonlinear ensemble transform filter (LNETF) are two moment-matching nonlinear filters to approximate the classical particle filter (PF). They adopt different strategies to alleviate filter degeneracy. LPF and LNETF localize observational impact but use different localization functions. They assimilate observations in a partially sequential and a simultaneous manner, respectively. In addition, LPF applies the resampling step, whereas LNETF applies the deterministic square root transformation to update particles. Both methods preserve the posterior mean and variance of the PF. LNETF additionally preserves the posterior correlation of the PF for state variables within a local volume. These differences lead to their differing performance in filter stability and posterior moment estimation. LPF and LNETF are systematically compared and analyzed here through a set of experiments with a Lorenz model. Strategies to improve the LNETF are proposed. The original LNETF is inferior to the original LPF in filter stability and analysis accuracy, particularly for small particle numbers. This is attributed to both the localization function and particle update differences. The LNETF localization function imposes a stronger observation impact than the LPF for remote grids and thus is more susceptible to filter degeneracy. The LNETF update causes an overall narrower range of posteriors that excludes true states more frequently. After applying the same localization function as the LPF and additional posterior inflation to the LNETF, the two filters reach similar filter stability and analysis accuracy for all particle numbers. The improved LNETF shows more accurate posterior probability distribution but slightly worse spatial correlation of posteriors than the LPF.

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Doğan, Şeref, Seungwon Baek, Volker K. H. Sonntag y Neil R. Crawford. "Biomechanical Consequences of Cervical Spondylectomy Versus Corpectomy". Operative Neurosurgery 63, suppl_4 (1 de octubre de 2008): ONS303—ONS308. http://dx.doi.org/10.1227/01.neu.0000327569.03654.96.

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Abstract Objective: To evaluate the differences in spinal stability and stabilizing potential of instrumentation after cervical corpectomy and spondylectomy. Methods: Seven human cadaveric specimens were tested: 1) intact; 2) after grafted C5 corpectomy and anterior C4–C6 plate; 3) after adding posterior C4–C6 screws/rods; 4) after extending posteriorly to C3–C7; 5) after grafted C5 spondylectomy, anterior C4–C6 plate, and posterior C4–C6 screws/rods; and 6) after extending posteriorly to C3–C7. Pure moments induced flexion, extension, lateral bending, and axial rotation; angular motion was recorded optically. Results: After corpectomy, anterior plating alone reduced the angular range of motion to a mean of 30% of normal, whereas added posterior short- or long-segment hardware reduced range of motion significantly more (P < 0.003), to less than 5% of normal. Constructs with posterior rods spanning C3–C7 were stiffer than constructs with posterior rods spanning C4–C6 during flexion, extension, and lateral bending (P < 0.05), but not during axial rotation (P > 0.07). Combined anterior and C4–C6 posterior fixation exhibited greater stiffness after corpectomy than after spondylectomy during lateral bending (P = 0.019) and axial rotation (P = 0.001). Combined anterior and C3–C7 posterior fixation exhibited greater stiffness after corpectomy than after spondylectomy during extension (P = 0.030) and axial rotation (P = 0.0001). Conclusion: Circumferential fixation provides more stability than anterior instrumentation alone after cervical corpectomy. After corpectomy or spondylectomy, long circumferential instrumentation provides better stability than short circumferential fixation except during axial rotation. Circumferential fixation more effectively prevents axial rotation after corpectomy than after spondylectomy.

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Basu, Sanjib. "Uniform stability of posteriors". Statistics & Probability Letters 46, n.º 1 (enero de 2000): 53–58. http://dx.doi.org/10.1016/s0167-7152(99)00086-3.

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Almeida, Renato Rodrigues de, Marcio Rodrigues de Almeida, Paula Vanessa Pedron Oltramari-Navarro, Ana Cláudia de Castro Ferreira Conti, Ricardo de Lima Navarro y Henry Victor Alves Marques. "Posterior crossbite - treatment and stability". Journal of Applied Oral Science 20, n.º 2 (abril de 2012): 286–94. http://dx.doi.org/10.1590/s1678-77572012000200026.

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Ayanbayev, Birzhan, Ilja Klebanov, Han Cheng Lie y T. J. Sullivan. "Γ -convergence of Onsager–Machlup functionals: I. With applications to maximum a posteriori estimation in Bayesian inverse problems". Inverse Problems 38, n.º 2 (28 de diciembre de 2021): 025005. http://dx.doi.org/10.1088/1361-6420/ac3f81.

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Abstract The Bayesian solution to a statistical inverse problem can be summarised by a mode of the posterior distribution, i.e. a maximum a posteriori (MAP) estimator. The MAP estimator essentially coincides with the (regularised) variational solution to the inverse problem, seen as minimisation of the Onsager–Machlup (OM) functional of the posterior measure. An open problem in the stability analysis of inverse problems is to establish a relationship between the convergence properties of solutions obtained by the variational approach and by the Bayesian approach. To address this problem, we propose a general convergence theory for modes that is based on the Γ-convergence of OM functionals, and apply this theory to Bayesian inverse problems with Gaussian and edge-preserving Besov priors. Part II of this paper considers more general prior distributions.

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Chang, Hsuan-Sung, Jen-Suh Chern y Chi-Wen Long. "P-27 THE EFFECTS OF ANTERIOR AND POSTERIOR ANKLE-FOOT-ORTHOSIS ON POSTURAL STABILITY IN HEMIPLEGIC PATIENTS". Proceedings of the Asian Pacific Conference on Biomechanics : emerging science and technology in biomechanics 2007.3 (2007): S115. http://dx.doi.org/10.1299/jsmeapbio.2007.3.s115.

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Más fuentes

Tesis sobre el tema "Stabilità posteriore"

Hartwich, Kathleen, Alejandro Lorente Gomez, Jaroslaw Pyrc, Radosław Gut, Stefan Rammelt y René Grass. "Biomechanical Analysis of Stability of Posterior Antiglide Plating in Osteoporotic Pronation Abduction Ankle Fracture Model With Posterior Tibial Fragment". Sage, 2017. https://tud.qucosa.de/id/qucosa%3A35489.

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Background: We performed a biomechanical comparison of 2 methods for operative stabilization of pronation-abduction stage III ankle fractures; group 1: Anterior-posterior lag screws fixing the posterior tibial fragment and lateral fibula plating (LSLFP) versus group 2: locked plate fixation of the posterior tibial fragment and posterior antiglide plate fixation of the fibula (LPFP). Methods: Seven pairs of fresh-frozen osteoligamentous lower leg specimens (2 male, and 5 female donors) were used for the biomechanical testing. Bone mineral density (BMD) of each specimen was assessed by means of dual-energy x-ray absorptiometry. After open transection of the deltoid ligament, an osteotomy model of pronation abduction stage III ankle fracture was created. Specimens were systematically assigned to LSLFP (group 1, left ankles) or LPPFP (group 2, right ankles). After surgery, all specimens were evaluated via CT to verify reduction and fixation. Axial load was then applied onto each specimen using a servohydraulic testing machine starting from 0 N (Zwick/Roell, Ulm, Germany) at a speed of 10 N/s with the foot fixed in a 10 degrees pronation and 15 degrees dorsiflexion position. Construct stiffness, yield, and ultimate strength were measured and dislocation patterns were documented with a high-speed camera. The normal distribution of all data was analyzed using Shapiro-Wilk test. The group comparison was performed using paired Student t test. Statistical significance was assumed at a P value of .05. Results: All specimens had BMD values consistent with osteoporosis. BMD values did not differ between the left and right ankles of the same pair (P = .762). The mean BMD values between feet of men (0.603 g/cm²) and women (0.329 g/cm²) were statistically different (P = .005). The ultimate strength for LSLFP (group 1) with 1139 ± 669 N and LPPFP (group 2) with 2008 ± 943 N was statistically different (P = .036) as well as the yield in LSLFP (group 1) 812 ± 452 N and LPPFD (group 2) 1292 ± 625 N (P = .016). Construct stiffness trended to be higher in group 2 (179 ± 100 kNn) compared to group 1 (127 ± 73 kN/m) but this difference was not statistically significant (P = .120). BMD correlated with bone-construct failure. Conclusion: Fixation of the posterior tibial edge with a posterolateral locking plate resulted in higher biomechanical stability than anterior-posterior lag screw fixation in an osteoporotic pronation-abduction fracture model. Clinical Relevance: The clinical implication of this biomechanical study is that the posterior antiglide plating might be advantageous in patients with osteoporotic pronation abduction stage III ankle fracture.

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Olanlokun, Kola Folorunsho. "Control of knee stability by internal devices". Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325853.

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Bridgeman, Leila. "Stability and a posteriori error analysis of discontinious Galerkin methods for linearized elasticity". Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95054.

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We consider discontinuous Galerkin finite element methods for the discretization of linearized elasticity problems in two space dimensions. Inf-sup stability results on the continuous and discrete level are provided. Furthermore, we derive lower and upper a posteriori error bounds that are robust with respect to nearly incompressible materials, and can easily be implemented within an automatic mesh refinement procedure. The theoretical results are illustrated with a series of numerical experiments.
Nous considérons les méthodes de Galerkin pour la discrétisation des relations déformations-déplacements linéaires en deux dimensions d'espace. Des résultats du stabilité inf-sup sur les niveaux continus et discrets sont fournis. En plus, nous dérivons des limites inférieurs et supérieures pour l'erreur a posteriori qui peuvent être utilisées dans des procédures de maillage automatisées sans difficulté et qui demeurent robustes dans le cas des matériaux qui ne sont presque pas compressibles. Les résultats théoriques sont illustrés par des expériences numériques.

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Sasidhar, Vadapalli. "Stability imparted by a posterior lumbar interbody fusion cage following surgery : a biomechanical evaluation /". See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1092370385.

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Thesis (M.S.B.)--University of Toledo, 2004.
Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Bioengineering." Bibliography: leaves 4-11.

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Mathieu-Job, Martine y Gérard Thomas. "Fiabilite dimensionnelle des dents prothetiques posterieures : etude metrologique et analyse statistique". Nancy 1, 1989. http://www.theses.fr/1989NAN13401.

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Sei, Alain. "Etude de schemas numeriques pour des modeles de propagation d'ondes en milieux heterogenes". Phd thesis, Université Paris Dauphine - Paris IX, 1991. http://tel.archives-ouvertes.fr/tel-00584224.

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Les methodes d'inversion par moindres carres necessitent la simulation de propagation d'ondes modelisees par des equations lineaires. C'est dans cette partie modelisation que se situe la majeure partie de notre travail qui comporte quatre chapitres. Dans le premier chapitre, nous etudions l'inversion d'un milieu localement perturbe, c'est a dire que nous recherchons une heterogeneite de forme donnee dans une matrice homogene. Nous montrons dans ce cas simple l'influence de la frequence de la source sur la non-linearite de la fonction cout. Dans le second chapitre, nous introduisons et analysons une famille de schemas numeriques pour l'equation des ondes acoustiques en milieu homogene. Ces schemas d'ordre sont deux ou quatre en temps et d'ordre quelconque en espace. Nous avons estime le cout informatique des simulations et preconise un choix du nombre de points par longueur d'onde et du nombre de points par periode. Ceci donne alors les pas d'espace et de temps. Dans le troisieme chapitre nous etudions la stabilite et la precision de cette famille de schemas numeriques en milieu heterogene. Nous obtenons des resultats quelque soit l'heterogeneite du milieu, et donnons l'ordre d'approximation de ces schemas numeriques en milieux heterogenes. Nous etudions egalement les condition absorbantes eponges. Dans le dernier chapitre nous nous sommes interesse a une estimation d'erreur a posteriori pour l'equation des ondes en milieu unidimensionnel. Ces estimations sont generalisables au cas bidimensionnel. Elles permettent de mesurer l'erreur commise sur la solution a l'aide de quantites calculables; donc on peut par procedure adaptive regler les pas de temps et d'espace.

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Novellino, Marcelo Michele. "Avaliação da estabilidade, por meio da análise da frequência de ressonância (RFA), de implantes colocados na maxila posterior variando somente o tratamento de superfície: ensaio clínico randomizado". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/23/23150/tde-25062018-111047/.

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Contexto: Modificações químicas da superfície dos implantes dentários com o objetivo de aumentar a molhabilidade resultam em uma osseointegração mais rápida e melhor. Objetivo: O objetivo deste estudo foi avaliar o quociente de estabilidade do implante (ISQ) (implant stability quotient) de implantes com geometria idêntica, mas com tratamentos de superfície diferentes: jateamento de areia e ataque ácido (SAE) e a mesma superfície com uma modificação química para aumento da hidrofilia, dentro das primeiras 16 semanas de cicatrização. Materiais e Método: neste estudo clínico randomizado um total de 64 implantes (32 SAE - Grupo Controle e 32 SAE modificado - Grupo Teste) com o mesmo desenho geométrico, comprimento e diâmetro (cônico e compressivo, 4,3x10 mm) foram colocados na maxila posterior de 21 pacientes parcialmente desdentados. Os valores de ISQ foram coletados no pós - cirúrgico imediato (T0), com 1 semana (T1), 2 (T2), 3 (T3), 5 ( T4), 8 (T5), 12 (T6) e 16 semanas (T7). Os resultados foram comparados por meio do ANOVA de medidas repetidas. Resultados: O grupo teste apresentou valores de ISQ mais altos que o grupo controle (ANOVA - p<0,01) a partir da 5a semana. Quando comparados os grupos em relação ao tempo necessário para se atingir o ISQ >= 70 como uma referência, houve uma diferença estatisticamente significante (p<0,01) e um Hazard Ratio de 2,24 (IC 1,62-3,11). No acompanhamento de um ano um paciente com 2 implantes abandonou a pesquisa, e estes não puderam mais ser avaliados. A taxa de sobrevida de ambos grupos foi de 100% após um ano de acompanhamento. Conclusão: O presente estudo sugere que implantes com superfície hidrofílica osseointegram mais rápido que implantes com superfície SAE convencional. O ganho de estabilidade do grupo teste foi 2,24 vezes mais rápido que do grupo controle após 5 semanas de avaliação em leitos na maxila posterior.
Background: Chemical modifications of dental implant surface, to improve the wettability, results in a faster and better osseointegration. Purpose: The aim of this study was to evaluate the implant stability quotient (ISQ) of implants with the same design, treated with two different surfaces: Sandblasted Acid-Etched (SAE) and hydrophilic SAE, within the initial 16 weeks of healing. Materials and Method: For this RCT a total of 64 implants (32 SAE - Control Group and 32 modified SAE - Test Group) with the same design, length and diameter (conical and compressive, 4.3x10 mm) were inserted in the posterior maxillae of 21 patients partially edentulous. The ISQ values were collected at the post-surgery (T0), 1-week (T1), 2-weeks (T2), 3- weeks (T3), 5-weeks (T4), 8-weeks (T5), 12-weeks (T6) and 16-weeks (T7). The statistic test was ANOVA. Results: Test group presented ISQ values higher than the Control group (ANOVA - p<0.01) from 5th week. When comparing groups regarding the amount of time required to achieve ISQ >= 70 as a reference, there was a statistically significant difference (p <0.01), and a HR (Hazard Ratio) of 2.24 (CI 1.62- 3.11). At the one-year follow up, there was a drop out of one patient and two implants were no longer evaluated. Survival rate for both groups was of 100% after one year of follow up. Conclusion: The current study suggests that implants with hydrophilic surface (modified SAE) integrates faster than implants with SAE surface. Stability gain of the tested group was 2.24 times faster than the control group after five weeks of evaluation at the posterior region of maxillae.

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Hofmann, B. y O. Scherzer. "Local Ill-Posedness and Source Conditions of Operator Equations in Hilbert Spaces". Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800957.

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The characterization of the local ill-posedness and the local degree of nonlinearity are of particular importance for the stable solution of nonlinear ill-posed problems. We present assertions concerning the interdependence between the ill-posedness of the nonlinear problem and its linearization. Moreover, we show that the concept of the degree of nonlinearity com bined with source conditions can be used to characterize the local ill-posedness and to derive a posteriori estimates for nonlinear ill-posed problems. A posteriori estimates are widely used in finite element and multigrid methods for the solution of nonlinear partial differential equations, but these techniques are in general not applicable to inverse an ill-posed problems. Additionally we show for the well-known Landweber method and the iteratively regularized Gauss-Newton method that they satisfy a posteriori estimates under source conditions; this can be used to prove convergence rates results.

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Esposito, Francesco. "Biomechanical Analysis on Total Knee Replacement patients during Activities of Daily Living: Medial Pivot or Posterior Stabilized design?" Doctoral thesis, 2019. http://hdl.handle.net/2158/1152927.

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Etienne, Marie. "Improved primary stability of crestal implants in the low volume posterior maxillary bone". Master's thesis, 2020. http://hdl.handle.net/10284/9232.

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Introdução: A região edentulosa posterior maxilar apresenta muitas condições únicas e desafiadoras na odontologia do implante, como baixa qualidade óssea e volume limitado devido à presença do seio maxilar. Todos estes parâmetros influenciam diretamente a estabilidade primária de um implante dentário, fundamental para o sucesso da cirurgia e para alcançar a osseointegração do implante. Já conhecemos o princípio do enxerto do seio lateral, a fim de aumentar a altura do osso alveolar e, assim, a ancoragem do implante. Mas continua a ser uma cirurgia bastante invasiva com os riscos e complicações que ocorre. Quando a altura do resíduo ósseo não precisa ser aumentada muito ou quando é a densidade óssea que coloca um problema, quais são as técnicas menos invasivas disponíveis para nós ? Objetivos: O objetivo deste estudo é ver, em relação às técnicas atuais com osteotomias em Summers, quais inovações e benefícios podem ser obtidos a partir de novos métodos de colocação de implantes como a osseodensificação, e quais são seus limites. Resultados : A técnica de osseodensificação parece promissora para aumentar a densidade óssea e, portanto, a estabilidade do implante, mas os estudos humanos devem confirmar estes resultados. O sinus lift indireto com osteotomas continua a ser a técnica de escolha durante a perda óssea vertical moderada, permanecendo quando mesmo muito menos invasivo do que o sinus lift lateral. Materiais e Métodos: Para responder a este problema pesquisamos artigos em bases de dados científicas (Pubmed, Medineplus, Hubmed, B-On) com as palavras-chave "elevador sinusal", "osseodensificação" "estabilidade primária" osteotomos "Densah burs""e os critérios de selecção foram a língua (artigos em inglês, francês ou português). Encontramos 145 artigos e selecionamos 80 , publicados entre 1986 e 2019.
Introduction: The maxillary posterior edentulous region presents many unique and challenging conditions in implant dentistry, such as poor bone quality and limited volume due to the presence of the maxillary sinus. All these parameters directly influence the primary stability of a dental implant, which is fundamental to the success of surgery and to achieve implant osseointegration. We already know the principle of lateral sinus grafting, in order to increase the height of the alveolar bone and thus the anchoring of the implant. But it remains a pretty invasive surgery with the risks and complications that it occurs. When the height of bone residual does not need to be increased much or when it is bone density that poses a problem, what are the less invasive techniques available to us ? Objectifs: The objective of this study is to see, in relation to current techniques with osteotomes in Summers, what innovations and benefits can be gained from new methods of implant placement such as osseodensification, and what are their limits. Results : The osseodensification technique seems promising to increase bone density and thus implant stability, but human studies need to confirm these results. Indirect sinus lift with osteotomes remains the technique of choice during a moderated vertical bone loss, still remaining much less invasive than lateral sinus lift. Materials and Methods: To answer this problem we searched articles in scientific databases (Pubmed, Medineplus, Hubmed, B-On) with the keywords "sinus lift", "osseodensification" "primary stability" "Densah burs" osteotomes"and the selection criteria was the language (English, French or Portuguese articles). We found 145 articles and we selected 80 , published between 1986 and 2019.

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Libros sobre el tema "Stabilità posteriore"

Howell, Valerie L., Margaret M. Collins y Lauryn R. Rochlen. Anesthesia for Posterior Fossa Mass. Editado por David E. Traul y Irene P. Osborn. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190850036.003.0002.

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Lesions of the posterior fossa provide challenges for both anesthesiologists and surgeons due to this intracranial cavity’s rigid boundaries, minimal compliance, and vital neuronal contents. Common surgeries in the posterior fossa include excision of tumors, correction of congenital and acquired craniovertebral junction anomalies, and relief of pressure on the brainstem. Symptoms can present acutely and are most commonly due to compression of brain components, obstruction of cerebrospinal fluid, or increased intracranial pressure. Careful planning of the anesthetic is important to prevent exacerbation of preexisting symptoms or pathology, optimize the surgical resection, and aid in the quick diagnosis of postoperative complications. A variety of complications may occur in the perioperative period, many of which are unique to the posterior fossa or surgical approach. Anesthetic management focuses on prevention of common complications, maintenance of hemodynamic stability, facilitation of intraoperative neurophysiologic monitoring. and early postoperative neurologic evaluation through timely emergence.

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Capítulos de libros sobre el tema "Stabilità posteriore"

Ghosh, Jayanta K., Subhashis Ghosal y Tapas Samanta. "Stability and Convergence of the Posterior in Non-Regular Problems". En Statistical Decision Theory and Related Topics V, 183–99. New York, NY: Springer New York, 1994. http://dx.doi.org/10.1007/978-1-4612-2618-5_15.

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Ulrich, Chr, O. Woersdoerfer, L. Claes y F. Magerl. "Comparative Stability of Anterior or Posterior Cervical Spine Fixation—in vitro Investigation". En Cervical Spine I, 65–69. Vienna: Springer Vienna, 1987. http://dx.doi.org/10.1007/978-3-7091-8882-8_10.

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Hoeher, J., C. Harner, S. L. Y. Woo y T. Tiling. "Die Rolle des Popliteus-Komplexes für die posteriore Stabilität des Kniegelenks — Eine biomechanische Analyse am Leichenknie". En Hefte zur Zeitschrift „Der Unfallchirurg“, 903–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60913-8_336.

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Ulrich, Ch, R. Kalff, L. Claes, O. Woersdoerfer y H. J. Wilke. "The Relevance of Torsional Stability to Anterior and Posterior Cervical Spine Fixation Procedures — an Experimental Study". En Cervical Spine II, 272–76. Vienna: Springer Vienna, 1989. http://dx.doi.org/10.1007/978-3-7091-9055-5_44.

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Tuite, Michael J. y Christian W. A. Pfirrmann. "Shoulder: Instability". En IDKD Springer Series, 1–9. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-71281-5_1.

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AbstractGlenohumeral instability is the inability to keep the humeral head centered in the glenoid fossa. Glenohumeral instability can be classified according to etiology and direction of instability. The glenoid labrum, the glenohumeral ligaments, and the bony structures contribute to the stability glenohumeral joint and need to be addressed with imaging. One of the difficulties with accurately diagnosing labral tears on MR imaging is the normal labral variants, which can sometimes appear similar to tears. The location and extent of a Hill-Sachs lesion and glenoid rim defects need to be related to recognize engaging Hill-Sachs lesions or off-track situations. There are several types of labral tears that are not associated with a prior dislocation. SLAP tears are one of the more common tears of the labrum and can sometimes be difficult to distinguish from a normal variant superior sublabral recess. Labral tears in overhead thrower occur in the posterosuperior labrum, adjacent to the posterior rotator cuff tears in these athletes. Tears in the posterosuperior labrum are also associated with spinoglenoid notch paralabral cysts, which can be painful and cause external rotation weakness.

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Link, Isabell y Christian Fünfgeld. "Pelvic Floor Disorders in Females: An Overview on Diagnostics and Therapy". En Pelvic Floor Dysfunction - Symptoms, Causes, and Treatment. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101260.

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Pelvic floor disorders have multifactorial reasons and can have a huge impact on a woman’s life. They can result in descensus of bladder, uterus, vagina or rectum and are often accompanied by incontinence. Symptoms like downward pressure, pain, incontinence or bladder voiding dysfunction develop slowly and are still highly taboo. Gynecology differentiates between descensus of the anterior, central and posterior compartment. A descensus in the anterior compartment causes a cystocele, with can either present as a pulsation cystocele or a traction cystocele. A descensus of the apical compartment leads to a uterine prolapse or vaginal stump descensus, while a descensus of the posterior compartment results in a recto- or enterocele. Urinary incontinence can be divided into stress and urge incontinence. The most important tool for the diagnosis of pelvic floor disorders is the clinical examination. Regarding the therapy of pelvic floor disorders, conservative therapy measures should first be offered. If these fail, an individually optimized surgical therapy should follow. The spectrum of surgical possibilities has expanded considerably in the last three decades. In particular, implanting alloplastic meshes has improved long-term stability. Finally, preventive measures also play a central role.

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Horng, J., XC Liu, J. Thometz, C. Tassone y A. Duey-Holtz. "Evaluation of plantar pressures and center of pressure trajectories in Adolescent Idiopathic Scoliosis". En Studies in Health Technology and Informatics. IOS Press, 2021. http://dx.doi.org/10.3233/shti210451.

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Adolescent idiopathic scoliosis (AIS) has been postulated to affect gait patterns and postural stability due to its effect on center of body mass. 1) Determine the correlation between Cobb angle and COP in the anterior-posterior (AP) direction, COP in the medial-lateral (ML) direction, COP oscillation (COP-O) from midline walking, peak pressures, and pressure-time integrals (loading) at 10 anatomic foot segments; 2) Determine the differences in COP-AP, COP-ML, COP-O, and peak plantar pressures at 10 anatomic foot segments between the normal group and the AIS group. All patients wore a gown to expose the posterior trunk and underwent evaluation with Formetric 4D (DIERS International GmbH, Schlangenbad, Germany) while walking on the treadmill at 2 km/hour for 15 seconds. A total of 24 pressure metrics at 10 anatomic foot segments were evaluated. We then analyzed the data using t-test and linear regression analyses.16 patients were assigned to a normal group (Cobb angle 10° or less, n=4) or AIS group (Cobb greater than 10°, n=12). Of note, AIS patients had statistically significant lower max. pressures at the hallux and the 2nd, 4th, 5th metatarsal head compared to the normal group. Additionally, there was a statistically significant linear association between Cobb angle and both hallux max. pressure and hallux pressure-time integral (P<0.05). Reduced peak plantar pressures before the toe-off phase of gait cycle indicate that AIS patients may lean backwards and have posterior postural sway, which may be associated with hypokyphosis during walking.

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Read, Paul J. "Cervical Spine Trauma". En Musculoskeletal Imaging Volume 1, editado por Imran M. Omar, 9–15. Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780190938161.003.0002.

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Chapter 2 aims to introduce the reader to important concepts relevant to interpreting imaging of the cervical spine after trauma. Cervical spine traumatic injuries are categorized by mechanism of injury, stability, and location. The most common mechanisms of injury in the cervical spine are hyperflexion, hyperextension, and axial compression, and these mechanisms often result in predictable radiographic abnormalities. Injuries can be divided into those that are stable and those that are unstable. In addition, the 3-column model, which divides the spine into anterior, middle, and posterior columns, is described. Pertinent anatomy and imaging strategies will be reviewed followed by a pattern-based review of injuries, typical imaging findings, and standard treatment options.

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O’Keeffe, Michael, Kiran Khursid, Peter L. Munk y Mihra S. Taljanovic. "Sternoclavicular Joint Trauma". En Musculoskeletal Imaging Volume 1, editado por Mihra S. Taljanovic y Tyson S. Chadaz, 44–45. Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780190938161.003.0009.

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Chapter 9 discusses sternoclavicular joint trauma. The sternoclavicular joint is a synovial joint with a capsule and adjacent ligaments providing overall stability. Direct or indirect force to the shoulder from mechanisms, such as a motor vehicle collision, sporting injuries, or fall from a height, can cause sternoclavicular joint injury. The 2 main mechanisms for posterior sternoclavicular joint dislocations are discussed. Tearing of the ligaments can result in sternoclavicular joint dislocations, which are more commonly anterior and caused by a blow to the shoulder. Complications related to sternoclavicular joint injury are largely related to the mechanism of injury. CT examination is the gold standard for assessment of dislocation and any potential injury to surrounding structures.

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Yang, Sheng y Chunyang Xia. "Short-Segment Schanz Pedicle Screw Oblique Downward Fixation for Thoracolumbar Burst Fractures: A New Method for the Reduction of Intraspinal Bone Fragments". En Updates in Neurosurgery [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.108068.

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Short-segment pedicle screw internal fixation for thoracolumbar burst fracture has been widely used in clinic. When the fracture fragment enters the spinal canal seriously, it is often necessary to decompress. The authors pioneered the reduction of fracture fragments in the spinal canal by direct traction with pedicle screws implanted obliquely downward without lamina decompression. Compared with the previous pedicle screw parallel endplate fixation and lamina decompression, this new method has less trauma, better reduction and can remove the internal fixation after fracture healing. Compared with conventional pedicle screws, short-segment Schanz pedicle screws are more similar to normal posterior columns in structure and stress conduction and have better safety and stability, so the latter is more suitable for the treatment of severe burst fractures.

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Actas de conferencias sobre el tema "Stabilità posteriore"

Reuther, Katherine E., Stephen J. Thomas, Joseph J. Sarver, Jennica J. Tucker, Chang-Soo Lee, Chancellor F. Gray, David L. Glaser y Louis J. Soslowsky. "Massive Cuff Tears Alter Joint Function and Decrease Cartilage Mechanics Following Return to Overuse Activity in a Rat Model". En ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80072.

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Rotator cuff tendon tears are common conditions which can alter shoulder joint function and over time, cause secondary damage to the surrounding tissues, including the cartilage and other remaining tendons. Glenohumeral joint stability is dependent on a dynamic balance between rotator cuff forces, in particular the subscapularis anteriorly and the infraspinatus posteriorly. An intact rotator cuff stabilizes the joint, allowing for concentric rotation of the humeral head on the glenoid. However, a massive rotator cuff tear involving the supraspinatus and infraspinatus may disrupt the normal balance of forces at the joint, resulting in abnormal joint loading. This is of particular concern in populations who perform activities requiring repeated overhead activity (e.g., laborers, athletes). Our lab has previously demonstrated that restoration of the subscapularis-infraspinatus anterior-posterior force balance improves shoulder function by providing a stable fulcrum for concentric rotation of the humeral head on the glenoid [1]. However, the long term consequences caused by disruption of the anterior-posterior force balance (supraspinatus and infraspinatus tear) on the glenoid cartilage and adjacent (intact) tendons, particularly in the case of an overuse population, remains unknown. Therefore, the objective of this study was to investigate the effect of disrupting the anterior-posterior force balance on joint function and joint damage using a clinically relevant overuse model system. We hypothesized that a disrupted anterior-posterior force balance (supraspinatus and infraspinatus tear) would result in H1) decreased joint function and H2) inferior adjacent tissue (glenoid cartilage, biceps and subscapularis tendon) properties compared to an intact anterior-posterior force balance (supraspinatus only tear).

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DiAngelo, Denis J., Bobby J. McVay, Kristine M. Olney y Kevin T. Foley. "In Vitro Testing of Posterior Cervical Lateral Mass Plating Systems: Comparison of Constrained Versus Semi-Constrained Screw-Slot Connections". En ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2551.

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Abstract Interspinous or facet wiring has been the standard treatment for posterior cervical spine instability secondary to trauma or decompression (Wellmann et al., 1998). However, wire techniques may be limited when posterior elements are deficient or fractured. Alternative methods, such as posterior lateral mass plate fixation, may restore the stability of the affected region and promote fusion (Wellmann et al., 1998). The objective of the study was to determine if lateral mass plate fixation restored the stability of a reconstructed posterior destabilized cervical spine and to compare the biomechanical stability of two lateral mass plate designs: plates with screws constrained in slots (SCS) versus plates with screws unconstrained and free to translate in slots (SUS). Two posterior destabilized conditions were studied: a one-level (C4-C5) model and a two-level (C4-C6) model in which all posterior ligaments were sectioned.

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Puttlitz, Christian M., Robert P. Melcher, Vedat Deviren, Dezsoe Jeszenszky y Ju¨rgen Harms. "Construct Stability of C2 Replacement Strategies". En ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42893.

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Reconstruction of C2 after tumor destruction and resection remains a significant challenge. Most constructs utilize a strutgraft with plate or screw fixation. A novel C2 prosthesis combining a titanium mesh cage with bilateral C1 shelves and a T-plate has been used successfully in 18 patients. Supplemental posterior instrumentation includes C0-C3 or C1-C3. Biomechanical comparisons of this C2 prosthesis with traditional fixation options have not been reported. Five fresh-frozen human cadaveric cervical spines (C0-C5) were tested intact. Next, the C2 prosthesis, and strut graft and anterior plate constructs were tested with occiput-C3 and C1-C3 posterior fixation. Pure moment loads (up to 1.5 N-m) were applied in flexion and extension, lateral bending, and axial rotation. C1-C3 motion was evaluated using 3 camera motion analysis. Statistical significance was evaluated using one-way repeated measures ANOVA with Student-Newman-Keuls post hoc pairwise comparisons. All constructs provided a statistically significant decrease in motion in this C2 corpectomy model as compared to the intact condition. There was no significant difference in C1-C3 motion between the 4 constructs, regardless of whether the occiput was included in the fixation. Under these loading conditions, both the C2 prostheisis and strut-graft-plate constructs provided initial C1-C3 stability beyond that of the intact specimen. The occiput does not need to be included in the posterior instrumentation.

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Bell, C. P., S. Arno, S. Hadley, K. Campbell, M. Hall, L. Beltran, M. P. Recht, O. H. Sherman y P. S. Walker. "The Effect of Arthroscopic Partial Medial Meniscectomy on Tibiofemoral Stability". En ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80370.

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Irreparable tears of the posterior horn of the medial meniscus are the most common meniscal injury and arthroscopic partial meniscectomy is the current standard of care (1–3). However, despite the excellent results of partial meniscectomy, there is still little known regarding the effects of the size of a resection on tibiofemoral stability, as measured by laxity and anterior-posterior (AP) position. Therefore in this study, we sought to determine this by conducting three successive partial meniscectomies of the posterior horn of the medial meniscus (PMM) and measuring the laxity and AP position of the medial femoral condyle over a series of loading conditions following each resection. It was hypothesized that more than a 50% resection would result in significant changes in laxity and AP position equivalent to a 100% removal of the PMM.

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DiAngelo, Denis J., Keith A. Vossel, Kevin T. Foley y Y. Raja Rampersaud. "Biomechanical Stability of Multi-Level Inter-Body Cervical Strut-Graft Fusion With Posterior Plating Instrumentation". En ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0102.

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Abstract Strut-graft fusion with supplemental instrumentation is an accepted surgical treatment for multi-level cervical disease. There are many surgical methods for decompressing and reconstructing the cervical spine, e.g., anterior: multi-level discectomy, multi-level interbody strut-graft fusion (SG), multi-level strut-graft with anterior plate instrumentation, or posterior: multi-level laminectomy with posterior lateral mass plating instrumentation. A relatively new surgical approach that combines these methods is multi-level strut-graft fusion with posterior plating instrumentation (SGPP). Although the surgery should restore the mechanical integrity of the operated spine, little is known of the load-sharing mechanics between the SG and posterior instrumentation. Clinically, strut-grafted constructs fail by pistoning of the SG into the adjacent vertebrae, dislodgment of the SG at the vertebral interfaces, SG fracture, hardware breakage, or screw-plate extrusion. The objective of the study was to determine the biomechanical stability of SGPP spinal constructs and to study the influence of posterior plates on strut-graft loading mechanics in vitro.

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Dharia, Mehul A., Marc Muenchinger, Eik Siggelkow y Jeff E. Bischoff. "The Influence of Tibial Insert Design on Posterior Stabilized Total Knee Arthroplasty Kinematics". En ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53106.

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Posterior stabilization in PCL (Posterior Cruciate Ligament) sacrificing Total Knee Arthroplasty (TKA) can be achieved by two commonly used design concepts. Anteriorposterior (AP) stability can be provided either by the ultracongruent (UC) shape of the tibial articulation or by a posterior cruciate substitution with a central spine on the tibial insert which articulates with a transverse cam on the femoral component [1]. Clinical studies have indicated that the use of UC tibial insert design does not significantly compromise the TKA outcomes when compared with the use of posterior cruciate substituting design [2].

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Liu, Mu-Yi, Ching-Lung Tai, Wen-Huang Liang y Po-Liang Lai. "Biomechanical Comparison of Facet Spacer and Facet Screw for Lumbar Posterior Stability". En The 2nd World Congress on Electrical Engineering and Computer Systems and Science. Avestia Publishing, 2016. http://dx.doi.org/10.11159/icbes16.125.

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Scifert, Jeffrey L., Vijay K. Goel, Darin W. Smith y Vincent C. Traynelis. "In Vitro Quasi-Static and Cyclic Biomechanics of a Cervical Spine Posterior Plate Versus Facet Wiring in a Laminectomy Model". En ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0104.

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Abstract Stability comparisons of cervical facet wiring and posterior cervical plating in a quasi-static and cyclic environment contain important clinical ramifications and this research addresses this issue. Decreases in motion at C4-C5 after undergoing bilateral laminectomy and subsequent stabilization indicated that plate decreases in motion were markedly higher than facet wiring decreases in all cases except cyclic extension. Posterior plates were superior in almost every loading mode tested, including the cyclic mode. The stabilized and cyclic results were only similar in extension between plates and wires. Screw torque decreases between pre- and post-fatigue plate measurements did not appear to affect specimen stability. Posterior plates appear to be biomechanically superior to facet wiring in cervical spine stabilization following laminectomy.

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Lim, Tae-Hong, Howard S. An, Young Do Koh y Linda M. McGrady. "A Biomechanical Comparison Between Modern Anterior Versus Posterior Plate Fixation of Unstable Cervical Spine Injuries". En ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0306.

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Abstract Unstable cervical spine injuries include flexion-distraction injuries with unilateral or bilateral facet dislocations and burst fracture of the vertebral body. These unstable injuries have been treated in various ways. For instance, various posterior fixation methods have been available, and particularly plating with lateral mass screws was proved to provide a rigid fixation. However, most cervical decompressions need to be performed anteriorly because the majority of compression is caused by either vertebral body retro-pulsion or herniated disc material (anterior structure). Anterior plating technique was recently introduced and employed for the surgical treatment of unstable injuries. Anterior plating is thought to offer an acceptable stability through a single surgical approach, but additional posterior fixation is frequently recommend to achieve a sufficient stability. There is a paucity of data on a direct biomechanical comparison of the stiffness provided by modern anterior, posterior, or combined plate-screw fixation in a human cadaveric cervical spine model. The purpose of this study was to compare the biomechanical characteristics of anterior vs posterior plating constructs and to evaluate the stiffness of a combined anterior-posterior fixation construct in a clinically simulated flexion-distraction injury and burst fracture models of the cervical spine.

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Goel, V. K., H. Kuroki, S. Holekamp, V. Pitka¨nen, S. Rengachary y N. A. Ebraheim. "Biomechanical Comparison of Two Atlantoaxial Arthrodeses in a Cadaveric Spine Model: Transarticular Screw Fixation Versus Screw and Rod Fixation". En ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32631.

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The causes of atlantoaxial instability include trauma, tumor, congenital malformation, or rheumatoid arthritis. Commonly available fixation techniques to stabilize the atlantoaxial complex are several posterior wiring procedures (Brooks fusion, Gallie fusion), transarticular screw procedure (Magerl technique), either alone or in combination. Wiring procedures are obviously easier to accomplish however these do not provide sufficient immobilization across the atlantoaxial complex1,3,4. On the other hand, although transarticular screw fixation (TSF) affords a much stiffer atlantoaxial arthrodesis than posterior wiring procedures. However, TSF has some drawbacks; for example the injury of vertebral artery. Furthermore, body habitus (obesity or thoracic kyphosis) may prevent from achieving the low angle needed for correct placement of screws between C1 and C2. Recently, a new technique of screw and rod fixation (SRF) that minimizes the risk of injury to the vertebral artery and allows intraoperative reduction has been reported2,6. The purpose of this study was to compare the biomechanical stability imparted to the C1 and C2 vertebrae by either TSF or SRF technique in a cadaver model.

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