Increased Extraocular Muscle Strength with Direct Injection of Insulin-like Growth Factor-I

Anderson, Brian C.; Christiansen, Stephen P.; Grandt, S.T.; Grange, Robert W.; McLoon, Linda K.

doi:10.1167/iovs.05-1416

Cited by 50 publications

(63 citation statements)

References 28 publications

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“…Yet, these methods are advantageous because the muscle's origin is preserved, its orientation is largely conserved, and an intact blood supply maintains the viability of the muscle (Bach-yRita and Ito, 1966;Barmack et al, 1971;Hanson and Lennerstrand, 1977;Shall and Goldberg, 1992;Dimitrova et al, 2002;Shall et al, 2003). The relative ease of in vitro preparations for the determination of extraocular muscle force is reflected by their extensive use (Close and Luff, 1974;Luff, 1981;Chiarandini, 1980Chiarandini, , 1987Asmussen and Gaunitz, 1981;Jacoby et al, 1989;Chen and von Bartheld, 2004;McLoon et al, 2006;Anderson et al, 2006). While in vitro methods have the advantage of being technically less demanding and do not require general anesthesia, they may not be optimal for obtaining accurate contractile measurements of extraocular muscle.…”

Section: Introductionmentioning

confidence: 99%

Measurement of contractile force of skeletal and extraocular muscles: Effects of blood supply, muscle size and in situ or in vitro preparation

Croes

Bartheld

2007

Journal of Neuroscience Methods

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Contractile forces can be measured in situ and in vitro. To maintain metabolic viability with sufficient diffusion of oxygen, established guidelines for in vitro skeletal muscle preparations recommend use of relatively thin muscles (≤1.25 mm thick). Nevertheless, forces of thin extraocular muscles vary substantially between studies. Here, we examined parameters that affect force measurements of in situ and in vitro preparations, including blood supply, nerve stimulation, direct muscle stimulation, muscle size, oxygenated or non-oxygenated buffer solutions, and the time after interruption of vascular circulation. We found that the absolute forces of extraocular muscle are substantially lower when examined in vitro. In vitro preparation of 0.58 mm thick extraocular muscle from 3-week old birds underestimated contractile function, but not of thinner (0.33 mm) muscle from 2-day old birds. Our study shows that the effective criteria for functional viability, tested in vitro, differ between extraocular and other skeletal muscle. We conclude that contractile force of extraocular muscles will be underestimated by between 10 and 80%, when measurements are made after cessation of blood supply (at 5 -40 min). The mechanisms responsible for the declining values for force measurements are discussed, and we make specific recommendations for obtaining valid measurements of contractile force.

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Section: Introductionmentioning

confidence: 99%

Measurement of contractile force of skeletal and extraocular muscles: Effects of blood supply, muscle size and in situ or in vitro preparation

Croes

Bartheld

2007

Journal of Neuroscience Methods

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“…Em função das inúmeras variáveis que podem interferir nos resultados pós-operatórios de pacientes submetidos a cirurgias de correção de estrabismo, novos estudos são necessários no sentido de melhor controlar desvios pós-operatórios a curto e longo prazo, como por exemplo o uso de forças magnéticas (1) ou o uso de fatores de crescimento (29) .…”

Section: Discussionunclassified

Variações no posicionamento dos eixos visuais em pacientes submetidos a cirurgias de estrabismo

Brum¹,

Antunes-Foschini²,

Abbud³

et al. 2011

Arq. Bras. Oftalmol.

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RESUMOObjetivos: Determinar as variações no ângulo de posicionamento ocular pós-operatório em pacientes submetidos a cirurgias para correção de estrabismo e identificar possíveis fatores de risco associados a tal ocorrência. Métodos: Foi realizado estudo retrospectivo de 819 pacientes portadores de estrabismo submetidos à cirurgia para correção do desvio ocular entre janeiro de 1995 ) among the total of studied patients was 33.5% (274 patients). In those patients, a higher frequency was found in the exotropic direction (178 patients or 65.0%) than in the esotropic direction (96 patients or 35,0%), and this difference was statistically significant (chi-square test; p<0.001). Conclusions: Eye positioning instability can occur over time in patients who underwent strabismus surgery. This incident reinforces the need for the development of alternative therapies in order to INTRODUÇÃOA correção cirúrgica é a principal forma de tratamento para os pacientes portadores de desvios oculares. As técnicas cirúr-gicas empregadas atuam nos músculos oculares externos (MOEs) a fim de restaurar a posição normal dos olhos. Na maioria das vezes, visa modificações nos MOEs, debilitando-os, fortalecendo-os ou alterando a orientação do seu plano de ação. Algumas vezes, é necessário atuar sobre as fáscias ou a conjuntiva, para eliminar restrições mecânicas à movimentação ocular (1) .É de conhecimento dos oftalmologistas que, no seguimento pós-operatório de cirurgias de estrabismo, alguns pacientes perdem a estabilidade do alinhamento ocular com o passar do tempo a despeito de um resultado cirúrgico satisfatório no pós-operatório inicial.Alguns estudos apontam que a taxa de reoperações em pacientes submetidos à cirurgia para correção de esotropia (ET), por exemplo, pode chegar a quase 30% (2)(3)(4)(5) com incidências ainda mais altas em estudos com seguimento mais longo (6)(7)(8)(9)(10)(11) . No caso das exotropias, estudos demonstram taxas de insucesso no alinhamento ocular entre 27% e 86% (12)(13)(14)(15)(16)(17) . O estudo das variações no ângulo de posicionamento dos eixos visuais em pacientes que foram submetidos a cirurgias de estrabismo é de suma importância no entendimento de possíveis fatores de risco relacionados a tal ocorrência e poderá auxiliar no desenvolvimento de abordagens terapêuticas que visem prevenir tal ocorrência.Assim, o presente estudo busca entender melhor possíveis fatores associados (tipo de desvio, idade do paciente, magnitude do desvio) à instabilidade no posicionamento ocular no pós-operatório de alguns pacientes submetidos a cirurgias de estrabismo. MÉTODOSForam avaliados todos os prontuários de pacientes portadores de estrabismo submetidos a cirurgias para correção do desvio

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“…These medications may promote changes in muscle biomechanics not attainable with surgery (4) . These changes include modulation of muscle force without permanently changing the muscle insertion on the eye (5) . Bupivacaine is an anesthetic drug that has been used in peri bulbar and retrobulbar anesthesia for a long time and presents few complications (6) .…”

Section: Introductionmentioning

confidence: 99%

Bupivacaine and botulinum toxin to treat comitant strabismus

Höpker¹,

Zaupa²,

Filho³

et al. 2012

Arq. Bras. Oftalmol.

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Purpose: To evaluate the change in ocular motility and muscle thickness measured with ultrasonography after intramuscular injection of bupivacaine and botulinum toxin A. Methods: Eight patients (five female) were enrolled to measure ocular motility prior and 1, 7, 30 and 180 days after one injection of 2 ml of 1.5% bupivacaine and 2.5 U of botulinum toxin A in agonist and antagonist muscles, respectively, of eight amblyopic eyes. Muscle thickness was measured prior and on days 1, 7 and 30 after injection using 10MHz ultrasonography (eyelid technique). Results: Mean change in alignment was 10 prism diopters after 180 days (n=6). An average increase of 1.01 mm in muscle thickness was observed after 30 days of bupivacaine injection and 0.28 mm increase was observed after botulinum toxin A injection, as measured by ultrasonography. Lateral rectus muscles injected with bupivacaine had a mean increase of 1.5 mm in muscle thickness. Conclusion: In this study, a change in ocular motility was observed after 180 days of intramuscular injection of bupivacaine and botulinum toxin in horizontal extraocular muscles. Overall, there was an increase of muscle thickness in both botulinum toxinum A and bupivacaine injected muscles after 30 days of injection when measured by ultrasonography. This change was more pronounced on lateral rectus muscles after bupivacaine injection.

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Increased Extraocular Muscle Strength with Direct Injection of Insulin-like Growth Factor-I

Abstract: Direct muscular injection of IGF-I effectively increases EOM force generation without the potential biomechanical hazards of surgery such as permanently altered muscle length or insertional position on the globe.

Cited by 50 publications

References 28 publications

Measurement of contractile force of skeletal and extraocular muscles: Effects of blood supply, muscle size and in situ or in vitro preparation

Measurement of contractile force of skeletal and extraocular muscles: Effects of blood supply, muscle size and in situ or in vitro preparation

Variações no posicionamento dos eixos visuais em pacientes submetidos a cirurgias de estrabismo

Bupivacaine and botulinum toxin to treat comitant strabismus

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