Passive limitation of adduction after Cuppers's 'Fadenoperation' on medial recti.

Abstract

SUMMARY In 40 eyes of 20 esotropic subjects in which a 'Fadenoperation' was performed on the medial recti we measured the resistance to ocular rotation in adduction before and after the operation. The difference between the two sets of force measurements demonstrates that the Fadenoperation on medial recti produces a mechanical restriction to adduction which can explain the effect of the surgical procedure on the strabismic deviation.In 1974 Ctppers described the well known surgical procedure which he named 'Fadenoperation'.' The effect of the operation was at first attributed solely to the reduction of the tangential component of the muscle force produced by the posterior fixation.'2 Later it was pointed out3 that several different mechanisms could interact and concur to produce the surgical effect:(1) the reduction of the rotational component of the force generated by the muscle;(2) the exclusion from activity of a contingent of the muscle fibres; (3) a stretching of the muscle owing to the fact that the scleral fixation increases the distance between the origin and the true insertion of the muscle if the true insertion remains in its original position; (4) a slack in the muscle fibres posterior to the fixation suture which occurs when the tightening of the suture is made while the muscle is stretched to provide adequate exposure4;(5) a mechanical restriction to ocular rotation in the field of action of the operated muscle"6 produced by the connective tissue structures, which endeavour to maintain the physiological course of the muscle,3 or by a 'reverse leash' mechanism.7 All these hypothetical effects were derived from a theoretical analysis of the new mechanical situation Correspondence to G P Paliaga, MD, Centro per lo Strabismo, Via Masia 97,

Medial rectus Faden operations with or without recession for partially accommodative esotropia associated with a high accommodative convergence to accommodation ratio

“…They explained that the procedure's effect was lost over time 11. Similarly, a decrease in the effects of posterior fixation over time has been reported by Paliaga et al 22 The constant stress on the suture created by MR contraction, coupled with soft tissue remodelling and wound healing after surgery, may diminish the effects of posterior fixation over time 22 23. In this study, the postoperative near deviation was not stable for all patients over the duration of the follow-up period, but we did not observe a scar between the muscle and the sclera during the secondary surgery of the Faden operations.…”

Efficacy of posterior fixation suture augmented with talc or doxycycline

“…Suture-related problems such as inadequate posterior placement of the suture, a loose suture, or sutures that migrate forward can cause this problem [2,8]. A decrease in the effect of the procedure over time has been reported [3]. We suppose that the constant stress on the suture created by extraocular muscle contraction, coupled with soft tissue remodeling, probably diminishes the effect of the procedure over time.…”

“…Although its mechanism of action is controversial [2][3][4][5], limited movement toward the operatedon muscle is a unique property of the procedure. Due to this property, this procedure has some special applications, including incomitant strabismus, or dissociated vertical deviation [2,6].…”

“…However, limitations include the technical difficulty of approaching behind the equator of the globe, a risk of scleral perforation, vortex vein injury, and a weaker effect than expected. In addition, this operation tends to lose its initial effect as time passes [2,3,7,8].…”

La myopexie rétroéquatoriale oblique

“…Cette action est atténuée ou contrebalancée par la force des structures de soutien (capsule de Tenon,membrane inter-musculaire), dont la fonction est de maintenir le muscle dans sa trajectoire originelle (9). Enfin, un contingent de fibres musculaires est purement et simplement privé de sa fonction normale (13).…”