A Right-angle Siamese-twin Caliper for Greater Accuracy and Precision in Eye Muscle Surgery
In surgical recession of extraocular muscles for strabismus, failure to recess the muscle exactly perpendicular to the original muscle insertion can result in significant errors of recession and vertical transposition. An error as little as 6 degrees can reduce surgical success rates up to 13% and create a 1 mm vertical transposition as well. In addition, if such an oblique or tilted muscle re-insertion is created, an A or V pattern anisotropia can result.
To avoid these errors and their effects and to facilitate consistency in surgical technique for strabismus surgery, two straight Castroviejo calipers which have been joined In Siamese twin fashion, at a right angle along the fixed base leg of both calipers, to create a right-angle conjoined double caliper. It has proven very useful by insuring accurate and truly perpendicular eye muscle recessions and accurate vertical transpositions when indicated. It has improved both the speed and general precision of such surgery, and virtually eliminated technical problems of scleral suture placement.
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- ADDENDUM: At the time of presentation of this poster, it was brought to our attention that a similar instrument has been previously designed and reported by Emilio C. Campos, M.D. (AMA Archives of Ophthalmology 105(4): 579, April 1987).Google Scholar