[Surgical treatment of eye muscle palsies (author's transl)]

The surgical treatment of an eye muscle palsy is indicated at the end stage of all possible conservative therapeutic measures. If after an interval of 8 to 12 months an eye muscle palsy manifests no change of pattern, the indication for surgical treatment is given, provided the pathologic process causing the palsy is no longer active. Of great importance for the evaluation of surgery are the forced duction test, measurement of saccadic velocity and electromyography. The aim of the surgical intervention is to eliminate diplopia and restore parallelism of the visual axes if possible with every line of vision, but above all with the largest possible visual field in the primary position and in downwards gaze. Any eye muscle palsy produces an overaction of the homolateral antagonist, an overfunction of the contralateral synergist and a secondary inhibition of the contralateral antagonist. Theoretically four surgical possibilities would result from these conditions. However, in practice the choice is reduced to weakening (recession, faden-operation) of the homolateral antagonist or the contralateral synergist or possibly both and to strengthening (resection, tucking) of the primary paretic muscle. Not infrequently, the surgical intervention has to be performed in different steps on different muscles of both eyes. In cases of total palsies muscles transposition or transplantation procedures (Hummelsheim-O'Connor, Jensen etc.) must be considered. A promising new method of restoring innervation to a paralyzed muscle is muscular neurotization (implantation of the inferior oblique muscle into the paralyzed denervated external rectus muscle in cases of abducens nerve paralysis).