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[Results of surgical treatment of Stilling-Türk-Duane retraction syndrome].

BACKGROUND
The typical signs of the retraction syndrome (Stilling-Türk-Duane) are abnormal head posture, marked limitation of abduction, slight limitation of adduction and convergence, which are always accompanied by retraction of the globe, narrowing of the palpebral fissure, vertical deviation and increased intraocular pressure upon adduction. All signs are explicable by the co-contraction of the horizontal muscles or the failing relaxation of the lateral rectus muscle. Abnormal synergistic innervation occurs when in aplasia of the abducens nerve the lateral rectus muscle receives abnormal innervation by branches of the oculomotor nerve, which may also be accompanied by fibrosis of those parts of the muscle that are not innervated. This pathogenesis gives reason for the variety of signs and reduces the value of all classifications defined by electromyography. It seems more sensible to classify the retraction syndrome with respect to the direction of the head turn.


PATIENTS AND METHODS
According to this classification, the left-sided retraction syndrome with head turn in adduction made up the largest, typical group (58%) in our study (n = 82). All other groups represented less than 12%. The main goal of surgical therapy was the elimination of the abnormal head turn, the vertical deviation and the retraction. Based on the pathogenesis, only recessions of one or both horizontal muscles were performed and strengthening procedures were avoided.


RESULTS
Concerning the horizontal and vertical deviation and the head posture, the surgical results of this procedure were satisfactory. Preoperatively less than 10% in all groups showed a deviation at distance of 5 degrees and less, whereas 6 month after surgery this small angle was obtained in over 60% in all groups. While preoperatively less than 20% in all groups had a head turn of 10 degrees and under at distance fixation, 6 months after surgery this was demonstrated in over 70% of all our cases.


CONCLUSION
The main goal of surgery is the reduction of the abnormal head posture, the retraction with narrowing of the palpebral fissure and the vertical deviation. Only recessions of one or both horizontal muscles can achieve the necessary mechanical relief. In cases with marked retraction one must avoid strengthening procedures.