Operative procedures in cases of disinserted or missing superior oblique tendons

Introduction: If the surgeon cannot find the tendon of the superior oblique muscle in the right place, he has to change his operative plans intraopera tively. Different procedures are recommended: reinsertion of the superior o blique in the right place, recession of the inferior oblique muscle, and op erations on the vertical muscles of the same or the yoke eye. No quantitati ve recommendations on the surgical amount are mentioned in the literature. Methods: Ten patients with different forms of aberrant tendons are presente d, four patients with bilateral inferior oblique overaction and superior ob lique underaction, and six patients with unilateral strabismus sursoadducto rius. The pre-, intra- and postoperative findings are demonstrated. Results: In cases of mild disinsertions (Helveston classes 1 and 2) the sup erior oblique tendon was shortened using the normal amount in one or two mu scle procedures. If the superior tendon did not reach the sclera (Helveston classes 3 and 4), an operation on the superior oblique alone had not suffi ciently corrected the long-term deviations. In cases where both oblique mus cles are being operated on, the immediate postoperative effect was slight o vercorrection, but the long-lasting effect was good. In only one case did t he inferior oblique have to be reinserted in its original place because of long-lasting overcorrection of cyclotropia after the two-muscle procedure. Conclusions: An "absent" superior oblique tendon can often be found in the superior nasal part of the orbit near the superior rectus muscle. Reinserti on of the tendon in its physiological place (crossing over the superior rec tus muscle) will correct smaller amounts of vertical deviation in adduction only. If the vertical deviation exceeds 12 degrees in adduction, the opera tion on both oblique muscles can always ameliorate the ocular motility. Onl y in rare cases can a second operation become necessary.