Unusual sequelae of surgery in the superior oblique tendon sheath syndrome.

The superior oblique tendon sheath syndrome was first described by Brown (I950). The essential feature is a limitation of elevation in adduction caused by a short or inadequately mobile anterior segment of the superior oblique tendon and its sheath. Treatment of the condition is indicated if an abnormal head posture is necessary in order to maintain an adequate field of binocular single vision; if a manifest deviation has developed, but evidence of potential binocular functions remains; or if, in the apparent absence of binocular potential, a cosmetic defect can be improved. Those patients able to maintain an adequate field of binocular vision with a cosmetically satisfactory head posture should be kept under observation. The recognized treatment is first to demonstrate the limitation of elevation in adduction by the traction test under general anaesthesia; secondly to divide the superior oblique sheath and usually its tendon; and lastly to confirm by a second traction test that full passive movement has been obtained. After this procedure it is not uncommon to find that active elevation in adduction is still limited. Some surgeons prefer to combine division of the sheath only with resection of the ipsilateral inferior oblique (Nutt and Mein, I963). The present case is described because division of the right superior oblique tendon and sheath was followed by bilateral inferior oblique overaction, requiring bilateral inferior oblique recession. The patient also developed signs of alternating sursumduction, first demonstrated after the superior oblique surgery.