Inferior Oblique Myectomy Versus Anterior and Nasal Transposition of Its Tendon for Treatment of Superior Oblique Muscle Palsy

Superior oblique palsy is one of the most common causes of vertical ocular muscle palsy. It may be congenital or acquired with over-elevation of the affected eye in primary position that increases in contralateral gaze and with ipsilateral head tilt . Torsional and vertical diplopia may occur resulting in compensatory head tilt .

Bilateral superior oblique palsy is approximately 29%-38% of cases of superior oblique palsy. It is a rare congenital or acquired ocular motility disorder. It can be symmetrical or asymmetrical .

Superior oblique palsy can be treated by different types of surgeries including superior oblique strengthening by tucking of its tendon, contralateral inferior rectus muscle recession, recession of ipsilateral superior rectus muscle or inferior oblique weakening by disinsertion , myectomy , recession and anterior transposition .

Superior oblique tucking is an efficient and safe procedure for treatment of superior oblique palsy with vertical deviation less than 15 prism diopter in the primary position and remarkable superior oblique under action. The superior oblique forced duction test is the most important for planning surgery .This procedure may cause iatrogenic post-operative Brown syndrome .

Recession of the ipsilateral superior rectus muscle reduces the upward force elevating the hypertropic eye. Recession of the contralateral inferior rectus muscle is another option that reduces the force shifting the contralateral eye downward to match the position of the other hypertropic eye due to superior oblique muscle palsy .