Two cases of acquired bilateral trochlea nerve palsy treated by simultaneous inferior rectus muscle nasal transposition and inferior oblique muscle myectomy

PURPOSE: To report two cases of acquired bilateral trochlea nerve palsy with large torsional deviation successfully treated by simultaneous bilateral inferior rectus muscle (IR) nasal transposition and inferior oblique muscle (IO) myectomy. OBSERVATIONS: Case 1 was of a 54-year-old man with torsional diplopia after a traffic accident. He showed 32° and 38° excyclotorsion in the primary and downward gazes, respectively. Case 2 was of a 56-year-old woman with torsional diplopia after a brain tumor operation. She showed 25° and 33° excyclotorsion in the primary and downward gazes, respectively. We simultaneously performed bilateral IR nasal transposition and IO myectomy in these two cases. Postoperatively, case 1 presented with improved excyclotorsion, with 2° and 7° excyclotorsion in the primary and downward gazes, respectively; case 2 similarly presented with improved excyclotorsion, with 4° and 12° excyclotorsion in the primary and downward gazes, respectively. CONCLUSIONS AND IMPORTANCE: Simultaneous bilateral IR nasal transposition and IO myectomy are effective for treating large-angle torsional deviations, especially in downward gaze, requiring only one operation. A new surgical approach is suggested for the successful treatment of large torsional deviations, requiring only one operation.