Impact of Superior Oblique Transposition on Primary Position Deviation, a Pattern and Intorsion in Third Nerve Palsy

ABSTRACT Purpose: To evaluate the role of superior oblique transposition on primary position alignment, A pattern, and intorsion in third nerve palsy. Methods: Ten patients with isolated, unilateral third nerve palsy were included in this prospective study. The patients were treated by conventional surgery on horizontal recti together with superior oblique transposition by Scott’s procedure in the paretic eye. Results: Pre-operative primary horizontal deviation was 60-80 PD (mean 70.00±7.45 PD). Pre-operative primary hypotropia was 15-22 PD (mean 18.80±2.48 PD). Mean A-pattern was 17.80±2.65 PD. All patients included in the study had some degree of objective torsion as measured by Guyton’s method. One patient had grade I objective intorsion, 2 had grade II, 6 had grade III, and 1 had grade IV objective intorsion. Primary position horizontal alignment (up to ±8 PD) was achieved in 9 patients. Primary position vertical alignment (up to ±8 PD) was achieved in all 10 patients. Only 2 of 10 patients had A-pattern of 10 PD, in the remaining 8 patients it was eliminated (P<0.05). Postoperatively, 5 patients had no objective intorsion and 5 had grade I intorsion, and none of the patients had hypertropia or paradoxical eye movements. Conclusion: Superior oblique transposition by Scott’s procedure along with conventional surgery on horizontal recti in third nerve palsy results in better horizontal and vertical alignment, and improves A-pattern and intorsion, thus leading to better binocular interaction.