A standardized recession of the inferior oblique extraocular muscle - a safe and self-grading surgical procedure for trochlear nerve palsy: a 10-year material

Purpose To evaluate the results of surgical treatment in a large group of patients with trochlear nerve palsy, with emphasis on the self-grading effect of a standardized recession of the ipsilateral inferior oblique muscle. Methods All patients who underwent first-time surgery for trochlear nerve palsy in the period 2005-2014 in our department (n = 114) were retrospectively evaluated regarding pre- and postoperative data, surgical procedure, and the need for reoperations. Mean follow-up time was 8.5 +/- 13.8 months. Results Among the 114 patients, 73 (64.0%) had a congenital palsy, 31 (27.2%) an acquired palsy, while in 10 cases (8.8%) the type of palsy was uncertain. A standardized recession of the ipsilateral inferior oblique muscle with reattachment at the lateral border of the inferior rectus muscle was carried out in 97.3% of the congenital palsies and in 80.5% of the acquired/uncertain group. In the total patient material, further surgery was needed in 15.8%. Among the patients who underwent a single standardized recession of the inferior oblique muscle, a significant correlation between preoperative vertical angle of deviation and the postoperative change in deviation was demonstrated (correlation coefficient -0.70, p < 0.001), confirming the self-grading nature of this procedure. Subjectively, 97.1% in the congenital and 91.4% in the acquired/uncertain group reported complete/near complete resolution or significant improvement of their symptoms at the final control examination. Conclusion In the majority of patients with trochlear nerve palsy, a favourable outcome may be achieved after a single, standardized recession of the ipsilateral inferior oblique muscle.