Graded superior oblique tendon suture lengthening: A novel procedure

Purpose: Literature regarding different superior oblique (SO) weakening procedures showed variable results. Here, we aim to evaluate the effect of a novel superior oblique tendon suture lengthening (SOSL) procedure on weakening of SO in patients with A-pattern exotropia associated with dissociated vertical deviation and SO overaction (triad exotropia). Methods: The medical records of triad exotropia patients who underwent SOSL or SO tenotomy were reviewed. Surgical results of SOSL procedure mainly regarding the correction of A pattern, SO overaction, and fundus intorsion were analyzed and compared with those of SO tenotomy procedure. Results: SOSL demonstrated comparable efficacy in correction of A pattern (20.2(o) +/- 10.7(o) vs 29.2(o) +/- 16.1(o), p = 0.172), normalization of SO overaction (1.9 +/- 0.9 vs 2.4 +/- 1.5, p = 0.349), and conversion of fundus intorsion (11.1 degrees +/- 7.0 degrees vs 11.3 degrees +/- 4.4 degrees, p = 0.691) as SO tenotomy. Moreover, the success rate of A pattern collapse was significantly higher in the SOSL group than in the SO tenotomy group (86% vs 40%, p = 0.028). None of the patients in the SOSL group, but two in the SO tenotomy group, presented SO palsy postoperatively. In the SOSL group, the corrected magnitude of SO overaction strongly correlated with the dosage of suture lengthening (p < 0.001). Conclusion: SOSL procedure could effectively eliminate the clinical manifestations associated with SO overaction. The graded dosage of SOSL leads to more controllable and predictable results compared to SO tenotomy, which makes SOSL a good alternative choice for SO weakening.

Automated summary

The study shows that the SOSL procedure has comparable efficacy to SO tenotomy in correcting A pattern, normalizing SO overaction, and converting fundus intorsion, with a significantly higher success rate in A pattern collapse. The SOSL group did not experience SO palsy postoperatively, and the degree of correction of SO overaction strongly correlated with the suture lengthening dosage.