Comparison of augmented and nonaugmented modified Knapp procedure for the treatment of nonrestrictive double elevator...

To compare surgical results of augmented and nonaugmented modified Knapp procedure, for the treatment of nonrestrictive double elevator palsies (DEP).

The medical records of patients with congenital DEP were reviewed retrospectively. Patients were divided into three treatment groups: standard transposition (group A), Foster transposition (group B), and resection transposition (group C). Pre- and postoperative vertical deviation in primary position, ocular motility, and binocular vision were compared.

Thirty patients were enrolled. The pre- and postoperative deviations in group A were 34.7^Δ ± 8.6^Δ and 6.5^Δ ± 6.5^Δ; in group B, 38.6^Δ ± 14.6^Δ and 5.7^Δ ± 9.3^Δ; and in group C, 43.1^Δ ± 10.3^Δ and 8.5^Δ ± 6.1^Δ. The corrected vertical deviation of group B (32.9^Δ ± 5.7^Δ) and group C (34.6^Δ ± 5.0^Δ) were greater than that of group A (28.1^Δ ± 3.6^Δ; P = 0.03, 0.002). The pre- and postoperative measures of upgaze in group A were -3.7 and -1.8; in group B, -4.0 and -1.3; and in group C, -3.6 and -2.0. The average improved upgaze in group B (2.6 ± 0.5) was statistically significantly better than that in group A (1.9 ± 0.6) and group C (1.5 ± 0.5; P = 0.03, 0.002). There was no significant difference in the surgical effect on downgaze in three groups (P > 0.05). The surgical outcome was satisfactory in 19 (63.3%) patients with preoperative vertical devation of ≤40^Δ.

All transpositions are reasonably effective in treating vertical deviations of <35^Δ without obviously limiting downgaze in DEP. Augmented procedures could correct greater vertical deviation of 30^Δ-40^Δ. The Foster transposition demonstrates the strongest effect in improving upgaze.