Evaluation of the Strengthening Effect of the Superior Oblique Tuck Procedure
Grace Wang, MD, PhD; Shawn S. Gappy, MD; Chris Gappy, MD; Steven Archer, MD
Kellogg Eye Center – University of Michigan Health System
Ann Arbor, MI
Introduction: It is held in some quarters that tightening procedures (resection, plication, tuck) do not actually “strengthen” a muscle but only affect its passive properties. In this study we evaluate whether this is the case for superior oblique (SO) tuck procedures.
Methods: The surgical database at the Kellogg Eye Center was searched for cases of superior oblique palsy that underwent a SO tuck procedure from 1998-2014 and had pre- and post-operative measurements of the vertical deviation in primary gaze and in the field of action of the superior oblique muscle.
Results: Forty-two patients met study criteria. The mean change in vertical deviation was 7.1PD ± 4.6PD in primary gaze and 15.4PD ± 9.0PD in the field of action of the superior oblique muscle (P < 0.0001, paired t-test).
Discussion: If SO tuck acts only by affecting the elastic or restrictive properties of the muscle, it should produce less change of vertical deviation in the field of action of the SO muscle than in primary gaze. Instead we found that SO tuck produces, on average, roughly twice as much correction in the field of action of the SO muscle.
Conclusion: The SO tuck procedure improves vertical deviations, at least in part, by strengthening active contraction force of the superior oblique muscle.
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