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Dose Effect and Stability of Postoperative Cyclodeviation After Adjustable Harada-Ito Surgery
Laura Liebermann1, David A Leske1, Sarah R Hatt1
1Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA.
American Journal of Ophthalmology
|September 7, 2018
Summary
Adjustable Harada-Ito surgery for superior oblique tendon issues shows a dose response of 1.3 degrees per millimeter. However, the effect of this cyclodeviation surgery diminishes over time, suggesting a target of 7 degrees incyclodeviation is reasonable.
Area of Science:
- Ophthalmology
- Strabismus Surgery
- Oculomotor Function
Background:
- Superior oblique palsy can lead to debilitating cyclodeviation.
- The Harada-Ito procedure is a surgical option to correct these deviations.
- Adjustable techniques offer intraoperative flexibility but require understanding of dose-response and stability.
Purpose of the Study:
- To determine the dose-response relationship of adjustable Harada-Ito surgery.
- To evaluate the postoperative stability of cyclodeviation correction achieved with this technique.
Main Methods:
- A retrospective cohort study of 20 patients undergoing unilateral adjustable Harada-Ito surgery.
- Surgical dose quantified by resection, advancement, and adjustment.
- Cyclodeviation measured preoperatively and postoperatively using double Maddox rods.
Main Results:
- A dose effect of 1.3 degrees of incyclo effect per millimeter of surgical adjustment was observed (rs = 0.52, P = .019).
- Initial incyclodeviation ranged from 7 to 20 degrees.
- Mean unwinding of 3.6 degrees occurred by day 1, and 6.5 degrees by 6 weeks post-surgery.
Conclusions:
- Adjustable Harada-Ito surgery demonstrates a predictable dose response but with significant regression over time.
- An initial target of 7 degrees incyclodeviation is suggested for optimal outcomes.
- Long-term stability requires further investigation due to progressive unwinding.
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