Outcomes of the intraoperative relaxed muscle positioning technique in strabismus surgery for thyroid eye disease

The intraoperative relaxed muscle positioning (IRMP) technique for strabismus surgery in thyroid eye disease (TED) involves recessing muscles' insertions to positions where they rest without tension. We evaluate the long-term outcomes of patients who underwent surgery using this technique.

The medical records of patients with TED and diplopia who underwent strabismus surgery with IRMP between 1999 and 2021 were reviewed retrospectively. Excellent outcomes were defined as no diplopia in primary and reading gazes without the use of prisms; good outcomes, as residual deviation of <10^Δ with diplopia in primary and reading gazes. Good or excellent outcomes were considered successes. Poor outcomes were defined as residual deviation >10^Δ with diplopia in primary and reading gazes or the inability of patients to tolerate prismatic correction.

A total of 129 patients were followed for an average of 4.24 ± 5.13 years (longest follow-up 20 years): 96 (73.6%) underwent a single surgery, and 33 (26.4%) underwent additional interventions. Seven of these had been planned as staged procedures, and all were successful. Five patients experienced disease reactivation and underwent additional surgery, with successful outcomes in 4 (80%). Of the remaining 21 patients, 6 underwent a third procedure, and a single patient underwent a fourth. Overall, 93.6% of patients had a successful outcome: 77.5% excellent and 16.3% good.

In our study cohort, the IRMP approach resulted in durable relief from large-angle strabismus and diplopia in a large majority of patients.