The Outcome of One-to-Four Muscle Surgery by Intraoperative Relaxed Muscle Positioning with Adjustable Suture Technique in Thyroid Eye Disease

Apatsa Lekskul,1 Phantaraporn Tangtammaruk,1,2 Wadakarn Wuthisiri1 1Department of Ophthalmology, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand; 2Metta Pracharak Hospital, Nakhon Pathom, 73210, ThailandCorrespondence: Wadakarn WuthisiriDepartment of Ophthalmology, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, ThailandTel +66 2-201-2729Fax +66 2-201-1516Email wuthisiri@gmail.comPurpose: To identify the outcome of one-to-four muscle surgery by intraoperative relaxed muscle positioning with adjustable suture technique for the treatment of thyroid eye disease.Methods: Ninety patients diagnosed with thyroid eye disease who underwent intraoperative relaxed muscle positioning with adjustable suture technique at Ramathibodi Hospital from January 1, 2015 through December 31, 2020 were included in this retrospective study. The patient demographic data were evaluated. Pre- and post-operative ocular alignment and diplopia status were measured after a follow-up period of at least 6 months. Successful outcomes were categorized into two parts: motor outcome and sensory outcome. Successful motor outcome was defined as vertical deviation equal to 4 prism diopters or less and horizontal deviation equal to 10 prism diopters or less in primary position. Successful sensory outcome was defined as the absence of diplopia in primary position.Results: Ninety patients were included in this study, and the mean age of strabismic surgery was 56.6 ± 10.1 years old. Thirty-nine patients had a history of orbital decompression surgery. Mean follow-up time was 33.7 ± 11.8 months. The success of motor and sensory outcomes exhibited a decrease from one-to-four muscle surgery. Motor success decreased from one-muscle to four-muscle surgery (84.62%, 81.58%, 75.00%, and 64.29%) and sensory success similarly decreased (84.62%, 84.21%, 75.00%, and 78.57%). However, the comparative outcomes of motor success and sensory success were not statistically different among groups (p = 0.58 and 0.84). Lower lid retractions were found in 12 patients (13.33%).Conclusion: Intraoperative relaxed muscle positioning technique might be a successful option for the correction of thyroid eye disease-associated strabismus. This technique may be done with one-to-four muscle surgery, which yields success in both motor and sensory outcomes.Keywords: thyroid eye disease, one-to-four strabismus surgery, intraoperative relaxed muscle positioning, restrictive strabismus, adjustable suture technique