TY - JOUR
T1 - Extraocular muscle insertion shift after disinsertion during strabismus surgery
AU - Honglertnapakul, Worawalun
AU - Capo, Hilda
AU - Cavuoto, Kara M.
AU - McKeown, Craig A.
N1 - Funding Information:
This study was supported by the NIH Center Core Grant [P30EY014801] from Research to Prevent Blindness. We wish to acknowledge Maja Kostic, MD, PhD and Haci U Celik, MD.
PY - 2020/4/2
Y1 - 2020/4/2
N2 - Purpose: To quantify the amount of insertion shift after disinsertion of the rectus muscles and identify factors that may influence the shift. Methods: Patients who underwent rectus muscle surgery between November 2018 and April 2019 were included. During surgery, the limbal-insertion distance (LID) distance was measured in millimeters with calipers from the limbus to the center of the insertion at the anterior border of the rectus muscle prior to and after disinsertion. The primary outcome was the shift of the rectus muscle insertion after disinsertion. This was calculated by subtracting the LID after disinsertion from the LID before disinsertion. The secondary outcome was the identification of preoperative and intraoperative factors that influenced insertion shift. Randomization was performed to select one rectus muscle per patient. Patients with a history of prior scleral buckle procedure, glaucoma drainage device, orbital wall fracture and strabismus surgery in the same rectus muscle were excluded. Results: 110 patients were included. The median (Q1, Q3) LID before disinsertion was shortest for the medial rectus muscle [5.0 (4.5, 6.0)], followed by lateral rectus muscle [6.0 (6.0, 7.0)] and inferior rectus muscle [6.0 (5.5, 7.0)]. The overall median (Q1, Q3) insertion shift was 1.0 (0.8, 1.0) mm (p < .001), which did not significantly differ between each rectus muscle subgroup (p = .158). Factors that influenced the amount of shift were moderate to severe restriction on forced duction testing (FDT) (B = 0.320, SE = 0.105, p = .003) and longer LID before disinsertion (B = 0.172, SE = 0.036, p < .001). Conclusions: We found a significant anterior insertion shift after disinsertion of rectus muscles. Moderate to severe restriction on FDT and longer LID before disinsertion can result in larger insertion shifts.
AB - Purpose: To quantify the amount of insertion shift after disinsertion of the rectus muscles and identify factors that may influence the shift. Methods: Patients who underwent rectus muscle surgery between November 2018 and April 2019 were included. During surgery, the limbal-insertion distance (LID) distance was measured in millimeters with calipers from the limbus to the center of the insertion at the anterior border of the rectus muscle prior to and after disinsertion. The primary outcome was the shift of the rectus muscle insertion after disinsertion. This was calculated by subtracting the LID after disinsertion from the LID before disinsertion. The secondary outcome was the identification of preoperative and intraoperative factors that influenced insertion shift. Randomization was performed to select one rectus muscle per patient. Patients with a history of prior scleral buckle procedure, glaucoma drainage device, orbital wall fracture and strabismus surgery in the same rectus muscle were excluded. Results: 110 patients were included. The median (Q1, Q3) LID before disinsertion was shortest for the medial rectus muscle [5.0 (4.5, 6.0)], followed by lateral rectus muscle [6.0 (6.0, 7.0)] and inferior rectus muscle [6.0 (5.5, 7.0)]. The overall median (Q1, Q3) insertion shift was 1.0 (0.8, 1.0) mm (p < .001), which did not significantly differ between each rectus muscle subgroup (p = .158). Factors that influenced the amount of shift were moderate to severe restriction on forced duction testing (FDT) (B = 0.320, SE = 0.105, p = .003) and longer LID before disinsertion (B = 0.172, SE = 0.036, p < .001). Conclusions: We found a significant anterior insertion shift after disinsertion of rectus muscles. Moderate to severe restriction on FDT and longer LID before disinsertion can result in larger insertion shifts.
KW - Limbal-insertion distance
KW - insertion shift
KW - rectus muscle insertion
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U2 - 10.1080/09273972.2020.1720746
DO - 10.1080/09273972.2020.1720746
M3 - Article
C2 - 32079447
AN - SCOPUS:85090105191
VL - 28
SP - 85
EP - 90
JO - Strabismus
JF - Strabismus
SN - 0927-3972
IS - 2
ER -