Bilateral Lateral Rectus Recession for the Treatment of Recurrent Exotropia after Bilateral Medial Rectus Resection

2018 ◽  
Vol 61 (2) ◽  
pp. 120-124
Author(s):  
Xi Wang ◽  
Xiaohang Chen ◽  
Longqian Liu
Keyword(s):  
Lateral Rectus ◽  
Medial Rectus ◽  
Recurrent Exotropia

scholarly journals Surgical Effect of Unilateral Medial Rectus Resection According to Tendon Width in Recurrent Exotropia

2018 ◽  
Author(s):  
Suk-Gyu Ha ◽  
Seung-Hyun Kim
Keyword(s):  
General Anesthesia ◽  
Dose Response ◽  
Lateral Rectus ◽  
Medial Rectus ◽  
Recurrent Exotropia ◽  
Angle Of Deviation

Abstract Background To investigate the dose response according to tendon width of the medial rectus in patients with recurrent exotropia who underwent unilateral medial rectus resection. Methods Patients with basic recurrent exotropia after bilateral lateral rectus recession were included. All patients underwent unilateral medial rectus resection according to the preoperative angle of deviation. Under general anesthesia, the tendon width of the medial rectus in the operated eye was measured. The patients were divided into 2 groups (narrow and wide) according to the median value of the tendon width of the medial rectus. The angle of deviation at postoperative day 1 was measured. The dose response was calculated based on the amount of correction and resection. Results This study included 38 patients. Age and preoperative angle of deviation were 11.0 ± 3.0 years (range, 6 – 19 years) and 21.3 ± 3.2 prism diopters (PD; range, 15 – 25 PD), respectively. Tendon width of the medial rectus was 7.6 ± 0.7 mm (range, 6.0 - 8.5 mm) and the median value of tendon width was 7.5 mm. The dose response was 4.6 ± 0.8 PD/mm (range, 2.4 - 5.6 PD/mm). The dose response was significantly greater in the wide than in the narrow tendon width group (p < 0.001). Tendon width of the medial rectus was significantly correlated with age, the preoperative angle of deviation and surgical dose response (all, p < 0.05). Conclusion The tendon width of the medial rectus could be a predictor for estimating the surgical dose response when considering unilateral medial rectus resection in patients with the moderate angle of recurrent exotropia.

Outcomes of bilateral lateral rectus recession in treatment of recurrent exotropia after bilateral medial rectus resection

2018 ◽  
Vol 29 (4) ◽  
pp. 402-405
Author(s):  
Amr Elkamshoushy ◽  
Michael A Langue
Keyword(s):  
Chart Review ◽  
Rectus Muscle ◽  
Retrospective Chart Review ◽  
Lateral Rectus ◽  
Medial Rectus ◽  
Primary Surgery ◽  
Lateral Rectus Muscle ◽  
Recurrent Exotropia ◽  
Large Primary

Purpose: To report the results of bilateral lateral rectus muscle recession for recurrent exotropia in cases where the primary surgery was a bilateral medial rectus resection. Methods: Retrospective chart review of 15 subjects who completed 6 months of follow-up. Data collected included patients’ demographics and pre- and post-operative measurements of ocular alignment and motility. Surgical nomogram used was the same nomogram we use for primary cases of exotropia. Results: At 6-month follow-up, 73.3% of cases had a successful surgical outcome (defined as 8 PD of esotropia to 10 PD of exotropia). In addition, recession of lateral rectus muscles against the previously resected medial recti did not result in a significant increase in the limitation of abduction. Conclusion: Bilateral lateral rectus recession using standard surgical tables is a safe and effective method for treating recurrent exotropia following bilateral medial rectus resection. Even large primary resections up to 12 mm do not seem to affect the results of bilateral lateral rectus recession.

Contractile differences between muscle units in the medial rectus and lateral rectus muscles in the cat

1986 ◽  
Vol 56 (1) ◽  
pp. 50-62 ◽  
Author(s):  
M. A. Meredith ◽  
S. J. Goldberg
Keyword(s):  
Horizontal Plane ◽  
Complex Interaction ◽  
Contractile Properties ◽  
The Other ◽  
Lateral Rectus ◽  
Medial Rectus ◽  
Types Of Muscle Fibers ◽  
Horizontal Gaze ◽  
Afferent Inputs ◽  
Central Factors

Conjugate eye movements in the horizontal plane are accomplished by the coactivation of the medial rectus (MR) muscle of one orbit and the lateral rectus (LR) muscle of the other. While control of these excursions has been thought to be effected by identical inputs to these muscles, recent studies have demonstrated that MR motoneurons receive different inputs than LR motoneurons. This raises the question of whether the character of the muscles they control are different. The present study evaluated the contractile properties of MR and LR muscle units in the cat. Based on the mechanical aspects of their contractile properties, only two physiological types of muscle units were identified within the MR and LR muscles: twitch and non-twitch muscle units. Twitch muscle units represented over 90% of the units sampled in each muscle. Significant differences in the rate-related and the tension-related contractile properties were demonstrated between MR and LR twitch muscle units. MR muscle units exhibited significantly faster twitch contractions than did LR units. The rate of stimulation at which MR units exhibited fused tetany was significantly higher than for LR units, although units from both muscles demonstrated similar rates of rise of tension at fusion. The rate of rise of tension was closely correlated to tension production (twitch and tetanus) in each muscle. However, MR muscle units demonstrated significantly weaker maximum tetanic tensions and lower tetanus-to-twitch ratios than LR units. These data indicate that while similar physiological types of muscle fibers are present within the MR and LR, MR muscle units are adapted for faster rate-related properties, whereas LR units are adapted for greater tetanic tensions. These distinctions between MR and LR muscle units, coupled with differences between the afferent inputs to their respective motoneurons, suggest that the preservation of conjugacy during horizontal gaze shifts may require a complex interaction of peripheral and central factors.

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