Midoperative Forced Duction Test as a Guide to Titrate the Surgery for Consecutive Exotropia

Abstract

This is a retrospective study of the outcome of all consecutive exotropia surgery performed between the years 1999 and 2007. Excluded were cases of slipped muscles, muscle transpositions, and concurrent cyclovertical procedures. A total of 135 patients of mean age 40 years (range 6-72) were operated with a mean preoperative angle of deviation -40Delta (range -12 to -90). Five were treated with fixed sutures and the rest with adjustables. The surgery included preplanned lateral rectus recessions of mean 6 mm (range 2-9) and maximal possible medial rectus advancements with or without resections of mean 5.6 mm (range 2-11), intraoperatively adjusted to give a resistance of +1 to +2 for abduction on forced duction test (FDT). Adjustable suture patients were seen 4 to 6 hours after surgery and underwent further adjustment, if needed, to achieve the target angle. A further review took place at 2 weeks and 2 months. Children remained under follow-up till 8 years of age. Forty percent needed postoperative adjustment. The mean postoperative angle at final measurement was -2Delta (range +25 to -45). Eighty percent achieved an angle within 10Delta of orthotropia. No gross restrictions of ductions were present postoperatively.

Consecutive Exotropia: Risk Factor Analysis and Management Outcomes

“…Folk et al (4) reported that cases with limitation in eye movements have higher consecutive XT rate, and consecutive XT was observed at almost equal rates between the cases that underwent only BMR surgery and recession-resection surgery. Vishwanath and Ansons (19) reported adduction limitation in the range of 55%-85% in cases that developed consecutive XT. While adduction limitation was present in 9 (30%) cases in group 1, it was only present in 2 (2.9%) cases in group 2 after BMR surgery in the present study.…”

“…Consecutive XT treatment includes LR recession, MR advancement or MR advancement combined with MR resection, combination of LR recession and MR resection, and MR advancement combined with unilateral LR recession (2, 10, 13, 21, 22). Conventional surgical nomograms may not hold good in consecutive XT cases because of altered anatomy and muscle dynamics (19). The most frequently used method in the present study was unilateral MR advancement primarily in cases with adduction limitation.…”

Risk of consecutive esotropia after surgery for intermittent exotropia according to passive duction force

“…Previous evaluations of the PDFs in EOMs in XT surgery suggested an improvement in the predictive accuracy of planned strabismus surgical outcomes. Chronic strabismus may result in fibrosis of the muscle–tendon complex and induce a certain degree of restriction and tension in an EOM that may cause resistance when the eyeball is moving in the opposite direction [ 14 , 15 ]. Chougule and Kekunnaya reported that in patients with large-angle XT, loss of elasticity and consequently a tight LRM could produce a restrictive leash effect [ 17 ].…”

Exotropia

“…We routinely perform a 5-7 mm lateral rectus recession, using adjustable sutures when possible, and a medial rectus advancement, deciding on the amount of advancement intraoperatively (Vishwanath and Ansons 2009). Patients with angles greater than 20 Δ require surgery on two or more horizontal muscles.…”