The long-term result of slanted medial rectus resection in exotropia of the convergence insufficiency type

Abstract

Purpose To evaluate the long-term results of slanted medial rectus (MR) resection for intermittent exotropia (X(T)) of the convergence insufficiency type. Methods In all, 10 patients with an X(T) greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. Patients received slanted bilateral MR resection. The upper edge of the MR was resected according to the distance exodeviation and the lower edge of the MR was resected according to near exodeviation. The postoperative follow-up period was between 6 and 62 months with a mean of 38.9 months. The paired t-test was used to compare: mean distance angle of deviation preoperatively and postoperatively; mean near angle of deviation preoperatively and postoperatively; and mean near-distance exodeviation difference preoperatively and postoperatively. Results Bilateral slanted MR resections reduced mean exodeviation at distance from 23.077.2 to 16.375.4 PD (P ¼ 0.03); mean exodeviation at near from 34.377.7 to 24.676.9 PD (P ¼ 0.01); and mean near-distance difference from 11.472.6 to 8.373.5 PD (P ¼ 0.04). At the final follow-up examination, all patients demonstrated an exodeviation of 10 PD or more at distance and near, and the exodeviation difference between distance and near deviation was within 10 PD in five of the 10 patients. Three patients had an esodeviation at distance after surgery, but all resolved within 4 weeks. Conclusions Bilateral slanted MR resections in patients with X(T) of the convergence insufficiency type resulted in undercorrection in all patients.

Comparison of different surgery procedures for convergence insufficiency-type intermittent exotropia in children

“…The success rates of the surgery ranged from 27 to 67% 1–4. Several surgery procedures with different modifications for CI-type IXT have been used in clinical practice and lead to varied clinical outcomes;2 4 5 7 10 11 13 however, none of these surgery procedures was considered as the ideal surgical method for CI-type IXT. In 1995, Kraft et al 14 first described an improved R&R procedure biased to medial rectus strengthening more than lateral rectus weakening for treatment of exotropia with convergence weakness and got successful results.…”

A comparative study of medial rectus slanting recession versus recession with downward transposition for correction of V-pattern esotropia

“…This finding corresponds to a slant of 2 to 3 mm (mean, 2.1 mm) in the study of Biedner and Rothkoff 9 and a slant of 3 to 4 mm in that of Ohba and colleagues. 14 Slanting recessions 15,16 or resections 13,17,18 also may be used to correct an abnormal AC/A ratio, as in cases of convergence excess esotropia (ie, with high AC/A ratio), 15 or convergence insufficiency exotropia (ie, with low AC/A ratio). 13,[16][17][18] In these situations a larger amount of surgery is performed for the lower muscle poles than the upper to correct the larger angle for near.…”

“…14 Slanting recessions 15,16 or resections 13,17,18 also may be used to correct an abnormal AC/A ratio, as in cases of convergence excess esotropia (ie, with high AC/A ratio), 15 or convergence insufficiency exotropia (ie, with low AC/A ratio). 13,[16][17][18] In these situations a larger amount of surgery is performed for the lower muscle poles than the upper to correct the larger angle for near. 13,[15][16][17][18] Comparing the effect of slanting medial rectus muscle recession to that of medial rectus muscle recession with downward transposition, we used the latter in the TRANS group.…”

“…13,[16][17][18] In these situations a larger amount of surgery is performed for the lower muscle poles than the upper to correct the larger angle for near. 13,[15][16][17][18] Comparing the effect of slanting medial rectus muscle recession to that of medial rectus muscle recession with downward transposition, we used the latter in the TRANS group. The displacement was limited to half-tendon width (5 mm) in all patients in the TRANS group.…”

The change of the extraocular muscle insertion after a slanted recession in rabbit eyes

“…However, Choi and Hwang [8] reported that bilateral slanted MR resections in patients with exotropia of the convergence insufficiency type resulted in undercorrection in all patients.…”