FP908 : Superior Rectus Transposition for Treatment of Esotropic Duane Retraction Syndrome

Dr. Kuldeep Srivastava, S06431

Abstract:

Background:

Superior rectus transposition (SRT) with or without medial rectus recession (MRc) has recently been introduced as a new treatment for esotropic Duane syndrome. The purpose of this study was to study the efficacy and safety of SRT with MRc in treatment of Duane syndrome. Methods: Medical records of patients with esotropic Duane syndrome who underwent SRT with MRc between July 2015 and April 2016 were reviewed. Results: There were six patients of esotropic Duane syndrome who underwent 5.5 mm MRc and SRT with suture augmentation. The mean preoperative and postoperative deviation was 21 PD and 5 PD respectively. Abduction improved in 5 patients (-3.5 to –2.6). Adduction limitation was observed in all patients. One patient developed 8 PD hypertropia and diplopia, which resolved spontaneously in a month time. Conclusion: SRT with MRc was effective in improving abduction, esotropia and compensatory head posture but it has risk of inducing hypertropia causing diplopia.

Patients with Duane Retraction syndrome usually have moderate to severe limitation of abduction, esotropia in primary position, associated compensatory head posture and diplopia on attempted abduction. Various surgical approaches including vertical rectus muscle transposition have been proposed for improving eye position and head posture. Full vertical rectus transposition (VRT) procedures are the most effective procedure for treatment of the abduction deficit in esotropic DRS; however this procedure have been reported to produce vertical deviations in 8 to 40 % of patients 1–2. There is also a risk of anterior segment ischemia with this procedure, especially if combined with medial rectus muscle recession.3 Johnston and Crouch introduced a modification of the VRT in which only the superior rectus muscle is transposed.4 Since then several authors have adopted this superior rectus transposition (SRT) technique for patients with Esotropic DRS.5-7 The purpose of this study was to study the efficacy and safety of SRT with MRc in treatment of Duane syndrome.

Patients and Methods

The medical records of patients treated in the Department of Pediatric Ophthalmology & Strabismus at Indira Gandhi Eye Hospital and Research Centre, Lucknow between July 2015 and April 2016 were reviewed. Patients who had undergone SRT with MRc for the treatment of esotropic DRS were included in the study.

Information extracted from case records were preoperative and postoperative head turn, horizontal and vertical deviation in all gaze positions, ductions, BSV and stereopsis. Information regarding postoperative complications, including surgically induced vertical deviation, diplopia and impairment of adduction were also extracted. Ductions were graded on a scale from 0 to -5 scale (0 – indicating full ductions, − 4 unable to move beyond the midline and −5 eye was unable to reach the midline) Head turn measurements (measured at distance fixation) were recorded from patient records.

Surgical Technique

5.5 mm medial rectus recession was done through a limbal incision.  A limbal conjunctival incision was made from 12 to 3 O’ clock and superior rectus muscle was isolated. After clearing the muscle from surrounding attachments, the muscle was secured with a double arm 6-0 polyglactin (Vicryl) suture. The superior rectus muscle was detached from the globe and was reattached adjacent to lateral rectus muscle along the Spiral of Tillaux. A double armed 5-0 polyester augmentation suture was then placed by passing one needle through the lateral one quarter of the superior rectus muscle and the other needle through the superior one quarter of the lateral rectus muscle, positioning this suture 8 mm posterior to the insertion of the two muscles.8, 9 The suture was then tied to pull the two muscles together similar to loop myopexy, 10 with no scleral pass.

Patients were examined on first postoperative day, at one month post op and six monthly thereafter.

Results

Medical record review identified six patients of esotropic DRS treated with SRT over the study period, all of whom had simultaneous medial rectus recession. Patients were between 8 and 17 years of age. Three patients were male and 3 were female. Left eye was involved in all patients. The average postoperative follow-up was 3 months (range 1– 7 months). Compensatory head turn was 20° or more in all patients. The medial rectus muscle recession was 5.5 mm in all patients. Augmentation sutures with out securing to sclera were placed in all patients. Mean esotropia in primary position improved from 21 PD (15 PD – 35 PD) preoperatively to 5 PD (0 – 10 PD) postoperatively. 3 patients were orthophoric in primary position. Head turn improved in all patients.  Abduction improved in 5 patients (-3.5 to –2.6). Adduction limitation (-1) was observed in all patients. One patient developed surgically induced hypertropia (8 PD) and diplopia, which resolved spontaneously in a month time.

Discussion

Over the past few decades, a variety of vertical rectus muscle transposition procedures have been proposed to improve ocular alignment in patients with abduction limitation. In 2004, Rosenbaum reviewed the results of vertical rectus transposition (VRT) with posterior fixation, orbital fixation, and partial vertical rectus transposition in patients with sixth nerve palsy and Duane syndrome.11 His study showed a marked improvement in the range of binocular single vision of patients who had undergone a VRT with posterior fixation. Surgically induced vertical strabismus is a concern with VRT 1  and also VRT carries a theoretical increase in the risk of anterior segment ischemia, especially if recession of the medial rectus muscle is required.3 Johnston and Crouch 6 were the first to propose that it might be possible to gain the benefits of transposition surgery by transposing only the superior rectus muscle (with or without medial rectus muscle recession), thus reducing the amount of surgery required as well as the theoretical risk of anterior segment ischemia.4 Since then several investigators have shows encouraging results with SRT with or without medial rectus recession.5-7.

Many patients with abduction limitation will develop tightness or contracture of the medial rectus muscle over time. This can limit the effectiveness of a transposition procedure.11 Since we transposed only the superior rectus muscle in our procedure, we had routinely recessed the medial rectus muscle to reduce any potential abduction limitation. The addition of an abducting force to the eye has a theoretical advantage of preventing recurrence of esotropia over time. Since only one muscle is transposed, even patients who have had a prior horizontal rectus muscles recess/resect procedure may also be considered for the SRT.

The results of the SRT + MRc in our study are comparable to the results of the SRT. 5, 7 and VRT 9,12 In our experience, SRT + MRc are superior to recession of the ipsilateral medial rectus muscle (the authors 6 cases of SRT + MRc, there is no way they can comment that it is superior to iplsilateral MR recession, hypothetical and thoeritical comment only) for patients with severe abduction limitations, as the amount of medial rectus muscle recession required tends to cause a new adduction limitation and contributes no chronic abducting force to prevent recurrence.

One of the patients with Duane syndrome in our study developed a hypertropia after surgery which resolved spontaneously in a month time. We do not know the exact reason for this hypertropia but it may be due to insufficient dissection of superior rectus muscle.  This study is limited by small sample size and short follow-up. Also there was no control group treated with medial rectus recession alone.

In conclusion, in patients treated with SRT + MRc, there was a markedly reduced esotropia in primary position, improved head position and increased abduction with minimal effect on adduction. Considering these results, we recommend SRT + MRc for patients with profound abduction limitation in which there is no reasonable chance that a horizontal rectus muscle procedure alone will be satisfactory. The procedure is especially helpful in cases where there may be simultaneous contracture of the medial rectus muscle, as it allows a medial rectus muscle recession to be combined with a transposition procedure without increasing the risk of anterior segment ischemia.

References

1.Ruth AL, Velez FG, Rosenbaum AL. Management of vertical deviations after vertical rectus transposition surgery. J AAPOS. 2009; 13:16–9.

2.Laby DMRosenbaum AL. Adjustable vertical rectus muscle transposition surgery.J Pediatr Ophthalmol Strabismus. 1994; 31: 75-8.

3.Murdock TJ, Kushner BJ. Anterior segment ischemia after surgery on 2 vertical rectus muscles augmented with lateral fixation sutures. J AAPOS. 2001; 5:323–4.

4.Johnston SC, Courch ERC Jr, Crouch ER. An innovative approach to transposition surgery is effective in treatment of Duane’s syndrome with esotropia. Invest Ophthalmol Vis Sci. 2006; 47: E Abstract 2475.

5.Mehendale RADagi LRWu CLedoux DJohnston SHunter DG. Superior rectus transposition and medial rectus recession for Duane syndrome and sixth nerve palsy. Arch Ophthalmol.2012; 130:195-201.

6.Yang S, MacKinnon S, Dagi LR, Hunter DG. Superiorrectustransposition vs medial rectus recession for treatment of esotropic Duane syndrome. JAMA Ophthalmol. 2014;132:669-75.

7.Tibrewal S, Sachdeva V, Ali MH, Kekunnaya R. Comparison of augmentedsuperiorrectus transposition with medial rectus recession for surgical management of esotropic Duane retraction syndrome. J AAPOS. 2015; 19:199-205..8. Foster RS. Vertical muscle transposition augmented with lateral fixation. J AAPOS. 1997; 1:20– 30.

8.Yazdian Z, Rajabi MT, Ali Yazdian M, et al. Vertical rectus muscle transposition for correcting abduction deficiency in Duane’s syndrome type 1 and sixth nerve palsy. J Pediatr Ophthalmol Strabismus. 2010; 47:96–100.

9.Wong I, Leo SW, Khoo BK. Loop myopexy for treatment of myopic strabismus fixus. J AAPOS. 2005; 9:589–91.

10.Rosenbaum AL. Costenbader Lecture. The efficacy of rectus muscle transposition surgery in esotropic Duane syndrome and VI nerve palsy. J AAPOS. 2004; 8:409–19.

11.Britt MT, Velez FG, Velez G, Rosenbaum AL. Vertical rectus muscle transposition for bilateral Duane syndrome. J AAPOS. 2005; 9:416–21.

 

FP348 : The Role of Anterior Segment Optical Coherence Tomography in Strabismus Surgery: Prospective Study
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