Superior Rectus Transposition and Medial Rectus Recession for Duane Syndrome and Sixth Nerve Palsy

CLINICAL SCIENCES Superior Rectus Transposition and Medial Rectus Recession for Duane Syndrome and Sixth Nerve Palsy

Reshma A. Mehendale, MD; Linda R. Dagi, MD; Carolyn Wu, MD; Danielle Ledoux, MD; Suzanne Johnston, MD; David G. Hunter, MD, PhD

Objective: To describe our results using augmented tem- from −4.3 to −2.7 (PϽ.001), and improved compensa- poral superior rectus transposition (SRT) with adjust- tory head posture from 28° to 4° (PϽ.001). Stereopsis able medial rectus muscle recession (MRc) for treat- was recovered in 8 patients (P=.03). Three patients re- ment of Duane syndrome and sixth nerve palsy. quired a reoperation: 1 for overcorrection and 2 for un- dercorrection. A new primary position vertical devia- Methods: Retrospective surgical case review of pa- tion was observed in 2 patients with complex sixth tients undergoing SRT. Preoperative and postoperative nerve palsy and none with Duane syndrome. No patient orthoptic measurements were recorded. Minimum fol- described torsional diplopia. low-up was 6 weeks. Main outcome measures included the angle of esotropia in the primary position and the angle Conclusions: Superior rectus transposition allows for of head turn. Secondary outcomes included duction limi- the option of simultaneous MRc in patients with severe tation, stereopsis, and new vertical deviations. abduction imitation who require transposition surgery. Combining SRT and MRc improved esotropia, head po- Results: The review identified 17 patients: 10 with sition, abduction limitation, and stereopsis without in- Duane syndrome and 7 with sixth nerve palsy. Combin- ducing torsional diplopia. ing SRT with MRc improved esotropia from 44 to 10 prism diopters (PϽ.001), reduced abduction limitation Arch Ophthalmol. 2012;130(2):195-201

ATIENTS WITH DUANE SYN- (SRTϩMRc).7 The purpose of this study drome and sixth nerve palsy was to report and evaluate the results of have moderate to severe limi- SRTϩMRc to correct the esotropia and tation of abduction, often head turn in patients with Duane syn- leading to primary position drome or sixth nerve palsy. esotropiaP that is associated with a compensatory head posture, reduced stereop- METHODS sis, and diplopia. Various approaches to improving eye position have been proposed, including partial and full vertical This retrospective study was approved by the rectus muscle transposition (VRT) to in- institutional review board of Children’s Hos- crease the abduction of the eye. Full VRT pital Boston. We reviewed the medical records of patients treated in the Department of procedures are among the most effective Ophthalmology at Children’s Hospital Boston for treatment of the abduction deficit; how- from January 1, 2006, through October 31, ever, new vertical deviations have been de- 2010. Patients treated with SRT, with or with- scribed in 6% to 30% of patients.1-3 There out augmentation suture,8 were included. Ex- is also the concern of anterior segment is- clusion criteria consisted of being younger than chemia with this procedure, especially 1 year, having had prior transposition sur- when a medial rectus muscle recession gery, or having follow-up of less than 4 weeks. (MRc) is also required.4,5 Information obtained included preoperative and Johnston et al6 introduced a modifica- postoperative head turn, esotropia and hyper- tion of the VRT in which only the supe- tropia in all gaze positions, ductions, and stereopsis. Postoperative complications were also Author Affiliations: rior rectus muscle is transposed. Since monitored, including the development of a new Department of Ophthalmology, then, we have adopted this superior rec- vertical misalignment or torsion, impairment Children’s Hospital Boston and tus transposition (SRT) technique for ap- of adduction, and the need for reoperation or Harvard Medical School, propriate patients, usually combining an a revision procedure to improve ocular align- Boston, Massachusetts. augmented SRT with an adjustable MRc ment (excluding postoperative adjustment of

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Augmentation suture MRc with adjustable suture SRT along spiral of Tillaux 8-12 mm posterior to insertion

Figure 1. Diagram representation of the superior rectus transposition (SRT) plus medial rectus recession (MRc) procedure. A, The MRc procedure with adjustable sutures. B, The SRT technique with augmentation suture. The amount of muscle included in the augmentation suture appears in the rendering to be less than one-quarter of the muscle width after tying the knot.

adjustable sutures). Alignment was recorded from the orthop- with no scleral pass (specific exceptions are noted in para- tic evaluation results. Ductions were graded on a scale from 0 graph 3 of the “Results” section) (Figure 1B). (indicating full ductions) through −4 (indicating an eye that Patients underwent assessment in the recovery room 1 to 3 was able to move to the midline) and −5 (indicating an eye that hours after the procedure to check alignment and perform su- approached but was unable to reach the midline) to a maxi- ture adjustment if required. The short tag noose approach al- mum of −8 (indicating a rare case where the eye was fixed in lowed for a second suture adjustment to be performed (if re- an extreme adducted position). Head turn measurements (required) within 10 days of the procedure. The postoperative corded at distance fixation) were taken from patient records follow-up visit was scheduled for 6 to 12 weeks after surgery. or, for 2 patients, measured by estimation using preoperative and postoperative photographs. STATISTICAL ANALYSIS SURGICAL TECHNIQUE The paired t test was used to analyze the preoperative and post- After a “short tag noose” adjustable MRc (described by Niha- operative results on head turn, esotropia in primary position, lani et al7 and Hunter et al9) was performed (Figure 1A), a and limitation of abduction. Stereopsis data were compared using superotemporal incision was made and the superior rectus the McNemar test. A P value of less than .05 was considered muscle was isolated. The muscle was then cleared of surround- statistically significant. ing attachments, with extra care taken to separate the superior rectus muscle from the levator muscle (best achieved by re- RESULTS moving the lid speculum and using a handheld retractor for exposure) and the superior oblique tendon. The muscle was then secured with a double-armed, 6-0 polyglactin 910 suture The medical record review identified 17 patients treated and detached from the globe. The posterior surface of the muscle with SRT during the study period, all of whom had si- was inspected for remaining attachments to the superior oblique multaneous MRc. Patient characteristics and severity grad- tendon or the frenulum. The temporal pole of the muscle was ing of all patients are summarized in Table 1. The av- reattached adjacent to the superior pole of the lateral rectus erage postoperative follow-up was 8 (range, 2-32) months, muscle, and the nasal pole was reattached adjacent to the tem- with 9 patients followed up for 6 months or longer. poral pole of the superior rectus muscle insertion following the Patients with Duane syndrome were younger than spiral of Tillaux (Figure 1B). In most cases, a double-armed 6-0 those with sixth nerve palsy. The average abduction defi- polyester augmentation suture was then placed by passing one needle through the lateral one-quarter of the superior rectus cit was greater in the sixth nerve palsy group. All pa- muscle and the other needle through the superior one-quarter tients had a compensatory head turn of more than 20°. of the lateral rectus muscle, positioning this suture 8 to 12 mm The mean MRc was 5 mm. Postoperative adjustment posterior to the insertion of the 2 muscles.2,10,11 The suture was was performed in 7 of 17 patients. The final amount of then tied to pull the 2 muscles together as a loop myopexy,12 recession ranged from 0 to 8 mm after adjustment, but

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©2012 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 10/01/2021 only 1 patient had a recession of more than 6 mm. In 6 cases, there were minor variations from the surgical tech- Table 1. Patient Demographics and Distribution nique noted in the “Methods” section. One patient, the first in the series, did not have an augmentation suture Patient Groups placed. In 3 patients, the polyester augmentation suture Duane Sixth Nerve was secured to the sclera; 1 of these patients also under- Syndrome Palsy went a simultaneous 9-mm recession of the lateral rec- (n = 10) (n=7) tus muscle to correct globe retraction. Three patients, all Age range, mo 1 to 33 6 to 60 with a primary position esotropia of at least 50 prism di- Sex, No. of patients opters (⌬), had a simultaneous or a subsequent reces- Male 6 1 sion of the contralateral medial rectus muscle. Female 4 6 Follow-up, mo 2 to 32 2 to 16 Mean (SD) esotropia in the primary position im- ⌬ ⌬ ⌬ ⌬ Abduction deficit, U −3 to −5 −4 to −5 proved from 44 (16 ) preoperatively to 10 (9 ) post- Head turn Ͼ20°, No. (%)a 10/10 (100) 7/7 (100) operatively (Figure 2A; PϽ.001). Five patients be- Stereopsis, No. (%)b came orthophoric at distance in the primary position Preoperative 4/9 (44) 1/6 (17) without spectacle correction. There was also a mean 21° Postoperative 8/9 (89) 5/6 (83) improvement in head turn (from 28° to 4°, Figure 2B; Ͻ a Patients used a head turn for fusion or for fixation. P .001) and a 1.6-unit improvement in abduction (from b Data were not included for 1 patient with Duane syndrome (not recorded) −4.3 to −2.7, Figure 3A; PϽ.001), with a 0.6-U reduc- and 1 patient with sixth nerve palsy (blind in 1 eye). Improvement was tion in adduction (Figure 3B; P=.009). The improve- statistically significant (P = .03). ment in head turn and abduction is documented in a rep- resentative pediatric patient (Figure 4). Stereopsis in duction limitation after surgery; this patient was treated the primary position was measurable in 5 of 17 patients with reversal of the transposition, recession of the lat- (29%) before surgery and improved to 13 of 17 patients eral rectus muscle, and advancement of the medial rec- (76%) after surgery (Table 1; P=.03). tus muscle so that the final net procedure was simply a New-onset vertical deviations in the primary posi- 2-mm MRc and lateral rectus recession. tion (mean [SD], 10⌬ [2.8⌬]) were observed in 2 patients (12%). Both patients had chronic sixth nerve palsy; one of these patients was a 16-year-old boy described in COMMENT the paragraph about second procedures, whereas the other patient had multiple orbital fractures in addition to a sixth During the past century, a variety of partial and full trans- nerve palsy. No patient with Duane syndrome had an in- position procedures of the vertical rectus muscles have been duced vertical deviation. There was no new-onset, symp- proposed in an effort to improve eye alignment in pa- tomatic hypotropia in gaze toward the affected side. In tients with abduction limitation.2,8,13-18 In 2004, Rosen- several cases, a hypotropia was already evident in the af- baum14 reviewed the results of VRT with posterior fixa- fected eye before surgery owing to aberrant innervation tion, orbital fixation, and partial VRT in patients with sixth (eg, Figure 4) or multiple cranial nerve palsies. nerve palsy and Duane syndrome. His study showed a Torsion was assessed postoperatively in 6 patients using marked improvement in the range of binocular single vi- the double Maddox rod test (3 patients) or anatomic torsion of patients who had undergone a VRT with posterior sion (3 patients). Of these, 2 patients did not have tor- fixation. Phamonvaechavan et al19 have described a vessel- sion and 3 had incyclotorsion (mean, 4°; values, 2°, 2°, sparing, “crossed adjustable” VRT that allows for adjust- and 5°). None of these patients were symptomatic. In an- ment of the superior and inferior rectus muscles; this tech- other case, the augmentation suture (placed through the nique does not allow for an augmentation suture. sclera) was removed in the postanesthesia care unit to New vertical strabismus is a concern with VRT; in one reverse incyclotorsion and diplopia that were noted in report,1 6% to 30% of patients treated with VRT had a the immediate postoperative period; however, at the fi- clinically significant new vertical strabismus. Vertical rec- nal postoperative visit, that patient had 2° to 3° excyclo- tus transposition also carries a theoretical increase in the torsion. risk of anterior segment ischemia, especially if MRc is re- A second procedure was required in 3 cases. Two pa- quired.4,5 Johnston et al6 were the first to propose that it tients had undercorrections; one was a 4-year-old boy with might be possible to gain the benefits of transposition sur- a residual esotropia of 20⌬ who responded to full hy- gery by transposing only the superior rectus muscle (with peropic correction and a 7.5-mm recession of the con- or without MRc), thus reducing the amount of surgery tralateral medial rectus muscle. The second was a 16- required and the theoretical risk of anterior segment is- year-old boy with a sixth nerve palsy secondary to pilocytic chemia. We adopted this technique, modifying it with astrocytoma (after irradiation) who developed a recur- the addition of a short tag noose adjustable suture7 on rence (with a 14⌬ hypotropia) during the first 2 months the medial rectus muscle to allow for optional suture ad- after surgery. He was subsequently treated with an aug- justment up to 14 days after surgery, along with routine mented inferior rectus transposition, which partially re- use of an augmentation suture. duced the head turn and improved the esotropia from Many patients with abduction limitation will de- 25⌬ to 10⌬ but with a persistent hypotropia. The over- velop tightness or contracture of the medial rectus muscle correction occurred in a 1-year-old girl with Duane syn- over time. This condition can limit the effectiveness of a drome who developed a consecutive exotropia and ad- transposition procedure.14 Because we transposed only

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Δ 60 60

40 40 20

0 20 Head Turn, Degrees Head Turn,

Angle of Primary Gaze, – 20

– 40 0

– 60 Preoperative 2-mo Final Preoperative 2-mo Final Postoperative Postoperative Postoperative Postoperative

Figure 2. Surgical results. A, Change in alignment in primary gaze position (n=17). Positive values represent esotropia. B, Change in head turn (n=16). Head turn was not assessed in 1 patient who did not demonstrate fusion. Final postoperative visit represents a mean follow-up of 8 (range, 2-32) months. The bottom and top of each box represent the 25th and 75th percentiles (the lower and upper quartiles, respectively); the band near the middle of the box is the 50th percentile (the median). The ends of the whiskers represent the minimum and maximum of all the data. Any data not included within the whisker are plotted as outliers (dots). For preoperative vs final findings, PϽ.001 (paired t test). ⌬ indicates prism diopters.

A B 0 0

– 1 – 1

– 2 – 2 – 3 – 3 – 4

Limitation of Abduction, U Limitation of Adduction, U – 4 – 5

– 6 – 5 Preoperative 2-mo Final Preoperative 2-mo Final Postoperative Postoperative Postoperative Postoperative

Figure 3. Ductions before and after surgery (n=17). A, Abduction limitation (PϽ.001 for preoperative vs final values [paired t test]). B, Adduction limitation (P=.01 for preoperative vs final values [paired t test]). Final postoperative visit represents a mean follow-up of 8 (range, 2-32) months. To prevent the measurements of 1 patient with overcorrection from confounding postoperative averages, we reanalyzed the values after excluding that patient and found no substantive change in the calculated means or P values. The bottom and top of each box represent the 25th and 75th percentiles (the lower and upper quartiles, respectively); the band near the middle of the box is the 50th percentile (the median). The ends of the whiskers represent the minimum and maximum of all the data. Any data not included within the whisker are plotted as outliers (dots).

the superior rectus muscle in our procedure, we were com- astrocytoma), the subsequent transposition of the infe- fortable performing routine MRc to reduce any poten- rior rectus muscle improved the ocular alignment. In our tial abduction limitation. By making this recession ad- experience, SRTϩMRc and VRT are superior to ipsilat- justable, we were able to fine-tune the horizontal eral MRc alone for patients with severe abduction limi- alignment in the postoperative period, an added benefit tations because the amount of MRc required alone tends considering that a transposition procedure might have a to cause a new adduction limitation and MRc contrib- less predictable result on horizontal alignment than a re- utes no chronic abducting force to prevent recurrence. cession or resection. The addition of an abducting force One patient experienced overcorrection, but we do not to the eye has a theoretical advantage of preventing re- believe it was a result of the transposition because, after currence of esotropia over time, but the duration of fol- fully reversing the transposition, the overcorrection per- low-up in the present study is not sufficient to address sisted until the previously recessed medial rectus muscle this question. Because only 1 muscle is transposed, even was advanced (and the lateral rectus muscle was re- patients who have had a prior recession or resection may cessed). None of the patients with Duane syndrome de- be considered candidates for the SRT (or the SRTϩMRc) veloped a hypotropia after surgery, but 2 patients with procedure. sixth nerve palsy did; we believe these two were anoma- The results of SRTϩMRc in our hands appear to be lous cases because one had orbital fractures requiring sur- comparable to the results of VRT (Table 2 and gery and the other had the augmentation suture at- Table 3).10,20-23 However, in one patient with undercor- tached to the sclera. Torsional diplopia was not a problem, rection (with a sixth nerve palsy secondary to pilocytic except in one unusual case in which the patient (treated

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Figure 4. Head position and motility in a boy aged 51⁄2 years. A and C, Preoperative views. B and D, Two-month postoperative views. The patient underwent augmented superior rectus transposition and a 4.5-mm left medial rectus muscle recession.

Table 2. Comparison of Results of VRT and SRT for Treatment of Esotropia in Duane Syndromea

VRT, Source ,SRT ؉ MRc Rosenbaum14 Yazdian et al10 Present Study (n = 64) (n = 38) (n = 10)

Preoperative Postoperative Preoperative Postoperative Preoperative Postoperative Head turn, degrees 20 5 38 12 24 3 Esotropia, ⌬ 19 6 32 9 37 10 Abduction, U (change, %) −3.8 −2.7 (29) −4 −2 −4 −2 (50) Postoperative follow-up, mo 11 18 8 Induced vertical deviation, 5/64 3/38 0/10 No. of patients

Abbreviations: ⌬, prism diopters; MRc, medial rectus muscle recession; SRT, superior rectus muscle transposition; VRT, vertical rectus muscle transposition. a Unless otherwise indicated, data are expressed as mean values.

with scleral fixation of the augmentation suture) de- yet that patient ended up with excyclotorsion after sur- scribed such distressing torsional diplopia in the recov- gery. Although it is not possible to make general recom- ery room that the suture was removed before discharge, mendations about the augmentation suture based on the

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©2012 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 10/01/2021 Table 3. Comparison of Results of VRT and SRT for Treatment of Esotropia in Sixth Nerve Palsya

VRT, Yazdian et al10 SRT ؉ MRc, Present Study (n = 24) (n=7)

Preoperative Postoperative Preoperative Postoperative Head turn, degrees 24 7 36 5 Esotropia, ⌬ 44.7 12.5 53.5 16.8 Abduction, U −4.2 −2.3 −4.8 −3.0 Follow-up, mo 18 10 Induced vertical deviation, 0/24 2/7 No. of patients Reoperation, No. of patients 6/24 1/7

latter 2 cases, we advise surgeons adopting the SRT pro- duction limitation in which there is no reasonable chance cedure to use a simple loop myopexy of superior rectus that a horizontal rectus muscle procedure alone will be muscle to lateral rectus muscle for augmentation until satisfactory. The procedure is especially helpful in cases more experience is gained and published. in which there may be simultaneous contracture of the This study is limited by its retrospective nature and medial rectus muscle, because it allows an MRc to be com- the follow-up of less than 6 months in 8 patients (47%). bined with a transposition procedure without greatly in- No control group was treated with MRc alone. Some pa- creasing the risk of anterior segment ischemia. tients were too young to assess stereopsis adequately at the initial examination; therefore, some of the observed Submitted for Publication: December 8, 2010; final improvement in stereopsis may have been the result of revision received June 27, 2011; accepted June 29, patient maturation. Many patients were also too young 2011. to permit objective assessment of torsion. Field of bin- Correspondence: David G. Hunter, MD, PhD, Depart- ocular vision was not tested in this retrospective study; ment of Ophthalmology, Children’s Hospital Boston, 300 however, the 1.6-U improvement in abduction com- Longwood Ave, Fegan 4, Boston, MA 02115 (david.hunter bined with a 0.6-U limitation of adduction is consistent @childrens.harvard.edu). with an increase in the range of motion of the eye. Financial Disclosure: None reported. The study addresses only temporal SRT; it does not 24 Funding/Support: This study was supported in part by address the question of nasal SRT. We performed na- the Children’s Hospital Ophthalmology Foundation. The sal SRT in one patient but had to reverse the procedure statistical work was conducted with partial support from 3 days later owing to intolerable torsional diplopia. This Harvard Catalyst, The Harvard Clinical and Transla- patient was not included in the present study. tional Science Center, by award UL1 RR 025758 from the We can only speculate how a vertical deviation and National Institutes of Health and financial contribu- torsional diplopia did not result from an unbalanced trans- tions from Harvard University and its affiliated aca- position of the superior rectus muscle. We believe that demic health care centers. because the transposition also involves a slight advance- Disclaimer: The content is solely the responsibility of the ment of the superior rectus muscle (to follow the spiral authors and does not necessarily represent the official views of Tillaux), the procedure increases the effective strength of Harvard Catalyst, Harvard University and its affiliated of the superior rectus muscle to counterbalance the weak- academic health care centers, the National Center for Re- ening of the vertical effect that results from the transpo- search Resources, or the National Institutes of Health. sition. However, such an alteration of the superior rec- Previous Presentation: This study was presented at the tus muscle insertion, extending the temporal edge to the American Association for Pediatric Ophthalmology and Stra- lateral rectus tendon insertion and then following the bismus Meeting; April 17, 2011; San Diego, California. muscle to the point of the augmentation suture, should Additional Contributions: Sarah Mackinnon, OC(C), increase torsion that much further. Enhanced modeling MSc, lead orthoptist, Department of Ophthalmology, of the forces operating within the orbit may be required assisted with orthoptic measurements and interpreta- to begin to explain this apparent inconsistency. The clini- tion of head turn photographs. Ethan Bickford, BFA, cally insignificant hypotropia noted in abduction in sev- formatted the clinical images. Peter Forbes, MA, senior eral cases after surgery appeared to be a consequence of biostatistician, Children’s Hospital Boston, helped with aberrant innervation because it was present before sur- statistical analysis. gery in all patients. In conclusion, in patients undergoing SRTϩMRc, there was a markedly reduced esotropia in the primary posi- REFERENCES tion, increased abduction, and improved head position 1. Ruth AL, Velez FG, Rosenbaum AL. Management of vertical deviations after ver- with minimal effect on adduction and few cases of vertical rectus transposition surgery. J AAPOS. 2009;13(1):16-19. tical or torsional diplopia. Considering these results, we 2. Velez FG, Foster RS, Rosenbaum AL. Vertical rectus muscle augmented trans- recommend SRTϩMRc for patients with profound ab- position in Duane syndrome. J AAPOS. 2001;5(2):105-113.

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