- Email: [email protected]
Three-muscle surgery for very large-angle constant exotropia
Three-muscle surgery for very large-angle constant exotropia Jun Hong Li, MD, PhD, and Li Jun Zhang, MD PURPOSE METHODS
RESULTS
CONCLUSIONS
To report the outcomes of surgery on three horizontal muscles for very large-angle constant exotropia. In this prospective case series, consecutive adult patients with primary constant exotropia with angles $120D underwent strabismus surgery on three horizontal muscles. Surgery consisted of lateral rectus recession of 10–15 mm on the fixing eye in addition to lateral rectus recession of 9–13 mm and medial rectus resection of 6.5–9 mm on the nonfixing eye. The mean follow-up period was .6 months. Success was defined as horizontal esoor exodeviations of #10D. A total of 23 patients were included. The mean age at surgery was 30.4 9.3 years (range, 16-52). The mean preoperative near exodeviation was 128D 9.8D; the mean preoperative distance exodeviation, 130D 10.4D. The mean follow-up period was 8.1 1.4 months. At the last follow-up, 19 of the 23 cases (83%) were successfully aligned. At final follow-up examination, the mean postoperative exodeviation was 5D 4.2D (near) and 5D 4.3D (distance); no patient had diplopia on lateral gazes. In this patient cohort, surgery on three-muscle surgery for very large-angle exotropia successfully restored alignment in primary gaze in over 80% of cases without inducing symptomatic abduction deficits. ( J AAPOS 2013;17:578-581)
T
he best surgical approach for correcting very large-angle exotropia is still controversial. Lau and colleauges1 reported results of single-staged strabismus surgery on three horizontal muscles to restore primary position alignment for patients with large-angle exotropia (60D-85D) with no limitation of eye movement or diplopia. Recently, Chang and colleagues2 reported no significant symptomatic eye movement deficits after medial rectus resection of 9–11 mm and a lateral rectus muscle recession of 10–14 mm in 4 adults with sensory exotropia who had a mean deviation of 82D (range, 75D-90D). The purpose of the present study was to report the results of surgery on only three horizontal muscles to treat very large exotropias.
Patients and Methods This study was approved by the Shanxi Eye Hospital Ethics Committee and followed the tenets of the Declaration of Helsinki. Consecutive patients with primary extra-large angle exotropia ($120D at near and distance) undergoing strabismus surgery at
Author affiliations: Shanxi Eye Hospital, Shanxi Medical University, Taiyuan, China Submitted July 24, 2012. Revision accepted August 26, 2013. Published online November 7, 2013. Correspondence: Jun Hong Li, MD, PhD, Shanxi Eye Hospital, Shanxi Medical University, No.100 Fudong street, Taiyuan 030002, China (email: [email protected]). Copyright Ó 2013 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2013.07.015
578
Shanxi Eye Hospital from May 2011 to April 2012 were included. Patients with paralytic strabismus, a history of prior strabismus surgery, ocular comorbidities excepting refractive error and amblyopia, restricted eye movements, or strabismus with a secondary cause were excluded. The angle of deviation was measured by the alternate cover and prism test using single loose prisms 1D-80D. The 80D prism was routinely placed in front of one eye, while another of increasing strength was placed before the other eye until there was neutralization of eye movement. Prisms were stacked in front of one eye for exotropic deviations .140D. For example, we placed an 80D base-in prism in front of one eye and a 60D basein prism front of the other for 140D and placed an 80D base-in prism in front of one eye and a combined 60D base-in prism plus a 10D base-in prism in front of the other eye for 150D. This method of stacking prisms was not accurate and provided only a rough estimate of the preoperative deviation for deviations more than 140D. All patients underwent a complete ophthalmological examination before and after surgery. Forced duction test was performed in all patients before surgery. The preoperative distance deviation, surgical details, postoperative angle measurement at the last follow-up, postoperative abduction deficits of both eyes at the last follow-up, and length of follow-up were recorded (Table 1). Patients were reassessed at postoperative day 1, week 3, month 2, and every 2-3 months thereafter. All cases were followed for at least 6 months after surgery. Postoperative deviations with near and distance targets were measured by alternate prism and cover testing. Ductions and versions were measured at each follow-up examination.
Journal of AAPOS
Volume 17 Number 6 / December 2013
Li and Zhang
579
Table 1. Average surgical resultsa Surgery in nonfixing eye Pre-op dev 150 140 130 120
Post-op dev, PD
Number of cases
Surgery in fixing eye, mmb
LR recession, mm
MR resection, mm
2 6 5 10
15 13.8 12.8 10.3
12 11.7 10.8 9.6
8 8.3 7.6 7.4
Near 9 7.3 3.8 2.2
Distance
Abduction deficit Fixing eye, mm
11 7.3 3 3.3
1 1.2 0.6 0.7
Nonfixing eye, mm
Follow-up, months
2 1.8 1.6 1
7 8.8 8 7.9
Dev, deviation; LR, lateral rectus muscle; MR, medial rectus muscle; PD, prism diopters; Post-op, postoperative; Pre-op, preoperative. Negative values indicate exotropia for strabismus deviations. b LR recession. a
All operations were performed under topical anesthesia by one surgeon (JHL). A fornix approach was used for all muscles. The recession of the lateral rectus was performed with direct scleral fixation suture 10 mm from the insertion of the muscle combined with a hang-back suture using 6-0 polyglactin 910. All muscle recession and resection measurements were measured from the muscle insertion. All patients underwent surgery on three muscles, including lateral rectus recessions on the fixing eye and lateral rectus recession combined with medial rectus resection on the nonfixing eye. Some patients had adjustable sutures on all three muscles; sutures were adjusted at the time of surgery. In brief, bilateral lateral rectus recessions were performed and two slip knots were placed on the bilateral lateral rectus muscle. The medial rectus resection of 9 mm was then performed. The medial rectus muscle was recessed 1 mm from the original insertion in order to leave room for subsequent advancement. A slip knot was placed on the medial rectus muscle. The suture was tightened or loosened to change the eye position. After adjusting the medial rectus muscle resection, both lateral rectus muscle recessions were adjusted in order to achieve 10D of esotropia. After using adjustable sutures on all three muscles in the first 7 patients, a surgical dose for lateral rectus muscle recessions based on the preoperative deviation was established. The preoperative maximum abduction magnitude was measured by the corneal diameter minus the distance from the nasal limbus to the lateral canthus when the eye was maximally abducted. The lateral rectus muscle of the fixing eye was recessed a predetermined amount based on the preoperative deviation. Then the lateral rectus muscle of the nonfixing eye was recessed a predetermined amount based on the preoperative deviation and preoperative maximum abduction magnitude. The lateral rectus muscle of the fixing eye was recessed $1 mm if the preoperative maximum abduction magnitude of this eye was $ 13 mm for patients with 120D-140D exotropia (Table 2). Finally, the medial rectus muscle was resected on an adjustable suture for the remainder of the patients. The medial rectus muscle was then adjusted in order to achieve 10D of esotropia. Unilaterial or bilaterial inferior oblique recession or an upward transposition of the lateral rectus muscle of one-half tendon width and a downward transposition of the medial rectus of onehalf tendon width was performed for patients with V pattern. Successful motor alignment was defined as within 10D of exoor esodeviation.3
Journal of AAPOS
Table 2. Surgical doses for the lateral rectus muscle recessions based on the preoperative measurements Pre-op dev (distance), PDb 150 140 130 120
LR recession in fixing eye, mm
LR recession in nonfixing eye, mma
15 15 12 10
12 12-13c 11-12c 9-10c
Dev, deviation; LR, lateral rectus muscle; PD, prism diopters; Pre-op, preoperative. a In addition to medial rectus resection of 6.5–9 mm. b Negative values indicate exotropia for strabismus deviations. The dosing table was used for 16 patients in this study except 7 patients with all three muscles on an adjustable suture. c The lateral rectus muscle was recessed 1 mm more in the nonfixing eye if the preoperative maximum abduction magnitude of this eye was $3 mm for patients with 120D-140D of exotropia. Two patients had 150D of exotropia and received the same dose of lateral rectus recession on both nonfixing eyes. All measurements are reported as mean and standard deviation. SPSS 11.5 for Windows (SPSS Inc, Chicago, IL) was used for statistical analyses.
Results A total of 23 patients (12 males) were included. All patients had constant concomitant exotropia. The mean age at operation was 30.4 9.3 years old (range, 16-52 years old). All patients had best-corrected visual acuity .6/9 (Snellen) in each eye. The overall mean preoperative deviation was 128D 9.8D (range, 120D-150D) at near and 130D 10.4D (range, 120D-150D). Eight patients (35%) had a V pattern, with .15D greater exotropia inupthan downgaze. Forced duction testing revealed no restriction in any patient. Seven patients had all three muscles on an adjustable suture. The lateral rectus muscles were recessed a predetermined amount based on the preoperative deviation and maximum abduction magnitude (Table 2) followed, in 16 patients, by adjusting the medial rectus muscle resection on an adjustable suture. The mean follow-up period was 8.1 1.4 months (range, 6-10 months). The goal of 10D of esotropia was
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Volume 17 Number 6 / December 2013
FIG 1. A, Clinical photographs of 43-year-old woman with a constant concomitant exotropia of 150D before surgery. Right lateral rectus recession of 15 mm, left lateral rectus recession of 12 mm and left medial rectus resection of 8 mm were performed. B, Alignment in primary position alignment was successfully restored; the deficit of lateral rectus muscle was 2 mm in right eye and 3 mm in left eye at day 1 after surgery. Her upper eyelid had mild edema on left eye. C, The lateral rectus was almost full on right eye and the deficit of lateral rectus was 1 mm in left eye in 3 weeks after surgery. D, The lateral rectus muscle was almost full bilaterally in 7 months after surgery.
achieved in 19 patients (82.6%); there were no cases of overcorrection or consecutive esodeviations. All patients with residual deviations were exotropic. The overall mean near angle of postoperative exodeviation at the last follow-up was 5D 4.2D (range, 0D-13D), and was also 5D 4.3D (range, 0D-17D) at distance. In 4 patients (17.4%) there was an esotropia of 3D-8D after adjustment. The mean lateral rectus recession performed was 12.2 2.0 mm (range, 10-15 mm) on fixing eyes. The mean lateral rectus recession was 10.6 21.3 mm (range, 9–13 mm) and the mean medial rectus resection performed was 7.7 0.6 mm (range, 6.5–9 mm) on nonfixing eyes. The mean surgical dosage is listed in Table 1. The limitation of abduction resulting from bilateral lateral rectus supramaximal recession procedure was significant immediately after surgery and only on the day of surgery. Limitation of abduction significantly improved on postoperative day 1 (Figure 1) and recovered gradually over time. The abduction of the lateral rectus muscle with a supramaximal recession was almost full 3 weeks postoperatively in most cases (Figures 1-2). The mean deficit of lateral rectus abduction using the method described above was 0.8 0.7 mm (range, 0–2 mm) in the fixing eye and 1.3 0.7 mm (range, 0–3 mm) in the nonfixing eye at the last follow-up. There was no symptomatic postoperative eye movement deficit in any patient at final follow-up.
None of the patients demonstrated binocular function either before or after surgery, and none experienced diplopia in primary gaze postoperatively. Two patients had diplopia on extreme lateral gazes. Their diplopia had resolved by 3 weeks after surgery. Of the 23 cases, 22 (95.7%) were satisfied with their cosmetic appearances at final follow-up. One patient required a second medial rectus resection of 5 mm on the fixing eye for 17D of residual exotropia. The second operation was successful.
Discussion The main goal of surgery in patients with large-angle exotropia without binocular function should be improved alignment in primary gaze, with a secondary goal of a normal range of duction in each eye. This study reports the surgical results of our current surgical technique of operating on only three horizontal muscles to treat very large-angle exotropia. The technique successfully treated 19 or 23 patients in this Chinese cohort without inducing symptomatic abduction deficits. Surgeries involving two, three, or four muscles have been reported for treatment of very large-angle exotropia has been reported.1-3 Berland and colleagues4 reported a success rate of 80% with 8–9 mm bilateral lateral rectus recession, but with abduction limitations in 30% of the
Journal of AAPOS
Volume 17 Number 6 / December 2013
Li and Zhang
581
FIG 2. A, Clinical photographs of a 36-year-old woman with 130D constant concomitant exotropia before surgery. Left lateral rectus recession of 12 mm, right lateral rectus recession of 11 mm and right medial rectus resection of 7 mm were performed. B, Both eyes were straight in primary position and the deficit of lateral rectus muscle was 2 mm in the right eye and 1 mm in the left eye 18 days after surgery.
24 patients studied. Some studies of large-angle exotropia have reported success rates ranging from 70% to 80% in bilateral lateral rectus recessions, without significant abduction limitations.1-2,5-9 Lau and colleagues1 reported a 70% success rate with 24 patients with a mean angle of deviation of 71.5D who underwent single-stage threemuscle surgery that consisted of bilateral lateral rectus recession of 9 mm for 50D and unilateral medial rectus resection of 1 mm for every 5D remaining angle. No significant postoperative abduction deficit was noted in any patient. Chang and colleagues2 found that there was no significant symptomatic postoperative eye movement deficit after a medial rectus muscle resection of 9–11 mm and a lateral rectus muscle recession 10–14 mm in 4 adult sensory exotropia patients with a mean deviation of 82.3D. Exotropia deviations .120D in adults are common in China but rare in the West. There has been little literature addressing the results of constant exotropia of $ 120D. Like Chang and colleagues,2 we found no symptomatic postoperative eye movement deficit in any of our patients at final follow-up. The limitation of abduction resulting from the lateral rectus supramaximal recession procedure was notable immediately after surgery but improved quickly. In all subjects, the postoperative alignment drifted toward exotropia and the abduction improved as the lateral rectus muscle healed. It is possible that the lateral rectus muscle “crept” forward, accounting for the improvement in abduction and the return of exotropia. In our data, the nonfixing eye had a greater abduction deficiency than the fixing eye. This might be because the nonfixing eye simultaneously underwent large medial rectus resection, perhaps temporarily increasing the resistance of the medial rectus muscle to abduction.
Journal of AAPOS
One patient in our study underwent a secondary surgery because she was not satisfied with her undercorrection. The medial rectus resection in the fixing eye was performed for this residual exotropia. We think that keeping an intact or untouched muscle is good for the complication of undercorrection after three-muscle surgeries. This study limited by the fact that our postoperative measurements of the deviations in the primary position and the abduction deficit were unmasked. Although our technique did not create a large abduction deficit in either eye, measurements of the eye alignment in eccentric gaze would be helpful to better quantify the effects in eccentric gaze. References 1. Lau FH, Fan DS, Yip WW, Yu CB, Lam DS. Surgical outcome of single-staged three horizontal muscles squint surgery for extra-large angle exotropia. Eye 2010;24:1171-6. 2. Chang JH, Kim HD, Lee JB, Han SH. Supermaximal recession and resection in large-Angle sensory exotropia. Korean J Ophthalmol 2011;25:139-41. 3. Livir-Rallatos G, Gunton KB, Calhoun JH. Surgical results in largeangle exotropia. J AAPOS 2002;6:77-80. 4. Berland JE, Wilson ME, Saunders RB. Results of large (8–9 mm) bilateral lateral rectus muscle recessions for exotropia. Binocul Vis Strabismus Q 1998;13:97-104. 5. Celebi S, Kukner AS. Large bilateral lateral rectus recession in large angle divergence excess exotropia. Eur J Ophthalmol 2001;11:6-8. 6. Currie ZI, Shipman T, Burke JP. Surgical correction of large-angle exotropia in adults. Eye 2003;17:334-9. 7. Rayner JW, Jampolsky A. Management of adult patients with large angle exotropia and amblyopia. Ann Ophthamol 1973;5:95-9. 8. Schwartz RL, Calhoun JH. Surgery of large angle exotropia. J Pediatr Ophthalmol Strabismus 1980;17:359-63. 9. Mvogo CE, Bella AL, Ellong A, Didier O, Eballe AO, Tambi FT. Surgical management of primary exotropia in Cameroon. Clin Ophthalmol 2007;1:471-4.
RESULTS
CONCLUSIONS
To report the outcomes of surgery on three horizontal muscles for very large-angle constant exotropia. In this prospective case series, consecutive adult patients with primary constant exotropia with angles $120D underwent strabismus surgery on three horizontal muscles. Surgery consisted of lateral rectus recession of 10–15 mm on the fixing eye in addition to lateral rectus recession of 9–13 mm and medial rectus resection of 6.5–9 mm on the nonfixing eye. The mean follow-up period was .6 months. Success was defined as horizontal esoor exodeviations of #10D. A total of 23 patients were included. The mean age at surgery was 30.4 9.3 years (range, 16-52). The mean preoperative near exodeviation was 128D 9.8D; the mean preoperative distance exodeviation, 130D 10.4D. The mean follow-up period was 8.1 1.4 months. At the last follow-up, 19 of the 23 cases (83%) were successfully aligned. At final follow-up examination, the mean postoperative exodeviation was 5D 4.2D (near) and 5D 4.3D (distance); no patient had diplopia on lateral gazes. In this patient cohort, surgery on three-muscle surgery for very large-angle exotropia successfully restored alignment in primary gaze in over 80% of cases without inducing symptomatic abduction deficits. ( J AAPOS 2013;17:578-581)
T
he best surgical approach for correcting very large-angle exotropia is still controversial. Lau and colleauges1 reported results of single-staged strabismus surgery on three horizontal muscles to restore primary position alignment for patients with large-angle exotropia (60D-85D) with no limitation of eye movement or diplopia. Recently, Chang and colleagues2 reported no significant symptomatic eye movement deficits after medial rectus resection of 9–11 mm and a lateral rectus muscle recession of 10–14 mm in 4 adults with sensory exotropia who had a mean deviation of 82D (range, 75D-90D). The purpose of the present study was to report the results of surgery on only three horizontal muscles to treat very large exotropias.
Patients and Methods This study was approved by the Shanxi Eye Hospital Ethics Committee and followed the tenets of the Declaration of Helsinki. Consecutive patients with primary extra-large angle exotropia ($120D at near and distance) undergoing strabismus surgery at
Author affiliations: Shanxi Eye Hospital, Shanxi Medical University, Taiyuan, China Submitted July 24, 2012. Revision accepted August 26, 2013. Published online November 7, 2013. Correspondence: Jun Hong Li, MD, PhD, Shanxi Eye Hospital, Shanxi Medical University, No.100 Fudong street, Taiyuan 030002, China (email: [email protected]). Copyright Ó 2013 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2013.07.015
578
Shanxi Eye Hospital from May 2011 to April 2012 were included. Patients with paralytic strabismus, a history of prior strabismus surgery, ocular comorbidities excepting refractive error and amblyopia, restricted eye movements, or strabismus with a secondary cause were excluded. The angle of deviation was measured by the alternate cover and prism test using single loose prisms 1D-80D. The 80D prism was routinely placed in front of one eye, while another of increasing strength was placed before the other eye until there was neutralization of eye movement. Prisms were stacked in front of one eye for exotropic deviations .140D. For example, we placed an 80D base-in prism in front of one eye and a 60D basein prism front of the other for 140D and placed an 80D base-in prism in front of one eye and a combined 60D base-in prism plus a 10D base-in prism in front of the other eye for 150D. This method of stacking prisms was not accurate and provided only a rough estimate of the preoperative deviation for deviations more than 140D. All patients underwent a complete ophthalmological examination before and after surgery. Forced duction test was performed in all patients before surgery. The preoperative distance deviation, surgical details, postoperative angle measurement at the last follow-up, postoperative abduction deficits of both eyes at the last follow-up, and length of follow-up were recorded (Table 1). Patients were reassessed at postoperative day 1, week 3, month 2, and every 2-3 months thereafter. All cases were followed for at least 6 months after surgery. Postoperative deviations with near and distance targets were measured by alternate prism and cover testing. Ductions and versions were measured at each follow-up examination.
Journal of AAPOS
Volume 17 Number 6 / December 2013
Li and Zhang
579
Table 1. Average surgical resultsa Surgery in nonfixing eye Pre-op dev 150 140 130 120
Post-op dev, PD
Number of cases
Surgery in fixing eye, mmb
LR recession, mm
MR resection, mm
2 6 5 10
15 13.8 12.8 10.3
12 11.7 10.8 9.6
8 8.3 7.6 7.4
Near 9 7.3 3.8 2.2
Distance
Abduction deficit Fixing eye, mm
11 7.3 3 3.3
1 1.2 0.6 0.7
Nonfixing eye, mm
Follow-up, months
2 1.8 1.6 1
7 8.8 8 7.9
Dev, deviation; LR, lateral rectus muscle; MR, medial rectus muscle; PD, prism diopters; Post-op, postoperative; Pre-op, preoperative. Negative values indicate exotropia for strabismus deviations. b LR recession. a
All operations were performed under topical anesthesia by one surgeon (JHL). A fornix approach was used for all muscles. The recession of the lateral rectus was performed with direct scleral fixation suture 10 mm from the insertion of the muscle combined with a hang-back suture using 6-0 polyglactin 910. All muscle recession and resection measurements were measured from the muscle insertion. All patients underwent surgery on three muscles, including lateral rectus recessions on the fixing eye and lateral rectus recession combined with medial rectus resection on the nonfixing eye. Some patients had adjustable sutures on all three muscles; sutures were adjusted at the time of surgery. In brief, bilateral lateral rectus recessions were performed and two slip knots were placed on the bilateral lateral rectus muscle. The medial rectus resection of 9 mm was then performed. The medial rectus muscle was recessed 1 mm from the original insertion in order to leave room for subsequent advancement. A slip knot was placed on the medial rectus muscle. The suture was tightened or loosened to change the eye position. After adjusting the medial rectus muscle resection, both lateral rectus muscle recessions were adjusted in order to achieve 10D of esotropia. After using adjustable sutures on all three muscles in the first 7 patients, a surgical dose for lateral rectus muscle recessions based on the preoperative deviation was established. The preoperative maximum abduction magnitude was measured by the corneal diameter minus the distance from the nasal limbus to the lateral canthus when the eye was maximally abducted. The lateral rectus muscle of the fixing eye was recessed a predetermined amount based on the preoperative deviation. Then the lateral rectus muscle of the nonfixing eye was recessed a predetermined amount based on the preoperative deviation and preoperative maximum abduction magnitude. The lateral rectus muscle of the fixing eye was recessed $1 mm if the preoperative maximum abduction magnitude of this eye was $ 13 mm for patients with 120D-140D exotropia (Table 2). Finally, the medial rectus muscle was resected on an adjustable suture for the remainder of the patients. The medial rectus muscle was then adjusted in order to achieve 10D of esotropia. Unilaterial or bilaterial inferior oblique recession or an upward transposition of the lateral rectus muscle of one-half tendon width and a downward transposition of the medial rectus of onehalf tendon width was performed for patients with V pattern. Successful motor alignment was defined as within 10D of exoor esodeviation.3
Journal of AAPOS
Table 2. Surgical doses for the lateral rectus muscle recessions based on the preoperative measurements Pre-op dev (distance), PDb 150 140 130 120
LR recession in fixing eye, mm
LR recession in nonfixing eye, mma
15 15 12 10
12 12-13c 11-12c 9-10c
Dev, deviation; LR, lateral rectus muscle; PD, prism diopters; Pre-op, preoperative. a In addition to medial rectus resection of 6.5–9 mm. b Negative values indicate exotropia for strabismus deviations. The dosing table was used for 16 patients in this study except 7 patients with all three muscles on an adjustable suture. c The lateral rectus muscle was recessed 1 mm more in the nonfixing eye if the preoperative maximum abduction magnitude of this eye was $3 mm for patients with 120D-140D of exotropia. Two patients had 150D of exotropia and received the same dose of lateral rectus recession on both nonfixing eyes. All measurements are reported as mean and standard deviation. SPSS 11.5 for Windows (SPSS Inc, Chicago, IL) was used for statistical analyses.
Results A total of 23 patients (12 males) were included. All patients had constant concomitant exotropia. The mean age at operation was 30.4 9.3 years old (range, 16-52 years old). All patients had best-corrected visual acuity .6/9 (Snellen) in each eye. The overall mean preoperative deviation was 128D 9.8D (range, 120D-150D) at near and 130D 10.4D (range, 120D-150D). Eight patients (35%) had a V pattern, with .15D greater exotropia inupthan downgaze. Forced duction testing revealed no restriction in any patient. Seven patients had all three muscles on an adjustable suture. The lateral rectus muscles were recessed a predetermined amount based on the preoperative deviation and maximum abduction magnitude (Table 2) followed, in 16 patients, by adjusting the medial rectus muscle resection on an adjustable suture. The mean follow-up period was 8.1 1.4 months (range, 6-10 months). The goal of 10D of esotropia was
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Volume 17 Number 6 / December 2013
FIG 1. A, Clinical photographs of 43-year-old woman with a constant concomitant exotropia of 150D before surgery. Right lateral rectus recession of 15 mm, left lateral rectus recession of 12 mm and left medial rectus resection of 8 mm were performed. B, Alignment in primary position alignment was successfully restored; the deficit of lateral rectus muscle was 2 mm in right eye and 3 mm in left eye at day 1 after surgery. Her upper eyelid had mild edema on left eye. C, The lateral rectus was almost full on right eye and the deficit of lateral rectus was 1 mm in left eye in 3 weeks after surgery. D, The lateral rectus muscle was almost full bilaterally in 7 months after surgery.
achieved in 19 patients (82.6%); there were no cases of overcorrection or consecutive esodeviations. All patients with residual deviations were exotropic. The overall mean near angle of postoperative exodeviation at the last follow-up was 5D 4.2D (range, 0D-13D), and was also 5D 4.3D (range, 0D-17D) at distance. In 4 patients (17.4%) there was an esotropia of 3D-8D after adjustment. The mean lateral rectus recession performed was 12.2 2.0 mm (range, 10-15 mm) on fixing eyes. The mean lateral rectus recession was 10.6 21.3 mm (range, 9–13 mm) and the mean medial rectus resection performed was 7.7 0.6 mm (range, 6.5–9 mm) on nonfixing eyes. The mean surgical dosage is listed in Table 1. The limitation of abduction resulting from bilateral lateral rectus supramaximal recession procedure was significant immediately after surgery and only on the day of surgery. Limitation of abduction significantly improved on postoperative day 1 (Figure 1) and recovered gradually over time. The abduction of the lateral rectus muscle with a supramaximal recession was almost full 3 weeks postoperatively in most cases (Figures 1-2). The mean deficit of lateral rectus abduction using the method described above was 0.8 0.7 mm (range, 0–2 mm) in the fixing eye and 1.3 0.7 mm (range, 0–3 mm) in the nonfixing eye at the last follow-up. There was no symptomatic postoperative eye movement deficit in any patient at final follow-up.
None of the patients demonstrated binocular function either before or after surgery, and none experienced diplopia in primary gaze postoperatively. Two patients had diplopia on extreme lateral gazes. Their diplopia had resolved by 3 weeks after surgery. Of the 23 cases, 22 (95.7%) were satisfied with their cosmetic appearances at final follow-up. One patient required a second medial rectus resection of 5 mm on the fixing eye for 17D of residual exotropia. The second operation was successful.
Discussion The main goal of surgery in patients with large-angle exotropia without binocular function should be improved alignment in primary gaze, with a secondary goal of a normal range of duction in each eye. This study reports the surgical results of our current surgical technique of operating on only three horizontal muscles to treat very large-angle exotropia. The technique successfully treated 19 or 23 patients in this Chinese cohort without inducing symptomatic abduction deficits. Surgeries involving two, three, or four muscles have been reported for treatment of very large-angle exotropia has been reported.1-3 Berland and colleagues4 reported a success rate of 80% with 8–9 mm bilateral lateral rectus recession, but with abduction limitations in 30% of the
Journal of AAPOS
Volume 17 Number 6 / December 2013
Li and Zhang
581
FIG 2. A, Clinical photographs of a 36-year-old woman with 130D constant concomitant exotropia before surgery. Left lateral rectus recession of 12 mm, right lateral rectus recession of 11 mm and right medial rectus resection of 7 mm were performed. B, Both eyes were straight in primary position and the deficit of lateral rectus muscle was 2 mm in the right eye and 1 mm in the left eye 18 days after surgery.
24 patients studied. Some studies of large-angle exotropia have reported success rates ranging from 70% to 80% in bilateral lateral rectus recessions, without significant abduction limitations.1-2,5-9 Lau and colleagues1 reported a 70% success rate with 24 patients with a mean angle of deviation of 71.5D who underwent single-stage threemuscle surgery that consisted of bilateral lateral rectus recession of 9 mm for 50D and unilateral medial rectus resection of 1 mm for every 5D remaining angle. No significant postoperative abduction deficit was noted in any patient. Chang and colleagues2 found that there was no significant symptomatic postoperative eye movement deficit after a medial rectus muscle resection of 9–11 mm and a lateral rectus muscle recession 10–14 mm in 4 adult sensory exotropia patients with a mean deviation of 82.3D. Exotropia deviations .120D in adults are common in China but rare in the West. There has been little literature addressing the results of constant exotropia of $ 120D. Like Chang and colleagues,2 we found no symptomatic postoperative eye movement deficit in any of our patients at final follow-up. The limitation of abduction resulting from the lateral rectus supramaximal recession procedure was notable immediately after surgery but improved quickly. In all subjects, the postoperative alignment drifted toward exotropia and the abduction improved as the lateral rectus muscle healed. It is possible that the lateral rectus muscle “crept” forward, accounting for the improvement in abduction and the return of exotropia. In our data, the nonfixing eye had a greater abduction deficiency than the fixing eye. This might be because the nonfixing eye simultaneously underwent large medial rectus resection, perhaps temporarily increasing the resistance of the medial rectus muscle to abduction.
Journal of AAPOS
One patient in our study underwent a secondary surgery because she was not satisfied with her undercorrection. The medial rectus resection in the fixing eye was performed for this residual exotropia. We think that keeping an intact or untouched muscle is good for the complication of undercorrection after three-muscle surgeries. This study limited by the fact that our postoperative measurements of the deviations in the primary position and the abduction deficit were unmasked. Although our technique did not create a large abduction deficit in either eye, measurements of the eye alignment in eccentric gaze would be helpful to better quantify the effects in eccentric gaze. References 1. Lau FH, Fan DS, Yip WW, Yu CB, Lam DS. Surgical outcome of single-staged three horizontal muscles squint surgery for extra-large angle exotropia. Eye 2010;24:1171-6. 2. Chang JH, Kim HD, Lee JB, Han SH. Supermaximal recession and resection in large-Angle sensory exotropia. Korean J Ophthalmol 2011;25:139-41. 3. Livir-Rallatos G, Gunton KB, Calhoun JH. Surgical results in largeangle exotropia. J AAPOS 2002;6:77-80. 4. Berland JE, Wilson ME, Saunders RB. Results of large (8–9 mm) bilateral lateral rectus muscle recessions for exotropia. Binocul Vis Strabismus Q 1998;13:97-104. 5. Celebi S, Kukner AS. Large bilateral lateral rectus recession in large angle divergence excess exotropia. Eur J Ophthalmol 2001;11:6-8. 6. Currie ZI, Shipman T, Burke JP. Surgical correction of large-angle exotropia in adults. Eye 2003;17:334-9. 7. Rayner JW, Jampolsky A. Management of adult patients with large angle exotropia and amblyopia. Ann Ophthamol 1973;5:95-9. 8. Schwartz RL, Calhoun JH. Surgery of large angle exotropia. J Pediatr Ophthalmol Strabismus 1980;17:359-63. 9. Mvogo CE, Bella AL, Ellong A, Didier O, Eballe AO, Tambi FT. Surgical management of primary exotropia in Cameroon. Clin Ophthalmol 2007;1:471-4.