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Strabismus surgery outcomes without removal of scleral buckle in patients with previous retinal detachment repair
Major Article Strabismus surgery outcomes without removal of scleral buckle in patients with previous retinal detachment repair Carla J. Osigian, MD,a Lindsay Rothfield, BS,a Gilad Rabina, MD,b Kara M. Cavuoto, MD,a Oriel Spierer, MD,b Elizabeth A. Vanner, MS, PhD,a and Hilda Capo, MDa PURPOSE METHODS
RESULTS
CONCLUSIONS
To report the motor and sensory outcomes of strabismus surgery following scleral buckle procedure for retinal detachment (RD) without removal of the scleral buckle. The medical records of patients who underwent strabismus surgery without removal of scleral buckle following RD surgical repair at a tertiary referral center between 2002 and 2015 were reviewed retrospectively. Demographic data were recorded, and rates of surgical motor success (defined as horizontal deviation of #10D and vertical deviation of #4D) and sensory success (resolution of diplopia) were calculated. A total of 23 patients (mean age, 58.4 24.4 years; 12 males) were included. The average time between the RD surgery and onset of strabismus was 11.05 10.95 months (range, 142 months). The strabismus was horizontal in 6 patients, vertical in 2, and combined in 15. Eighteen patients (78%) presented with diplopia. Adjustable sutures were used in 18 patients. Final motor surgical success was achieved in 17 of 23 patients (74%), and diplopia improved in 17 of 18 patients (94%) who had preoperative fusional capability. There was no statistically significant difference in age, number of RD surgeries, macular status, time to strabismus surgery, visual acuity in the worse eye, or magnitude of preoperative horizontal and vertical deviation with regard to motor success rate and with persistence of diplopia postoperatively. In our study cohort, strabismus surgery without removal of the scleral buckle resulted in motor success and alleviated diplopia in the majority of patients with prior RD repair. ( J AAPOS 2018;-:1-4)
T
he use of scleral buckles to repair retinal detachments (RDs) has been shown to cause ocular motility disorders. Postoperative strabismus develops in 3.8%-25% of cases1,2; diplopia, in 3%-73% of patients.2-4 The cause of strabismus in these patients is often multifactorial. Etiologies include sensory factors, such as poor vision due to macular damage, myotoxicity from peribulbar/retrobulbar anesthesia, and mechanical disturbances related to the scleral buckle (eg, direct intraoperative muscle damage, fibrosis, scarring and
Author affiliations: aBascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida; bOphthalmology Division, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Presented as a poster at the 43rd Annual Meeting of the American Association for Pediatric Ophthalmology and Strabismus, Nashville, Tennessee, April 2-6, 2017. Submitted October 13, 2017. Revision accepted April 1, 2018. Correspondence: Hilda Capo, MD, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Department of Ophthalmology, 900 NW 17th St, Miami, Florida, 33136 (email: [email protected]). Copyright Ó 2018, American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved. 1091-8531/$36.00 https://doi.org/10.1016/j.jaapos.2018.04.004
Journal of AAPOS
adhesions between the muscle, sclera, fat, and scleral buckle, mass effect of the underlying scleral buckle, and muscle displacement).2,5 Surgical treatment of strabismus in eyes with scleral buckle poses challenges. Successful motor outcomes, ranging from 47% to 80%, have been reported,2,4,6 with successful sensory outcomes in up to 62% of patients.2 However, whether or not removal of the scleral buckle improves ocular alignment is still debated. Some authors suggest that scleral buckle removal eliminates the mechanical factors implicated in muscular imbalance4; however, removal of the scleral buckle has also been associated with redetachment of the retina in 4% to 33% of cases.7,8 The purpose of this study was to report the motor and sensory outcomes of strabismus surgery following RD repair without scleral buckle removal at a single center over a 14-year period.
Subjects and Methods This study was approved by the University of Miami Institutional Review Board, adhered to the tenets of the Declaration of Helsinki, and complied with the US Health Insurance Portability and Accountability Act of 1996. The medical records of patients
1
2
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who underwent strabismus surgery following RD surgical repair at Bascom Palmer Eye Institute between 2002 and 2015 were reviewed retrospectively. Financial claims data were searched to identify patients who underwent RD surgical repair with scleral buckle with and without pars plana vitrectomy (Current Procedural Terminology-4 67107, 67108, 67110, 67112) as well as extraocular muscle surgery (Current Procedural Terminology-4 67311, 67312, 67314, 67316). Surgeries were performed by 3 pediatric ophthalmologists (HC, KMC, CAM). All scleral buckles were left in place, provided there was no extrusion or infection. Intraoperatively, the scleral buckle was not deliberately avoided during surgery. When the scleral buckle was encountered, the surgeon released any adhesions between the muscle and the scleral buckle and performed the intended procedure. The muscle was reattached to the globe at the insertion for resections and suspended over the buckle with hang-back or adjustable sutures for recessions. Patients that required scleral buckle removal prior to strabismus surgery for extrusion or infection were excluded, as were patients with concomitant ocular morbidities that could cause strabismus (such as glaucoma drainage devices and thyroid ophthalmopathy) and those with \6 weeks postoperative follow-up. The following data were extracted from the medical record: age, sex, pre- and postoperative visual acuity, previous RD repair procedures, timing of strabismus or diplopia onset after RD repair based on patient’s report, pre- and postoperative ocular alignment in primary gaze, limitation of ductions in the affected eye, pre- and postoperative presence of diplopia, type of strabismus surgery performed, intra- and postoperative complications, use of adjustable suture technique, and length of postoperative follow-up. Torsion, stereopsis, ocular alignment in different gaze positions, forced duction testing, and types of scleral buckles were not analyzed, because documentation in medical records was inconsistent. Ocular alignment in primary position was measured by alternate prism cover testing or by Krimsky testing in patients with a best-corrected visual acuity of #20/200. The postoperative surgical results were described as motor and sensory outcomes. Surgical motor success was defined in all patients as postoperative horizontal deviation of #10D and vertical deviation #4D in primary position of gaze. In patients that presented with diplopia preoperatively, sensory success was defined as intermittent or constant resolution of diplopia in primary gaze with or without prism glasses. In patients without preoperative sensory complaints or diplopia, only postoperative surgical motor success was evaluated.
Statistical Analysis Statistical analysis was performed with SAS software version 9.4 (Cary, NC). Correlations between motor success rate and age, visual acuity, number of previous retina surgeries, macular involvement, and preoperative deviation were determined using the Fisher exact test for categorical variables. Continuous variables were tested for a normal distribution. For non-normally distributed variables, groups were compared using the MannWhitney-Wilcoxon two-sample nonparametric test. For normally distributed variables, groups were compared using an
independent samples t test, assuming equal or unequal variance, as appropriate. Snellen best-corrected visual acuity results were converted to logMAR values for analysis.
Results A total of 23 patients (12 males [52%]) who underwent strabismus surgery after RD repair with scleral buckle were included. Mean age at surgery was 58.4 24.4 years (range, 12-81 years), including 3 pediatric patients with RD due to acute retinal necrosis or trauma. Patient characteristics, including pre- and postoperative sensorimotor examinations, are highlighted in eTable 1. Eleven patients (48%) required 2 or more RD repair surgeries prior to strabismus surgery. The macula was affected in 20 patients (87%). The average time between the last RD repair surgery and the onset of strabismus and/or diplopia was 11.05 10.95 months (range, 1-42 months). The average time between the last retinal repair surgery and strabismus surgery was 22.17 15.81 months (range, 6-63 months). Strabismus was horizontal in 6 patients, vertical in 2, and combined horizontal and vertical in 15. In the last group, the vertical component was addressed by horizontal muscle supra- or infraplacement in 3 patients and concurrent horizontal and vertical muscle surgery in 4. In 8 patients the surgical approach was tailored to address only the deviation most visually apparent to the patient (horizontal in 6 and vertical in 2), because the accompanying deviation was either of very small magnitude or present intermittently. Preoperative horizontal deviations addressed surgically ranged from esotropia of 40D to exotropia of 60D (mean magnitude [absolute value], 27.9D 11.6D); vertical deviations, from 8D to 25D (mean magnitude, 13.1D 4.9D). Preoperatively, 18 patients (78%) presented with diplopia. Of the 5 patients without diplopia, 4 had sensory exotropia (best-corrected visual acuity of #20/400) and 1 had a long-standing large-angle exotropia, which likely enabled the patient not to experience diplopia. A retina specialist confirmed that the retina was attached prior to strabismus surgery. Twenty-one patients (91%) underwent surgery in the same eye as the scleral buckle; 2 underwent surgery in the contralateral eye with lower best-corrected visual acuity. Eighteen patients (78%) underwent strabismus surgery using an adjustable suture technique, of whom 5 patients required postoperative adjustment consisting of re-recessions of 1–3 mm (mean, 2 mm). In these patients, although the position of the buckle was considered during postoperative adjustment, there is a chance that in some cases the muscle may have healed onto the silicone band. Two patients (9%) underwent a second operation. The mean postoperative followup was 9.2 11.9 months (range, 2-36 months). Alignment Outcomes Surgical success was achieved in 16 patients (70%) after the first surgery and in 17 (74%) after two surgeries. Motor
Journal of AAPOS
Volume - Number - / - 2018 surgical success was achieved in 15 of 21 patients (71%) with surgery on the eye with the scleral buckle and in both patients with surgery on the contralateral eye. The patient’s age (P 5 0.35), number of RD surgeries (P 5 0.73), time to strabismus surgery (P 5 0.70), bestcorrected visual acuity in the worse eye (P 5 0.73), macular status (P 5 0.15), or magnitude of preoperative horizontal (P 5 0.19) or vertical deviation (P 5 0.32) addressed surgically were not statistically significantly different in those with and without a successful motor outcome. Sensory Outcomes Of the 18 patients with diplopia and preoperative fusional capability, 17 (94%) reported subjective improvement of diplopia after surgery in primary position at distance and near. Of these, 6 experienced complete resolution of diplopia. Of the 12 patients (67%) with some degree of postoperative diplopia, 4 could fuse intermittently, 7 fused with a Fresnel or ground-in prism, and 1 continued to have constant diplopia. In these cases of complex strabismus, the authors considered postoperative sensory success to be intermittent fusion in primary gaze, although some patients may have had residual diplopia in eccentric positions of gaze. In 14 of these 18 patients (78%) with preoperative fusional capability, postoperative motor outcome was successful. Five of these 14 patients (36%) had complete resolution of diplopia and 9 (64%) continued to experience some postoperative diplopia, including the patient with constant postoperative diplopia. The patient’s age (P 5 1.00), number of RD surgeries (P 5 0.46), time to strabismus surgery (P 5 0.74), best-corrected visual acuity in the worse eye (P 5 0.31), macular status (P 5 0.36), and magnitude of preoperative horizontal (P 5 0.23) and vertical deviation (P 5 0.52) were not statistically significantly different for those who did and did not have some degree of postoperative diplopia after a successful motor outcome.
Discussion The reported success rates of strabismus surgeries after scleral buckle surgery are lower than those of noncomplex strabismus surgeries. In our study cohort 74% of patients with strabismus after scleral buckle procedure achieved successful alignment after strabismus surgery without scleral buckle removal. These results agree with those of several previous studies showing success rates ranging from 47% to 80%.2,5,6,9-11 However, our results are based on a short follow-up time, because many patients continued care with their primary retina or general ophthalmologist after 2 months. The variable success rates are likely attributed to the wide range of causes of strabismus after scleral buckle surgery, including direct muscle injury, myotoxicity from peribulbar/retrobulbar anesthetic injection, scleral dissection, interference with muscle function by the scleral buckle, scarring of Tenon’s capsule, and orbital fat adhesions.1,12-15 Disturbance in fusional ability
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may also induce strabismus. Fusion may be lost because of poor visual acuity following RD or anisometropia from the myopic shift caused by axial elongation by the scleral buckle.5,16-18 In some cases the mechanism is multifactorial, which may explain the high rate of combined horizontal and vertical strabismus reported in this case series (65%) as well as in other studies.2,10,16,18-20 Because the standard strabismus surgical dose tables may not be as reliable for these complex cases, adjustable sutures may be beneficial. Adjustable sutures were used in 18 patients (78%), 5 of whom required postoperative adjustment. Success at last follow-up was achieved in 72% of the adjusted patients. The timing of strabismus onset varies. Previous studies have shown that some patients develop strabismus and diplopia in the immediate postoperative period, whereas others develop it months or even years after the RD surgery.2,10 In our series, the onset of strabismus ranged from 1 month to 3.5 years. It is possible that the time of onset of strabismus may depend on the responsible mechanism. A myotoxic effect or direct damage to the muscle may cause strabismus immediately after scleral buckle surgery, whereas mechanical factors may occur weeks or months after surgery as scarring develops.16,20 A sensory deviation can also develop months after vision is lost. In patients with strabismus, diplopia may be influenced by both the degree of deviation and by visual acuity. Because most of our patients had a visual acuity of .20/ 400, 78% reported diplopia preoperatively. This is consistent with rates of postoperative diplopia reported by Spencer and colleagues (72%)21 and Rabinowitz and colleagues (100%).2 It has been reported that some patients may continue to experience diplopia postoperatively even after a successful postoperative motor outcome is achieved. Rabinowitz and colleagues reported that 8 of their patients (38%) experienced residual diplopia, of whom 4 had motor success at final follow-up.2 In our study, diplopia persisted in 9 patients despite a successful motor outcome. Because these were usually low-magnitude angles of deviation (\10D, eTable 1), all patients except one were able to fuse intermittently or with prismatic correction. Scleral buckle removal without strabismus surgery has been attempted as a means to alleviate diplopia, but diplopia persisted in the majority of patients (80%100%).4,7,19,22 Although Chang and colleagues6 reported a 62.5% success rate with scleral buckle removal during strabismus surgery compared to 10% without scleral buckle removal,6 Rabinowitz and colleagues2 found no difference. Other studies suggest that the removal of the scleral buckle would not necessarily have a positive effect on the strabismus outcome and therefore should be only considered if the scleral buckle itself seems to be related to the deviation.4,9,19 In our practice, we usually do not remove the scleral buckle. Because our motor success rates (70% for the first surgery and 74% for the second
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surgery) are on the higher end of reported results, we believe that scleral buckle removal is not necessary to achieve a good postoperative outcome. In addition, studies have shown that scleral buckle removal might expose patients to a risk of redetachment, which has been reported to range from 4% to 33%.7,8 Approximately 50% of our patients presenting with strabismus after RD repair have already required multiple previous RD surgeries because of redetachments. Therefore, we prefer to leave the scleral buckle intact and only remove in select cases with prior approval of the retina surgeon. This study has several limitations including the relatively small number of patients, its retrospective nature, and the lack of complete data for all patients. In addition, data regarding the scleral buckle type, size, and orientation was not available. Nevertheless, our results indicate that motor success and symptomatic improvement of diplopia may be achieved without scleral buckle removal.
Acknowledgments The authors acknowledge the contribution of Craig A. McKeown, MD, Bascom Palmer Eye Institute, in the form of patient recruitment and discussion of scientific content. References 1. Wolff SM. Strabismus after retinal detachment surgery. Trans Am Ophthalmol Soc 1983;81:182-92. 2. Rabinowitz R, Velez FG, Pineles SL. Risk factors influencing the outcome of strabismus surgery following retinal detachment surgery with scleral buckle. J AAPOS 2013;17:594-7. 3. Kasbekar SA, Wong V, Young J, Stappler T, Durnian JM. Strabismus following retinal detachment repair: a comparison between scleral buckling and vitrectomy procedures. Eye (Lond) 2011;25:1202-6. 4. Fison PN, Chignell AH. Diplopia after retinal detachment surgery. Br J Ophthalmol 1987;71:521-5. 5. Chaudhry NL, Durnian JM. Post-vitreoretinal surgery strabismus-a review. Strabismus 2012;20:26-30.
6. Chang JH, Hutchinson AK, Zhang M, Lambert SR. Strabismus surgery outcomes after scleral buckling procedures for retinal reattachment. Strabismus 2013;21:235-41. 7. Schwartz PL, Pruett RC. Factors influencing retinal redetachment after removal of buckling elements. Arch Ophthalmol 1977;95:804-7. 8. Moisseiev E, Fogel M, Fabian ID, Barak A, Moisseiev J, Alhalel A. Outcomes of scleral buckle removal: experience from the last decade. Curr Eye Res 2017;42:766-70. 9. Mu~ noz M, Rosenbaum AL. Long-term strabismus complications following retinal detachment surgery. J Pediatr Ophthalmol Strabismus 1987;24:309-14. 10. Ganekal S, Nagarajappa A. Strabismus following scleral buckling surgery. Strabismus 2016;24:16-20. 11. Seaber JH, Buckley EG. Strabismus after retinal detachment surgery: etiology, diagnosis, and treatment. Semin Ophthalmol 1995;10:61-73. 12. Arruga A. Motility disturbances induced by operations for retinal detachment. Mod Probl Ophthalmol 1977;18:408-14. 13. Wright KW. The fat adherence syndrome and strabismus after retina surgery. Ophthalmology 1986;93:411-15. 14. Cooper LL, Harrison S, Rosenbaum AL. Ocular torsion as a complication of scleral buckle procedures for retinal detachments. J AAPOS 1998;2:279-84. 15. Salama H, Farr AK, Guyton DL. Anesthetic myotoxicity as a cause of restrictive strabismus after scleral buckling surgery. Retina 2000;20: 478-82. 16. Smiddy WE, Loupe D, Michels RG, Enger C, Glaser BM, de Bustros S. Extraocular muscle imbalance after scleral buckling surgery. Ophthalmology 1989;96:1485-9. 17. Kutschera E, Antlanger H. Influence of retinal detachment surgery on eye motility and binocularity. Mod Probl Ophthalmol 1979;20:354-8. 18. Maurino V, Kwan A, Khoo BK, Gair E, Lee JP. Ocular motility disturbances after surgery for retinal detachment. J AAPOS 1998;2: 285-92. 19. Wong V, Kasbekar S, Young J, Stappler T, Marsh IB, Durnian JM. The effect of scleral exoplant removal on strabismus following retinal detachment repair. J AAPOS 2011;15:331-3. 20. Farr AK, Guyton DL. Strabismus after retinal detachment surgery. Curr Opin Ophthalmol 2000;11:207-10. 21. Spencer AF, Newton C, Vernon SA. Incidence of ocular motility problems following scleral buckling surgery. Eye (Lond) 1993;7:751-6. 22. Deokule S, Reginald A, Callear A. Scleral explant removal: the last decade. Eye (Lond) 2003;17:697-700.
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4.e1
Success
Followup, mos
eTable 1. Pre- and postoperative patient characteristics Deviation, PD BCVA in operated Patient eye
Pre-op Surgery
Adjusted
2 3
L-LR rec 8 mm adj No L-MR res 6 mm SP 2 mm NLP L-LR rec 12 mm N/A 20/200 L-IR rec 5 mm adj No
4
20/25
1
5 6
7 8 9 10 11 12
13 14 15 16 17 18 19 20 21
22 23
20/60
L-LR rec 8 mm adj L-SR rec 7 mm adj 20/60 R-LR rec 8 mm adj R-MR res 6.5 mm 20/50 #1 R-SR rec 4 mm adj R-IR res 3 mm #2 R-IO myectomy 5 mm R-IR res 4 mm adj 20/60 L-LR rec 5.5 mm 20/40 L-LR rec 8 mm adj L-MR res 5 mm IP 2 mm 20/150 R-MR rec 7 mm 20/350 L-MR rec 7 mm adj
H
Post-op V
H
V
Pre-op
Post-op
Motor
Sensory
45 L-XTa 8 L-HoTa
6 L-XT
5 L-HoT Yes
No
No
Yes
2
35 L-XTa
15 L-XT
No 12 L-HoT Yes
No Yes: Fresnel prism Yes: Fresnel prism No
No No
N/A Nob
2 12
No
Nob
2
No
N/A
3
14 L-HoTa
No
18 L-XTa 16 L-HTa
Re-rec 2 mm No
60 R-XTa 10 R-HoT 25 R-XT 6 R-HoT No
N/A No
25 L-XTa 4 L-HT 25 L-XTa 8 L-HTa
8 L-XT 4 XT
N/A No
25 R-ETa 4 R-HT 30 L-ETa
4 R-E(T) 6 L-E(T)
20 L-XT 18 L-HT Yes
25 R-HTa
20/250 L-IR rec 4.5 mm adj Re-rec 6 L-XT 1 mm 20/60 L-SR rec 3 mm adj L-SR re-rec 10 L-XTa L-LR rec 5 mm adj 3 mm L-LR Re-rec 3 mm CF 3 ft LLR rec 10 mm N/A 20 L-XTa 20/40 RLR rec adj No 30 R-XTa RMR adv 20/70 LMR rec 3.5 mm adj L-MR re-rec 16 L-ETa LIR rec 4.5 mm adj 1 mm 20/40c LIR rec 5.5 mm adj L-IR re-rec 2 20 R-XTa LLR rec 9 mm adj LP RLR rec 8 mm N/A 30 R-XTa RMR res 6 mm 16 L-XTa 20/30c RLR rec 10 mm adj No 20/20 RSR rec adj 20/100 RMR rec 6 mm adj RLR res 4 mm and adv 4 mm 20/250 #1 LMR rec 2 mm adj LLR adv 4 mm #2 LMR rec 4 mm adj 20/80 RLR rec 5.5 mm adj RMR res 4.5 mm 20/400 RLR rec 11 mm adj SP 3 mm
Diplopia
14 L-HoTa 4 L-XT
7 R-HT
Yes
Yes: ground-in No prism
Nob
36
4 L-HT
Yes Yes
Intermittent Intermittent
Yes Yes
Nob Nob
2 2
Yes Yes
No Yes Yes: ground-in Yes prism Yes Yes
Yes Nob
10 9
3 L-HoT Yes
No; constant diplopia Nob
2
12 L-HTa
8 L-X(T) 4 L-H(T) Yes
Yes: ground-in Yes prism
10 L-HT
Ortho Ortho
No Yes
No No
Yes Yes
N/A Yes
2 2
14 L-HoTa
2 L-HoT Yes
No
Yes
Yes
36
15 R-HTa 8 L-XT
4 R-HT
Yes
Yes
Nob
2
Ortho
No
Yes: Fresnel prism No
Yes
N/A
2
Ortho 3 L-HT
10 L-XT 2 R-HT
Yes
32
Yes
Nob
3
Yes Yes
Nob Yes
31 9
No No
10 R-X(T) 10 R-H(T)a 10 R-XT 40 R-ETa 2 R-E(T)
Yes Yes
Yes: Fresnel prism Intermittent No
No
30 L-ETa
Ortho
Yes
No
Yes
Yes
6
No
30 R-XTa 5 R-HT
4 R-X(T) 3 R-H(T) Yes
Intermittent
Yes
Nob
2
No
25 R-XTa 8 R-HoTa 6 R-XT 2 R-HoT No
No
Yes
N/A
2
Adj, adjustable; Adv, advancement; BCVA, best-corrected visual acuity; ET, esotropia; H, horizontal; HoT, hypotropia; HT, hypertropia; H(T), intermittent hypertropia; IO, inferior oblique muscle; IP, infraplacement; L, left; IR, inferior rectus muscle; LR, lateral rectus muscle; MR, medial rectus muscle; N/A, not applicable; PD, prism diopter; R, right; Rec, recession; Re-rec, re-recession; Res, resection; RET, right esotropia; SP, supraplacement; SR, superior rectus muscle; V, vertical; XT, exotropia; X(T), intermittent exotropia. a Deviation addressed in surgical procedure. b No motor success but subjective improvement. c Patients in whom strabismus surgery was performed on the eye without scleral buckle.
Journal of AAPOS
RESULTS
CONCLUSIONS
To report the motor and sensory outcomes of strabismus surgery following scleral buckle procedure for retinal detachment (RD) without removal of the scleral buckle. The medical records of patients who underwent strabismus surgery without removal of scleral buckle following RD surgical repair at a tertiary referral center between 2002 and 2015 were reviewed retrospectively. Demographic data were recorded, and rates of surgical motor success (defined as horizontal deviation of #10D and vertical deviation of #4D) and sensory success (resolution of diplopia) were calculated. A total of 23 patients (mean age, 58.4 24.4 years; 12 males) were included. The average time between the RD surgery and onset of strabismus was 11.05 10.95 months (range, 142 months). The strabismus was horizontal in 6 patients, vertical in 2, and combined in 15. Eighteen patients (78%) presented with diplopia. Adjustable sutures were used in 18 patients. Final motor surgical success was achieved in 17 of 23 patients (74%), and diplopia improved in 17 of 18 patients (94%) who had preoperative fusional capability. There was no statistically significant difference in age, number of RD surgeries, macular status, time to strabismus surgery, visual acuity in the worse eye, or magnitude of preoperative horizontal and vertical deviation with regard to motor success rate and with persistence of diplopia postoperatively. In our study cohort, strabismus surgery without removal of the scleral buckle resulted in motor success and alleviated diplopia in the majority of patients with prior RD repair. ( J AAPOS 2018;-:1-4)
T
he use of scleral buckles to repair retinal detachments (RDs) has been shown to cause ocular motility disorders. Postoperative strabismus develops in 3.8%-25% of cases1,2; diplopia, in 3%-73% of patients.2-4 The cause of strabismus in these patients is often multifactorial. Etiologies include sensory factors, such as poor vision due to macular damage, myotoxicity from peribulbar/retrobulbar anesthesia, and mechanical disturbances related to the scleral buckle (eg, direct intraoperative muscle damage, fibrosis, scarring and
Author affiliations: aBascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida; bOphthalmology Division, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Presented as a poster at the 43rd Annual Meeting of the American Association for Pediatric Ophthalmology and Strabismus, Nashville, Tennessee, April 2-6, 2017. Submitted October 13, 2017. Revision accepted April 1, 2018. Correspondence: Hilda Capo, MD, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Department of Ophthalmology, 900 NW 17th St, Miami, Florida, 33136 (email: [email protected]). Copyright Ó 2018, American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved. 1091-8531/$36.00 https://doi.org/10.1016/j.jaapos.2018.04.004
Journal of AAPOS
adhesions between the muscle, sclera, fat, and scleral buckle, mass effect of the underlying scleral buckle, and muscle displacement).2,5 Surgical treatment of strabismus in eyes with scleral buckle poses challenges. Successful motor outcomes, ranging from 47% to 80%, have been reported,2,4,6 with successful sensory outcomes in up to 62% of patients.2 However, whether or not removal of the scleral buckle improves ocular alignment is still debated. Some authors suggest that scleral buckle removal eliminates the mechanical factors implicated in muscular imbalance4; however, removal of the scleral buckle has also been associated with redetachment of the retina in 4% to 33% of cases.7,8 The purpose of this study was to report the motor and sensory outcomes of strabismus surgery following RD repair without scleral buckle removal at a single center over a 14-year period.
Subjects and Methods This study was approved by the University of Miami Institutional Review Board, adhered to the tenets of the Declaration of Helsinki, and complied with the US Health Insurance Portability and Accountability Act of 1996. The medical records of patients
1
2
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who underwent strabismus surgery following RD surgical repair at Bascom Palmer Eye Institute between 2002 and 2015 were reviewed retrospectively. Financial claims data were searched to identify patients who underwent RD surgical repair with scleral buckle with and without pars plana vitrectomy (Current Procedural Terminology-4 67107, 67108, 67110, 67112) as well as extraocular muscle surgery (Current Procedural Terminology-4 67311, 67312, 67314, 67316). Surgeries were performed by 3 pediatric ophthalmologists (HC, KMC, CAM). All scleral buckles were left in place, provided there was no extrusion or infection. Intraoperatively, the scleral buckle was not deliberately avoided during surgery. When the scleral buckle was encountered, the surgeon released any adhesions between the muscle and the scleral buckle and performed the intended procedure. The muscle was reattached to the globe at the insertion for resections and suspended over the buckle with hang-back or adjustable sutures for recessions. Patients that required scleral buckle removal prior to strabismus surgery for extrusion or infection were excluded, as were patients with concomitant ocular morbidities that could cause strabismus (such as glaucoma drainage devices and thyroid ophthalmopathy) and those with \6 weeks postoperative follow-up. The following data were extracted from the medical record: age, sex, pre- and postoperative visual acuity, previous RD repair procedures, timing of strabismus or diplopia onset after RD repair based on patient’s report, pre- and postoperative ocular alignment in primary gaze, limitation of ductions in the affected eye, pre- and postoperative presence of diplopia, type of strabismus surgery performed, intra- and postoperative complications, use of adjustable suture technique, and length of postoperative follow-up. Torsion, stereopsis, ocular alignment in different gaze positions, forced duction testing, and types of scleral buckles were not analyzed, because documentation in medical records was inconsistent. Ocular alignment in primary position was measured by alternate prism cover testing or by Krimsky testing in patients with a best-corrected visual acuity of #20/200. The postoperative surgical results were described as motor and sensory outcomes. Surgical motor success was defined in all patients as postoperative horizontal deviation of #10D and vertical deviation #4D in primary position of gaze. In patients that presented with diplopia preoperatively, sensory success was defined as intermittent or constant resolution of diplopia in primary gaze with or without prism glasses. In patients without preoperative sensory complaints or diplopia, only postoperative surgical motor success was evaluated.
Statistical Analysis Statistical analysis was performed with SAS software version 9.4 (Cary, NC). Correlations between motor success rate and age, visual acuity, number of previous retina surgeries, macular involvement, and preoperative deviation were determined using the Fisher exact test for categorical variables. Continuous variables were tested for a normal distribution. For non-normally distributed variables, groups were compared using the MannWhitney-Wilcoxon two-sample nonparametric test. For normally distributed variables, groups were compared using an
independent samples t test, assuming equal or unequal variance, as appropriate. Snellen best-corrected visual acuity results were converted to logMAR values for analysis.
Results A total of 23 patients (12 males [52%]) who underwent strabismus surgery after RD repair with scleral buckle were included. Mean age at surgery was 58.4 24.4 years (range, 12-81 years), including 3 pediatric patients with RD due to acute retinal necrosis or trauma. Patient characteristics, including pre- and postoperative sensorimotor examinations, are highlighted in eTable 1. Eleven patients (48%) required 2 or more RD repair surgeries prior to strabismus surgery. The macula was affected in 20 patients (87%). The average time between the last RD repair surgery and the onset of strabismus and/or diplopia was 11.05 10.95 months (range, 1-42 months). The average time between the last retinal repair surgery and strabismus surgery was 22.17 15.81 months (range, 6-63 months). Strabismus was horizontal in 6 patients, vertical in 2, and combined horizontal and vertical in 15. In the last group, the vertical component was addressed by horizontal muscle supra- or infraplacement in 3 patients and concurrent horizontal and vertical muscle surgery in 4. In 8 patients the surgical approach was tailored to address only the deviation most visually apparent to the patient (horizontal in 6 and vertical in 2), because the accompanying deviation was either of very small magnitude or present intermittently. Preoperative horizontal deviations addressed surgically ranged from esotropia of 40D to exotropia of 60D (mean magnitude [absolute value], 27.9D 11.6D); vertical deviations, from 8D to 25D (mean magnitude, 13.1D 4.9D). Preoperatively, 18 patients (78%) presented with diplopia. Of the 5 patients without diplopia, 4 had sensory exotropia (best-corrected visual acuity of #20/400) and 1 had a long-standing large-angle exotropia, which likely enabled the patient not to experience diplopia. A retina specialist confirmed that the retina was attached prior to strabismus surgery. Twenty-one patients (91%) underwent surgery in the same eye as the scleral buckle; 2 underwent surgery in the contralateral eye with lower best-corrected visual acuity. Eighteen patients (78%) underwent strabismus surgery using an adjustable suture technique, of whom 5 patients required postoperative adjustment consisting of re-recessions of 1–3 mm (mean, 2 mm). In these patients, although the position of the buckle was considered during postoperative adjustment, there is a chance that in some cases the muscle may have healed onto the silicone band. Two patients (9%) underwent a second operation. The mean postoperative followup was 9.2 11.9 months (range, 2-36 months). Alignment Outcomes Surgical success was achieved in 16 patients (70%) after the first surgery and in 17 (74%) after two surgeries. Motor
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Volume - Number - / - 2018 surgical success was achieved in 15 of 21 patients (71%) with surgery on the eye with the scleral buckle and in both patients with surgery on the contralateral eye. The patient’s age (P 5 0.35), number of RD surgeries (P 5 0.73), time to strabismus surgery (P 5 0.70), bestcorrected visual acuity in the worse eye (P 5 0.73), macular status (P 5 0.15), or magnitude of preoperative horizontal (P 5 0.19) or vertical deviation (P 5 0.32) addressed surgically were not statistically significantly different in those with and without a successful motor outcome. Sensory Outcomes Of the 18 patients with diplopia and preoperative fusional capability, 17 (94%) reported subjective improvement of diplopia after surgery in primary position at distance and near. Of these, 6 experienced complete resolution of diplopia. Of the 12 patients (67%) with some degree of postoperative diplopia, 4 could fuse intermittently, 7 fused with a Fresnel or ground-in prism, and 1 continued to have constant diplopia. In these cases of complex strabismus, the authors considered postoperative sensory success to be intermittent fusion in primary gaze, although some patients may have had residual diplopia in eccentric positions of gaze. In 14 of these 18 patients (78%) with preoperative fusional capability, postoperative motor outcome was successful. Five of these 14 patients (36%) had complete resolution of diplopia and 9 (64%) continued to experience some postoperative diplopia, including the patient with constant postoperative diplopia. The patient’s age (P 5 1.00), number of RD surgeries (P 5 0.46), time to strabismus surgery (P 5 0.74), best-corrected visual acuity in the worse eye (P 5 0.31), macular status (P 5 0.36), and magnitude of preoperative horizontal (P 5 0.23) and vertical deviation (P 5 0.52) were not statistically significantly different for those who did and did not have some degree of postoperative diplopia after a successful motor outcome.
Discussion The reported success rates of strabismus surgeries after scleral buckle surgery are lower than those of noncomplex strabismus surgeries. In our study cohort 74% of patients with strabismus after scleral buckle procedure achieved successful alignment after strabismus surgery without scleral buckle removal. These results agree with those of several previous studies showing success rates ranging from 47% to 80%.2,5,6,9-11 However, our results are based on a short follow-up time, because many patients continued care with their primary retina or general ophthalmologist after 2 months. The variable success rates are likely attributed to the wide range of causes of strabismus after scleral buckle surgery, including direct muscle injury, myotoxicity from peribulbar/retrobulbar anesthetic injection, scleral dissection, interference with muscle function by the scleral buckle, scarring of Tenon’s capsule, and orbital fat adhesions.1,12-15 Disturbance in fusional ability
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may also induce strabismus. Fusion may be lost because of poor visual acuity following RD or anisometropia from the myopic shift caused by axial elongation by the scleral buckle.5,16-18 In some cases the mechanism is multifactorial, which may explain the high rate of combined horizontal and vertical strabismus reported in this case series (65%) as well as in other studies.2,10,16,18-20 Because the standard strabismus surgical dose tables may not be as reliable for these complex cases, adjustable sutures may be beneficial. Adjustable sutures were used in 18 patients (78%), 5 of whom required postoperative adjustment. Success at last follow-up was achieved in 72% of the adjusted patients. The timing of strabismus onset varies. Previous studies have shown that some patients develop strabismus and diplopia in the immediate postoperative period, whereas others develop it months or even years after the RD surgery.2,10 In our series, the onset of strabismus ranged from 1 month to 3.5 years. It is possible that the time of onset of strabismus may depend on the responsible mechanism. A myotoxic effect or direct damage to the muscle may cause strabismus immediately after scleral buckle surgery, whereas mechanical factors may occur weeks or months after surgery as scarring develops.16,20 A sensory deviation can also develop months after vision is lost. In patients with strabismus, diplopia may be influenced by both the degree of deviation and by visual acuity. Because most of our patients had a visual acuity of .20/ 400, 78% reported diplopia preoperatively. This is consistent with rates of postoperative diplopia reported by Spencer and colleagues (72%)21 and Rabinowitz and colleagues (100%).2 It has been reported that some patients may continue to experience diplopia postoperatively even after a successful postoperative motor outcome is achieved. Rabinowitz and colleagues reported that 8 of their patients (38%) experienced residual diplopia, of whom 4 had motor success at final follow-up.2 In our study, diplopia persisted in 9 patients despite a successful motor outcome. Because these were usually low-magnitude angles of deviation (\10D, eTable 1), all patients except one were able to fuse intermittently or with prismatic correction. Scleral buckle removal without strabismus surgery has been attempted as a means to alleviate diplopia, but diplopia persisted in the majority of patients (80%100%).4,7,19,22 Although Chang and colleagues6 reported a 62.5% success rate with scleral buckle removal during strabismus surgery compared to 10% without scleral buckle removal,6 Rabinowitz and colleagues2 found no difference. Other studies suggest that the removal of the scleral buckle would not necessarily have a positive effect on the strabismus outcome and therefore should be only considered if the scleral buckle itself seems to be related to the deviation.4,9,19 In our practice, we usually do not remove the scleral buckle. Because our motor success rates (70% for the first surgery and 74% for the second
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surgery) are on the higher end of reported results, we believe that scleral buckle removal is not necessary to achieve a good postoperative outcome. In addition, studies have shown that scleral buckle removal might expose patients to a risk of redetachment, which has been reported to range from 4% to 33%.7,8 Approximately 50% of our patients presenting with strabismus after RD repair have already required multiple previous RD surgeries because of redetachments. Therefore, we prefer to leave the scleral buckle intact and only remove in select cases with prior approval of the retina surgeon. This study has several limitations including the relatively small number of patients, its retrospective nature, and the lack of complete data for all patients. In addition, data regarding the scleral buckle type, size, and orientation was not available. Nevertheless, our results indicate that motor success and symptomatic improvement of diplopia may be achieved without scleral buckle removal.
Acknowledgments The authors acknowledge the contribution of Craig A. McKeown, MD, Bascom Palmer Eye Institute, in the form of patient recruitment and discussion of scientific content. References 1. Wolff SM. Strabismus after retinal detachment surgery. Trans Am Ophthalmol Soc 1983;81:182-92. 2. Rabinowitz R, Velez FG, Pineles SL. Risk factors influencing the outcome of strabismus surgery following retinal detachment surgery with scleral buckle. J AAPOS 2013;17:594-7. 3. Kasbekar SA, Wong V, Young J, Stappler T, Durnian JM. Strabismus following retinal detachment repair: a comparison between scleral buckling and vitrectomy procedures. Eye (Lond) 2011;25:1202-6. 4. Fison PN, Chignell AH. Diplopia after retinal detachment surgery. Br J Ophthalmol 1987;71:521-5. 5. Chaudhry NL, Durnian JM. Post-vitreoretinal surgery strabismus-a review. Strabismus 2012;20:26-30.
6. Chang JH, Hutchinson AK, Zhang M, Lambert SR. Strabismus surgery outcomes after scleral buckling procedures for retinal reattachment. Strabismus 2013;21:235-41. 7. Schwartz PL, Pruett RC. Factors influencing retinal redetachment after removal of buckling elements. Arch Ophthalmol 1977;95:804-7. 8. Moisseiev E, Fogel M, Fabian ID, Barak A, Moisseiev J, Alhalel A. Outcomes of scleral buckle removal: experience from the last decade. Curr Eye Res 2017;42:766-70. 9. Mu~ noz M, Rosenbaum AL. Long-term strabismus complications following retinal detachment surgery. J Pediatr Ophthalmol Strabismus 1987;24:309-14. 10. Ganekal S, Nagarajappa A. Strabismus following scleral buckling surgery. Strabismus 2016;24:16-20. 11. Seaber JH, Buckley EG. Strabismus after retinal detachment surgery: etiology, diagnosis, and treatment. Semin Ophthalmol 1995;10:61-73. 12. Arruga A. Motility disturbances induced by operations for retinal detachment. Mod Probl Ophthalmol 1977;18:408-14. 13. Wright KW. The fat adherence syndrome and strabismus after retina surgery. Ophthalmology 1986;93:411-15. 14. Cooper LL, Harrison S, Rosenbaum AL. Ocular torsion as a complication of scleral buckle procedures for retinal detachments. J AAPOS 1998;2:279-84. 15. Salama H, Farr AK, Guyton DL. Anesthetic myotoxicity as a cause of restrictive strabismus after scleral buckling surgery. Retina 2000;20: 478-82. 16. Smiddy WE, Loupe D, Michels RG, Enger C, Glaser BM, de Bustros S. Extraocular muscle imbalance after scleral buckling surgery. Ophthalmology 1989;96:1485-9. 17. Kutschera E, Antlanger H. Influence of retinal detachment surgery on eye motility and binocularity. Mod Probl Ophthalmol 1979;20:354-8. 18. Maurino V, Kwan A, Khoo BK, Gair E, Lee JP. Ocular motility disturbances after surgery for retinal detachment. J AAPOS 1998;2: 285-92. 19. Wong V, Kasbekar S, Young J, Stappler T, Marsh IB, Durnian JM. The effect of scleral exoplant removal on strabismus following retinal detachment repair. J AAPOS 2011;15:331-3. 20. Farr AK, Guyton DL. Strabismus after retinal detachment surgery. Curr Opin Ophthalmol 2000;11:207-10. 21. Spencer AF, Newton C, Vernon SA. Incidence of ocular motility problems following scleral buckling surgery. Eye (Lond) 1993;7:751-6. 22. Deokule S, Reginald A, Callear A. Scleral explant removal: the last decade. Eye (Lond) 2003;17:697-700.
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4.e1
Success
Followup, mos
eTable 1. Pre- and postoperative patient characteristics Deviation, PD BCVA in operated Patient eye
Pre-op Surgery
Adjusted
2 3
L-LR rec 8 mm adj No L-MR res 6 mm SP 2 mm NLP L-LR rec 12 mm N/A 20/200 L-IR rec 5 mm adj No
4
20/25
1
5 6
7 8 9 10 11 12
13 14 15 16 17 18 19 20 21
22 23
20/60
L-LR rec 8 mm adj L-SR rec 7 mm adj 20/60 R-LR rec 8 mm adj R-MR res 6.5 mm 20/50 #1 R-SR rec 4 mm adj R-IR res 3 mm #2 R-IO myectomy 5 mm R-IR res 4 mm adj 20/60 L-LR rec 5.5 mm 20/40 L-LR rec 8 mm adj L-MR res 5 mm IP 2 mm 20/150 R-MR rec 7 mm 20/350 L-MR rec 7 mm adj
H
Post-op V
H
V
Pre-op
Post-op
Motor
Sensory
45 L-XTa 8 L-HoTa
6 L-XT
5 L-HoT Yes
No
No
Yes
2
35 L-XTa
15 L-XT
No 12 L-HoT Yes
No Yes: Fresnel prism Yes: Fresnel prism No
No No
N/A Nob
2 12
No
Nob
2
No
N/A
3
14 L-HoTa
No
18 L-XTa 16 L-HTa
Re-rec 2 mm No
60 R-XTa 10 R-HoT 25 R-XT 6 R-HoT No
N/A No
25 L-XTa 4 L-HT 25 L-XTa 8 L-HTa
8 L-XT 4 XT
N/A No
25 R-ETa 4 R-HT 30 L-ETa
4 R-E(T) 6 L-E(T)
20 L-XT 18 L-HT Yes
25 R-HTa
20/250 L-IR rec 4.5 mm adj Re-rec 6 L-XT 1 mm 20/60 L-SR rec 3 mm adj L-SR re-rec 10 L-XTa L-LR rec 5 mm adj 3 mm L-LR Re-rec 3 mm CF 3 ft LLR rec 10 mm N/A 20 L-XTa 20/40 RLR rec adj No 30 R-XTa RMR adv 20/70 LMR rec 3.5 mm adj L-MR re-rec 16 L-ETa LIR rec 4.5 mm adj 1 mm 20/40c LIR rec 5.5 mm adj L-IR re-rec 2 20 R-XTa LLR rec 9 mm adj LP RLR rec 8 mm N/A 30 R-XTa RMR res 6 mm 16 L-XTa 20/30c RLR rec 10 mm adj No 20/20 RSR rec adj 20/100 RMR rec 6 mm adj RLR res 4 mm and adv 4 mm 20/250 #1 LMR rec 2 mm adj LLR adv 4 mm #2 LMR rec 4 mm adj 20/80 RLR rec 5.5 mm adj RMR res 4.5 mm 20/400 RLR rec 11 mm adj SP 3 mm
Diplopia
14 L-HoTa 4 L-XT
7 R-HT
Yes
Yes: ground-in No prism
Nob
36
4 L-HT
Yes Yes
Intermittent Intermittent
Yes Yes
Nob Nob
2 2
Yes Yes
No Yes Yes: ground-in Yes prism Yes Yes
Yes Nob
10 9
3 L-HoT Yes
No; constant diplopia Nob
2
12 L-HTa
8 L-X(T) 4 L-H(T) Yes
Yes: ground-in Yes prism
10 L-HT
Ortho Ortho
No Yes
No No
Yes Yes
N/A Yes
2 2
14 L-HoTa
2 L-HoT Yes
No
Yes
Yes
36
15 R-HTa 8 L-XT
4 R-HT
Yes
Yes
Nob
2
Ortho
No
Yes: Fresnel prism No
Yes
N/A
2
Ortho 3 L-HT
10 L-XT 2 R-HT
Yes
32
Yes
Nob
3
Yes Yes
Nob Yes
31 9
No No
10 R-X(T) 10 R-H(T)a 10 R-XT 40 R-ETa 2 R-E(T)
Yes Yes
Yes: Fresnel prism Intermittent No
No
30 L-ETa
Ortho
Yes
No
Yes
Yes
6
No
30 R-XTa 5 R-HT
4 R-X(T) 3 R-H(T) Yes
Intermittent
Yes
Nob
2
No
25 R-XTa 8 R-HoTa 6 R-XT 2 R-HoT No
No
Yes
N/A
2
Adj, adjustable; Adv, advancement; BCVA, best-corrected visual acuity; ET, esotropia; H, horizontal; HoT, hypotropia; HT, hypertropia; H(T), intermittent hypertropia; IO, inferior oblique muscle; IP, infraplacement; L, left; IR, inferior rectus muscle; LR, lateral rectus muscle; MR, medial rectus muscle; N/A, not applicable; PD, prism diopter; R, right; Rec, recession; Re-rec, re-recession; Res, resection; RET, right esotropia; SP, supraplacement; SR, superior rectus muscle; V, vertical; XT, exotropia; X(T), intermittent exotropia. a Deviation addressed in surgical procedure. b No motor success but subjective improvement. c Patients in whom strabismus surgery was performed on the eye without scleral buckle.
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