- Email: [email protected]
Efficacy of the intraoperative relaxed muscle positioning technique in thyroid eye disease and analysis of cases requiring reoperation
Efficacy of the intraoperative relaxed muscle positioning technique in thyroid eye disease and analysis of cases requiring reoperation Benjamin P. Nicholson, MD, Manuel De Alba, MD, Julian D. Perry, MD, and Elias I. Traboulsi, MD PURPOSE
METHODS
In the relaxed muscle positioning technique of treating strabismus for thyroid eye disease (TED), the most restricted muscles, as determined by preoperative assessment of ductions and intraoperative forced ductions, are recessed to the positions where they rest freely on the globe without tension. The purpose of this technique is to identify preoperative characteristics that are predictive of reoperation and evaluate outcomes. Retrospective review of patients with TED who underwent strabismus surgery using the relaxed muscle positioning technique between 1999 and 2009. Preoperative characteristics; surgical outcomes at 2, 6, and 12 months; and the outcomes of reoperations were evaluated. Outcomes were categorized as excellent (no diplopia in primary and reading gazes without prisms), good (diplopia requiring #10D correction), and poor (persistent diplopia in primary or reading gazes despite prism or attempted prism correction).
RESULTS
Of 63 TED patients treated during the study period, 58 met inclusion criteria. Of these, 45 patients (78%) underwent only one strabismus surgery; 10 (17%), 2 surgeries; and 3 (5%), 3. Excellent outcomes were achieved in 48 (83%), good in 4 (7%), and poor in 6 (10%). Mean follow-up was 12.1 months (range, 1.5 months to 11.5 years). There was an increased likelihood for reoperation in patients with multiple treatment modalities for Graves disease (P 5 0.03) and larger horizontal deviations (P 5 0.03).
CONCLUSIONS
The intraoperative relaxed muscle positioning technique improved ocular alignment and relieved diplopia in most patients with dysthyroid strabismus. Patients with more severe disease were more likely to require reoperation. ( J AAPOS 2011;15:321-325)
T
hyroid eye disease (TED) is characterized by inflammation and fibrosis of the extraocular muscles and other orbital tissues, sometimes resulting in strabismus and diplopia. Strabismus surgery is required in 4%-7% of patients diagnosed with TED.1,2 Success rates of strabismus surgery in TED patients vary between 38%3 and 80%4 with fixed suture techniques and between 64%3 and 82%5 with adjustable sutures. In several series during the last decade, authors have investigated duction-based surgery for strabismus in TED.6-8 This technique involves performing preoperative duction assessment and intraoperative forced duction testing and recessing restricted muscles rather than devising a treatment strategy based primarily on the angle of strabismus. Nguyen and colleagues7 reported a 74% success rate with this approach, whereas Thomas and Cruz8 reAuthor affiliations: Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio Submitted August 21, 2010. Revision accepted March 8, 2011. Published online July 21, 2011. Reprint requests: Elias I. Traboulsi, MD, Cole Eye Institute, Cleveland Clinic Department of Pediatric Ophthalmology and Center for Genetic Eye Diseases, 9500 Euclid Avenue, Cleveland, OH, 44195 (email: [email protected]). Copyright Ó 2011 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 doi:10.1016/j.jaapos.2011.03.014
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ported a 66% success rate. Our technique, first described in 2006 by Dal Canto and colleagues,6 differs somewhat from that of Nguyen and colleagues7 and Thomas and Cruz8 (discussed in detail in this paper). Given the large percentage of patients who require more than one strabismus surgery for TED-related strabismus, the ability to predict which patients will need more than one surgery would allow for better preoperative counseling and might help clinicians improve management strategies. Such analysis has not been reported to date in other studies of duction-based surgery and has been limited in studies of other techniques. In the current study, we analyze the preoperative characteristics of patients who required reoperation, describe the clinical scenarios that in our experience tend to predict reoperation, and evaluate the efficacy of our intraoperative relaxed muscle positioning technique.
Subjects and Methods Patients Cleveland Clinic Institutional Review Board approval was obtained for the chart review of consecutive patients with TED-associated strabismus who underwent strabismus surgery with the intraoperative relaxed muscle positioning technique between 1999 and 2009 by one surgeon (EIT). All data were secured
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in compliance with the Health Insurance Portability and Accountability Act. Surgery was performed only after patients had been in the postinflammatory stage for at least 6 months. No patient underwent orbital decompression in the 3 months preceding strabismus surgery. All patients included in the study had at least 1.5 months of follow-up. Patients with no preoperative diplopia or no light perception vision at any point during the study period were excluded. Charts were reviewed for sex, age at diagnosis, previous systemic treatments for Graves disease, visual acuity, intraocular pressure, manifest refraction, exophthalmometry, type of restriction after forced duction testing, clinical deviation in primary position, presence of diplopia, relation of diplopia to orbital decompression, length of clinical stability before corrective muscle surgery, surgical procedure performed, extent of muscle recessions, follow-ups after strabismus correction (2 months, 6 months, and 1 year), final results (defined as condition at last follow-up visit), additional surgical procedures, and date of last follow-up examination. We assessed for surgical complications, including globe perforation, postoperative bleeding or infection, wound dehiscence, and slipped muscles.
Outcome Analysis An excellent outcome was defined as one with no diplopia in primary and reading gazes without prisms. A good outcome was defined as no diplopia in primary and reading positions with the use of a #10D correction. A poor outcome was defined as persistent diplopia in primary or reading gazes despite moderate prism or the inability of the patient to tolerate the necessary prisms. Linear regression was used to determine whether a correlation existed between the degree of strabismus and amount of recession required to eliminate diplopia. These data were compared with a plot of suggested surgical doses from a published nomogram. Preoperative characteristics were analyzed for factors predictive of a need for more than one strabismus surgery. These analyses were performed with the Fisher exact test, c2 testing, or an unpaired t test. A P value of \0.05 was defined as significant.
Surgical Technique The surgical technique has been described in detail previously.6 We would like to reemphasize the importance of preoperative duction testing. Here we reiterate the key points of the surgical technique: once the patient was under general anesthesia, forced duction testing was performed to confirm which muscles were restricted; a fornix incision was created to expose the insertion of the muscle of interest; intermuscular attachments and check ligaments were severed with scissors; and care was taken to lyse the capsulopalpebral ligaments during inferior rectus recession. After the muscle was disinserted from the globe, forced ductions were repeated to ensure free movement of the globe. The disinserted muscle was then allowed to rest freely on the globe without tension with the anteroposterior axis of the eye perpendicular to the frontal plane. The position at which the disinserted tendon rested against the sclera was then marked. The distance from the original insertion to this mark was measured with a flexible ruler and recorded. The tendon was then
Volume 15 Number 4 / August 2011 sutured to the sclera at the site of the mark in standard fashion. No more than 2 ipsilateral rectus muscles were recessed during any one procedure.
Results A total of 63 TED patients underwent intraoperative relaxed muscle positioning technique strabismus surgery during the study period. Of these, 58 (40 females [69%]) met inclusion criteria. Follow-up ranged from 1.5 months to 11.5 years, with a mean follow-up of 12.1 months (Table 1). Patient age ranged from 21 to 77 years (mean, 51.5 years). Bilateral inferior rectus muscle recession combined with bilateral medial rectus muscle recession was the most commonly performed surgery (15 of 58; 26%). Other surgeries performed more than once are detailed in Table 2. There were no surgical complications. Thirty-seven of the 58 patients (64%) had undergone previous orbital decompression 3 or more months before strabismus surgery. Of the 37, 21 (57%) had diplopia before decompression and 16 developed diplopia only after decompression (43%). A mean of 2.4 muscles per patient were recessed in the first surgery. A mean of 2.5 muscles per patient were recessed in those who had undergone previous orbital decompression, while 2.1 per patient were recessed in those who had not undergone decompression (P 5 0.14). Forty-five patients (78%) underwent only one strabismus surgery; 10 (17%), 2 surgeries; 3 (5%), 3. On average there were 1.3 surgeries per patient. Of the 13 patients who required more than one surgery, 11 (85%) had good or excellent final outcomes. A second surgery had been planned as part of a staged strabismus repair for 1 of these 13. Regression analysis failed to reveal a strong relationship between the amount of recession performed and the clinical angle of strabismus in any subgroup. R2 for patients with horizontal deviations and good or excellent outcomes with one surgery (Group 1) was 0.539, whereas for those requiring multiple surgeries or with poor outcomes it was 0.415 (Group 2; Figure 1).9 For vertical deviations, R2 for Group 1 was 0.723 and 0.121 for Group 2 (Figure 2). Of those patients in Group 2 for the vertical deviation analysis, 4 of 11 were in Group 2 for reasons other than persistent vertical diplopia. Numerous preoperative variables were analyzed for an association with the need for reoperation (Table 3). Four variables achieved a statistically significant association. More treatment modalities for Graves disease (for example, surgery and medication rather than just medication) was associated with reoperation (P 5 0.03). Larger horizontal deviations were associated with reoperation with a mean 22.4D (18.5-26.3, 95% confidence interval [95% CI]) deviation in the one surgery group and a 32.8D (22.4-43.2, 95% CI) mean deviation in the multiple surgeries group (P 5 0.03). This association also achieved statistical significance when patients with primarily horizontal (horizontal angle greater than vertical angle) strabismus were considered
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Table 1. Preoperative demographics of study patients
20
Follow-up Mean Range
18
Age, yr Mean Range Sex, n (%) Female Male Decompression before strabismus surgery Diplopia, no history of decompression Diplopia prior to decompression Diplopia only after decompression Mean number of muscles operated
51.5 21–77 40 (69) 18 (31) 37/58 21/58 21/58 16/58 2.4
Group 1 (R² = 0.5389) Group 2 (R² = 0.4149)
16
Amount of recession (mm)
12.1 months 1.5 months to 11.5 years
323
Nomogram (R² = 0.883)
14 12 10 8 6 4 2 0 0
10
Table 2. Surgeries performed Surgery performed
Frequency, n (%)
Bilateral IR recession and bilateral MR recession Unilateral MR and IR recession Bilateral MR recession Unilateral IR recession Unilateral MR recession Bilateral IR recession with unilateral MR recession Bilateral IR recession Unilateral lateral and IR recession Other surgeries performed once
13/58 (22) 9/58 (16) 9/58 (16) 6/58 (10) 4/58 (7) 3/58 (5) 3/58 (5) 2/58 (3) 9/58 (16)
IR, inferior rectus muscle; MR, medial rectus muscle.
separately (P 5 0.04, means 26.6 and 37.2, 22.0-31.2, and 26.9-47.5, 95% CIs). When compared with patients with primarily vertical strabismus, those with primarily horizontal deviations were more likely to require reoperation (P 5 0.04). Finally, patients who had diplopia before orbital decompression surgery were more likely to require multiple strabismus surgeries than those who developed diplopia after decompression (P 5 0.05). We furthermore attempted to ascertain the circumstances that led to reoperation in 13 patients. One patient, as noted previously, underwent a planned staged strabismus repair. Two patients had small vertical deviations that were unmasked after surgery for large-angle horizontal strabismus. One patient had a tight superior rectus muscle in an eye that underwent medial and inferior rectus muscle recession; the magnitude of this restriction was not appreciated until after the other muscles had been recessed. Similarly, another patient had 3 severely tight muscles in one orbit noted on initial examination, but only 2 were recessed in the first surgery. A second surgery addressed the third muscle. One patient had a hypertropia treated with bilateral inferior rectus recession; the hypertropia persisted nearly unchanged after the first surgery with severe limitation of downgaze in that eye. Another patient had an esotropia and one tight inferior rectus. We recessed one medial and one inferior rectus, and the
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20 30 40 50 Preoperative deviation (prism diopters)
60
70
FIG 1. Horizontal muscles: millimeters of recession (total for all horizontal muscles recessed) versus preoperative deviation. Amount of recession performed in millimeters versus the measured preoperative angle of horizontal strabismus in prism diopters. Group 1 includes all patients with horizontal strabismus who had excellent or good outcomes after just one surgery. Group 2 includes patients who required more than one surgery or had a poor final outcome. Nomogram data includes data for esotropia and exotropia surgeries and is therefore not completely linear.9
patient developed vertical diplopia. Five patients were initially undercorrected; of those 5 undercorrected patients, 2 had more millimeters of recession when our method was used than what would have been prescribed by traditional nomograms, and 3 had less millimeters of recession. After one surgery, 41 of 58 patients (71%) had good or excellent outcomes. The final outcome was good or excellent in 52 (90%). Only one patient developed diplopia after having been diplopia-free at 2 month’s follow-up. Final outcomes were as follows: of the 58 patients, 48 (83%) had an excellent outcome, 4 (7%) had a good outcome, and 6 (10%) had a poor outcome. Of those with poor final outcomes, one had diplopia only in reading position and 2 had no diplopia with prism glasses (.10D).
Discussion Here we present results that are comparable with those of other series, and these results support the concept that the intraoperative relaxed muscle positioning technique is a good approach for TED patients. Some series have reported good results using surgical nomograms published for pediatric strabismus patients, but results from other series are mixed. Nomograms created for pediatric strabismus seem intuitively ill-suited to the TED population. Furthermore, the nomogram-based approach is particularly unhelpful when treating vertical deviations caused by bilateral inferior rectus restriction.
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16
Table 3. Analysis for factors predictive of the need for repeat surgery
Group 1 (R² = 0.723) 14
Group 2 (R² = 0.121)
Amount of recession (mm)
12
Analysis for factors predictive of the need for repeat surgery
Nomogram (R² = 1.00)
10 8 6 4 2 0 0
10
20
30
40
50
-2 -4 Preoperative deviation (prism diopters)
FIG 2. Vertical muscles: millimeters of recession (total for all vertical muscles recessed) versus preoperative deviation. Amount of recession performed in millimeters versus the measured preoperative angle of vertical strabismus in prism diopters. Group 1 includes all patients with vertical strabismus who had excellent or good outcomes after just one surgery. Group 2 includes patients who required more than one surgery or had a poor final outcome. Negative values reflect cases in which bilateral inferior rectus recession was performed with a larger recession in the unexpected eye.
Nguyen and colleagues7 and Thomas and Cruz8 have reported on techniques similar to ours with comparable results. Our technique differs from these in several respects. We fully relieve the restriction in each recessed muscle rather than trying to match the restriction in the contralateral eye. We operate through a fornix incision. Finally, we resuture the muscle to the globe with the eye in primary position rather than attempt to match the intraoperative eccentric position of the contralateral eye. Nguyen and colleagues had a 74% success rate (n 5 39) with one surgery. Their results are perhaps buoyed by their exclusion of patients who had repeat surgeries in the first 30 postoperative days and their lack of assessment for diplopia in reading position. Thomas and Cruz had a 66% success rate (n 5 47) in their duction correction group but also did not comment on diplopia in reading position.8 If we apply the same definition of success as these 2 studies, our success rate after one surgery was 74%. Reoperation rates for the three reports would be as follows: Nguyen and colleagues 27%, Thomas and Cruz 18%, and 21% for the present series. Our series reports a relatively long follow-up period, and this allows for analysis of ultimate outcomes. Ninety percent of our patients eventually had a successful outcome. Among those that required a second surgery, the rate of successful outcomes was also relatively high (85%). The need for a second surgery should therefore not be seen as a predictor of failure. We encountered 2 special circum-
Single vs multiple treatments for hyperthyroidism (multiple treatment modalities associated with $2 surgeries) Horizontal muscles vs vertical vs both Bilateral surgery vs unilateral Nature of treatment for hyperthyroidism $3 line asymmetry in visual acuity Presence of refractive error (those with no significant refractive error required more surgeries) Myopia vs hyperopia Prior orbital decompression Bilateral vs unilateral decompression Diplopia before decompression vs after Diplopia before decompression vs all others (diplopia before decompression associated with greater rate of second surgery) Vertical strabismus vs horizontal vs mixed Primarily horizontal strabismus versus primarily vertical (those with primarily horizontal strabismus were more likely to undergo reoperation) Monocular surgery vs binocular Angle of horizontal strabismus (all patients with horizontal strabismus included: those with larger angles more likely to undergo reoperation) Angle of vertical strabismus (all patients with vertical strabismus included) Age at diagnosis Number of muscles operated Hertel asymmetry Hertel change with decompression
P value 0.03a 0.15b 0.62a 0.14b 0.49a 0.09a 0.22b 0.12a 0.63a 0.27a 0.05b 0.12b 0.04a 0.53a 0.03c 0.64c 0.75c 0.29c 0.73c 0.63c
a
Fisher exact test. c test. c Unpaired t test. b 2
stances that led to reoperation more than once in this series. First, the treatment of a large-angle esotropia may unmask a smaller-angle vertical deviation and necessitate more surgery. Second, patients with three restricted muscles in one eye will require multiple surgeries to prevent anterior segment ischemia. Published success rates for deviation-based or nomogram-based strabismus repairs in TED patients vary between 38%3 and 82%,5 and reoperation rates range from 5% to 45%.3,10 Adjustable suture techniques in some series have provided a comparable success rate to ductionbased surgery,2,5 but the duction-based techniques obviate the need for postoperative manipulation. Factors that may have been predictive of the need for reoperation included: (1) multiple treatment modalities for Graves disease; (2) diplopia before orbital decompression; (3) primarily horizontal strabismus; and (4) larger angles of strabismus in the horizontal plane; however, each will require further investigation for confirmation. Perhaps more relevant were the numerous preoperative factors that did not correlate with a need for reoperation (Table 3). Our data set did not support the initial findings of Dal Canto and colleagues6 that patients who developed
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diplopia only after orbital decompression tended to require less surgery and have better outcomes. References 1. Lueder GT, Scott WE, Kutschke PJ, Keech RV. Long-term results of adjustable suture surgery for strabismus secondary to thyroid ophthalmopathy. Ophthalmology 1992;99:993-7. 2. Inoue Y, Tsuboi T, Kouzaki A, Maeda T, Inoue T. Ophthalmic surgery in dysthyroid ophthalmopathy. Thyroid 2002;12:257-63. 3. Kraus DJ, Bullock JD. Treatment of thyroid ocular myopathy with adjustable and nonadjustable suture strabismus surgery. Trans Am Ophthalmol Soc 1993;91:67-79. Discussion 79-84. 4. Evans D, Kennerdell JS. Extraocular muscle surgery for dysthyroid myopathy. Am J Ophthalmol 1983;95:767-71.
5. Flanders M, Hastings M. Diagnosis and surgical management of strabismus associated with thyroid-related orbitopathy. J Pediatr Ophthalmol Strabismus 1997;34:333-40. 6. Dal Canto AJ, Crowe S, Perry JD, Traboulsi EI. Intraoperative relaxed muscle positioning technique for strabismus repair in thyroid eye disease. Ophthalmology 2006;113:2324-30. 7. Nguyen VT, Park DJ, Levin L, Feldon SE. Correction of restricted extraocular muscle motility in surgical management of strabismus in graves’ ophthalmopathy. Ophthalmology 2002;109:384-8. 8. Thomas SM, Cruz OA. Comparison of two different surgical techniques for the treatment of strabismus in dysthyroid ophthalmopathy. J AAPOS 2007;11:258-61. 9. Wright KW, Ryan SJ. Color atlas of ophthalmic surgery. Philadelphia, PA: Lippincott; 1991. 10. Dyer JA. The oculorotary muscles in Graves’ disease. Trans Am Ophthalmol Soc 1976;74:425-56.
An Eye on the Arts—The Arts on the Eye “Even after her cornea transplant, Mammachi could only see light and shadow. If somebody was standing in the doorway, she could tell that someone was standing in the doorway. But not who it was. She could read a cheque, or a receipt, or a bank note only if it was close enough for her eyelashes to touch it. She would then hold it steady, and move her eye along it. Wheeling it from word to word. The Townspeople (in her fairy frock) saw Mammachi draw Sophie Mol close to her eyes to look at her. To read her like a cheque. To check her like a bank note. Mammachi (with her better eye) saw redbrown hair (N. Nalmost blond), the curve of two fatfreckled cheeks (Nnnn. almost rosy), bluegreyblue eyes.” — Arundhati Roy (from The God of Small Things, India Ink, New Delhi, India, 1997)
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METHODS
In the relaxed muscle positioning technique of treating strabismus for thyroid eye disease (TED), the most restricted muscles, as determined by preoperative assessment of ductions and intraoperative forced ductions, are recessed to the positions where they rest freely on the globe without tension. The purpose of this technique is to identify preoperative characteristics that are predictive of reoperation and evaluate outcomes. Retrospective review of patients with TED who underwent strabismus surgery using the relaxed muscle positioning technique between 1999 and 2009. Preoperative characteristics; surgical outcomes at 2, 6, and 12 months; and the outcomes of reoperations were evaluated. Outcomes were categorized as excellent (no diplopia in primary and reading gazes without prisms), good (diplopia requiring #10D correction), and poor (persistent diplopia in primary or reading gazes despite prism or attempted prism correction).
RESULTS
Of 63 TED patients treated during the study period, 58 met inclusion criteria. Of these, 45 patients (78%) underwent only one strabismus surgery; 10 (17%), 2 surgeries; and 3 (5%), 3. Excellent outcomes were achieved in 48 (83%), good in 4 (7%), and poor in 6 (10%). Mean follow-up was 12.1 months (range, 1.5 months to 11.5 years). There was an increased likelihood for reoperation in patients with multiple treatment modalities for Graves disease (P 5 0.03) and larger horizontal deviations (P 5 0.03).
CONCLUSIONS
The intraoperative relaxed muscle positioning technique improved ocular alignment and relieved diplopia in most patients with dysthyroid strabismus. Patients with more severe disease were more likely to require reoperation. ( J AAPOS 2011;15:321-325)
T
hyroid eye disease (TED) is characterized by inflammation and fibrosis of the extraocular muscles and other orbital tissues, sometimes resulting in strabismus and diplopia. Strabismus surgery is required in 4%-7% of patients diagnosed with TED.1,2 Success rates of strabismus surgery in TED patients vary between 38%3 and 80%4 with fixed suture techniques and between 64%3 and 82%5 with adjustable sutures. In several series during the last decade, authors have investigated duction-based surgery for strabismus in TED.6-8 This technique involves performing preoperative duction assessment and intraoperative forced duction testing and recessing restricted muscles rather than devising a treatment strategy based primarily on the angle of strabismus. Nguyen and colleagues7 reported a 74% success rate with this approach, whereas Thomas and Cruz8 reAuthor affiliations: Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio Submitted August 21, 2010. Revision accepted March 8, 2011. Published online July 21, 2011. Reprint requests: Elias I. Traboulsi, MD, Cole Eye Institute, Cleveland Clinic Department of Pediatric Ophthalmology and Center for Genetic Eye Diseases, 9500 Euclid Avenue, Cleveland, OH, 44195 (email: [email protected]). Copyright Ó 2011 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 doi:10.1016/j.jaapos.2011.03.014
Journal of AAPOS
ported a 66% success rate. Our technique, first described in 2006 by Dal Canto and colleagues,6 differs somewhat from that of Nguyen and colleagues7 and Thomas and Cruz8 (discussed in detail in this paper). Given the large percentage of patients who require more than one strabismus surgery for TED-related strabismus, the ability to predict which patients will need more than one surgery would allow for better preoperative counseling and might help clinicians improve management strategies. Such analysis has not been reported to date in other studies of duction-based surgery and has been limited in studies of other techniques. In the current study, we analyze the preoperative characteristics of patients who required reoperation, describe the clinical scenarios that in our experience tend to predict reoperation, and evaluate the efficacy of our intraoperative relaxed muscle positioning technique.
Subjects and Methods Patients Cleveland Clinic Institutional Review Board approval was obtained for the chart review of consecutive patients with TED-associated strabismus who underwent strabismus surgery with the intraoperative relaxed muscle positioning technique between 1999 and 2009 by one surgeon (EIT). All data were secured
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in compliance with the Health Insurance Portability and Accountability Act. Surgery was performed only after patients had been in the postinflammatory stage for at least 6 months. No patient underwent orbital decompression in the 3 months preceding strabismus surgery. All patients included in the study had at least 1.5 months of follow-up. Patients with no preoperative diplopia or no light perception vision at any point during the study period were excluded. Charts were reviewed for sex, age at diagnosis, previous systemic treatments for Graves disease, visual acuity, intraocular pressure, manifest refraction, exophthalmometry, type of restriction after forced duction testing, clinical deviation in primary position, presence of diplopia, relation of diplopia to orbital decompression, length of clinical stability before corrective muscle surgery, surgical procedure performed, extent of muscle recessions, follow-ups after strabismus correction (2 months, 6 months, and 1 year), final results (defined as condition at last follow-up visit), additional surgical procedures, and date of last follow-up examination. We assessed for surgical complications, including globe perforation, postoperative bleeding or infection, wound dehiscence, and slipped muscles.
Outcome Analysis An excellent outcome was defined as one with no diplopia in primary and reading gazes without prisms. A good outcome was defined as no diplopia in primary and reading positions with the use of a #10D correction. A poor outcome was defined as persistent diplopia in primary or reading gazes despite moderate prism or the inability of the patient to tolerate the necessary prisms. Linear regression was used to determine whether a correlation existed between the degree of strabismus and amount of recession required to eliminate diplopia. These data were compared with a plot of suggested surgical doses from a published nomogram. Preoperative characteristics were analyzed for factors predictive of a need for more than one strabismus surgery. These analyses were performed with the Fisher exact test, c2 testing, or an unpaired t test. A P value of \0.05 was defined as significant.
Surgical Technique The surgical technique has been described in detail previously.6 We would like to reemphasize the importance of preoperative duction testing. Here we reiterate the key points of the surgical technique: once the patient was under general anesthesia, forced duction testing was performed to confirm which muscles were restricted; a fornix incision was created to expose the insertion of the muscle of interest; intermuscular attachments and check ligaments were severed with scissors; and care was taken to lyse the capsulopalpebral ligaments during inferior rectus recession. After the muscle was disinserted from the globe, forced ductions were repeated to ensure free movement of the globe. The disinserted muscle was then allowed to rest freely on the globe without tension with the anteroposterior axis of the eye perpendicular to the frontal plane. The position at which the disinserted tendon rested against the sclera was then marked. The distance from the original insertion to this mark was measured with a flexible ruler and recorded. The tendon was then
Volume 15 Number 4 / August 2011 sutured to the sclera at the site of the mark in standard fashion. No more than 2 ipsilateral rectus muscles were recessed during any one procedure.
Results A total of 63 TED patients underwent intraoperative relaxed muscle positioning technique strabismus surgery during the study period. Of these, 58 (40 females [69%]) met inclusion criteria. Follow-up ranged from 1.5 months to 11.5 years, with a mean follow-up of 12.1 months (Table 1). Patient age ranged from 21 to 77 years (mean, 51.5 years). Bilateral inferior rectus muscle recession combined with bilateral medial rectus muscle recession was the most commonly performed surgery (15 of 58; 26%). Other surgeries performed more than once are detailed in Table 2. There were no surgical complications. Thirty-seven of the 58 patients (64%) had undergone previous orbital decompression 3 or more months before strabismus surgery. Of the 37, 21 (57%) had diplopia before decompression and 16 developed diplopia only after decompression (43%). A mean of 2.4 muscles per patient were recessed in the first surgery. A mean of 2.5 muscles per patient were recessed in those who had undergone previous orbital decompression, while 2.1 per patient were recessed in those who had not undergone decompression (P 5 0.14). Forty-five patients (78%) underwent only one strabismus surgery; 10 (17%), 2 surgeries; 3 (5%), 3. On average there were 1.3 surgeries per patient. Of the 13 patients who required more than one surgery, 11 (85%) had good or excellent final outcomes. A second surgery had been planned as part of a staged strabismus repair for 1 of these 13. Regression analysis failed to reveal a strong relationship between the amount of recession performed and the clinical angle of strabismus in any subgroup. R2 for patients with horizontal deviations and good or excellent outcomes with one surgery (Group 1) was 0.539, whereas for those requiring multiple surgeries or with poor outcomes it was 0.415 (Group 2; Figure 1).9 For vertical deviations, R2 for Group 1 was 0.723 and 0.121 for Group 2 (Figure 2). Of those patients in Group 2 for the vertical deviation analysis, 4 of 11 were in Group 2 for reasons other than persistent vertical diplopia. Numerous preoperative variables were analyzed for an association with the need for reoperation (Table 3). Four variables achieved a statistically significant association. More treatment modalities for Graves disease (for example, surgery and medication rather than just medication) was associated with reoperation (P 5 0.03). Larger horizontal deviations were associated with reoperation with a mean 22.4D (18.5-26.3, 95% confidence interval [95% CI]) deviation in the one surgery group and a 32.8D (22.4-43.2, 95% CI) mean deviation in the multiple surgeries group (P 5 0.03). This association also achieved statistical significance when patients with primarily horizontal (horizontal angle greater than vertical angle) strabismus were considered
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Table 1. Preoperative demographics of study patients
20
Follow-up Mean Range
18
Age, yr Mean Range Sex, n (%) Female Male Decompression before strabismus surgery Diplopia, no history of decompression Diplopia prior to decompression Diplopia only after decompression Mean number of muscles operated
51.5 21–77 40 (69) 18 (31) 37/58 21/58 21/58 16/58 2.4
Group 1 (R² = 0.5389) Group 2 (R² = 0.4149)
16
Amount of recession (mm)
12.1 months 1.5 months to 11.5 years
323
Nomogram (R² = 0.883)
14 12 10 8 6 4 2 0 0
10
Table 2. Surgeries performed Surgery performed
Frequency, n (%)
Bilateral IR recession and bilateral MR recession Unilateral MR and IR recession Bilateral MR recession Unilateral IR recession Unilateral MR recession Bilateral IR recession with unilateral MR recession Bilateral IR recession Unilateral lateral and IR recession Other surgeries performed once
13/58 (22) 9/58 (16) 9/58 (16) 6/58 (10) 4/58 (7) 3/58 (5) 3/58 (5) 2/58 (3) 9/58 (16)
IR, inferior rectus muscle; MR, medial rectus muscle.
separately (P 5 0.04, means 26.6 and 37.2, 22.0-31.2, and 26.9-47.5, 95% CIs). When compared with patients with primarily vertical strabismus, those with primarily horizontal deviations were more likely to require reoperation (P 5 0.04). Finally, patients who had diplopia before orbital decompression surgery were more likely to require multiple strabismus surgeries than those who developed diplopia after decompression (P 5 0.05). We furthermore attempted to ascertain the circumstances that led to reoperation in 13 patients. One patient, as noted previously, underwent a planned staged strabismus repair. Two patients had small vertical deviations that were unmasked after surgery for large-angle horizontal strabismus. One patient had a tight superior rectus muscle in an eye that underwent medial and inferior rectus muscle recession; the magnitude of this restriction was not appreciated until after the other muscles had been recessed. Similarly, another patient had 3 severely tight muscles in one orbit noted on initial examination, but only 2 were recessed in the first surgery. A second surgery addressed the third muscle. One patient had a hypertropia treated with bilateral inferior rectus recession; the hypertropia persisted nearly unchanged after the first surgery with severe limitation of downgaze in that eye. Another patient had an esotropia and one tight inferior rectus. We recessed one medial and one inferior rectus, and the
Journal of AAPOS
20 30 40 50 Preoperative deviation (prism diopters)
60
70
FIG 1. Horizontal muscles: millimeters of recession (total for all horizontal muscles recessed) versus preoperative deviation. Amount of recession performed in millimeters versus the measured preoperative angle of horizontal strabismus in prism diopters. Group 1 includes all patients with horizontal strabismus who had excellent or good outcomes after just one surgery. Group 2 includes patients who required more than one surgery or had a poor final outcome. Nomogram data includes data for esotropia and exotropia surgeries and is therefore not completely linear.9
patient developed vertical diplopia. Five patients were initially undercorrected; of those 5 undercorrected patients, 2 had more millimeters of recession when our method was used than what would have been prescribed by traditional nomograms, and 3 had less millimeters of recession. After one surgery, 41 of 58 patients (71%) had good or excellent outcomes. The final outcome was good or excellent in 52 (90%). Only one patient developed diplopia after having been diplopia-free at 2 month’s follow-up. Final outcomes were as follows: of the 58 patients, 48 (83%) had an excellent outcome, 4 (7%) had a good outcome, and 6 (10%) had a poor outcome. Of those with poor final outcomes, one had diplopia only in reading position and 2 had no diplopia with prism glasses (.10D).
Discussion Here we present results that are comparable with those of other series, and these results support the concept that the intraoperative relaxed muscle positioning technique is a good approach for TED patients. Some series have reported good results using surgical nomograms published for pediatric strabismus patients, but results from other series are mixed. Nomograms created for pediatric strabismus seem intuitively ill-suited to the TED population. Furthermore, the nomogram-based approach is particularly unhelpful when treating vertical deviations caused by bilateral inferior rectus restriction.
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Table 3. Analysis for factors predictive of the need for repeat surgery
Group 1 (R² = 0.723) 14
Group 2 (R² = 0.121)
Amount of recession (mm)
12
Analysis for factors predictive of the need for repeat surgery
Nomogram (R² = 1.00)
10 8 6 4 2 0 0
10
20
30
40
50
-2 -4 Preoperative deviation (prism diopters)
FIG 2. Vertical muscles: millimeters of recession (total for all vertical muscles recessed) versus preoperative deviation. Amount of recession performed in millimeters versus the measured preoperative angle of vertical strabismus in prism diopters. Group 1 includes all patients with vertical strabismus who had excellent or good outcomes after just one surgery. Group 2 includes patients who required more than one surgery or had a poor final outcome. Negative values reflect cases in which bilateral inferior rectus recession was performed with a larger recession in the unexpected eye.
Nguyen and colleagues7 and Thomas and Cruz8 have reported on techniques similar to ours with comparable results. Our technique differs from these in several respects. We fully relieve the restriction in each recessed muscle rather than trying to match the restriction in the contralateral eye. We operate through a fornix incision. Finally, we resuture the muscle to the globe with the eye in primary position rather than attempt to match the intraoperative eccentric position of the contralateral eye. Nguyen and colleagues had a 74% success rate (n 5 39) with one surgery. Their results are perhaps buoyed by their exclusion of patients who had repeat surgeries in the first 30 postoperative days and their lack of assessment for diplopia in reading position. Thomas and Cruz had a 66% success rate (n 5 47) in their duction correction group but also did not comment on diplopia in reading position.8 If we apply the same definition of success as these 2 studies, our success rate after one surgery was 74%. Reoperation rates for the three reports would be as follows: Nguyen and colleagues 27%, Thomas and Cruz 18%, and 21% for the present series. Our series reports a relatively long follow-up period, and this allows for analysis of ultimate outcomes. Ninety percent of our patients eventually had a successful outcome. Among those that required a second surgery, the rate of successful outcomes was also relatively high (85%). The need for a second surgery should therefore not be seen as a predictor of failure. We encountered 2 special circum-
Single vs multiple treatments for hyperthyroidism (multiple treatment modalities associated with $2 surgeries) Horizontal muscles vs vertical vs both Bilateral surgery vs unilateral Nature of treatment for hyperthyroidism $3 line asymmetry in visual acuity Presence of refractive error (those with no significant refractive error required more surgeries) Myopia vs hyperopia Prior orbital decompression Bilateral vs unilateral decompression Diplopia before decompression vs after Diplopia before decompression vs all others (diplopia before decompression associated with greater rate of second surgery) Vertical strabismus vs horizontal vs mixed Primarily horizontal strabismus versus primarily vertical (those with primarily horizontal strabismus were more likely to undergo reoperation) Monocular surgery vs binocular Angle of horizontal strabismus (all patients with horizontal strabismus included: those with larger angles more likely to undergo reoperation) Angle of vertical strabismus (all patients with vertical strabismus included) Age at diagnosis Number of muscles operated Hertel asymmetry Hertel change with decompression
P value 0.03a 0.15b 0.62a 0.14b 0.49a 0.09a 0.22b 0.12a 0.63a 0.27a 0.05b 0.12b 0.04a 0.53a 0.03c 0.64c 0.75c 0.29c 0.73c 0.63c
a
Fisher exact test. c test. c Unpaired t test. b 2
stances that led to reoperation more than once in this series. First, the treatment of a large-angle esotropia may unmask a smaller-angle vertical deviation and necessitate more surgery. Second, patients with three restricted muscles in one eye will require multiple surgeries to prevent anterior segment ischemia. Published success rates for deviation-based or nomogram-based strabismus repairs in TED patients vary between 38%3 and 82%,5 and reoperation rates range from 5% to 45%.3,10 Adjustable suture techniques in some series have provided a comparable success rate to ductionbased surgery,2,5 but the duction-based techniques obviate the need for postoperative manipulation. Factors that may have been predictive of the need for reoperation included: (1) multiple treatment modalities for Graves disease; (2) diplopia before orbital decompression; (3) primarily horizontal strabismus; and (4) larger angles of strabismus in the horizontal plane; however, each will require further investigation for confirmation. Perhaps more relevant were the numerous preoperative factors that did not correlate with a need for reoperation (Table 3). Our data set did not support the initial findings of Dal Canto and colleagues6 that patients who developed
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diplopia only after orbital decompression tended to require less surgery and have better outcomes. References 1. Lueder GT, Scott WE, Kutschke PJ, Keech RV. Long-term results of adjustable suture surgery for strabismus secondary to thyroid ophthalmopathy. Ophthalmology 1992;99:993-7. 2. Inoue Y, Tsuboi T, Kouzaki A, Maeda T, Inoue T. Ophthalmic surgery in dysthyroid ophthalmopathy. Thyroid 2002;12:257-63. 3. Kraus DJ, Bullock JD. Treatment of thyroid ocular myopathy with adjustable and nonadjustable suture strabismus surgery. Trans Am Ophthalmol Soc 1993;91:67-79. Discussion 79-84. 4. Evans D, Kennerdell JS. Extraocular muscle surgery for dysthyroid myopathy. Am J Ophthalmol 1983;95:767-71.
5. Flanders M, Hastings M. Diagnosis and surgical management of strabismus associated with thyroid-related orbitopathy. J Pediatr Ophthalmol Strabismus 1997;34:333-40. 6. Dal Canto AJ, Crowe S, Perry JD, Traboulsi EI. Intraoperative relaxed muscle positioning technique for strabismus repair in thyroid eye disease. Ophthalmology 2006;113:2324-30. 7. Nguyen VT, Park DJ, Levin L, Feldon SE. Correction of restricted extraocular muscle motility in surgical management of strabismus in graves’ ophthalmopathy. Ophthalmology 2002;109:384-8. 8. Thomas SM, Cruz OA. Comparison of two different surgical techniques for the treatment of strabismus in dysthyroid ophthalmopathy. J AAPOS 2007;11:258-61. 9. Wright KW, Ryan SJ. Color atlas of ophthalmic surgery. Philadelphia, PA: Lippincott; 1991. 10. Dyer JA. The oculorotary muscles in Graves’ disease. Trans Am Ophthalmol Soc 1976;74:425-56.
An Eye on the Arts—The Arts on the Eye “Even after her cornea transplant, Mammachi could only see light and shadow. If somebody was standing in the doorway, she could tell that someone was standing in the doorway. But not who it was. She could read a cheque, or a receipt, or a bank note only if it was close enough for her eyelashes to touch it. She would then hold it steady, and move her eye along it. Wheeling it from word to word. The Townspeople (in her fairy frock) saw Mammachi draw Sophie Mol close to her eyes to look at her. To read her like a cheque. To check her like a bank note. Mammachi (with her better eye) saw redbrown hair (N. Nalmost blond), the curve of two fatfreckled cheeks (Nnnn. almost rosy), bluegreyblue eyes.” — Arundhati Roy (from The God of Small Things, India Ink, New Delhi, India, 1997)
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