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Unilateral versus bilateral medial rectus recession
Unilateral Versus Bilateral Medial Rectus Recession Rebecca R. Stack, MBChB,a Celeste D. Burley, BAppSc(Orth),a Antony Bedggood, MBChB,a and Mark J. Elder, MBChB, MD, FRACOb Background: Unilateral medial rectus recession is suitable for some cases of small-angle deviation in esotropia. This approach limits surgery to one eye, leaves other muscles untouched, and should be quicker than bilateral muscle surgery. This study compared the results of a range of medial rectus recessions, both unilateral and bilateral, performed by one surgeon. Methods: Data were collected on all pediatric patients who had undergone medial rectus recession, unilateral and bilateral, performed by one surgeon between August 1, 1995, and March 31, 2002. Postoperative deviations were calculated from the short- (2 to 8 weeks) and long-term (6 to 48 months) follow-up visits. Results: Medial rectus recessions were performed on 107 patients, 56 unilateral and 51 bilateral. After exclusions were made, 45 (80%) of the unilateral procedures and 41 (80%) of the bilateral cases were studied. At long-term follow-up, the mean prism diopter (PD) change in deviation per millimeter recessed (at distance) for unilateral recessions of 5 mm, 6 mm, 7 mm, and 8 mm were 2.3, 2.2, 2.3, and 2.5, respectively. For equivalent bilateral recessions the mean changes in deviation were 4.2, 4.0, 4.3, and 5.0 PD/mm. Conclusion: Unilateral medial rectus recession is a predictable method for surgical correction of small-angle pediatric esotropia. The change in deviation per millimeter of recession after unilateral recession is significantly less than that obtained from equivalent amounts of bilateral recession (P ⬍ .01). (J AAPOS 2003;7:263–267) ilateral medial rectus recession is a common surgical approach for correction of esotropia. Unilateral rectus muscle surgery has been proposed as an alternative in some cases of small-angle deviation1-6 and has several theoretical advantages over bilateral surgery. These include the following: anesthetic time and postoperative pain are decreased; the risk of complications is limited to one eye only; and untouched muscles are available if further surgery is needed for residual esotropia. The procedure should be quicker than bilateral surgery. This study aimed to determine the change in deviation obtained, per millimeter of medial rectus recession, in unilateral operations performed by one surgeon. A comparison was made between the change in deviation achieved per millimeter recessed between unilateral and bilateral medial rectus recessions.
B
METHODS This is a retrospective series of single and bilateral horizontal muscle squint surgeries performed by one surgeon on consecutive pediatric patients between August 1, 1995,
From the Department of Ophthalmology,a Christchurch Hospital, Christchurch, and the Christchurch School of Medicine,b University of Otago, Dunedin, New Zealand. Submitted July 30, 2002. Revisions accepted April 18, 2003. Reprint requests: Mark Elder, MBChB, MD, FRACO, Ophthalmology Department, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand. Copyright © 2003 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2003/$35.00 ⫹ 0 doi:10.1016/S1091-8531(03)00117-4
Journal of AAPOS
and March 31, 2002. Cases were identified using the hospital computerized coding system for strabismus surgery. Patients ranged from 1 to 14 years of age at the time of surgery (mean, 4.1 years for unilateral and 3.1 years for bilateral). One hundred seven medial rectus recessions were performed, 56 unilateral and 51 bilateral, on patients with esotropia during this period. Patients with all types of esotropia were included. Patients were excluded if they had previous medial rectus surgery (n ⫽ 2), Duane Syndrome (n ⫽ 1), Brown Syndrome (n ⫽ 1), or if there were insufficient data from follow-up visits (n ⫽ 14). Patients were not excluded for unsuccessful amblyopia therapy, cerebral palsy, or previous surgery on other extraocular muscles (n ⫽ 7 in the unilateral group). There were no cases of consecutive esotropia. This left a series of 45 patients (80%) with unilateral recessions and 41 patients (80%) with bilateral recessions. One experienced orthoptist or the operating surgeon measured all deviations using the Alternate Prism Cover Test at near and distance (with spectacle correction if spectacles were worn), Hirschberg’s corneal reflex test, or Krimsky’s test as appropriate for the cooperation level of the patient. Preoperative measurements were made at a pr-admission visit no more than 10 days before surgery. Fifteen patients (n ⫽ 10 for unilateral and n ⫽ 5 for bilateral) had been prescribed glasses before surgery. The correction worn ranged from ⫹3.50 to ⫹8.0 diopters (spherical equivalent), which was calculated after cycloplegic retinoscopy with 1% cyclopentolate or 1% atropine. August 2003
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TABLE 1. Preoperative deviations and postoperative change in deviation for each patient after unilateral medial rectus recession Net change Long-term† Short-term* Preop Preop distance deviation Long-term deviation Short-term deviation deviation Amount of deviation distance deviation distance deviation near distance Patient recession (PD) (PD) near (PD) (PD) near (PD) (PD) (PD) no. (mm) 1‡ 2 3 4‡ 5‡ 6 7 8 9 10 11 12 13‡ 14‡ 15 16 17 18 19 20 21 22 23 24 25 26‡ 27 28 29 30‡ 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
5§ 5 (gls) 5 5 5.5 6 (gls) 6 6§ 6 6 (gls) 6 6 (gls) 6 (gls) 6 6.5 6.5 7 7 (gls) 7 7 7 7 (gls) 7 7 7 7 7 7.5 7.5 8 8§ 8 8 (gls) 8 8 (gls) 8 8 8 8 8§ 8§ 8 (gls) 8 8 8
10 4 10 20 25 15 15 6 45 15 10 12 2 30 30 35 25 10 20 30 20 12 45 12 15 30 25 40 40 20 30 35 20 20 20 20 30 30 30 35 30 4 25 45 25
10 12 10 30 30 15 15 15 45 15 45 20 2 20 30 35 25 20 30 35 35 30 45 25 20 30 20 40 40 20 30 35 25 20 25 20 35 30 30 35 30 20 25 50 25
⫺12 3 NA 12 10 0 3 NA 15 10 4 10 NA 6 NA 15 13 4 12 8 10 6 25 9 0 15 10 NA NA 10 20 5 2 5 5 ⫺5 20 10 10 NA NA NA 10 NA NA
⫺12 2 NA 5 5 8 9 NA 15 5 25 14 NA 10 0 15 13 12 12 10 15 15 25 15 0 20 10 10 NA 10 20 5 20 15 5 ⫺5 20 10 10 10 10 NA 10 NA 5
⫺5 5 6 2 NA 0 3 9 20 7 5 5 0 0 NA 3 5 ⫺15 0 0 5 3 20 8 NA 12 7 NA 5 5 20 0 8 0 0 0 15 10 3 NA 15 NA 10 5 5
⫺5 3 4 2 5 5 7 20 20 12 5 5 0 0 NA 5 5 ⫺6 10 0 5 5 20 5 5 20 10 5 5 5 20 0 15 0 0 0 15 10 3 10 20 5 10 5 5
15 7 4 18 NA 15 12 15 25 8 5 7 2 30 NA 32 20 25 20 30 15 9 25 4 NA 18 18 NA 35 15 10 35 12 20 20 20 15 20 27 NA 15 NA 15 40 20
Long-term follow-up (mo) 11 15 18 11 12 15 18 15 9 14 18 18 10 6 NA 24 14 18 18 6 11 18 6 12 10 48 7 18 15 12 24 18 14 18 6 29 10 15 6 12 11 6 15 12 12
*Short-term follow-up was at the first postoperative visit (2 to 6 weeks). †Last follow-up visit (before additional surgery if performed) was at 6 to 60 months. ‡⫽ Patient had previous surgery but not on the operative muscle. §⫽ Patient went on to have further surgery. Data given prior to further surgery. PD, prism diopters; gls, patient wore glasses; NA, data not available for given field.
There were no myopic patients in this series. No alteration of spectacle correction was made after surgery to enhance the result, and no patient not wearing spectacles before surgery was prescribed spectacles after surgery. All operations analyzed in this series were medial rectus recessions, unilateral and bilateral. All surgeries were per-
formed under general anaesthetic by one surgeon. All incisions were limbal, with recession of the conjunctiva, and the muscles were tied with interrupted 6/0 Vicryl (Ethicon, Somerville, NJ) sutures on a spatulated needle. Recessions were measured from the tendon insertion using calipers, and no hang-back or adjustable sutures were used.
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TABLE 2. Preoperative deviations and postoperative change in deviation for each patient after bilateral medial rectus recession Net change Long-term† Short-term* Preop Preop distance deviation Long-term deviation Short-term deviation deviation Amount of deviation distance deviation distance deviation near distance Patient recession (PD) (PD) near (PD) (PD) near (PD) (PD) (PD) no. (mm) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
4.5 4.5 (gls) 4.5 4.5 4.5 4.5 4.5‡ 4.5 5 5 5 (gls) 5 5 5 5‡ 5‡ 5‡ 5 5 5.5 5.5 (gls) 5.5 5.5 5.5 (gls) 6 6 6 6 6 6 6.5‡ 6.5 6.5 7 7 7 7.5‡ 7.5 7.5 8 (gls)
50 16 40 25 40 40 40 45 50 50 45 NA NA 40 35 45 40 50 50 40 50 30 55 30 55 60 NA 60 NA 50 NA 65 NA 72 70 60 80 NA 80 80
45 18 40 35 40 45 35 35 60 50 45 50 50 40 45 55 45 40 50 45 50 45 55 30 60 60 47 60 60 50 70 65 60 72 70 70 90 80 80 80
5 6 NA 20 12 0 12 20 20 20 4 NA NA 10 6 35 25 15 10 20 3 NA 12 7 7 12 NA 25 NA 3 NA 20 NA 30 0 30 0 NA NA NA
5 7 25 25 12 0 20 25 20 20 4 20 20 10 10 35 30 15 10 25 3 0 12 7 7 12 7 25 20 3 ⫺3 20 0 30 0 40 0 10 0 0
5 3 12 3 7 0 15 3 ⫺7 10 4 NA NA 0 NA 35 ⫺20 10 5 10 3 ⫺7 10 0 15 7 NA 10 NA 5 NA 0 NA 12 ⫺2 20 ⫺7 NA NA 0
5 3 12 3 7 3 30 3 ⫺7 10 4 7 0 0 ⫺40 35 ⫺20 0 5 10 3 ⫺7 10 3 10 7 12 10 15 5 ⫺12 0 ⫺3 12 0 10 ⫺7 ⫺7 3 0
45 13 28 22 33 40 10 42 57 40 41 NA NA 40 NA 10 60 40 45 30 47 37 45 30 45 53 NA 50 NA 45 NA 65 NA 60 72 50 87 NA NA 80
265
Long-term follow-up (mo) 11 12 12 38 26 72 12 9 27 12 36 8 35 11 26 22 6 24 13 6 18 12 24 6 12 32 30 15 9 17 6 16 18 18 11 10 18 17 12 6
*Short-term follow-up was at the first postoperative visit (2 to 6 weeks). †Last follow-up visit (before additional surgery if performed) was at 6 to 60 months. ‡Patient had additional surgery. PD, prism diopters; gls, patient wore glasses; NA, data not available for given field.
No other devices were used. Muscles were recessed between 4.5 mm and 8 mm according to the preoperative corrected distance deviation. Complete details of the number and degree of recessions performed are given in Table 1. Inferior oblique tenotomies and myectomies were performed in some patients who had inferior oblique overaction. These cases were included because this procedure is not believed to alter the deviation in primary position of gaze.7 The short-term postoperative information was taken at the first postoperative visit with complete documentation
of the angle of deviation by the same orthoptist or the operating surgeon. All short-term assessments occurred between 2 and 8 weeks after surgery. Long-term follow-up was the last measurement of alignment recorded or alignment made before any further surgery was performed. These measurements were recorded by the same orthoptist or the operating surgeon. Follow-up varied from 6 months to 5 years, with mean follow-up at 13.7 months for the unilateral group and 18.1 months for the bilateral group, which is not statistically significant (P ⫽ .1).
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TABLE 3. Summary of results showing the mean postoperative change in deviation and correction per millimeter recessed for unilateral and bilateral medial rectus recessions Type of recession Unilateral
Bilateral
Amount of recession (mm)
No. in sample
Mean change in deviation short-term* distance (PD)
Mean change in deviation long-term† distance (PD)
5 6 7 8 4.5 5.0 5.5 6.0 7.0
4 9 11 16 8 11 5 6 3
11.0 ⫾ 10.7 13.4 ⫾ 11.3 12.0 ⫾ 6.0 19.0 ⫾ 6.4 25.9 ⫾ 14.5 28.9 ⫾ 10.4 33.3 ⫾ 13.7 44.5 ⫾ 6.4 47.3 ⫾ 20.5
11.5 ⫾ 6.6 13.2 ⫾ 9.3 16.4 ⫾ 7.7 20.3 ⫾ 8.5 29.1 ⫾ 13.2 41.6 ⫾ 15.1 37.8 ⫾ 8.0 48.3 ⫾ 3.9 60.7 ⫾ 11.0
PD/mm of recession (PD/mm)‡ 11.5/5 ⫽ 2.3 13.2/6 ⫽ 2.2 16.4/7 ⫽ 2.3 20.3/8 ⫽ 2.5 29.1/9 ⫽ 3.2 41.6/10 ⫽ 4.2 37.8/11 ⫽ 3.5 48.3/12 ⫽ 4.0 60.7/14 ⫽ 4.3
*Short-term follow-up was at the first postoperative visit (2 to 6 weeks). †Last follow-up visit (before additional surgery if performed) was at 6 to 60 months. ‡This figure was calculated from the long-term distance figures. PD, prism diopter.
TABLE 4. Results of change in deviation per millimeter of recession for unilateral and bilateral medial rectus recessions Amount of recession (mm)
Unilateral recession (PD/mm)
Bilateral recession (PD/mm)
5 6 7 8
2.3 2.2 2.3 2.5
4.2 4.0 4.3 5.0*
*A single case. PD, prism diopters.
RESULTS Table 1 gives the preoperative deviations for all cases of unilateral medial rectus recession. It also documents the postoperative short-term and long-term changes in deviation (measured at near and distance). Table 2 gives the same information for the bilateral recessions. Tables 1 and 2 indicate the deviation at the longest follow-up period for each case and include details of residual esodeviation, consecutive exodeviation, and orthophoria. Table 3 is a summary table comparing the unilateral and bilateral groups and indicating the mean postoperative change in deviation. Data for the long-term distance change in deviation achieved per millimeter of recession are also included. Groups with the same amount of recession are compared. Data were not included for the patients with 5.5-mm (n ⫽ 1), 6.5-mm (n ⫽ 2), and 7.5-mm (n ⫽ 2) recessions because these groups were too small to give statistically significant information. However, these data are shown in Table 1. A comparison between the PD change in deviation per millimeter recessed for the unilateral and bilateral cases of medial rectus recession is presented in Table 4. There were no immediate or long-term surgical complications, and no muscles were “lost” during or after surgery. Three cases of conjunctival inclusion cysts developed after surgery. We graded limitation of adduction on a scale of 0 to ⫺4, with 0 being full and ⫺4 being no movement beyond
midline. For unilateral recessions, seven patients had some limitation. The amounts of the limitation and muscle recession were, respectively, as follows: ⫺0.5, 5 mm; ⫺0.5, 8 mm; ⫺0.5, 6 mm; ⫺1, 5 mm; ⫺1, 6 mm; ⫺1, 7 mm; and ⫺2, 6 mm. After surgery, five patients who underwent bilateral recession developed limited adduction. The amounts of limitation and recession were as follows: ⫺0.5, 6 mm; ⫺1, 5 mm; ⫺1, 7mm; ⫺2, 6 mm; and ⫺1, 6 mm. Five unilateral cases, three with 8-mm medial rectus recessions, went on to have additional surgery because of residual esodeviation. Six cases from the bilateral group had additional surgery because of residual esodeviation (n ⫽ 1) or consecutive exodeviation (n ⫽ 5). Therefore, the reoperation rates in this series for unilateral and bilateral surgery were 4 of 45 (9%) and 6 of 41 (15%), respectively, which is not statistically significant (P ⫽ .62 chi square with Yates correction). Case no. 15 in the bilateral group had 45 PD of consecutive exotropia after surgery, which required reoperation. The medial rectus muscles were found in the expected position at surgery.
DISCUSSION Unilateral muscle recessions have been reported in the literature from as early as 1951, when Stine1 reported 14 cases of medial rectus recession. Muscles were moved to the equator, and the average correction was 13.6 PD at distance and 16.1 PD at near. Small-angle esotropia of 18 PD or less corrected with unilateral rectus muscle recession have been reported to give an average correction of 11.3 PD for distance and 10.7 PD for near.2 Kaiser3 reported a series of 12 adult cases of esotropia corrected by unilateral medial rectus recession, all of which showed “definite improvement.” More recently, Grin and Nelson8 found large unilateral medial rectus recession to be an effective and safe method of treating moderate-angle esotropia. They found the average correction from a 6-mm recession to be 21 PD and from a 6.5-mm recession to be 27 PD. In a series of 53
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TABLE 5. Results of bilateral medial rectus recession from the literature Amount of recession (mm) 5 6 7 8*
Change in deviation (PD): Parks (2001)11
Change in deviation (PD): Nelson (1987)12
30 40 60
35 50 75⫹
Average change in deviation (PD): Parks and Nelson
Average change in deviation/mm of recession (PD/mm): Parks and Nelson
Average change in deviation/mm of recession (PD/mm): Present study
32.5 45.0 67.5 71.4
32.5/10 ⫽ 3.3 45.0/12 ⫽ 3.8 67.5/14 ⫽ 4.8 71.4/16 ⫽ 4.5
39.8/10 ⫽ 4.2 48.3/12 ⫽ 4.0 60.7/14 ⫽ 4.3 80/16 ⫽ 5.0†
*These figures are from Damanakis et al.13 †Result of a single case. PD, prism diopter.
patients9 with 14 to 20 PD of esotropia, 6-mm unilateral medial rectus recessions were performed. The average correction measured 16 PD, and all had less than 10 PD of deviation at last follow-up. Twenty-five patients with high accommodative convergence/accommodation ratios (AC/A) and near esotropia of 15 to 35 PD were treated with 6- to 8-mm unilateral medial rectus recessions, and 24 of 25 (95%) patients were reported to have alignment within 10 PD at long-term follow-up.10 Bilateral medial rectus recessions have been well described in the literature and remain a common surgical method of correcting esotropia. High success rates have been reported with bilateral medial recessions in patients with esotropia of varying angles. Commonly accepted recommendations for bilateral medial rectus recessions are 5 mm, 6 mm, and 7 mm for surgical correction of esotropia (Table 5). 11-13 The amount of safe recession of the horizontal rectus muscles has been debated, but it is now accepted that recession beyond the traditional 5 mm is successful for large-angle deviations.14,15 Recession of medial rectus muscles as much as 8 mm is uncommonly reported; the results given are those of a single series reported by Damanakis et al.13 This series shows the results of one surgeon’s pediatric series of unilateral and bilateral medial rectus recessions. One orthoptist or the operating surgeon performed the measurements. We found that unilateral medial rectus recessions resulted in a linear amount of correction in PD per millimeter for all amounts of recession. A 5-mm recession of one medial rectus resulted in a mean of 2.3 PD of correction/mm recessed, and an 8-mm recession resulted in a mean of 2.5 PD of correction/mm (Table 3). Bilateral medial rectus recessions also showed a linear relationship between the amount of correction achieved per millimeter recessed and the amount of the recession. The correction was 4.2 PD/mm for 5-mm recessions and 5.0 PD/mm for the single 8.0-mm recession performed. For all values of recession there is a statistically significant difference between the change in deviation for unilateral and bilateral medial rectus recessions (P ⬍ .001). The mean change in deviation short-term was 13.7 ⫾ 7.8 PD and long-term was 17.9 ⫾ 9.2 PD, which showed a statistically significant increase in effect over time (P ⫽ .04). For the bilateral recessions, the short-term change in deviation was 35.1 ⫾ 16.4 PD, and the long-term change was 43.9 ⫾
18.1 PD, which was a significant increase in effect with time (P ⫽ .05). Unilateral medial rectus recession is a predictable means of treating esotropia, although the equivalent change in deviation achieved per millimeter is smaller than that observed for bilateral recessions (P ⬍ .01 for each group). A 6-mm unilateral recession resulted in 2.2 PD/ mm, a 13.2 PD total change in deviation on average. A bilateral 6-mm recession resulted in 4.0 PD/mm, a 48 PD total change in deviation on average. Unilateral medial rectus recessions should be considered for esotropias ⬍ 25 PD. References 1. Steine G. The surgical treatment of esophoria. Am J Ophthalmol 1951;34:1307-13. 2. Pollard ZF, Manley DM. Unilateral medial rectus recession for small-angle esotropia. Arch Ophthalmol 1976;94:780-1. 3. Kaiser R. Surgery for esophoria in the adult. Am Orthop J 1957;7: 107-8. 4. Sheppard RW, Panton CM, Smith DR. The single horizontal recession operation. Can J Ophthalmol 1973;8:68-74. 5. Chamberlain W. The single medial rectus recession operation. J Paediatr Ophthalmol 1970;7:208-11. 6. De Decker W, Baenge JJ. Unilateral medial rectus recession in the treatment of small angle esodeviation. Graefes Arch Clin Exp Ophthalmol 1988;226:161-4. 7. Parks MM, Mitchell PR. A and V Patterns. In: Tasman W, Jaeger EA, editors. Duane’s clinical ophthalmology. Philadelphia (PA): Harper and Row; 1991. 8. Grin TR, Nelson LB. Large unilateral medial rectus recession for the treatment of esotropia. Br J Ophthalmol 1987;71:377-9. 9. Zak TA. Results of large single medial rectus recession. J Pediatr Ophthalmol Strabismus 1986;23:17-21. 10. Procianoy E, Justo DM. Results of unilateral medial rectus recession in high AC/A ratio esotropia. J Pediatr Ophthalmol Strabismus 1991;28:212-4. 11. Parks MM, Mitchell PR, Wheeler MB. Concomitant esodeviations. In: Tasman W, Jaeger EA, editors. Duane’s clinical ophthalmology [CD-ROM]. Philadelphia (PA): Harper and Row; 2001. 12. Nelson LB, Wagner RS, Simon JW, Harley RD. Congenital esotropia. Surv Ophthalmol 1987;31:363-83. 13. Damanakis AG, Arvanitis PG, Ladas ID, Theodossiadis GP. 8 mm bimedial rectus recession in infantile esotropia of 80-90 PDs. Br J Ophthalmol 1994;78:842-4. 14. Kushner BJ, Fisher MR, Lucchese NJ, Morton GV. How far can a medial rectus be safely recessed? J Pediatr Ophthalmol Strabismus 1994;31:138-46. 15. Hess JB, Calhoun JH. A new rationale for the management of large angle esotropia. J Pediatr Ophthalmol Strabismus 1979;16:345-8.
B
METHODS This is a retrospective series of single and bilateral horizontal muscle squint surgeries performed by one surgeon on consecutive pediatric patients between August 1, 1995,
From the Department of Ophthalmology,a Christchurch Hospital, Christchurch, and the Christchurch School of Medicine,b University of Otago, Dunedin, New Zealand. Submitted July 30, 2002. Revisions accepted April 18, 2003. Reprint requests: Mark Elder, MBChB, MD, FRACO, Ophthalmology Department, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand. Copyright © 2003 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2003/$35.00 ⫹ 0 doi:10.1016/S1091-8531(03)00117-4
Journal of AAPOS
and March 31, 2002. Cases were identified using the hospital computerized coding system for strabismus surgery. Patients ranged from 1 to 14 years of age at the time of surgery (mean, 4.1 years for unilateral and 3.1 years for bilateral). One hundred seven medial rectus recessions were performed, 56 unilateral and 51 bilateral, on patients with esotropia during this period. Patients with all types of esotropia were included. Patients were excluded if they had previous medial rectus surgery (n ⫽ 2), Duane Syndrome (n ⫽ 1), Brown Syndrome (n ⫽ 1), or if there were insufficient data from follow-up visits (n ⫽ 14). Patients were not excluded for unsuccessful amblyopia therapy, cerebral palsy, or previous surgery on other extraocular muscles (n ⫽ 7 in the unilateral group). There were no cases of consecutive esotropia. This left a series of 45 patients (80%) with unilateral recessions and 41 patients (80%) with bilateral recessions. One experienced orthoptist or the operating surgeon measured all deviations using the Alternate Prism Cover Test at near and distance (with spectacle correction if spectacles were worn), Hirschberg’s corneal reflex test, or Krimsky’s test as appropriate for the cooperation level of the patient. Preoperative measurements were made at a pr-admission visit no more than 10 days before surgery. Fifteen patients (n ⫽ 10 for unilateral and n ⫽ 5 for bilateral) had been prescribed glasses before surgery. The correction worn ranged from ⫹3.50 to ⫹8.0 diopters (spherical equivalent), which was calculated after cycloplegic retinoscopy with 1% cyclopentolate or 1% atropine. August 2003
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TABLE 1. Preoperative deviations and postoperative change in deviation for each patient after unilateral medial rectus recession Net change Long-term† Short-term* Preop Preop distance deviation Long-term deviation Short-term deviation deviation Amount of deviation distance deviation distance deviation near distance Patient recession (PD) (PD) near (PD) (PD) near (PD) (PD) (PD) no. (mm) 1‡ 2 3 4‡ 5‡ 6 7 8 9 10 11 12 13‡ 14‡ 15 16 17 18 19 20 21 22 23 24 25 26‡ 27 28 29 30‡ 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
5§ 5 (gls) 5 5 5.5 6 (gls) 6 6§ 6 6 (gls) 6 6 (gls) 6 (gls) 6 6.5 6.5 7 7 (gls) 7 7 7 7 (gls) 7 7 7 7 7 7.5 7.5 8 8§ 8 8 (gls) 8 8 (gls) 8 8 8 8 8§ 8§ 8 (gls) 8 8 8
10 4 10 20 25 15 15 6 45 15 10 12 2 30 30 35 25 10 20 30 20 12 45 12 15 30 25 40 40 20 30 35 20 20 20 20 30 30 30 35 30 4 25 45 25
10 12 10 30 30 15 15 15 45 15 45 20 2 20 30 35 25 20 30 35 35 30 45 25 20 30 20 40 40 20 30 35 25 20 25 20 35 30 30 35 30 20 25 50 25
⫺12 3 NA 12 10 0 3 NA 15 10 4 10 NA 6 NA 15 13 4 12 8 10 6 25 9 0 15 10 NA NA 10 20 5 2 5 5 ⫺5 20 10 10 NA NA NA 10 NA NA
⫺12 2 NA 5 5 8 9 NA 15 5 25 14 NA 10 0 15 13 12 12 10 15 15 25 15 0 20 10 10 NA 10 20 5 20 15 5 ⫺5 20 10 10 10 10 NA 10 NA 5
⫺5 5 6 2 NA 0 3 9 20 7 5 5 0 0 NA 3 5 ⫺15 0 0 5 3 20 8 NA 12 7 NA 5 5 20 0 8 0 0 0 15 10 3 NA 15 NA 10 5 5
⫺5 3 4 2 5 5 7 20 20 12 5 5 0 0 NA 5 5 ⫺6 10 0 5 5 20 5 5 20 10 5 5 5 20 0 15 0 0 0 15 10 3 10 20 5 10 5 5
15 7 4 18 NA 15 12 15 25 8 5 7 2 30 NA 32 20 25 20 30 15 9 25 4 NA 18 18 NA 35 15 10 35 12 20 20 20 15 20 27 NA 15 NA 15 40 20
Long-term follow-up (mo) 11 15 18 11 12 15 18 15 9 14 18 18 10 6 NA 24 14 18 18 6 11 18 6 12 10 48 7 18 15 12 24 18 14 18 6 29 10 15 6 12 11 6 15 12 12
*Short-term follow-up was at the first postoperative visit (2 to 6 weeks). †Last follow-up visit (before additional surgery if performed) was at 6 to 60 months. ‡⫽ Patient had previous surgery but not on the operative muscle. §⫽ Patient went on to have further surgery. Data given prior to further surgery. PD, prism diopters; gls, patient wore glasses; NA, data not available for given field.
There were no myopic patients in this series. No alteration of spectacle correction was made after surgery to enhance the result, and no patient not wearing spectacles before surgery was prescribed spectacles after surgery. All operations analyzed in this series were medial rectus recessions, unilateral and bilateral. All surgeries were per-
formed under general anaesthetic by one surgeon. All incisions were limbal, with recession of the conjunctiva, and the muscles were tied with interrupted 6/0 Vicryl (Ethicon, Somerville, NJ) sutures on a spatulated needle. Recessions were measured from the tendon insertion using calipers, and no hang-back or adjustable sutures were used.
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TABLE 2. Preoperative deviations and postoperative change in deviation for each patient after bilateral medial rectus recession Net change Long-term† Short-term* Preop Preop distance deviation Long-term deviation Short-term deviation deviation Amount of deviation distance deviation distance deviation near distance Patient recession (PD) (PD) near (PD) (PD) near (PD) (PD) (PD) no. (mm) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
4.5 4.5 (gls) 4.5 4.5 4.5 4.5 4.5‡ 4.5 5 5 5 (gls) 5 5 5 5‡ 5‡ 5‡ 5 5 5.5 5.5 (gls) 5.5 5.5 5.5 (gls) 6 6 6 6 6 6 6.5‡ 6.5 6.5 7 7 7 7.5‡ 7.5 7.5 8 (gls)
50 16 40 25 40 40 40 45 50 50 45 NA NA 40 35 45 40 50 50 40 50 30 55 30 55 60 NA 60 NA 50 NA 65 NA 72 70 60 80 NA 80 80
45 18 40 35 40 45 35 35 60 50 45 50 50 40 45 55 45 40 50 45 50 45 55 30 60 60 47 60 60 50 70 65 60 72 70 70 90 80 80 80
5 6 NA 20 12 0 12 20 20 20 4 NA NA 10 6 35 25 15 10 20 3 NA 12 7 7 12 NA 25 NA 3 NA 20 NA 30 0 30 0 NA NA NA
5 7 25 25 12 0 20 25 20 20 4 20 20 10 10 35 30 15 10 25 3 0 12 7 7 12 7 25 20 3 ⫺3 20 0 30 0 40 0 10 0 0
5 3 12 3 7 0 15 3 ⫺7 10 4 NA NA 0 NA 35 ⫺20 10 5 10 3 ⫺7 10 0 15 7 NA 10 NA 5 NA 0 NA 12 ⫺2 20 ⫺7 NA NA 0
5 3 12 3 7 3 30 3 ⫺7 10 4 7 0 0 ⫺40 35 ⫺20 0 5 10 3 ⫺7 10 3 10 7 12 10 15 5 ⫺12 0 ⫺3 12 0 10 ⫺7 ⫺7 3 0
45 13 28 22 33 40 10 42 57 40 41 NA NA 40 NA 10 60 40 45 30 47 37 45 30 45 53 NA 50 NA 45 NA 65 NA 60 72 50 87 NA NA 80
265
Long-term follow-up (mo) 11 12 12 38 26 72 12 9 27 12 36 8 35 11 26 22 6 24 13 6 18 12 24 6 12 32 30 15 9 17 6 16 18 18 11 10 18 17 12 6
*Short-term follow-up was at the first postoperative visit (2 to 6 weeks). †Last follow-up visit (before additional surgery if performed) was at 6 to 60 months. ‡Patient had additional surgery. PD, prism diopters; gls, patient wore glasses; NA, data not available for given field.
No other devices were used. Muscles were recessed between 4.5 mm and 8 mm according to the preoperative corrected distance deviation. Complete details of the number and degree of recessions performed are given in Table 1. Inferior oblique tenotomies and myectomies were performed in some patients who had inferior oblique overaction. These cases were included because this procedure is not believed to alter the deviation in primary position of gaze.7 The short-term postoperative information was taken at the first postoperative visit with complete documentation
of the angle of deviation by the same orthoptist or the operating surgeon. All short-term assessments occurred between 2 and 8 weeks after surgery. Long-term follow-up was the last measurement of alignment recorded or alignment made before any further surgery was performed. These measurements were recorded by the same orthoptist or the operating surgeon. Follow-up varied from 6 months to 5 years, with mean follow-up at 13.7 months for the unilateral group and 18.1 months for the bilateral group, which is not statistically significant (P ⫽ .1).
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TABLE 3. Summary of results showing the mean postoperative change in deviation and correction per millimeter recessed for unilateral and bilateral medial rectus recessions Type of recession Unilateral
Bilateral
Amount of recession (mm)
No. in sample
Mean change in deviation short-term* distance (PD)
Mean change in deviation long-term† distance (PD)
5 6 7 8 4.5 5.0 5.5 6.0 7.0
4 9 11 16 8 11 5 6 3
11.0 ⫾ 10.7 13.4 ⫾ 11.3 12.0 ⫾ 6.0 19.0 ⫾ 6.4 25.9 ⫾ 14.5 28.9 ⫾ 10.4 33.3 ⫾ 13.7 44.5 ⫾ 6.4 47.3 ⫾ 20.5
11.5 ⫾ 6.6 13.2 ⫾ 9.3 16.4 ⫾ 7.7 20.3 ⫾ 8.5 29.1 ⫾ 13.2 41.6 ⫾ 15.1 37.8 ⫾ 8.0 48.3 ⫾ 3.9 60.7 ⫾ 11.0
PD/mm of recession (PD/mm)‡ 11.5/5 ⫽ 2.3 13.2/6 ⫽ 2.2 16.4/7 ⫽ 2.3 20.3/8 ⫽ 2.5 29.1/9 ⫽ 3.2 41.6/10 ⫽ 4.2 37.8/11 ⫽ 3.5 48.3/12 ⫽ 4.0 60.7/14 ⫽ 4.3
*Short-term follow-up was at the first postoperative visit (2 to 6 weeks). †Last follow-up visit (before additional surgery if performed) was at 6 to 60 months. ‡This figure was calculated from the long-term distance figures. PD, prism diopter.
TABLE 4. Results of change in deviation per millimeter of recession for unilateral and bilateral medial rectus recessions Amount of recession (mm)
Unilateral recession (PD/mm)
Bilateral recession (PD/mm)
5 6 7 8
2.3 2.2 2.3 2.5
4.2 4.0 4.3 5.0*
*A single case. PD, prism diopters.
RESULTS Table 1 gives the preoperative deviations for all cases of unilateral medial rectus recession. It also documents the postoperative short-term and long-term changes in deviation (measured at near and distance). Table 2 gives the same information for the bilateral recessions. Tables 1 and 2 indicate the deviation at the longest follow-up period for each case and include details of residual esodeviation, consecutive exodeviation, and orthophoria. Table 3 is a summary table comparing the unilateral and bilateral groups and indicating the mean postoperative change in deviation. Data for the long-term distance change in deviation achieved per millimeter of recession are also included. Groups with the same amount of recession are compared. Data were not included for the patients with 5.5-mm (n ⫽ 1), 6.5-mm (n ⫽ 2), and 7.5-mm (n ⫽ 2) recessions because these groups were too small to give statistically significant information. However, these data are shown in Table 1. A comparison between the PD change in deviation per millimeter recessed for the unilateral and bilateral cases of medial rectus recession is presented in Table 4. There were no immediate or long-term surgical complications, and no muscles were “lost” during or after surgery. Three cases of conjunctival inclusion cysts developed after surgery. We graded limitation of adduction on a scale of 0 to ⫺4, with 0 being full and ⫺4 being no movement beyond
midline. For unilateral recessions, seven patients had some limitation. The amounts of the limitation and muscle recession were, respectively, as follows: ⫺0.5, 5 mm; ⫺0.5, 8 mm; ⫺0.5, 6 mm; ⫺1, 5 mm; ⫺1, 6 mm; ⫺1, 7 mm; and ⫺2, 6 mm. After surgery, five patients who underwent bilateral recession developed limited adduction. The amounts of limitation and recession were as follows: ⫺0.5, 6 mm; ⫺1, 5 mm; ⫺1, 7mm; ⫺2, 6 mm; and ⫺1, 6 mm. Five unilateral cases, three with 8-mm medial rectus recessions, went on to have additional surgery because of residual esodeviation. Six cases from the bilateral group had additional surgery because of residual esodeviation (n ⫽ 1) or consecutive exodeviation (n ⫽ 5). Therefore, the reoperation rates in this series for unilateral and bilateral surgery were 4 of 45 (9%) and 6 of 41 (15%), respectively, which is not statistically significant (P ⫽ .62 chi square with Yates correction). Case no. 15 in the bilateral group had 45 PD of consecutive exotropia after surgery, which required reoperation. The medial rectus muscles were found in the expected position at surgery.
DISCUSSION Unilateral muscle recessions have been reported in the literature from as early as 1951, when Stine1 reported 14 cases of medial rectus recession. Muscles were moved to the equator, and the average correction was 13.6 PD at distance and 16.1 PD at near. Small-angle esotropia of 18 PD or less corrected with unilateral rectus muscle recession have been reported to give an average correction of 11.3 PD for distance and 10.7 PD for near.2 Kaiser3 reported a series of 12 adult cases of esotropia corrected by unilateral medial rectus recession, all of which showed “definite improvement.” More recently, Grin and Nelson8 found large unilateral medial rectus recession to be an effective and safe method of treating moderate-angle esotropia. They found the average correction from a 6-mm recession to be 21 PD and from a 6.5-mm recession to be 27 PD. In a series of 53
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TABLE 5. Results of bilateral medial rectus recession from the literature Amount of recession (mm) 5 6 7 8*
Change in deviation (PD): Parks (2001)11
Change in deviation (PD): Nelson (1987)12
30 40 60
35 50 75⫹
Average change in deviation (PD): Parks and Nelson
Average change in deviation/mm of recession (PD/mm): Parks and Nelson
Average change in deviation/mm of recession (PD/mm): Present study
32.5 45.0 67.5 71.4
32.5/10 ⫽ 3.3 45.0/12 ⫽ 3.8 67.5/14 ⫽ 4.8 71.4/16 ⫽ 4.5
39.8/10 ⫽ 4.2 48.3/12 ⫽ 4.0 60.7/14 ⫽ 4.3 80/16 ⫽ 5.0†
*These figures are from Damanakis et al.13 †Result of a single case. PD, prism diopter.
patients9 with 14 to 20 PD of esotropia, 6-mm unilateral medial rectus recessions were performed. The average correction measured 16 PD, and all had less than 10 PD of deviation at last follow-up. Twenty-five patients with high accommodative convergence/accommodation ratios (AC/A) and near esotropia of 15 to 35 PD were treated with 6- to 8-mm unilateral medial rectus recessions, and 24 of 25 (95%) patients were reported to have alignment within 10 PD at long-term follow-up.10 Bilateral medial rectus recessions have been well described in the literature and remain a common surgical method of correcting esotropia. High success rates have been reported with bilateral medial recessions in patients with esotropia of varying angles. Commonly accepted recommendations for bilateral medial rectus recessions are 5 mm, 6 mm, and 7 mm for surgical correction of esotropia (Table 5). 11-13 The amount of safe recession of the horizontal rectus muscles has been debated, but it is now accepted that recession beyond the traditional 5 mm is successful for large-angle deviations.14,15 Recession of medial rectus muscles as much as 8 mm is uncommonly reported; the results given are those of a single series reported by Damanakis et al.13 This series shows the results of one surgeon’s pediatric series of unilateral and bilateral medial rectus recessions. One orthoptist or the operating surgeon performed the measurements. We found that unilateral medial rectus recessions resulted in a linear amount of correction in PD per millimeter for all amounts of recession. A 5-mm recession of one medial rectus resulted in a mean of 2.3 PD of correction/mm recessed, and an 8-mm recession resulted in a mean of 2.5 PD of correction/mm (Table 3). Bilateral medial rectus recessions also showed a linear relationship between the amount of correction achieved per millimeter recessed and the amount of the recession. The correction was 4.2 PD/mm for 5-mm recessions and 5.0 PD/mm for the single 8.0-mm recession performed. For all values of recession there is a statistically significant difference between the change in deviation for unilateral and bilateral medial rectus recessions (P ⬍ .001). The mean change in deviation short-term was 13.7 ⫾ 7.8 PD and long-term was 17.9 ⫾ 9.2 PD, which showed a statistically significant increase in effect over time (P ⫽ .04). For the bilateral recessions, the short-term change in deviation was 35.1 ⫾ 16.4 PD, and the long-term change was 43.9 ⫾
18.1 PD, which was a significant increase in effect with time (P ⫽ .05). Unilateral medial rectus recession is a predictable means of treating esotropia, although the equivalent change in deviation achieved per millimeter is smaller than that observed for bilateral recessions (P ⬍ .01 for each group). A 6-mm unilateral recession resulted in 2.2 PD/ mm, a 13.2 PD total change in deviation on average. A bilateral 6-mm recession resulted in 4.0 PD/mm, a 48 PD total change in deviation on average. Unilateral medial rectus recessions should be considered for esotropias ⬍ 25 PD. References 1. Steine G. The surgical treatment of esophoria. Am J Ophthalmol 1951;34:1307-13. 2. Pollard ZF, Manley DM. Unilateral medial rectus recession for small-angle esotropia. Arch Ophthalmol 1976;94:780-1. 3. Kaiser R. Surgery for esophoria in the adult. Am Orthop J 1957;7: 107-8. 4. Sheppard RW, Panton CM, Smith DR. The single horizontal recession operation. Can J Ophthalmol 1973;8:68-74. 5. Chamberlain W. The single medial rectus recession operation. J Paediatr Ophthalmol 1970;7:208-11. 6. De Decker W, Baenge JJ. Unilateral medial rectus recession in the treatment of small angle esodeviation. Graefes Arch Clin Exp Ophthalmol 1988;226:161-4. 7. Parks MM, Mitchell PR. A and V Patterns. In: Tasman W, Jaeger EA, editors. Duane’s clinical ophthalmology. Philadelphia (PA): Harper and Row; 1991. 8. Grin TR, Nelson LB. Large unilateral medial rectus recession for the treatment of esotropia. Br J Ophthalmol 1987;71:377-9. 9. Zak TA. Results of large single medial rectus recession. J Pediatr Ophthalmol Strabismus 1986;23:17-21. 10. Procianoy E, Justo DM. Results of unilateral medial rectus recession in high AC/A ratio esotropia. J Pediatr Ophthalmol Strabismus 1991;28:212-4. 11. Parks MM, Mitchell PR, Wheeler MB. Concomitant esodeviations. In: Tasman W, Jaeger EA, editors. Duane’s clinical ophthalmology [CD-ROM]. Philadelphia (PA): Harper and Row; 2001. 12. Nelson LB, Wagner RS, Simon JW, Harley RD. Congenital esotropia. Surv Ophthalmol 1987;31:363-83. 13. Damanakis AG, Arvanitis PG, Ladas ID, Theodossiadis GP. 8 mm bimedial rectus recession in infantile esotropia of 80-90 PDs. Br J Ophthalmol 1994;78:842-4. 14. Kushner BJ, Fisher MR, Lucchese NJ, Morton GV. How far can a medial rectus be safely recessed? J Pediatr Ophthalmol Strabismus 1994;31:138-46. 15. Hess JB, Calhoun JH. A new rationale for the management of large angle esotropia. J Pediatr Ophthalmol Strabismus 1979;16:345-8.