T IP A RAŞTIRMALARI A RŞİVİ

(1)

|

5 www.armedin.org

R E S E A R C H A R T I C L E

T ^IP A RAŞTIRMALARI A ^RŞİVİ

VOLUME 2 • NUMBER 1 • SEPTEMBER 2017

A B S T R A C T

Objective: To evaluate the surgical results of recessions with loop in esotropia and exotropia Patients and Methods: The charts of 32 patients, who had strabismus surgery (horizontal rectus muscles resection and/or recession combined with loop recession of the horizontal rectus muscles) for esotropias or exotropias measuring 50 PD or more, were reviewed retrospectively. Surgical success was defined as ortophoria within 10 PD of deviation.

Results: Thirteen patients had surgery for exodeviation and 19 patients had surgery for esodeviation. In patient with exotropia, mean preoperative deviation was 69.2 PD, mean postoperative deviation was 4.6 PD, the mean surgical alignment was 64.6 PD. In patient with esotropia, mean preoperative deviation was 68.4 PD, mean postoperative deviation was 6.8 PD.

The mean surgical alignment was 61.5 PD. The overall success rate was 75% (73% in esotropia group, 76% in exotropia group).

Conclusion: Loop recession is a effective and relatively easy technique for large angle strabismus.

Key words: Loop recessions, esotropia, exotropia, surgical outcome

Ö Z E T

Amaç: Ezotropya ve ekzotropya tedavisinde askılı geriletme cerrahisi sonuçlarının değerlendirilmesi

Yöntemler: 50 prizm diyoptri (PD) veya üzeri ezotropya veya ekzotropyası olan ve bu nedenle şaşılık cerrahisi uygulanmış (horizontal rektus kaslarına reseksiyon ve/veya geriletme ile kombine bu kaslardan birine askılı geriletme cerrahisi) 32 hastanın muayene kartları geriye dönük incelendi. 10 PD ve altı kayma miktarları cerrahi başarı olarak kabul edildi.

Bulgular: 13 hastaya ekzotropya cerrahisi, 19 hastaya ezotropya cerrahisi uygulanmıştı.

Ekzotropyası olan hastalarda ameliyat öncesi ortalama kayma miktarı 69,2 PD iken ameliyat sonrası ortalama kayma 4,6 PD, ortalama cerrahi düzeltme 64,6 PD idi. Ezotropyası olan hastalarda ameliyat öncesi ortalama kayma miktarı 68,4 PD iken ameliyat sonrası ortalama kayma 6,8 PD, ortalama cerrahi düzeltme 61,5 PD idi. Genel başarı oranı % 75 (% 73 ezotropya grubunda, % 76 ekzotropya grubunda) idi.

Sonuç: Geniş açılı şaşılık tedavisinde askılı geriletme etkili ve nispeten kolay bir tekniktir.

Anahtar kelimeler: Askılı geriletme, ezotropya, ekzotropya, cerrahi sonuçlar

INTRODUCTION

Tendon lengthening procedures; adjustable suture, loop recession and hemi-hang back recession are used to get surgical alignment in

large angle strabismus. The first surgeon who described a technique for increasing the effect of a horizontal muscle recession was Gobin [1]. He called his procedure a ‘loop recession’.

Clark and coworkers achieved successful results by using the same technique [2]. They emphasized

Surgical Outcomes of Loop Recession in Large Angle Strabismus

Geniş Açılı Şaşılıkta Askılı Geriletme Cerrahisi Sonuçları

Sinan Bilgin¹, İbrahim Türker², Süleyman Sami İlker³, Mehmet Fatih Ballı⁴, Şaban Kılıç⁵

1 Medifema Hospital, Izmir, Turkey

2 Department of Ophthalmology, Van Training and Research Hospital, Van, Turkey

3,4,5 Department of Ophthalmology,

Hafsa Sultan Hospital, Celal Bayar University, Faculty of Medicine, Manisa, Turkey

Address for correspondence:

Sinan Bilgin, MD

Medifema Hospital, Torbalı, Ayrancılar, Izmir, Turkey,

E-mail: drsinanbilgin@yahoo.com

Geliş Tarihi / Received: 10.07.2017, Kabul Tarihi/Accepted: 31.08.2017 Doi: 10.5799/10.5799/ahinjs.03.2017.01.007

(2)

Outcomes of Loop Recession in Strabismus

6

|

that this procedure should be considered for patients who were unsuitable for conventional recession or resection procedures.

Potter et al [3]. also suggested a similar technique (hemi-hang back recession) in cases of non-paralytic, large angle deviation, which generally require more than 7 mm recession for correction.

The cut-off point for large angle strabismus differs between various reviewers. Livir-Rallatos et al. accepted 35 prism diopters (PD), Millan et al. 40 PD, Scott et al. 50 PD and Lau et al. 60 PD of deviations[4-7]. The amount of surgery is well defined up to 50 PD deviations [8-11]. The options beyond this deviation are varied like two muscle, three muscle or four muscle surgeries.

However, larger amounts of recessions performed without causing significant limitation of ocular movements which believed to compromise long term stability, but there remains apprehension regarding the predictability of the postoperative results in large- angle strabismus [12,13].

In this case series we purposed to evaluate the outcomes of loop recession in patients who had large angle esotropia and exotropia more than 50 PD.

PATIENTS AND METHODS

The notes of all patients, who had strabismus surgery between 2005 and 2011 for esotropias or exotropias measuring 50 PD or more, were examined retrospectively. Patients were included in the study if they had a postoperative follow-up at least 3months.

Patients were excluded if they had incomitant strabismus, unreliable measurements, previous strabismus surgery, refractive component and inferior oblique over action. The following data were collected from all charts: patient age and sex, acuity with refractive error corrected, preoperative and postoperative strabismus measurements, details of the type of surgery performed, surgical alignment and surgical success rates. Surgical success was defined as ortophoria within 10 PD of deviation.

All strabismus measurements were taken in the primary position and the 6 cardinal positions with the patient fixating on an object approximately 5 m away. Near measurements were performed with the patient fixating at one-third m. Measurements were done by prism and alternate cover test. If cover tests were not possible due to inability to cooperate, in poor vision and young age Krimsky test or the Hirschberg corneal reflex test were employed.

Esotropia patients had 6 mm unimedial or bimedial rectus recession (≤ 3 years 6mm, older age 7 mm) and 3 or 4 mm loop recession, exotropia patients had 6.5 mm unilateral or bilateral lateral rectus recession and 3 or 4 mm loop recession. In addition to this, some patients had medial or lateral rectus resection.

Surgical technique: A limbal conjunctival incision was used in order to reach rectus muscles. The muscle was isolated from the surrounding Tenon’s capsule. Two preplaced 6-0 polyglycolic acid sutures (Pegelak, Trabzon, Turkey) placed through the both

side of muscle tendon near the insertion and the sutures tied.

The muscle was disinserted from the globe. Before cutting, a 5-0 silk suture passed through the muscle for safety 5 mm posterior from the insertion. In the conventional method, after measuring the amount of recession with caliper, both spatulated needles passed from the sclera at two points and tied. In the loop recession method, both sutures tied over a probe with a circumference of 6 or 8 mm and muscles hung on bare sclera. The conjunctiva was sutured with 8-0 polyglycolic acid suture (Surgilactin, UK).

RESULTS

Three hundred patients who underwent surgical correction of exodeviation or esodeviation were identified. Thirty-two of them who had exo or eso deviations from 50 PD to 90 PD and met the inclusion criteria were accepted for the study. Thirteen patients had surgery for exodeviation and 19 patients had surgery for esodeviation. The median age was 23 years old in exotropia group and 3.5 years old in esotropia group. The mean age was 23 in exotropia group and 5 in esotropia group.

In patients with exotropia, mean preoperative deviation was 69.2 PD, mean postoperative deviation was 4.6 PD, the mean surgical alignment was 64.6 PD. Ten patients had both recession and resection. Three patient had bilateral recession. Mean recession was 9.9 mm with loop. Mean 3.52 PD surgical alignment (range from 2.5 to 4.8) has obtained for each on millimeter recession.

In patients with esotropia, mean preoperative deviation was 68.4 PD, mean postoperative deviation was 6.8 PD. The mean surgical alignment was 61.5 PD. Six patients had both recession and resection. Thirteen patients had bimedial recession. Mean recession was 9.6 mm with loop. Mean 3.18 PD surgical alignment (range from 2.1 to 4.4) has obtained for each one-millimeter recession.

The overall success rate was 75% (73% in esotropia group, 76% in exotropia group). Follow-up ranged from 3 months to 48 months, with a median follow-up of 12 months. No patient lost any lines of visual acuity on follow-up. An overcorrection has not been identified.

DISCUSSION

The surgical outcome of large-angle strabismus is suboptimal with a single procedure. Recession with a loop was firstly described by Gobin. The muscle was reattached to the sclera posterior to the original insertion and suspended with loops. Gobin believed a connective tissue bridge; a pseudotendon, would form between the scleral attachment side and the cut, free-hanging tendon edge, the pseudotendon maintaining an arc of contact between the muscle and globe. The effects of procedure were evaluated in 94 cases, and 75 of 94 cases were had postoperative alignments within 15 PD of straight [1]. Lang supported this theory and

(3)

Outcomes of Loop Recession in Strabismus

|

7 www.armedin.org

reported that if the loops were inserted in front of the functional equator they adhered to the sclera and the advantage of using them was negated[14]. Although it has some little differences, Potter et al. described a similar technique which they called

‘hemi-hang back’ and they reported successful results [3].

The distance from the midpoint of the rectus muscle tendons to the limbus varies but generally is approximately 5.7 mm (4.5–7.5) and 7.5 mm (6–9) for the medial and lateral rectus muscles [15-17]. An arc of contact is formed between the point of tangency and the anatomic insertion. For the medial and lateral rectus, the arc of contact averages between 6.0 mm and 7.0 mm[18]. As the globe rotates, the arc of contact shortens on the side of muscle contraction; this place the anatomic insertion closer to the functional point of tangency. There is a progressive loss of torque as the insertion moves beyond the point of tangency, such that ocular rotations become limited. For example, 7 mm recession of the medial rectus would result in a 25% to 30%

reduction in ocular rotation into the field of action of the muscle [19]. However, studies have shown that larger recessions from 8 to 11 mm can be performed without significant reduction in abduction[20,21]. Our experiments showed that greater recessions more than 6-7 mm for medial rectus and 6.5 mm for lateral rectus, can cause adduction and abduction defects. So, we prefer to use these dimensions in recessions.

In additionally, it is observed that surgical success was acquired when same amounts of recessions with loops was applied for the patients with different preoperative deviations. For example, the patients with 50 PD and 80 PD preoperative deviations has got the same 6 mm recessions with 4 mm loops and they are both ortophoric. We suppose that ortophoria is decisive. In other words, free side of muscle attach to the sclera in orthophoric position of the globe. In conclusion, loop recession is a useful and relatively easy technique for large angle strabismus. It decreases the necessary of a second surgery or third-muscle surgery.

Conflict of Interests: The authors declare that they have no conflict of interest.

Financial Disclosure: No financial support was received.

Çıkar Çatışması Beyanı: Yazarlar çıkar çatışması olmadığını bildirmişlerdir.

Finansal Destek: Bu çalışma için herhangi bir finansal destek alınmamıştır.

REFERENCES

1. Gobin MH. Recession of the medial rectus muscle with a loop.

Ophtalmologica 1968;156:25-7.

2. Clark DI, Markland S, Trimble RB. A study to assess the value of dacron slings in the management of squints which are not amenable to conventional surgery. Br. J. Ophtalmol 1986;70:623-9.

3. Potter WS 3rd, Nelson LB, Handa JT. Hemihang-back recession:

description of the technique and review of the literature. Ophthalmic Surg 1990;21:711-5.

4. Livir-Rallatos G, Gunton KB, Calhoun JH. Surgical results in large-angle exotropia. J AAPOS 2002;6:77−80.

5. Millan T, de Carvalho KM, Minguini N. Results of monocular surgery under peribulbar anesthesia for large-angle horizontal strabismus. Clinics 2009;64:303−308.

6. Scott WE, Reese PD, Hirsh CR, Flabetich CA. Surgery for large-angle congenital esotropia. Arch. Ophthalmol 1986;104:374−377.

7. Lau FH, Fan DS. Surgical outcome of single-staged three horizontal muscles squint surgery for extra-large angle exotropia. Eye (Lond) 2010;24:1171-6.

8. Parks MM. Concomitant esodeviations. In: Clinical Ophthalmology.Vol.

1, 12. Philadelphia, PA: Harper & Row, 1984:10.

9. Parks MM. Concomitant exodeviations. In: Clinical Ophthalmology. Vol.

1, 13. Philadelphia, PA: Harper & Row, 1984; 1, Chapter 12: 9.

10. Scott AB, Mash A. J, Jampolsky A. Quantitative guidelines for exotropia surgery. Invest Ophthalmol Vis Sci 1975;14:428−36.

11. Simon JW, Buckley EG, Drack AV et al. Basic and clinical science course, Section 6, 2005-2006, Pediatric ophthalmology and strabismus. San Francisco, CA: American Academy of Ophthalmology 2005:171−2.

12. Damanakis AG, Arvanitis PG, Ladas ID et al. 8 mm bimedial rectus recession in infantile esotropia of 80-90 prism diopters. Br J Ophthalmol 1994;78:842−4.

13. Vroman DT, Hutchinson AK, Saunders RA et al. Two muscle surgery for congenital esotropia: rate of reoperation in patients with small versus large angles of deviation. J AAPOS 2000;4:267−70.

14. Lang RM, Pearce WG. Muscle recession with a suture loop in rabbits.

Can J Ophtalmol 1980;15:84-6.

15. Bron AJ, Tripathi RC, Tripathi BJ: Wolff's Anatomy of the Eye and Orbit, 8th ed. London: Chapman & Hall, 1997.

16. Hogan M, Alvarado J, Weddell J: Histology of the Human Eye—An Atlas and Textbook. Philadelphia: WB Saunders, 1971.

17. Migliori ME, Gladstone GJ: Determination of the normal range of exophthalmometric values for black and white adults. Am J Ophthalmol 1984;98:438–442.

18. Goldstein HP, Scott AB, Nelson LB. Ocular motility. ln: Tasman W, Jaeger EA, eds. Duane’s Biomedical Foundations of Ophthalmology 2.

Philadelphia, PA: Lippincott;1989: 1-65.

19. Potter WS, Nelson LB. Suspension recession: hang-back and hemihang- back techniques in strabismus surgery. Semin Ophthalmol 1990;5:193- 201.

20. Schwartz RL, Calhoun JH. Surgery of large angle exotropia. J Pediatr Ophthalmol Strab. 1980;17: 359-363

21. Livir- Rallatos G, Gunton KB, Calhoun JH. Surgical results in large-angle exotropia. J AAPOS. 2002;6:77-80.