Al-Shifa Journal of Ophthalmology (ASJO)
|Aims and Scope||
Repair of Lost Medial Rectus after Pterygium Excision
Shehla Rubab, MBBS, MCPS, FCPS (Pak), Fellow of IACLE (Australia), Fellow in Pediatric Ophthalmology (Canada)
Purpose: To highlight the surgical complications of pterygium.
Study design: Case report.
Participant: A young male presenting with diplopia after ptreygium excision Discussion: Pterygium excision is a common and routine surgery being done in almost every eye care center. This simple procedure sometimes can result in a major complication like medial rectus disinsertion. This rare complication was seen in a young patient who presented with diplopia and exotropia after pterygium excision. On examination medial rectus muscle was found to be disinserted. The medial rectus was found and resutured. Binocular single vision was restored.Conclusion: Optimal management of pterygium requires an understanding for the anatomy, differential diagnosis, complications and treatment options. Al-Shifa Journal of Ophthalmology 2005; 1: 21-24 © Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan.
preferred method for removal and management of a pterygium remains
uncertain. The mere presence of a pterygium does not mandate its removal
if its natural course does not threaten the vision. If a patient is
selected for the surgery, the goal of the surgery should be effectively
removing the pterygium, obtain as good a visual result as possible and
to prevent complications. Disinsertion or damage to the rectus muscle
during pterygium excision is one of the major complications.
This results not only in diplopia, exotropia and scarring of the conjunctiva but also calls for the need of another more complicated surgery.
received: March 5, 2004
A 23 years male presented with complaint of diplopia for 01 week in pediatric and strabismus unit of Al-Shifa Trust eye hospital Rawalpindi. He had history of right pterygium excision 01 week before at a primary health care centre.On examination he had right exotropia of 50 prism diopters. Adduction in right eye was extremely limited. On slit lamp examination, right nasal conjunctiva was chemosed and congested. There was evidence of excision of pterygium along with a large piece of conjunctival tissue. The medial rectus muscle was found disinserted and only a residual small tendon at insertion site was exposed. At Al-Shifa, it was decided to re-operate. Medial rectus muscle was explored and identified and then was sutured back to its insertion site. Post-operatively patient became orthophoric with binocular single vision in the primary position. Abduction in right eye was slightly limited due to scarring and deficient conjunctival tissue. He experiences diplopia only in extreme right gaze due to inability to abduct his right eye fully.
Preoperative right exotropia Preoperative limitation in right adduction
Postoperative normal adduction
Although the prevalence of the lesion increases with age, the highest incidence occurs between the ages of 20 and 49. In temperate climates, primary pterygia rarely extend to the visual axis. Most pterygia are atrophic and inactive. Inactive pterygia are pale thin and membranous. An inactive lesion in a patient of any age should be left undisturbed. Patients who have such lesions should be provided with explanations, reassurance and periodic observations and should be discouraged from having surgery. Some clinicians in Israel have essentially given up excising pterygia of any size because of poor results and complications despite the careful use of excellent surgical techniques. They concluded that it is preferable to observe ptyregia until they threaten the visual axis and then perform corneal transplantation1. Such an extreme approach is not appropriate for most parts of the world, but it does emphasize the need for caution. The following guidelines are acceptable indications for the surgical removal of the pterygia.
1. Advancement of an active pterygium to or beyond a point halfway between the limbus and the visual axis.
2. Obvious progression of a bothersome and worrisome ptyregium.
3. A need to correct complications such as symblepheron and restricted motility.
4. Decreased visual acuity due to pterygium induced astigmatism.
Occasionally to eliminate symptoms such as foreign body sensation and mild
Mild symptoms of photophobia and injection from a small pterygium can often be managed by avoiding smoke and dust-filled environments. Topical preservative-free lubricants, vasoconstrictors, and mild corticosteroids can safely relieve symptoms when used judiciously. To prevent progression, some authors have advocated the use of ultraviolet-blocking spectacles. Both UV-A and UV-B protection have been recommended by Taylor and associates based on the results of their epidemiologic study2.
The first report of a surgical treatment of pterygium by Susrata is more than 3000 years old3. Many variations of this procedure since that time have been published. These include Avulsion, Excision (bare sclera), Excision with primary closure, Transplantation of the head of the pterygium and Limbal auto graft. Adjunctive therapy has also been tried which include Application of Cautry after excising pterygia, Laser Therapy, Corticosteroids, Thiotepa, Mitomycin C, and Beta Radiation.The number of procedures described attest to the fact that pterygia pose difficult management problems and an optimal procedure still has not been found. Surgery for the pterygium excision can result in many complications like recurrence (common
and worse than primary lesion)4, excessive granulation tissue formation, dellen, scleral melting due to cautry or beta irradiation, corneal perforation, scleral perforation, symblepheron formation, inadvertent disinsertion of medial rectus, lenticular opacities after beta radiation application, conjunctival irritation and injection, bacterial super-infection, permanent eye lid depigmentation after thio-tepa application and corneal melting, corneal edema, local ischemia, glaucoma, sudden onset cataract,uveitis, scleral calcification and intractable pain with and without photophobia.
The decision to operate for pterygia can be difficult and must be tempered by the understanding that it can result in complications. All complications that may occur at surgery can be avoided with proper care. During pterygium excision care should be taken not to cut the insertion of the rectus muscle or leave it exposed. Inadvertent disinsertion of the medial rectus muscle has been reported particularly with resection of large or recurrent pterygia. Identification and isolation of the rectus muscle tendon and insertion prior to dissection can prevent this complication. Tenon capsule and muscle insertion should not be left exposed because this can lead to the production of excessive granulation tissue and subsequent recurrence of pterygium5.
Every pterygium does not need excision. Pterygium should be excised
only when it is of progressive type and is approaching visual axis.
1. Youngson R M: Recurrence of pterygium after excision. Br J Ophthalmol 56:120,1972.
2. Taylor HR, West SK, Rosenthal FS et al: Corneal changes associated with chronic UV irradiation. Arch Ophthalmol 107:1481, 1989
3. Rosenthal JW: Chronology of pterygium therapy. Am J Ophthalmol 36:1601, 1953.
4. Paton D: Pterygium management based upon a theory of pathogenesis. Trans Am Acad, 1984.
5. Raab EL, Metz HS, Ellis FD: Medial rectus injury after pterygium excision . Arch Ophthalmol 107:1428,1989