Nelson: Our topic is reoperations in strabismus. The first patient is a 6-month-old girl who had esotropia of 60 prism diopters (PD) and a refractive error of +1. She had a recession of each medial rectus muscle of 6.5 mm. Two months postoperatively, she has an esotropia of 25 PD. How would you manage this?
Brown: There are several ways to approach reoperation on an incompletely treated strabismus. In this situation, I would repeat a cycloplegic refraction. If there is an excessive hyperopic error, then I would prescribe glasses and schedule a follow-up examination in 2 to 3 months to remeasure the strabismus. If there is a preference for either eye, I would initiate amblyopia treatment. If further strabismus surgery is then indicated, I would resect both lateral rectus muscles.
Friedman: I agree with Dr. Brown's approach. I might also take into account cosmesis and see how the child looks. Sometimes parents are reluctant to return to the operating room 2 months later. If they are comfortable with the cosmesis, I might wait to see what happens. If I do a second procedure, it would also be a bilateral lateral rectus resection.
Madigan: I would definitely reoperate. If I operated on the bimedial rectus muscle the first time, I would do a bilateral lateral rectus resection. This is not uncommon with these larger deviations. I tell the family that we're almost there and we've got to get all of the way there.
Nelson: The second case is a 10-year-old boy with esotropia of 30 PD who had a 4.5-mm recession of the right medial rectus muscle and an 8-mm resection of the right lateral rectus muscle. At 9 months postoperatively, the child has an exotropia of 20 PD and visual acuity of 20/25 in the right eye and 20/20 in the left eye.
Friedman: Given his good vision, it is unlikely that glasses would make a significant difference. At this age, he might also have diplopia. I think this would require a reoperation. I would recess the right lateral rectus muscle and then consider whether to do the left. There may be enough room to get him where he needs to be with the right muscle alone.
Madigan: My first choice would be to do a right lateral rectus recession for the maximum amount of 10 or 12 mm.
Brown: There is no significant hyperopia or other new issue?
Brown: Then I agree that a recession of the right lateral rectus muscle for a 20 PD deviation is a prudent choice.
Nelson: The next case is a boy with an esotropia of 50 PD who had a recession of both medial rectus muscles of 6 mm. At 3 months postoperatively, he had an exotropia of 30 PD and underwent a bilateral lateral rectus recession of 7 mm. Now at 6 months postoperatively, he has an esotropia of 30 PD and a refractive error of +1.
Madigan: I would first explain to the family that unfortunately their child just does not have any peripheral fusion. He's not going to be a monofixator and has no ability to stabilize his alignment. I can mechanically put his eyes straight, but probably it's not going to hold up. Having said that, I would tell the family I've known patients who go through life getting surgical adjustments. It is almost like a dampening oscillating curve because the swings are much less with each subsequent surgery in my experience.
Nelson: So what surgery would you perform?
Madigan: I would advance both lateral muscles.
Brown: I would likely do the same. The parents are of course disappointed, and the situation is always unfortunate. I typically tell parents initially that we expect one operation to be all that is required, but that in some cases two or even three surgeries may be needed. Our goals are good vision, binocularity, and normal appearance/motility. With normal ocular anatomy and good timing, we typically are successful long term.
Friedman: I agree. Managing expectations is important. Even if the child is a little esotropic after the third surgery, I think we can hold onto that. In this case, I would do gentle bilateral laterals.
Nelson: The next patient is an 8-year-old girl with an exotropia of 30 PD who had 8-mm recession of both lateral rectus muscles. Postoperatively, she had an esotropia of 25 PD. She had a 4-mm recession of both medial rectus muscles and now presents 6 to 8 months later with an exotropia of 15 PD.
Brown: She is asymptomatic with no diplopia? Does she look exotropic?
Nelson: The parents are bothered by it enough that they came back to you. She is getting teased at school.
Brown: At 6 to 8 months, we likely have given enough time to deem the strabimus stable. I would reoperate and advance at least one medical rectus muscle. An exaggerated response to the initial surgery has occurred and I would consider this in the approach to further treatment.
Friedman: I agree. I would not be overly aggressive. If you do more than one medial rectus advancement, I think it would end up on the other side of the pendulum again.
Madigan: I have to agree as well.
Nelson: The next case is a man with a sensory exotropia of 40 PD. The patient had an 8-mm recession of the right lateral rectus muscle and a 6-mm resection of the right medial rectus muscle. At 4 months later, he has an exotropia of 20 PD and poor visual acuity of 20/200 in the right eye.
Friedman: I spend a lot of time on refraction before surgery in these patients. A lot of people think they have much poorer vision than they really do. At 4 months, this is the borderline of when I would consider reoperating. I would have a frank conversation with the patient about the limitations of what we can do. I think there's a little room here to potentially try more resection and maybe a little more recession if we can. At this point, our goal is cosmesis or alignment rather than functional improvement. We don't want to risk his good eye.
Nelson: Would you operate on both muscles?
Friedman: With 20 PD, I would have to see how far back I can get that lateral muscle. If I can't get back to 11 or 12 mm, I'm not sure 2 mm is really going to do the trick in that patient and I also may have to do a little more resection on the medial rectus muscle.
Brown: If the patient is still bothered and we agree that a reoperation is needed, I would do two muscles again. I would explore the lateral rectus muscle to determine if it is attached at the expected recessed location. I would do an additional recession based on this, for a total of 11 to 12 mm.
Nelson: And at the same time do a small resection?
Brown: Yes, I would re-resect the medial if the patient appears to have 20 PD of residual exotropia.
Madigan: I know we all feel the same way, that it's hard to do less than a 3-mm resection. When you look at it, you'll have an idea of whether you can resect any more of the medial rectus muscle.
Nelson: So what would you do here?
Madigan: I would see how elastic the muscle was and decide how much I thought I could re-sect reasonably. Then I would do 3 mm on the additional resection and 12 mm on the lateral rectus muscle. If I felt like I had gotten everything I could out of that medial rectus muscle, I'd back off and just do 12 mm on the lateral rectus muscle.
Brown: That is a good point. We have seen these patients become esotropic. Although a small angle overcorrection may be acceptable, there is a risk of restriction.
Madigan: People do look a little better esotropic. If you're reoperating more for their overall appearance, you're going to tend toward the esotropic side.
Friedman: Yes, because otherwise they'll just drift right back out.
Nelson: The last patient is an 8-month-old male infant with congenital exotropia of 55 PD. He had a 9-mm recession of both lateral rectus muscles. At 9 or 10 months postoperatively, he has an exotropia of 25 PD.
Friedman: I would not be completely surprised. In my experience, a deviation of more than 50 PD can be unpredictable as to whether that 9-mm recession is going to give you what you want. At this point, I would do a resection on the medial rectus muscles in both eyes. Just doing one eye may result in more problems later.
Madigan: To begin with, I would not have done surgery on an 8-month-old child. I usually wait until the child is 1 year old. We know 2 years is really the target if you want to have their eyes aligned in time for the binocular portion to be able to develop.
Nelson: Some of the data indicate that it's not so much the age of the child but the duration of the strabismus.
Madigan: I still think operating that early is somewhat controversial. There has been a lot of media attention on the risks of anesthesia for infants, so families will often want to wait until at least 1 year. I think 13 or 14 months is ideal because by 14 or 15 months the children can become orthophoric.
Nelson: If this patient was 1 year old with 55 PD of exotropia, what would you do?
Madigan: A bimedial resection.
Brown: Given the circumstances of this case, I would resect both muscles. The comments regarding anesthesia have validity. I have a candid discussion with parents who raise this issue. We talk about the pros and cons of anesthesia and its effects and the goals of proper vision development and binocular vision development.
Friedman: I also delay primary surgery for esotropias and exotropias. Based on the existing data, I don't feel comfortable recommending surgery for very young children.
Brown: I recall one patient who had a large angle exotropia in infancy with a refractive error of +6. The angle of deviation did not change with glasses correction initially. We had decided to pursue surgical intervention and on a preoperative evaluation he was orthophoric. He later ended up requiring surgery but the strabismus varied in type and amount over time.
Nelson: Presented with +6, I think most of us would have tried glasses rather than surgery and then reevaluate.
Madigan: Back in the 1980s, many surgeons were doing bimedial 7-mm recessions for large esotropias at 6 months of age thinking that earlier and more surgery was better, but many of the patients came back a few years later with large exotropias. So we all moved away from that.
Nelson: Thank you all for your insights on this topic.
This Eye to Eye session was conducted on Sunday, March 18, 2018, during the annual meeting of the American Association for Pediatric Ophthalmology and Strabismus in Washington, DC.