Journal of Pediatric Ophthalmology and Strabismus

Anterior Segment Ischemia Following Strabismus Surgery

John W Simon, MD; Elaine C Price, BA; Gregory B Krohel, MD; Robert W Poulin, MD; Robert D Reinecke, MD

Abstract

SUMMARY

Anterior segment ischemia (ASI) is a potentially blinding complication of extensive eye muscle surgery. Eyes have been described with this complication following surgery on as few as two rectus muscles, especially in patients with thyroid dysfunction or other medical illnesses. In an attempt to assess the risk of ASI, we have reviewed the records of 34 eyes in 26 patients who underwent surgery on three or four rectus muscles. Seven eyes of six patients with thyroid ophthalmopathy which underwent two- or threemuscle surgery were also studied. Evidence of clinically significant ASI was apparent in only one patient during a follow-up period of seven months to eleven years. This case was mild and no visual toss resulted. Our findings suggest that surgery on three or four rectus muscles in healthy patients is probably safe when performed in a staged fashion.

Abstract

SUMMARY

Anterior segment ischemia (ASI) is a potentially blinding complication of extensive eye muscle surgery. Eyes have been described with this complication following surgery on as few as two rectus muscles, especially in patients with thyroid dysfunction or other medical illnesses. In an attempt to assess the risk of ASI, we have reviewed the records of 34 eyes in 26 patients who underwent surgery on three or four rectus muscles. Seven eyes of six patients with thyroid ophthalmopathy which underwent two- or threemuscle surgery were also studied. Evidence of clinically significant ASI was apparent in only one patient during a follow-up period of seven months to eleven years. This case was mild and no visual toss resulted. Our findings suggest that surgery on three or four rectus muscles in healthy patients is probably safe when performed in a staged fashion.

Strabismus surgery involving detachment of the rectus tendons has occasionally been followed by anterior segment ischemia (ASI).1-6 Surgical manipulation of the extraocular muscles can interrupt flow through the seven anterior ciliary arteries, which course through them to provide a major vascular supply for the anterior ocular segment. Postoperative circulatory disturbances have been demonstrated using iris fluorescein angiography, which may show persistent segmental filling defects.6·7

The ischemie insult generally presents in the first few days following surgery with pain and decreased vision in the involved eye. Other reported findings include conjunctival injection, corneal edema and ulcération, iritis with stremai atrophy or ectopie pupil, cataract, hypotony, and even phthisis bulbi.1-4 Visual prognosis has varied from 20/20 to no light perception. Treatment with topical and systemic steroids is thought to favorably influence the course.

The association of ASI with muscle surgery is well established; however, the question of how many muscles can be removed with impunity remains unanswered. Surgery involving two rectus muscles has only rarely been reported to produce this complication.1 Fells and Marsh noted mild signs of ischemia in patients who had undergone simultaneous medial and inferior rectus recessions for thyroid ophthalmopathy.8 Jacobs, Vastine, and Urist reported a case of ASI following lateral rectus recession and medial rectus resection in a 69-year-old woman with chronic lymphocytic leukemia.9 This case, in which the white blood cell count was extremely high, led to speculation that patients with hyperviscosity syndromes or other blood dyscrasias may have an increased risk of ischemia following routine eye muscle surgery.9'11

Surgery on more than two rectus muscles has been more frequently associated with ASI.'-6 When surgery is planned on three or four rectus muscles of one eye, Krewson,12 Girard and Eeltranena,a and Harley13 suggest detaching no more than two per operation. An interim period of six weeks14 to four months13 is suggested between such procedures. One recent report suggested that the anterior ciliary circulation may never be restored after surgery and advised that at least one rectus muscle per eye should be permanently reserved to prevent this complication.1

Materials and Methods

We recently reviewed all records of eye muscle procedures for the past ten years at the Albany Medical College. Those patients whose total surgery involved three or four rectus muscles of the same eye were identified for study. Because of their apparent increased risk, patients with thyroid ophthalmopathy who underwent surgery on either two or three muscles were also included. We were particularly concerned with any clinical evidence of anterior segment inflammation, media opacity, or decreased visual acuity in the postoperative period. Adults underwent slit lamp examination at one and four to six weeks postoperatively. Children were routinely examined by flashlight. Follow-up ranged from seven months to 11 years.

Results

The study included 41 eyes of 32 patients. Nineteen eyes had surgery on three muscles (Table 1), 15 had surgery on four muscles (Table 2), and seven were eyes with thyroid ophthalmopathy which had surgery on two or three muscles (Table 3). In all but three cases (#5, #20, #271, surgery involved transections of the entire rectus tendons.

In the group of patients with three-muscle surgery, seven cases involved adults' eyes and 12 cases involved children's eyes. The interim between detachment of the first two muscles and the third muscle varied from three and a half., months to five years in the adults. Among children, there was one case of simultaneous three-muscle surgery (#5), and the longest interim period was 16 years.

The four-muscle surgery group included five adults' eyes and 10 children^ eyes. The time interval before detachment of the third or fourth rectus muscles varied from one to four months in adults and three months to seven and a half years in children.

Of the seven eyes with thyroid ophthalmopathy, four underwent simultaneous surgery on two rectus muscles. Three patients had surgery on three recti of the same eye at surgical procedures separated by seven-month intervals.

With the exception of thyroid dysfunction, there was no historical evidence of significant medical illness in any patient. Specifically excluded were cardiovascular disease and blood dyscrasias. All adults underwent preoperative screening, including physical examination, chest x-ray, electrocardiogram, routine blood chemistries, and complete blood count and urinalysis.

We observed evidence of ischemia in only one of the eyes under study (#261. This case was quite mild and there was no resulting visual loss.

Case Report

A 32-year-old woman suffered bilateral sixth nerve palsies as a result of head trauma in an automobile accident. On examination eight months following the injury, abduction of the left eye had improved to 30 degrees beyond the midline. The right eye remained in extreme adduction. Recessions of both medial recti were performed. Because of a residual abduction deficit, full tendon lateral transpositions of the vertical recti in the right eye were performed two months following the initial procedure. On examination, one week after gurgery, there was no unusual discomfort, but the visual acuity in the right eye was 20/30. An ovoid pupil with temporal iris alruphy, minimal eeH and flare, and early cortical lens vacuoles were noted !Figure II. lbpical steroid, cycloplegic and antibiotics drops were prescribed, and the inflammation resolved over a three- week course. The visual acuity returned to 20/20, though mild iris atrophy and peripheral lens vacuoles remain.

Discussion

ASI represents a generally recognized and dreaded complication of rectus muscle surgery.1'6 Although there have been a number of case reports, the incidence of ASI following extensive muscle surgery is unknown. Affected patients typically underwent procedures to correct paralytic strabismus or combined horizontal and vertical misalignments. Muscle transposition surgery has been especially prone to provoke ASI. 1^-3

Table

TABLE 1EYES WITH SURGERY ON THREE RECTUS MUSCLES

TABLE 1

EYES WITH SURGERY ON THREE RECTUS MUSCLES

Table

TABLE 1EYES WITH SURGERY ON THREE RECTUS MUSCLES

TABLE 1

EYES WITH SURGERY ON THREE RECTUS MUSCLES

Table

TABLE 2EYES WITH SURGERY ON FOUR RECTUS MUSCLES

TABLE 2

EYES WITH SURGERY ON FOUR RECTUS MUSCLES

Table

TABLE 3EYES WITH SURGERY ON TWO OR THREE RECTUS MUSCLES IN PATIENTS WITH THYROID DISEASE

TABLE 3

EYES WITH SURGERY ON TWO OR THREE RECTUS MUSCLES IN PATIENTS WITH THYROID DISEASE

Advocates of stepwise surgery assume that the interval between procedures should permit re-establishment of the anterior ciliary circulation through the operated muscles.2.12·13 Hayreh and Scott reported persistent segmental filh'ng defects on iris angiography after tenotomy of the vertical recti. They found that revascularization does not occur for at least six months and that the major arterial circle of the iris does not furnish significant collateral flow to the anterior segment.6 Saunders and Sandall suggest that four muscles should never be detached from one eye irrespective of the interval between surgeries.1

In our series of eyes with surgery on three or four rectus muscles, all but two had an interval of two months or longer before detachment of the third or fourth muscles. Within this group of otherwise healthy individuals, we found evidence of clinically significant ASl in only one patient, who suffered no visual consequences. We do recognize that three- or four-muscle surgery may occasionally lead to more serious complication, especially in the presence of concurrent cardiovascular or hématologie disease. Adults are at greatest risk. To our knowledge, ASI has never been reported in a child following strabismus surgery. Certainly, it is best to use stepwise surgery involving the minimum possible number of muscles and to explain all potential complications preoperatively. We feel that the risk of ischemia in healthy patients is low enough that a third or fourth reclus muscle may be safely detached following an interval of several months.

FIGURE: (Simon et al.). Clinical photograph showing ovoid pupil and temporal iris atrophy following surgery on the third and fourth rectus muscles of this 32-year-old woman's right eye (case #26). Visual acuity returned to 20/20 following topical steroid therapy. (Photograph provided by Dr. John FlynnJ

FIGURE: (Simon et al.). Clinical photograph showing ovoid pupil and temporal iris atrophy following surgery on the third and fourth rectus muscles of this 32-year-old woman's right eye (case #26). Visual acuity returned to 20/20 following topical steroid therapy. (Photograph provided by Dr. John FlynnJ

Fells and Marsh suggest that thyroid patients have an increased risk of ASI following two-muscle surgery for thyroid ophthalmopathy.R None of our seven cases of thyroid ophthalmopathy (four with two-muscle surgery and three with three-muscle surgery) developed any ischemie complications postoperatively. Our experience suggests to us that the risk of ASI in thyroid patients is low enough to justify removing two muscles at one time, and perhaps a third muscle from the same eye at a later date.

The relative contributions of the two long posterior and anterior ciliary arteries in supplying the anterior segment has not yet been clearly defined. Recent experimental evidence indicates that these circulations remain separate, without collateral izatio n in the major arterial circle.7 Reports of ASI following scierai buckling procedures with reclus muscle detachmenl may have been partially provoked by the compressive effect of encircling elements on the posterior circulation.2·9-11·15 Both patients reported by Saunders and Sandall suffered from compromised circulatory function preoperatively: one had undergone ipsilateral carotid artery ligation, and the other had type II hype rl ipoproteinemia . l

Several of the eyes in this study underwent uneventful surgery on all four rectus muscles within a two-month period, and the authors are aware of at least one case in which simultaneous t r anse étions of all four rectus muscles was tolerated by a healthy child. It may be that re-establishment of the anterior ciliary circulation occurred promptly in our patients, or that the posterior circulation alone was able to sustain adequate blood flow to the anterior segment.

Acknowledgment

The clinical photograph and follow-up information in Case 26 were provided by Dr. John Flynn.

References

1. Saundera RA, Sandall GS: Anterior segment ischemia syndrome following rectua muscle transposition. Am J Ophthalmol 1982; 93:34-38.

2. Girard LJ, Beltranena F: Early and late complications of extensive muscle surgery. Arch Ophthalmol 1960; 64:576-584.

3. McNeer KW: Three complications of strabismus surgery. Ann Ophthalmol 1975; 7:441-446.

4. Helveston EM: How many muscles? Ophthalmol Dig 1975; 37:13-15.

5. Hiatt RL: Production of anterior segment ischemia. J Pediatr Ophthalmol Strabismus 1978; 15:197-204.

6. Hayreh SS, Scott WE: Fluorescein iris angiography. II. Disturbances in iris circulation following strabismus operation on the various recti. Arch Ophthalmol 1978; 96:1390-1400.

7. Woodlief NF: Initial observations on the ocular microcirculation in man. J. The anterior segment end est raocular m úseles. Arch Ophthalmol 1980; 98:1268-1272.

8. Fells P, Marsh RJ: Anterior segment ischaemia following surgery on two rectus muscles, in Reinecke RD tedi: Strabismus. Proceedings of the Third Meeting of the International Strabismological Association. New York, Gruñe & Stratton Inc. 1978, pp 375-380.

9. Jacobs DS, Vestine DW, Urist MJ: Anterior segment ischemia and sector iris atrophy. After strabismus surgery in a patient with chronic lymphocytic leukemia. Ophthalmic Surg 1976; 7:42-48.

10. Ryan SJ, Goldberg MF: Anterior segment ischemia following scierai buckling in sickle cell hemoglobinopathy. Am J Ophthalmol 1971; 72:35-50.

11. Eagle RC, Yanoff M, Morse PH: Anterior segment necrosis following scierai buckling in hemoglobin SC disease. Am J Ophthalmol 1973; 75:426-433.

12. Krewson WE III: Ocular tendon transplantation. Indications, variations and technic. J Int Coll Surgeons 1957; 27:731-737.

13. Fiarley RD: Complete tendon transplantation for ocular muscle paralysis. Ann Ophthalmol 1971; 3:459-463.

14. Callahan MA: Surgically mismanaged ptosis associated with double elevator palsy. Arch Ophthalmol 1981; 99:108-112.

15. Boniuk M, Zimmerman LE: Necrosis of the iris, ciliary body, lens, and retina following scierai buckling operations with circling polyethylene tubes. Trans Am Acad Qphtkalmal Otolaryng 1961; 65:671-691.

TABLE 1

EYES WITH SURGERY ON THREE RECTUS MUSCLES

TABLE 1

EYES WITH SURGERY ON THREE RECTUS MUSCLES

TABLE 2

EYES WITH SURGERY ON FOUR RECTUS MUSCLES

TABLE 3

EYES WITH SURGERY ON TWO OR THREE RECTUS MUSCLES IN PATIENTS WITH THYROID DISEASE

10.3928/0191-3913-19840901-06

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