EXTRABULBAR TISSUE PROLAPSE

The primary objective in managing injured eyes is to reestablish the original anatomy and function.1,2 Proper handling of prolapsed tissues is essential to

achieving a good outcome.3 In this chapter we provide guidelines regarding the indications and techniques of treating tissue prolapse, a common finding in open globe trauma. The incidence of tissue prolapse is:

•42% (USEIR) to 45% (México City, 1991a) in open globe injuries; and

•significantly higher in ruptures (70%) than in lacerations (49%; USEIR).

DEFINITION AND HISTORY

suture and left to heal. Scleral wounds were treated similarly, with no intent of closure by sutures. Leeches were recommended to deal with the “congested uvea” associated with trauma.4 It was accepted that wounds involving the retina or choroid would be followed by retinal detachment and phthisis.4 Enucleation was routinely performed in cases of prolapsed ciliary body, choroid, retina, or vitreous.5,6 The vitreous was thought to hold the retina in place; consequently, its removal was prohibited.5 Even when wounds finally began to be sutured, corneal scarring and retinal detachment commonly resulted in poor visual results, which started improving only after the 1950s, with the advent of microsurgery, antibiotics, and steroids. The functional outcomes still leave room for improvement.5,7–9

Tissue prolapse is defined as extrusion of intraocular content outside its normal compartment, whether intrabulbar (e.g., vitreous in the AC) or extrabulbar (e.g., expulsed lens).

Before the early 20th century, iris prolapseb through a corneal wound was considered a severe complication because of:

•fear of infection;

•fear of SO; and

•technical difficulties in management.

When topical eserine and bright light were not sufficient to return the iris to the AC, the wound was simply covered by a conjunctival flap with a purse-string

PATHOPHYSIOLOGY

Tissue extruded in the context of open globe injury is usually perceived as:

•a condition complicating the initial repair; and

•a risk factor for a less favorable anatomical/visual outcome.

With the formation of a full-thickness wound, the globe’s sudden decompression may force the iris/ choroid/vitreous/retina into the wound. Because of their inside-out mechanism (see Chapter 1), ruptures have a worse prognosis than lacerations: due to the increased IOP,10–12 tissue loss is not only more common but also more severe.8,13 Other acute and chronic aggravating factors include:

aUnpublished data of the author.

bEspecially if older than 24–48 hours.

•orbital and intraocular bleeding/inflammation/ injection;

•lens swelling; and

•excessive manipulations during evaluation (Fig. 16–1).

PEARL... Tissue incarceration eventually plugs the wound, reestablishes the IOP, and tamponades the bleeding, helping to

preserve the eye’s anatomy.11

The trapped prolapsed tissue is subsequently secured by fibrin formation within a few hours and fibrosis within a few days1,14 (Fig. 16–2). This may lead to:

•inadequate wound healing;

•leakage of aqueous;

•hypotension;

•endophthalmitis;

•epithelial ingrowth;

•chronic inflammation;

•corneal decompensation;

•dense, vascularized corneal scars;

•synechia formation;

•CME1,15; and

•retinal detachment.

PEARL... Intraocular tissue prolapse should be suspected in all open globe injuries. Remember that the wound may remain

hidden (e.g., occult rupture).

Unless the wound is posterior and underneath a congested, edematous conjunctiva or blood-stained Tenon’s capsule (see Chapters 13 and 15), the tissue prolapse is usually visible upon careful inspection. The clinician should look for the following signs:

FIGURE 16–2 Photomicrograph. Uveal tissue incarcerated in scleral wound prevents adequate wound apposition and healing. (Courtesy of Dr. Alfredo Gomez-Leal, Asocoación para Evitar la Ceguera en México.)

•vitreous traction strands (best seen in the retrolental space at the slit lamp);

•vitreous hemorrhage; and

•low IOP.

P I T F A L L

Tissue prolapse may occur during transportation or be due to poor patient instruction and restriction and/or lack of eye shielding. As soon as an open globe injury is suspected, further diagnostic manipulations should be kept to a minimum (see Chapter 8).

Preoperative echography and CT scan may show tissue prolapse in case of a posterior scleral break. Although these techniques are seldom necessary when deciding whether to explore the globe, they may aid in planning the surgery.16,17

MANAGEMENT

Heavy topical and systemic corticosteroid therapy is essential to minimize inflammation (see Chapter 8). The rules of culturing and antibiotic therapy10,18 follow the general principles for open globe trauma (see Chapter 28 and the Appendix). The implications, instrumentation, and technique of management vary with each tissue (see below and Fig. 16–3). All tissue prolapses should be addressed at the time of wound repair (Fig. 16–4).

FIGURE 16–4 Iris prolapse through limbal wound.

P I T F A L L

Leaving tissue prolapsed may lead to severe complications such as SO and is acceptable only if severe bleeding occurs (ECH/SCH; see Chapter 22).

Irisc (see also Chapter 18)

Conventional wisdom dictated that iris exposed for more than 24 hours should be excised for fear of introducing infected material or epithelial cells into the eye.2,10,19 With improved surgical techniques, technology, and pharmaceuticals, the surgeon should not be dogmatic about this 24-hour deadline.15

PEARL... The pupillary margin is more susceptible to ischemia than the

root of the iris.

Excisiond is recommended for:

•necrotic;

•nonviable (macerated, depigmented, feathery); or

•severely contaminated iris.

If excision is required, maximal iris preservation is the goal for cosmesis and to minimize glare by pre-

cThe other parts of the uvea (i.e., ciliary body and uvea) are virtually never excised.

dWhen excising iris tissue incarcerated in wound, remember that more iris is drawn from the central iris than from the root area.

serving pupillary function. Traction should be minimized and suturing of the defect is recommended (see Chapter 18).

The removed material can be cultured. Epithelial cells can usually be removed by mechanical (abrasion), chemical (alcohol), or thermal (cryotherapy) means.

Reposit the prolapsed iris if it is:

•viable;

•free from epithelial overgrowth; and

•free from bacterial contamination

Prior antibiotic irrigation may prevent endophthalmitis. The repositioning technique varies by the extent, location, and duration of the prolapse. Approaching the commonly atonic and floppy, difficult- to-manipulate2 iris at the original wound seldom works and may cause further damage to the iris and/or cornea. Usually, one or a combination of the following is attempted:

•gentle sweeping/pulling with a spatula through a limbal paracentesis;

•viscoelastics;

•miotics20 (if the peripheral iris is entrapped);

•mydriatics10 (if the central iris is involved); and

•in a more chronic injury with the iris “glued” to the wound edges by fibrin, careful dissection using fine, atraumatic forceps.

PEARL... Repositioning the iris is easier by pulling than by pushing.

Whether the iris is incised or repositioned, it is crucial to prevent postoperative synechia formation by using pharmacological agents, air, or viscoelastics.

Prolapse of the ciliary body and the choroid is much less common. As mentioned, they are rarely excised for fear of bleeding, inflammation with cyclitic membrane formation, and phthisis. They are usually reposited using the zipper technique, gently pushing/ holding the uveal tissue back with a spatula while the sutures are placed.

Postoperatively, aggressive anti-inflammatory therapy is recommended. Any secondary anterior segment reconstruction is usually performed after a few months.2

Lens

No intervention is needed if the lens is completely lost. Subconjunctival lens/remnants require removal. Rarely, lens particles may be entrapped in the wound.

These must be removed; simultaneous vitreous prolapse is common (see Chapter 21).

Vitreous

Poor management of prolapsed vitreous is a rather common and avoidable source of late complications such as:

•corneal decompensation;

•chronic inflammation;

•CME;

•tractional retinal detachment; and

•phthisis.9,19

PEARL... Vitreous prolapse is not simply the target of a surgical manipulation: by doubling the risk of retinal detachment

development in case of open globe injury (30% vs. 14%, USEIR), it has prognostic significance.

The incidence of retinal detachment is higher with wounds at the ora serrata than at the equator (78% vs. 16%), due to the involvement of the vitreous base.21

Removal of the prolapsed vitreous:

•permits orderly wound healing;

•gets rid of the matrix for fibrous ingrowth and/or proliferation22;

•prevents traction on the vitreous base and retina1; and thus

•prevents the formation of retinal breaks and detachment.

PEARL... Damage to the zonules must have occurred if vitreous prolapses into the AC.e Retinal injury exists if vitreous pro-

lapse occurs through a scleral wound posterior to the insertion of extraocular muscles.11

Retinal breaks, including giant tears, are most commonly found either just posterior to the scleral wound or 180° away, and are caused by direct traction (Fig. 16–5).

PEARL... The vitreous responsible for complications is not what has been

removed but what remains behind.11

e Rare exception: vitreous prolapse through an in situ lens.

FIGURE 16–5 Vitreous prolapse often leads to traction and retinal tears, either in the vicinity of the prolapse (arrow) or 180° away (double arrow).

Vitreous prolapsed into the AC or into the lens must be removed. Several techniques increase the chance of recognizing that there are vitreous remnants in the AC19:

•air;

•viscoelastics (less effective than air; see Chapter 17);

•miotics;

•tangential light shone externally with the endoilluminator from the limbus; and

•pupillary deformation caused by vitreous strands.

To minimize traction, the vitrectomy probe is preferred to cellulose sponges and scissors for removing vitreous from the wound. This is especially crucial when the wound is scleral and the expulsed vitreous is mixed with blood.

PEARL... Vitreous gel may remain attached to the interior aspect of the wound, especially over the sclera. The surgeon must attempt to remove it as completely as is consistent with safety, without causing globe col-

lapse or retinal injury.

The vitreous may be incarcerated in the posterior exit wound of a perforating injury (Fig. 16–6). These rapidly self-sealing wounds usually do not permit external tissue excision. The surgeon may be forced

to limit the intervention to internal trimming of the trapped vitreous (see Chapter 26).

P I T F A L L

Too early intervention for posterior vitreous prolapse may result in wound reopening with disastrous consequences.

Vitreous prolapse often leads to retinal traction along the vitreous base.22 Prophylactic encircling bands are nevertheless controversial. We prefer their use if:

•the wound involves an area near the vitreous base;

•vitreous removal is suboptimal; and

•secondary reconstruction is unlikely to be performed (e.g., systemic reasons, poor patient compliance9).

Retina

Of all prolapses, that of the retina has by far the poorest prognosis.

PEARL... Proper management of incarcerated vitreous is of utmost importance to prevent retinal entrapment in the

wound and subsequent retinal detachment.

Retinal extrusion usually occurs in cases of large posterior ruptures, commonly associated with severe ECH. Vitreous is almost always present and its loss often substantial (Fig. 16–7).

If possible, the retina should be gently pushed back into the eye, using viscoelastics if necessary (see Chapter 5, Fig. 5–2). The wound should then be sutured and the retinal lesion and the injury’s consequences dealt with during a second procedure.

Subsequent fibrous ingrowth may entrap the retina if it is caught in between the lips of the scleral wound. Typically, retinal detachment with folds radiating from the incarceration site develops within weeks. In more severe cases, the whole anterior aspect of the retina is drawn to the wound. Echography is useful in case of media opacity. Because these detachments are difficult to treat1 and the PVR23 rate is high, prophylaxis of retinal incarceration is preferred by excising all extruded vitreous, gently pushing the retina back and using the zipper technique to close the wound.

P I T F A L L

Because it increases inflammation and stimulates PVR development, it is best to avoid prophylactic cryotherapy of the scleral wound.24,25

If retinal incarceration occurs, secondary reconstruction must almost always be performed,7 typically involving a scleral buckle7 and vitrectomy. We perform it 10 to 14 days after the injury, when inflammation is under control and the intraocular anatomic status has been assessed adequately. A wide-angle viewing system is invaluable to optimize the surgical tactics when the vitreous hemorrhage and residual vitreous have been removed (see Chapter 8).

•Small anterior retinal entrapments may be left without excision if supported by a scleral buckle, but the risk of secondary detachment is high.

•Larger and posterior folds may require both buckles15 and retinotomy.26

•If the incarceration is near the equator, an exoplant may be added to relieve the traction.7,23

•If retinotomy is necessary, the surgeon’s initial instinct is to minimize the size of the resulting retinal defect, but “small” is usually less effective than “large.” Enough space should be left between the freed retinal edge and the remaining scar tissue to prevent a secondary retinal detachment.

PEARL...

to be larger than originally anticipated.

•The retinotomy should be performed only after the vitreous, including the posterior hyaloid, and all proliferative tissues have been removed.

•The retina is cauterized and cut by scissors, rather than by the vitrectomy probe,26 to increase accuracy.

•Removal of the peripheral retina in cases of anterior incarceration is important to prevent subsequent neovascular proliferation.

REFERENCES

•Subretinal membranes can be extracted through the same retinotomy. Use of PFCL helps keep the retina stable while these maneuvers are performed.

•Although long-acting gases may also be used for tamponade, silicone oil is usually preferred if large retinotomies are required.27

Vitrectomy has improved the anatomic success rates in the past 30 years (from 5213 to 73%7), but the visual outcome in eyes with retinal prolapse/incarceration is still disappointing: only 40% achieve 75 2007 vision because of severe PVR and macular damage at the time of the original injury.

SUMMARY

Proper management of all tissue prolapses is essential to achieve good visual and anatomic results in the traumatized eye. The preservation of as much viable and noninfected uveal tissue as possible is important. Although the surgeon performing the initial repair is commonly required to remove prolapsed tissue from the wound, this procedure has received surprisingly little attention in the literature. Observation of the rules outlined here should help reduce complications, whether caused by the injury or inflicted by inadequate tissue handling.

1.Conway BP, Michels RG. Vitrectomy techniques in the management of selected penetrating ocular injuries. Ophthalmology. 1978;85:560–583.

2.Colby K. Management of open globe injuries. Int Ophthalmol Clin. 1999;39:59–69.

3.Brinton GS, Aaberg TM, Reeser FH, et al. Surgical results in ocular trauma involving the posterior segment. Am J Ophthalmol. 1982;93:271–278.

4.Ramsey AM. Eye Injuries and Their Treatment. Glasgow: Maclehose; 1907:65–69.

5.Callahan A. Surgery of the Eye: Injuries. Springfield, IL: Charles C Thomas; 1950.

6.Spaeth EB. Principles and Practice of Ophthalmic Surgery. 4th ed. Philadelphia: Lea & Febiger; 1948.

7.Han DP, Mieler WF, Abrams GW, et al. Vitrectomy for traumatic retinal incarceration. Arch Ophthalmol. 1988;106:640–645.

8.Russel SR, Olsen KR, Folk JC. Predictors of scleral rupture and the role of vitrectomy in severe blunt ocular trauma. Am J Ophthalmol. 1988;105:253–257.

9.Ahmadieh H, Soheilian M, Sajjiadi H, et al. Vitrectomy in ocular trauma. Factors influencing final visual outcome. Retina. 1993;13:107–113.

10.Navon SE. Management of the ruptured globe. Int Ophthalmol Clin. 1995;35:71–91.

11.Kuhn F, Mester V. Anterior open globe injuries with vitreous prolapse and/or incarceration. In: Stirpe M, ed. Anterior and Posterior Segment Surgery: Mutual Problems and Common Interests. New York: Ophthalmic Communications Society; 1998:252–257.

12.Freitag SK, Eagle RC, Jaeger EA, et al. An epidemiologic and pathologic study of globes enucleated following trauma. Ophthalmic Surg. 1992;23:409–413.

13.Meredith TA, Gordon PA. Pars plana vitrectomy for severe penetrating injury with posterior segment involvement. Am J Ophthalmol. 1987;103:549–554.

14.Winthrop SR, Cleary PE, Minckler DS, Ryan SJ. Penetrating eye injuries: a histopathological review. Br J Ophthalmol. 1980;64:809–817.

15.Orlin SE, Farber MG, Brucker AJ, et al. The unexpected guest: problem of iris reposition. Surv Ophthalmol. 1990;35:59–66.

16.Benjamin L, Wormald R. CT scan diagnosis of scleral rupture. Eye. 1987;1:757.

17.Coleman DJ, Jack RL, Franzen LA. Ultrasonography in ocular trauma. Am J Ophthalmol. 1973;75:279–288.

18.Rubsamen PE, Cousins SW, Martinez JA. Impact of cultures on the management decisions following surgical repair of penetrating ocular trauma. Ophthalmic Surg Lasers. 1997;28:43–49.

19.Hudson HL, Thomas EL, Novack RL, et al. Primary surgical management of penetrating eye injuries. In: Alfaro DV, Liggett PE. Vitreoretinal Surgery of the Injured Eye. Philadelphia: Lippincott-Raven; 1998: 71–85.

20.Getnick RA, Peterson WS. Pharmacologically assisted repair of iris prolapse. Ophthalmic Surg. 1995;29:89.

21.Hsu HT, Ryan SJ. Experimental retinal detachment in the rabbit. Retina. 1986;6:66–69.

22.Cleary PE, Ryan SJ. Method of production and natural history of the experimental posterior penetrating eye injury in the rhesus monkey. Am J Ophthalmol. 1979; 88:212–220.

23.Michels RG, Thompson JT, Rice TA, et al. Effect of scleral buckling on vector forces caused by epiretinal membranes. Am J Ophthalmol. 1986;102:449–451.

24.Campochiaro PA, Gaskin HC, Vinores SA. Retinal cryopexy stimulates traction retinal detachment formation in the presence of an ocular wound. Arch Ophthalmol. 1987;105:1567–1570.

25.Jaccoma EH, Conway BP, Campochiaro PA. Cryotherapy causes extensive breakdown of the blood-retinal barrier. Arch Ophthalmol. 1985;103:1728–1730.

26.Machemer R, McCuen BW, de Juan E. Relaxing retinotomies and retinectomies. Am J Ophthalmol. 1986;102: 7–12.

27.Liggett PE, Mani N, Green RE, et al. management of traumatic rupture of the globe in aphakic patients. Retina Suppl. 1990;10:S59–S64.