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Article Date: 9/1/2012

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Giant Retinal Tears After Pars Plana Vitrectomy for Diabetic Vitreous Hemorrhage
CASE STUDY

Giant Retinal Tears After Pars Plana Vitrectomy for Diabetic Vitreous Hemorrhage

A result of excessive vitreous base shaving?

Daniel L. Chao, MD, PhD • Marco Gonzalez, MD • Harry W. Flynn, JR, MD

Giant retinal tears (GRTs) are defined as retinal tears greater than three contiguous clock hours. A majority of GRTs have an idiopathic etiology, while the remaining GRTs are due to blunt or iatrogenic trauma.1-3 In the current report, two cases of giant retinal tears with retinal detachment after pars plana vitrectomy are described in patients with vitreous hemorrhage (VH) from proliferative diabetic retinopathy (PDR).

CASE 1

A 41-year-old Latino man with a history of type 1 diabetes mellitus and PDR in both eyes presented seeing dark shadows in the OD for one month. His past ocular history included panretinal photocoagulation and focal laser in both eyes for PDR.

Because of persistent dense vitreous hemorrhage, he underwent pars plana vitrectomy OD two years earlier at an outside medical center. His best-corrected visual acuity on initial examination was 20/25 in both eyes. A giant retinal tear was noted from 8 o'clock to 12 o'clock in the peripheral retina of the right eye (Figure 1).

Figure 1. A 41-year-old man with a history of PDR and PPV two years earlier presented with a giant retinal tear in the right eye. The giant retinal tear was rolled up and contracted and extended from 8 o'clock to 12 o'clock, demarcated posteriorly by extensive PRP. The macula was attached and stable with 20/25 visual acuity.

The giant retinal tear was well demarcated by the previous PRP and spared the macula. The foveal contour was normal on OCT. The patient has been observed for the past one-and-a-half years, and the associated retinal detachment has not progressed.

Daniel L. Chao, MD, PhD, is a second-year resident in ophthalmology at the Bascom Palmer Eye Institute in Miami, Fl. Marco Gonzalez, MD, is a third-year resident in ophthalmology at Bascom Palmer. Harry W. Flynn, Jr., MD, is professor and J. Donald M. Gass Distinguished Chair of Ophthalmology at Bascom Palmer. This research was supported by NIH Center Core Grant P30EY014801, a Research to Prevent Blindness Unrestricted Grant, and the U.S. Department of Defense (DOD Grant#W81XWH-09-1-0675). Dr. Flynn can be reached via e-mail at hflynn@med.miami.edu.

CASE 2

A 53-year-old man from Trinidad with a history of type 1 diabetes and severe PDR was examined because of a dense VH in the left eye. He returned with a giant retinal tear OS five months after he underwent 25-gauge PPV, membrane peeling, endolaser, and fluid-air exchange for nonclearing vitreous hemorrhage. The giant tear and RD spared the macula and were demarcated by previous PRP (Figure 2).

Figure 2. A 53-year-old man with PDR and a history of PPV for nonclearing vitreous hemorrhage presented with a giant retinal tear visible from 12:30 to 3:30. The macula was attached. The associated retinal detachment extended both nasally and temporally.

The patient subsequently underwent 25-g PPV with endolaser, air-fluid exchange, scleral buckle, and silicone oil injection and had successful reattachment. The patient subsequently had silicone oil removal one year later, and the retina has remained attached over seven years of follow-up (Figure 3). His vision had improved to 20/80 OS at the last follow-up in 2012.

Figure 3. Postoperative photo of case 2 after RD repair using PPV with silicone oil. The retina was attached, and the silicone oil was removed one year later. Visual acuity remained 20/80 after retinal reattachment surgery.

DISCUSSION

Giant retinal tears and associated RDs are rare complications of pars plana vitrectomy. The precise mechanism of giant retinal tears in this setting following vitrectomy is uncertain. Etiologies include intraoperative breaks and traction on the adjacent vitreous base near the sclerotomy sites, postoperative fibrovascular tissue ingrowth at the pars plana wound sites,3 and vitreous gel incarceration due to multiple pars plana entries.4-5

One recent prospective, single-center study reported a 15% retinal break rate after PPV, but there was only a 3% rate related to sclerotomy sites.6 In this report, there was no statistically significant difference in breaks between 23- and 25-g vitrectomies.6

In these two patients, no retinal breaks were identified at the time of surgery, but residual blood in the vitreous base may have blocked a view of intraoperative breaks.

A giant retinal tear was also reported after pneumatic retinopexy, thought to be due to pre-existing posterior vitreous detachment and migration of intraocular gas into the retrohyaloid space, causing vitreoretinal traction.7

Pars plana vitrectomy for PDR is not usually considered to be a risk factor for giant retinal tears.2 One possibility is that excessive shaving of the vitreous base during PPV may lead to large or multiple intraoperative breaks, which may be obscured by the dense peripheral vitreous hemorrhage.

In case 1, the previously placed extensive PRP for PDR served as a demarcation barrier to protect against progression into the macula and to allow for stable visual acuity over a two-year period. In the second case, due to the progression and the severity of the tear, surgical repair of the retinal detachment was performed.

Surgical repair of giant retinal tears can be challenging due to the high rate of PVR and high redetachment rates. Usual surgical approaches include vitrectomy with combined perfluorocarbon liquid, laser, and injection of either gas or silicone oil, as well as the use of scleral buckling surgery in selected cases.8

For the two patients in this current report, each had a favorable clinical course in the face of a serious postoperative complication. RP

REFERENCES

1. Kanski JJ. Giant retinal tears. Am J Ophthalmol. 1975;79:846-852.
2. Ang GS, Townend J, Lois N. Epidemiology of giant retinal tears in the United Kingdom: the British Giant Retinal Tear Epidemiology Eye Study (BGEES). Invest Ophthalmol Vis Sci. 2010;51:4781-4787.
3. Abu el-Asrar AM. Giant retinal tears after pars plana vitrectomy. Eye (Lond). 1997;11:325-327.
4. McLeod D. Giant retinal tears after central vitrectomy. Br J Ophthalmol. 1985;69:96-98.
5. Kreiger AE. Wound complications in pars plana vitrectomy. Retina. 1993; 13:335-344.
6. Ehrlich R, Goh YW, Ahmad N, Polkinghorne P. Retinal breaks in small-gauge pars plana vitrectomy. Am J Ophthalmol. 2012;153:868-872.
7. Yam JC, Liu DT, Lee VY, Lam PT, Lam DS. Giant retinal tear after pneumatic retinopexy. Acta Ophthalmol. 2008;86:232-233.
8. Ghosh YK, Banerjee S, Savant V, et al. Surgical treatment and outcome of patients with giant retinal tears. Eye (Lond). 2004;18:996-1000.



Retinal Physician, Volume: 9 , Issue: September 2012, page(s): 40 41

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