Dr. SANGEET MITTAL

Dr.Jaswant Singh Thind

Abstract

Chorioretinectomy is a relatively new procedure for deep impact ocular trauma resulting in vitreous incarceration or penetration of choroid. It can be done either for a prophylactic or a therapeutic purpose. It prevents PVR, fibrous ingrowth and epiretinal membrane formation at the site of incarceration. The procedure consists of vitrectomy with or without base shaving, 100% deep diathermy burns around incarceration site, removal of incarcerated retinal tissue and the underlying choroid and 1-2 rows of laser around the chorio-retinectomy. The aim of the paper is to present different cases who were managed using the above technique.

Full Text

Introduction: Chorio-retinectomy is a relatively new procedure for deep impact ocular trauma resulting in vitreous incarceration or penetration of choroid. In 1987, Dr Zivojnovic¹ described a surgical technique of removing incarcerated retina and scar tissue within a perforation site. Kuhn et al² later published a surgical procedure called a prophylactic chorio-retinectomy to treat perforating globe within 100 h of injury. It can be done either for a prophylactic or a therapeutic purpose. It prevents proliferative vitreoretinopathy (PVR), fibrous ingrowth and epiretinal membrane formation at the site of incarceration. The procedure consists of vitrectomy with or without base shaving, 100% deep diathermy burns around incarceration site, removal of incarcerated retinal tissue and the underlying choroid and 1-2 rows of laser around the chorio-retinectomy. The aim of the paper is to present different cases who were managed using the above technique.

Methods: This is a retrospective analysis of 11 eyes of penetrating eye injury with or without intraocular foreign body (March 2018 to March 2020) in whom vitreous was incarcerated in posterior retina. All eyes had visual acuity greater than or equal to accurate projection of rays. The period between primary repair and vitrectomy was noted for all cases. All eyes underwent 25/27 gauge Pars Plana Vitrectomy (PPV) using a non-contact widefield viewing system. After completing vitreous base shaving and peripheral retinal examination for retinal tears, chorio-retinectomy was performed. A chorio-retinectomy in this study was defined as the removal of incarcerated retinal tissue with underlying choroid to the level of bare sclera 360° around the impact or perforating site of a foreign body using the 25/27-gauge vitreous cutter. Before chorio-retinectomy, deep endodiathermy was applied to the surrounding retina pigment epithelium and choroid that is going to be cut. This technique removed any remaining RPE exposed to the vitreous cavity. Intraocular bleeding was controlled by using endodiathermy and/or transiently raising the infusion bottle. 1-2 rows of laser was done around the chorio-retinectomy site. Perfluoropropane gas or silicon oil tamponade was done as needed.

Results: All patients included in the study were males. The average age was 28.3±12.06 years. In 7 out of 11 eyes, the foreign body was intraocular and impacted in the posterior wall of globe. In 2 eyes, there was an exit wound through which the foreign body had pierced causing a double perforation. In 1 eye, the trauma was due to a knife injury and in 1 eye it was due to cow’s horn. 4 eyes had associated retinal detachment whereas 1 eye had associated endophthalmitis. Silicon oil tamponade was done in 5/11(45.5%) eyes. Visual improvement after surgery was seen in 10/11 (90.9%) eyes. Recurrent PVR occurred in 2/11 (18.2%) eyes. Retina was attached in all eyes at last follow up.

Discussion: Many studies have been published for the ideal treatment of perforating/penetrating posterior segment injuries with or without a retained IOFB. In the non-chorio-retinectomy technique, the PVR rate is between 62-89%. Pathologic findings have disclosed that PVR is the result of RPE proliferation and fibrous proliferation from the wound. During chorio-retinectomy eliminates all the exposed RPE following a foreign body injury, as well as the fibrous proliferation around the perforation/impact site. The theoretic advantage of this technique is to remove any hemorrhage and inflammatory components with PPV, and to prevent fibrous adhesions from the retina to the impact or perforation site. Additional benefits of chorio-retinectomy include removal of incarcerated vitreous and or retina into the perforation site, the removal of retained foreign body fragments in the choroid or sclera, and removal of fibroproliferative tissue at the choroid/sclera interface. The PVR rates in perforating eye injuries decreased after chorio-retinectomy techniques.

Our PVR rates were lower (18.2% vs 62%) when compared with earlier studies. All these differences may be explained by the nature of the injury; almost all of our cases were caused by intra-ocular foreign bodies, whereas most of the patients in earlier studies were wounded by conventional and unconventional fragmentary munitions.

The timing for this surgery is also controversial. Kuhn et al suggest surgery within 100 h of the injury; however, the surgery in this period is technically very difficult with lots of hemorrhage during surgery and leakage from the impact and exit wounds. We feel that early chorio-retinectomy within a week (5–7 days) can still prevent PVR related to exit/IOFB impact site and also allows removal of intravitreal blood and disconnection of the intravitreal wound tract with less leakage, hemorrhage, and corneal problems. On the other hand, some of the authors still suggest late surgery, which is 2 weeks after the injury, which gives the advantage of performing the surgery in a quite eye mostly with posterior hyaloidal detachment and without any new haemorrhage and leakage. The cornea also becomes clearer within that period. However, PVR is the main problem in those eyes and retinal detachment is very frequent at that period. The mean period between primary repair and vitreoretinal surgery was 2 weeks in our cases, the earliest being within 2 days and latest being 40 days. We advocate performing surgery at the end of first week, which averages the advantages and disadvantages of early vs late surgery.

In our study group, final BCVA ranged from 20/20 to CF from 50 cm. Kuhn et al²¹ reported in 2006 that 64% of all perforating trauma and 25% of IOFB injuries had a BCVA worse than 20/200. On the other hand, in these severe globe injuries, it is obvious that even the chorio-retinectomy surgical technique may fail, and eventually lead to phthisis.

Anatomical success of this extensive chorio-retinectomy technique in our study group seems to be better(100% globe survival and 84.6% final reattachment rate). It is obvious that visual acuity stabilization after posterior segment ocular trauma may take many years. But we believe that there are other reasons for these comparatively lower final BCVA results. The main reason for the lower visual results is that 10 of 13 patients (77%) had macular injury. Performing chorio-retinectomy in cases with macular injury is a controversial issue. However, we believe that chorio-retinectomy should be performed even in cases with macular impact site to augment retinal attachment and globe survival. Another problem limiting the final vision is the presence of corneal scarring. Of 13 patients, 9 (69.2%) had entry site involving cornea resulting in a corneal scar in our series, but none of these patients had penetrating keratoplasty yet limiting the final BCVA.

In conclusion, chorio-retinectomy in perforating eye injuries seems to prevent exit site wound-related PVR in most of the cases when performed as early as possible.

References:

1. Zivojnovic R. Silicone Oil in Vitreoretinal Surgery. Marinus Nijhoff: Dordrecht, The Netherlands; 1987. pp. 45–103.
2. Kuhn F, Mester V, Morris R. A proactive treatment approach for eyes with perforating injury. Klin Monat Augen. 2004;221:8:622–628