Modified transscleral external drainage of subretinal fluid in high bullous exudative retinal detachment due to Coats' disease.

Surgical management of advanced coats' disease has always been a challenge to a surgeon. Various different techniques have been tried. With the advancement in surgical instruments and machines, surgeons are now modifying older surgical techniques. We have tried a novel minimally invasive surgical technique for the management of advanced coats' disease patient having high bullous exudative retinal detachment. Intravitreal injection of Bevacizumab at the end of the surgery has a role in such cases.

Introduction

Coats' disease is a rare congenital retinal disorder which also known as “exudative retinitis or retinal telangiectasis.” The leakage from the abnormal vessels leads to partial or complete detachment of the retina. Coats' disease has remained a cause of severe visual loss even a century after its origin. Usually, the aim is to salvage the eye as visual outcome is obscured in advanced Coats' disease cases. Management of Coats' disease varies depending on its stage of the disease. Early stages of Coats' disease with abnormal telangiectatic vessels can be managed with cryotherapy or laser therapy alone. Advanced cases have been difficult to manage with poor to nil visual prognosis. Consensus regarding the best effective surgical management has not been achieved. We have tried a novel surgical technique in a female child presented with unilateral Coats' disease.

Case Report

A 4-year-old female child was presented to us by her parents after they noticed white reflex in the left eye (LE) for the first time. On examination, her visual acuity in the right eye (RE) was 6/9 and LE was perception of light with inaccurate projection of rays. Anterior segment evaluation revealed clear cornea with quiet anterior chamber with clear lens in RE and clear cornea with quiet anterior chamber with flares Grade I and no cells with no neovascularization or ectropion uvea with relative afferent pupillary defect Grade I in LE. After dilatation on fundus examination, RE revealed healthy disc with normal macula and normal retinal blood vessels and LE revealed total bullous exudative retinal detachment with subretinal exudation and dilated telangiectatic vessels in inferior quadrant [Figure 1]. Clinical impression was of LE Coats' disease. Ultrasonography of the LE revealed total retinal detachment with subretinal fluid (SRF) having mild to moderate echoes with normal globe contour and no evidence of mass or calcification. Computed tomography scan of the orbit and brain was done to rule out retinoblastoma. After confirming the diagnosis, SRF drainage with vitrectomy machine with bevacizumab injection and cryotherapy was advised for LE under very guarded visual prognosis.

Figure 1

Preoperative photograph showing high bullous exudative retinal detachment with telangiectatic vessels inferiorly

Surgical technique

After localizing highest point of SRF pocket, posterior sclerotomy made using microvitreoretinal blade or with introduction of 23 G trocar and cannula taking care not to penetrate through the retina allowing passive drainage of SRF [Figure 2]. After cessation of SRF passage, the remnant can be aspirated actively using vitrectomy platform along with balanced salt solution infusion cannula to maintain the intraocular pressure and help in expelling the SRF [Figure 3]. Drainage of SRF has to be done under constant visualization of the retina to detect any incarceration. Thereafter, 360° transconjunctival cryopexy was done to ablate abnormal vessels and further exudation. Bevacizumab injection injected intravitreally at the end of procedure. SRF was sent for cytological evaluation, which revealed lipid-laden macrophages, suggestive of Coats' disease. There were no malignant cells, thus ruling out retinoblastoma. Postoperatively, on examination, LE revealed attached retina with well-ablated telangiectatic area [Figure 4].

Figure 2

Passive drainage of subretinal fluid with infusion onto maintain intraocular pressure (arrows showing direction of flow)

Figure 3

This photograph describes active aspiration of remaining fluid by vitrectomy machine when passive drainage is over

Figure 4

Postoperative image showing well-attached retina

Discussion

Initially, advanced stages of coats disease was considered as nontreatable and patients had complications such as neovascular glaucoma. Silodor et al.[1] showed a series of 13 patients, for whom neovascular glaucoma could be prevented through subretinal drainage and cryotherapy. In their study, all untreated eyes required enucleation.

In advanced stages of Coats' disease having exudative retinal detachment with abnormal telangiectatic vessels, the aim of the surgery has always been to settle the retina with SRF drainage and ablate the abnormal vessels with cryotherapy or laser therapy to prevent further exudation. Proper selection of procedure is very important for ultimate outcome of the surgery.

In a review of patients with advanced Coats' disease, treated with various techniques, Adam et al. have found that external drainage with cryo/laser ablation was sufficient to reattach the retina. In their review of six patients treated with external drainage, one had persistent SRF up to 4 months, for which the second surgery was done.[2] Along with this case, we have also tried this modified technique of additional active aspiration of fluid in another two cases. All the patients are doing well with attached retina at the end of follow-up of 6 months without any complications or persistent detachment.

A study of 15 cases by Mrejen et al. proved that carefully selected treatment can improve anatomical stability of almost each eye with Coats' disease complicated by retinal detachment.[3] Scleral buckling with vitrectomy along with SRF drainage with silicon oil was tried by Schmidt-Erfurth and Lucke in eight patients with advanced Coats' disease.[4] Three patients retained useful vision (20/500–20/700), but complications from silicone oil occurred in two patients requiring removal of silicone oil in one patient. One of the purposes for this technique was to avoid vitreous removal and silicon oil injection to prevent silicon oil-induced complications in the future.

Kranias and Krebstried vitrectomy with membrane peeling and internal fluid gas exchange without employing sclera buckle in patients with advanced Coats' disease as they believe that retinal detachment in Coats' disease is due to combined exudative and tractional mechanisms.[5]

With the proven role of bevacizumab in preventing new vessels formation, it also now used at the end of the procedure. Anti-vascular endothelial growth factor (VEGF) has been tried perioperatively or intraoperatively as they have a role in reducing the exudation by decreasing vascular permeability along with their VEGF blockade action. Waite et al. have reported one case report discussing the role of perioperative anti-VEGF in the treatment if Coats' disease. A 15-year-old male child was treated with anti-VEGF to prevent exudation.[6]

We tried a new technique of external transscleral fluid drainage initially passive drainage and then active aspiration with aspirating cannula of vitrectomy machine. After attaching the retina, we applied cryotherapy to ablate abnormal vessels. Injection avastin was injected at the end of procedure. This technique being less invasive/traumatic helps in early recovery with good postoperative outcome.

Conclusion

Patients presenting with advanced stages of Coats' disease having bullous exudative retinal detachment have very guarded visual prognosis. Anatomical stability of the eye, especially in children, should be aimed with procedures with minimal invasion, less recurrence, and less future complications. Our technique of external transscleral drainage (passive and active both) with cryotherapy reduces the chances of persistent fluid and thus resurgeries and seems to be a good option with minimal invasion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.