VITRECTOMY

Postoperative endophthalmitis remains a rare but potentially serious complication of vitrectomy surgery with a very poor visual prognosis for affected patients, according to a study presented at the French Society of Ophthalmology (SFO) annual meeting.

“Vitrectomy is a fairly frequent surgical procedure for a range of ocular problems but serious complications are rare with an incidence of endophthalmitis after pars plana vitrectomy of less than one per cent,” said Clemence Virevialle MD. She added, however, that the visual prognosis is usually very poor and that more prospective studies are needed to help understand possible risk factors for post-vitrectomy endophthalmitis

Presenting a retrospective analysis of post-vitrectomy endophthalmitis treated at the Quinze-Vingts Hospital in Paris between 2008 and 2013, Dr Virevialle said that 31 cases requiring hospitalisation had been identified in that period. The mean patient age was 65.9 years, ranging from 33 to 84 years. Eight of the treated patients had diabetes.

The mean delay for diagnosis of endophthalmitis was five days after the vitrectomy surgery, with 90 per cent of the cases detected in the first postoperative week. Most of the vitrectomies were performed as part of epiretinal membrane procedures (19 patients), with the remaining cases concerning silicone oil removal +/- cataract surgery, retinal detachment, retained lens fragments, diabetic retinopathy and macular hole.

Bacterial analysis

Bacterial analysis identified the causative organisms of the post-vitrectomy endophthalmitis in 17 patients: staphylococcus in 10 patients, seven of which were staphylococcus epidermidis; streptococcus in two patients; the rest were divided between Gram-positive cocci, various bacillus strains and one case of Candida endophthalmitis.

Dr Virevialle said that the visual acuity outcomes associated with endophthalmitis following pars plana vitrectomy (PPV) are generally poor. In the study, there was an improvement of visual acuity in 16 patients after hospitalisation, while three patients lost visual acuity and eight patients remained stable. The final visual acuity depended on the underlying pathology and the initial visual acuity before surgery.

She said that bacteria in the conjunctival flora were responsible for most cases of post-vitrectomy endophthalmitis. With this in mind, she advised preoperative application of povidone-iodine to the eyelid margins, eyelashes and conjunctival ocular surface to reduce the risk of infection.

The major risk factors of endophthalmitis after small-gauge vitrectomy remain uncertain, but particular attention should be paid to diabetic patients, who comprised 26 per cent of affected patients in Dr Virevialle’s group. The type of intervention may also be significant, she said, with two-thirds of patients being operated for epiretinal membranes. Other potential predisposing factors to watch for include vitreous wick in the sclerotomies, less vitreous removal during small-gauge vitrectomy and lower infusion rates in 25-gauge vitrectomy.

Clemence Virevialle: c.virevialle@gmail.com