Retrobulbar Injections May Be An Option in COVID-19 Orbital Mucormycosis

Retrobulbar injection of amphotericin B is nearly safe and may provide an alternative intervention to orbital exenteration for patients with COVID-19 associated rhino-orbito-cerebral mucormycosis (CAM), according to a systematic review published in Ophthalmic Plastic and Reconstructive Surgery. Retrobulbar injection of amphotericin B may also save vision, according to the report. 

“Following COVID-19 infection a rising count of rhino-orbito-cerebral mucormycosis is observed, requiring orbital exenteration, a disabling lifetime affecting surgery,” the study authors explain. “One of the potential interventions for globe salvage in these patients is retrobulbar injections of amphotericin B.”

Researchers searched PubMed, Scopus, Web of Science, and Embase databases and all English studies with the confirmed diagnosis of CAM infection were included in the review. The research team identified 647 cases with a history of retrobulbar injections(s) of amphotericin B in 13 studies involving 3,132 participants (70.7% men, age range, 11-75 years) with CAM. 

Among patients with CAM, diabetes mellitus was the most common comorbid condition (2381/3048, 78.1%), and the use of systemic corticosteroids associated with COVID-19 treatment was the most common risk factor (2256/2588, 87.2%). 

The most frequent protocol for retrobulbar injections was 1 ml of 3.5mg/ml liposomal amphotericin B for 3 doses daily or on alternate days. The researchers explain that the globe salvage rate was 95.0% (494/520) in eyes with a history of retrobulbar injection(s). 

They found that the total rate of orbital exenteration was 14.9%, irrespective of the history of retrobulbar injection of the drug. Other outcomes of retrobulbar injections were vision salvage and a decrease in ophthalmic signs such as visual impairment, pain, swelling, ptosis, proptosis, and extraocular motility restriction.

The team reports that the side effects of this intervention were not severe, and most of them were transient. Side effects included swelling at the injection site, restriction of ocular motilities, worsening of orbital inflammation, and aggravation of visual impairment in a few cases. 

The researchers suggest that retrobulbar injection of amphotericin B may save vision. They also believe that retrobulbar injections can be considered an alternative intervention to orbital exenteration in patients with CAM.  

“Orbital [magnetic resonance imaging] with contrast is useful to evaluate patients needing retrobulbar injections. By this imaging technique, the extension of the infection and the presence of the devascularized tissue can be assessed,” according to the study authors. “Tissues with enhancement are compatible with infectious sites and benefit from retrobulbar administration of the drug, but devascularized tissues have no contrast enhancement and benefit from debridement rather than antifungal treatment.”

Limitations of the review include failure to perform a statistical analysis and possibility of bias due to only considering studies that performed retrobulbar injection of amphotericin B.