Challenges in management of congenital enophthalmos due to anomalous accessory orbital extraocular muscle bands.

Introduction: Congenital enophthalmos is a rare condition characterized by posterior displacement of the globe, often associated with bony orbital anomalies or whole globe development defects. The purpose of this report is to present two unrelated cases of congenital enophthalmos secondary to anomalous accessory orbital bands and to describe characteristics of orbital imaging that differentiate this condition from the other causes.

Methods: The case records of two patients who presented with congenital enophthalmos and were discovered to have anomalous accessory orbital extraocular muscle bands were reviewed. The clinical features, initial diagnosis, high resolution magnetic resonance imaging (MRI) findings, and surgical outcomes were noted. A 3-dimensional reconstruction model was used to understand the approach and surgical management in one of the cases.

Results: Both patients presented with unilateral severe enophthalmos, globe retraction, and restricted ocular motility in all directions since birth. High-resolution MRI of the orbits revealed a short anomalous band, isointense to the muscle, arising from a rectus muscle belly and attaching to the posteroinferior part of the globe adjacent to the optic nerve. The caliber of the extraocular muscles and ocular motor nerves was normal. In one patient, surgery was not pursued due to the extreme posterior location of the band with proximity to the optic nerve. In the other patient, the deviation did not improve, despite successfully severing the accessory band, due to extensive scarring.

Conclusion: Anomalous accessory orbital extraocular muscle bands are a rare and often overlooked cause of congenital enophthalmos when associated with limited ocular motility. Imaging the orbit can aid in diagnosis and help differentiate it from other causes. Safe surgical approaches to address the problem are limited, and available approaches may not be effective. These two cases highlight that the management of accessory extraocular muscle bands causing enophthalmos can be extremely challenging and difficult to improve even with intensive surgical intervention.