Experimental effects of intraorbital tissue expansion on orbitomaxillary growth in anophthalmos.

A skeletal growth study evaluating an intraorbital tissue expander as a globe replacement in anophthalmos was conducted in an infant animal model. Twenty-one 21-day-old kittens were equally divided into the following three groups: a control, a unilaterally enucleated, and an enucleated-expanded group. Postoperative three-dimensional computed tomographic scans were obtained at 5 months of age immediately before study termination. Linear orbital, orbitomaxillary, and zygomaticomaxillary dimensions were measured on the scans and compared at necropsy with orbital volume assessment on the dry skulls. Control animal orbits averaged 21.5 mm in height, 21.0 mm in width, and 5.1 cm3 in orbital volume, and an orbitomaxillary-zygomaticomaxillary height-to-width ratio of 31.0: 24.5. The control side, its contralateral side, and the contralateral orbits of the treated sides were not significantly different. By study completion, enucleation resulted in a significant loss of orbital volume (mean, 1.9 cm3; p < 0.001) confirmed by deficient orbitozygomaticomaxillary measurements. The expanded orbits showed no loss of volume (mean, 5.2 cm3; p > 0.1) and normalization of all linear midfacial structures. This study demonstrates that early expansion emanating from within the orbital soft tissue positively affects both the skeletal and lid anomalies associated with congenital globe loss or early enucleation.