The effect of enucleation on orbital growth in patients with retinoblastoma.

PURPOSE: To measure orbital volume using serial magnetic resonance imaging (MRI) scans to determine the effect of enucleation on orbital growth over time.

METHODS: The medical records of patients who underwent unilateral enucleation for retinoblastoma with a minimum of 2 MRIs were retrospectively reviewed. Orbital asymmetry was calculated using MRI measurements. Nonlinear and linear mixed effect regression models were used to predict the effect of age at time of enucleation on degree of orbital asymmetry.

RESULTS: A total of 27 patients were included (mean age at enucleation, 2 years; range, 2.5 months to 5 years). Age at scan (P = 0.046) and age at enucleation (P = 0.0006) were found to have a significant effect on orbital asymmetry. Change in orbital asymmetry over time was more pronounced after enucleation in children enucleated at <1 (P < 0.0001) or <2 years of age (P = 0.0109). Younger age at enucleation was associated with a greater degree of asymmetry over time, although this effect was extinguished for patients enucleated after the age of 3 years.

CONCLUSIONS: In patients with retinoblastoma, enucleation with orbital implant before 3 years of age has a significant effect on orbital volume asymmetry. After the age of 3, this effect appears to be less detrimental to the degree of orbital asymmetry.