Abstract
Purpose: :
Orbital growth retardation is a known complication in children undergoing enucleation for retinoblastoma. There are many materials available for orbital implantation after enucleation, but it is unknown which, if any, stimulate orbital growth. Porous implants that allow vascular ingrowth have improved motility and may provide a stronger mechanical stimulus for continued, symmetric growth of the enucleated orbit versus traditional solid implants. The purpose of this study is to compare the difference in orbital growth in patients treated with porous hydroxyapatite (HA) implants versus solid silicone implants.
Methods: :
A retrospective review was performed of all patients with retinoblastoma who underwent unilateral enucleation at one institution from 1969–1999. Patients who received external beam radiation or systemic chemotherapy were excluded. CT and/or MRI were used to compare the difference in orbital volumes in the enucleated orbit to the contralateral orbit in 13 patients who underwent enucleation with HA implants versus 20 patients who underwent enucleation with silicone implants.
Results: :
The mean difference in orbital volumes between enucleated vs. nonenucleated orbits was 0.9± 0.64 cm3 for patients treated with HA implants vs. 0.62± 0.41 cm3 in patients treated with silicone sphere implants (p=0.7367). The median age at enucleation was 29 months and 16.5 months respectively. The median follow–up time was 137 and 144 months respectively. The median size of the implant was 18 mm and 16 mm respectively.
Conclusions: :
There was no statistically significant difference in size of orbital volume based on the type of implant used, the age at enucleation, the time to follow–up or the size of implant.
Keywords: orbit • development • retinoblastoma