Comparison of vascularization of Medpor and Medpor-Plus orbital implants: a prospective, randomized study

To compare vascularization of porous polyethylene (Medpor) and porous polyethylene with synthetic bone graft particulate (Medpor-Plus) orbital implants following enucleation.

Prospective, randomized study involving 10 patients. A standard enucleation procedure was performed, and each patient was randomized to receive either Medpor or Medpor-Plus orbital implant with anterior scleral cap technique. Gadolinium-enhanced, 3-Tesla MRI was performed at 1.5 months, 3 months, and 4.5 months following surgery. Implant vascularization was calculated in axial, coronal, and sagittal planes with manual planimetric method using postcontrast T1-weighted Digital Imaging and Communications in Medicine images.

The mean area of implant vascularization at 1.5 months, 3 months, and 4.5 months for Medpor implants was 58%, 70%, and 75%, respectively, and for Medpor-Plus implants was 69%, 76%, and 85%, respectively. The mean vascularization of Medpor-Plus implants was more than Medpor implants at 1.5 months (p = 0.008), 3 months (p = 0.09), and 4.5 months (p = 0.003). The difference between the 2 groups assessed by repeated measures analysis of variance was statistically significant (p < 0.0001). During the mean follow-up of 36.7 months (range, 18-43 months), 1 patient in the Medpor group had implant exposure that responded to scleral patch graft.

Implant vascularization is faster with Medpor-Plus implants compared with Medpor implants when assessed by a planimetric method using 3 Tesla MRI. The addition of synthetic bone graft particulate (Novabone) to porous polyethylene may enhance implant vascularization.