Clinical toleration and presentation of corraline and synthetical hydroxyapatite implants in situ by means of a 20 MHz ultrasonic probe
A. G. Norda , A. Thomas, J. Steinhauer, H.-W. Meyer-Rüsenberg
Introduction: Naturally produced coralline hydroxyapatite implants has been used since 1993 in our clinic after enucleation. Synthetically produced hydroxyapatite has been available since 1996. In a study done in 1999, the question to be answered was whether there was a clinically determinable difference due to the tolerance of both materials and whether the implants could be detected and presented by a 20 Mhz ultrasonic probe.
Methods: Our report deals with the results of 25 patients: 14 which were provided surgically with a coralline implant and 11 with synthetically produced hydroxyapatite. The mean period of observation was 23.6 months. The aim of the study was to collect data due to the tolerance and flexibility of the implants, the position of the artificial eye, the positioning of the eyelids and conjunctival shape. For the first time an attempt was made to clinically assess the implant in situ by means of an ultrasonic probe (20MHz).
Results: The subjective tolerance of all the implants was about 90%. There was significant artificial eye retraction of between 1 and 3mm for 68% of all the implants. After implantation of coralline hydroxyapatite, an ectropion appeared in 40% of the cases. In the group of patients with a synthetic implant, upper lid ptosis was found in 40% of the cases. By means of the 20 Mhz probe, the anterior orbital structures and frontal pole of the hydroxyapatite implants were able to be represented. Surface structures (conjunctiva and tenon, inclusion cysts, PEG drill holes, muscle bases) were able to be recognized. A differentiation could not be made between the degree of vascularization or type of implant.
Discussion: Both types of hydroxyapatite prove to be easily tolerable implants with satisfactory aesthetic results. Ptosis and ectropion are shown to be a frequent complication. Assessment of the implant by means of ultrasound is only possible in the anterior third and provides little evidence for diagnosis. The classical methods (CT and MRI) continue to be necessary for a more precise examination of the entire implant.
The Eye Clinic of St. Josefs Hospital and Witten-Herdecke University