A study of the hydroxyapatite orbital implant drilling procedure.

PURPOSE: The hydroxyapatite orbital implant has been introduced as a buried, integrated implant for use in the anophthalmic patient. The second stage of the procedure involves drilling the implant and inserting a motility peg that allows direct coupling of the artificial eye to the implant. Other authors have advocated an assessment of implant vascularity by imaging prior to drilling. We aimed to see whether our practice of drilling after a predetermined time interval without assessment of implant vascularity would result in a higher complication rate. We also aimed to determine how successful the drilling procedure was in improving both the motility and the stability of the artificial eye. METHODS: The notes of 41 consecutive patients who underwent drilling were studied to determine the time interval between implantation with a hydroxyapatite sphere and drilling, the nature of any complications and any further surgical procedures undertaken. A postal questionnaire was sent to all patients asking them to grade the motility of their implant before and after drilling, and to state whether or not there had been any improvement in the stability of their artificial eye. RESULTS: The most frequent complication encountered was extrusion of the motility peg, which occurred in 3 patients. A total of 5 patients required redrilling. There was an 80% response rate to the questionnaire. Ninety-one per cent of patients felt that there had been an improvement in the motility of their artificial eye and 76% felt that the stability of their artificial eye had been improved. CONCLUSION: Pegging of the hydroxyapatite implant improves both the motility and the stability of the artificial eye in the majority of cases. Complications are infrequent and minor. If sufficient time is allowed after implantation for full implant vascularity to occur, it is not necessary to perform imaging studies. This practice does not result in an increase in complications, and significantly reduces the expense of the procedure.

A clinical study of the hydroxyapatite orbital implant.

The hydroxyapatite orbital implant has been used in the anophthalmic patient to give good motility of the artificial eye and a cosmetic result which matches that of the natural eye. It is thought to reduce the unacceptable complication rate that has been associated with other implants, as its buried, vascularized state deters extrusion and migration of the implant. Eighty consecutive patients were followed, 33 of whom had been referred for primary enucleation or evisceration, and 47 for secondary implant surgery. Thirteen of the secondary patients already had implants in situ. There were 44 males and 36 females in the study. The age range was 2.5 to 72 years with a mean of 36 years. The follow-up time was 2 to 30 months with a mean of 15 months. Twenty patients had been pegged at the time of review. A standardised operative and post-operative protocol was followed. The patients were assessed for the results of the motility of the artificial eye for both smooth pursuit and saccades, and for the cosmetic result. The amount of upper lid sulcus deformity was assessed to give an indication of volume replacement by the implant. The nature of any complications was noted as well as any further surgical procedures undertaken. The results show the hydroxyapatite orbital implant to give good cosmetic results with good motility of the artificial eye and to be associated with a low rate of complications. Drilling of the implant is simple to perform and also not associated with any significant complications. The hydroxyapatite orbital implant can be used successfully not only as a primary but also as a secondary or exchange implant with very few contraindications.

The hydroxyapatite orbital implant: a prospective study.

The hydroxyapatite orbital implant was first released for use as an orbital implant in humans in August 1989. It has been shown to be well tolerated, providing good motility of the artificial eye with a low complication rate when used as a primary implant. This prospective study evaluated the hydroxyapatite orbital implant used as both a primary and a secondary implant. Sixty patients were implanted between October 1992 and November 1994, 28 being implanted as a primary procedure at the time of enucleation or evisceration, and 32 as a secondary procedure. Seven patients underwent second-stage drilling and pegging of the implant. The mean follow-up time was 13 months (range 2-26 months). A standardised operative and post-operative protocol was followed. The patients were evaluated post-operatively for the amount of enophthalmos, degree of upper lid sulcus deformity, motility of the prosthesis, location of the implant in the socket, socket status and the presence or absence of discharge, position of the drill hole and coverage of the implant. Complications and their management were documented. Both patient and surgeon made a subjective assessment of cosmesis and the patient's satisfaction with the overall result was noted. The results of this study show the hydroxyapatite orbital implant to provide excellent motility of the artificial eye and good cosmesis with a low rate of complications when used both as a primary and as a secondary implant.

The 'baseball' orbital implant: a prospective study.

The 'baseball' orbital implant was described by Frueh and Felker in 1976. Although this implant was originally described for use as a secondary implant, it has also been widely used as a primary implant at the time of enucleation. This prospective study evaluated the effectiveness of this implant used both primarily and secondarily. Forty-four patients were implanted between April 1990 and May 1991, 19 of the implants being primary and 25 secondary. A standardised operative and post-operative protocol was followed. The mean follow-up time was 31 months (range 24-36 months). The patients were evaluated for the degree of volume replacement, implant and associated prosthesis motility, secondary eyelid and socket problems, patient satisfaction, the need for further surgery and post-operative complications. The overall results achieved by primary implantation were superior to those of secondary implantation. Our results suggest that this implant provides a satisfactory functional and cosmetic rehabilitation of the anophthalmic patient with few complications.