Comparison between the Exposure Rates of Tutoplast(R) and Vicryl Mesh Used as Wrapping Materials for Hydroxyapatite Orbital Implant

PURPOSE: To compare the exposure rates of two wrapping materials for hydroxyapatite (HA) ocular implants (Tutoplast(R) vs. vicryl mesh). METHODS: We reviewed the medical records of 137 eyes of 137 patients who had received intraorbital HA implantation from March 1997 to March 2001. RESULTS: We used Tutoplast(R) in 72 patients and vicryl mesh in 65 patients. The mean follow-up period was 22.1 months. Implant exposure developed in four cases of eyes using vicryl mesh. No case of exposure occurred in eyes using Tutoplast(R). The mean period from operation and implant exposure was 3.5 weeks (1.5~5 weeks). CONCLUSIONS: When vicryl mesh was used as the wrapping material for HA intraorbital implant it is advisable to pay more attention to the possible postoperative implant exposure than when Tutoplast(R) was used.

Usefulness of 99m Tc-MDP Bone Scintigraphy for Assessing Vascular Ingrowth on Hydrox yapatite Ocular Implant

This study was to evaluate the clinical usefulness of 99m Tc-MDP bone scintigraphy for assessing vascular ingrowth into the ocular implants after enucleation and evisceration. Twenty four patients(M:F=7:17, mean age:36), with a coralline hydroxyapatite after uncomplicated enucleation or evisceration surgery were studied. Uptake ratio was also calculated by measuring the implants activity(H)and contralateral orbit activity(N). Grading score and uptake ratio were compared with clinical outcome of vascularization. Additionally, we also analyzed the vascularization status as time lapse between primary surgery and scintigraphic study and surgical methods. The degree of grade and uptake ratio were inversely correlated with vascular ingrowth. Higher than grade 2 or greater than 1.56 in H/N ratio seemed to be an indicator for better prognosis. 99m Tc-MDP bone scintigraphy can be a useful method to evaluate the vascularized status of implants. Adequate time for 99m Tc-MDP bone scintigraphy after enucleation and evisceration was 11~20 weeks.

Clinical Study of Vacularization of Hydroxyapatite Ocular Implants by 99mTc-MDP Bone Scan

Hydorxyapatite ocular implants, which are used to replace the volume of the orbit following enucleation and evisceration, allow the artificial eye to move. For this advantage, drilling is required to integrate peg into implant for transfer of motion. The earlier drilling, the earlier good results in cosmesis, but it should be done in the conditon of complete vascularization to reduce infection and exposure. To evaluate the proper timing for drilling and the difference of vascularization rate between standard eevisceration(group A) and modified evisceration(group B), we attempted to evaluate implant vascularization by using 99mTc-MDP bone scan prospectively at various intervals from 10 to 23 weeks(6 patients at 10-12 weeks, 29 patients at 13-16 weeks, 31 patients at 1720 weeks, and 7 patients as 21-23 weeks) after implantation. In 7 out of 73 patients postcontrast MRI was performed on the same day of 99mTc-MDP bone scan, we compared the degree of enhancement with that of uptake in each patients. In group A the ratio of complete graft vascularization was seen in 0% at 1012 weeks, 33% at 13-16 weeks, 50% at 17-20 weeks, and 67% at 21-23 weeks. On the other hadnd in group B it was seen in 50% at 10-12 weeks, 55% at 13-16 weeks, 55% at 17-20 weeks, and 75% at 21-23 weeks. It was increased with time. The time of complete vascularization was not different between group A and B. In 7 patients studied with both 99mTc-MDP bone scan and MRI, the degrees of vascularization were very similar on the two examinations in each patients. We would like to suggest that it is proper to perform 99mTc-MDP bone scan at 21 weeks after implantation regardless of surgical methods. 99mTc-MDP bone scan is more economic than postcontrast MRI for evaluation of complete vascularization in hydroxyaptite implant.