A Randomized Controlled Trial on Outcomes of Polymethylmethacrylate and Hydroxyapatite Implants in Evisceration: Introducing the Four-Petal Myoconjunctival Technique

Objective: To compare the success rate of scleral-wrapped polymethylmethacrylate (PMMA) and hydroxyapatite (HA) orbital implants in primary evisceration using the four-petal myoconjunctival technique. Materials and Methods: A randomized controlled trial was conducted. All enrolled patients underwent primary evisceration with the four-petal myoconjunctival technique. The primary outcome measured was the success rate of wearing an ocular prosthesis eight weeks post-surgery without complications. Secondary outcomes included orbital implant motility, prosthetic motility, and the incidence of post-operative complications. Results: Thirty-one patients were analyzed, with 17 patients in the PMMA group and 14 in the HA group. The success rate for wearing an ocular prosthesis was 100% in the PMMA group and 93% in the HA group (p=0.45). At eight weeks postoperatively, orbital implant and prosthetic motility were comparable between the PMMA and HA groups across all gaze directions. Mean implant movements in both groups ranged from 3.8 to 5.6 mm, with no statistically significant differences between them (p>0.05). One patient in the PMMA group experienced wound dehiscence, while one in the HA group developed a conjunctival cyst. Conclusion: At eight weeks, both wrapped PMMA and HA implants showed comparable outcomes in prosthesis wear and motility. The four-petal technique was effective with minimal complications, making PMMA a practical option in resource-limited settings.