Risk factors for orbital implant exposure after evisceration: A case control study of 93 patients

Purpose: The study aims to analyze risk factors for exposure of orbital implants after evisceration by comparison of patients with and without exposure of implants. Methods: This is a case control study in retrospective interventional case series; Group A- implant exposures after evisceration, Group B - Patients on follow up after evisceration with implant, without exposure, with matched duration of follow up. The sample size is calculated for a power of 80. Results: Group A comprised 32 sockets with implant exposure, presenting at median 18 months after surgery; Group B included 61 eviscerated sockets, without implant exposure, with follow up median 36 months. Odds Ratio (OR) was calculated; infected eyes -OR 1.3, P = 0.6; phthisical eye - OR 1.4, P = 0.43; multiple prior surgeries- OR 1.55, P = 0.33. Group A had 59.3% porous implants, Group B 55.7%, - OR 1.3, P = 0.5. Mean implant size in Group A 19.06 mm, Group B 18.78 mm- showed no statistical difference. Multiple logistic regression analysis showed no significant risk factor for exposure. Surgeon factor was not analyzed since there were multiple surgeons. Conclusion: This is the first study with calculated sample size, comparing implant exposure patients to a control group. Porous implant material, presence of infection, phthisical scleral shell, and prior surgery showed higher trend of exposure (Odds ratio >1), but none was conclusive. Larger size of implant was not a risk factor for exposure. Eliminating the role of several factors in implant exposure allows the surgeon to make better surgical choices: such as place an implant of appropriate size, of a material of surgeon's choice, and do primary placement of implant in a patient with evisceration post-corneal ulcer or endophthalmitis. A hypothesis and a recommendation is that meticulous attention be paid to surgical technique.

Treatment of Exposed Hydroxyapatite Orbital Implants Wrapped with a Synthetic Dura Substitute

PURPOSE: To describe cases of exposed hydroxyapatite (HA) implants wrapped with the synthetic dura substitute Neuro-Patch treated via simple Neuro-Patch removal. METHODS: The medical records of seven patients who experienced exposure of their HA implant were reviewed. All patients had been enucleated and implanted with HA wrapped with Neuro-Patch. For treatment, Neuro-Patch was removed to the greatest extent possible. After applying local anesthesia with lidocaine, blunt dissection was performed to separate the conjunctiva and Neuro-Patch via the site of exposure. Pressure was applied to the remaining Neuro-Patch with forceps and removed with scissors. RESULTS: Neuro-Patch was visible at the area of exposure in all patients. No surgery beyond initial Neuro-Patch removal was necessary in six of the seven patients. In five cases, the exposed area began to heal rapidly after Neuro-patch removal without primary closure of the defect. In one case, the Neuro-Patch material and all necrotic tissue was removed aggressively due to inflammation around the orbital implant. Lastly, an infection was noted in one case, prompting complete removal of the Neuro-Patch–wrapped HA implant. CONCLUSIONS: Wrapping material may hinder implant vascularization. Exposure of HA in wrapped implants can be successfully treated by a simple removal procedure if detected and managed early.

The Effect of 4 Rectus Muscle Anterior Displacement in Porous Polyethylene Orbital Implant Exposure

PURPOSE: To investigate the effects of anterior displacement of four rectus muscles in exposure of porous polyethylene orbital implant (Medpor(R)). CASE SUMMARY: This retrospective study reviewed 4 eyes with exposed orbital implant who underwent evisceration with porous polyethylene orbital implant (Medpor(R)). The technique involves dissection of conjunctiva and tenon's capsule and isolation of four rectus muscles from sclera. Unsure if each muscle was sutured to each other or if a group of muscles were sutured to another group (i.e. superior and inferior to medial and lateral). Posterior tenon's capsule was closed interruptedly and conjunctiva was closed continuously. Orbital implant exposure was occurred at 2~36 months later after evisceration and implant insertion. One eye was noted wound dehiscence 1 week after operation, then re-suture was done. Re-exposure was notified in 1 eye at postoperative 3 months, but it was small, then we just observed. In other 3 cases, exposure was not identified till last follow up. CONCLUSIONS: Four rectus muscle anterior displacement procedure may be simple and useful method in exposure of orbital implant.