Comparative Motility of Alloplastic Orbital Implants

Study Overview
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Brief Summary
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This study will evaluate the effect of posterior placement of orbital implants on their motility compared to intrascleral placement after evisceration .

Detailed Description
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Evisceration allows removal of the intraocular contents while preserving the sclera and normal extraocular muscle attachments. It is more advantageous than enucleation in patients in whom intraocular tumor is rules out. Maximizing orbital volume and restoration of movement are important aspects of a successful surgical outcome. Standard evisceration techniques do not allow placement of an implant larger than 13-16 mm which don't adequately replace the volume leading to postevisceration socket syndrome. Therefore, various techniques have been described to expand the scleral cavity and allow placement of a large implant including anterior sclerotomies, posterior sclerotomies, and disinsertion of optic nerve. Implant exposure is a terrible complication of evisceration with reported rates as high as 67%. Exposure of the implant can lead to infection, which usually mandates removal of the implant. Trying to minimize this risk, physicians intentionally place the implants posterior to the normal position of the globe. Some authors described placement of the implant posterior to posterior sclera which totally eliminated the risk of exposure. However, this deep seating of the implant may have deleterious effects on its motility. It can decrease implant-prosthesis interaction. In addition, retro-scleral placement of the implant moves it posterior to the pulleys that serve as the functional origins of rectus muscles. This relationship would be expected to alter the pulling directions of the rectus muscles after evisceration hindering effective implant motility. In this trial the investigators will try to study the effect of posterior placement of the implants on its motility after evisceration.

Official Title
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Comparative Motility of Retro-scleral and Intrascleral Orbital Implants After Evisceration

Conditions
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Anophthalmos; Acquired, Evisceration; Traumatic, Eye

Intervention / Treatment
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* Procedure: Evisceration with orbital implantation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who are candidates for evisceration Exclusion Criteria: Inability to provide independent, informed consent Significant preoperative motility abnormalities

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Retro-scleral placement of the implant<br>Surgical steps; Two anterior scleral relaxing incisions A 360° scleral incision around the optic nerve to disinsert it Two posterior scleral relaxing incisions The implant is inserted posterior to posterior scleral edges The posterior sclera is closed then the anterior sclera is overlapped and closed. The implant is completely seated in the intraconal space | Procedure: Evisceration with orbital implantation<br>* Evisceration will be performed. Alloplastic orbital implant will be inserted either posterior to the sclera or partly within the scleral canal.<br>|
| Active Comparator: Intrascleral placement of the implant<br>Anterior and posterior sclerotomies with the implant partly in the scleral shell and partly in the intraconal space. Anterior relaxing sclerotomies not reaching the optic nerve A 360° scleral incision around the optic nerve. The anterior sclera flaps are overlapped and closed Part of the implant remains in the scleral shell, while the remaining part is sitting in the intraconal space. | Procedure: Evisceration with orbital implantation<br>* Evisceration will be performed. Alloplastic orbital implant will be inserted either posterior to the sclera or partly within the scleral canal.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Implant motility | The conjunctiva is marked at the center point of the implant while the patient looking in primary gaze. The excursion of the mark will be measured will a standard millimeter ruler in extreme gaze positions | 6 months | 
| Prosthesis motility | It will be measured with the kestenbaum's limbus test. Photographs will be taken while patients wearing Kestenbaum spectacles in vertical and horizontal directions of gaze. | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Volume augmentation | Exophthalmometry will be performed for all patients after fitting a prosthesis. Enophthalmos is to be graded from 1 to 4 (grade 1 = no postoperative improvement; grade 2 = improvement <2 mm but remained enophthalmos; grade 3 = improvement ≥2 mm but remained enophthalmos; and grade 4 = no enophthalmos) compared with unaffected side. | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Evisceration, Orbital implant, Implant position, Implant motility