Closure of mid-posterior Tenon's capsule in enucleation

Abstract

Purpose: To evaluate the potential advantages of closing mid-posterior Tenon's capsule during enucleation surgery by comparing its thickness and relative tissue strength with anterior Tenon's capsule. To evaluate surgical outcomes of enucleation using mid-posterior Tenon's capsule closure.

Methods: This is an experimental laboratory study and retrospective surgical case series. Histologic examination of Tenon's capsule was performed on permanently fixated human orbital specimens. Suture pull-out testing as a measure of tissue strength was performed on anterior and mid-posterior Tenon's capsule in nonfixated human cadaver orbits. A retrospective review of enucleations with primary orbital implant placement performed by the authors between 1998 and 2008 was conducted to determine the surgical outcomes of enucleation using closure of mid-posterior Tenon's capsule.

Results: Histologic analysis showed the average thickness of mid-posterior Tenon's capsule to be 121% greater than that of the anterior portion (518 vs. 234 μ, p < 0.001). Suture pull-out strength was 84% higher in mid-posterior versus anterior Tenon's capsule (741 vs. 1298 g, p = 0.016). Of the 103 enucleations performed by the authors (54 with unwrapped silicone implants and 49 with unwrapped porous polyethylene), there were 2 cases (1.9%) of implant extrusion and 1 case (1%) of implant exposure.

Conclusion: From a structural and biomechanical standpoint, mid-posterior Tenon's capsule is significantly thicker and stronger than anterior Tenon's capsule, theoretically providing a superior barrier to orbital implant exposure and extrusion after enucleation.