Closure of mid-posterior Tenon's capsule in enucleation.

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.