Artikel
Transconjunctival endoscopic approaches to the orbit: A cadaver study
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Veröffentlicht: | 4. Juni 2012 |
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Gliederung
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Objective: Standard approaches to the orbit, except for transnasal approaches, involve large skin incisions in most cases and also a craniotomy. In order to evaluate less invasive surgical approaches to the orbit, a study was designed assessing endoscopic transconjunctival approaches.
Methods: Using a 30° / 3 mm and a 0° / 6 mm rigid endoscope, neuronavigated transconjunctival approaches to the orbit were performed on 4 cadavers. A special endoscopic headframe was designed for this study in order to avoid injury of anatomical structures due to excessive movement of the endoscope tip in the orbit. On each eye, a lateral and medial transconjunctival supra- and infrabulbar endoscopic approach to the extra- and intraconal space were performed. The size of the incision, maximal depth of penetration in the extra- and intraconal space and the distance from the orbital rim to the optic nerve were measured.
Results: All four approaches showed a good exposure and good access to the extra- and intraconal space. The mean size of the transconjunctival incision for the approach was 10.4 mm. The optic nerve could be exposed through all four approaches. The mean maximal depths of penetration in the extraconal space were 28.6 mm for the 30° / 3 mm and 20.7 mm for the 0° / 6 mm endoscope. In the inraconal space the mean maximal depth of penetration was 23.8 mm for the 30° / 3 mm and 19.4 mm for the 0° / 6 mm endoscope. Based on the acquired measurements a new surgical classification of the orbit in quadrants and zones was made for endoscopic procedures.
Conclusions: Transconjunctival endoscopic approaches to the orbit allow a maximal exposure of the extra and intraconal space through a minimally invasive approach. None of the approaches required a muscle transsection. Infrabulbar approaches have better cosmetic results then suprabulbar approaches which require incision of the eyelid.