Transcaruncular Approach for Removal of Orbital Floor- A Cadaveric Model

Abstract

Abstract: : Purpose:The transcaruncular incision has been established as a direct approach for removal of the medial wall of the orbit in decompression surgery for Thyroid Ophthalmopathy. Additional decompression can be achieved by removal of orbital floor medial to the inferior orbital nerve. Achieving this traditionally requires a more extensive transconjunctival or Caldwell-Luc incision. In this study, in addition to the medial wall, we attempt to remove orbital floor medial to the inferior orbital nerve using only a transcaruncular incision. Methods:This study was performed on seven human cadavers; ten orbits were formalin fixed and four were freshly preserved. Using a 12 mm transcaruncular incision we removed as much orbital floor as possible, sparing the medial orbital strut and the inferior orbital nerve. Pre- and post-operative computed tomography was performed on the fresh specimens to illustrate removal of bone. After completion of dissection, orbits were exenterated followed by calculation of surface area removed. Results:Fourteen orbits were dissected using only a 12 mm transcaruncular incision. The average percentage of bone removed from the medial floor was 33.8% (s.d. 15.5%) Post-dissection examination revealed intact inferior orbital nerves in all specimens. Computed tomography of fresh orbits revealed partial removal of the medial aspect of the orbital floor with intact medial orbital struts. Conclusion:The transcaruncular approach to the medial wall can also be used to access the orbital floor between the medial orbital strut and the inferior orbital nerve. A moderate amount of orbital floor can be removed using this incision alone.

Keywords: 501 orbit • 431 imaging/image analysis: non-clinical • 315 anatomy