Periorbital fascia, its significance in total maxillectomy.

In the surgical management of T3-T4 carcinoma of the maxillary antrum, involvement of the roof and/or erosion of the orbital floor, raises the possibility of the sacrifice of the orbital contents. While it is evident that the eyeball has to be sacrificed in the presence of gross disease, the indications when it can be preserved are not clear. Radiological assessment requires a minimum thickness of 4mm of the tissue. Standard anatomical texts describe the bony orbital floor and the orbital periosteum. In 1998 this author for the first time described a distinct fascial layer which encapsulates the orbital fat and termed it Periorbital Fascia. The purpose of this article is to draw attention to this anatomical structure and discuss the precise indications when the eyeball may be sacrificed or preserved. The conclusions are based on the experience with eighty two total maxillectomies for cancer performed over a period of 30 years. In the opinion of this author the following conclusions can be drawn. First, the orbital fat does not rest on the orbital periosteum as shown in anatomical texts, but is enclosed in a thin independent fascial layer termed the periorbital fascia. Secondly, in the event of malignant disease eroding the orbital roof, what is crucial is to know whether the orbital periosteum is involved and to know as to whether the disease process has reached the orbital surface of the periosteum. In case the disease is limited to the under surface of the orbital periosteum, the eyeball may still be preserved by a careful dissection between the periosteum and the periorbital fascia.