Background. The periorbita has been traditionally regarded as the decisive layer whose involvement in carcinoma of maxillary sinus indicates orbital exenteration. Anatomic texts depict that the orbital fat rests on the periorbita. Our experience at surgical dissections has been different.
Methods. Twenty-five patients underwent total maxillectomy for advanced (T3-T4) carcinoma of the maxillary sinus with postoperative radiotherapy during a 15-year period between 1981 and 1995. In 11 patients, despite radiologic evidence of orbital invasion, and in 5 patients with infiltration of the periorbita, the eye could be preserved without evidence of recurrence. In 6 patients who in addition underwent orbital exenteration, histopathologic evidence of tumor invasion of the orbit was present in only one surgical specimen.
Results. Clinicoanatomic studies have clearly shown the presence of a thin, distinct fascial layer which surrounds the periocular fat and separates it from the periorbita. Neither clinical examination nor imaging could predict orbital invasion with ab-solute accuracy. Histopathologic examination of the surgical specimens shows that tumor infiltration of the eye is rare.
Conclusion. Periocular fat is surrounded by a thin fascial layer and is not in direct contact with the periorbita. Intraoperative decision making with respect to preservation of the eye is sometimes essential.