Biportal endoscopic transorbital approach: a quantitative anatomical study and clinical application.

Abstract

We devised a biportal endoscopic transorbital approach (BiETOA) to gain surgical freedom by making a port for the endoscope and investigated the benefits and limitations of BiETOA. A cylindrical port was designed and 3-D printed using biocompatible material. The port was inserted through a keyhole between the superolateral side of the orbital rim and the temporal muscle. An endoscope was inserted through the port, and other instruments were inserted through the conventional transorbital route. BiETOA was used to dissect eight cadaveric heads, and the angle of attack and surgical freedom were assessed. The mean maximal angle of attack was significantly different in BiETOA and endoscopic transorbital approach (ETOA) (P < 0.01) but not in BiETOA and ETOA lateral orbital rim (LOR) osteotomy (P = 0.207, P = 0.21). The mean surgical freedom was significantly different in BiETOA and ETOA (P < 0.01) and in BiETOA and ETOA LOR osteotomy (P < 0.01). In the clinical cases, tumors were removed successfully without any complications. BiETOA provided increased surgical freedom and better visibility of deep target lesion and resulted in good surgical and cosmetic outcomes.