gms | German Medical Science

Objective: The pterygopalatine fossa is located between the posterior wall of the maxillary sinus and the pterygoid plates and therefore deep in the skull base. Surgical access to tumors arising from or invading this region is therefore challenging. The endoscopic transnasal transmaxillar approach provides a minimal-invasive route to access this region. It is associated with less morbidity than traditional microscopic transcranial or transfacial approaches, while providing better visualization. We aimed to explore the feasibility of this approach based on our clinical experience.

Methods: Patients harboring pathologies involving the pterygopalatine fossa were evaluated in this study. The surgical corridor included a mega-antrostomy and medial maxillectomy with removal of the posterior wall of the maxillary sinus. A prelacrimal window maximized the access to the anterolateral maxillary sinus while preserving the inferior turbinate and the nasolacrimal duct. The surgical treatment was performed by an interdisciplinary skull base team comprising one neurosurgeon and one otorhinolaryngologist. Neuronavigation and neurophysiologic monitoring, including dynamic electromyography (EMG), motor evoked potential (MEP), and somatosensory evoked potential (SSEP) of the Vth nerve was furthermore applied. A micro-doppler probe was utilized to locate important vessels.

Results: A total of four patients (n=4) were operated via this approach in our department between September 2019 and November 2020. Patients’ age ranged from 14 to 79 years of age. The tumor pathologies comprised meningiomas (n=2), a neurinoma (n=1) and one juvenile nasopharyngeal angiofibroma (JNA) (n=1). No postoperative complications could be registered. In two cases a submaximal resection was achieved due to V3 involvement and the associated risk of nerve injury. In the patient harboring a JNA, a small residual tumor adherent to the internal carotid artery was left to avoid rupture. Overall, a good surgical reduction of tumor tissue and in one case a complete removal was achieved.

Conclusion: The endoscopic transnasal transmaxillar approach with rod lens endoscopes to the pterygopalatine fossa is a feasible surgical corridor with low morbidity. The prelacrimal route is an essential improvement to traditional endoscopic transmaxillar approaches that increases access and freedom of movement to the anterolateral maxillary antrum. An experienced interdisciplinary team is the essential backbone for this type of surgeries.