Endoscopic Anterior Transmaxillary Approach to the Lateral Middle Skull Base: An Anatomical Study and Clinical Application

Background: The lateral middle skull base involves the upper parapharyngeal space, the pterygopalatine fossa and the infratemporal fossa. Many open surgical approaches including maxillary swing, infratemporal fossa, have been designed to treat the lesions in this area. However, endoscopic transmaxillary approach to the lateral middle skull base has not been reported.

Objectives: We present an anatomic study for the lateral middle skull base with endoscopic transmaxillary approach, and assess the feasibility of and define the anatomical landmarks for an endoscopic anterior transmaxillary approach to the lesions involved the lateral middle skull base.

Materials and Methods: Six fresh injected cadaver heads (12 sides) were prepared for dissection of the middle skull base. Endoscopic anterior transmaxillary approach combined with transnasal approach to the lateral middle skull base was developed to define possible surgical landmarks. We then used this approach in six patients with tumors that involved the lateral middle skull base and provide their detailed clinical case reports

Result: Endoscopic anterior transmaxillary approach could expose the detailed anatomical structures around the lateral middle skull base involved the upper parapharyngeal space, the pterygopalatine fossa and the infratemporal fossa. This approach could be divided into the following stages: (1) opening of the ipsilateral paranasal sinuses, (2) entry into the maxillary sinus, (3) exposure of the pterygopalatine fossa and the infratemporal fossa, (4) exposure of the lateral middle skull base. In combination with an endonasal transpterygoid approach, Endoscopic anterior transmaxillary approach provided excellent surgical access to the lateral middle skull base. The pterygoid process, vidian canal, foramen rotundum, foramen ovale, sphenopterygoid fissure, infratemporale crest could be considered as the safe surgical landmarks for this approach.

Conclusion: Endoscopic anterior transmaxillary approach to the lateral middle skull base is technically feasible and has certain advantages in the lesions involved the lateral middle skull base. This approach could be ideal for the lesions that involved the paranasal sinuses, pterygopalatine fossa, infratemporal fossa, Meckel’s cave, cavernous sinus, and lateral middle skull base, such as schwannoma, adenoid cystic carcinoma, and recurrent nasopharyngeal carcinoma.

Keywords: endoscopic, Skull base, Tumor, Anterior transmaxillary, Surgical technique

No conflict of interest has been declared by the author(s).