The Role of Transbasal Approach for Anterior Skull Base Tumors with Acute Visual Impairment

Introduction: As visual impairment is a common presentation of the parasellar tumors, the tumors located in the anterior skull base and craniofacial structures invading the optic canals (OCs) occasionally result in acute visual impairment from optic nerve compression. Our surgical policies in the management of these kinds of tumors extending into OCs are (1) avoiding disfiguring facial bone and skin incisions cosmetically, (2) selecting the appropriate surgical approaches to achieve the maximum safe resection of the tumor around the impaired optic nerve, and (3) employing the additional approach under making it difficult to achieve the enough resection by single surgical approach. We review our treatment experience with the above surgical strategy for the skull base tumors invading OCs with acute visual impairment, and discuss surgical approaches and patient outcomes.

Methods: We surgically treated 5 patients (one each of atypical meningioma, adenoid cystic carcinoma, Ewing PNET, chordoma, and schwannoma) presenting with acute visual impairment, accompanying with large extension into OCs and orbit. First, as early as possible, to rescue the visual function transbasal approach was performed for surgical resection of these tumors in all cases. The affected OCs were routinely opened. Subsequently infratemporal fossa approach or Dolenc approach were additionally given for the radical resection of tumors with wide lateral extension.

Results: The transbasal approach through the anterior midline skull base was efficacious in removing the tumors around the OCs and orbit, as well as sphenoid sinus, ethmoid sinus, nasal cavity, clivus and parapharyngeal space. With early treatment in this fashion, 4 out of 5 patients showed remarkable improvement of visual acuity and visual field defects without serious surgical complications. But via transbasal approach, there were the blind areas to extirpate the tumors in inferolateral extension in the orbit and the lateral aspects of maxillary sinus. Hence for 4 cases, the lateral approach like infratemporal fossa approach or Dolenc approach was additionally required. With this surgical strategy gross total removal was achieved in 3 out of 5 patients.

Conclusion: The tumor resection via transbasal approach can be a safe and effective treatment to rescue the visual function for the skull base and craniofacial tumors extending into OCs and orbit presenting with acute visual impairment.