Introduction of a New Functional Score for Skull Base Pathology

Introduction and Objective: To propose a grading system for skull base pathology that reflects the functional impact of cranial nerve and neurological deficits.

Material and Method: A scoring system was defined based on clinical cranial nerve function and neurological status. The cranial nerves were grouped into functional units. To these units a maximum numeric score was administered taking into account the functional impact. This clinical scoring system can be translated into a grading system for cranial base pathology. The grading system was applied to a clinical series of patients with skull base meningiomas.

Results: The grading system was validated by comparison with the Karnofsky Performance Score, which is the gold standard in the follow-up of a series of patients with petroclival meningioma. We found a positive correlation but with an additional fine-tuning of functional disability.

Conclusion: Current functional grading systems do not reflect the impact of cranial base pathology. The proposed cranial base grading system permits a pathology-specific functional classification that allows comparisons among the various clinical studies dealing with skull base pathology.