Revisiting the Anatomy with Physics: A Preliminary, Single-Center Experience with Its Current Surgical Platform for the Treatment of Skull Base Meningiomas

Objective: In this study, the authors’ objectives are to describe and analyze their early clinical experience in the management of skull base meningiomas with a revised algorithm implementing a preoperative planning platform, intraoperative neuronavigation, and a robotically-guided optical system for visualization.

Methods: A series of 39 consecutive patients who presented with 42 skull base meningiomas were selected and retrospectively reviewed between April 2015 and November 2017. Preoperative, intraoperative, and postoperative data were retrieved from electronic medical records. The following outcomes were assessed: (1) clinical assessment of preoperative and postoperative cranial nerve function, (2) qualitative assessment of white matter tract preservation and recovery, and (3) measurement of FLAIR signal volume to determine extent of edema and brain retraction.

Results: The patient cohort comprised 2 (5%) males and 37 (95%) females with a mean age of 56 years ± 15. Ten (23%) procedures were performed via a ventral EEA corridor and 32 from a dorsal transcranial corridor. Three of these cases (olfactory groove meningiomas) were managed with a combined, staged approach using ventral EEA and dorsal transcranial corridors. All dorsal transcranial cases utilized a robotically guided optical system without conversion to a different optical modality. All cases in the EEA subgroup utilized a ventral anteromedial approach, which included the following: olfactory groove (1), tuberculum sella/subchiasmatic (3), and sphenocavernous (3). The dorsal transcranial approach had the following case distribution: medial sphenoid wing (4), anterior clinoid (1), sphenoorbital (4), lateral sphenoid wing (5), cerebellopontine angle (4), and tentorial (2). Cases performed in the dorsal anteromedial corridor were further analyzed, with the following distribution: planum/tuberculum prechiasmatic (7) and paramedian orbital roof (2). Within this subgroup, average tumor volume reduction was 82.0 ± 23.4 (range = 81.3–99.4). Functional cranial nerve recovery was 67%. There was an average FLAIR hyperintensity reduction of 50.8% ± 44.6 (range = −100 to 22), with only two patients experiencing an increase in FLAIR signal change. In addition, 6 out of the 8 (75%) patients who had pre- and postoperative DTI imaging demonstrated preservation or enhancement of IFO volume. In this series, there was one delayed CSF leak in the EEA subgroup, and one mortality and two postoperative complications in the dorsal subgroup. The authors believe that these events were not due to the surgical algorithm or technology used.

Conclusion: The authors’ early experience with their current surgical algorithm has lent them to revise the anatomic framework based on the technology employed. Given their preliminary results, a trend can be drawn to preferentially manage olfactory groove, paramedian orbital roof, and planum meningiomas solely via a dorsal transcranial route. Given the current anatomic limitations, subchiasmatic tuberculum sellae and sphenocavernous meningiomas, can currently remain an EEA approach.