Frontolateral Keyhole Approach or Endonasal Approach in Case of Anterior Skull Base Meningiomas: Which Approach Should Be Preferred?

Objective: Keyhole approaches for the skull base are currently under investigation for skull base tumor surgery. A lower complication rate is to be expected with the same successful resection rate in comparison to endoscopic extended endonasal procedures, which promise to avoid retraction of neurovascular structures. However, the reported results with these techniques are diverging. Here, the authors compare their current series in case of anterior skull base meningiomas resected via an endoscopic endonasal or microsurgical frontolateral keyhole approach.

Methods: Between January 2011 and September 2015, a total of 14 patients received microsurgical frontolateral keyhole procedures for tuberculum sellae meningiomas and 10 patients for olfactorius meningiomas. In the same time period, three patients received endoscopic endonasal procedure for tuberculum sellae meningiomas and two patients for olfactorius meningiomas. The cases were prospectively followed (8 months to 3.6 years). The surgical technique was carefully analyzed and the endoscopic endonasal technique was compared with microsurgical supraorbital technique. Special attention was paid to necessity to switch the operation strategy, complications, surgical radicality, and recurrences.

Results: In all cases a sufficient visualization of the tumor was possible. In 9 of 14 microsurgical cases, an endoscope was used for final additional control of tumor resection. In all microsurgical and endoscopic cases a resection Simpson grade 1 was performed and in postoperative MRI follow-up no remaining tumor was visualized. There were no recurrences in follow-up. In one case of microsurgical procedure, an ischemia occurred in the frontal lobe without any neurological deficit. In endoscopic cases all patients received a lumbar drainage intraoperatively. No persistent CSF fistula occurred with this treatment.

Conclusion: Resection of skull base meningiomas via frontolateral keyhole approach has been shown to be safe and successful with a high radicality and only minor complications. Especially the high risk of CSF fistulas and the more sophisticated endonasal approach can be avoided. Thus, for most anterior skull base meningiomas, we usually prefer microsurgical transcranial (endoscopic assisted) approach. The use of lumbar drainage and autologous fat graft for skull base closure minimize the risk of CSF fistula.