gms | German Medical Science

Objective: Keyhole approaches and endonasal endoscopic approaches for the skull base are currently under investigation for 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 December 2016 18 patients received microsurgical frontolateral keyhole procedures for tuberculum sellae meningeomas and 11 patients for olfactorius meningiomas. In the same time period 6 patients received endoscopic endonasal procedure for tuberculum sellae meningiomas and 3 patients for olfactorius meningiomas. The cases were prospectively followed (4 months – 4.7 years). The surgical technique was carefully analysed and the endoscopic endonasal technique was compared to 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 24 of 29 microsurgical cases an endoscope was used for final additional control of tumor resection. Remnant tumour was visualized with angled optics in 28% of the endoscopic endonasal cases and in 56% of the microsurgical cases. Gross-total-resection was achieved in 77% of endonasal and 89% of transcranial cases. There were one recurrence 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 persistant 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 approach. Thereby, the application of angled endoscopes is an essential step of surgery resulting in a higher radicality of tumor resection. The use of lumbar drainage and autologous fat graft for skull base closure minimize the risk of CSF fistula.