**7.1 Positioning of the patient and general settings**

The patient is placed in a supine position with the head rotated 30° to the contralateral side and fixed in a three-pin Mayfield head-holder. The neck is slightly extended to 15°, as is done for a classical pterional approach. Neuronavigation is used to delineate the craniotomy and skin incision. We recommend using millimeter slices of the bone window of the CT scan for registration, to both highlight bone tumor extension and increase the accuracy of this technique [19, 20]. The CT scan is then merged with the MRI, including the gadolinium-enhanced 3D T1-weighted sequence, for intra- and extracranial tumor extensions (**Figure 4**). A paraumbilical field is prepared and draped to harvest abdominal fat for closure if needed.
