1. Routine preoperative preparation.
The tumor is located at the base of the skull and is huge, and most of the patients are elderly, so preoperative preparation must be thorough. Blood tests, cardiac function, and lung function must be perfect, and the relevant departments should be consulted according to the results to adjust the patient's preoperative state to the bestAnother point is to communicate with the anesthesiology department in advance to assess the anesthesia risk to ensure the smooth progress of the operation.
2. Anesthesia. Giant anterior skull base meningioma has high intracranial pressure, abundant blood supply, and wide base, and the surgical risk is greater, and the anesthesia should be performed under moderate blood pressure to reduce bleedingThe anesthesiologist should also control the tidal volume and reduce the intracranial pressure as much as possible to facilitate the exposure and resection of the tumor.
3. Surgical approach and incision design.
a) Coronal incision, double frontal craniotomy, skull base approach.
This approach is required when the tumour is in the midline and the basal base is anteriorly up to the cockscomb. The bone window is a semicircular incision across the midline, as low as possible to the base of the nose, so that the base of the tumor can be viewed directly from front to back without the need to stretch the brain tissue, and then the dura is enlarged after decompression to remove the residual tumor.
2) The frontotemporal incision takes into account both the pterygoid point and the subfrontal craniotomy.
This method may be used when the tumor is located on one side, or when the tumor is located in the midline but the base is behind the cockscomb and the tumor is large. The bone window takes into account both the infrafrontal and pterygoid points, which facilitates the release of cerebrospinal fluid from the pterygoid points and reduces intracranial pressure on the one hand, and cuts off the tumor base through the subfrontal area on the other hand.
iii) Frontotemporal incision pterygotomy.
This method can be used when the tumor is on one side and near the lateral orbital plate. The pterygoid point releases cerebrospinal fluid, breaks the base of the tumor from the outside, and then removes the tumor in pieces.
iv) Frontotemporal incision with additional lateral craniotomy.
This method can be used when the tumor is located near the midline sphenoid plateau and sellar tubercles. The lateral aspect of the bony window does not need to open the pterygoid point, and the medial aspect of the bony window is about 2 cm from the midline, so that the damage is small and the frontal sinus can be avoided. During the operation, the frontal lobe can be lifted to release cerebrospinal fluid from the cistern of the internal carotid artery, and then the base can be cut off while the tumor is removed.