Brain and cranial surgery are all those techniques to treat the encephalic mass and annexed organs, which includes the cranial bony vault, the cranial nerves, the meninges and the pituitary gland.
What pathologies does cranial and brain surgery treat?
Cranial surgery in Neurosurgery treats various pathologies depending on the origin, severity and consequences in the patient, creating subspecialties:
- Neuro-oncological and tumor surgery. In this type of brain surgery, neoplasms of any origin and aggressiveness are treated. These may include primary tumors of the central nervous system (oligodendrogliomas, schwannomas or gliomas), metastases (satellite tumors of other pre-existing malignant tumors of any origin), tumors in the meninges, etc.
- Skull base surgery. It is the surgery that treats tumors at the base of the skull, a very complex structure with many nerve entrances and exits and blood vessels that are difficult to access. Hence, there are very specific techniques that overlap with other areas of functional neurosurgery, such as cranial nerve surgery.
- Neuroendocrinological surgery. It is an operation of the pituitary gland, located in an area bordering the nostrils and sinuses. It is a specific skull base surgery.
- Neurovascular surgery. It is focused on the treatment of congenital or acquired vascular malformations, such as aneurysms and cavernomas, or arteriovenous malformations (AVM).
- Craniocervical junction surgery. It is indicated for malformations that produce high vertebral instability or compression of the medulla or cerebellum (Arnold-Chiari malformation, for example).
- Surgery to evacuate cerebrospinal fluid (CSF). It is indicated in congenital or acquired alterations that may cause problems in the normal circulation of cerebrospinal fluid, especially in its reabsorption, accumulating too much inside the brain (which produces hydrocephalus), also creating endocranial hypertension. This will require surgical techniques to facilitate evacuation.
- Functional neurosurgery. These are treatments focused on the control of neuropathic pain or neuralgia of the cranial nerves, such as the trigeminal nerve. They are also performed for the treatment of diseases such as Parkinson’s disease, through the implantation of neurostimulators.
- Traumatic neurosurgery. It is aimed at evacuating intracranial and/or intracerebral hematomas, cranial fractures or cerebral edema of traumatic origin.
- Reconstructive neurosurgery. When, due to trauma or excision of a cranial tumor, there is a significant cosmetic defect in the cranial vault, reconstructions can be performed with custom-made implants.
- I would only add in the section on Functional, which also includes surgeries performed for the treatment of diseases such as Parkinson’s, which are treated by implanting neurostimulators.
What does cranial and brain surgery consist of?
In order to perform brain surgery, it is usually necessary to open the cranial bone in order to access the pathology. This can be achieved with a simple hole in the bone (called a trephine) or by making a window in the bone and lifting the fragment, which will be repositioned at the end of the surgery (craniotomy) or not (craniectomy), depending on the patient’s needs and pathology.
With the simple trephine technique, some cerebral and subdural (skull bone) hematomas can be evacuated, and catheters can be placed to evacuate cerebrospinal fluid and treat hydrocephalus, and even biopsy intracerebral tumors.
If the specialist needs more control, a craniotomy is performed. Once the bone has been lifted, the dura mater, the thickest membrane covering the brain (meninges), is found, which must also be opened to access the brain tissue.
In pathologies such as Arnold-Chiari malformation, this procedure will have already achieved decompression. In tumors and vascular lesions the objective will be complete or partial excision, depending on the anatomical structures involved and the degree of malignancy, if it is a tumor. In cerebral aneurysms we will try to place a small clip to strangle them, avoiding rupture and bleeding, and returning the normal blood flow.
What cutting-edge technology and techniques are currently available?
There are tools that currently help to perform these surgeries with greater safety and precision:
- Neuronavigation allows, based on the patient’s imaging tests and anatomical references, to locate lesions precisely, adjusting the size and location of craniotomies and planning the surgery before performing it.
- The surgical microscope provides a better view of small, yet fragile structures. Also, contrast and fluorescence techniques with compounds such as 5-ALA are sometimes used with the microscope, allowing malignant neoplasms to be identified and resected.
- Intraoperative cerebral ultrasound allows tumors to be located in real time.
- Cerebral endoscopy allows access to deep and inaccessible locations.
- Intraoperative neurophysiological monitoring, which is commonly used in brain surgery, allows the neurophysiologist to monitor in real time the patient’s brain activity and the structures at possible risk. In this way, the surgeon and anesthesiologist can have greater knowledge of what is happening during surgery, detecting anomalies and dangerous processes before any neurological sequelae occur.
What will recovery and rehabilitation be like after brain surgery?
With the exception of minor skull or trephine openings, after surgery the patient is transferred to the ICU for neurological, hemodynamic and respiratory monitoring. If the patient evolves correctly, after 12-24 hours the patient will be transferred to conventional hospitalization, so that he/she can start moving with help and begin physiotherapy exercises.
The patient’s admission will depend on the autonomy he/she acquires to carry out daily activities, which can vary from a single night (normally cases of ventriculo-peritoneal shunt surgery) to a week (tumors with great neurological involvement).
In addition, if after surgery patients suffer strength deficits in the extremities, gait disturbance or imbalance, they can follow a rehabilitation plan until they achieve the maximum possible functionality. A patient without significant neurological deficit, who does not require additional treatments (chemotherapy or radiotherapy), could return to normal life in 6-8 weeks.
Are there any risks involved in brain surgery?
In general, any cranial surgery can be complicated by major intracranial hemorrhage in the first 48 hours. However, the frequency is 1% of cases. On the other hand, 2% of cases will suffer from surgical wound infection.
In addition, each pathology and location has a specific type of neurological risk, which can result in functional alterations and different degrees of severity. In any case, the risk estimation will be made on an individual patient basis, and the specialist will inform the patient before surgery.