Focal Resection

By: Andrew Yee

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What is Focal Resection?

Focal Resection is a type of surgery that removes (resects) the tissue from the brain that causes focal seizures. Focal Resection usually removes parts of the temporal lobe in hopes of stopping seizures, or, at a minimum, lowering the frequency. The whole lobe/tissue of the brain is not generally removed during surgery, but instead, small parts of the brain where the seizures are centered (Focal Cortical (Brain) Resection).

Who is Eligible?

Surgery is considered the best option for people who suffer from seizures and have not seen improvement in these seizures after taking at least two medications. These are drug-resistant seizures, and surgery is recommended if no progress is made after a year or two of trying medications. People who suffer from drop attacks, also known as atonic seizures, focal seizures, brain tumors, or even blood vessel complications, can also qualify for Focal Resection (UCSF Health, 2022).

Identifying the Location of Seizures

Doctors can use a variety of methods to determine the location of seizures, including:

  • Electroencephalogram (EEG): Electrodes are placed onto the patient’s scalp, and electrical signals are converted into patterns showing the regions active during seizures (Electroencephalogram (EEG), 2021).
  • Magnetic Resonance Imaging (MRI): Magnetic fields form around the patient as magnetic waves are released, showing the alignment of protons and capturing the energy released to create an image (UCSF Health, 2022).
  • Positron Emission Tomography (PET): A PET will measure your tissues and organs metabolic rates and identify any disturbances/abnormalities (PET/CT scan, 2021).
  • Single Photon Emission Computerized Tomography (SPECT): A radioactive compound is injected into the patient’s bloodstream, where scans of seizure activity in the brain are compared to scans of regular brain activity to identify the region causing strokes (UCSF Health, 2022).
  • Magnetoencephalography (MEG): Children under seven will undergo anesthesia, with electrons on their scalp. The machine will then measure the magnetic fields generated by the patient’s brain neurons and any electrical disturbances to determine the location of the seizures (Magnetoencephalography, 2014).
  • Stereoelectroencephalography (SEEG): If the location of seizures is still inconclusive, intracranial monitoring will occur. Like an EEG and a MEG, the patient’s brain activity will be monitored by electrodes placed in or on the scalp. They will either have intracranial monitoring or an SEEG (a less intrusive version of intracranial monitoring) but will require the patient to be hospitalized a week before the surgery (UCSF Health, 2022).


Mental tests will be given to the patient to further determine the location of the patient’s seizures and their affected parts. These tests will include memory, language, and comprehension skills, the most notable being a Wada test.

A Wada test will have the left and right hemispheres sedated at different times to determine which side of the brain is primarily responsible for specific functions like speech and memory (UCSF Health, 2022).


A neurosurgeon will start by cutting the scalp open and removing a piece of the skull. The dura will then be pulled back, and the surgeon will make their way to the focal point of the patient’s seizures using specialized navigation tools. Surgeons may require more help identifying the focal point of attacks during the surgery and will stimulate various parts of the brain during the surgery- this is painless. Once the focal point is removed, the surgeon will replace the dura and the piece of bone removed (Focal Cortical Resection).


The patient will remain in the hospital on the night of the surgery. The following day they will be able to walk and eat, but pain medications will be administered through the veins for a couple of days until oral medicines suffice. The patient will remain in the hospital for three to four days following the surgery.

Side Effects Include:

Swelling and bruising of the scalp


Feeling “out of it”

Difficulty remembering things



Focal Resection removes the focal point of the seizures in the patient’s brain. By removing the focal point, the seizures should subside or happen less often. Before the surgery, the patient will receive tests that gauge the brain and how it functions to determine the surgical approach. After the surgery, you will be hospitalized for a few days and usually experience cognitive side effects. However, these side effects should resolve themselves within six weeks alongside your seizures, making Focal Resection an optimal choice for those with epilepsy hoping to get relief.


Children’s Hospital of Philadelphia (2022). Magnetoencephalography (MEG Scan). Children’s Hospital of Philadelphia. Retrieved from:

John Hopkins Medicine (2021). Electroencephalogram (EEG). John Hopkins Medicine. Retrieved January 7, 2023 from

Texas Children’s Hospital (2022). Focal Cortical Resection. Texas Children’s Hospital. Retrieved from:

UCSF Department of Radiology and Biomedical Imaging (2022). PET/CT Scan. UCSF Department of Radiology and Biomedical Imaging. Retrieved from:

UCSF Health (2022). Focal Resection. UCSF Health. Retrieved from:

UPMC Children’s Hospital of Pittsburgh (2022). Childhood Seizure Treatment: focal Cortical (Brain) Resection. UPMC Children’s Hospital of Pittsburgh. Retrieved from:

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