What is an amygdalohippocampectomy?
An amygdalohippocampectomy is a surgical operation to remove a portion of the brain as a treatment for temporal lobe epilepsy.
An amygdalohippocampectomy is a surgical operation to remove a portion of the brain as a treatment for temporal lobe epilepsy. The procedure involves the selective removal of certain portions of the brain’s temporal lobe. The temporal lobes are located beneath the temples on either side of the head.
Temporal lobe epilepsy is the most common form of epileptic seizures that originate from a single point (focal epilepsy) in the brain. A majority of temporal lobe epileptic seizures originate in the medial part of the temporal lobe.
The traditional approach of surgical treatment for temporal lobe epilepsy was removal of the entire anterior portion of the temporal lobe (anterior temporal lobectomy). A selective amygdalohippocampectomy spares the unaffected portion of the anterior temporal lobe.
In a selective amygdalohippocampectomy, the following portions of the medial temporal lobe are removed:
- Amygdala: Processes and recalls emotional responses such as fear, anger and anxiety.
- Hippocampus: Helps form new memories and regulates motivation, memory, emotion, and learning.
- Parahippocampal gyrus: Surrounds the hippocampus and plays a role in spatial memory and navigation.
Why is an amygdalohippocampectomy performed?
An amygdalohippocampectomy is performed only for treatment of the type of epileptic seizures that
- Originate from the temporal lobe’s medial part
- Do not respond to medical therapy
- The surgery may be performed if imaging tests of the temporal medial region reveal
- Abnormality in the tissue
- Degeneration of the hippocampus
- Lesions or tumors
- Neurodevelopmental abnormality
An amygdalohippocampectomy is not performed for:
- Nonepileptic seizures
- Generalized seizures of unknown cause (idiopathic)
- Seizures originating in lobes other than the temporal lobe
- Independent epilepsy onset in both the temporal lobes
- Impairment of verbal, visual and spatial memory
- Temporal lobe seizures without clear indication of the medial region’s involvement
How is an amygdalohippocampectomy performed?
An amygdalohippocampectomy is a major surgery involving a vital organ. A neurosurgeon performs the procedure using general anesthesia. The procedure may require a hospital stay of up to four days.
Amygdalohippocampectomy is performed after the patient undergoes several tests to be certain of the origin and cause of the seizures and the fitness of the patient for surgery. The tests include:
- Blood and urine tests
- Neuropsychological examination of global, verbal and visual memory quotient
- Imaging tests such as
- Magnetic Resonance Imaging (MRI)
- Video Electroencephalogram (EEG)
- Positron-Emission Tomography (PET)
- Magnetoencephalography (MEG)
- Ictal Single-Photon Emission Computed Tomography (SPECT)
- Prior to the procedure, the patient must
- Avoid eating or drinking for eight hours.
- Check with the doctor before taking any regular medications.
- Inform the doctor of any allergies.
- Attaches an IV line and administers general anesthesia.
- Intubates the patient to assist breathing.
- Monitors the patient’s vital signs during the procedure.
- The patient lies flat with their face turned to one side and their head fixed with a frame to prevent movement during the procedure.
- Uses neuronavigational guidance for the procedure.
- Administers local anesthesia in the temporal scalp.
- Makes an incision in the scalp and retracts from the skull.
- Makes an opening in the skull (craniotomy).
- Opens and retracts the brain’s membrane (dura mater).
- Locates and excises (resects) the amygdala, hippocampus and parahippocampal gyrus.
- Checks the cranial cavity and arrests any bleeding.
- Closes the dura mater with sutures and applies a surgical glue to prevent leakage of cerebrospinal fluid (CSF).
- Replaces the bone flap using surgical glue and a plate for reinforcement.
- Closes the incision with absorbable sutures.
- Is weaned off anesthesia and administered painkillers.
- Is monitored in the neurological ICU during recovery.
- Undergoes a CT scan and neurological examination that is compared with the preoperative test.
- Continues taking antiepileptic drugs.
What are the risks and complications of an amygdalohippocampectomy?
Amygdalohippocampectomy is an effective surgery for drug-resistant epileptic seizures. The potential complications include:
- Injury to blood vessels and hemorrhaging
- Vascular spasm
- Wound infection
- Tissue death (infarction) due to lack of blood supply
- Inaccurate or incomplete resection
- Vision problems
- Memory impairment
- Transient difficulty with recall of words and names (transient dysnomia)
- Mood changes
- Recurrence of seizures