Epilepsy surgery

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Epilepsy surgery
Specialty neurology, neurosurgery, epileptology

Epilepsy surgery involves a neurosurgical procedure where an area of the brain involved in seizures is either resected, ablated, disconnected or stimulated. [1] The goal is to eliminate seizures or significantly reduce seizure burden. Approximately 60% of all people with epilepsy (0.4% of the population of industrialized countries) have focal epilepsy syndromes. In 15% to 20% of these patients, the condition is not adequately controlled with anticonvulsive drugs. Such patients are potential candidates for surgical epilepsy treatment.

Contents

First line therapy for epilepsy involves treatment with anticonvulsive drugs, also called antiepileptic drugs. Most patients will respond to one or two different medication trials. The goal of this treatment is the elimination of seizures, since uncontrolled seizures carry significant risks, including injury and sudden death. However, in up to one third of patients, medications alone do not eliminate seizures, and/or cause adverse effects. In these patients, epilepsy surgery is considered as an alternate treatment method to medications.

Generally, surgery is considered in patients whose seizures cannot be controlled by adequate trials of two different medications. Epilepsy surgery has been performed for more than a century, but its use dramatically increased in the 1980s and 1990s, reflecting its efficacy in selected patients. [2] [3]

Evaluation

The evaluation for epilepsy surgery is designed to locate the "epileptic focus" (the location of the epileptic abnormality) and to determine if resective surgery will affect normal brain function. The definition of the epileptogenic zone has a fundamental role in determining the boundaries of the area that needs to be removed in order to achieve seizure freedom but also in order not to harm “eloquent cortex” (damage to this area produces neurological deficit). As the localization technology has improved, the definition of the epileptogenic zone has expanded to comprise a larger area of the brain than before. [4] Resective surgery involves the resection, or cutting away, of brain tissue from the area of the brain that consists of the epileptic focus. Physicians will also confirm the diagnosis of epilepsy to make sure that spells arise from epilepsy (as opposed to non-epileptic seizures). The evaluation typically includes neurological examination, routine EEG, Long-term video-EEG monitoring, neuropsychological evaluation, and neuroimaging such as MRI, single photon emission computed tomography (SPECT), positron emission tomography (PET). Some epilepsy centers use intracarotid sodium amobarbital test (Wada test), functional MRI (fMRI) or magnetoencephalography (MEG) as supplementary tests. [5] Recently it has been suggested that computer models of seizure generation may provide valuable additional information regarding the source of seizures. [6]

If noninvasive testing was inadequate in identifying the epileptic focus or in distinguishing the surgical target from normal brain tissue and function, then Long-term video-EEG monitoring with the use of intracranial electrodes may be required for evaluation. Brain mapping by the technique of cortical electrical stimulation or Electrocorticography are other procedures used in the process of invasive testing for certain patients. [7] [8]

Once the epilepsy focus is located, the specific surgery involved in treatment is decided on. The type of surgery depends on the location of the seizure focal point. Surgeries for epilepsy treatment include, but are not limited to, the following types: temporal lobe resection, hemispherectomy, ground temporal and extratemporal resection, parietal resection, occipital resection, frontal resection, extratemporal resection, and callosotomy. [9] [10] [11]

Hemispherectomy

Hemispherectomy or hemispherotomy involves removal or a functional disconnection of most, or all of, one half of the brain typically leaving the basal ganglia and thalamus. It is reserved for people with the most catastrophic epilepsies, such as those due to Rasmussen's encephalitis. If the surgery is performed on very young patients (2–5 years old), then the remaining hemisphere may acquire some motor control of the ipsilateral body due to neuroplasticity; in older patients, paralysis results on the side of the body opposite to the part of the brain that was removed with less prospect for recovery. A visual field defect is an unavoidable side effect, typically involving a homonymous hemianopia involving loss of the half of the visual field on the same side of the disconnected brain. Because of these and other side-effects, it is usually reserved for patients having exhausted other treatment options. [12]

Temporal lobe resection

Temporal lobe resection acts as a treatment option for patients with temporal lobe epilepsy, or those whose seizure focus is in the temporal lobe. Temporal lobe seizures are the most common type of seizures for teens and young adults. The procedure involves resecting, or cutting away, brain tissue within the region of the temporal lobe in order to remove the seizure focus. Specific evaluation for temporal lobe resection requires convergent clinical, MRI, and EEG data in order to precisely pinpoint the focal area and boundaries of the focal area. [13]

The surgery has produced successful outcomes, controlling seizures in 65 percent of temporal lobe epilepsy patients. Follow-up studies suggest that the procedure also has produced positive long-term effects that illustrate 63 percent of patients still remaining seizure-free. [14] Although the procedure produces positive outcomes for patients regarding seizure control, the surgery can also produce negative outcomes such as memory impairment. Impairment depends on the hemisphere of resection; temporal lobe resection of the dominant hemisphere often causes verbal memory impairment while temporal lobe resection of the non-dominant hemisphere often causes visual memory impairment. [15]

Extratemporal lobe resection

Extratemporal lobe resection acts as a treatment option for patients with extratemporal epilepsy, or epilepsy patients whose seizure focus is outside of the temporal lobe, and stems from either the occipital lobes, parietal lobe, frontal lobe, or in multiple lobes. [16] The evaluation for the procedure often requires more than clinical, MRI, and EEG convergence due to the variability of the seizure focus. Along with additional imaging techniques such as PET and SPECT, invasive studies may be needed to pinpoint the seizure focus. The efficacy of extratemporal lobe resection generally is less than resection of the temporal lobe. For example, in frontal lobe resections seizure freedom has been achieved in 38-44 percent of patients. [17]

Tumor Resection

If a benign or malignant brain tumor is suspected to be the cause of seizure activity, surgical removal of the tumor may be indicated. The approach and technique is case-dependent. One study of supratentorial brain tumors in children less observed a dramatic reduction in the severity and frequency of seizures at one and four year follow-up. [18]

Laser Ablation

See ablative brain surgery . [19]

See also

Related Research Articles

Hemispherectomy is a surgery that is performed by a neurosurgeon where an unhealthy hemisphere of the brain is disconnected or removed. There are two types of hemispherectomy. Functionalhemispherectomy refers to when the diseased brain is simply disconnected so that it can no longer send signals to the rest of the brain and body. Anatomical hemispherectomy refers to when not only is there disconnection, but also the diseased brain is physically removed from the skull. This surgery is mostly used as a treatment for medically intractable epilepsy, which is the term used when anti-seizure medications are unable to control seizures.

<span class="mw-page-title-main">Aura (symptom)</span> Symptom of epilepsy and migraine

An aura is a perceptual disturbance experienced by some with epilepsy or migraine. An epileptic aura is a seizure.

Long-term or "continuous" video-electroencephalography (EEG) monitoring is a diagnostic technique commonly used in patients with epilepsy. It involves the long-term hospitalization of the patient, typically for days or weeks, during which brain waves are recorded via EEG and physical actions are continuously monitored by video. In epileptic patients, this technique is typically used to capture brain activity during seizures. The information gathered can be used for initial prognosis or long-term care management.

<span class="mw-page-title-main">Temporal lobe epilepsy</span> Chronic focal seizure disorder

In the field of neurology, temporal lobe epilepsy is an enduring brain disorder that causes unprovoked seizures from the temporal lobe. Temporal lobe epilepsy is the most common type of focal onset epilepsy among adults. Seizure symptoms and behavior distinguish seizures arising from the medial temporal lobe from seizures arising from the lateral (neocortical) temporal lobe. Memory and psychiatric comorbidities may occur. Diagnosis relies on electroencephalographic (EEG) and neuroimaging studies. Anticonvulsant medications, epilepsy surgery and dietary treatments may improve seizure control.

Frontal lobe epilepsy (FLE) is a neurological disorder that is characterized by brief, recurring seizures arising in the frontal lobes of the brain, that often occur during sleep. It is the second most common type of epilepsy after temporal lobe epilepsy (TLE), and is related to the temporal form in that both forms are characterized by partial (focal) seizures.

<span class="mw-page-title-main">Electrocorticography</span> Type of electrophysiological monitoring

Electrocorticography (ECoG), a type of intracranial electroencephalography (iEEG), is a type of electrophysiological monitoring that uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex. In contrast, conventional electroencephalography (EEG) electrodes monitor this activity from outside the skull. ECoG may be performed either in the operating room during surgery or outside of surgery. Because a craniotomy is required to implant the electrode grid, ECoG is an invasive procedure.

Anterior temporal lobectomy (ATL) is the complete or partial removal of the anterior portion of the temporal lobe of the brain. The exact boundaries for removal can vary slightly in practice and between neurosurgeons. It is a treatment option for temporal lobe epilepsy for those in whom anticonvulsant medications do not control epileptic seizures, and who have frequent seizures, and who additionally qualify based on a WADA test to localize the dominant hemisphere for language module.

In the field of neurology, seizure types are categories of seizures defined by seizure behavior, symptoms, and diagnostic tests. The International League Against Epilepsy (ILAE) 2017 classification of seizures is the internationally recognized standard for identifying seizure types. The ILAE 2017 classification of seizures is a revision of the prior ILAE 1981 classification of seizures. Distinguishing between seizure types is important since different types of seizures may have different causes, outcomes, and treatments.

<span class="mw-page-title-main">Dysembryoplastic neuroepithelial tumour</span> Medical condition

Dysembryoplastic neuroepithelial tumour is a type of brain tumor. Most commonly found in the temporal lobe, DNTs have been classified as benign tumours. These are glioneuronal tumours comprising both glial and neuron cells and often have ties to focal cortical dysplasia.

<span class="mw-page-title-main">Amygdalohippocampectomy</span>

Amygdalohippocampectomy is a surgical procedure for the treatment of epilepsy. It consists of the removal of the hippocampus, which has a role in memory, spatial awareness, and navigation, and the amygdalae, which have a role in the processing and memory of emotional reactions, both structures forming part of the limbic system of the brain.

Post-traumatic epilepsy (PTE) is a form of acquired epilepsy that results from brain damage caused by physical trauma to the brain. A person with PTE experiences repeated post-traumatic seizures more than a week after the initial injury. PTE is estimated to constitute 5% of all cases of epilepsy and over 20% of cases of acquired epilepsy.

<span class="mw-page-title-main">Epilepsy in children</span>

Epilepsy is a neurological condition of recurrent episodes of unprovoked epileptic seizures. A seizure is an abnormal neuronal brain activity that can cause intellectual, emotional, and social consequences. Epilepsy affects children and adults of all ages and races, it is one of the most common neurological disorders of the nervous system. As well as, this condition is more common among children than adults affecting about 6 out of 1000 US children that are between the age of 0 to 5 years old. The epileptic seizures can be of different types depending on the part of the brain that was affected, seizures are classified in 2 main types partial seizure or genralized seizure.

Cortical stimulation mapping (CSM) is a type of electrocorticography that involves a physically invasive procedure and aims to localize the function of specific brain regions through direct electrical stimulation of the cerebral cortex. It remains one of the earliest methods of analyzing the brain and has allowed researchers to study the relationship between cortical structure and systemic function. Cortical stimulation mapping is used for a number of clinical and therapeutic applications, and remains the preferred method for the pre-surgical mapping of the motor cortex and language areas to prevent unnecessary functional damage. There are also some clinical applications for cortical stimulation mapping, such as the treatment of epilepsy.

People with epilepsy may be classified into different syndromes based on specific clinical features. These features include the age at which seizures begin, the seizure types, and EEG findings, among others. Identifying an epilepsy syndrome is useful as it helps determine the underlying causes as well as deciding what anti-seizure medication should be tried. Epilepsy syndromes are more commonly diagnosed in infants and children. Some examples of epilepsy syndromes include benign rolandic epilepsy, childhood absence epilepsy and juvenile myoclonic epilepsy. Severe syndromes with diffuse brain dysfunction caused, at least partly, by some aspect of epilepsy, are also referred to as epileptic encephalopathies. These are associated with frequent seizures that are resistant to treatment and severe cognitive dysfunction, for instance Lennox-Gastaut syndrome and West syndrome.

Drug-resistant epilepsy (DRE), also known as refractory epilepsy, intractable epilepsy, or pharmacoresistant epilepsy, is diagnosed following a failure of adequate trials of two tolerated and appropriately chosen and used antiepileptic drugs (AEDs) to achieve sustained seizure freedom. The probability that the next medication will achieve seizure freedom drops with every failed AED. For example, after two failed AEDs, the probability that the third will achieve seizure freedom is around 4%. Drug-resistant epilepsy is commonly diagnosed after several years of uncontrolled seizures, however, in most cases, it is evident much earlier. Approximately 30% of people with epilepsy have a drug-resistant form.

<span class="mw-page-title-main">Occipital epilepsy</span> Medical condition

Occipital epilepsy is a neurological disorder that arises from excessive neural activity in the occipital lobe of the brain that may or may not be symptomatic. Occipital lobe epilepsy is fairly rare, and may sometimes be misdiagnosed as migraine when symptomatic. Epileptic seizures are the result of synchronized neural activity that is excessive, and may stem from a failure of inhibitory neurons to regulate properly.

Musicogenic epilepsy is a form of reflex epilepsy with seizures elicited by special stimuli.

<span class="mw-page-title-main">Fabrice Bartolomei</span> French neurophysiologist

Fabrice Bartolomei is a French neurophysiologist, and University Professor at Aix-Marseille University (AMU), leading the Service de Neurophysiologie Clinique of the Timone Hospital at the Assistance Publique - Hôpitaux de Marseille, and he is the medical director of the ‘Centre Saint-Paul - Hopital Henri Gastaut’. He is the coordinator of the clinical network CINAPSE that is dedicated to the management of adult and pediatric cases of severe epilepsies and leader of the Federation Hospitalo-Universitaire Epinext. He is also member of the research unit Institut de Neurosciences des Systèmes](INS), UMR1106, Inserm - AMU.

Musicogenic seizure, also known as music-induced seizure, is a rare type of seizure, with an estimated prevalence of 1 in 10,000,000 individuals, that arises from disorganized or abnormal brain electrical activity when a person hears or is exposed to a specific type of sound or musical stimuli. There are challenges when diagnosing a music-induced seizure due to the broad scope of triggers, and time delay between a stimulus and seizure. In addition, the causes of musicogenic seizures are not well-established as solely limited cases and research have been discovered and conducted respectively. Nevertheless, the current understanding of the mechanism behind musicogenic seizure is that music triggers the part of the brain that is responsible for evoking an emotion associated with that music. Dysfunction in this system leads to an abnormal release of dopamine, eventually inducing seizure.

<span class="mw-page-title-main">Elaine Wyllie</span> American neurologist

Elaine Wyllie is a professor of neurology at the Cleveland Clinic Lerner College of Medicine and staff physician in Cleveland Clinic's Epilepsy Center. Her research focuses on the role of epilepsy surgery in children with drug-resistant seizures.

References

  1. ↑ Jobst BC, Cascino GD (2015). "Resective epilepsy surgery for drug-resistant focal epilepsy: a review". JAMA. 313 (3): 285–93. doi:10.1001/jama.2014.17426. PMID   25602999.
  2. ↑ Spencer SS, Berg AT, Vickrey BG, et al. (December 2003). "Initial outcomes in the Multicenter Study of Epilepsy Surgery". Neurology. 61 (12): 1680–5. doi:10.1212/01.WNL.0000098937.35486.A3. PMID   14694029. S2CID   21481756.
  3. ↑ Krucoff, Max O.; Chan, Alvin Y.; Harward, Stephen C.; Rahimpour, Shervin; Rolston, John D.; Muh, Carrie; Englot, Dario J. (December 2017). "Rates and predictors of success and failure in repeat epilepsy surgery: A meta-analysis and systematic review". Epilepsia. 58 (12): 2133–2142. doi:10.1111/epi.13920. ISSN   1528-1167. PMC   5716856 . PMID   28994113.
  4. ↑ Jehi, Lara (January 2018). "The Epileptogenic Zone: Concept and Definition". Epilepsy Currents. 18 (1): 12–16. doi:10.5698/1535-7597.18.1.12. ISSN   1535-7597. PMC   5963498 . PMID   29844752.
  5. ↑ Rosenow, Felix; Luders, Hans (2001). "Presurgical evaluation of epilepsy". Brain. 124 (9): 1683–1700. doi: 10.1093/brain/124.9.1683 . PMID   11522572.
  6. ↑ Goodfellow, Marc (2016). "Estimation of brain network ictogenicity predicts outcome from epilepsy surgery". Scientific Reports. 6: 29215. Bibcode:2016NatSR...629215G. doi:10.1038/srep29215. PMC   4935897 . PMID   27384316.
  7. ↑ Nakai, Y; Jeong, JW; Brown, EC; Rothermel, R; Kojima, K; Kambara, T; Shah, A; Mittal, S; Sood, S; Asano, E (2017). "Three- and four-dimensional mapping of speech and language in patients with epilepsy". Brain. 140 (5): 1351–1370. doi:10.1093/brain/awx051. PMC   5405238 . PMID   28334963.
  8. ↑ Nakai, Y; Nagashima, A; Hayakawa, A; Osuki, T; Jeong, JW; Sugiura, A; Brown, EC; Asano, E (2018). "Four-dimensional map of the human early visual system". Clin Neurophysiol. 129 (1): 188–197. doi:10.1016/j.clinph.2017.10.019. PMC   5743586 . PMID   29190524.
  9. ↑ Chugani, HT; Ilyas, M; Kumar, A; Juhász, C; Kupsky, WJ; Sood, S; Asano, E (2015). "Surgical treatment for refractory epileptic spasms: The Detroit series". Epilepsia. 56 (12): 1941–9. doi:10.1111/epi.13221. PMC   4679547 . PMID   26522016.
  10. ↑ Chugani, HT; Asano, E; Juhász, C; Kumar, A; Kupsky, WJ; Sood, S (2014). ""Subtotal" hemispherectomy in children with intractable focal epilepsy" (PDF). Epilepsia. 55 (12): 1926–33. doi: 10.1111/epi.12845 . hdl:2027.42/109835. PMID   25366422.
  11. ↑ Tellez-Zenteno, Jose F.; Dhar, Raj; Samuel, Wiebe (2005). "Long-term seizure outcomes following epilepsy surgery: a systematic review and meta-analysis". Brain. 128 (5): 1188–1198. doi: 10.1093/brain/awh449 . PMID   15758038.
  12. ↑ Lettori, D.; Battaglia, A.; Sacco, A.; Veredice, C.; Chieffo, D.; Massimi, L.; Tartaglione, T.; Chiricozzi, F.; Staccioli, S.; Mittica, A.; Di Rocco, C.; Guzzetta, F. (2008). "Early hemispherectomy in catastrophic epilepsy". Seizure. 17 (1): 49–63. doi: 10.1016/j.seizure.2007.06.006 . PMID   17689988.
  13. ↑ Noachtar, Soheyl; Borggraefe, Ingo (May 2009). "Epilepsy surgery: A critical review". Epilepsy & Behavior. 15 (1): 66–72. doi:10.1016/j.yebeh.2009.02.028. PMID   19236942. S2CID   33364764.
  14. ↑ Tellez-Zenteno, Jose F.; Dhar, Raj; Samuel, Wiebe (2005). "Long-term seizure outcomes following epilepsy surgery: a systematic review and meta-analysis". Brain. 128 (5): 1188–1198. doi: 10.1093/brain/awh449 . PMID   15758038.
  15. ↑ Bonelli, Silvia B.; et al. (2013). "Memory reorganization following anterior temporal lobe resection: a longitudinal functional MRI study". Brain. 136 (6): 1889–1900. doi:10.1093/brain/awt105. PMC   3673465 . PMID   23715092.
  16. ↑ "Epilepsy and Extratemporal Cortical Resection". WebMD. Retrieved 23 April 2015.
  17. ↑ Ryvlin, Philippe; Cross, J Helen; Rheims, Sylvain (November 2014). "Epilepsy surgery in children and adults". The Lancet Neurology. 13 (11): 1114–1126. doi:10.1016/S1474-4422(14)70156-5. PMID   25316018. S2CID   5400708.
  18. ↑ "Management of Infantile Epilepsies". effectivehealthcare.ahrq.gov. doi:10.23970/ahrqepccer252 . Retrieved 2024-03-18.
  19. ↑ "Laser Ablation Surgery for Epilepsy". Texas Children's Hospital. Archived from the original on 10 June 2012. Retrieved 8 October 2016.
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