Anterior temporal lobectomy | |
---|---|
ICD-9-CM | 01.53 |
MeSH | D038481 |
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. [1] 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. [2]
The techniques for removing temporal lobe tissue vary from resection of large amounts of tissue, including lateral temporal cortex along with medial structures, from using more restricted ATL to more restricted removal of only the medial structures (selective amygdalohippocampectomy). [3] [4]
Nearly all reports of seizure outcome following these procedures indicate that the best outcome group includes patients with MRI evidence of mesial temporal sclerosis (hippocampal atrophy with increased T-2 signal). The range of seizure-free outcomes for these patients is reported to be between 80% and 90%, which is typically reported as a sub-set of data within a larger surgical series. [5] [6]
Open surgical procedures such as ATL have inherent risks including damage to the brain (either directly or indirectly by injury to important blood vessels), bleeding (which can require re-operation), blood loss (which can require transfusion), and infection. Furthermore, open procedures require several days of care in the hospital including at least one night in an intensive care unit. Although such treatment can be costly, multiple studies have demonstrated that ATL in patients who have failed at least two anticonvulsant drug trials (thereby meeting the criteria for medically intractable temporal lobe epilepsy) has lower mortality, lower morbidity and lower long-term cost in comparison with continued medical therapy without surgical intervention. [7]
The strongest evidence supporting ATL over continued medical therapy for medically refractory temporal lobe epilepsy is a prospective, randomized trial of ATL compared to best medical therapy (anticonvulsants), which convincingly demonstrated that the seizure-free rate after surgery was about 60% as compared to only 8% for the medicine only group. [8] Furthermore, there was no mortality in the surgery group, while there was seizure-related mortality in the medical therapy group. Therefore, ATL is considered the standard of care for patients with medically intractable mesial temporal lobe epilepsy. [9]
Recovery after ATL can take several weeks to months. Anti-seizure medications will be continued for several months after ATL. As it is an open surgery it takes time for the brain to heal. [10] Speech therapy, occupational therapy, etc. can help recovery. About 90% of people experience an improvement in seizures after temporal lobectomy. In mesial temporal lobe epilepsy, NAA (N-acetyl aspartate) has reduced concentration in epileptogenic hippocampus and contralateral hippocampus. In post-operative seizure free patients, NAA levels were significantly higher than post-operative non-seizure free patients and then returned to the normal level. [11]
ATL was popularised in the early 1980s and was found effective. [12]
Henry Gustav Molaison, known widely as H.M., was an American who had a bilateral medial temporal lobectomy to surgically resect the anterior two thirds of his hippocampi, parahippocampal cortices, entorhinal cortices, piriform cortices, and amygdalae in an attempt to cure his epilepsy. Although the surgery was partially successful in controlling his epilepsy, a severe side effect was that he became unable to form new memories.
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The Wada test, also known as the intracarotid sodium amobarbital procedure (ISAP), establishes cerebral language and memory representation of each hemisphere.
Corpus callosotomy is a palliative surgical procedure for the treatment of medically refractory epilepsy. In this procedure the corpus callosum is cut through in an effort to limit the spread of epileptic activity between the two halves of the brain.
Hippocampal sclerosis (HS) or mesial temporal sclerosis (MTS) is a neuropathological condition with severe neuronal cell loss and gliosis in the hippocampus. Neuroimaging tests such as magnetic resonance imaging (MRI) and positron emission tomography (PET) may identify individuals with hippocampal sclerosis. Hippocampal sclerosis occurs in 3 distinct settings: mesial temporal lobe epilepsy, adult neurodegenerative disease and acute brain injury.
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.
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.
Foix–Chavany–Marie Syndrome (FCMS), also known as bilateral opercular syndrome, is a neuropathological disorder characterized by paralysis of the facial, tongue, pharynx, and masticatory muscles of the mouth that aid in chewing. The disorder is primarily caused by thrombotic and embolic strokes, which cause a deficiency of oxygen in the brain. As a result, bilateral lesions may form in the junctions between the frontal lobe and temporal lobe, the parietal lobe and cortical lobe, or the subcortical region of the brain. FCMS may also arise from defects existing at birth that may be inherited or nonhereditary. Symptoms of FCMS can be present in a person of any age and it is diagnosed using automatic-voluntary dissociation assessment, psycholinguistic testing, neuropsychological testing, and brain scanning. Treatment for FCMS depends on the onset, as well as on the severity of symptoms, and it involves a multidisciplinary approach.
Epilepsy surgery involves a neurosurgical procedure where an area of the brain involved in seizures is either resected, ablated, disconnected or stimulated. The goal is to eliminate seizures or significantly reduce seizure burden. Approximately 60% of all people with epilepsy 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.
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.
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.
Transient epileptic amnesia (TEA) is a rare but probably underdiagnosed neurological condition which manifests as relatively brief and generally recurring episodes of amnesia caused by underlying temporal lobe epilepsy. Though descriptions of the condition are based on fewer than 100 cases published in the medical literature, and the largest single study to date included 50 people with TEA, TEA offers considerable theoretical significance as competing theories of human memory attempt to reconcile its implications.
Amnesia is a deficit in memory caused by brain damage or brain diseases, but it can also be temporarily caused by the use of various sedatives and hypnotic drugs. The memory can be either wholly or partially lost due to the extent of damage that was caused.
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.
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.
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.
Amygdalotomy is a form of psychosurgery which involves the surgical removal or destruction of the amygdala, or parts of the amygdala. It is usually a last-resort treatment for severe aggressive behavioral disorders and similar behaviors including hyperexcitability, violent outbursts, and self-mutilation. The practice of medical amygdalotomy typically involves the administration of general anesthesia and is achieved through the application of cranial stereotactic surgery to target regions of the amygdala for surgical destruction. While some studies have found stereotactic amygdalotomy in humans to be an effective treatment for severe cases of intractable aggressive behavior that has not responded to standard treatment methods, other studies remain inconclusive. In most cases of amygdalotomy in humans, there is no substantial evidence of impairment in overall cognitive function, including intelligence and working memory, however, deficits in specific areas of memory have been noted pertaining to the recognition and emotional interpretation of facial stimuli. This is because there are specialized cells in the amygdala which attend to facial stimuli.
Christine Kilpatrick is an Australian neurologist and the chief executive of Royal Melbourne Health. She has held this position since 2017. Previously, she was the chief executive of the Royal Children's Hospital from 2008 to 2017 and the executive director of Medical Services, Melbourne Health and executive director of the Royal Melbourne Hospital from 2004 to 2008. Before she held these positions, she worked as a neurologist at Royal Melbourne Health and engaged in extensive neurological research, especially epilepsy.
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.